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tcp: move duplicate code from tcp_v4_init_sock()/tcp_v6_init_sock()

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This commit moves the (substantial) common code shared between
tcp_v4_init_sock() and tcp_v6_init_sock() to a new address-family
independent function, tcp_init_sock().

Centralizing this functionality should help avoid drift issues,
e.g. where the IPv4 side is updated without a corresponding update to
IPv6. There was already some drift: IPv4 initialized snd_cwnd to
TCP_INIT_CWND, while the IPv6 side was still initializing snd_cwnd to
2 (in this case it should not matter, since snd_cwnd is also
initialized in tcp_init_metrics(), but the general risks and
maintenance overhead remain).

When diffing the old and new code, note that new tcp_init_sock()
function uses the order of steps from the tcp_v4_init_sock()
implementation (the order is slightly different in
tcp_v6_init_sock()).

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Neal Cardwell 2012-04-19 09:55:21 +00:00 committed by David S. Miller
parent e66e9a3147
commit 900f65d361
4 changed files with 68 additions and 99 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
include/net/tcp.h
View file

@ -395,6 +395,7 @@ extern void tcp_enter_loss(struct sock *sk, int how);
extern void tcp_clear_retrans(struct tcp_sock *tp); extern void tcp_clear_retrans(struct tcp_sock *tp);
extern void tcp_update_metrics(struct sock *sk); extern void tcp_update_metrics(struct sock *sk);
extern void tcp_close(struct sock *sk, long timeout); extern void tcp_close(struct sock *sk, long timeout);
extern void tcp_init_sock(struct sock *sk);
extern unsigned int tcp_poll(struct file * file, struct socket *sock, extern unsigned int tcp_poll(struct file * file, struct socket *sock,
struct poll_table_struct *wait); struct poll_table_struct *wait);
extern int tcp_getsockopt(struct sock *sk, int level, int optname, extern int tcp_getsockopt(struct sock *sk, int level, int optname,

64
net/ipv4/tcp.c
View file

@ -363,6 +363,70 @@ static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
return period; return period;
} }
/* Address-family independent initialization for a tcp_sock.
*
* NOTE: A lot of things set to zero explicitly by call to
* sk_alloc() so need not be done here.
*/
void tcp_init_sock(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
skb_queue_head_init(&tp->out_of_order_queue);
tcp_init_xmit_timers(sk);
tcp_prequeue_init(tp);
icsk->icsk_rto = TCP_TIMEOUT_INIT;
tp->mdev = TCP_TIMEOUT_INIT;
/* So many TCP implementations out there (incorrectly) count the
* initial SYN frame in their delayed-ACK and congestion control
* algorithms that we must have the following bandaid to talk
* efficiently to them. -DaveM
*/
tp->snd_cwnd = TCP_INIT_CWND;
/* See draft-stevens-tcpca-spec-01 for discussion of the
* initialization of these values.
*/
tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
tp->snd_cwnd_clamp = ~0;
tp->mss_cache = TCP_MSS_DEFAULT;
tp->reordering = sysctl_tcp_reordering;
icsk->icsk_ca_ops = &tcp_init_congestion_ops;
sk->sk_state = TCP_CLOSE;
sk->sk_write_space = sk_stream_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
icsk->icsk_sync_mss = tcp_sync_mss;
/* TCP Cookie Transactions */
if (sysctl_tcp_cookie_size > 0) {
/* Default, cookies without s_data_payload. */
tp->cookie_values =
kzalloc(sizeof(*tp->cookie_values),
sk->sk_allocation);
if (tp->cookie_values != NULL)
kref_init(&tp->cookie_values->kref);
}
/* Presumed zeroed, in order of appearance:
* cookie_in_always, cookie_out_never,
* s_data_constant, s_data_in, s_data_out
*/
sk->sk_sndbuf = sysctl_tcp_wmem[1];
sk->sk_rcvbuf = sysctl_tcp_rmem[1];
local_bh_disable();
sock_update_memcg(sk);
sk_sockets_allocated_inc(sk);
local_bh_enable();
}
EXPORT_SYMBOL(tcp_init_sock);
/* /*
* Wait for a TCP event. * Wait for a TCP event.
* *

52
net/ipv4/tcp_ipv4.c
View file

@ -1890,62 +1890,14 @@ static int tcp_v4_init_sock(struct sock *sk)
struct inet_connection_sock *icsk = inet_csk(sk); struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk); struct tcp_sock *tp = tcp_sk(sk);
skb_queue_head_init(&tp->out_of_order_queue); tcp_init_sock(sk);
tcp_init_xmit_timers(sk);
tcp_prequeue_init(tp);
icsk->icsk_rto = TCP_TIMEOUT_INIT;
tp->mdev = TCP_TIMEOUT_INIT;
/* So many TCP implementations out there (incorrectly) count the
* initial SYN frame in their delayed-ACK and congestion control
* algorithms that we must have the following bandaid to talk
* efficiently to them. -DaveM
*/
tp->snd_cwnd = TCP_INIT_CWND;
/* See draft-stevens-tcpca-spec-01 for discussion of the
* initialization of these values.
*/
tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
tp->snd_cwnd_clamp = ~0;
tp->mss_cache = TCP_MSS_DEFAULT;
tp->reordering = sysctl_tcp_reordering;
icsk->icsk_ca_ops = &tcp_init_congestion_ops;
sk->sk_state = TCP_CLOSE;
sk->sk_write_space = sk_stream_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
icsk->icsk_af_ops = &ipv4_specific; icsk->icsk_af_ops = &ipv4_specific;
icsk->icsk_sync_mss = tcp_sync_mss;
#ifdef CONFIG_TCP_MD5SIG #ifdef CONFIG_TCP_MD5SIG
tp->af_specific = &tcp_sock_ipv4_specific; tp->af_specific = &tcp_sock_ipv4_specific;
#endif #endif
/* TCP Cookie Transactions */
if (sysctl_tcp_cookie_size > 0) {
/* Default, cookies without s_data_payload. */
tp->cookie_values =
kzalloc(sizeof(*tp->cookie_values),
sk->sk_allocation);
if (tp->cookie_values != NULL)
kref_init(&tp->cookie_values->kref);
}
/* Presumed zeroed, in order of appearance:
* cookie_in_always, cookie_out_never,
* s_data_constant, s_data_in, s_data_out
*/
sk->sk_sndbuf = sysctl_tcp_wmem[1];
sk->sk_rcvbuf = sysctl_tcp_rmem[1];
local_bh_disable();
sock_update_memcg(sk);
sk_sockets_allocated_inc(sk);
local_bh_enable();
return 0; return 0;
} }

50
net/ipv6/tcp_ipv6.c
View file

@ -1831,62 +1831,14 @@ static int tcp_v6_init_sock(struct sock *sk)
struct inet_connection_sock *icsk = inet_csk(sk); struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk); struct tcp_sock *tp = tcp_sk(sk);
skb_queue_head_init(&tp->out_of_order_queue); tcp_init_sock(sk);
tcp_init_xmit_timers(sk);
tcp_prequeue_init(tp);
icsk->icsk_rto = TCP_TIMEOUT_INIT;
tp->mdev = TCP_TIMEOUT_INIT;
/* So many TCP implementations out there (incorrectly) count the
* initial SYN frame in their delayed-ACK and congestion control
* algorithms that we must have the following bandaid to talk
* efficiently to them. -DaveM
*/
tp->snd_cwnd = 2;
/* See draft-stevens-tcpca-spec-01 for discussion of the
* initialization of these values.
*/
tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
tp->snd_cwnd_clamp = ~0;
tp->mss_cache = TCP_MSS_DEFAULT;
tp->reordering = sysctl_tcp_reordering;
sk->sk_state = TCP_CLOSE;
icsk->icsk_af_ops = &ipv6_specific; icsk->icsk_af_ops = &ipv6_specific;
icsk->icsk_ca_ops = &tcp_init_congestion_ops;
icsk->icsk_sync_mss = tcp_sync_mss;
sk->sk_write_space = sk_stream_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
#ifdef CONFIG_TCP_MD5SIG #ifdef CONFIG_TCP_MD5SIG
tp->af_specific = &tcp_sock_ipv6_specific; tp->af_specific = &tcp_sock_ipv6_specific;
#endif #endif
/* TCP Cookie Transactions */
if (sysctl_tcp_cookie_size > 0) {
/* Default, cookies without s_data_payload. */
tp->cookie_values =
kzalloc(sizeof(*tp->cookie_values),
sk->sk_allocation);
if (tp->cookie_values != NULL)
kref_init(&tp->cookie_values->kref);
}
/* Presumed zeroed, in order of appearance:
* cookie_in_always, cookie_out_never,
* s_data_constant, s_data_in, s_data_out
*/
sk->sk_sndbuf = sysctl_tcp_wmem[1];
sk->sk_rcvbuf = sysctl_tcp_rmem[1];
local_bh_disable();
sock_update_memcg(sk);
sk_sockets_allocated_inc(sk);
local_bh_enable();
return 0; return 0;
} }