提交 5f8ef48d 编写于 作者: S Stephen Hemminger 提交者: David S. Miller

[TCP]: Allow choosing TCP congestion control via sockopt.

Allow using setsockopt to set TCP congestion control to use on a per
socket basis.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 51b0bded
......@@ -127,6 +127,7 @@ enum {
#define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
#define TCP_INFO 11 /* Information about this connection. */
#define TCP_QUICKACK 12 /* Block/reenable quick acks */
#define TCP_CONGESTION 13 /* Congestion control algorithm */
#define TCPI_OPT_TIMESTAMPS 1
#define TCPI_OPT_SACK 2
......
......@@ -1162,8 +1162,9 @@ 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 int tcp_set_congestion_control(struct tcp_sock *tp, const char *name);
extern struct tcp_congestion_ops tcp_reno;
extern struct tcp_congestion_ops tcp_init_congestion_ops;
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);
......
......@@ -1927,6 +1927,25 @@ int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
return tp->af_specific->setsockopt(sk, level, optname,
optval, optlen);
/* This is a string value all the others are int's */
if (optname == TCP_CONGESTION) {
char name[TCP_CA_NAME_MAX];
if (optlen < 1)
return -EINVAL;
val = strncpy_from_user(name, optval,
min(TCP_CA_NAME_MAX-1, optlen));
if (val < 0)
return -EFAULT;
name[val] = 0;
lock_sock(sk);
err = tcp_set_congestion_control(tp, name);
release_sock(sk);
return err;
}
if (optlen < sizeof(int))
return -EINVAL;
......@@ -2211,6 +2230,16 @@ int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
case TCP_QUICKACK:
val = !tp->ack.pingpong;
break;
case TCP_CONGESTION:
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, tp->ca_ops->name, len))
return -EFAULT;
return 0;
default:
return -ENOPROTOOPT;
};
......@@ -2224,7 +2253,7 @@ int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
extern void __skb_cb_too_small_for_tcp(int, int);
extern void tcpdiag_init(void);
extern struct tcp_congestion_ops tcp_reno;
static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
......
......@@ -21,7 +21,7 @@ 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) {
list_for_each_entry_rcu(e, &tcp_cong_list, list) {
if (strcmp(e->name, name) == 0)
return e;
}
......@@ -77,6 +77,9 @@ void tcp_init_congestion_control(struct tcp_sock *tp)
{
struct tcp_congestion_ops *ca;
if (tp->ca_ops != &tcp_init_congestion_ops)
return;
rcu_read_lock();
list_for_each_entry_rcu(ca, &tcp_cong_list, list) {
if (try_module_get(ca->owner)) {
......@@ -139,6 +142,34 @@ void tcp_get_default_congestion_control(char *name)
rcu_read_unlock();
}
/* Change congestion control for socket */
int tcp_set_congestion_control(struct tcp_sock *tp, const char *name)
{
struct tcp_congestion_ops *ca;
int err = 0;
rcu_read_lock();
ca = tcp_ca_find(name);
if (ca == tp->ca_ops)
goto out;
if (!ca)
err = -ENOENT;
else if (!try_module_get(ca->owner))
err = -EBUSY;
else {
tcp_cleanup_congestion_control(tp);
tp->ca_ops = ca;
if (tp->ca_ops->init)
tp->ca_ops->init(tp);
}
out:
rcu_read_unlock();
return err;
}
/*
* TCP Reno congestion control
* This is special case used for fallback as well.
......@@ -192,4 +223,15 @@ struct tcp_congestion_ops tcp_reno = {
.min_cwnd = tcp_reno_min_cwnd,
};
EXPORT_SYMBOL_GPL(tcp_reno);
/* Initial congestion control used (until SYN)
* really reno under another name so we can tell difference
* during tcp_set_default_congestion_control
*/
struct tcp_congestion_ops tcp_init_congestion_ops = {
.name = "",
.owner = THIS_MODULE,
.ssthresh = tcp_reno_ssthresh,
.cong_avoid = tcp_reno_cong_avoid,
.min_cwnd = tcp_reno_min_cwnd,
};
EXPORT_SYMBOL_GPL(tcp_init_congestion_ops);
......@@ -2048,7 +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;
tp->ca_ops = &tcp_init_congestion_ops;
sk->sk_state = TCP_CLOSE;
......
......@@ -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;
tp->ca_ops = &tcp_init_congestion_ops;
sk->sk_write_space = sk_stream_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
......
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