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authorJulian Anastasov <ja@ssi.bg>2009-10-19 10:10:40 +0000
committerDavid S. Miller <davem@davemloft.net>2009-10-19 19:19:06 -0700
commitb103cf34382f26ff48a87931b83f13b177b47c1a (patch)
tree6922379bca3fc9935d394bc474a91b859ac06813 /net
parent0c3d79bce48034018e840468ac5a642894a521a3 (diff)
downloadlinux-b103cf34382f26ff48a87931b83f13b177b47c1a.tar.gz
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.c55
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;