[src/trunk]: src/sys/net eco_input():

[bjh21 <bjh21%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/26ea03723b40
branches:  trunk
changeset: 515083:26ea03723b40
user:      bjh21 <bjh21%NetBSD.org@localhost>
date:      Sun Sep 16 12:16:50 2001 +0000

description:
eco_input():
  Use m_copydata() to preserve the Econet header, so we don't depend on
  notionally-unused areas of an mbuf remaining untouched.
  Check that ARP-over-Econet requests are exactly eight bytes long.
  Use m_pullup() before trusting mtod().

Between them, these make reception of unicast ARP responses work properly.

diffstat:

 sys/net/if_ecosubr.c |  19 +++++++++++++------
 1 files changed, 13 insertions(+), 6 deletions(-)

diffs (54 lines):

diff -r 7816fd28d6bb -r 26ea03723b40 sys/net/if_ecosubr.c
--- a/sys/net/if_ecosubr.c      Sun Sep 16 12:16:20 2001 +0000
+++ b/sys/net/if_ecosubr.c      Sun Sep 16 12:16:50 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_ecosubr.c,v 1.5 2001/09/15 23:03:11 bjh21 Exp $     */
+/*     $NetBSD: if_ecosubr.c,v 1.6 2001/09/16 12:16:50 bjh21 Exp $     */
 
 /*-
  * Copyright (c) 2001 Ben Harris
@@ -66,7 +66,7 @@
 
 #include <sys/param.h>
 
-__KERNEL_RCSID(0, "$NetBSD: if_ecosubr.c,v 1.5 2001/09/15 23:03:11 bjh21 Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_ecosubr.c,v 1.6 2001/09/16 12:16:50 bjh21 Exp $");
 
 #include <sys/errno.h>
 #include <sys/kernel.h>
@@ -340,7 +340,7 @@
 eco_input(struct ifnet *ifp, struct mbuf *m)
 {
        struct ifqueue *inq;
-       struct eco_header *eh;
+       struct eco_header ehdr, *eh;
        int s;
 #ifdef INET
        struct arphdr *ah;
@@ -355,9 +355,10 @@
                return;
 #endif
 
-       eh = mtod(m, struct eco_header *);
-
-       /* Trim header of front (eh continues to be valid). */
+       /* Copy the mbuf header and trim it off. */
+       /* XXX use m_split? */
+       eh = &ehdr;
+       m_copydata(m, 0, ECO_HDR_LEN, (caddr_t)eh);
        m_adj(m, ECO_HDR_LEN);
 
        switch (eh->eco_port) {
@@ -378,6 +379,12 @@
                         * and we have to infer the rest and build a fake ARP
                         * packet to pass upwards.
                         */
+                       if (m->m_pkthdr.len != sizeof(struct eco_arp))
+                               goto drop;
+                       if (m->m_len < sizeof(struct eco_arp)) {
+                               m = m_pullup(m, sizeof(struct eco_arp));
+                               if (m == NULL) goto drop;
+                       }
                        ecah = mtod(m, struct eco_arp *);
                        /* This code derived from arprequest() */
                        MGETHDR(m1, M_DONTWAIT, MT_DATA);