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

From: Wei Dong <[email-masked]>
Date: Thu, 31 May 2007 09:18:03 +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.

  I send this patch to you several weeks ago, but you have not replied to me.
This patch is not correctly?

 >>>>>>>> >>>> >> >> 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) &&