fixed BPF generation of OSI over {CHDLC and ATM-LLC} frames

diff --git a/gencode.c b/gencode.c
index 08e89fed6e2bf06fe65e72152eb0b4038096d8fb..19aa2998c849585cdf64de1cebe53e86760e75bd 100644 (file)
--- a/gencode.c
+++ b/gencode.c
@@ -21,7 +21,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.180 2002-10-18 08:46:13 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.181 2002-12-04 21:40:13 hannes Exp $ (LBL)";
 #endif
 
 #ifdef HAVE_CONFIG_H
@@ -839,6 +839,10 @@ init_linktype(type)
                return;
 
        case DLT_ATM_RFC1483:
+               off_linktype = 0;
+               off_nl = 4;             /* FIXME SNAP */
+               return;
+
        case DLT_ATM_CLIP:      /* Linux ATM defines this */
                /*
                 * assume routed, non-ISO PDUs
@@ -964,9 +968,6 @@ gen_ether_linktype(proto)
        case LLCSAP_ISONS:
                /*
                 * OSI protocols always use 802.2 encapsulation.
-                * XXX - should we check both the DSAP and the
-                * SSAP, like this, or should we check just the
-                * DSAP?
                 */
                b0 = gen_cmp_gt(off_linktype, BPF_H, ETHERMTU);
                gen_not(b0);
@@ -975,12 +976,17 @@ gen_ether_linktype(proto)
                gen_and(b0, b1);
                return b1;
 
+       case LLCSAP_IP:
+               b0 = gen_cmp_gt(off_linktype, BPF_H, ETHERMTU);
+               gen_not(b0);
+               b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
+                            ((LLCSAP_IP << 8) | LLCSAP_IP));
+               gen_and(b0, b1);
+               return b1;
+
        case LLCSAP_NETBEUI:
                /*
                 * NetBEUI always uses 802.2 encapsulation.
-                * XXX - should we check both the DSAP and the
-                * SSAP, like this, or should we check just the
-                * DSAP?
                 */
                b0 = gen_cmp_gt(off_linktype, BPF_H, ETHERMTU);
                gen_not(b0);
@@ -1141,6 +1147,15 @@ gen_linktype(proto)
                return gen_ether_linktype(proto);
                break;
 
+        case DLT_C_HDLC:
+            switch (proto) {
+            case LLCSAP_ISONS:
+                proto = (proto << 8 | LLCSAP_ISONS);
+                /* fall through */
+            default:
+                return gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
+                break;
+            }
        case DLT_IEEE802_11:
        case DLT_PRISM_HEADER:
        case DLT_FDDI:
@@ -1188,12 +1203,16 @@ gen_linktype(proto)
        case DLT_LINUX_SLL:
                switch (proto) {
 
+               case LLCSAP_IP:
+                       b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
+                       b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
+                                    ((LLCSAP_IP << 8) | LLCSAP_IP));
+                       gen_and(b0, b1);
+                       return b1;
+
                case LLCSAP_ISONS:
                        /*
                         * OSI protocols always use 802.2 encapsulation.
-                        * XXX - should we check both the DSAP and the
-                        * LSAP, like this, or should we check just the
-                        * DSAP?
                         */
                        b0 = gen_cmp(off_linktype, BPF_H, LINUX_SLL_P_802_2);
                        b1 = gen_cmp(off_linktype + 2, BPF_H, (bpf_int32)
@@ -1372,7 +1391,7 @@ gen_linktype(proto)
                switch (proto) {
 
                case ETHERTYPE_IP:
-                       proto = PPP_IP;                 /* XXX was 0x21 */
+                       proto = PPP_IP;
                        break;
 
 #ifdef INET6
@@ -1679,6 +1698,10 @@ gen_llc(proto)
         */
        switch (proto) {
 
+        case LLCSAP_IP:
+               return gen_cmp(off_linktype, BPF_H, (long)
+                            ((LLCSAP_IP << 8) | LLCSAP_IP));
+                
        case LLCSAP_ISONS:
                return gen_cmp(off_linktype, BPF_H, (long)
                             ((LLCSAP_ISONS << 8) | LLCSAP_ISONS));
@@ -2950,8 +2973,19 @@ gen_port(port, ip_proto, dir)
 {
        struct block *b0, *b1, *tmp;
 
-       /* ether proto ip */
-       b0 =  gen_linktype(ETHERTYPE_IP);
+        switch (linktype) {
+        case DLT_IEEE802_11:
+        case DLT_PRISM_HEADER:
+        case DLT_FDDI:
+        case DLT_IEEE802:
+        case DLT_ATM_RFC1483:
+        case DLT_ATM_CLIP:
+                b0 = gen_linktype(LLCSAP_IP);
+                break;
+        default:
+                b0 = gen_linktype(ETHERTYPE_IP);
+                break;
+        }
 
        switch (ip_proto) {
        case IPPROTO_UDP:
@@ -3415,7 +3449,19 @@ gen_proto(v, proto, dir)
                /*FALLTHROUGH*/
 #endif
        case Q_IP:
-               b0 = gen_linktype(ETHERTYPE_IP);
+                switch (linktype) {
+                case DLT_IEEE802_11:
+                case DLT_PRISM_HEADER:
+                case DLT_FDDI:
+                case DLT_IEEE802:
+                case DLT_ATM_RFC1483:
+                case DLT_ATM_CLIP:
+                       b0 = gen_linktype(LLCSAP_IP);
+                        break;
+                default:
+                        b0 = gen_linktype(ETHERTYPE_IP);
+                        break;
+                }
 #ifndef CHASE_CHAIN
                b1 = gen_cmp(off_nl + 9, BPF_B, (bpf_int32)v);
 #else
@@ -3449,6 +3495,13 @@ gen_proto(v, proto, dir)
                        return gen_cmp(2, BPF_H, (0x03<<8) | v);
                        break;
 
+                case DLT_C_HDLC:
+                        /* Cisco uses an Ethertype lookalike - for OSI its 0xfefe */
+                        b0 = gen_linktype(LLCSAP_ISONS<<8 | LLCSAP_ISONS);
+                        /* OSI in C-HDLC is stuffed with a fudge byte */
+                       b1 = gen_cmp(off_nl_nosnap+1, BPF_B, (long)v);
+                       gen_and(b0, b1);
+                        return b1;
                default:
                        b0 = gen_linktype(LLCSAP_ISONS);
                        b1 = gen_cmp(off_nl_nosnap, BPF_B, (long)v);