[src/trunk]: src/sys/net Style, and fix a bug in the AppleTalk path: we're doing

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/2fb17984b814
branches:  trunk
changeset: 829050:2fb17984b814
user:      maxv <maxv%NetBSD.org@localhost>
date:      Mon Jan 15 14:00:34 2018 +0000

description:
Style, and fix a bug in the AppleTalk path: we're doing
M_PREPEND(M_DONTWAIT), but we forgot to NULL-check the mbuf afterwards.

diffstat:

 sys/net/if_ethersubr.c |  53 +++++++++++++++++++++++++++++++------------------
 1 files changed, 33 insertions(+), 20 deletions(-)

diffs (183 lines):

diff -r b55bccf5690d -r 2fb17984b814 sys/net/if_ethersubr.c
--- a/sys/net/if_ethersubr.c    Mon Jan 15 13:14:18 2018 +0000
+++ b/sys/net/if_ethersubr.c    Mon Jan 15 14:00:34 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_ethersubr.c,v 1.255 2018/01/15 13:14:18 maxv Exp $  */
+/*     $NetBSD: if_ethersubr.c,v 1.256 2018/01/15 14:00:34 maxv Exp $  */
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -61,7 +61,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_ethersubr.c,v 1.255 2018/01/15 13:14:18 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_ethersubr.c,v 1.256 2018/01/15 14:00:34 maxv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -187,12 +187,11 @@
  */
 static int
 ether_output(struct ifnet * const ifp0, struct mbuf * const m0,
-       const struct sockaddr * const dst,
-       const struct rtentry *rt)
+    const struct sockaddr * const dst, const struct rtentry *rt)
 {
+       uint8_t esrc[ETHER_ADDR_LEN], edst[ETHER_ADDR_LEN];
        uint16_t etype = 0;
        int error = 0, hdrcmplt = 0;
-       uint8_t esrc[6], edst[6];
        struct mbuf *m = m0;
        struct mbuf *mcopy = NULL;
        struct ether_header *eh;
@@ -240,7 +239,7 @@
 #ifdef INET
        case AF_INET:
                if (m->m_flags & M_BCAST)
-                       (void)memcpy(edst, etherbroadcastaddr, sizeof(edst));
+                       memcpy(edst, etherbroadcastaddr, sizeof(edst));
                else if (m->m_flags & M_MCAST)
                        ETHER_MAP_IP_MULTICAST(&satocsin(dst)->sin_addr, edst);
                else if ((error = arpresolve(ifp, rt, m, dst, edst,
@@ -249,14 +248,14 @@
                }
                /* If broadcasting on a simplex interface, loopback a copy */
                if ((m->m_flags & M_BCAST) && (ifp->if_flags & IFF_SIMPLEX))
-                       mcopy = m_copy(m, 0, (int)M_COPYALL);
+                       mcopy = m_copy(m, 0, M_COPYALL);
                etype = htons(ETHERTYPE_IP);
                break;
 
        case AF_ARP:
                ah = mtod(m, struct arphdr *);
                if (m->m_flags & M_BCAST)
-                       (void)memcpy(edst, etherbroadcastaddr, sizeof(edst));
+                       memcpy(edst, etherbroadcastaddr, sizeof(edst));
                else {
                        void *tha = ar_tha(ah);
 
@@ -281,13 +280,13 @@
                default:
                        etype = htons(ETHERTYPE_ARP);
                }
-
                break;
 #endif
+
 #ifdef INET6
        case AF_INET6:
                if (m->m_flags & M_BCAST)
-                       (void)memcpy(edst, etherbroadcastaddr, sizeof(edst));
+                       memcpy(edst, etherbroadcastaddr, sizeof(edst));
                else if (m->m_flags & M_MCAST) {
                        ETHER_MAP_IPV6_MULTICAST(&satocsin6(dst)->sin6_addr,
                            edst);
@@ -300,19 +299,22 @@
                etype = htons(ETHERTYPE_IPV6);
                break;
 #endif
+
 #ifdef NETATALK
        case AF_APPLETALK: {
                struct ifaddr *ifa;
                int s;
 
                KERNEL_LOCK(1, NULL);
+
                if (!aarpresolve(ifp, m, (const struct sockaddr_at *)dst, edst)) {
 #ifdef NETATALKDEBUG
                        printf("aarpresolv failed\n");
-#endif /* NETATALKDEBUG */
+#endif
                        KERNEL_UNLOCK_ONE(NULL);
                        return (0);
                }
+
                /*
                 * ifaddr is the first thing in at_ifaddr
                 */
@@ -321,6 +323,7 @@
                if (ifa == NULL) {
                        pserialize_read_exit(s);
                        KERNEL_UNLOCK_ONE(NULL);
+                       /* XXX error? */
                        goto bad;
                }
                aa = (struct at_ifaddr *)ifa;
@@ -335,6 +338,11 @@
                        struct llc llc;
 
                        M_PREPEND(m, sizeof(struct llc), M_DONTWAIT);
+                       if (m == NULL) {
+                               KERNEL_UNLOCK_ONE(NULL);
+                               senderr(ENOBUFS);
+                       }
+
                        llc.llc_dsap = llc.llc_ssap = LLC_SNAP_LSAP;
                        llc.llc_control = LLC_UI;
                        memcpy(llc.llc_snap_org_code, at_org_code,
@@ -349,6 +357,7 @@
                break;
        }
 #endif /* NETATALK */
+
        case pseudo_AF_HDRCMPLT:
                hdrcmplt = 1;
                memcpy(esrc,
@@ -387,20 +396,24 @@
        if (mcopy)
                (void)looutput(ifp, mcopy, dst, rt);
 
-       /* If no ether type is set, this must be a 802.2 formatted packet.
+       KASSERT((m->m_flags & M_PKTHDR) != 0);
+
+       /*
+        * If no ether type is set, this must be a 802.2 formatted packet.
         */
        if (etype == 0)
                etype = htons(m->m_pkthdr.len);
+
        /*
-        * Add local net header.  If no space in first mbuf,
-        * allocate another.
+        * Add local net header. If no space in first mbuf, allocate another.
         */
-       M_PREPEND(m, sizeof (struct ether_header), M_DONTWAIT);
-       if (m == 0)
+       M_PREPEND(m, sizeof(struct ether_header), M_DONTWAIT);
+       if (m == NULL)
                senderr(ENOBUFS);
+
        eh = mtod(m, struct ether_header *);
        /* Note: etype is already in network byte order. */
-       (void)memcpy(&eh->ether_type, &etype, sizeof(eh->ether_type));
+       memcpy(&eh->ether_type, &etype, sizeof(eh->ether_type));
        memcpy(eh->ether_dhost, edst, sizeof(edst));
        if (hdrcmplt)
                memcpy(eh->ether_shost, esrc, sizeof(eh->ether_shost));
@@ -413,7 +426,7 @@
                memcpy(eh->ether_shost, CLLADDR(ifp0->if_sadl),
                    sizeof(eh->ether_shost));
        }
-#endif /* NCARP > 0 */
+#endif
 
        if ((error = pfil_run_hooks(ifp->if_pfil, &m, ifp, PFIL_OUT)) != 0)
                return (error);
@@ -425,13 +438,13 @@
         * Bridges require special output handling.
         */
        if (ifp->if_bridge)
-               return (bridge_output(ifp, m, NULL, NULL));
+               return bridge_output(ifp, m, NULL, NULL);
 #endif
 
 #if NCARP > 0
        if (ifp != ifp0)
                ifp0->if_obytes += m->m_pkthdr.len + ETHER_HDR_LEN;
-#endif /* NCARP > 0 */
+#endif
 
 #ifdef ALTQ
        KERNEL_LOCK(1, NULL);