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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-03-19 05:37:18 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-03-21 18:31:35 -0700 |
| commit | 907cdda5205b012eec7513f66713749b293188c9 (patch) | |
| tree | 0488e7282c2d3748d90f8ceca78a183f905c4167 | |
| parent | 32a806c194ea112cfab00f558482dd97bee5e44e (diff) | |
| download | linux-3.10-907cdda5205b012eec7513f66713749b293188c9.tar.gz linux-3.10-907cdda5205b012eec7513f66713749b293188c9.tar.bz2 linux-3.10-907cdda5205b012eec7513f66713749b293188c9.zip | |
tcp: Add SNMP counter for DEFER_ACCEPT
Its currently hard to diagnose when ACK frames are dropped because an
application set TCP_DEFER_ACCEPT on its listening socket.
See http://bugzilla.kernel.org/show_bug.cgi?id=15507
This patch adds a SNMP value, named TCPDeferAcceptDrop
netstat -s | grep TCPDeferAcceptDrop
TCPDeferAcceptDrop: 0
This counter is incremented every time we drop a pure ACK frame received
by a socket in SYN_RECV state because its SYNACK retrans count is lower
than defer_accept value.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/snmp.h | 1 | ||||
| -rw-r--r-- | net/ipv4/proc.c | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp_minisocks.c | 1 |
3 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/snmp.h b/include/linux/snmp.h index 4435d108475..d2a9aa3c6c8 100644 --- a/include/linux/snmp.h +++ b/include/linux/snmp.h @@ -227,6 +227,7 @@ enum LINUX_MIB_SACKSHIFTFALLBACK, LINUX_MIB_TCPBACKLOGDROP, LINUX_MIB_TCPMINTTLDROP, /* RFC 5082 */ + LINUX_MIB_TCPDEFERACCEPTDROP, __LINUX_MIB_MAX }; diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 4f1f337f433..3dc9914c1dc 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -251,6 +251,7 @@ static const struct snmp_mib snmp4_net_list[] = { SNMP_MIB_ITEM("TCPSackShiftFallback", LINUX_MIB_SACKSHIFTFALLBACK), SNMP_MIB_ITEM("TCPBacklogDrop", LINUX_MIB_TCPBACKLOGDROP), SNMP_MIB_ITEM("TCPMinTTLDrop", LINUX_MIB_TCPMINTTLDROP), + SNMP_MIB_ITEM("TCPDeferAcceptDrop", LINUX_MIB_TCPDEFERACCEPTDROP), SNMP_MIB_SENTINEL }; diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 4199bc6915c..32f96278a24 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -671,6 +671,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, if (req->retrans < inet_csk(sk)->icsk_accept_queue.rskq_defer_accept && TCP_SKB_CB(skb)->end_seq == tcp_rsk(req)->rcv_isn + 1) { inet_rsk(req)->acked = 1; + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPDEFERACCEPTDROP); return NULL; } |