shuffle how the protocol family input is done in ether_input.

the main change is to defer chopping the ethernet header off until the
ether_type is looked at. the main advantage of this is pppoe doesn't have
to reattach the ether header anymore, which simplifies the code a lot.

ok mpi@ visa@ bluhm@

diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index d562dad..8f7d8e7 100644 (file)
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_ethersubr.c,v 1.249 2018/01/09 06:24:15 dlg Exp $  */
+/*     $OpenBSD: if_ethersubr.c,v 1.250 2018/01/10 00:14:38 dlg Exp $  */
 /*     $NetBSD: if_ethersubr.c,v 1.19 1996/05/07 02:40:30 thorpej Exp $        */
 
 /*
@@ -315,12 +315,9 @@ int
 ether_input(struct ifnet *ifp, struct mbuf *m, void *cookie)
 {
        struct ether_header *eh;
-       struct niqueue *inq;
+       void (*input)(struct ifnet *, struct mbuf *);
        u_int16_t etype;
        struct arpcom *ac;
-#if NPPPOE > 0
-       struct ether_header *eh_tmp;
-#endif
 
        /* Drop short frames */
        if (m->m_len < ETHER_HDR_LEN)
@@ -328,7 +325,6 @@ ether_input(struct ifnet *ifp, struct mbuf *m, void *cookie)
 
        ac = (struct arpcom *)ifp;
        eh = mtod(m, struct ether_header *);
-       m_adj(m, ETHER_HDR_LEN);
 
        if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
                /*
@@ -376,45 +372,34 @@ ether_input(struct ifnet *ifp, struct mbuf *m, void *cookie)
 
        switch (etype) {
        case ETHERTYPE_IP:
-               ipv4_input(ifp, m);
-               return (1);
+               input = ipv4_input;
+               break;
 
        case ETHERTYPE_ARP:
                if (ifp->if_flags & IFF_NOARP)
                        goto dropanyway;
-               arpinput(ifp, m);
-               return (1);
+               input = arpinput;
+               break;
 
        case ETHERTYPE_REVARP:
                if (ifp->if_flags & IFF_NOARP)
                        goto dropanyway;
-               revarpinput(ifp, m);
-               return (1);
+               input = revarpinput;
+               break;
 
 #ifdef INET6
        /*
         * Schedule IPv6 software interrupt for incoming IPv6 packet.
         */
        case ETHERTYPE_IPV6:
-               ipv6_input(ifp, m);
-               return (1);
+               input = ipv6_input;
+               break;
 #endif /* INET6 */
 #if NPPPOE > 0 || defined(PIPEX)
        case ETHERTYPE_PPPOEDISC:
        case ETHERTYPE_PPPOE:
                if (m->m_flags & (M_MCAST | M_BCAST))
                        goto dropanyway;
-               M_PREPEND(m, sizeof(*eh), M_DONTWAIT);
-               if (m == NULL)
-                       return (1);
-
-               eh_tmp = mtod(m, struct ether_header *);
-               /*
-                * danger!
-                * eh_tmp and eh may overlap because eh
-                * is stolen from the mbuf above.
-                */
-               memmove(eh_tmp, eh, sizeof(struct ether_header));
 #ifdef PIPEX
                if (pipex_enable) {
                        struct pipex_session *session;
@@ -426,22 +411,23 @@ ether_input(struct ifnet *ifp, struct mbuf *m, void *cookie)
                }
 #endif
                if (etype == ETHERTYPE_PPPOEDISC)
-                       inq = &pppoediscinq;
+                       niq_enqueue(&pppoediscinq, m);
                else
-                       inq = &pppoeinq;
-               break;
+                       niq_enqueue(&pppoeinq, m);
+               return (1);
 #endif
 #ifdef MPLS
        case ETHERTYPE_MPLS:
        case ETHERTYPE_MPLS_MCAST:
-               mpls_input(ifp, m);
-               return (1);
+               input = mpls_input;
+               break;
 #endif
        default:
                goto dropanyway;
        }
 
-       niq_enqueue(inq, m);
+       m_adj(m, sizeof(*eh));
+       (*input)(ifp, m);
        return (1);
 dropanyway:
        m_freem(m);