Messages in this thread Patch in this message | | | Date | Fri, 19 Nov 2010 13:56:33 -0800 | From | Greg KH <> | Subject | [72/82] net-2.6: SYN retransmits: Add new parameter to retransmits_timed_out() |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: Damian Lukowski <damian@tvk.rwth-aachen.de>
[ Upstream commit 4d22f7d372f5769c6c0149e427ed6353e2dcfe61 ]
Fixes kernel Bugzilla Bug 18952
This patch adds a syn_set parameter to the retransmits_timed_out() routine and updates its callers. If not set, TCP_RTO_MIN is taken as the calculation basis as before. If set, TCP_TIMEOUT_INIT is used instead, so that sysctl_syn_retries represents the actual amount of SYN retransmissions in case no SYNACKs are received when establishing a new connection.
Signed-off-by: Damian Lukowski <damian@tvk.rwth-aachen.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- net/ipv4/tcp_timer.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)
--- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -136,13 +136,16 @@ static void tcp_mtu_probing(struct inet_ /* This function calculates a "timeout" which is equivalent to the timeout of a * TCP connection after "boundary" unsuccessful, exponentially backed-off - * retransmissions with an initial RTO of TCP_RTO_MIN. + * retransmissions with an initial RTO of TCP_RTO_MIN or TCP_TIMEOUT_INIT if + * syn_set flag is set. */ static bool retransmits_timed_out(struct sock *sk, - unsigned int boundary) + unsigned int boundary, + bool syn_set) { unsigned int timeout, linear_backoff_thresh; unsigned int start_ts; + unsigned int rto_base = syn_set ? TCP_TIMEOUT_INIT : TCP_RTO_MIN; if (!inet_csk(sk)->icsk_retransmits) return false; @@ -152,12 +155,12 @@ static bool retransmits_timed_out(struct else start_ts = tcp_sk(sk)->retrans_stamp; - linear_backoff_thresh = ilog2(TCP_RTO_MAX/TCP_RTO_MIN); + linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base); if (boundary <= linear_backoff_thresh) - timeout = ((2 << boundary) - 1) * TCP_RTO_MIN; + timeout = ((2 << boundary) - 1) * rto_base; else - timeout = ((2 << linear_backoff_thresh) - 1) * TCP_RTO_MIN + + timeout = ((2 << linear_backoff_thresh) - 1) * rto_base + (boundary - linear_backoff_thresh) * TCP_RTO_MAX; return (tcp_time_stamp - start_ts) >= timeout; @@ -168,14 +171,15 @@ static int tcp_write_timeout(struct sock { struct inet_connection_sock *icsk = inet_csk(sk); int retry_until; - bool do_reset; + bool do_reset, syn_set = 0; if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { if (icsk->icsk_retransmits) dst_negative_advice(sk); retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; + syn_set = 1; } else { - if (retransmits_timed_out(sk, sysctl_tcp_retries1)) { + if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0)) { /* Black hole detection */ tcp_mtu_probing(icsk, sk); @@ -188,14 +192,14 @@ static int tcp_write_timeout(struct sock retry_until = tcp_orphan_retries(sk, alive); do_reset = alive || - !retransmits_timed_out(sk, retry_until); + !retransmits_timed_out(sk, retry_until, 0); if (tcp_out_of_resources(sk, do_reset)) return 1; } } - if (retransmits_timed_out(sk, retry_until)) { + if (retransmits_timed_out(sk, retry_until, syn_set)) { /* Has it gone just too far? */ tcp_write_err(sk); return 1; @@ -437,7 +441,7 @@ out_reset_timer: icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX); } inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX); - if (retransmits_timed_out(sk, sysctl_tcp_retries1 + 1)) + if (retransmits_timed_out(sk, sysctl_tcp_retries1 + 1, 0)) __sk_dst_reset(sk); out:;
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