If TSO is enabled, fix the IPv6 forward counters and icmp6 redirect.

First try to send with TSO.  The goto senderr handles icmp6 redirect
and other errors.  If TSO is not necessary and the interface MTU
fits, just send the packet.  Again goto senderr handles icmp6.
Finally care about icmp6 packet too big.

tested and OK jan@

diff --git a/sys/netinet6/ip6_forward.c b/sys/netinet6/ip6_forward.c
index 85a7e91..db68b32 100644 (file)
--- a/sys/netinet6/ip6_forward.c
+++ b/sys/netinet6/ip6_forward.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ip6_forward.c,v 1.110 2023/06/01 09:05:33 jan Exp $   */
+/*     $OpenBSD: ip6_forward.c,v 1.111 2023/06/16 19:18:56 bluhm Exp $ */
 /*     $KAME: ip6_forward.c,v 1.75 2001/06/29 12:42:13 jinmei Exp $    */
 
 /*
@@ -321,35 +321,30 @@ reroute:
 
        error = tcp_if_output_tso(ifp, &m, sin6tosa(sin6), rt, IFCAP_TSOv6,
            ifp->if_mtu);
+       if (error)
+               ip6stat_inc(ip6s_cantforward);
+       else if (m == NULL)
+               ip6stat_inc(ip6s_forward);
        if (error || m == NULL)
-               goto freecopy;
+               goto senderr;
 
        /* Check the size after pf_test to give pf a chance to refragment. */
-       if (m->m_pkthdr.len > ifp->if_mtu) {
-               if (mcopy)
-                       icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0,
-                           ifp->if_mtu);
-               m_freem(m);
-               goto out;
+       if (m->m_pkthdr.len <= ifp->if_mtu) {
+               in6_proto_cksum_out(m, ifp);
+               error = ifp->if_output(ifp, m, sin6tosa(sin6), rt);
+               if (error)
+                       ip6stat_inc(ip6s_cantforward);
+               else
+                       ip6stat_inc(ip6s_forward);
+               goto senderr;
        }
 
-       in6_proto_cksum_out(m, ifp);
-       error = ifp->if_output(ifp, m, sin6tosa(sin6), rt);
-       if (error) {
-               ip6stat_inc(ip6s_cantforward);
-       } else {
-               ip6stat_inc(ip6s_forward);
-               if (type)
-                       ip6stat_inc(ip6s_redirectsent);
-               else {
-                       if (mcopy)
-                               goto freecopy;
-               }
-       }
+       if (mcopy != NULL)
+               icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, ifp->if_mtu);
+       m_freem(m);
+       goto out;
 
-#if NPF > 0 || defined(IPSEC)
 senderr:
-#endif
        if (mcopy == NULL)
                goto out;
 
@@ -357,6 +352,7 @@ senderr:
        case 0:
                if (type == ND_REDIRECT) {
                        icmp6_redirect_output(mcopy, rt);
+                       ip6stat_inc(ip6s_redirectsent);
                        goto out;
                }
                goto freecopy;