Subject: Re: Fix "ipOutNoRoutes" counter error for TCP and UDP

From: weidong <[email-masked]>
Date: Wed, 25 Apr 2007 15:39:55 +0800

Hi Mr. David
    I have modified my patch according to you advice. I think -
EHOSTUNREACH
is only for "input path". In "output" path, we can just simply check
-ENETUNREACH  (^_^), the patch is shown in the end of this mail.

BTW: my E-mail has been changed to [email-masked]

>> >> Function need to fix:
>> >> tcp_v4_connect(); ip4_datagram_connect(); udp_sendmsg();
>>

> > I think we need to make these checks more carefully.
> >
> > Route lookup can fail for several reasons other than
> > no route being available.  Two examples are:
> >
> > 1) Out of memory error while creating route
> > 2) IPSEC disallows communication to that flow ID
> >
> > As a result, we'll probably best limiting the counter
> > increment when the error is either -EHOSTUNREACH or
> > -ENETUNREACH.
>

signed-off-by: Wei Dong <[email-masked]>

diff -ruNp a/net/ipv4/datagram.c b/net/ipv4/datagram.c
--- a/net/ipv4/datagram.c	2007-04-25 15:20:19.000000000 +0800
+++ b/net/ipv4/datagram.c	2007-04-25 15:21:42.000000000 +0800
@@ -50,8 +50,12 @@ int ip4_datagram_connect(struct sock *sk
 			       RT_CONN_FLAGS(sk), oif,
 			       sk->sk_protocol,
 			       inet->sport, usin->sin_port, sk);
-	if (err)
+	if (err) {
+		if (err == -ENETUNREACH)
+			IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
 		return err;
+	}
+
 	if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, SOCK_BROADCAST)) {
 		ip_rt_put(rt);
 		return -EACCES;
diff -ruNp a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
--- a/net/ipv4/tcp_ipv4.c	2007-04-25 15:20:19.000000000 +0800
+++ b/net/ipv4/tcp_ipv4.c	2007-04-25 15:21:42.000000000 +0800
@@ -192,8 +192,11 @@ int tcp_v4_connect(struct sock *sk, stru
 			       RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
 			       IPPROTO_TCP,
 			       inet->sport, usin->sin_port, sk);
-	if (tmp < 0)
+	if (tmp < 0) {
+		if (tmp == -ENETUNREACH)
+			IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
 		return tmp;
+	}

 	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
 		ip_rt_put(rt);
diff -ruNp a/net/ipv4/udp.c b/net/ipv4/udp.c
--- a/net/ipv4/udp.c	2007-04-25 15:20:19.000000000 +0800
+++ b/net/ipv4/udp.c	2007-04-25 15:21:42.000000000 +0800
@@ -630,8 +630,11 @@ int udp_sendmsg(struct kiocb *iocb, stru
 						 .dport = dport } } };
 		security_sk_classify_flow(sk, &fl);
 		err = ip_route_output_flow(&rt, &fl, sk, !(msg->msg_flags&MSG_DONTWAIT));
-		if (err)
+		if (err) {
+			if (err == -ENETUNREACH)
+				IP_INC_STATS_BH(IPSTATS_MIB_OUTNOROUTES);
 			goto out;
+		}

 		err = -EACCES;
 		if ((rt->rt_flags & RTCF_BROADCAST) &&