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Message-Id: <201001172127.03713.opurdila@ixiacom.com>
Date: Sun, 17 Jan 2010 21:27:03 +0200
From: Octavian Purdila <opurdila@...acom.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, mpyatkovskiy@...acom.com
Subject: Re: [PATCH] tcp: account SYN-ACK timeouts & retransmissions
On Thursday 14 January 2010 12:03:22 you wrote:
> From: Octavian Purdila <opurdila@...acom.com>
> Date: Wed, 13 Jan 2010 23:07:59 +0200
>
> > I think we lost the SynAck accounting with this commit from the
> > netdev-vger- cvs tree, where tcp_syn_recv_timer was introduced:
> >
> > commit 2248761e5cfcb8687563b29c77064185e7604947
> > Author: davem <davem>
> > Date: Sun Nov 10 21:25:00 1996 +0000
> >
> > Merge to 2.1.8, IPV6 is here. Also fix
> > a stupid bug in the kernel unaligned trap handler
> > where st %g0, [foo] would fail miserably.
> >
> >
> > Before this, both Syns and SynAcks seems to be accounted for.
>
> I'm convinced.
>
> Please spin your patch with the "doing TCP socket specific
> stuff in generic inet connection socket code" part fixed.
>
Hi David,
Here it is. I've based this against net-next since it is more intrusive then the original one. I can rebase it against net-2.6 if you think it can make it there.
Also, please let me know if you think I should split it up (maybe is worth having syn_ack_timeout in a separate patch, but to me it looks too small).
[net-next PATCH v2] tcp: account SYN-ACK timeouts & retransmissions
Currently we don't increment SYN-ACK timeouts & retransmissions
although we do increment the same stats for SYN. We seem to have lost
the SYN-ACK accounting with the introduction of tcp_syn_recv_timer
(commit 2248761e in the netdev-vger-cvs tree).
This patch fixes this issue. In the process we also rename the v4/v6
syn/ack retransmit functions for clarity. We also add a new
request_socket operations (syn_ack_timeout) so we can keep code in
inet_connection_sock.c protocol agnostic.
Signed-off-by: Octavian Purdila <opurdila@...acom.com>
---
include/net/request_sock.h | 2 ++
include/net/tcp.h | 2 ++
net/ipv4/inet_connection_sock.c | 2 ++
net/ipv4/tcp_ipv4.c | 18 ++++++++++--------
net/ipv4/tcp_timer.c | 6 ++++++
net/ipv6/tcp_ipv6.c | 12 ++++++++++--
6 files changed, 32 insertions(+), 10 deletions(-)
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index c9b50eb..99e6e19 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -45,6 +45,8 @@ struct request_sock_ops {
void (*send_reset)(struct sock *sk,
struct sk_buff *skb);
void (*destructor)(struct request_sock *req);
+ void (*syn_ack_timeout)(struct sock *sk,
+ struct request_sock *req);
};
/* struct request_sock - mini sock to represent a connection request
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 788c99f..87d164b 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -400,6 +400,8 @@ extern int compat_tcp_setsockopt(struct sock *sk,
int level, int optname,
char __user *optval, unsigned int optlen);
extern void tcp_set_keepalive(struct sock *sk, int val);
+extern void tcp_syn_ack_timeout(struct sock *sk,
+ struct request_sock *req);
extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg,
size_t len, int nonblock,
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index ee16475..8da6429 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -529,6 +529,8 @@ void inet_csk_reqsk_queue_prune(struct sock *parent,
syn_ack_recalc(req, thresh, max_retries,
queue->rskq_defer_accept,
&expire, &resend);
+ if (req->rsk_ops->syn_ack_timeout)
+ req->rsk_ops->syn_ack_timeout(parent, req);
if (!expire &&
(!resend ||
!req->rsk_ops->rtx_syn_ack(parent, req, NULL) ||
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 382f667..356f544 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -742,9 +742,9 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
* This still operates on a request_sock only, not on a big
* socket.
*/
-static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
- struct request_sock *req,
- struct request_values *rvp)
+static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
+ struct request_sock *req,
+ struct request_values *rvp)
{
const struct inet_request_sock *ireq = inet_rsk(req);
int err = -1;
@@ -775,10 +775,11 @@ static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
return err;
}
-static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
+static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
struct request_values *rvp)
{
- return __tcp_v4_send_synack(sk, NULL, req, rvp);
+ TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
+ return tcp_v4_send_synack(sk, NULL, req, rvp);
}
/*
@@ -1192,10 +1193,11 @@ static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
struct request_sock_ops tcp_request_sock_ops __read_mostly = {
.family = PF_INET,
.obj_size = sizeof(struct tcp_request_sock),
- .rtx_syn_ack = tcp_v4_send_synack,
+ .rtx_syn_ack = tcp_v4_rtx_synack,
.send_ack = tcp_v4_reqsk_send_ack,
.destructor = tcp_v4_reqsk_destructor,
.send_reset = tcp_v4_send_reset,
+ .syn_ack_timeout = tcp_syn_ack_timeout,
};
#ifdef CONFIG_TCP_MD5SIG
@@ -1373,8 +1375,8 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
}
tcp_rsk(req)->snt_isn = isn;
- if (__tcp_v4_send_synack(sk, dst, req,
- (struct request_values *)&tmp_ext) ||
+ if (tcp_v4_send_synack(sk, dst, req,
+ (struct request_values *)&tmp_ext) ||
want_cookie)
goto drop_and_free;
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 8816a20..de7d1bf 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -474,6 +474,12 @@ static void tcp_synack_timer(struct sock *sk)
TCP_TIMEOUT_INIT, TCP_RTO_MAX);
}
+void tcp_syn_ack_timeout(struct sock *sk, struct request_sock *req)
+{
+ NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPTIMEOUTS);
+}
+EXPORT_SYMBOL(tcp_syn_ack_timeout);
+
void tcp_set_keepalive(struct sock *sk, int val)
{
if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 1c832bf..82f2dea 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -520,6 +520,13 @@ done:
return err;
}
+static int tcp_v6_rtx_synack(struct sock *sk, struct request_sock *req,
+ struct request_values *rvp)
+{
+ TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
+ return tcp_v6_send_synack(sk, req, rvp);
+}
+
static inline void syn_flood_warning(struct sk_buff *skb)
{
#ifdef CONFIG_SYN_COOKIES
@@ -890,10 +897,11 @@ static int tcp_v6_inbound_md5_hash (struct sock *sk, struct sk_buff *skb)
struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
.family = AF_INET6,
.obj_size = sizeof(struct tcp6_request_sock),
- .rtx_syn_ack = tcp_v6_send_synack,
+ .rtx_syn_ack = tcp_v6_rtx_synack,
.send_ack = tcp_v6_reqsk_send_ack,
.destructor = tcp_v6_reqsk_destructor,
- .send_reset = tcp_v6_send_reset
+ .send_reset = tcp_v6_send_reset,
+ .syn_ack_timeout = tcp_syn_ack_timeout,
};
#ifdef CONFIG_TCP_MD5SIG
--
1.5.6.5
--
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