diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index a2c893a7475d799ec0fd7c32a891f48141a6029a..ab65714d95fcec32b6103c384f05bd06ab84c506 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -304,57 +304,6 @@ tcp_low_latency - BOOLEAN
changed would be a Beowulf compute cluster.
Default: 0
-tcp_westwood - BOOLEAN
- Enable TCP Westwood+ congestion control algorithm.
- TCP Westwood+ is a sender-side only modification of the TCP Reno
- protocol stack that optimizes the performance of TCP congestion
- control. It is based on end-to-end bandwidth estimation to set
- congestion window and slow start threshold after a congestion
- episode. Using this estimation, TCP Westwood+ adaptively sets a
- slow start threshold and a congestion window which takes into
- account the bandwidth used at the time congestion is experienced.
- TCP Westwood+ significantly increases fairness wrt TCP Reno in
- wired networks and throughput over wireless links.
- Default: 0
-
-tcp_vegas_cong_avoid - BOOLEAN
- Enable TCP Vegas congestion avoidance algorithm.
- TCP Vegas is a sender-side only change to TCP that anticipates
- the onset of congestion by estimating the bandwidth. TCP Vegas
- adjusts the sending rate by modifying the congestion
- window. TCP Vegas should provide less packet loss, but it is
- not as aggressive as TCP Reno.
- Default:0
-
-tcp_bic - BOOLEAN
- Enable BIC TCP congestion control algorithm.
- BIC-TCP is a sender-side only change that ensures a linear RTT
- fairness under large windows while offering both scalability and
- bounded TCP-friendliness. The protocol combines two schemes
- called additive increase and binary search increase. When the
- congestion window is large, additive increase with a large
- increment ensures linear RTT fairness as well as good
- scalability. Under small congestion windows, binary search
- increase provides TCP friendliness.
- Default: 0
-
-tcp_bic_low_window - INTEGER
- Sets the threshold window (in packets) where BIC TCP starts to
- adjust the congestion window. Below this threshold BIC TCP behaves
- the same as the default TCP Reno.
- Default: 14
-
-tcp_bic_fast_convergence - BOOLEAN
- Forces BIC TCP to more quickly respond to changes in congestion
- window. Allows two flows sharing the same connection to converge
- more rapidly.
- Default: 1
-
-tcp_default_win_scale - INTEGER
- Sets the minimum window scale TCP will negotiate for on all
- conections.
- Default: 7
-
tcp_tso_win_divisor - INTEGER
This allows control over what percentage of the congestion window
can be consumed by a single TSO frame.
@@ -368,6 +317,11 @@ tcp_frto - BOOLEAN
where packet loss is typically due to random radio interference
rather than intermediate router congestion.
+tcp_congestion_control - STRING
+ Set the congestion control algorithm to be used for new
+ connections. The algorithm "reno" is always available, but
+ additional choices may be available based on kernel configuration.
+
somaxconn - INTEGER
Limit of socket listen() backlog, known in userspace as SOMAXCONN.
Defaults to 128. See also tcp_max_syn_backlog for additional tuning
diff --git a/Documentation/networking/tcp.txt b/Documentation/networking/tcp.txt
index 71749007091ee89943a94f3c0f9aecb8a0b2f07a..0fa300425575b4600594ba9f9edb017e09c60e2b 100644
--- a/Documentation/networking/tcp.txt
+++ b/Documentation/networking/tcp.txt
@@ -1,5 +1,72 @@
-How the new TCP output machine [nyi] works.
+TCP protocol
+============
+
+Last updated: 21 June 2005
+
+Contents
+========
+
+- Congestion control
+- How the new TCP output machine [nyi] works
+
+Congestion control
+==================
+
+The following variables are used in the tcp_sock for congestion control:
+snd_cwnd The size of the congestion window
+snd_ssthresh Slow start threshold. We are in slow start if
+ snd_cwnd is less than this.
+snd_cwnd_cnt A counter used to slow down the rate of increase
+ once we exceed slow start threshold.
+snd_cwnd_clamp This is the maximum size that snd_cwnd can grow to.
+snd_cwnd_stamp Timestamp for when congestion window last validated.
+snd_cwnd_used Used as a highwater mark for how much of the
+ congestion window is in use. It is used to adjust
+ snd_cwnd down when the link is limited by the
+ application rather than the network.
+
+As of 2.6.13, Linux supports pluggable congestion control algorithms.
+A congestion control mechanism can be registered through functions in
+tcp_cong.c. The functions used by the congestion control mechanism are
+registered via passing a tcp_congestion_ops struct to
+tcp_register_congestion_control. As a minimum name, ssthresh,
+cong_avoid, min_cwnd must be valid.
+Private data for a congestion control mechanism is stored in tp->ca_priv.
+tcp_ca(tp) returns a pointer to this space. This is preallocated space - it
+is important to check the size of your private data will fit this space, or
+alternatively space could be allocated elsewhere and a pointer to it could
+be stored here.
+
+There are three kinds of congestion control algorithms currently: The
+simplest ones are derived from TCP reno (highspeed, scalable) and just
+provide an alternative the congestion window calculation. More complex
+ones like BIC try to look at other events to provide better
+heuristics. There are also round trip time based algorithms like
+Vegas and Westwood+.
+
+Good TCP congestion control is a complex problem because the algorithm
+needs to maintain fairness and performance. Please review current
+research and RFC's before developing new modules.
+
+The method that is used to determine which congestion control mechanism is
+determined by the setting of the sysctl net.ipv4.tcp_congestion_control.
+The default congestion control will be the last one registered (LIFO);
+so if you built everything as modules. the default will be reno. If you
+build with the default's from Kconfig, then BIC will be builtin (not a module)
+and it will end up the default.
+
+If you really want a particular default value then you will need
+to set it with the sysctl. If you use a sysctl, the module will be autoloaded
+if needed and you will get the expected protocol. If you ask for an
+unknown congestion method, then the sysctl attempt will fail.
+
+If you remove a tcp congestion control module, then you will get the next
+available one. Since reno can not be built as a module, and can not be
+deleted, it will always be available.
+
+How the new TCP output machine [nyi] works.
+===========================================
Data is kept on a single queue. The skb->users flag tells us if the frame is
one that has been queued already. To add a frame we throw it on the end. Ack
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 614e939c78a4f915d7d58d7789a09f20c156bd58..72965bfe6cfb97e3fe375bdc886f399df505a7df 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -333,21 +333,14 @@ enum
NET_TCP_FRTO=92,
NET_TCP_LOW_LATENCY=93,
NET_IPV4_IPFRAG_SECRET_INTERVAL=94,
- NET_TCP_WESTWOOD=95,
NET_IPV4_IGMP_MAX_MSF=96,
NET_TCP_NO_METRICS_SAVE=97,
- NET_TCP_VEGAS=98,
- NET_TCP_VEGAS_ALPHA=99,
- NET_TCP_VEGAS_BETA=100,
- NET_TCP_VEGAS_GAMMA=101,
- NET_TCP_BIC=102,
- NET_TCP_BIC_FAST_CONVERGENCE=103,
- NET_TCP_BIC_LOW_WINDOW=104,
NET_TCP_DEFAULT_WIN_SCALE=105,
NET_TCP_MODERATE_RCVBUF=106,
NET_TCP_TSO_WIN_DIVISOR=107,
NET_TCP_BIC_BETA=108,
NET_IPV4_ICMP_ERRORS_USE_INBOUND_IFADDR=109,
+ NET_TCP_CONG_CONTROL=110,
};
enum {
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 97a7c9e03df5d9d5d2f60d4d88e64f26a49158a4..3ea75dd6640a8cb825dd69c9c9718cb6fd2f23f8 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -203,13 +203,6 @@ struct tcp_sack_block {
__u32 end_seq;
};
-enum tcp_congestion_algo {
- TCP_RENO=0,
- TCP_VEGAS,
- TCP_WESTWOOD,
- TCP_BIC,
-};
-
struct tcp_options_received {
/* PAWS/RTTM data */
long ts_recent_stamp;/* Time we stored ts_recent (for aging) */
@@ -305,7 +298,7 @@ struct tcp_sock {
__u8 reordering; /* Packet reordering metric. */
__u8 frto_counter; /* Number of new acks after RTO */
- __u8 adv_cong; /* Using Vegas, Westwood, or BIC */
+ __u8 unused;
__u8 defer_accept; /* User waits for some data after accept() */
/* RTT measurement */
@@ -401,37 +394,10 @@ struct tcp_sock {
__u32 time;
} rcvq_space;
-/* TCP Westwood structure */
- struct {
- __u32 bw_ns_est; /* first bandwidth estimation..not too smoothed 8) */
- __u32 bw_est; /* bandwidth estimate */
- __u32 rtt_win_sx; /* here starts a new evaluation... */
- __u32 bk;
- __u32 snd_una; /* used for evaluating the number of acked bytes */
- __u32 cumul_ack;
- __u32 accounted;
- __u32 rtt;
- __u32 rtt_min; /* minimum observed RTT */
- } westwood;
-
-/* Vegas variables */
- struct {
- __u32 beg_snd_nxt; /* right edge during last RTT */
- __u32 beg_snd_una; /* left edge during last RTT */
- __u32 beg_snd_cwnd; /* saves the size of the cwnd */
- __u8 doing_vegas_now;/* if true, do vegas for this RTT */
- __u16 cntRTT; /* # of RTTs measured within last RTT */
- __u32 minRTT; /* min of RTTs measured within last RTT (in usec) */
- __u32 baseRTT; /* the min of all Vegas RTT measurements seen (in usec) */
- } vegas;
-
- /* BI TCP Parameters */
- struct {
- __u32 cnt; /* increase cwnd by 1 after this number of ACKs */
- __u32 last_max_cwnd; /* last maximium snd_cwnd */
- __u32 last_cwnd; /* the last snd_cwnd */
- __u32 last_stamp; /* time when updated last_cwnd */
- } bictcp;
+ /* Pluggable TCP congestion control hook */
+ struct tcp_congestion_ops *ca_ops;
+ u32 ca_priv[16];
+#define TCP_CA_PRIV_SIZE (16*sizeof(u32))
};
static inline struct tcp_sock *tcp_sk(const struct sock *sk)
@@ -439,6 +405,11 @@ static inline struct tcp_sock *tcp_sk(const struct sock *sk)
return (struct tcp_sock *)sk;
}
+static inline void *tcp_ca(const struct tcp_sock *tp)
+{
+ return (void *) tp->ca_priv;
+}
+
#endif
#endif /* _LINUX_TCP_H */
diff --git a/include/linux/tcp_diag.h b/include/linux/tcp_diag.h
index ceee962e1d15a56262fe9b288cce886db6ff1dbe..7a5996743946806feecb65274be02b328508ca70 100644
--- a/include/linux/tcp_diag.h
+++ b/include/linux/tcp_diag.h
@@ -99,9 +99,10 @@ enum
TCPDIAG_MEMINFO,
TCPDIAG_INFO,
TCPDIAG_VEGASINFO,
+ TCPDIAG_CONG,
};
-#define TCPDIAG_MAX TCPDIAG_VEGASINFO
+#define TCPDIAG_MAX TCPDIAG_CONG
/* TCPDIAG_MEM */
@@ -123,5 +124,4 @@ struct tcpvegas_info {
__u32 tcpv_minrtt;
};
-
#endif /* _TCP_DIAG_H_ */
diff --git a/include/net/tcp.h b/include/net/tcp.h
index f730935b824ad6ca8e233705d253e322e291eb9e..e427cf35915c23476570e1097c57c634923ec929 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -505,25 +505,6 @@ static __inline__ int tcp_sk_listen_hashfn(struct sock *sk)
#else
# define TCP_TW_RECYCLE_TICK (12+2-TCP_TW_RECYCLE_SLOTS_LOG)
#endif
-
-#define BICTCP_BETA_SCALE 1024 /* Scale factor beta calculation
- * max_cwnd = snd_cwnd * beta
- */
-#define BICTCP_MAX_INCREMENT 32 /*
- * Limit on the amount of
- * increment allowed during
- * binary search.
- */
-#define BICTCP_FUNC_OF_MIN_INCR 11 /*
- * log(B/Smin)/log(B/(B-1))+1,
- * Smin:min increment
- * B:log factor
- */
-#define BICTCP_B 4 /*
- * In binary search,
- * go to point (max+min)/N
- */
-
/*
* TCP option
*/
@@ -596,16 +577,7 @@ extern int sysctl_tcp_adv_win_scale;
extern int sysctl_tcp_tw_reuse;
extern int sysctl_tcp_frto;
extern int sysctl_tcp_low_latency;
-extern int sysctl_tcp_westwood;
-extern int sysctl_tcp_vegas_cong_avoid;
-extern int sysctl_tcp_vegas_alpha;
-extern int sysctl_tcp_vegas_beta;
-extern int sysctl_tcp_vegas_gamma;
extern int sysctl_tcp_nometrics_save;
-extern int sysctl_tcp_bic;
-extern int sysctl_tcp_bic_fast_convergence;
-extern int sysctl_tcp_bic_low_window;
-extern int sysctl_tcp_bic_beta;
extern int sysctl_tcp_moderate_rcvbuf;
extern int sysctl_tcp_tso_win_divisor;
@@ -1136,6 +1108,80 @@ static inline void tcp_packets_out_dec(struct tcp_sock *tp,
tp->packets_out -= tcp_skb_pcount(skb);
}
+/* Events passed to congestion control interface */
+enum tcp_ca_event {
+ CA_EVENT_TX_START, /* first transmit when no packets in flight */
+ CA_EVENT_CWND_RESTART, /* congestion window restart */
+ CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */
+ CA_EVENT_FRTO, /* fast recovery timeout */
+ CA_EVENT_LOSS, /* loss timeout */
+ CA_EVENT_FAST_ACK, /* in sequence ack */
+ CA_EVENT_SLOW_ACK, /* other ack */
+};
+
+/*
+ * Interface for adding new TCP congestion control handlers
+ */
+#define TCP_CA_NAME_MAX 16
+struct tcp_congestion_ops {
+ struct list_head list;
+
+ /* initialize private data (optional) */
+ void (*init)(struct tcp_sock *tp);
+ /* cleanup private data (optional) */
+ void (*release)(struct tcp_sock *tp);
+
+ /* return slow start threshold (required) */
+ u32 (*ssthresh)(struct tcp_sock *tp);
+ /* lower bound for congestion window (optional) */
+ u32 (*min_cwnd)(struct tcp_sock *tp);
+ /* do new cwnd calculation (required) */
+ void (*cong_avoid)(struct tcp_sock *tp, u32 ack,
+ u32 rtt, u32 in_flight, int good_ack);
+ /* round trip time sample per acked packet (optional) */
+ void (*rtt_sample)(struct tcp_sock *tp, u32 usrtt);
+ /* call before changing ca_state (optional) */
+ void (*set_state)(struct tcp_sock *tp, u8 new_state);
+ /* call when cwnd event occurs (optional) */
+ void (*cwnd_event)(struct tcp_sock *tp, enum tcp_ca_event ev);
+ /* new value of cwnd after loss (optional) */
+ u32 (*undo_cwnd)(struct tcp_sock *tp);
+ /* hook for packet ack accounting (optional) */
+ void (*pkts_acked)(struct tcp_sock *tp, u32 num_acked);
+ /* get info for tcp_diag (optional) */
+ void (*get_info)(struct tcp_sock *tp, u32 ext, struct sk_buff *skb);
+
+ char name[TCP_CA_NAME_MAX];
+ struct module *owner;
+};
+
+extern int tcp_register_congestion_control(struct tcp_congestion_ops *type);
+extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type);
+
+extern void tcp_init_congestion_control(struct tcp_sock *tp);
+extern void tcp_cleanup_congestion_control(struct tcp_sock *tp);
+extern int tcp_set_default_congestion_control(const char *name);
+extern void tcp_get_default_congestion_control(char *name);
+
+extern struct tcp_congestion_ops tcp_reno;
+extern u32 tcp_reno_ssthresh(struct tcp_sock *tp);
+extern void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack,
+ u32 rtt, u32 in_flight, int flag);
+extern u32 tcp_reno_min_cwnd(struct tcp_sock *tp);
+
+static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state)
+{
+ if (tp->ca_ops->set_state)
+ tp->ca_ops->set_state(tp, ca_state);
+ tp->ca_state = ca_state;
+}
+
+static inline void tcp_ca_event(struct tcp_sock *tp, enum tcp_ca_event event)
+{
+ if (tp->ca_ops->cwnd_event)
+ tp->ca_ops->cwnd_event(tp, event);
+}
+
/* This determines how many packets are "in the network" to the best
* of our knowledge. In many cases it is conservative, but where
* detailed information is available from the receiver (via SACK
@@ -1155,91 +1201,6 @@ static __inline__ unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
return (tp->packets_out - tp->left_out + tp->retrans_out);
}
-/*
- * Which congestion algorithim is in use on the connection.
- */
-#define tcp_is_vegas(__tp) ((__tp)->adv_cong == TCP_VEGAS)
-#define tcp_is_westwood(__tp) ((__tp)->adv_cong == TCP_WESTWOOD)
-#define tcp_is_bic(__tp) ((__tp)->adv_cong == TCP_BIC)
-
-/* Recalculate snd_ssthresh, we want to set it to:
- *
- * Reno:
- * one half the current congestion window, but no
- * less than two segments
- *
- * BIC:
- * behave like Reno until low_window is reached,
- * then increase congestion window slowly
- */
-static inline __u32 tcp_recalc_ssthresh(struct tcp_sock *tp)
-{
- if (tcp_is_bic(tp)) {
- if (sysctl_tcp_bic_fast_convergence &&
- tp->snd_cwnd < tp->bictcp.last_max_cwnd)
- tp->bictcp.last_max_cwnd = (tp->snd_cwnd *
- (BICTCP_BETA_SCALE
- + sysctl_tcp_bic_beta))
- / (2 * BICTCP_BETA_SCALE);
- else
- tp->bictcp.last_max_cwnd = tp->snd_cwnd;
-
- if (tp->snd_cwnd > sysctl_tcp_bic_low_window)
- return max((tp->snd_cwnd * sysctl_tcp_bic_beta)
- / BICTCP_BETA_SCALE, 2U);
- }
-
- return max(tp->snd_cwnd >> 1U, 2U);
-}
-
-/* Stop taking Vegas samples for now. */
-#define tcp_vegas_disable(__tp) ((__tp)->vegas.doing_vegas_now = 0)
-
-static inline void tcp_vegas_enable(struct tcp_sock *tp)
-{
- /* There are several situations when we must "re-start" Vegas:
- *
- * o when a connection is established
- * o after an RTO
- * o after fast recovery
- * o when we send a packet and there is no outstanding
- * unacknowledged data (restarting an idle connection)
- *
- * In these circumstances we cannot do a Vegas calculation at the
- * end of the first RTT, because any calculation we do is using
- * stale info -- both the saved cwnd and congestion feedback are
- * stale.
- *
- * Instead we must wait until the completion of an RTT during
- * which we actually receive ACKs.
- */
-
- /* Begin taking Vegas samples next time we send something. */
- tp->vegas.doing_vegas_now = 1;
-
- /* Set the beginning of the next send window. */
- tp->vegas.beg_snd_nxt = tp->snd_nxt;
-
- tp->vegas.cntRTT = 0;
- tp->vegas.minRTT = 0x7fffffff;
-}
-
-/* Should we be taking Vegas samples right now? */
-#define tcp_vegas_enabled(__tp) ((__tp)->vegas.doing_vegas_now)
-
-extern void tcp_ca_init(struct tcp_sock *tp);
-
-static inline void tcp_set_ca_state(struct tcp_sock *tp, u8 ca_state)
-{
- if (tcp_is_vegas(tp)) {
- if (ca_state == TCP_CA_Open)
- tcp_vegas_enable(tp);
- else
- tcp_vegas_disable(tp);
- }
- tp->ca_state = ca_state;
-}
-
/* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd.
* The exception is rate halving phase, when cwnd is decreasing towards
* ssthresh.
@@ -1288,7 +1249,7 @@ static inline void tcp_cwnd_validate(struct sock *sk, struct tcp_sock *tp)
static inline void __tcp_enter_cwr(struct tcp_sock *tp)
{
tp->undo_marker = 0;
- tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
+ tp->snd_ssthresh = tp->ca_ops->ssthresh(tp);
tp->snd_cwnd = min(tp->snd_cwnd,
tcp_packets_in_flight(tp) + 1U);
tp->snd_cwnd_cnt = 0;
@@ -1876,52 +1837,4 @@ struct tcp_iter_state {
extern int tcp_proc_register(struct tcp_seq_afinfo *afinfo);
extern void tcp_proc_unregister(struct tcp_seq_afinfo *afinfo);
-/* TCP Westwood functions and constants */
-
-#define TCP_WESTWOOD_INIT_RTT (20*HZ) /* maybe too conservative?! */
-#define TCP_WESTWOOD_RTT_MIN (HZ/20) /* 50ms */
-
-static inline void tcp_westwood_update_rtt(struct tcp_sock *tp, __u32 rtt_seq)
-{
- if (tcp_is_westwood(tp))
- tp->westwood.rtt = rtt_seq;
-}
-
-static inline __u32 __tcp_westwood_bw_rttmin(const struct tcp_sock *tp)
-{
- return max((tp->westwood.bw_est) * (tp->westwood.rtt_min) /
- (__u32) (tp->mss_cache_std),
- 2U);
-}
-
-static inline __u32 tcp_westwood_bw_rttmin(const struct tcp_sock *tp)
-{
- return tcp_is_westwood(tp) ? __tcp_westwood_bw_rttmin(tp) : 0;
-}
-
-static inline int tcp_westwood_ssthresh(struct tcp_sock *tp)
-{
- __u32 ssthresh = 0;
-
- if (tcp_is_westwood(tp)) {
- ssthresh = __tcp_westwood_bw_rttmin(tp);
- if (ssthresh)
- tp->snd_ssthresh = ssthresh;
- }
-
- return (ssthresh != 0);
-}
-
-static inline int tcp_westwood_cwnd(struct tcp_sock *tp)
-{
- __u32 cwnd = 0;
-
- if (tcp_is_westwood(tp)) {
- cwnd = __tcp_westwood_bw_rttmin(tp);
- if (cwnd)
- tp->snd_cwnd = cwnd;
- }
-
- return (cwnd != 0);
-}
#endif /* _TCP_H */
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 567b03b1c349c3bfd4a7ba3ec5110bd3c0e474bb..690e88ba24846296c8c957da52ca5966bf142584 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -433,5 +433,95 @@ config IP_TCPDIAG
config IP_TCPDIAG_IPV6
def_bool (IP_TCPDIAG=y && IPV6=y) || (IP_TCPDIAG=m && IPV6)
+# TCP Reno is builtin (required as fallback)
+menu "TCP congestion control"
+ depends on INET
+
+config TCP_CONG_BIC
+ tristate "Binary Increase Congestion (BIC) control"
+ depends on INET
+ default y
+ ---help---
+ BIC-TCP is a sender-side only change that ensures a linear RTT
+ fairness under large windows while offering both scalability and
+ bounded TCP-friendliness. The protocol combines two schemes
+ called additive increase and binary search increase. When the
+ congestion window is large, additive increase with a large
+ increment ensures linear RTT fairness as well as good
+ scalability. Under small congestion windows, binary search
+ increase provides TCP friendliness.
+ See http://www.csc.ncsu.edu/faculty/rhee/export/bitcp/
+
+config TCP_CONG_WESTWOOD
+ tristate "TCP Westwood+"
+ depends on INET
+ default m
+ ---help---
+ TCP Westwood+ is a sender-side only modification of the TCP Reno
+ protocol stack that optimizes the performance of TCP congestion
+ control. It is based on end-to-end bandwidth estimation to set
+ congestion window and slow start threshold after a congestion
+ episode. Using this estimation, TCP Westwood+ adaptively sets a
+ slow start threshold and a congestion window which takes into
+ account the bandwidth used at the time congestion is experienced.
+ TCP Westwood+ significantly increases fairness wrt TCP Reno in
+ wired networks and throughput over wireless links.
+
+config TCP_CONG_HTCP
+ tristate "H-TCP"
+ depends on INET
+ default m
+ ---help---
+ H-TCP is a send-side only modifications of the TCP Reno
+ protocol stack that optimizes the performance of TCP
+ congestion control for high speed network links. It uses a
+ modeswitch to change the alpha and beta parameters of TCP Reno
+ based on network conditions and in a way so as to be fair with
+ other Reno and H-TCP flows.
+
+config TCP_CONG_HSTCP
+ tristate "High Speed TCP"
+ depends on INET && EXPERIMENTAL
+ default n
+ ---help---
+ Sally Floyd's High Speed TCP (RFC 3649) congestion control.
+ A modification to TCP's congestion control mechanism for use
+ with large congestion windows. A table indicates how much to
+ increase the congestion window by when an ACK is received.
+ For more detail see http://www.icir.org/floyd/hstcp.html
+
+config TCP_CONG_HYBLA
+ tristate "TCP-Hybla congestion control algorithm"
+ depends on INET && EXPERIMENTAL
+ default n
+ ---help---
+ TCP-Hybla is a sender-side only change that eliminates penalization of
+ long-RTT, large-bandwidth connections, like when satellite legs are
+ involved, expecially when sharing a common bottleneck with normal
+ terrestrial connections.
+
+config TCP_CONG_VEGAS
+ tristate "TCP Vegas"
+ depends on INET && EXPERIMENTAL
+ default n
+ ---help---
+ TCP Vegas is a sender-side only change to TCP that anticipates
+ the onset of congestion by estimating the bandwidth. TCP Vegas
+ adjusts the sending rate by modifying the congestion
+ window. TCP Vegas should provide less packet loss, but it is
+ not as aggressive as TCP Reno.
+
+config TCP_CONG_SCALABLE
+ tristate "Scalable TCP"
+ depends on INET && EXPERIMENTAL
+ default n
+ ---help---
+ Scalable TCP is a sender-side only change to TCP which uses a
+ MIMD congestion control algorithm which has some nice scaling
+ properties, though is known to have fairness issues.
+ See http://www-lce.eng.cam.ac.uk/~ctk21/scalable/
+
+endmenu
+
source "net/ipv4/ipvs/Kconfig"
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 65d57d8e1add2de4c53595b7f4d02b9644e69a82..5718cdb3a61e5e5972a2f634422e14b1bd462a2d 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -5,7 +5,8 @@
obj-y := utils.o route.o inetpeer.o protocol.o \
ip_input.o ip_fragment.o ip_forward.o ip_options.o \
ip_output.o ip_sockglue.o \
- tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o tcp_minisocks.o \
+ tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
+ tcp_minisocks.o tcp_cong.o \
datagram.o raw.o udp.o arp.o icmp.o devinet.o af_inet.o igmp.o \
sysctl_net_ipv4.o fib_frontend.o fib_semantics.o
@@ -30,6 +31,13 @@ obj-$(CONFIG_NETFILTER) += netfilter/
obj-$(CONFIG_IP_VS) += ipvs/
obj-$(CONFIG_IP_TCPDIAG) += tcp_diag.o
obj-$(CONFIG_IP_ROUTE_MULTIPATH_CACHED) += multipath.o
+obj-$(CONFIG_TCP_CONG_BIC) += tcp_bic.o
+obj-$(CONFIG_TCP_CONG_WESTWOOD) += tcp_westwood.o
+obj-$(CONFIG_TCP_CONG_HSTCP) += tcp_highspeed.o
+obj-$(CONFIG_TCP_CONG_HYBLA) += tcp_hybla.o
+obj-$(CONFIG_TCP_CONG_HTCP) += tcp_htcp.o
+obj-$(CONFIG_TCP_CONG_VEGAS) += tcp_vegas.o
+obj-$(CONFIG_TCP_CONG_SCALABLE) += tcp_scalable.o
obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \
xfrm4_output.o
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 23068bddbf0bb6837edc01ff2f2f8cd34a12c357..e32894532416ed0381368fb6b09b99318356ec3f 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -118,6 +118,45 @@ static int ipv4_sysctl_forward_strategy(ctl_table *table,
return 1;
}
+static int proc_tcp_congestion_control(ctl_table *ctl, int write, struct file * filp,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ char val[TCP_CA_NAME_MAX];
+ ctl_table tbl = {
+ .data = val,
+ .maxlen = TCP_CA_NAME_MAX,
+ };
+ int ret;
+
+ tcp_get_default_congestion_control(val);
+
+ ret = proc_dostring(&tbl, write, filp, buffer, lenp, ppos);
+ if (write && ret == 0)
+ ret = tcp_set_default_congestion_control(val);
+ return ret;
+}
+
+int sysctl_tcp_congestion_control(ctl_table *table, int __user *name, int nlen,
+ void __user *oldval, size_t __user *oldlenp,
+ void __user *newval, size_t newlen,
+ void **context)
+{
+ char val[TCP_CA_NAME_MAX];
+ ctl_table tbl = {
+ .data = val,
+ .maxlen = TCP_CA_NAME_MAX,
+ };
+ int ret;
+
+ tcp_get_default_congestion_control(val);
+ ret = sysctl_string(&tbl, name, nlen, oldval, oldlenp, newval, newlen,
+ context);
+ if (ret == 0 && newval && newlen)
+ ret = tcp_set_default_congestion_control(val);
+ return ret;
+}
+
+
ctl_table ipv4_table[] = {
{
.ctl_name = NET_IPV4_TCP_TIMESTAMPS,
@@ -611,70 +650,6 @@ ctl_table ipv4_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
- {
- .ctl_name = NET_TCP_WESTWOOD,
- .procname = "tcp_westwood",
- .data = &sysctl_tcp_westwood,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
- {
- .ctl_name = NET_TCP_VEGAS,
- .procname = "tcp_vegas_cong_avoid",
- .data = &sysctl_tcp_vegas_cong_avoid,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
- {
- .ctl_name = NET_TCP_VEGAS_ALPHA,
- .procname = "tcp_vegas_alpha",
- .data = &sysctl_tcp_vegas_alpha,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
- {
- .ctl_name = NET_TCP_VEGAS_BETA,
- .procname = "tcp_vegas_beta",
- .data = &sysctl_tcp_vegas_beta,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
- {
- .ctl_name = NET_TCP_VEGAS_GAMMA,
- .procname = "tcp_vegas_gamma",
- .data = &sysctl_tcp_vegas_gamma,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
- {
- .ctl_name = NET_TCP_BIC,
- .procname = "tcp_bic",
- .data = &sysctl_tcp_bic,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
- {
- .ctl_name = NET_TCP_BIC_FAST_CONVERGENCE,
- .procname = "tcp_bic_fast_convergence",
- .data = &sysctl_tcp_bic_fast_convergence,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
- {
- .ctl_name = NET_TCP_BIC_LOW_WINDOW,
- .procname = "tcp_bic_low_window",
- .data = &sysctl_tcp_bic_low_window,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = &proc_dointvec,
- },
{
.ctl_name = NET_TCP_MODERATE_RCVBUF,
.procname = "tcp_moderate_rcvbuf",
@@ -692,13 +667,14 @@ ctl_table ipv4_table[] = {
.proc_handler = &proc_dointvec,
},
{
- .ctl_name = NET_TCP_BIC_BETA,
- .procname = "tcp_bic_beta",
- .data = &sysctl_tcp_bic_beta,
- .maxlen = sizeof(int),
+ .ctl_name = NET_TCP_CONG_CONTROL,
+ .procname = "tcp_congestion_control",
.mode = 0644,
- .proc_handler = &proc_dointvec,
+ .maxlen = TCP_CA_NAME_MAX,
+ .proc_handler = &proc_tcp_congestion_control,
+ .strategy = &sysctl_tcp_congestion_control,
},
+
{ .ctl_name = 0 }
};
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 674bbd8cfd36d03c98dafa1770fc5daccb2b13f0..f3dbc8dc126346822b4a1e1f4116b5caf51c1013 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2333,6 +2333,8 @@ void __init tcp_init(void)
printk(KERN_INFO "TCP: Hash tables configured "
"(established %d bind %d)\n",
tcp_ehash_size << 1, tcp_bhash_size);
+
+ tcp_register_congestion_control(&tcp_reno);
}
EXPORT_SYMBOL(tcp_accept);
diff --git a/net/ipv4/tcp_bic.c b/net/ipv4/tcp_bic.c
new file mode 100644
index 0000000000000000000000000000000000000000..ec38d45d6649633178c8d541a34499349443c8a4
--- /dev/null
+++ b/net/ipv4/tcp_bic.c
@@ -0,0 +1,331 @@
+/*
+ * Binary Increase Congestion control for TCP
+ *
+ * This is from the implementation of BICTCP in
+ * Lison-Xu, Kahaled Harfoush, and Injong Rhee.
+ * "Binary Increase Congestion Control for Fast, Long Distance
+ * Networks" in InfoComm 2004
+ * Available from:
+ * http://www.csc.ncsu.edu/faculty/rhee/export/bitcp.pdf
+ *
+ * Unless BIC is enabled and congestion window is large
+ * this behaves the same as the original Reno.
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <net/tcp.h>
+
+
+#define BICTCP_BETA_SCALE 1024 /* Scale factor beta calculation
+ * max_cwnd = snd_cwnd * beta
+ */
+#define BICTCP_B 4 /*
+ * In binary search,
+ * go to point (max+min)/N
+ */
+
+static int fast_convergence = 1;
+static int max_increment = 32;
+static int low_window = 14;
+static int beta = 819; /* = 819/1024 (BICTCP_BETA_SCALE) */
+static int low_utilization_threshold = 153;
+static int low_utilization_period = 2;
+static int initial_ssthresh = 100;
+static int smooth_part = 20;
+
+module_param(fast_convergence, int, 0644);
+MODULE_PARM_DESC(fast_convergence, "turn on/off fast convergence");
+module_param(max_increment, int, 0644);
+MODULE_PARM_DESC(max_increment, "Limit on increment allowed during binary search");
+module_param(low_window, int, 0644);
+MODULE_PARM_DESC(low_window, "lower bound on congestion window (for TCP friendliness)");
+module_param(beta, int, 0644);
+MODULE_PARM_DESC(beta, "beta for multiplicative increase");
+module_param(low_utilization_threshold, int, 0644);
+MODULE_PARM_DESC(low_utilization_threshold, "percent (scaled by 1024) for low utilization mode");
+module_param(low_utilization_period, int, 0644);
+MODULE_PARM_DESC(low_utilization_period, "if average delay exceeds then goto to low utilization mode (seconds)");
+module_param(initial_ssthresh, int, 0644);
+MODULE_PARM_DESC(initial_ssthresh, "initial value of slow start threshold");
+module_param(smooth_part, int, 0644);
+MODULE_PARM_DESC(smooth_part, "log(B/(B*Smin))/log(B/(B-1))+B, # of RTT from Wmax-B to Wmax");
+
+
+/* BIC TCP Parameters */
+struct bictcp {
+ u32 cnt; /* increase cwnd by 1 after ACKs */
+ u32 last_max_cwnd; /* last maximum snd_cwnd */
+ u32 loss_cwnd; /* congestion window at last loss */
+ u32 last_cwnd; /* the last snd_cwnd */
+ u32 last_time; /* time when updated last_cwnd */
+ u32 delay_min; /* min delay */
+ u32 delay_max; /* max delay */
+ u32 last_delay;
+ u8 low_utilization;/* 0: high; 1: low */
+ u32 low_utilization_start; /* starting time of low utilization detection*/
+ u32 epoch_start; /* beginning of an epoch */
+#define ACK_RATIO_SHIFT 4
+ u32 delayed_ack; /* estimate the ratio of Packets/ACKs << 4 */
+};
+
+static inline void bictcp_reset(struct bictcp *ca)
+{
+ ca->cnt = 0;
+ ca->last_max_cwnd = 0;
+ ca->loss_cwnd = 0;
+ ca->last_cwnd = 0;
+ ca->last_time = 0;
+ ca->delay_min = 0;
+ ca->delay_max = 0;
+ ca->last_delay = 0;
+ ca->low_utilization = 0;
+ ca->low_utilization_start = 0;
+ ca->epoch_start = 0;
+ ca->delayed_ack = 2 << ACK_RATIO_SHIFT;
+}
+
+static void bictcp_init(struct tcp_sock *tp)
+{
+ bictcp_reset(tcp_ca(tp));
+ if (initial_ssthresh)
+ tp->snd_ssthresh = initial_ssthresh;
+}
+
+/*
+ * Compute congestion window to use.
+ */
+static inline void bictcp_update(struct bictcp *ca, u32 cwnd)
+{
+ if (ca->last_cwnd == cwnd &&
+ (s32)(tcp_time_stamp - ca->last_time) <= HZ / 32)
+ return;
+
+ ca->last_cwnd = cwnd;
+ ca->last_time = tcp_time_stamp;
+
+ if (ca->epoch_start == 0) /* record the beginning of an epoch */
+ ca->epoch_start = tcp_time_stamp;
+
+ /* start off normal */
+ if (cwnd <= low_window) {
+ ca->cnt = cwnd;
+ return;
+ }
+
+ /* binary increase */
+ if (cwnd < ca->last_max_cwnd) {
+ __u32 dist = (ca->last_max_cwnd - cwnd)
+ / BICTCP_B;
+
+ if (dist > max_increment)
+ /* linear increase */
+ ca->cnt = cwnd / max_increment;
+ else if (dist <= 1U)
+ /* binary search increase */
+ ca->cnt = (cwnd * smooth_part) / BICTCP_B;
+ else
+ /* binary search increase */
+ ca->cnt = cwnd / dist;
+ } else {
+ /* slow start AMD linear increase */
+ if (cwnd < ca->last_max_cwnd + BICTCP_B)
+ /* slow start */
+ ca->cnt = (cwnd * smooth_part) / BICTCP_B;
+ else if (cwnd < ca->last_max_cwnd + max_increment*(BICTCP_B-1))
+ /* slow start */
+ ca->cnt = (cwnd * (BICTCP_B-1))
+ / cwnd-ca->last_max_cwnd;
+ else
+ /* linear increase */
+ ca->cnt = cwnd / max_increment;
+ }
+
+ /* if in slow start or link utilization is very low */
+ if ( ca->loss_cwnd == 0 ||
+ (cwnd > ca->loss_cwnd && ca->low_utilization)) {
+ if (ca->cnt > 20) /* increase cwnd 5% per RTT */
+ ca->cnt = 20;
+ }
+
+ ca->cnt = (ca->cnt << ACK_RATIO_SHIFT) / ca->delayed_ack;
+ if (ca->cnt == 0) /* cannot be zero */
+ ca->cnt = 1;
+}
+
+
+/* Detect low utilization in congestion avoidance */
+static inline void bictcp_low_utilization(struct tcp_sock *tp, int flag)
+{
+ struct bictcp *ca = tcp_ca(tp);
+ u32 dist, delay;
+
+ /* No time stamp */
+ if (!(tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr) ||
+ /* Discard delay samples right after fast recovery */
+ tcp_time_stamp < ca->epoch_start + HZ ||
+ /* this delay samples may not be accurate */
+ flag == 0) {
+ ca->last_delay = 0;
+ goto notlow;
+ }
+
+ delay = ca->last_delay<<3; /* use the same scale as tp->srtt*/
+ ca->last_delay = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
+ if (delay == 0) /* no previous delay sample */
+ goto notlow;
+
+ /* first time call or link delay decreases */
+ if (ca->delay_min == 0 || ca->delay_min > delay) {
+ ca->delay_min = ca->delay_max = delay;
+ goto notlow;
+ }
+
+ if (ca->delay_max < delay)
+ ca->delay_max = delay;
+
+ /* utilization is low, if avg delay < dist*threshold
+ for checking_period time */
+ dist = ca->delay_max - ca->delay_min;
+ if (dist <= ca->delay_min>>6 ||
+ tp->srtt - ca->delay_min >= (dist*low_utilization_threshold)>>10)
+ goto notlow;
+
+ if (ca->low_utilization_start == 0) {
+ ca->low_utilization = 0;
+ ca->low_utilization_start = tcp_time_stamp;
+ } else if ((s32)(tcp_time_stamp - ca->low_utilization_start)
+ > low_utilization_period*HZ) {
+ ca->low_utilization = 1;
+ }
+
+ return;
+
+ notlow:
+ ca->low_utilization = 0;
+ ca->low_utilization_start = 0;
+
+}
+
+static void bictcp_cong_avoid(struct tcp_sock *tp, u32 ack,
+ u32 seq_rtt, u32 in_flight, int data_acked)
+{
+ struct bictcp *ca = tcp_ca(tp);
+
+ bictcp_low_utilization(tp, data_acked);
+
+ if (in_flight < tp->snd_cwnd)
+ return;
+
+ if (tp->snd_cwnd <= tp->snd_ssthresh) {
+ /* In "safe" area, increase. */
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ tp->snd_cwnd++;
+ } else {
+ bictcp_update(ca, tp->snd_cwnd);
+
+ /* In dangerous area, increase slowly.
+ * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
+ */
+ if (tp->snd_cwnd_cnt >= ca->cnt) {
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ tp->snd_cwnd++;
+ tp->snd_cwnd_cnt = 0;
+ } else
+ tp->snd_cwnd_cnt++;
+ }
+
+}
+
+/*
+ * behave like Reno until low_window is reached,
+ * then increase congestion window slowly
+ */
+static u32 bictcp_recalc_ssthresh(struct tcp_sock *tp)
+{
+ struct bictcp *ca = tcp_ca(tp);
+
+ ca->epoch_start = 0; /* end of epoch */
+
+ /* in case of wrong delay_max*/
+ if (ca->delay_min > 0 && ca->delay_max > ca->delay_min)
+ ca->delay_max = ca->delay_min
+ + ((ca->delay_max - ca->delay_min)* 90) / 100;
+
+ /* Wmax and fast convergence */
+ if (tp->snd_cwnd < ca->last_max_cwnd && fast_convergence)
+ ca->last_max_cwnd = (tp->snd_cwnd * (BICTCP_BETA_SCALE + beta))
+ / (2 * BICTCP_BETA_SCALE);
+ else
+ ca->last_max_cwnd = tp->snd_cwnd;
+
+ ca->loss_cwnd = tp->snd_cwnd;
+
+
+ if (tp->snd_cwnd <= low_window)
+ return max(tp->snd_cwnd >> 1U, 2U);
+ else
+ return max((tp->snd_cwnd * beta) / BICTCP_BETA_SCALE, 2U);
+}
+
+static u32 bictcp_undo_cwnd(struct tcp_sock *tp)
+{
+ struct bictcp *ca = tcp_ca(tp);
+
+ return max(tp->snd_cwnd, ca->last_max_cwnd);
+}
+
+static u32 bictcp_min_cwnd(struct tcp_sock *tp)
+{
+ return tp->snd_ssthresh;
+}
+
+static void bictcp_state(struct tcp_sock *tp, u8 new_state)
+{
+ if (new_state == TCP_CA_Loss)
+ bictcp_reset(tcp_ca(tp));
+}
+
+/* Track delayed acknowledgement ratio using sliding window
+ * ratio = (15*ratio + sample) / 16
+ */
+static void bictcp_acked(struct tcp_sock *tp, u32 cnt)
+{
+ if (cnt > 0 && tp->ca_state == TCP_CA_Open) {
+ struct bictcp *ca = tcp_ca(tp);
+ cnt -= ca->delayed_ack >> ACK_RATIO_SHIFT;
+ ca->delayed_ack += cnt;
+ }
+}
+
+
+static struct tcp_congestion_ops bictcp = {
+ .init = bictcp_init,
+ .ssthresh = bictcp_recalc_ssthresh,
+ .cong_avoid = bictcp_cong_avoid,
+ .set_state = bictcp_state,
+ .undo_cwnd = bictcp_undo_cwnd,
+ .min_cwnd = bictcp_min_cwnd,
+ .pkts_acked = bictcp_acked,
+ .owner = THIS_MODULE,
+ .name = "bic",
+};
+
+static int __init bictcp_register(void)
+{
+ BUG_ON(sizeof(struct bictcp) > TCP_CA_PRIV_SIZE);
+ return tcp_register_congestion_control(&bictcp);
+}
+
+static void __exit bictcp_unregister(void)
+{
+ tcp_unregister_congestion_control(&bictcp);
+}
+
+module_init(bictcp_register);
+module_exit(bictcp_unregister);
+
+MODULE_AUTHOR("Stephen Hemminger");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("BIC TCP");
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
new file mode 100644
index 0000000000000000000000000000000000000000..665394a63ae4912cfe088e079923342914050758
--- /dev/null
+++ b/net/ipv4/tcp_cong.c
@@ -0,0 +1,195 @@
+/*
+ * Plugable TCP congestion control support and newReno
+ * congestion control.
+ * Based on ideas from I/O scheduler suport and Web100.
+ *
+ * Copyright (C) 2005 Stephen Hemminger <shemminger@osdl.org>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <net/tcp.h>
+
+static DEFINE_SPINLOCK(tcp_cong_list_lock);
+static LIST_HEAD(tcp_cong_list);
+
+/* Simple linear search, don't expect many entries! */
+static struct tcp_congestion_ops *tcp_ca_find(const char *name)
+{
+ struct tcp_congestion_ops *e;
+
+ list_for_each_entry(e, &tcp_cong_list, list) {
+ if (strcmp(e->name, name) == 0)
+ return e;
+ }
+
+ return NULL;
+}
+
+/*
+ * Attach new congestion control algorthim to the list
+ * of available options.
+ */
+int tcp_register_congestion_control(struct tcp_congestion_ops *ca)
+{
+ int ret = 0;
+
+ /* all algorithms must implement ssthresh and cong_avoid ops */
+ if (!ca->ssthresh || !ca->cong_avoid || !ca->min_cwnd) {
+ printk(KERN_ERR "TCP %s does not implement required ops\n",
+ ca->name);
+ return -EINVAL;
+ }
+
+ spin_lock(&tcp_cong_list_lock);
+ if (tcp_ca_find(ca->name)) {
+ printk(KERN_NOTICE "TCP %s already registered\n", ca->name);
+ ret = -EEXIST;
+ } else {
+ list_add_rcu(&ca->list, &tcp_cong_list);
+ printk(KERN_INFO "TCP %s registered\n", ca->name);
+ }
+ spin_unlock(&tcp_cong_list_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(tcp_register_congestion_control);
+
+/*
+ * Remove congestion control algorithm, called from
+ * the module's remove function. Module ref counts are used
+ * to ensure that this can't be done till all sockets using
+ * that method are closed.
+ */
+void tcp_unregister_congestion_control(struct tcp_congestion_ops *ca)
+{
+ spin_lock(&tcp_cong_list_lock);
+ list_del_rcu(&ca->list);
+ spin_unlock(&tcp_cong_list_lock);
+}
+EXPORT_SYMBOL_GPL(tcp_unregister_congestion_control);
+
+/* Assign choice of congestion control. */
+void tcp_init_congestion_control(struct tcp_sock *tp)
+{
+ struct tcp_congestion_ops *ca;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
+ if (try_module_get(ca->owner)) {
+ tp->ca_ops = ca;
+ break;
+ }
+
+ }
+ rcu_read_unlock();
+
+ if (tp->ca_ops->init)
+ tp->ca_ops->init(tp);
+}
+
+/* Manage refcounts on socket close. */
+void tcp_cleanup_congestion_control(struct tcp_sock *tp)
+{
+ if (tp->ca_ops->release)
+ tp->ca_ops->release(tp);
+ module_put(tp->ca_ops->owner);
+}
+
+/* Used by sysctl to change default congestion control */
+int tcp_set_default_congestion_control(const char *name)
+{
+ struct tcp_congestion_ops *ca;
+ int ret = -ENOENT;
+
+ spin_lock(&tcp_cong_list_lock);
+ ca = tcp_ca_find(name);
+#ifdef CONFIG_KMOD
+ if (!ca) {
+ spin_unlock(&tcp_cong_list_lock);
+
+ request_module("tcp_%s", name);
+ spin_lock(&tcp_cong_list_lock);
+ ca = tcp_ca_find(name);
+ }
+#endif
+
+ if (ca) {
+ list_move(&ca->list, &tcp_cong_list);
+ ret = 0;
+ }
+ spin_unlock(&tcp_cong_list_lock);
+
+ return ret;
+}
+
+/* Get current default congestion control */
+void tcp_get_default_congestion_control(char *name)
+{
+ struct tcp_congestion_ops *ca;
+ /* We will always have reno... */
+ BUG_ON(list_empty(&tcp_cong_list));
+
+ rcu_read_lock();
+ ca = list_entry(tcp_cong_list.next, struct tcp_congestion_ops, list);
+ strncpy(name, ca->name, TCP_CA_NAME_MAX);
+ rcu_read_unlock();
+}
+
+/*
+ * TCP Reno congestion control
+ * This is special case used for fallback as well.
+ */
+/* This is Jacobson's slow start and congestion avoidance.
+ * SIGCOMM '88, p. 328.
+ */
+void tcp_reno_cong_avoid(struct tcp_sock *tp, u32 ack, u32 rtt, u32 in_flight,
+ int flag)
+{
+ if (in_flight < tp->snd_cwnd)
+ return;
+
+ if (tp->snd_cwnd <= tp->snd_ssthresh) {
+ /* In "safe" area, increase. */
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ tp->snd_cwnd++;
+ } else {
+ /* In dangerous area, increase slowly.
+ * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
+ */
+ if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ tp->snd_cwnd++;
+ tp->snd_cwnd_cnt = 0;
+ } else
+ tp->snd_cwnd_cnt++;
+ }
+}
+EXPORT_SYMBOL_GPL(tcp_reno_cong_avoid);
+
+/* Slow start threshold is half the congestion window (min 2) */
+u32 tcp_reno_ssthresh(struct tcp_sock *tp)
+{
+ return max(tp->snd_cwnd >> 1U, 2U);
+}
+EXPORT_SYMBOL_GPL(tcp_reno_ssthresh);
+
+/* Lower bound on congestion window. */
+u32 tcp_reno_min_cwnd(struct tcp_sock *tp)
+{
+ return tp->snd_ssthresh/2;
+}
+EXPORT_SYMBOL_GPL(tcp_reno_min_cwnd);
+
+struct tcp_congestion_ops tcp_reno = {
+ .name = "reno",
+ .owner = THIS_MODULE,
+ .ssthresh = tcp_reno_ssthresh,
+ .cong_avoid = tcp_reno_cong_avoid,
+ .min_cwnd = tcp_reno_min_cwnd,
+};
+
+EXPORT_SYMBOL_GPL(tcp_reno);
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index 634befc079218e3520488a0904dd7f1f4d33ea53..f66945cb158fd346c0b2f87d0dec068620b7a838 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -42,15 +42,8 @@ struct tcpdiag_entry
static struct sock *tcpnl;
-
#define TCPDIAG_PUT(skb, attrtype, attrlen) \
-({ int rtalen = RTA_LENGTH(attrlen); \
- struct rtattr *rta; \
- if (skb_tailroom(skb) < RTA_ALIGN(rtalen)) goto nlmsg_failure; \
- rta = (void*)__skb_put(skb, RTA_ALIGN(rtalen)); \
- rta->rta_type = attrtype; \
- rta->rta_len = rtalen; \
- RTA_DATA(rta); })
+ RTA_DATA(__RTA_PUT(skb, attrtype, attrlen))
static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
int ext, u32 pid, u32 seq, u16 nlmsg_flags)
@@ -61,7 +54,6 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
struct nlmsghdr *nlh;
struct tcp_info *info = NULL;
struct tcpdiag_meminfo *minfo = NULL;
- struct tcpvegas_info *vinfo = NULL;
unsigned char *b = skb->tail;
nlh = NLMSG_PUT(skb, pid, seq, TCPDIAG_GETSOCK, sizeof(*r));
@@ -73,9 +65,11 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
if (ext & (1<<(TCPDIAG_INFO-1)))
info = TCPDIAG_PUT(skb, TCPDIAG_INFO, sizeof(*info));
- if ((tcp_is_westwood(tp) || tcp_is_vegas(tp))
- && (ext & (1<<(TCPDIAG_VEGASINFO-1))))
- vinfo = TCPDIAG_PUT(skb, TCPDIAG_VEGASINFO, sizeof(*vinfo));
+ if (ext & (1<<(TCPDIAG_CONG-1))) {
+ size_t len = strlen(tp->ca_ops->name);
+ strcpy(TCPDIAG_PUT(skb, TCPDIAG_CONG, len+1),
+ tp->ca_ops->name);
+ }
}
r->tcpdiag_family = sk->sk_family;
r->tcpdiag_state = sk->sk_state;
@@ -166,23 +160,13 @@ static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
if (info)
tcp_get_info(sk, info);
- if (vinfo) {
- if (tcp_is_vegas(tp)) {
- vinfo->tcpv_enabled = tp->vegas.doing_vegas_now;
- vinfo->tcpv_rttcnt = tp->vegas.cntRTT;
- vinfo->tcpv_rtt = jiffies_to_usecs(tp->vegas.baseRTT);
- vinfo->tcpv_minrtt = jiffies_to_usecs(tp->vegas.minRTT);
- } else {
- vinfo->tcpv_enabled = 0;
- vinfo->tcpv_rttcnt = 0;
- vinfo->tcpv_rtt = jiffies_to_usecs(tp->westwood.rtt);
- vinfo->tcpv_minrtt = jiffies_to_usecs(tp->westwood.rtt_min);
- }
- }
+ if (sk->sk_state < TCP_TIME_WAIT && tp->ca_ops->get_info)
+ tp->ca_ops->get_info(tp, ext, skb);
nlh->nlmsg_len = skb->tail - b;
return skb->len;
+rtattr_failure:
nlmsg_failure:
skb_trim(skb, b - skb->data);
return -1;
diff --git a/net/ipv4/tcp_highspeed.c b/net/ipv4/tcp_highspeed.c
new file mode 100644
index 0000000000000000000000000000000000000000..36c51f8136bfa6aae3bb1f3f3abf12889673c799
--- /dev/null
+++ b/net/ipv4/tcp_highspeed.c
@@ -0,0 +1,181 @@
+/*
+ * Sally Floyd's High Speed TCP (RFC 3649) congestion control
+ *
+ * See http://www.icir.org/floyd/hstcp.html
+ *
+ * John Heffner <jheffner@psc.edu>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <net/tcp.h>
+
+
+/* From AIMD tables from RFC 3649 appendix B,
+ * with fixed-point MD scaled <<8.
+ */
+static const struct hstcp_aimd_val {
+ unsigned int cwnd;
+ unsigned int md;
+} hstcp_aimd_vals[] = {
+ { 38, 128, /* 0.50 */ },
+ { 118, 112, /* 0.44 */ },
+ { 221, 104, /* 0.41 */ },
+ { 347, 98, /* 0.38 */ },
+ { 495, 93, /* 0.37 */ },
+ { 663, 89, /* 0.35 */ },
+ { 851, 86, /* 0.34 */ },
+ { 1058, 83, /* 0.33 */ },
+ { 1284, 81, /* 0.32 */ },
+ { 1529, 78, /* 0.31 */ },
+ { 1793, 76, /* 0.30 */ },
+ { 2076, 74, /* 0.29 */ },
+ { 2378, 72, /* 0.28 */ },
+ { 2699, 71, /* 0.28 */ },
+ { 3039, 69, /* 0.27 */ },
+ { 3399, 68, /* 0.27 */ },
+ { 3778, 66, /* 0.26 */ },
+ { 4177, 65, /* 0.26 */ },
+ { 4596, 64, /* 0.25 */ },
+ { 5036, 62, /* 0.25 */ },
+ { 5497, 61, /* 0.24 */ },
+ { 5979, 60, /* 0.24 */ },
+ { 6483, 59, /* 0.23 */ },
+ { 7009, 58, /* 0.23 */ },
+ { 7558, 57, /* 0.22 */ },
+ { 8130, 56, /* 0.22 */ },
+ { 8726, 55, /* 0.22 */ },
+ { 9346, 54, /* 0.21 */ },
+ { 9991, 53, /* 0.21 */ },
+ { 10661, 52, /* 0.21 */ },
+ { 11358, 52, /* 0.20 */ },
+ { 12082, 51, /* 0.20 */ },
+ { 12834, 50, /* 0.20 */ },
+ { 13614, 49, /* 0.19 */ },
+ { 14424, 48, /* 0.19 */ },
+ { 15265, 48, /* 0.19 */ },
+ { 16137, 47, /* 0.19 */ },
+ { 17042, 46, /* 0.18 */ },
+ { 17981, 45, /* 0.18 */ },
+ { 18955, 45, /* 0.18 */ },
+ { 19965, 44, /* 0.17 */ },
+ { 21013, 43, /* 0.17 */ },
+ { 22101, 43, /* 0.17 */ },
+ { 23230, 42, /* 0.17 */ },
+ { 24402, 41, /* 0.16 */ },
+ { 25618, 41, /* 0.16 */ },
+ { 26881, 40, /* 0.16 */ },
+ { 28193, 39, /* 0.16 */ },
+ { 29557, 39, /* 0.15 */ },
+ { 30975, 38, /* 0.15 */ },
+ { 32450, 38, /* 0.15 */ },
+ { 33986, 37, /* 0.15 */ },
+ { 35586, 36, /* 0.14 */ },
+ { 37253, 36, /* 0.14 */ },
+ { 38992, 35, /* 0.14 */ },
+ { 40808, 35, /* 0.14 */ },
+ { 42707, 34, /* 0.13 */ },
+ { 44694, 33, /* 0.13 */ },
+ { 46776, 33, /* 0.13 */ },
+ { 48961, 32, /* 0.13 */ },
+ { 51258, 32, /* 0.13 */ },
+ { 53677, 31, /* 0.12 */ },
+ { 56230, 30, /* 0.12 */ },
+ { 58932, 30, /* 0.12 */ },
+ { 61799, 29, /* 0.12 */ },
+ { 64851, 28, /* 0.11 */ },
+ { 68113, 28, /* 0.11 */ },
+ { 71617, 27, /* 0.11 */ },
+ { 75401, 26, /* 0.10 */ },
+ { 79517, 26, /* 0.10 */ },
+ { 84035, 25, /* 0.10 */ },
+ { 89053, 24, /* 0.10 */ },
+};
+
+#define HSTCP_AIMD_MAX ARRAY_SIZE(hstcp_aimd_vals)
+
+struct hstcp {
+ u32 ai;
+};
+
+static void hstcp_init(struct tcp_sock *tp)
+{
+ struct hstcp *ca = tcp_ca(tp);
+
+ ca->ai = 0;
+
+ /* Ensure the MD arithmetic works. This is somewhat pedantic,
+ * since I don't think we will see a cwnd this large. :) */
+ tp->snd_cwnd_clamp = min_t(u32, tp->snd_cwnd_clamp, 0xffffffff/128);
+}
+
+static void hstcp_cong_avoid(struct tcp_sock *tp, u32 adk, u32 rtt,
+ u32 in_flight, int good)
+{
+ struct hstcp *ca = tcp_ca(tp);
+
+ if (in_flight < tp->snd_cwnd)
+ return;
+
+ if (tp->snd_cwnd <= tp->snd_ssthresh) {
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ tp->snd_cwnd++;
+ } else {
+ /* Update AIMD parameters */
+ if (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd) {
+ while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd &&
+ ca->ai < HSTCP_AIMD_MAX)
+ ca->ai++;
+ } else if (tp->snd_cwnd < hstcp_aimd_vals[ca->ai].cwnd) {
+ while (tp->snd_cwnd > hstcp_aimd_vals[ca->ai].cwnd &&
+ ca->ai > 0)
+ ca->ai--;
+ }
+
+ /* Do additive increase */
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp) {
+ tp->snd_cwnd_cnt += ca->ai;
+ if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+ tp->snd_cwnd++;
+ tp->snd_cwnd_cnt -= tp->snd_cwnd;
+ }
+ }
+ }
+}
+
+static u32 hstcp_ssthresh(struct tcp_sock *tp)
+{
+ struct hstcp *ca = tcp_ca(tp);
+
+ /* Do multiplicative decrease */
+ return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U);
+}
+
+
+static struct tcp_congestion_ops tcp_highspeed = {
+ .init = hstcp_init,
+ .ssthresh = hstcp_ssthresh,
+ .cong_avoid = hstcp_cong_avoid,
+ .min_cwnd = tcp_reno_min_cwnd,
+
+ .owner = THIS_MODULE,
+ .name = "highspeed"
+};
+
+static int __init hstcp_register(void)
+{
+ BUG_ON(sizeof(struct hstcp) > TCP_CA_PRIV_SIZE);
+ return tcp_register_congestion_control(&tcp_highspeed);
+}
+
+static void __exit hstcp_unregister(void)
+{
+ tcp_unregister_congestion_control(&tcp_highspeed);
+}
+
+module_init(hstcp_register);
+module_exit(hstcp_unregister);
+
+MODULE_AUTHOR("John Heffner");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("High Speed TCP");
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c
new file mode 100644
index 0000000000000000000000000000000000000000..40168275acf9d278c6a6bedb768a2c06640a4a41
--- /dev/null
+++ b/net/ipv4/tcp_htcp.c
@@ -0,0 +1,289 @@
+/*
+ * H-TCP congestion control. The algorithm is detailed in:
+ * R.N.Shorten, D.J.Leith:
+ * "H-TCP: TCP for high-speed and long-distance networks"
+ * Proc. PFLDnet, Argonne, 2004.
+ * http://www.hamilton.ie/net/htcp3.pdf
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <net/tcp.h>
+
+#define ALPHA_BASE (1<<7) /* 1.0 with shift << 7 */
+#define BETA_MIN (1<<6) /* 0.5 with shift << 7 */
+#define BETA_MAX 102 /* 0.8 with shift << 7 */
+
+static int use_rtt_scaling = 1;
+module_param(use_rtt_scaling, int, 0644);
+MODULE_PARM_DESC(use_rtt_scaling, "turn on/off RTT scaling");
+
+static int use_bandwidth_switch = 1;
+module_param(use_bandwidth_switch, int, 0644);
+MODULE_PARM_DESC(use_bandwidth_switch, "turn on/off bandwidth switcher");
+
+struct htcp {
+ u16 alpha; /* Fixed point arith, << 7 */
+ u8 beta; /* Fixed point arith, << 7 */
+ u8 modeswitch; /* Delay modeswitch until we had at least one congestion event */
+ u8 ccount; /* Number of RTTs since last congestion event */
+ u8 undo_ccount;
+ u16 packetcount;
+ u32 minRTT;
+ u32 maxRTT;
+ u32 snd_cwnd_cnt2;
+
+ u32 undo_maxRTT;
+ u32 undo_old_maxB;
+
+ /* Bandwidth estimation */
+ u32 minB;
+ u32 maxB;
+ u32 old_maxB;
+ u32 Bi;
+ u32 lasttime;
+};
+
+static inline void htcp_reset(struct htcp *ca)
+{
+ ca->undo_ccount = ca->ccount;
+ ca->undo_maxRTT = ca->maxRTT;
+ ca->undo_old_maxB = ca->old_maxB;
+
+ ca->ccount = 0;
+ ca->snd_cwnd_cnt2 = 0;
+}
+
+static u32 htcp_cwnd_undo(struct tcp_sock *tp)
+{
+ struct htcp *ca = tcp_ca(tp);
+ ca->ccount = ca->undo_ccount;
+ ca->maxRTT = ca->undo_maxRTT;
+ ca->old_maxB = ca->undo_old_maxB;
+ return max(tp->snd_cwnd, (tp->snd_ssthresh<<7)/ca->beta);
+}
+
+static inline void measure_rtt(struct tcp_sock *tp)
+{
+ struct htcp *ca = tcp_ca(tp);
+ u32 srtt = tp->srtt>>3;
+
+ /* keep track of minimum RTT seen so far, minRTT is zero at first */
+ if (ca->minRTT > srtt || !ca->minRTT)
+ ca->minRTT = srtt;
+
+ /* max RTT */
+ if (tp->ca_state == TCP_CA_Open && tp->snd_ssthresh < 0xFFFF && ca->ccount > 3) {
+ if (ca->maxRTT < ca->minRTT)
+ ca->maxRTT = ca->minRTT;
+ if (ca->maxRTT < srtt && srtt <= ca->maxRTT+HZ/50)
+ ca->maxRTT = srtt;
+ }
+}
+
+static void measure_achieved_throughput(struct tcp_sock *tp, u32 pkts_acked)
+{
+ struct htcp *ca = tcp_ca(tp);
+ u32 now = tcp_time_stamp;
+
+ /* achieved throughput calculations */
+ if (tp->ca_state != TCP_CA_Open && tp->ca_state != TCP_CA_Disorder) {
+ ca->packetcount = 0;
+ ca->lasttime = now;
+ return;
+ }
+
+ ca->packetcount += pkts_acked;
+
+ if (ca->packetcount >= tp->snd_cwnd - (ca->alpha>>7? : 1)
+ && now - ca->lasttime >= ca->minRTT
+ && ca->minRTT > 0) {
+ __u32 cur_Bi = ca->packetcount*HZ/(now - ca->lasttime);
+ if (ca->ccount <= 3) {
+ /* just after backoff */
+ ca->minB = ca->maxB = ca->Bi = cur_Bi;
+ } else {
+ ca->Bi = (3*ca->Bi + cur_Bi)/4;
+ if (ca->Bi > ca->maxB)
+ ca->maxB = ca->Bi;
+ if (ca->minB > ca->maxB)
+ ca->minB = ca->maxB;
+ }
+ ca->packetcount = 0;
+ ca->lasttime = now;
+ }
+}
+
+static inline void htcp_beta_update(struct htcp *ca, u32 minRTT, u32 maxRTT)
+{
+ if (use_bandwidth_switch) {
+ u32 maxB = ca->maxB;
+ u32 old_maxB = ca->old_maxB;
+ ca->old_maxB = ca->maxB;
+
+ if (!between(5*maxB, 4*old_maxB, 6*old_maxB)) {
+ ca->beta = BETA_MIN;
+ ca->modeswitch = 0;
+ return;
+ }
+ }
+
+ if (ca->modeswitch && minRTT > max(HZ/100, 1) && maxRTT) {
+ ca->beta = (minRTT<<7)/maxRTT;
+ if (ca->beta < BETA_MIN)
+ ca->beta = BETA_MIN;
+ else if (ca->beta > BETA_MAX)
+ ca->beta = BETA_MAX;
+ } else {
+ ca->beta = BETA_MIN;
+ ca->modeswitch = 1;
+ }
+}
+
+static inline void htcp_alpha_update(struct htcp *ca)
+{
+ u32 minRTT = ca->minRTT;
+ u32 factor = 1;
+ u32 diff = ca->ccount * minRTT; /* time since last backoff */
+
+ if (diff > HZ) {
+ diff -= HZ;
+ factor = 1+ ( 10*diff + ((diff/2)*(diff/2)/HZ) )/HZ;
+ }
+
+ if (use_rtt_scaling && minRTT) {
+ u32 scale = (HZ<<3)/(10*minRTT);
+ scale = min(max(scale, 1U<<2), 10U<<3); /* clamping ratio to interval [0.5,10]<<3 */
+ factor = (factor<<3)/scale;
+ if (!factor)
+ factor = 1;
+ }
+
+ ca->alpha = 2*factor*((1<<7)-ca->beta);
+ if (!ca->alpha)
+ ca->alpha = ALPHA_BASE;
+}
+
+/* After we have the rtt data to calculate beta, we'd still prefer to wait one
+ * rtt before we adjust our beta to ensure we are working from a consistent
+ * data.
+ *
+ * This function should be called when we hit a congestion event since only at
+ * that point do we really have a real sense of maxRTT (the queues en route
+ * were getting just too full now).
+ */
+static void htcp_param_update(struct tcp_sock *tp)
+{
+ struct htcp *ca = tcp_ca(tp);
+ u32 minRTT = ca->minRTT;
+ u32 maxRTT = ca->maxRTT;
+
+ htcp_beta_update(ca, minRTT, maxRTT);
+ htcp_alpha_update(ca);
+
+ /* add slowly fading memory for maxRTT to accommodate routing changes etc */
+ if (minRTT > 0 && maxRTT > minRTT)
+ ca->maxRTT = minRTT + ((maxRTT-minRTT)*95)/100;
+}
+
+static u32 htcp_recalc_ssthresh(struct tcp_sock *tp)
+{
+ struct htcp *ca = tcp_ca(tp);
+ htcp_param_update(tp);
+ return max((tp->snd_cwnd * ca->beta) >> 7, 2U);
+}
+
+static void htcp_cong_avoid(struct tcp_sock *tp, u32 ack, u32 rtt,
+ u32 in_flight, int data_acked)
+{
+ struct htcp *ca = tcp_ca(tp);
+
+ if (in_flight < tp->snd_cwnd)
+ return;
+
+ if (tp->snd_cwnd <= tp->snd_ssthresh) {
+ /* In "safe" area, increase. */
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ tp->snd_cwnd++;
+ } else {
+ measure_rtt(tp);
+
+ /* keep track of number of round-trip times since last backoff event */
+ if (ca->snd_cwnd_cnt2++ > tp->snd_cwnd) {
+ ca->ccount++;
+ ca->snd_cwnd_cnt2 = 0;
+ htcp_alpha_update(ca);
+ }
+
+ /* In dangerous area, increase slowly.
+ * In theory this is tp->snd_cwnd += alpha / tp->snd_cwnd
+ */
+ if ((tp->snd_cwnd_cnt++ * ca->alpha)>>7 >= tp->snd_cwnd) {
+ if (tp->snd_cwnd < tp->snd_cwnd_clamp)
+ tp->snd_cwnd++;
+ tp->snd_cwnd_cnt = 0;
+ ca->ccount++;
+ }
+ }
+}
+
+/* Lower bound on congestion window. */
+static u32 htcp_min_cwnd(struct tcp_sock *tp)
+{
+ return tp->snd_ssthresh;
+}
+
+
+static void htcp_init(struct tcp_sock *tp)
+{
+ struct htcp *ca = tcp_ca(tp);
+
+ memset(ca, 0, sizeof(struct htcp));
+ ca->alpha = ALPHA_BASE;
+ ca->beta = BETA_MIN;
+}
+
+static void htcp_state(struct tcp_sock *tp, u8 new_state)
+{
+ switch (new_state) {
+ case TCP_CA_CWR:
+ case TCP_CA_Recovery:
+ case TCP_CA_Loss:
+ htcp_reset(tcp_ca(tp));
+ break;
+ }
+}
+
+static struct tcp_congestion_ops htcp = {
+ .init = htcp_init,
+ .ssthresh = htcp_recalc_ssthresh,
+ .min_cwnd = htcp_min_cwnd,
+ .cong_avoid = htcp_cong_avoid,
+ .set_state = htcp_state,
+ .undo_cwnd = htcp_cwnd_undo,
+ .pkts_acked = measure_achieved_throughput,
+ .owner = THIS_MODULE,
+ .name = "htcp",
+};
+
+static int __init htcp_register(void)
+{
+ BUG_ON(sizeof(struct htcp) > TCP_CA_PRIV_SIZE);
+ BUILD_BUG_ON(BETA_MIN >= BETA_MAX);
+ if (!use_bandwidth_switch)
+ htcp.pkts_acked = NULL;
+ return tcp_register_congestion_control(&htcp);
+}
+
+static void __exit htcp_unregister(void)
+{
+ tcp_unregister_congestion_control(&htcp);
+}
+
+module_init(htcp_register);
+module_exit(htcp_unregister);
+
+MODULE_AUTHOR("Baruch Even");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("H-TCP");
diff --git a/net/ipv4/tcp_hybla.c b/net/ipv4/tcp_hybla.c
new file mode 100644
index 0000000000000000000000000000000000000000..13a66342c304d57db6f2b74fa6dbf04882a8eb2f
--- /dev/null
+++ b/net/ipv4/tcp_hybla.c
@@ -0,0 +1,187 @@
+/*
+ * TCP HYBLA
+ *
+ * TCP-HYBLA Congestion control algorithm, based on:
+ * C.Caini, R.Firrincieli, "TCP-Hybla: A TCP Enhancement
+ * for Heterogeneous Networks",
+ * International Journal on satellite Communications,
+ * September 2004
+ * Daniele Lacamera
+ * root at danielinux.net
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <net/tcp.h>
+
+/* Tcp Hybla structure. */
+struct hybla {
+ u8 hybla_en;
+ u32 snd_cwnd_cents; /* Keeps increment values when it is <1, <<7 */
+ u32 rho; /* Rho parameter, integer part */
+ u32 rho2; /* Rho * Rho, integer part */
+ u32 rho_3ls; /* Rho parameter, <<3 */
+ u32 rho2_7ls; /* Rho^2, <<7 */
+ u32 minrtt; /* Minimum smoothed round trip time value seen */
+};
+
+/* Hybla reference round trip time (default= 1/40 sec = 25 ms),
+ expressed in jiffies */
+static int rtt0 = 25;
+module_param(rtt0, int, 0644);
+MODULE_PARM_DESC(rtt0, "reference rout trip time (ms)");
+
+
+/* This is called to refresh values for hybla parameters */
+static inline void hybla_recalc_param (struct tcp_sock *tp)
+{
+ struct hybla *ca = tcp_ca(tp);
+
+ ca->rho_3ls = max_t(u32, tp->srtt / msecs_to_jiffies(rtt0), 8);
+ ca->rho = ca->rho_3ls >> 3;
+ ca->rho2_7ls = (ca->rho_3ls * ca->rho_3ls) << 1;
+ ca->rho2 = ca->rho2_7ls >>7;
+}
+
+static void hybla_init(struct tcp_sock *tp)
+{
+ struct hybla *ca = tcp_ca(tp);
+
+ ca->rho = 0;
+ ca->rho2 = 0;
+ ca->rho_3ls = 0;
+ ca->rho2_7ls = 0;
+ ca->snd_cwnd_cents = 0;
+ ca->hybla_en = 1;
+ tp->snd_cwnd = 2;
+ tp->snd_cwnd_clamp = 65535;
+
+ /* 1st Rho measurement based on initial srtt */
+ hybla_recalc_param(tp);
+
+ /* set minimum rtt as this is the 1st ever seen */
+ ca->minrtt = tp->srtt;
+ tp->snd_cwnd = ca->rho;
+}
+
+static void hybla_state(struct tcp_sock *tp, u8 ca_state)
+{
+ struct hybla *ca = tcp_ca(tp);
+
+ ca->hybla_en = (ca_state == TCP_CA_Open);
+}
+
+static inline u32 hybla_fraction(u32 odds)
+{
+ static const u32 fractions[] = {
+ 128, 139, 152, 165, 181, 197, 215, 234,
+ };
+
+ return (odds < ARRAY_SIZE(fractions)) ? fractions[odds] : 128;
+}
+
+/* TCP Hybla main routine.
+ * This is the algorithm behavior:
+ * o Recalc Hybla parameters if min_rtt has changed
+ * o Give cwnd a new value based on the model proposed
+ * o remember increments <1
+ */
+static void hybla_cong_avoid(struct tcp_sock *tp, u32 ack, u32 rtt,
+ u32 in_flight, int flag)
+{
+ struct hybla *ca = tcp_ca(tp);
+ u32 increment, odd, rho_fractions;
+ int is_slowstart = 0;
+
+ /* Recalculate rho only if this srtt is the lowest */
+ if (tp->srtt < ca->minrtt){
+ hybla_recalc_param(tp);
+ ca->minrtt = tp->srtt;
+ }
+
+ if (!ca->hybla_en)
+ return tcp_reno_cong_avoid(tp, ack, rtt, in_flight, flag);
+
+ if (in_flight < tp->snd_cwnd)
+ return;
+
+ if (ca->rho == 0)
+ hybla_recalc_param(tp);
+
+ rho_fractions = ca->rho_3ls - (ca->rho << 3);
+
+ if (tp->snd_cwnd < tp->snd_ssthresh) {
+ /*
+ * slow start
+ * INC = 2^RHO - 1
+ * This is done by splitting the rho parameter
+ * into 2 parts: an integer part and a fraction part.
+ * Inrement<<7 is estimated by doing:
+ * [2^(int+fract)]<<7
+ * that is equal to:
+ * (2^int) * [(2^fract) <<7]
+ * 2^int is straightly computed as 1<<int,
+ * while we will use hybla_slowstart_fraction_increment() to
+ * calculate 2^fract in a <<7 value.
+ */
+ is_slowstart = 1;
+ increment = ((1 << ca->rho) * hybla_fraction(rho_fractions))
+ - 128;
+ } else {
+ /*
+ * congestion avoidance
+ * INC = RHO^2 / W
+ * as long as increment is estimated as (rho<<7)/window
+ * it already is <<7 and we can easily count its fractions.
+ */
+ increment = ca->rho2_7ls / tp->snd_cwnd;
+ if (increment < 128)
+ tp->snd_cwnd_cnt++;
+ }
+
+ odd = increment % 128;
+ tp->snd_cwnd += increment >> 7;
+ ca->snd_cwnd_cents += odd;
+
+ /* check when fractions goes >=128 and increase cwnd by 1. */
+ while(ca->snd_cwnd_cents >= 128) {
+ tp->snd_cwnd++;
+ ca->snd_cwnd_cents -= 128;
+ tp->snd_cwnd_cnt = 0;
+ }
+
+ /* clamp down slowstart cwnd to ssthresh value. */
+ if (is_slowstart)
+ tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
+
+ tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp);
+}
+
+static struct tcp_congestion_ops tcp_hybla = {
+ .init = hybla_init,
+ .ssthresh = tcp_reno_ssthresh,
+ .min_cwnd = tcp_reno_min_cwnd,
+ .cong_avoid = hybla_cong_avoid,
+ .set_state = hybla_state,
+
+ .owner = THIS_MODULE,
+ .name = "hybla"
+};
+
+static int __init hybla_register(void)
+{
+ BUG_ON(sizeof(struct hybla) > TCP_CA_PRIV_SIZE);
+ return tcp_register_congestion_control(&tcp_hybla);
+}
+
+static void __exit hybla_unregister(void)
+{
+ tcp_unregister_congestion_control(&tcp_hybla);
+}
+
+module_init(hybla_register);
+module_exit(hybla_unregister);
+
+MODULE_AUTHOR("Daniele Lacamera");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("TCP Hybla");
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 5bad504630a3b641158af85f402cc91da27e4d06..7bbbbc33eb4bf91527a8685d327b62009938c00f 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -61,7 +61,6 @@
* Panu Kuhlberg: Experimental audit of TCP (re)transmission
* engine. Lots of bugs are found.
* Pasi Sarolahti: F-RTO for dealing with spurious RTOs
- * Angelo Dell'Aera: TCP Westwood+ support
*/
#include <linux/config.h>
@@ -88,23 +87,9 @@ int sysctl_tcp_rfc1337;
int sysctl_tcp_max_orphans = NR_FILE;
int sysctl_tcp_frto;
int sysctl_tcp_nometrics_save;
-int sysctl_tcp_westwood;
-int sysctl_tcp_vegas_cong_avoid;
int sysctl_tcp_moderate_rcvbuf = 1;
-/* Default values of the Vegas variables, in fixed-point representation
- * with V_PARAM_SHIFT bits to the right of the binary point.
- */
-#define V_PARAM_SHIFT 1
-int sysctl_tcp_vegas_alpha = 1<<V_PARAM_SHIFT;
-int sysctl_tcp_vegas_beta = 3<<V_PARAM_SHIFT;
-int sysctl_tcp_vegas_gamma = 1<<V_PARAM_SHIFT;
-int sysctl_tcp_bic = 1;
-int sysctl_tcp_bic_fast_convergence = 1;
-int sysctl_tcp_bic_low_window = 14;
-int sysctl_tcp_bic_beta = 819; /* = 819/1024 (BICTCP_BETA_SCALE) */
-
#define FLAG_DATA 0x01 /* Incoming frame contained data. */
#define FLAG_WIN_UPDATE 0x02 /* Incoming ACK was a window update. */
#define FLAG_DATA_ACKED 0x04 /* This ACK acknowledged new data. */
@@ -333,15 +318,6 @@ static void tcp_init_buffer_space(struct sock *sk)
tp->snd_cwnd_stamp = tcp_time_stamp;
}
-static void init_bictcp(struct tcp_sock *tp)
-{
- tp->bictcp.cnt = 0;
-
- tp->bictcp.last_max_cwnd = 0;
- tp->bictcp.last_cwnd = 0;
- tp->bictcp.last_stamp = 0;
-}
-
/* 5. Recalculate window clamp after socket hit its memory bounds. */
static void tcp_clamp_window(struct sock *sk, struct tcp_sock *tp)
{
@@ -558,45 +534,6 @@ static void tcp_event_data_recv(struct sock *sk, struct tcp_sock *tp, struct sk_
tcp_grow_window(sk, tp, skb);
}
-/* When starting a new connection, pin down the current choice of
- * congestion algorithm.
- */
-void tcp_ca_init(struct tcp_sock *tp)
-{
- if (sysctl_tcp_westwood)
- tp->adv_cong = TCP_WESTWOOD;
- else if (sysctl_tcp_bic)
- tp->adv_cong = TCP_BIC;
- else if (sysctl_tcp_vegas_cong_avoid) {
- tp->adv_cong = TCP_VEGAS;
- tp->vegas.baseRTT = 0x7fffffff;
- tcp_vegas_enable(tp);
- }
-}
-
-/* Do RTT sampling needed for Vegas.
- * Basically we:
- * o min-filter RTT samples from within an RTT to get the current
- * propagation delay + queuing delay (we are min-filtering to try to
- * avoid the effects of delayed ACKs)
- * o min-filter RTT samples from a much longer window (forever for now)
- * to find the propagation delay (baseRTT)
- */
-static inline void vegas_rtt_calc(struct tcp_sock *tp, __u32 rtt)
-{
- __u32 vrtt = rtt + 1; /* Never allow zero rtt or baseRTT */
-
- /* Filter to find propagation delay: */
- if (vrtt < tp->vegas.baseRTT)
- tp->vegas.baseRTT = vrtt;
-
- /* Find the min RTT during the last RTT to find
- * the current prop. delay + queuing delay:
- */
- tp->vegas.minRTT = min(tp->vegas.minRTT, vrtt);
- tp->vegas.cntRTT++;
-}
-
/* Called to compute a smoothed rtt estimate. The data fed to this
* routine either comes from timestamps, or from segments that were
* known _not_ to have been retransmitted [see Karn/Partridge
@@ -606,13 +543,10 @@ static inline void vegas_rtt_calc(struct tcp_sock *tp, __u32 rtt)
* To save cycles in the RFC 1323 implementation it was better to break
* it up into three procedures. -- erics
*/
-static void tcp_rtt_estimator(struct tcp_sock *tp, __u32 mrtt)
+static void tcp_rtt_estimator(struct tcp_sock *tp, __u32 mrtt, u32 *usrtt)
{
long m = mrtt; /* RTT */
- if (tcp_vegas_enabled(tp))
- vegas_rtt_calc(tp, mrtt);
-
/* The following amusing code comes from Jacobson's
* article in SIGCOMM '88. Note that rtt and mdev
* are scaled versions of rtt and mean deviation.
@@ -670,7 +604,8 @@ static void tcp_rtt_estimator(struct tcp_sock *tp, __u32 mrtt)
tp->rtt_seq = tp->snd_nxt;
}
- tcp_westwood_update_rtt(tp, tp->srtt >> 3);
+ if (tp->ca_ops->rtt_sample)
+ tp->ca_ops->rtt_sample(tp, *usrtt);
}
/* Calculate rto without backoff. This is the second half of Van Jacobson's
@@ -1185,8 +1120,8 @@ void tcp_enter_frto(struct sock *sk)
tp->snd_una == tp->high_seq ||
(tp->ca_state == TCP_CA_Loss && !tp->retransmits)) {
tp->prior_ssthresh = tcp_current_ssthresh(tp);
- if (!tcp_westwood_ssthresh(tp))
- tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
+ tp->snd_ssthresh = tp->ca_ops->ssthresh(tp);
+ tcp_ca_event(tp, CA_EVENT_FRTO);
}
/* Have to clear retransmission markers here to keep the bookkeeping
@@ -1252,8 +1187,6 @@ static void tcp_enter_frto_loss(struct sock *sk)
tcp_set_ca_state(tp, TCP_CA_Loss);
tp->high_seq = tp->frto_highmark;
TCP_ECN_queue_cwr(tp);
-
- init_bictcp(tp);
}
void tcp_clear_retrans(struct tcp_sock *tp)
@@ -1283,7 +1216,8 @@ void tcp_enter_loss(struct sock *sk, int how)
if (tp->ca_state <= TCP_CA_Disorder || tp->snd_una == tp->high_seq ||
(tp->ca_state == TCP_CA_Loss && !tp->retransmits)) {
tp->prior_ssthresh = tcp_current_ssthresh(tp);
- tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
+ tp->snd_ssthresh = tp->ca_ops->ssthresh(tp);
+ tcp_ca_event(tp, CA_EVENT_LOSS);
}
tp->snd_cwnd = 1;
tp->snd_cwnd_cnt = 0;
@@ -1596,28 +1530,14 @@ static inline void tcp_moderate_cwnd(struct tcp_sock *tp)
}
/* Decrease cwnd each second ack. */
-
static void tcp_cwnd_down(struct tcp_sock *tp)
{
int decr = tp->snd_cwnd_cnt + 1;
- __u32 limit;
-
- /*
- * TCP Westwood
- * Here limit is evaluated as BWestimation*RTTmin (for obtaining it
- * in packets we use mss_cache). If sysctl_tcp_westwood is off
- * tcp_westwood_bw_rttmin() returns 0. In such case snd_ssthresh is
- * still used as usual. It prevents other strange cases in which
- * BWE*RTTmin could assume value 0. It should not happen but...
- */
-
- if (!(limit = tcp_westwood_bw_rttmin(tp)))
- limit = tp->snd_ssthresh/2;
tp->snd_cwnd_cnt = decr&1;
decr >>= 1;
- if (decr && tp->snd_cwnd > limit)
+ if (decr && tp->snd_cwnd > tp->ca_ops->min_cwnd(tp))
tp->snd_cwnd -= decr;
tp->snd_cwnd = min(tp->snd_cwnd, tcp_packets_in_flight(tp)+1);
@@ -1654,8 +1574,8 @@ static void DBGUNDO(struct sock *sk, struct tcp_sock *tp, const char *msg)
static void tcp_undo_cwr(struct tcp_sock *tp, int undo)
{
if (tp->prior_ssthresh) {
- if (tcp_is_bic(tp))
- tp->snd_cwnd = max(tp->snd_cwnd, tp->bictcp.last_max_cwnd);
+ if (tp->ca_ops->undo_cwnd)
+ tp->snd_cwnd = tp->ca_ops->undo_cwnd(tp);
else
tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh<<1);
@@ -1767,11 +1687,9 @@ static int tcp_try_undo_loss(struct sock *sk, struct tcp_sock *tp)
static inline void tcp_complete_cwr(struct tcp_sock *tp)
{
- if (tcp_westwood_cwnd(tp))
- tp->snd_ssthresh = tp->snd_cwnd;
- else
- tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
+ tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
tp->snd_cwnd_stamp = tcp_time_stamp;
+ tcp_ca_event(tp, CA_EVENT_COMPLETE_CWR);
}
static void tcp_try_to_open(struct sock *sk, struct tcp_sock *tp, int flag)
@@ -1946,7 +1864,7 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
if (tp->ca_state < TCP_CA_CWR) {
if (!(flag&FLAG_ECE))
tp->prior_ssthresh = tcp_current_ssthresh(tp);
- tp->snd_ssthresh = tcp_recalc_ssthresh(tp);
+ tp->snd_ssthresh = tp->ca_ops->ssthresh(tp);
TCP_ECN_queue_cwr(tp);
}
@@ -1963,7 +1881,7 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una,
/* Read draft-ietf-tcplw-high-performance before mucking
* with this code. (Superceeds RFC1323)
*/
-static void tcp_ack_saw_tstamp(struct tcp_sock *tp, int flag)
+static void tcp_ack_saw_tstamp(struct tcp_sock *tp, u32 *usrtt, int flag)
{
__u32 seq_rtt;
@@ -1983,13 +1901,13 @@ static void tcp_ack_saw_tstamp(struct tcp_sock *tp, int flag)
* in window is lost... Voila. --ANK (010210)
*/
seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
- tcp_rtt_estimator(tp, seq_rtt);
+ tcp_rtt_estimator(tp, seq_rtt, usrtt);
tcp_set_rto(tp);
tp->backoff = 0;
tcp_bound_rto(tp);
}
-static void tcp_ack_no_tstamp(struct tcp_sock *tp, u32 seq_rtt, int flag)
+static void tcp_ack_no_tstamp(struct tcp_sock *tp, u32 seq_rtt, u32 *usrtt, int flag)
{
/* We don't have a timestamp. Can only use
* packets that are not retransmitted to determine
@@ -2003,338 +1921,29 @@ static void tcp_ack_no_tstamp(struct tcp_sock *tp, u32 seq_rtt, int flag)
if (flag & FLAG_RETRANS_DATA_ACKED)
return;
- tcp_rtt_estimator(tp, seq_rtt);
+ tcp_rtt_estimator(tp, seq_rtt, usrtt);
tcp_set_rto(tp);
tp->backoff = 0;
tcp_bound_rto(tp);
}
static inline void tcp_ack_update_rtt(struct tcp_sock *tp,
- int flag, s32 seq_rtt)
+ int flag, s32 seq_rtt, u32 *usrtt)
{
/* Note that peer MAY send zero echo. In this case it is ignored. (rfc1323) */
if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
- tcp_ack_saw_tstamp(tp, flag);
+ tcp_ack_saw_tstamp(tp, usrtt, flag);
else if (seq_rtt >= 0)
- tcp_ack_no_tstamp(tp, seq_rtt, flag);
+ tcp_ack_no_tstamp(tp, seq_rtt, usrtt, flag);
}
-/*
- * Compute congestion window to use.
- *
- * This is from the implementation of BICTCP in
- * Lison-Xu, Kahaled Harfoush, and Injog Rhee.
- * "Binary Increase Congestion Control for Fast, Long Distance
- * Networks" in InfoComm 2004
- * Available from:
- * http://www.csc.ncsu.edu/faculty/rhee/export/bitcp.pdf
- *
- * Unless BIC is enabled and congestion window is large
- * this behaves the same as the original Reno.
- */
-static inline __u32 bictcp_cwnd(struct tcp_sock *tp)
-{
- /* orignal Reno behaviour */
- if (!tcp_is_bic(tp))
- return tp->snd_cwnd;
-
- if (tp->bictcp.last_cwnd == tp->snd_cwnd &&
- (s32)(tcp_time_stamp - tp->bictcp.last_stamp) <= (HZ>>5))
- return tp->bictcp.cnt;
-
- tp->bictcp.last_cwnd = tp->snd_cwnd;
- tp->bictcp.last_stamp = tcp_time_stamp;
-
- /* start off normal */
- if (tp->snd_cwnd <= sysctl_tcp_bic_low_window)
- tp->bictcp.cnt = tp->snd_cwnd;
-
- /* binary increase */
- else if (tp->snd_cwnd < tp->bictcp.last_max_cwnd) {
- __u32 dist = (tp->bictcp.last_max_cwnd - tp->snd_cwnd)
- / BICTCP_B;
-
- if (dist > BICTCP_MAX_INCREMENT)
- /* linear increase */
- tp->bictcp.cnt = tp->snd_cwnd / BICTCP_MAX_INCREMENT;
- else if (dist <= 1U)
- /* binary search increase */
- tp->bictcp.cnt = tp->snd_cwnd * BICTCP_FUNC_OF_MIN_INCR
- / BICTCP_B;
- else
- /* binary search increase */
- tp->bictcp.cnt = tp->snd_cwnd / dist;
- } else {
- /* slow start amd linear increase */
- if (tp->snd_cwnd < tp->bictcp.last_max_cwnd + BICTCP_B)
- /* slow start */
- tp->bictcp.cnt = tp->snd_cwnd * BICTCP_FUNC_OF_MIN_INCR
- / BICTCP_B;
- else if (tp->snd_cwnd < tp->bictcp.last_max_cwnd
- + BICTCP_MAX_INCREMENT*(BICTCP_B-1))
- /* slow start */
- tp->bictcp.cnt = tp->snd_cwnd * (BICTCP_B-1)
- / (tp->snd_cwnd-tp->bictcp.last_max_cwnd);
- else
- /* linear increase */
- tp->bictcp.cnt = tp->snd_cwnd / BICTCP_MAX_INCREMENT;
- }
- return tp->bictcp.cnt;
-}
-
-/* This is Jacobson's slow start and congestion avoidance.
- * SIGCOMM '88, p. 328.
- */
-static inline void reno_cong_avoid(struct tcp_sock *tp)
+static inline void tcp_cong_avoid(struct tcp_sock *tp, u32 ack, u32 rtt,
+ u32 in_flight, int good)
{
- if (tp->snd_cwnd <= tp->snd_ssthresh) {
- /* In "safe" area, increase. */
- if (tp->snd_cwnd < tp->snd_cwnd_clamp)
- tp->snd_cwnd++;
- } else {
- /* In dangerous area, increase slowly.
- * In theory this is tp->snd_cwnd += 1 / tp->snd_cwnd
- */
- if (tp->snd_cwnd_cnt >= bictcp_cwnd(tp)) {
- if (tp->snd_cwnd < tp->snd_cwnd_clamp)
- tp->snd_cwnd++;
- tp->snd_cwnd_cnt=0;
- } else
- tp->snd_cwnd_cnt++;
- }
+ tp->ca_ops->cong_avoid(tp, ack, rtt, in_flight, good);
tp->snd_cwnd_stamp = tcp_time_stamp;
}
-/* This is based on the congestion detection/avoidance scheme described in
- * Lawrence S. Brakmo and Larry L. Peterson.
- * "TCP Vegas: End to end congestion avoidance on a global internet."
- * IEEE Journal on Selected Areas in Communication, 13(8):1465--1480,
- * October 1995. Available from:
- * ftp://ftp.cs.arizona.edu/xkernel/Papers/jsac.ps
- *
- * See http://www.cs.arizona.edu/xkernel/ for their implementation.
- * The main aspects that distinguish this implementation from the
- * Arizona Vegas implementation are:
- * o We do not change the loss detection or recovery mechanisms of
- * Linux in any way. Linux already recovers from losses quite well,
- * using fine-grained timers, NewReno, and FACK.
- * o To avoid the performance penalty imposed by increasing cwnd
- * only every-other RTT during slow start, we increase during
- * every RTT during slow start, just like Reno.
- * o Largely to allow continuous cwnd growth during slow start,
- * we use the rate at which ACKs come back as the "actual"
- * rate, rather than the rate at which data is sent.
- * o To speed convergence to the right rate, we set the cwnd
- * to achieve the right ("actual") rate when we exit slow start.
- * o To filter out the noise caused by delayed ACKs, we use the
- * minimum RTT sample observed during the last RTT to calculate
- * the actual rate.
- * o When the sender re-starts from idle, it waits until it has
- * received ACKs for an entire flight of new data before making
- * a cwnd adjustment decision. The original Vegas implementation
- * assumed senders never went idle.
- */
-static void vegas_cong_avoid(struct tcp_sock *tp, u32 ack, u32 seq_rtt)
-{
- /* The key players are v_beg_snd_una and v_beg_snd_nxt.
- *
- * These are so named because they represent the approximate values
- * of snd_una and snd_nxt at the beginning of the current RTT. More
- * precisely, they represent the amount of data sent during the RTT.
- * At the end of the RTT, when we receive an ACK for v_beg_snd_nxt,
- * we will calculate that (v_beg_snd_nxt - v_beg_snd_una) outstanding
- * bytes of data have been ACKed during the course of the RTT, giving
- * an "actual" rate of:
- *
- * (v_beg_snd_nxt - v_beg_snd_una) / (rtt duration)
- *
- * Unfortunately, v_beg_snd_una is not exactly equal to snd_una,
- * because delayed ACKs can cover more than one segment, so they
- * don't line up nicely with the boundaries of RTTs.
- *
- * Another unfortunate fact of life is that delayed ACKs delay the
- * advance of the left edge of our send window, so that the number
- * of bytes we send in an RTT is often less than our cwnd will allow.
- * So we keep track of our cwnd separately, in v_beg_snd_cwnd.
- */
-
- if (after(ack, tp->vegas.beg_snd_nxt)) {
- /* Do the Vegas once-per-RTT cwnd adjustment. */
- u32 old_wnd, old_snd_cwnd;
-
-
- /* Here old_wnd is essentially the window of data that was
- * sent during the previous RTT, and has all
- * been acknowledged in the course of the RTT that ended
- * with the ACK we just received. Likewise, old_snd_cwnd
- * is the cwnd during the previous RTT.
- */
- old_wnd = (tp->vegas.beg_snd_nxt - tp->vegas.beg_snd_una) /
- tp->mss_cache_std;
- old_snd_cwnd = tp->vegas.beg_snd_cwnd;
-
- /* Save the extent of the current window so we can use this
- * at the end of the next RTT.
- */
- tp->vegas.beg_snd_una = tp->vegas.beg_snd_nxt;
- tp->vegas.beg_snd_nxt = tp->snd_nxt;
- tp->vegas.beg_snd_cwnd = tp->snd_cwnd;
-
- /* Take into account the current RTT sample too, to
- * decrease the impact of delayed acks. This double counts
- * this sample since we count it for the next window as well,
- * but that's not too awful, since we're taking the min,
- * rather than averaging.
- */
- vegas_rtt_calc(tp, seq_rtt);
-
- /* We do the Vegas calculations only if we got enough RTT
- * samples that we can be reasonably sure that we got
- * at least one RTT sample that wasn't from a delayed ACK.
- * If we only had 2 samples total,
- * then that means we're getting only 1 ACK per RTT, which
- * means they're almost certainly delayed ACKs.
- * If we have 3 samples, we should be OK.
- */
-
- if (tp->vegas.cntRTT <= 2) {
- /* We don't have enough RTT samples to do the Vegas
- * calculation, so we'll behave like Reno.
- */
- if (tp->snd_cwnd > tp->snd_ssthresh)
- tp->snd_cwnd++;
- } else {
- u32 rtt, target_cwnd, diff;
-
- /* We have enough RTT samples, so, using the Vegas
- * algorithm, we determine if we should increase or
- * decrease cwnd, and by how much.
- */
-
- /* Pluck out the RTT we are using for the Vegas
- * calculations. This is the min RTT seen during the
- * last RTT. Taking the min filters out the effects
- * of delayed ACKs, at the cost of noticing congestion
- * a bit later.
- */
- rtt = tp->vegas.minRTT;
-
- /* Calculate the cwnd we should have, if we weren't
- * going too fast.
- *
- * This is:
- * (actual rate in segments) * baseRTT
- * We keep it as a fixed point number with
- * V_PARAM_SHIFT bits to the right of the binary point.
- */
- target_cwnd = ((old_wnd * tp->vegas.baseRTT)
- << V_PARAM_SHIFT) / rtt;
-
- /* Calculate the difference between the window we had,
- * and the window we would like to have. This quantity
- * is the "Diff" from the Arizona Vegas papers.
- *
- * Again, this is a fixed point number with
- * V_PARAM_SHIFT bits to the right of the binary
- * point.
- */
- diff = (old_wnd << V_PARAM_SHIFT) - target_cwnd;
-
- if (tp->snd_cwnd < tp->snd_ssthresh) {
- /* Slow start. */
- if (diff > sysctl_tcp_vegas_gamma) {
- /* Going too fast. Time to slow down
- * and switch to congestion avoidance.
- */
- tp->snd_ssthresh = 2;
-
- /* Set cwnd to match the actual rate
- * exactly:
- * cwnd = (actual rate) * baseRTT
- * Then we add 1 because the integer
- * truncation robs us of full link
- * utilization.
- */
- tp->snd_cwnd = min(tp->snd_cwnd,
- (target_cwnd >>
- V_PARAM_SHIFT)+1);
-
- }
- } else {
- /* Congestion avoidance. */
- u32 next_snd_cwnd;
-
- /* Figure out where we would like cwnd
- * to be.
- */
- if (diff > sysctl_tcp_vegas_beta) {
- /* The old window was too fast, so
- * we slow down.
- */
- next_snd_cwnd = old_snd_cwnd - 1;
- } else if (diff < sysctl_tcp_vegas_alpha) {
- /* We don't have enough extra packets
- * in the network, so speed up.
- */
- next_snd_cwnd = old_snd_cwnd + 1;
- } else {
- /* Sending just as fast as we
- * should be.
- */
- next_snd_cwnd = old_snd_cwnd;
- }
-
- /* Adjust cwnd upward or downward, toward the
- * desired value.
- */
- if (next_snd_cwnd > tp->snd_cwnd)
- tp->snd_cwnd++;
- else if (next_snd_cwnd < tp->snd_cwnd)
- tp->snd_cwnd--;
- }
- }
-
- /* Wipe the slate clean for the next RTT. */
- tp->vegas.cntRTT = 0;
- tp->vegas.minRTT = 0x7fffffff;
- }
-
- /* The following code is executed for every ack we receive,
- * except for conditions checked in should_advance_cwnd()
- * before the call to tcp_cong_avoid(). Mainly this means that
- * we only execute this code if the ack actually acked some
- * data.
- */
-
- /* If we are in slow start, increase our cwnd in response to this ACK.
- * (If we are not in slow start then we are in congestion avoidance,
- * and adjust our congestion window only once per RTT. See the code
- * above.)
- */
- if (tp->snd_cwnd <= tp->snd_ssthresh)
- tp->snd_cwnd++;
-
- /* to keep cwnd from growing without bound */
- tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp);
-
- /* Make sure that we are never so timid as to reduce our cwnd below
- * 2 MSS.
- *
- * Going below 2 MSS would risk huge delayed ACKs from our receiver.
- */
- tp->snd_cwnd = max(tp->snd_cwnd, 2U);
-
- tp->snd_cwnd_stamp = tcp_time_stamp;
-}
-
-static inline void tcp_cong_avoid(struct tcp_sock *tp, u32 ack, u32 seq_rtt)
-{
- if (tcp_vegas_enabled(tp))
- vegas_cong_avoid(tp, ack, seq_rtt);
- else
- reno_cong_avoid(tp);
-}
-
/* Restart timer after forward progress on connection.
* RFC2988 recommends to restart timer to now+rto.
*/
@@ -2415,13 +2024,18 @@ static int tcp_tso_acked(struct sock *sk, struct sk_buff *skb,
/* Remove acknowledged frames from the retransmission queue. */
-static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
+static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p, s32 *seq_usrtt)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
__u32 now = tcp_time_stamp;
int acked = 0;
__s32 seq_rtt = -1;
+ struct timeval usnow;
+ u32 pkts_acked = 0;
+
+ if (seq_usrtt)
+ do_gettimeofday(&usnow);
while ((skb = skb_peek(&sk->sk_write_queue)) &&
skb != sk->sk_send_head) {
@@ -2448,6 +2062,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
*/
if (!(scb->flags & TCPCB_FLAG_SYN)) {
acked |= FLAG_DATA_ACKED;
+ ++pkts_acked;
} else {
acked |= FLAG_SYN_ACKED;
tp->retrans_stamp = 0;
@@ -2461,6 +2076,10 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
seq_rtt = -1;
} else if (seq_rtt < 0)
seq_rtt = now - scb->when;
+ if (seq_usrtt)
+ *seq_usrtt = (usnow.tv_sec - skb->stamp.tv_sec) * 1000000
+ + (usnow.tv_usec - skb->stamp.tv_usec);
+
if (sacked & TCPCB_SACKED_ACKED)
tp->sacked_out -= tcp_skb_pcount(skb);
if (sacked & TCPCB_LOST)
@@ -2479,8 +2098,11 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
}
if (acked&FLAG_ACKED) {
- tcp_ack_update_rtt(tp, acked, seq_rtt);
+ tcp_ack_update_rtt(tp, acked, seq_rtt, seq_usrtt);
tcp_ack_packets_out(sk, tp);
+
+ if (tp->ca_ops->pkts_acked)
+ tp->ca_ops->pkts_acked(tp, pkts_acked);
}
#if FASTRETRANS_DEBUG > 0
@@ -2624,257 +2246,6 @@ static void tcp_process_frto(struct sock *sk, u32 prior_snd_una)
tp->frto_counter = (tp->frto_counter + 1) % 3;
}
-/*
- * TCP Westwood+
- */
-
-/*
- * @init_westwood
- * This function initializes fields used in TCP Westwood+. We can't
- * get no information about RTTmin at this time so we simply set it to
- * TCP_WESTWOOD_INIT_RTT. This value was chosen to be too conservative
- * since in this way we're sure it will be updated in a consistent
- * way as soon as possible. It will reasonably happen within the first
- * RTT period of the connection lifetime.
- */
-
-static void init_westwood(struct sock *sk)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- tp->westwood.bw_ns_est = 0;
- tp->westwood.bw_est = 0;
- tp->westwood.accounted = 0;
- tp->westwood.cumul_ack = 0;
- tp->westwood.rtt_win_sx = tcp_time_stamp;
- tp->westwood.rtt = TCP_WESTWOOD_INIT_RTT;
- tp->westwood.rtt_min = TCP_WESTWOOD_INIT_RTT;
- tp->westwood.snd_una = tp->snd_una;
-}
-
-/*
- * @westwood_do_filter
- * Low-pass filter. Implemented using constant coeffients.
- */
-
-static inline __u32 westwood_do_filter(__u32 a, __u32 b)
-{
- return (((7 * a) + b) >> 3);
-}
-
-static void westwood_filter(struct sock *sk, __u32 delta)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- tp->westwood.bw_ns_est =
- westwood_do_filter(tp->westwood.bw_ns_est,
- tp->westwood.bk / delta);
- tp->westwood.bw_est =
- westwood_do_filter(tp->westwood.bw_est,
- tp->westwood.bw_ns_est);
-}
-
-/*
- * @westwood_update_rttmin
- * It is used to update RTTmin. In this case we MUST NOT use
- * WESTWOOD_RTT_MIN minimum bound since we could be on a LAN!
- */
-
-static inline __u32 westwood_update_rttmin(const struct sock *sk)
-{
- const struct tcp_sock *tp = tcp_sk(sk);
- __u32 rttmin = tp->westwood.rtt_min;
-
- if (tp->westwood.rtt != 0 &&
- (tp->westwood.rtt < tp->westwood.rtt_min || !rttmin))
- rttmin = tp->westwood.rtt;
-
- return rttmin;
-}
-
-/*
- * @westwood_acked
- * Evaluate increases for dk.
- */
-
-static inline __u32 westwood_acked(const struct sock *sk)
-{
- const struct tcp_sock *tp = tcp_sk(sk);
-
- return tp->snd_una - tp->westwood.snd_una;
-}
-
-/*
- * @westwood_new_window
- * It evaluates if we are receiving data inside the same RTT window as
- * when we started.
- * Return value:
- * It returns 0 if we are still evaluating samples in the same RTT
- * window, 1 if the sample has to be considered in the next window.
- */
-
-static int westwood_new_window(const struct sock *sk)
-{
- const struct tcp_sock *tp = tcp_sk(sk);
- __u32 left_bound;
- __u32 rtt;
- int ret = 0;
-
- left_bound = tp->westwood.rtt_win_sx;
- rtt = max(tp->westwood.rtt, (u32) TCP_WESTWOOD_RTT_MIN);
-
- /*
- * A RTT-window has passed. Be careful since if RTT is less than
- * 50ms we don't filter but we continue 'building the sample'.
- * This minimum limit was choosen since an estimation on small
- * time intervals is better to avoid...
- * Obvioulsy on a LAN we reasonably will always have
- * right_bound = left_bound + WESTWOOD_RTT_MIN
- */
-
- if ((left_bound + rtt) < tcp_time_stamp)
- ret = 1;
-
- return ret;
-}
-
-/*
- * @westwood_update_window
- * It updates RTT evaluation window if it is the right moment to do
- * it. If so it calls filter for evaluating bandwidth.
- */
-
-static void __westwood_update_window(struct sock *sk, __u32 now)
-{
- struct tcp_sock *tp = tcp_sk(sk);
- __u32 delta = now - tp->westwood.rtt_win_sx;
-
- if (delta) {
- if (tp->westwood.rtt)
- westwood_filter(sk, delta);
-
- tp->westwood.bk = 0;
- tp->westwood.rtt_win_sx = tcp_time_stamp;
- }
-}
-
-
-static void westwood_update_window(struct sock *sk, __u32 now)
-{
- if (westwood_new_window(sk))
- __westwood_update_window(sk, now);
-}
-
-/*
- * @__tcp_westwood_fast_bw
- * It is called when we are in fast path. In particular it is called when
- * header prediction is successfull. In such case infact update is
- * straight forward and doesn't need any particular care.
- */
-
-static void __tcp_westwood_fast_bw(struct sock *sk, struct sk_buff *skb)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- westwood_update_window(sk, tcp_time_stamp);
-
- tp->westwood.bk += westwood_acked(sk);
- tp->westwood.snd_una = tp->snd_una;
- tp->westwood.rtt_min = westwood_update_rttmin(sk);
-}
-
-static inline void tcp_westwood_fast_bw(struct sock *sk, struct sk_buff *skb)
-{
- if (tcp_is_westwood(tcp_sk(sk)))
- __tcp_westwood_fast_bw(sk, skb);
-}
-
-
-/*
- * @westwood_dupack_update
- * It updates accounted and cumul_ack when receiving a dupack.
- */
-
-static void westwood_dupack_update(struct sock *sk)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- tp->westwood.accounted += tp->mss_cache_std;
- tp->westwood.cumul_ack = tp->mss_cache_std;
-}
-
-static inline int westwood_may_change_cumul(struct tcp_sock *tp)
-{
- return (tp->westwood.cumul_ack > tp->mss_cache_std);
-}
-
-static inline void westwood_partial_update(struct tcp_sock *tp)
-{
- tp->westwood.accounted -= tp->westwood.cumul_ack;
- tp->westwood.cumul_ack = tp->mss_cache_std;
-}
-
-static inline void westwood_complete_update(struct tcp_sock *tp)
-{
- tp->westwood.cumul_ack -= tp->westwood.accounted;
- tp->westwood.accounted = 0;
-}
-
-/*
- * @westwood_acked_count
- * This function evaluates cumul_ack for evaluating dk in case of
- * delayed or partial acks.
- */
-
-static inline __u32 westwood_acked_count(struct sock *sk)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- tp->westwood.cumul_ack = westwood_acked(sk);
-
- /* If cumul_ack is 0 this is a dupack since it's not moving
- * tp->snd_una.
- */
- if (!(tp->westwood.cumul_ack))
- westwood_dupack_update(sk);
-
- if (westwood_may_change_cumul(tp)) {
- /* Partial or delayed ack */
- if (tp->westwood.accounted >= tp->westwood.cumul_ack)
- westwood_partial_update(tp);
- else
- westwood_complete_update(tp);
- }
-
- tp->westwood.snd_una = tp->snd_una;
-
- return tp->westwood.cumul_ack;
-}
-
-
-/*
- * @__tcp_westwood_slow_bw
- * It is called when something is going wrong..even if there could
- * be no problems! Infact a simple delayed packet may trigger a
- * dupack. But we need to be careful in such case.
- */
-
-static void __tcp_westwood_slow_bw(struct sock *sk, struct sk_buff *skb)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- westwood_update_window(sk, tcp_time_stamp);
-
- tp->westwood.bk += westwood_acked_count(sk);
- tp->westwood.rtt_min = westwood_update_rttmin(sk);
-}
-
-static inline void tcp_westwood_slow_bw(struct sock *sk, struct sk_buff *skb)
-{
- if (tcp_is_westwood(tcp_sk(sk)))
- __tcp_westwood_slow_bw(sk, skb);
-}
-
/* This routine deals with incoming acks, but not outgoing ones. */
static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
{
@@ -2884,6 +2255,7 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
u32 ack = TCP_SKB_CB(skb)->ack_seq;
u32 prior_in_flight;
s32 seq_rtt;
+ s32 seq_usrtt = 0;
int prior_packets;
/* If the ack is newer than sent or older than previous acks
@@ -2902,9 +2274,10 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
*/
tcp_update_wl(tp, ack, ack_seq);
tp->snd_una = ack;
- tcp_westwood_fast_bw(sk, skb);
flag |= FLAG_WIN_UPDATE;
+ tcp_ca_event(tp, CA_EVENT_FAST_ACK);
+
NET_INC_STATS_BH(LINUX_MIB_TCPHPACKS);
} else {
if (ack_seq != TCP_SKB_CB(skb)->end_seq)
@@ -2920,7 +2293,7 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
if (TCP_ECN_rcv_ecn_echo(tp, skb->h.th))
flag |= FLAG_ECE;
- tcp_westwood_slow_bw(sk,skb);
+ tcp_ca_event(tp, CA_EVENT_SLOW_ACK);
}
/* We passed data and got it acked, remove any soft error
@@ -2935,22 +2308,20 @@ static int tcp_ack(struct sock *sk, struct sk_buff *skb, int flag)
prior_in_flight = tcp_packets_in_flight(tp);
/* See if we can take anything off of the retransmit queue. */
- flag |= tcp_clean_rtx_queue(sk, &seq_rtt);
+ flag |= tcp_clean_rtx_queue(sk, &seq_rtt,
+ tp->ca_ops->rtt_sample ? &seq_usrtt : NULL);
if (tp->frto_counter)
tcp_process_frto(sk, prior_snd_una);
if (tcp_ack_is_dubious(tp, flag)) {
/* Advanve CWND, if state allows this. */
- if ((flag & FLAG_DATA_ACKED) &&
- (tcp_vegas_enabled(tp) || prior_in_flight >= tp->snd_cwnd) &&
- tcp_may_raise_cwnd(tp, flag))
- tcp_cong_avoid(tp, ack, seq_rtt);
+ if ((flag & FLAG_DATA_ACKED) && tcp_may_raise_cwnd(tp, flag))
+ tcp_cong_avoid(tp, ack, seq_rtt, prior_in_flight, 0);
tcp_fastretrans_alert(sk, prior_snd_una, prior_packets, flag);
} else {
- if ((flag & FLAG_DATA_ACKED) &&
- (tcp_vegas_enabled(tp) || prior_in_flight >= tp->snd_cwnd))
- tcp_cong_avoid(tp, ack, seq_rtt);
+ if ((flag & FLAG_DATA_ACKED))
+ tcp_cong_avoid(tp, ack, seq_rtt, prior_in_flight, 1);
}
if ((flag & FLAG_FORWARD_PROGRESS) || !(flag&FLAG_NOT_DUP))
@@ -4552,6 +3923,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
tcp_init_metrics(sk);
+ tcp_init_congestion_control(tp);
+
/* Prevent spurious tcp_cwnd_restart() on first data
* packet.
*/
@@ -4708,9 +4081,6 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
if(tp->af_specific->conn_request(sk, skb) < 0)
return 1;
- init_westwood(sk);
- init_bictcp(tp);
-
/* Now we have several options: In theory there is
* nothing else in the frame. KA9Q has an option to
* send data with the syn, BSD accepts data with the
@@ -4732,9 +4102,6 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
goto discard;
case TCP_SYN_SENT:
- init_westwood(sk);
- init_bictcp(tp);
-
queued = tcp_rcv_synsent_state_process(sk, skb, th, len);
if (queued >= 0)
return queued;
@@ -4816,7 +4183,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
*/
if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
!tp->srtt)
- tcp_ack_saw_tstamp(tp, 0);
+ tcp_ack_saw_tstamp(tp, 0, 0);
if (tp->rx_opt.tstamp_ok)
tp->advmss -= TCPOLEN_TSTAMP_ALIGNED;
@@ -4828,6 +4195,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
tcp_init_metrics(sk);
+ tcp_init_congestion_control(tp);
+
/* Prevent spurious tcp_cwnd_restart() on
* first data packet.
*/
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 2d41d5d6ad1967804e7233f556c7e34c138422e8..9122814c13ad711c5cb1f87a58c8cc18e767213d 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2048,6 +2048,7 @@ static int tcp_v4_init_sock(struct sock *sk)
tp->mss_cache_std = tp->mss_cache = 536;
tp->reordering = sysctl_tcp_reordering;
+ tp->ca_ops = &tcp_reno;
sk->sk_state = TCP_CLOSE;
@@ -2070,6 +2071,8 @@ int tcp_v4_destroy_sock(struct sock *sk)
tcp_clear_xmit_timers(sk);
+ tcp_cleanup_congestion_control(tp);
+
/* Cleanup up the write buffer. */
sk_stream_writequeue_purge(sk);
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index b3943e7562f31bcadd7e81ae9994146065e15170..f42a284164b794aefec97bb296a115bc5dbc231a 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -774,6 +774,8 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
newtp->frto_counter = 0;
newtp->frto_highmark = 0;
+ newtp->ca_ops = &tcp_reno;
+
tcp_set_ca_state(newtp, TCP_CA_Open);
tcp_init_xmit_timers(newsk);
skb_queue_head_init(&newtp->out_of_order_queue);
@@ -842,8 +844,6 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
if (newtp->ecn_flags&TCP_ECN_OK)
sock_set_flag(newsk, SOCK_NO_LARGESEND);
- tcp_ca_init(newtp);
-
TCP_INC_STATS_BH(TCP_MIB_PASSIVEOPENS);
}
return newsk;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f17c6577e337f9383ebf2cecee99858167dbf7d7..0e17c244875c1cc7ca05e8fe88fddcd6a6cfb677 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -111,8 +111,7 @@ static void tcp_cwnd_restart(struct tcp_sock *tp, struct dst_entry *dst)
u32 restart_cwnd = tcp_init_cwnd(tp, dst);
u32 cwnd = tp->snd_cwnd;
- if (tcp_is_vegas(tp))
- tcp_vegas_enable(tp);
+ tcp_ca_event(tp, CA_EVENT_CWND_RESTART);
tp->snd_ssthresh = tcp_current_ssthresh(tp);
restart_cwnd = min(restart_cwnd, cwnd);
@@ -280,6 +279,10 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb)
#define SYSCTL_FLAG_WSCALE 0x2
#define SYSCTL_FLAG_SACK 0x4
+ /* If congestion control is doing timestamping */
+ if (tp->ca_ops->rtt_sample)
+ do_gettimeofday(&skb->stamp);
+
sysctl_flags = 0;
if (tcb->flags & TCPCB_FLAG_SYN) {
tcp_header_size = sizeof(struct tcphdr) + TCPOLEN_MSS;
@@ -304,17 +307,8 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb)
(tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK));
}
- /*
- * If the connection is idle and we are restarting,
- * then we don't want to do any Vegas calculations
- * until we get fresh RTT samples. So when we
- * restart, we reset our Vegas state to a clean
- * slate. After we get acks for this flight of
- * packets, _then_ we can make Vegas calculations
- * again.
- */
- if (tcp_is_vegas(tp) && tcp_packets_in_flight(tp) == 0)
- tcp_vegas_enable(tp);
+ if (tcp_packets_in_flight(tp) == 0)
+ tcp_ca_event(tp, CA_EVENT_TX_START);
th = (struct tcphdr *) skb_push(skb, tcp_header_size);
skb->h.th = th;
@@ -521,6 +515,7 @@ static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
* skbs, which it never sent before. --ANK
*/
TCP_SKB_CB(buff)->when = TCP_SKB_CB(skb)->when;
+ buff->stamp = skb->stamp;
if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST) {
tp->lost_out -= tcp_skb_pcount(skb);
@@ -1449,7 +1444,6 @@ static inline void tcp_connect_init(struct sock *sk)
tp->window_clamp = dst_metric(dst, RTAX_WINDOW);
tp->advmss = dst_metric(dst, RTAX_ADVMSS);
tcp_initialize_rcv_mss(sk);
- tcp_ca_init(tp);
tcp_select_initial_window(tcp_full_space(sk),
tp->advmss - (tp->rx_opt.ts_recent_stamp ? tp->tcp_header_len - sizeof(struct tcphdr) : 0),
@@ -1503,7 +1497,6 @@ int tcp_connect(struct sock *sk)
TCP_SKB_CB(buff)->end_seq = tp->write_seq;
tp->snd_nxt = tp->write_seq;
tp->pushed_seq = tp->write_seq;
- tcp_ca_init(tp);
/* Send it off. */
TCP_SKB_CB(buff)->when = tcp_time_stamp;
diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c
new file mode 100644
index 0000000000000000000000000000000000000000..70e108e15c71e42b5992f9ba01964d99ca70c490
--- /dev/null
+++ b/net/ipv4/tcp_scalable.c
@@ -0,0 +1,68 @@
+/* Tom Kelly's Scalable TCP
+ *
+ * See htt://www-lce.eng.cam.ac.uk/~ctk21/scalable/
+ *
+ * John Heffner <jheffner@sc.edu>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <net/tcp.h>
+
+/* These factors derived from the recommended values in the aer:
+ * .01 and and 7/8. We use 50 instead of 100 to account for
+ * delayed ack.
+ */
+#define TCP_SCALABLE_AI_CNT 50U
+#define TCP_SCALABLE_MD_SCALE 3
+
+static void tcp_scalable_cong_avoid(struct tcp_sock *tp, u32 ack, u32 rtt,
+ u32 in_flight, int flag)
+{
+ if (in_flight < tp->snd_cwnd)
+ return;
+
+ if (tp->snd_cwnd <= tp->snd_ssthresh) {
+ tp->snd_cwnd++;
+ } else {
+ tp->snd_cwnd_cnt++;
+ if (tp->snd_cwnd_cnt > min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT)){
+ tp->snd_cwnd++;
+ tp->snd_cwnd_cnt = 0;
+ }
+ }
+ tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp);
+ tp->snd_cwnd_stamp = tcp_time_stamp;
+}
+
+static u32 tcp_scalable_ssthresh(struct tcp_sock *tp)
+{
+ return max(tp->snd_cwnd - (tp->snd_cwnd>>TCP_SCALABLE_MD_SCALE), 2U);
+}
+
+
+static struct tcp_congestion_ops tcp_scalable = {
+ .ssthresh = tcp_scalable_ssthresh,
+ .cong_avoid = tcp_scalable_cong_avoid,
+ .min_cwnd = tcp_reno_min_cwnd,
+
+ .owner = THIS_MODULE,
+ .name = "scalable",
+};
+
+static int __init tcp_scalable_register(void)
+{
+ return tcp_register_congestion_control(&tcp_scalable);
+}
+
+static void __exit tcp_scalable_unregister(void)
+{
+ tcp_unregister_congestion_control(&tcp_scalable);
+}
+
+module_init(tcp_scalable_register);
+module_exit(tcp_scalable_unregister);
+
+MODULE_AUTHOR("John Heffner");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Scalable TCP");
diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c
new file mode 100644
index 0000000000000000000000000000000000000000..9bd443db5193a82c69fee4796e386106f959b705
--- /dev/null
+++ b/net/ipv4/tcp_vegas.c
@@ -0,0 +1,411 @@
+/*
+ * TCP Vegas congestion control
+ *
+ * This is based on the congestion detection/avoidance scheme described in
+ * Lawrence S. Brakmo and Larry L. Peterson.
+ * "TCP Vegas: End to end congestion avoidance on a global internet."
+ * IEEE Journal on Selected Areas in Communication, 13(8):1465--1480,
+ * October 1995. Available from:
+ * ftp://ftp.cs.arizona.edu/xkernel/Papers/jsac.ps
+ *
+ * See http://www.cs.arizona.edu/xkernel/ for their implementation.
+ * The main aspects that distinguish this implementation from the
+ * Arizona Vegas implementation are:
+ * o We do not change the loss detection or recovery mechanisms of
+ * Linux in any way. Linux already recovers from losses quite well,
+ * using fine-grained timers, NewReno, and FACK.
+ * o To avoid the performance penalty imposed by increasing cwnd
+ * only every-other RTT during slow start, we increase during
+ * every RTT during slow start, just like Reno.
+ * o Largely to allow continuous cwnd growth during slow start,
+ * we use the rate at which ACKs come back as the "actual"
+ * rate, rather than the rate at which data is sent.
+ * o To speed convergence to the right rate, we set the cwnd
+ * to achieve the right ("actual") rate when we exit slow start.
+ * o To filter out the noise caused by delayed ACKs, we use the
+ * minimum RTT sample observed during the last RTT to calculate
+ * the actual rate.
+ * o When the sender re-starts from idle, it waits until it has
+ * received ACKs for an entire flight of new data before making
+ * a cwnd adjustment decision. The original Vegas implementation
+ * assumed senders never went idle.
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/tcp_diag.h>
+
+#include <net/tcp.h>
+
+/* Default values of the Vegas variables, in fixed-point representation
+ * with V_PARAM_SHIFT bits to the right of the binary point.
+ */
+#define V_PARAM_SHIFT 1
+static int alpha = 1<<V_PARAM_SHIFT;
+static int beta = 3<<V_PARAM_SHIFT;
+static int gamma = 1<<V_PARAM_SHIFT;
+
+module_param(alpha, int, 0644);
+MODULE_PARM_DESC(alpha, "lower bound of packets in network (scale by 2)");
+module_param(beta, int, 0644);
+MODULE_PARM_DESC(beta, "upper bound of packets in network (scale by 2)");
+module_param(gamma, int, 0644);
+MODULE_PARM_DESC(gamma, "limit on increase (scale by 2)");
+
+
+/* Vegas variables */
+struct vegas {
+ u32 beg_snd_nxt; /* right edge during last RTT */
+ u32 beg_snd_una; /* left edge during last RTT */
+ u32 beg_snd_cwnd; /* saves the size of the cwnd */
+ u8 doing_vegas_now;/* if true, do vegas for this RTT */
+ u16 cntRTT; /* # of RTTs measured within last RTT */
+ u32 minRTT; /* min of RTTs measured within last RTT (in usec) */
+ u32 baseRTT; /* the min of all Vegas RTT measurements seen (in usec) */
+};
+
+/* There are several situations when we must "re-start" Vegas:
+ *
+ * o when a connection is established
+ * o after an RTO
+ * o after fast recovery
+ * o when we send a packet and there is no outstanding
+ * unacknowledged data (restarting an idle connection)
+ *
+ * In these circumstances we cannot do a Vegas calculation at the
+ * end of the first RTT, because any calculation we do is using
+ * stale info -- both the saved cwnd and congestion feedback are
+ * stale.
+ *
+ * Instead we must wait until the completion of an RTT during
+ * which we actually receive ACKs.
+ */
+static inline void vegas_enable(struct tcp_sock *tp)
+{
+ struct vegas *vegas = tcp_ca(tp);
+
+ /* Begin taking Vegas samples next time we send something. */
+ vegas->doing_vegas_now = 1;
+
+ /* Set the beginning of the next send window. */
+ vegas->beg_snd_nxt = tp->snd_nxt;
+
+ vegas->cntRTT = 0;
+ vegas->minRTT = 0x7fffffff;
+}
+
+/* Stop taking Vegas samples for now. */
+static inline void vegas_disable(struct tcp_sock *tp)
+{
+ struct vegas *vegas = tcp_ca(tp);
+
+ vegas->doing_vegas_now = 0;
+}
+
+static void tcp_vegas_init(struct tcp_sock *tp)
+{
+ struct vegas *vegas = tcp_ca(tp);
+
+ vegas->baseRTT = 0x7fffffff;
+ vegas_enable(tp);
+}
+
+/* Do RTT sampling needed for Vegas.
+ * Basically we:
+ * o min-filter RTT samples from within an RTT to get the current
+ * propagation delay + queuing delay (we are min-filtering to try to
+ * avoid the effects of delayed ACKs)
+ * o min-filter RTT samples from a much longer window (forever for now)
+ * to find the propagation delay (baseRTT)
+ */
+static void tcp_vegas_rtt_calc(struct tcp_sock *tp, u32 usrtt)
+{
+ struct vegas *vegas = tcp_ca(tp);
+ u32 vrtt = usrtt + 1; /* Never allow zero rtt or baseRTT */
+
+ /* Filter to find propagation delay: */
+ if (vrtt < vegas->baseRTT)
+ vegas->baseRTT = vrtt;
+
+ /* Find the min RTT during the last RTT to find
+ * the current prop. delay + queuing delay:
+ */
+ vegas->minRTT = min(vegas->minRTT, vrtt);
+ vegas->cntRTT++;
+}
+
+static void tcp_vegas_state(struct tcp_sock *tp, u8 ca_state)
+{
+
+ if (ca_state == TCP_CA_Open)
+ vegas_enable(tp);
+ else
+ vegas_disable(tp);
+}
+
+/*
+ * If the connection is idle and we are restarting,
+ * then we don't want to do any Vegas calculations
+ * until we get fresh RTT samples. So when we
+ * restart, we reset our Vegas state to a clean
+ * slate. After we get acks for this flight of
+ * packets, _then_ we can make Vegas calculations
+ * again.
+ */
+static void tcp_vegas_cwnd_event(struct tcp_sock *tp, enum tcp_ca_event event)
+{
+ if (event == CA_EVENT_CWND_RESTART ||
+ event == CA_EVENT_TX_START)
+ tcp_vegas_init(tp);
+}
+
+static void tcp_vegas_cong_avoid(struct tcp_sock *tp, u32 ack,
+ u32 seq_rtt, u32 in_flight, int flag)
+{
+ struct vegas *vegas = tcp_ca(tp);
+
+ if (!vegas->doing_vegas_now)
+ return tcp_reno_cong_avoid(tp, ack, seq_rtt, in_flight, flag);
+
+ /* The key players are v_beg_snd_una and v_beg_snd_nxt.
+ *
+ * These are so named because they represent the approximate values
+ * of snd_una and snd_nxt at the beginning of the current RTT. More
+ * precisely, they represent the amount of data sent during the RTT.
+ * At the end of the RTT, when we receive an ACK for v_beg_snd_nxt,
+ * we will calculate that (v_beg_snd_nxt - v_beg_snd_una) outstanding
+ * bytes of data have been ACKed during the course of the RTT, giving
+ * an "actual" rate of:
+ *
+ * (v_beg_snd_nxt - v_beg_snd_una) / (rtt duration)
+ *
+ * Unfortunately, v_beg_snd_una is not exactly equal to snd_una,
+ * because delayed ACKs can cover more than one segment, so they
+ * don't line up nicely with the boundaries of RTTs.
+ *
+ * Another unfortunate fact of life is that delayed ACKs delay the
+ * advance of the left edge of our send window, so that the number
+ * of bytes we send in an RTT is often less than our cwnd will allow.
+ * So we keep track of our cwnd separately, in v_beg_snd_cwnd.
+ */
+
+ if (after(ack, vegas->beg_snd_nxt)) {
+ /* Do the Vegas once-per-RTT cwnd adjustment. */
+ u32 old_wnd, old_snd_cwnd;
+
+
+ /* Here old_wnd is essentially the window of data that was
+ * sent during the previous RTT, and has all
+ * been acknowledged in the course of the RTT that ended
+ * with the ACK we just received. Likewise, old_snd_cwnd
+ * is the cwnd during the previous RTT.
+ */
+ old_wnd = (vegas->beg_snd_nxt - vegas->beg_snd_una) /
+ tp->mss_cache;
+ old_snd_cwnd = vegas->beg_snd_cwnd;
+
+ /* Save the extent of the current window so we can use this
+ * at the end of the next RTT.
+ */
+ vegas->beg_snd_una = vegas->beg_snd_nxt;
+ vegas->beg_snd_nxt = tp->snd_nxt;
+ vegas->beg_snd_cwnd = tp->snd_cwnd;
+
+ /* Take into account the current RTT sample too, to
+ * decrease the impact of delayed acks. This double counts
+ * this sample since we count it for the next window as well,
+ * but that's not too awful, since we're taking the min,
+ * rather than averaging.
+ */
+ tcp_vegas_rtt_calc(tp, seq_rtt*1000);
+
+ /* We do the Vegas calculations only if we got enough RTT
+ * samples that we can be reasonably sure that we got
+ * at least one RTT sample that wasn't from a delayed ACK.
+ * If we only had 2 samples total,
+ * then that means we're getting only 1 ACK per RTT, which
+ * means they're almost certainly delayed ACKs.
+ * If we have 3 samples, we should be OK.
+ */
+
+ if (vegas->cntRTT <= 2) {
+ /* We don't have enough RTT samples to do the Vegas
+ * calculation, so we'll behave like Reno.
+ */
+ if (tp->snd_cwnd > tp->snd_ssthresh)
+ tp->snd_cwnd++;
+ } else {
+ u32 rtt, target_cwnd, diff;
+
+ /* We have enough RTT samples, so, using the Vegas
+ * algorithm, we determine if we should increase or
+ * decrease cwnd, and by how much.
+ */
+
+ /* Pluck out the RTT we are using for the Vegas
+ * calculations. This is the min RTT seen during the
+ * last RTT. Taking the min filters out the effects
+ * of delayed ACKs, at the cost of noticing congestion
+ * a bit later.
+ */
+ rtt = vegas->minRTT;
+
+ /* Calculate the cwnd we should have, if we weren't
+ * going too fast.
+ *
+ * This is:
+ * (actual rate in segments) * baseRTT
+ * We keep it as a fixed point number with
+ * V_PARAM_SHIFT bits to the right of the binary point.
+ */
+ target_cwnd = ((old_wnd * vegas->baseRTT)
+ << V_PARAM_SHIFT) / rtt;
+
+ /* Calculate the difference between the window we had,
+ * and the window we would like to have. This quantity
+ * is the "Diff" from the Arizona Vegas papers.
+ *
+ * Again, this is a fixed point number with
+ * V_PARAM_SHIFT bits to the right of the binary
+ * point.
+ */
+ diff = (old_wnd << V_PARAM_SHIFT) - target_cwnd;
+
+ if (tp->snd_cwnd < tp->snd_ssthresh) {
+ /* Slow start. */
+ if (diff > gamma) {
+ /* Going too fast. Time to slow down
+ * and switch to congestion avoidance.
+ */
+ tp->snd_ssthresh = 2;
+
+ /* Set cwnd to match the actual rate
+ * exactly:
+ * cwnd = (actual rate) * baseRTT
+ * Then we add 1 because the integer
+ * truncation robs us of full link
+ * utilization.
+ */
+ tp->snd_cwnd = min(tp->snd_cwnd,
+ (target_cwnd >>
+ V_PARAM_SHIFT)+1);
+
+ }
+ } else {
+ /* Congestion avoidance. */
+ u32 next_snd_cwnd;
+
+ /* Figure out where we would like cwnd
+ * to be.
+ */
+ if (diff > beta) {
+ /* The old window was too fast, so
+ * we slow down.
+ */
+ next_snd_cwnd = old_snd_cwnd - 1;
+ } else if (diff < alpha) {
+ /* We don't have enough extra packets
+ * in the network, so speed up.
+ */
+ next_snd_cwnd = old_snd_cwnd + 1;
+ } else {
+ /* Sending just as fast as we
+ * should be.
+ */
+ next_snd_cwnd = old_snd_cwnd;
+ }
+
+ /* Adjust cwnd upward or downward, toward the
+ * desired value.
+ */
+ if (next_snd_cwnd > tp->snd_cwnd)
+ tp->snd_cwnd++;
+ else if (next_snd_cwnd < tp->snd_cwnd)
+ tp->snd_cwnd--;
+ }
+ }
+
+ /* Wipe the slate clean for the next RTT. */
+ vegas->cntRTT = 0;
+ vegas->minRTT = 0x7fffffff;
+ }
+
+ /* The following code is executed for every ack we receive,
+ * except for conditions checked in should_advance_cwnd()
+ * before the call to tcp_cong_avoid(). Mainly this means that
+ * we only execute this code if the ack actually acked some
+ * data.
+ */
+
+ /* If we are in slow start, increase our cwnd in response to this ACK.
+ * (If we are not in slow start then we are in congestion avoidance,
+ * and adjust our congestion window only once per RTT. See the code
+ * above.)
+ */
+ if (tp->snd_cwnd <= tp->snd_ssthresh)
+ tp->snd_cwnd++;
+
+ /* to keep cwnd from growing without bound */
+ tp->snd_cwnd = min_t(u32, tp->snd_cwnd, tp->snd_cwnd_clamp);
+
+ /* Make sure that we are never so timid as to reduce our cwnd below
+ * 2 MSS.
+ *
+ * Going below 2 MSS would risk huge delayed ACKs from our receiver.
+ */
+ tp->snd_cwnd = max(tp->snd_cwnd, 2U);
+}
+
+/* Extract info for Tcp socket info provided via netlink. */
+static void tcp_vegas_get_info(struct tcp_sock *tp, u32 ext,
+ struct sk_buff *skb)
+{
+ const struct vegas *ca = tcp_ca(tp);
+ if (ext & (1<<(TCPDIAG_VEGASINFO-1))) {
+ struct tcpvegas_info *info;
+
+ info = RTA_DATA(__RTA_PUT(skb, TCPDIAG_VEGASINFO,
+ sizeof(*info)));
+
+ info->tcpv_enabled = ca->doing_vegas_now;
+ info->tcpv_rttcnt = ca->cntRTT;
+ info->tcpv_rtt = ca->baseRTT;
+ info->tcpv_minrtt = ca->minRTT;
+ rtattr_failure: ;
+ }
+}
+
+static struct tcp_congestion_ops tcp_vegas = {
+ .init = tcp_vegas_init,
+ .ssthresh = tcp_reno_ssthresh,
+ .cong_avoid = tcp_vegas_cong_avoid,
+ .min_cwnd = tcp_reno_min_cwnd,
+ .rtt_sample = tcp_vegas_rtt_calc,
+ .set_state = tcp_vegas_state,
+ .cwnd_event = tcp_vegas_cwnd_event,
+ .get_info = tcp_vegas_get_info,
+
+ .owner = THIS_MODULE,
+ .name = "vegas",
+};
+
+static int __init tcp_vegas_register(void)
+{
+ BUG_ON(sizeof(struct vegas) > TCP_CA_PRIV_SIZE);
+ tcp_register_congestion_control(&tcp_vegas);
+ return 0;
+}
+
+static void __exit tcp_vegas_unregister(void)
+{
+ tcp_unregister_congestion_control(&tcp_vegas);
+}
+
+module_init(tcp_vegas_register);
+module_exit(tcp_vegas_unregister);
+
+MODULE_AUTHOR("Stephen Hemminger");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("TCP Vegas");
diff --git a/net/ipv4/tcp_westwood.c b/net/ipv4/tcp_westwood.c
new file mode 100644
index 0000000000000000000000000000000000000000..ef827242c940ec4271746111159bf8fb34441968
--- /dev/null
+++ b/net/ipv4/tcp_westwood.c
@@ -0,0 +1,259 @@
+/*
+ * TCP Westwood+
+ *
+ * Angelo Dell'Aera: TCP Westwood+ support
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/tcp_diag.h>
+#include <net/tcp.h>
+
+/* TCP Westwood structure */
+struct westwood {
+ u32 bw_ns_est; /* first bandwidth estimation..not too smoothed 8) */
+ u32 bw_est; /* bandwidth estimate */
+ u32 rtt_win_sx; /* here starts a new evaluation... */
+ u32 bk;
+ u32 snd_una; /* used for evaluating the number of acked bytes */
+ u32 cumul_ack;
+ u32 accounted;
+ u32 rtt;
+ u32 rtt_min; /* minimum observed RTT */
+};
+
+
+/* TCP Westwood functions and constants */
+#define TCP_WESTWOOD_RTT_MIN (HZ/20) /* 50ms */
+#define TCP_WESTWOOD_INIT_RTT (20*HZ) /* maybe too conservative?! */
+
+/*
+ * @tcp_westwood_create
+ * This function initializes fields used in TCP Westwood+,
+ * it is called after the initial SYN, so the sequence numbers
+ * are correct but new passive connections we have no
+ * information about RTTmin at this time so we simply set it to
+ * TCP_WESTWOOD_INIT_RTT. This value was chosen to be too conservative
+ * since in this way we're sure it will be updated in a consistent
+ * way as soon as possible. It will reasonably happen within the first
+ * RTT period of the connection lifetime.
+ */
+static void tcp_westwood_init(struct tcp_sock *tp)
+{
+ struct westwood *w = tcp_ca(tp);
+
+ w->bk = 0;
+ w->bw_ns_est = 0;
+ w->bw_est = 0;
+ w->accounted = 0;
+ w->cumul_ack = 0;
+ w->rtt_min = w->rtt = TCP_WESTWOOD_INIT_RTT;
+ w->rtt_win_sx = tcp_time_stamp;
+ w->snd_una = tp->snd_una;
+}
+
+/*
+ * @westwood_do_filter
+ * Low-pass filter. Implemented using constant coefficients.
+ */
+static inline u32 westwood_do_filter(u32 a, u32 b)
+{
+ return (((7 * a) + b) >> 3);
+}
+
+static inline void westwood_filter(struct westwood *w, u32 delta)
+{
+ w->bw_ns_est = westwood_do_filter(w->bw_ns_est, w->bk / delta);
+ w->bw_est = westwood_do_filter(w->bw_est, w->bw_ns_est);
+}
+
+/*
+ * @westwood_pkts_acked
+ * Called after processing group of packets.
+ * but all westwood needs is the last sample of srtt.
+ */
+static void tcp_westwood_pkts_acked(struct tcp_sock *tp, u32 cnt)
+{
+ struct westwood *w = tcp_ca(tp);
+ if (cnt > 0)
+ w->rtt = tp->srtt >> 3;
+}
+
+/*
+ * @westwood_update_window
+ * It updates RTT evaluation window if it is the right moment to do
+ * it. If so it calls filter for evaluating bandwidth.
+ */
+static void westwood_update_window(struct tcp_sock *tp)
+{
+ struct westwood *w = tcp_ca(tp);
+ s32 delta = tcp_time_stamp - w->rtt_win_sx;
+
+ /*
+ * See if a RTT-window has passed.
+ * Be careful since if RTT is less than
+ * 50ms we don't filter but we continue 'building the sample'.
+ * This minimum limit was chosen since an estimation on small
+ * time intervals is better to avoid...
+ * Obviously on a LAN we reasonably will always have
+ * right_bound = left_bound + WESTWOOD_RTT_MIN
+ */
+ if (w->rtt && delta > max_t(u32, w->rtt, TCP_WESTWOOD_RTT_MIN)) {
+ westwood_filter(w, delta);
+
+ w->bk = 0;
+ w->rtt_win_sx = tcp_time_stamp;
+ }
+}
+
+/*
+ * @westwood_fast_bw
+ * It is called when we are in fast path. In particular it is called when
+ * header prediction is successful. In such case in fact update is
+ * straight forward and doesn't need any particular care.
+ */
+static inline void westwood_fast_bw(struct tcp_sock *tp)
+{
+ struct westwood *w = tcp_ca(tp);
+
+ westwood_update_window(tp);
+
+ w->bk += tp->snd_una - w->snd_una;
+ w->snd_una = tp->snd_una;
+ w->rtt_min = min(w->rtt, w->rtt_min);
+}
+
+/*
+ * @westwood_acked_count
+ * This function evaluates cumul_ack for evaluating bk in case of
+ * delayed or partial acks.
+ */
+static inline u32 westwood_acked_count(struct tcp_sock *tp)
+{
+ struct westwood *w = tcp_ca(tp);
+
+ w->cumul_ack = tp->snd_una - w->snd_una;
+
+ /* If cumul_ack is 0 this is a dupack since it's not moving
+ * tp->snd_una.
+ */
+ if (!w->cumul_ack) {
+ w->accounted += tp->mss_cache;
+ w->cumul_ack = tp->mss_cache;
+ }
+
+ if (w->cumul_ack > tp->mss_cache) {
+ /* Partial or delayed ack */
+ if (w->accounted >= w->cumul_ack) {
+ w->accounted -= w->cumul_ack;
+ w->cumul_ack = tp->mss_cache;
+ } else {
+ w->cumul_ack -= w->accounted;
+ w->accounted = 0;
+ }
+ }
+
+ w->snd_una = tp->snd_una;
+
+ return w->cumul_ack;
+}
+
+static inline u32 westwood_bw_rttmin(const struct tcp_sock *tp)
+{
+ struct westwood *w = tcp_ca(tp);
+ return max_t(u32, (w->bw_est * w->rtt_min) / tp->mss_cache, 2);
+}
+
+/*
+ * TCP Westwood
+ * Here limit is evaluated as Bw estimation*RTTmin (for obtaining it
+ * in packets we use mss_cache). Rttmin is guaranteed to be >= 2
+ * so avoids ever returning 0.
+ */
+static u32 tcp_westwood_cwnd_min(struct tcp_sock *tp)
+{
+ return westwood_bw_rttmin(tp);
+}
+
+static void tcp_westwood_event(struct tcp_sock *tp, enum tcp_ca_event event)
+{
+ struct westwood *w = tcp_ca(tp);
+
+ switch(event) {
+ case CA_EVENT_FAST_ACK:
+ westwood_fast_bw(tp);
+ break;
+
+ case CA_EVENT_COMPLETE_CWR:
+ tp->snd_cwnd = tp->snd_ssthresh = westwood_bw_rttmin(tp);
+ break;
+
+ case CA_EVENT_FRTO:
+ tp->snd_ssthresh = westwood_bw_rttmin(tp);
+ break;
+
+ case CA_EVENT_SLOW_ACK:
+ westwood_update_window(tp);
+ w->bk += westwood_acked_count(tp);
+ w->rtt_min = min(w->rtt, w->rtt_min);
+ break;
+
+ default:
+ /* don't care */
+ break;
+ }
+}
+
+
+/* Extract info for Tcp socket info provided via netlink. */
+static void tcp_westwood_info(struct tcp_sock *tp, u32 ext,
+ struct sk_buff *skb)
+{
+ const struct westwood *ca = tcp_ca(tp);
+ if (ext & (1<<(TCPDIAG_VEGASINFO-1))) {
+ struct rtattr *rta;
+ struct tcpvegas_info *info;
+
+ rta = __RTA_PUT(skb, TCPDIAG_VEGASINFO, sizeof(*info));
+ info = RTA_DATA(rta);
+ info->tcpv_enabled = 1;
+ info->tcpv_rttcnt = 0;
+ info->tcpv_rtt = jiffies_to_usecs(ca->rtt);
+ info->tcpv_minrtt = jiffies_to_usecs(ca->rtt_min);
+ rtattr_failure: ;
+ }
+}
+
+
+static struct tcp_congestion_ops tcp_westwood = {
+ .init = tcp_westwood_init,
+ .ssthresh = tcp_reno_ssthresh,
+ .cong_avoid = tcp_reno_cong_avoid,
+ .min_cwnd = tcp_westwood_cwnd_min,
+ .cwnd_event = tcp_westwood_event,
+ .get_info = tcp_westwood_info,
+ .pkts_acked = tcp_westwood_pkts_acked,
+
+ .owner = THIS_MODULE,
+ .name = "westwood"
+};
+
+static int __init tcp_westwood_register(void)
+{
+ BUG_ON(sizeof(struct westwood) > TCP_CA_PRIV_SIZE);
+ return tcp_register_congestion_control(&tcp_westwood);
+}
+
+static void __exit tcp_westwood_unregister(void)
+{
+ tcp_unregister_congestion_control(&tcp_westwood);
+}
+
+module_init(tcp_westwood_register);
+module_exit(tcp_westwood_unregister);
+
+MODULE_AUTHOR("Stephen Hemminger, Angelo Dell'Aera");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("TCP Westwood+");
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 2414937f2a83f3b97985eb170e5cf73a0464976a..fce56039b0e97906c446438d2777cd1cccf86b16 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2025,7 +2025,7 @@ static int tcp_v6_init_sock(struct sock *sk)
sk->sk_state = TCP_CLOSE;
tp->af_specific = &ipv6_specific;
-
+ tp->ca_ops = &tcp_reno;
sk->sk_write_space = sk_stream_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);