Now inet_gso_segment() is stackable, its relatively easy to
implement GSO/TSO support for IPIP

Performance results, when segmentation is done after tunnel
device (as no NIC is yet enabled for TSO IPIP support) :

Before patch :

lpq83:~# ./netperf -H 7.7.9.84 -Cc
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384  16384    10.00      3357.88   5.09     3.70     2.983   2.167

After patch :

lpq83:~# ./netperf -H 7.7.9.84 -Cc
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384  16384    10.00      7710.19   4.52     6.62     1.152   1.687
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to support GSO on IPIP, we need to make
inet_gso_segment() stackable.

It should not assume network header starts right after mac
header.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch makes gre_handle_offloads() more generic
and rename it to iptunnel_handle_offloads()

This will be used to add GSO/TSO support to IPIP tunnels.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are a mix of function prototypes with and without extern
in the kernel sources.  Standardize on not using extern for
function prototypes.

Function prototypes don't need to be written with extern.
extern is assumed by the compiler.  Its use is as unnecessary as
using auto to declare automatic/local variables in a block.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

inet_gso_segment() and inet_gso_send_check() are called by
skb_mac_gso_segment() under rcu lock, no need to use
rcu_read_lock() / rcu_read_unlock()

Avoid calling ip_hdr() twice per function.

We can use ip_send_check() helper.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove the specialized code in __tcp_retransmit_skb() that tries to trim
any ACKed payload preceding a FIN before we retransmit (this was added
in 1999 in v2.2.3pre3). This trimming code was made unreachable by the
more general code added above it that uses tcp_trim_head() to trim any
ACKed payload, with or without a FIN (this was added in "[NET]: Add
segmentation offload support to TCP." in 2002 circa v2.5.33).
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The rtmsg_fib function doesn't modify this argument so mark
it const.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fib_table_lookup has included the rcu lock protection.
Signed-off-by: Nbaker.zhang <baker.kernel@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rename tcp_tso_segment() to tcp_gso_segment(), to better reflect
what is going on, and ease grep games.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Half of the rt_cache_stat fields are no longer used after IP
route cache removal, lets shrink this per cpu area.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP listener refactoring, part 6 :

Use sock_gen_put() from inet_diag_dump_one_icsk() for future
SYN_RECV support.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch registers the ARP family and he filter chain type
for this family.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Register family per netnamespace to ensure that sets are
only visible in its approapriate namespace.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch generalizes the NAT expression to support both IPv4 and IPv6
using the existing IPv4/IPv6 NAT infrastructure. This also adds the
NAT chain type for IPv6.

This patch collapses the following patches that were posted to the
netfilter-devel mailing list, from Tomasz:

* nf_tables: Change NFTA_NAT_ attributes to better semantic significance
* nf_tables: Split IPv4 NAT into NAT expression and IPv4 NAT chain
* nf_tables: Add support for IPv6 NAT expression
* nf_tables: Add support for IPv6 NAT chain
* nf_tables: Fix up build issue on IPv6 NAT support

And, from Pablo Neira Ayuso:

* fix missing dependencies in nft_chain_nat
Signed-off-by: NTomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch adds the x_tables compatibility layer. This allows you
to use existing x_tables matches and targets from nf_tables.

This compatibility later allows us to use existing matches/targets
for features that are still missing in nf_tables. We can progressively
replace them with native nf_tables extensions. It also provides the
userspace compatibility software that allows you to express the
rule-set using the iptables syntax but using the nf_tables kernel
components.

In order to get this compatibility layer working, I've done the
following things:

* add NFNL_SUBSYS_NFT_COMPAT: this new nfnetlink subsystem is used
to query the x_tables match/target revision, so we don't need to
use the native x_table getsockopt interface.

* emulate xt structures: this required extending the struct nft_pktinfo
to include the fragment offset, which is already obtained from
ip[6]_tables and that is used by some matches/targets.

* add support for default policy to base chains, required to emulate
  x_tables.

* add NFTA_CHAIN_USE attribute to obtain the number of references to
  chains, required by x_tables emulation.

* add chain packet/byte counters using per-cpu.

* support 32-64 bits compat.

For historical reasons, this patch includes the following patches
that were posted in the netfilter-devel mailing list.

From Pablo Neira Ayuso:
* nf_tables: add default policy to base chains
* netfilter: nf_tables: add NFTA_CHAIN_USE attribute
* nf_tables: nft_compat: private data of target and matches in contiguous area
* nf_tables: validate hooks for compat match/target
* nf_tables: nft_compat: release cached matches/targets
* nf_tables: x_tables support as a compile time option
* nf_tables: fix alias for xtables over nftables module
* nf_tables: add packet and byte counters per chain
* nf_tables: fix per-chain counter stats if no counters are passed
* nf_tables: don't bump chain stats
* nf_tables: add protocol and flags for xtables over nf_tables
* nf_tables: add ip[6]t_entry emulation
* nf_tables: move specific layer 3 compat code to nf_tables_ipv[4|6]
* nf_tables: support 32bits-64bits x_tables compat
* nf_tables: fix compilation if CONFIG_COMPAT is disabled

From Patrick McHardy:
* nf_tables: move policy to struct nft_base_chain
* nf_tables: send notifications for base chain policy changes

From Alexander Primak:
* nf_tables: remove the duplicate NF_INET_LOCAL_OUT

From Nicolas Dichtel:
* nf_tables: fix compilation when nf-netlink is a module
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch converts built-in tables/chains to chain types that
allows you to deploy customized table and chain configurations from
userspace.

After this patch, you have to specify the chain type when
creating a new chain:

 add chain ip filter output { type filter hook input priority 0; }
                              ^^^^ ------

The existing chain types after this patch are: filter, route and
nat. Note that tables are just containers of chains with no specific
semantics, which is a significant change with regards to iptables.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Split the expression ops into two parts and support overloading of
the runtime expression ops based on the requested function through
a ->select_ops() callback.

This can be used to provide optimized implementations, for instance
for loading small aligned amounts of data from the packet or inlining
frequently used operations into the main evaluation loop.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch adds nftables which is the intended successor of iptables.
This packet filtering framework reuses the existing netfilter hooks,
the connection tracking system, the NAT subsystem, the transparent
proxying engine, the logging infrastructure and the userspace packet
queueing facilities.

In a nutshell, nftables provides a pseudo-state machine with 4 general
purpose registers of 128 bits and 1 specific purpose register to store
verdicts. This pseudo-machine comes with an extensible instruction set,
a.k.a. "expressions" in the nftables jargon. The expressions included
in this patch provide the basic functionality, they are:

* bitwise: to perform bitwise operations.
* byteorder: to change from host/network endianess.
* cmp: to compare data with the content of the registers.
* counter: to enable counters on rules.
* ct: to store conntrack keys into register.
* exthdr: to match IPv6 extension headers.
* immediate: to load data into registers.
* limit: to limit matching based on packet rate.
* log: to log packets.
* meta: to match metainformation that usually comes with the skbuff.
* nat: to perform Network Address Translation.
* payload: to fetch data from the packet payload and store it into
  registers.
* reject (IPv4 only): to explicitly close connection, eg. TCP RST.

Using this instruction-set, the userspace utility 'nft' can transform
the rules expressed in human-readable text representation (using a
new syntax, inspired by tcpdump) to nftables bytecode.

nftables also inherits the table, chain and rule objects from
iptables, but in a more configurable way, and it also includes the
original datatype-agnostic set infrastructure with mapping support.
This set infrastructure is enhanced in the follow up patch (netfilter:
nf_tables: add netlink set API).

This patch includes the following components:

* the netlink API: net/netfilter/nf_tables_api.c and
  include/uapi/netfilter/nf_tables.h
* the packet filter core: net/netfilter/nf_tables_core.c
* the expressions (described above): net/netfilter/nft_*.c
* the filter tables: arp, IPv4, IPv6 and bridge:
  net/ipv4/netfilter/nf_tables_ipv4.c
  net/ipv6/netfilter/nf_tables_ipv6.c
  net/ipv4/netfilter/nf_tables_arp.c
  net/bridge/netfilter/nf_tables_bridge.c
* the NAT table (IPv4 only):
  net/ipv4/netfilter/nf_table_nat_ipv4.c
* the route table (similar to mangle):
  net/ipv4/netfilter/nf_table_route_ipv4.c
  net/ipv6/netfilter/nf_table_route_ipv6.c
* internal definitions under:
  include/net/netfilter/nf_tables.h
  include/net/netfilter/nf_tables_core.h
* It also includes an skeleton expression:
  net/netfilter/nft_expr_template.c
  and the preliminary implementation of the meta target
  net/netfilter/nft_meta_target.c

It also includes a change in struct nf_hook_ops to add a new
pointer to store private data to the hook, that is used to store
the rule list per chain.

This patch is based on the patch from Patrick McHardy, plus merged
accumulated cleanups, fixes and small enhancements to the nftables
code that has been done since 2009, which are:

From Patrick McHardy:
* nf_tables: adjust netlink handler function signatures
* nf_tables: only retry table lookup after successful table module load
* nf_tables: fix event notification echo and avoid unnecessary messages
* nft_ct: add l3proto support
* nf_tables: pass expression context to nft_validate_data_load()
* nf_tables: remove redundant definition
* nft_ct: fix maxattr initialization
* nf_tables: fix invalid event type in nf_tables_getrule()
* nf_tables: simplify nft_data_init() usage
* nf_tables: build in more core modules
* nf_tables: fix double lookup expression unregistation
* nf_tables: move expression initialization to nf_tables_core.c
* nf_tables: build in payload module
* nf_tables: use NFPROTO constants
* nf_tables: rename pid variables to portid
* nf_tables: save 48 bits per rule
* nf_tables: introduce chain rename
* nf_tables: check for duplicate names on chain rename
* nf_tables: remove ability to specify handles for new rules
* nf_tables: return error for rule change request
* nf_tables: return error for NLM_F_REPLACE without rule handle
* nf_tables: include NLM_F_APPEND/NLM_F_REPLACE flags in rule notification
* nf_tables: fix NLM_F_MULTI usage in netlink notifications
* nf_tables: include NLM_F_APPEND in rule dumps

From Pablo Neira Ayuso:
* nf_tables: fix stack overflow in nf_tables_newrule
* nf_tables: nft_ct: fix compilation warning
* nf_tables: nft_ct: fix crash with invalid packets
* nft_log: group and qthreshold are 2^16
* nf_tables: nft_meta: fix socket uid,gid handling
* nft_counter: allow to restore counters
* nf_tables: fix module autoload
* nf_tables: allow to remove all rules placed in one chain
* nf_tables: use 64-bits rule handle instead of 16-bits
* nf_tables: fix chain after rule deletion
* nf_tables: improve deletion performance
* nf_tables: add missing code in route chain type
* nf_tables: rise maximum number of expressions from 12 to 128
* nf_tables: don't delete table if in use
* nf_tables: fix basechain release

From Tomasz Bursztyka:
* nf_tables: Add support for changing users chain's name
* nf_tables: Change chain's name to be fixed sized
* nf_tables: Add support for replacing a rule by another one
* nf_tables: Update uapi nftables netlink header documentation

From Florian Westphal:
* nft_log: group is u16, snaplen u32

From Phil Oester:
* nf_tables: operational limit match
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Pass the hook ops to the hookfn to allow for generic hook
functions. This change is required by nf_tables.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

1) We need to take a timestamp only for skb that should be cloned.

Other skbs are not in write queue and no rtt estimation is done on them.

2) the unlikely() hint is wrong for receivers (they send pure ACK)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: MF Nowlan <fitz@cs.yale.edu>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-By: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit 634fb979 ("inet: includes a sock_common in request_sock")
I forgot that the two ports in sock_common do not have same byte order :

skc_dport is __be16 (network order), but skc_num is __u16 (host order)

So sparse complains because ir_loc_port (mapped into skc_num) is
considered as __u16 while it should be __be16

Let rename ir_loc_port to ireq->ir_num (analogy with inet->inet_num),
and perform appropriate htons/ntohs conversions.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sk_pacing_rate is read by sch_fq packet scheduler at any time,
with no synchronization, so make sure we update it in a
sensible way. ACCESS_ONCE() is how we instruct compiler
to not do stupid things, like using the memory location
as a temporary variable.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP listener refactoring, part 5 :

We want to be able to insert request sockets (SYN_RECV) into main
ehash table instead of the per listener hash table to allow RCU
lookups and remove listener lock contention.

This patch includes the needed struct sock_common in front
of struct request_sock

This means there is no more inet6_request_sock IPv6 specific
structure.

Following inet_request_sock fields were renamed as they became
macros to reference fields from struct sock_common.
Prefix ir_ was chosen to avoid name collisions.

loc_port   -> ir_loc_port
loc_addr   -> ir_loc_addr
rmt_addr   -> ir_rmt_addr
rmt_port   -> ir_rmt_port
iif        -> ir_iif
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a enhancement.

for the first node in fib_trie, newpos is 0, bit is 1.
Only for the leaf or node with unmatched key need calc pos.
Signed-off-by: Nbaker.zhang <baker.kernel@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

CONFIG_IPV6=n is still a valid choice ;)

It appears we can remove dead code.
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

At this point sk might contain garbage.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP listener refactoring, part 4 :

To speed up inet lookups, we moved IPv4 addresses from inet to struct
sock_common

Now is time to do the same for IPv6, because it permits us to have fast
lookups for all kind of sockets, including upcoming SYN_RECV.

Getting IPv6 addresses in TCP lookups currently requires two extra cache
lines, plus a dereference (and memory stall).

inet6_sk(sk) does the dereference of inet_sk(__sk)->pinet6

This patch is way bigger than its IPv4 counter part, because for IPv4,
we could add aliases (inet_daddr, inet_rcv_saddr), while on IPv6,
it's not doable easily.

inet6_sk(sk)->daddr becomes sk->sk_v6_daddr
inet6_sk(sk)->rcv_saddr becomes sk->sk_v6_rcv_saddr

And timewait socket also have tw->tw_v6_daddr & tw->tw_v6_rcv_saddr
at the same offset.

We get rid of INET6_TW_MATCH() as INET6_MATCH() is now the generic
macro.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP listener refactoring, part 3 :

Our goal is to hash SYN_RECV sockets into main ehash for fast lookup,
and parallel SYN processing.

Current inet_ehash_bucket contains two chains, one for ESTABLISH (and
friend states) sockets, another for TIME_WAIT sockets only.

As the hash table is sized to get at most one socket per bucket, it
makes little sense to have separate twchain, as it makes the lookup
slightly more complicated, and doubles hash table memory usage.

If we make sure all socket types have the lookup keys at the same
offsets, we can use a generic and faster lookup. It turns out TIME_WAIT
and ESTABLISHED sockets already have common lookup fields for IPv4.

[ INET_TW_MATCH() is no longer needed ]

I'll provide a follow-up to factorize IPv6 lookup as well, to remove
INET6_TW_MATCH()

This way, SYN_RECV pseudo sockets will be supported the same.

A new sock_gen_put() helper is added, doing either a sock_put() or
inet_twsk_put() [ and will support SYN_RECV later ].

Note this helper should only be called in real slow path, when rcu
lookup found a socket that was moved to another identity (freed/reused
immediately), but could eventually be used in other contexts, like
sock_edemux()

Before patch :

dmesg | grep "TCP established"

TCP established hash table entries: 524288 (order: 11, 8388608 bytes)

After patch :

TCP established hash table entries: 524288 (order: 10, 4194304 bytes)
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The since the removal of the routing cache computing
fib_compute_spec_dst() does a fib_table lookup for each UDP multicast
packet received.  This has introduced a performance regression for some
UDP workloads.

This change skips populating the packet info for sockets that do not have
IP_PKTINFO set.

Benchmark results from a netperf UDP_RR test:
Before 89789.68 transactions/s
After  90587.62 transactions/s

Benchmark results from a fio 1 byte UDP multicast pingpong test
(Multicast one way unicast response):
Before 12.63us RTT
After  12.48us RTT
Signed-off-by: NShawn Bohrer <sbohrer@rgmadvisors.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The removal of the routing cache introduced a performance regression for
some UDP workloads since a dst lookup must be done for each packet.
This change caches the dst per socket in a similar manner to what we do
for TCP by implementing early_demux.

For UDP multicast we can only cache the dst if there is only one
receiving socket on the host.  Since caching only works when there is
one receiving socket we do the multicast socket lookup using RCU.

For UDP unicast we only demux sockets with an exact match in order to
not break forwarding setups.  Additionally since the hash chains may be
long we only check the first socket to see if it is a match and not
waste extra time searching the whole chain when we might not find an
exact match.

Benchmark results from a netperf UDP_RR test:
Before 87961.22 transactions/s
After  89789.68 transactions/s

Benchmark results from a fio 1 byte UDP multicast pingpong test
(Multicast one way unicast response):
Before 12.97us RTT
After  12.63us RTT
Signed-off-by: NShawn Bohrer <sbohrer@rgmadvisors.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP sockets can receive packets from multiple endpoints and thus may be
received on multiple receive queues.  Since packets packets can arrive
on multiple receive queues we should not mark the napi_id for all
packets.  This makes busy read/poll only work for connected UDP sockets.

This additionally enables busy read/poll for UDP multicast packets as
long as the socket is connected by moving the check into
__udp_queue_rcv_skb().
Signed-off-by: NShawn Bohrer <sbohrer@rgmadvisors.com>
Suggested-by: NEric Dumazet <edumazet@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When sending out multicast messages, the source address in inet->mc_addr is
ignored and rewritten by an autoselected one. This is caused by a typo in
commit 813b3b5d ("ipv4: Use caller's on-stack flowi as-is in output
route lookups").
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Yuchung found following problem :

 There are bugs in the SACK processing code, merging part in
 tcp_shift_skb_data(), that incorrectly resets or ignores the sacked
 skbs FIN flag. When a receiver first SACK the FIN sequence, and later
 throw away ofo queue (e.g., sack-reneging), the sender will stop
 retransmitting the FIN flag, and hangs forever.

Following packetdrill test can be used to reproduce the bug.

$ cat sack-merge-bug.pkt
`sysctl -q net.ipv4.tcp_fack=0`

// Establish a connection and send 10 MSS.
0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+.000 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
+.000 bind(3, ..., ...) = 0
+.000 listen(3, 1) = 0

+.050 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
+.000 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 6>
+.001 < . 1:1(0) ack 1 win 1024
+.000 accept(3, ..., ...) = 4

+.100 write(4, ..., 12000) = 12000
+.000 shutdown(4, SHUT_WR) = 0
+.000 > . 1:10001(10000) ack 1
+.050 < . 1:1(0) ack 2001 win 257
+.000 > FP. 10001:12001(2000) ack 1
+.050 < . 1:1(0) ack 2001 win 257 <sack 10001:11001,nop,nop>
+.050 < . 1:1(0) ack 2001 win 257 <sack 10001:12002,nop,nop>
// SACK reneg
+.050 < . 1:1(0) ack 12001 win 257
+0 %{ print "unacked: ",tcpi_unacked }%
+5 %{ print "" }%

First, a typo inverted left/right of one OR operation, then
code forgot to advance end_seq if the merged skb carried FIN.

Bug was added in 2.6.29 by commit 832d11c5
("tcp: Try to restore large SKBs while SACK processing")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Acked-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While working on tcp listener refactoring, I found that it
would really make things easier if sock_common could include
the IPv6 addresses needed in the lookups, instead of doing
very complex games to get their values (depending on sock
being SYN_RECV, ESTABLISHED, TIME_WAIT)

For this to happen, I need to be sure that tcp6_timewait_sock
and tcp_timewait_sock consume same number of cache lines.

This is possible if we only use 32bits for tw_ttd, as we remove
one 32bit hole in inet_timewait_sock

inet_tw_time_stamp() is defined and used, even if its current
implementation looks like tcp_time_stamp : We might need finer
resolution for tcp_time_stamp in the future.

Before patch : sizeof(struct tcp6_timewait_sock) = 0xc8

After patch : sizeof(struct tcp6_timewait_sock) = 0xc0
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The variable fully_acked is only assigned the values true and false.
Change its type to bool.

The simplified semantic patch that find this problem is as
follows (http://coccinelle.lip6.fr/):

@exists@
type T;
identifier b;
@@
- T
+ bool
  b = ...;
  ... when any
  b = \(true\|false\)
Signed-off-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP listener refactoring, part 2 :

We can use a generic lookup, sockets being in whatever state, if
we are sure all relevant fields are at the same place in all socket
types (ESTABLISH, TIME_WAIT, SYN_RECV)

This patch removes these macros :

 inet_addrpair, inet_addrpair, tw_addrpair, tw_portpair

And adds :

 sk_portpair, sk_addrpair, sk_daddr, sk_rcv_saddr

Then, INET_TW_MATCH() is really the same than INET_MATCH()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 3ab5aee7 ("net: Convert TCP & DCCP hash tables to use RCU /
hlist_nulls") incorrectly used sock_put() on TIMEWAIT sockets.

We should instead use inet_twsk_put()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_fixup_sndbuf() is underestimating initial send buffer requirements.

It was not noticed because big GSO packets were escaping the limitation,
but with smaller TSO packets (or TSO/GSO/SG off), application hits
sk_sndbuf before having a chance to fill enough packets in socket write
queue.

- initial cwnd can be bigger than 10 for specific routes

- SKB_TRUESIZE() is a bit under real needs in some cases,
  because of power-of-two rounding in kmalloc()

- Fast Recovery (RFC 5681 3.2) : Cubic needs 70% factor

- Extra cushion (application might react slowly to POLLOUT)

tcp_v4_conn_req_fastopen() needs to call tcp_init_metrics() before
calling tcp_init_buffer_space()

Then we realize tcp_new_space() should call tcp_fixup_sndbuf()
instead of duplicating this stuff.

Rename tcp_fixup_sndbuf() to tcp_sndbuf_expand() to be more
descriptive.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Acked-by: NMaciej Żenczykowski <maze@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Because 'node' is the i'st child of 'oldnode',
thus, here 'i' equals
tkey_extract_bits(node->key, oldtnode->pos, oldtnode->bits)

we just get 1 more bit,
and need not care the detail value of this bits.

I apologize for the mistake.

I generated the patch on a branch version,
and did not notice the put_child has been changed.

I have redone the test on HEAD version with my patch.

two cases are used.
case 1. inflate a node which has a leaf child node.
case 2: inflate a node which has a an child node with skipped bits

test env:
  ip link set eth0 up
  ip a add dev eth0 192.168.11.1/32
here, we just focus on route table(MAIN),
so I use a "192.168.11.1/32" address to simplify the test case.

call trace:
+ fib_insert_node
+ + trie_rebalance
+ + + resize
+ + + + inflate

Test case 1:  inflate a node which has a leaf child node.

===========================================================
step 1. prepare a fib trie
------------------------------------------
  ip r a 192.168.0.0/24 via 192.168.11.1
  ip r a 192.168.1.0/24 via 192.168.11.1

we get a fib trie.
root@baker:~# cat /proc/net/fib_trie
Main:
  +-- 192.168.0.0/23 1 0 0
   |-- 192.168.0.0
    /24 universe UNICAST
   |-- 192.168.1.0
    /24 universe UNICAST
Local:
.....

step 2. Add the third route
------------------------------------------
root@baker:~# ip r a 192.168.2.0/24 via 192.168.11.1

A fib_trie leaf will be inserted in fib_insert_node before trie_rebalance.

For function 'inflate':
'inflate' is called with following trie.
  +-- 192.168.0.0/22 1 1 0 <=== tn node
    +-- 192.168.0.0/23 1 0 0    <== node a
        |-- 192.168.0.0
          /24 universe UNICAST
        |-- 192.168.1.0
          /24 universe UNICAST
      |-- 192.168.2.0          <== leaf(node b)

When process node b, which is a leaf. here:
i is 1,
node key "192.168.2.0"
oldnode is (pos:22, bits:1)

unpatch source:
tkey_extract_bits(node->key, oldtnode->pos + oldtnode->bits, 1)
it equals:
tkey_extract_bits("192.168,2,0", 22 + 1, 1)

thus got 0, and call put_child(tn, 2*i, node); <== 2*i=2.

patched source:
tkey_extract_bits(node->key, oldtnode->pos, oldtnode->bits + 1),
tkey_extract_bits("192.168,2,0", 22, 1 + 1)  <== get 2.

Test case 2:  inflate a node which has a an child node with skipped bits
==========================================================================
step 1. prepare a fib trie.
  ip link set eth0 up
  ip a add dev eth0 192.168.11.1/32
  ip r a 192.168.128.0/24 via 192.168.11.1
  ip r a 192.168.0.0/24  via 192.168.11.1
  ip r a 192.168.16.0/24   via 192.168.11.1
  ip r a 192.168.32.0/24  via 192.168.11.1
  ip r a 192.168.48.0/24  via 192.168.11.1
  ip r a 192.168.144.0/24   via 192.168.11.1
  ip r a 192.168.160.0/24   via 192.168.11.1
  ip r a 192.168.176.0/24   via 192.168.11.1

check:
root@baker:~# cat /proc/net/fib_trie
Main:
  +-- 192.168.0.0/16 1 0 0
     +-- 192.168.0.0/18 2 0 0
        |-- 192.168.0.0
           /24 universe UNICAST
        |-- 192.168.16.0
           /24 universe UNICAST
        |-- 192.168.32.0
           /24 universe UNICAST
        |-- 192.168.48.0
           /24 universe UNICAST
     +-- 192.168.128.0/18 2 0 0
        |-- 192.168.128.0
           /24 universe UNICAST
        |-- 192.168.144.0
           /24 universe UNICAST
        |-- 192.168.160.0
           /24 universe UNICAST
        |-- 192.168.176.0
           /24 universe UNICAST
Local:
  ...

step 2. add a route to trigger inflate.
  ip r a 192.168.96.0/24   via 192.168.11.1

This command will call serveral times inflate.
In the first time, the fib_trie is:
________________________
+-- 192.168.128.0/(16, 1) <== tn node
 +-- 192.168.0.0/(17, 1)  <== node a
  +-- 192.168.0.0/(18, 2)
   |-- 192.168.0.0
   |-- 192.168.16.0
   |-- 192.168.32.0
   |-- 192.168.48.0
  |-- 192.168.96.0
 +-- 192.168.128.0/(18, 2) <== node b.
  |-- 192.168.128.0
  |-- 192.168.144.0
  |-- 192.168.160.0
  |-- 192.168.176.0

NOTE: node b is a interal node with skipped bits.
here,
i:1,
node->key "192.168.128.0",
oldnode:(pos:16, bits:1)
so
tkey_extract_bits(node->key, oldtnode->pos + oldtnode->bits, 1)
it equals:
tkey_extract_bits("192.168,128,0", 16 + 1, 1) <=== 0

tkey_extract_bits(node->key, oldtnode->pos, oldtnode->bits, 1)
it equals:
tkey_extract_bits("192.168,128,0", 16, 1+1) <=== 2

2*i + 0 == 2, so the result is same.
Signed-off-by: Nbaker.zhang <baker.kernel@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_established_options assumes opts->options is 0 before calling,
as it read modify writes it.

For the tcp_current_mss() case the opts structure is not zeroed,
so this can be done with uninitialized values.

This is ok, because ->options is not read in this path.
But it's still better to avoid the operation on the uninitialized
field. This shuts up a static code analyzer, and presumably
may help the optimizer.

Cc: netdev@vger.kernel.org
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>