This change re-adds L2 caching for TCP and UDP, as originally added in D4306

but removed due to other changes in the system. Restore the llentry pointer
to the "struct route", and use it to cache the L2 lookup (ARP or ND6) as
appropriate.

Submitted by:	Mike Karels
Differential Revision:	https://reviews.freebsd.org/D6262

1 files changed, 40 insertions, 7 deletions

diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 6f0e6e3cc177..9346aecb9f82 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -199,7 +199,7 @@ ether_requestencap(struct ifnet *ifp, struct if_encap_req *req)
 static int
 ether_resolve_addr(struct ifnet *ifp, struct mbuf *m,
 	const struct sockaddr *dst, struct route *ro, u_char *phdr,
-	uint32_t *pflags)
+	uint32_t *pflags, struct llentry **plle)
 {
 	struct ether_header *eh;
 	uint32_t lleflags = 0;
@@ -208,13 +208,16 @@ ether_resolve_addr(struct ifnet *ifp, struct mbuf *m,
 	uint16_t etype;
 #endif
 
+	if (plle)
+		*plle = NULL;
 	eh = (struct ether_header *)phdr;
 
 	switch (dst->sa_family) {
 #ifdef INET
 	case AF_INET:
 		if ((m->m_flags & (M_BCAST | M_MCAST)) == 0)
-			error = arpresolve(ifp, 0, m, dst, phdr, &lleflags);
+			error = arpresolve(ifp, 0, m, dst, phdr, &lleflags,
+			    plle);
 		else {
 			if (m->m_flags & M_BCAST)
 				memcpy(eh->ether_dhost, ifp->if_broadcastaddr,
@@ -233,7 +236,8 @@ ether_resolve_addr(struct ifnet *ifp, struct mbuf *m,
 #ifdef INET6
 	case AF_INET6:
 		if ((m->m_flags & M_MCAST) == 0)
-			error = nd6_resolve(ifp, 0, m, dst, phdr, &lleflags);
+			error = nd6_resolve(ifp, 0, m, dst, phdr, &lleflags,
+			    plle);
 		else {
 			const struct in6_addr *a6;
 			a6 = &(((const struct sockaddr_in6 *)dst)->sin6_addr);
@@ -283,14 +287,40 @@ ether_output(struct ifnet *ifp, struct mbuf *m,
 	int loop_copy = 1;
 	int hlen;	/* link layer header length */
 	uint32_t pflags;
+	struct llentry *lle = NULL;
+	struct rtentry *rt0 = NULL;
+	int addref = 0;
 
 	phdr = NULL;
 	pflags = 0;
 	if (ro != NULL) {
-		phdr = ro->ro_prepend;
-		hlen = ro->ro_plen;
-		pflags = ro->ro_flags;
+		/* XXX BPF uses ro_prepend */
+		if (ro->ro_prepend != NULL) {
+			phdr = ro->ro_prepend;
+			hlen = ro->ro_plen;
+		} else if (!(m->m_flags & (M_BCAST | M_MCAST))) {
+			if ((ro->ro_flags & RT_LLE_CACHE) != 0) {
+				lle = ro->ro_lle;
+				if (lle != NULL &&
+				    (lle->la_flags & LLE_VALID) == 0) {
+					LLE_FREE(lle);
+					lle = NULL;	/* redundant */
+					ro->ro_lle = NULL;
+				}
+				if (lle == NULL) {
+					/* if we lookup, keep cache */
+					addref = 1;
+				}
+			}
+			if (lle != NULL) {
+				phdr = lle->r_linkdata;
+				hlen = lle->r_hdrlen;
+				pflags = lle->r_flags;
+			}
+		}
+		rt0 = ro->ro_rt;
 	}
+
 #ifdef MAC
 	error = mac_ifnet_check_transmit(ifp, m);
 	if (error)
@@ -308,7 +338,10 @@ ether_output(struct ifnet *ifp, struct mbuf *m,
 		/* No prepend data supplied. Try to calculate ourselves. */
 		phdr = linkhdr;
 		hlen = ETHER_HDR_LEN;
-		error = ether_resolve_addr(ifp, m, dst, ro, phdr, &pflags);
+		error = ether_resolve_addr(ifp, m, dst, ro, phdr, &pflags,
+		    addref ? &lle : NULL);
+		if (addref && lle != NULL)
+			ro->ro_lle = lle;
 		if (error != 0)
 			return (error == EWOULDBLOCK ? 0 : error);
 	}