Add support for actually sending WCCP return packets via GRE.

This MAY be combined by a clever person with the 'key' code recently
added, however a cursary glance suggest that it would be safer to just keep
the patches as it is unlikely that the two modes would be used together
and the separate patch has been extensively tested.

Obtained from:	 here and there
MFC after:	1 week

1 files changed, 9 insertions, 3 deletions

diff --git a/sys/net/if_gre.c b/sys/net/if_gre.c
index ea6c0c0..c3ec001 100644
--- a/sys/net/if_gre.c
+++ b/sys/net/if_gre.c
@@ -250,6 +250,7 @@ gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 	u_int16_t etype = 0;
 	struct mobile_h mob_h;
 	u_int32_t af;
+	int extra = 0;
 
 	/*
 	 * gre may cause infinite recursion calls when misconfigured.
@@ -365,7 +366,12 @@ gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 			ip = mtod(m, struct ip *);
 			gre_ip_tos = ip->ip_tos;
 			gre_ip_id = ip->ip_id;
-			etype = ETHERTYPE_IP;
+			if (sc->wccp_ver == WCCP_V2) {
+				extra = sizeof(uint32_t);
+				etype =  WCCP_PROTOCOL_TYPE;
+			} else {
+				etype = ETHERTYPE_IP;
+			}
 			break;
 #ifdef INET6
 		case AF_INET6:
@@ -386,7 +392,7 @@ gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 		}
 			
 		/* Reserve space for GRE header + optional GRE key */
-		int hdrlen = sizeof(struct greip);
+		int hdrlen = sizeof(struct greip) + extra;
 		if (sc->key)
 			hdrlen += sizeof(uint32_t);
 		M_PREPEND(m, hdrlen, M_DONTWAIT);
@@ -409,7 +415,7 @@ gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 	if (sc->g_proto == IPPROTO_GRE) {
 		uint32_t *options = gh->gi_options;
 
-		memset((void *)gh, 0, sizeof(struct greip));
+		memset((void *)gh, 0, sizeof(struct greip) + extra);
 		gh->gi_ptype = htons(etype);
 		gh->gi_flags = 0;