[PATCH] Export accept queue len of a TCP listening socket via /proc/net/tcp{6}
From: Sridhar Samudrala <hidden>
Date: 2006-06-21 23:57:38
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
While debugging a TCP server hang issue, we noticed that currently there is no way for a user to find the acceptq backlog value for a TCP listen socket. All the standard networking utilities that display socket info like netstat, ss and /proc/net/tcp have 2 fields called rx_queue and tx_queue. I think these fields do not mean much for listening sockets and they are always zero. So why not use one of these fields(rx_queue) to export the accept queue len for listening sockets? The attached patch implements this, but it only works with /proc/net/tcp and /proc/net/tcp6. In order to support this with netstat/ss that use netlink mechanism to get the socket info, i think we need to extend tcp_info to add this field. Can this be done in a backward compatible way? Anyway, i think it is useful to have this value exported via /proc. Thanks Sridhar Signed-off-by: Sridhar Samudrala <redacted>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 25ecc6e..4c6ef47 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -1726,7 +1726,8 @@ static void get_tcp4_sock(struct sock *s sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " "%08X %5d %8d %lu %d %p %u %u %u %u %d", i, src, srcp, dest, destp, sp->sk_state, - tp->write_seq - tp->snd_una, tp->rcv_nxt - tp->copied_seq, + tp->write_seq - tp->snd_una, + (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq), timer_active, jiffies_to_clock_t(timer_expires - jiffies), icsk->icsk_retransmits,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index a50eb30..b36d5b2 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c@@ -1469,7 +1469,8 @@ static void get_tcp6_sock(struct seq_fil dest->s6_addr32[0], dest->s6_addr32[1], dest->s6_addr32[2], dest->s6_addr32[3], destp, sp->sk_state, - tp->write_seq-tp->snd_una, tp->rcv_nxt-tp->copied_seq, + tp->write_seq-tp->snd_una, + (sp->sk_state == TCP_LISTEN) ? sp->sk_ack_backlog : (tp->rcv_nxt - tp->copied_seq), timer_active, jiffies_to_clock_t(timer_expires - jiffies), icsk->icsk_retransmits,