FreeBSD previously provided route caching for TCP (and UDP). Re-add

route caching for TCP, with some improvements. In particular, invalidate
the route cache if a new route is added, which might be a better match.
The cache is automatically invalidated if the old route is deleted.

Submitted by:	Mike Karels
Reviewed by:	gnn
Differential Revision:	https://reviews.freebsd.org/D4306

3 files changed, 27 insertions, 11 deletions

diff --git a/sys/netinet6/in6_pcb.c b/sys/netinet6/in6_pcb.c
index a779b8d..98f4cd3 100644
--- a/sys/netinet6/in6_pcb.c
+++ b/sys/netinet6/in6_pcb.c
@@ -827,9 +827,10 @@ void
 in6_losing(struct inpcb *in6p)
 {
 
-	/*
-	 * We don't store route pointers in the routing table anymore
-	 */
+	if (in6p->inp_route6.ro_rt) {
+		RTFREE(in6p->inp_route6.ro_rt);
+		in6p->inp_route6.ro_rt = (struct rtentry *)NULL;
+	}
 	return;
 }
 
@@ -840,9 +841,11 @@ in6_losing(struct inpcb *in6p)
 struct inpcb *
 in6_rtchange(struct inpcb *inp, int errno)
 {
-	/*
-	 * We don't store route pointers in the routing table anymore
-	 */
+
+	if (inp->inp_route6.ro_rt) {
+		RTFREE(inp->inp_route6.ro_rt);
+		inp->inp_route6.ro_rt = (struct rtentry *)NULL;
+	}
 	return inp;
 }
 
diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index 3a47285..7895139 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -546,7 +546,18 @@ again:
 	/* adjust pointer */
 	ip6 = mtod(m, struct ip6_hdr *);
 
-	if (ro->ro_rt && fwd_tag == NULL) {
+	/*
+	 * Validate route against routing table additions;
+	 * a better/more specific route might have been added.
+	 * Make sure address family is set in route.
+	 */
+	if (inp) {
+		ro->ro_dst.sin6_family = AF_INET6;
+		RT_VALIDATE((struct route *)ro, &inp->inp_rt_cookie, fibnum);
+	}
+	if (ro->ro_rt && fwd_tag == NULL && (ro->ro_rt->rt_flags & RTF_UP) &&
+	    ro->ro_dst.sin6_family == AF_INET6 &&
+	    IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &ip6->ip6_dst)) {
 		rt = ro->ro_rt;
 		ifp = ro->ro_rt->rt_ifp;
 	} else {
@@ -939,7 +950,8 @@ passout:
 			    m->m_pkthdr.len);
 			ifa_free(&ia6->ia_ifa);
 		}
-		error = nd6_output_ifp(ifp, origifp, m, dst, NULL);
+		error = nd6_output_ifp(ifp, origifp, m, dst,
+		    (struct route *)ro);
 		goto done;
 	}
 
@@ -1038,7 +1050,8 @@ sendorfree:
 				counter_u64_add(ia->ia_ifa.ifa_obytes,
 				    m->m_pkthdr.len);
 			}
-			error = nd6_output_ifp(ifp, origifp, m, dst, NULL);
+			error = nd6_output_ifp(ifp, origifp, m, dst,
+			    (struct route *)ro);
 		} else
 			m_freem(m);
 	}
diff --git a/sys/netinet6/udp6_usrreq.c b/sys/netinet6/udp6_usrreq.c
index 9768df5..ebcf6d6 100644
--- a/sys/netinet6/udp6_usrreq.c
+++ b/sys/netinet6/udp6_usrreq.c
@@ -876,8 +876,8 @@ udp6_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *addr6,
 
 		UDP_PROBE(send, NULL, inp, ip6, inp, udp6);
 		UDPSTAT_INC(udps_opackets);
-		error = ip6_output(m, optp, NULL, flags, inp->in6p_moptions,
-		    NULL, inp);
+		error = ip6_output(m, optp, &inp->inp_route6, flags,
+		    inp->in6p_moptions, NULL, inp);
 		break;
 	case AF_INET:
 		error = EAFNOSUPPORT;