diff options
| author | Julian Anastasov <ja@ssi.bg> | 2009-10-19 12:10:40 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-10-20 04:19:06 +0200 |
| commit | b103cf34382f26ff48a87931b83f13b177b47c1a (patch) | |
| tree | 6922379bca3fc9935d394bc474a91b859ac06813 /net | |
| parent | tcp: reduce SYN-ACK retrans for TCP_DEFER_ACCEPT (diff) | |
| download | linux-b103cf34382f26ff48a87931b83f13b177b47c1a.tar.xz linux-b103cf34382f26ff48a87931b83f13b177b47c1a.zip | |
tcp: fix TCP_DEFER_ACCEPT retrans calculation
Fix TCP_DEFER_ACCEPT conversion between seconds and
retransmission to match the TCP SYN-ACK retransmission periods
because the time is converted to such retransmissions. The old
algorithm selects one more retransmission in some cases. Allow
up to 255 retransmissions.
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp.c | 55 |
1 files changed, 43 insertions, 12 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 64d0af675823..9b2756fbdf9b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -326,6 +326,43 @@ void tcp_enter_memory_pressure(struct sock *sk) EXPORT_SYMBOL(tcp_enter_memory_pressure); +/* Convert seconds to retransmits based on initial and max timeout */ +static u8 secs_to_retrans(int seconds, int timeout, int rto_max) +{ + u8 res = 0; + + if (seconds > 0) { + int period = timeout; + + res = 1; + while (seconds > period && res < 255) { + res++; + timeout <<= 1; + if (timeout > rto_max) + timeout = rto_max; + period += timeout; + } + } + return res; +} + +/* Convert retransmits to seconds based on initial and max timeout */ +static int retrans_to_secs(u8 retrans, int timeout, int rto_max) +{ + int period = 0; + + if (retrans > 0) { + period = timeout; + while (--retrans) { + timeout <<= 1; + if (timeout > rto_max) + timeout = rto_max; + period += timeout; + } + } + return period; +} + /* * Wait for a TCP event. * @@ -2163,16 +2200,10 @@ static int do_tcp_setsockopt(struct sock *sk, int level, break; case TCP_DEFER_ACCEPT: - icsk->icsk_accept_queue.rskq_defer_accept = 0; - if (val > 0) { - /* Translate value in seconds to number of - * retransmits */ - while (icsk->icsk_accept_queue.rskq_defer_accept < 32 && - val > ((TCP_TIMEOUT_INIT / HZ) << - icsk->icsk_accept_queue.rskq_defer_accept)) - icsk->icsk_accept_queue.rskq_defer_accept++; - icsk->icsk_accept_queue.rskq_defer_accept++; - } + /* Translate value in seconds to number of retransmits */ + icsk->icsk_accept_queue.rskq_defer_accept = + secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ, + TCP_RTO_MAX / HZ); break; case TCP_WINDOW_CLAMP: @@ -2353,8 +2384,8 @@ static int do_tcp_getsockopt(struct sock *sk, int level, val = (val ? : sysctl_tcp_fin_timeout) / HZ; break; case TCP_DEFER_ACCEPT: - val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 : - ((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1)); + val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept, + TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ); break; case TCP_WINDOW_CLAMP: val = tp->window_clamp; |