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Patch from Monroe Williams <monroe@pobox.com>, submitted with NetBSD PR

#5228, to correctly check for Appletalk for EtherTalk phase II - they
use 802.3 with LLC SNAP packets, rather than D/I/X Ethernet packets.

His patch made "atalk" check for Appletalk ARP as well as other
Appletalk packets; I've instead added a separate "aarp" packet type,
leaving "atalk" checking only for ETHERTYPE_ATALK, so you can check for
ETHERTYPE_ATALK, ETHERTYPE_AARP, or both.
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1 parent 8c16ead commit 54b2ab13c29b96c9d587a0fb348ae8a1caccf08f @yuguy yuguy committed Oct 28, 2000
Showing with 117 additions and 5 deletions.
  1. +1 −0 CREDITS
  2. +108 −1 gencode.c
  3. +3 −1 gencode.h
  4. +3 −2 grammar.y
  5. +2 −1 scanner.l
View
1 CREDITS
@@ -19,6 +19,7 @@ Additional people who have contributed patches:
Jefferson Ogata <jogata@nodc.noaa.gov>
Juergen Schoenwaelder <schoenw@ibr.cs.tu-bs.de>
Love H�rnquist-�strand <lha@stacken.kth.se>
+ Monroe Williams <monroe@pobox.com>
Peter Jeremy <peter.jeremy@alcatel.com.au>
Rafal Maszkowski <rzm@icm.edu.pl>
Rick Jones <raj@cup.hp.com>
View
109 gencode.c
@@ -21,7 +21,7 @@
*/
#ifndef lint
static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.126 2000-10-28 00:01:26 guy Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/libpcap/gencode.c,v 1.127 2000-10-28 08:19:29 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@@ -124,12 +124,14 @@ static inline void syntax(void);
static void backpatch(struct block *, struct block *);
static void merge(struct block *, struct block *);
static struct block *gen_cmp(u_int, u_int, bpf_int32);
+static struct block *gen_cmp_gt(u_int, u_int, bpf_int32);
static struct block *gen_mcmp(u_int, u_int, bpf_int32, bpf_u_int32);
static struct block *gen_bcmp(u_int, u_int, const u_char *);
static struct block *gen_uncond(int);
static inline struct block *gen_true(void);
static inline struct block *gen_false(void);
static struct block *gen_linktype(int);
+static struct block *gen_snap(bpf_u_int32, bpf_u_int32, u_int);
static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int);
#ifdef INET6
static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int);
@@ -487,6 +489,24 @@ gen_cmp(offset, size, v)
}
static struct block *
+gen_cmp_gt(offset, size, v)
+ u_int offset, size;
+ bpf_int32 v;
+{
+ struct slist *s;
+ struct block *b;
+
+ s = new_stmt(BPF_LD|BPF_ABS|size);
+ s->s.k = offset;
+
+ b = new_block(JMP(BPF_JGT));
+ b->stmts = s;
+ b->s.k = v;
+
+ return b;
+}
+
+static struct block *
gen_mcmp(offset, size, v, mask)
u_int offset, size;
bpf_int32 v;
@@ -703,6 +723,57 @@ gen_linktype(proto)
switch (linktype) {
+ case DLT_EN10MB:
+ /*
+ * XXX - handle other LLC-encapsulated protocols here
+ * (IPX, OSI)?
+ */
+ switch (proto) {
+
+ case ETHERTYPE_ATALK:
+ case ETHERTYPE_AARP:
+ /*
+ * EtherTalk (AppleTalk protocols on Ethernet link
+ * layer) may use 802.2 encapsulation.
+ */
+
+ /*
+ * Check for 802.2 encapsulation (EtherTalk phase 2?);
+ * we check for an Ethernet type field less than
+ * 1500, which means it's an 802.3 length field.
+ */
+ b0 = gen_cmp_gt(off_linktype, BPF_H, 1500);
+ gen_not(b0);
+
+ /*
+ * 802.2-encapsulated ETHERTYPE_ATALK packets are
+ * SNAP packets with an organization code of
+ * 0x080007 (Apple, for Appletalk) and a protocol
+ * type of ETHERTYPE_ATALK (Appletalk).
+ *
+ * 802.2-encapsulated ETHERTYPE_AARP packets are
+ * SNAP packets with an organization code of
+ * 0x000000 (encapsulated Ethernet) and a protocol
+ * type of ETHERTYPE_AARP (Appletalk ARP).
+ */
+ if (proto == ETHERTYPE_ATALK)
+ b1 = gen_snap(0x080007, ETHERTYPE_ATALK, 14);
+ else /* proto == ETHERTYPE_AARP */
+ b1 = gen_snap(0x000000, ETHERTYPE_AARP, 14);
+ gen_and(b0, b1);
+
+ /*
+ * Check for Ethernet encapsulation (Ethertalk
+ * phase 1?); we just check for the Ethernet
+ * protocol type.
+ */
+ b0 = gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
+
+ gen_or(b0, b1);
+ return b1;
+ }
+ break;
+
case DLT_SLIP:
return gen_false();
@@ -762,6 +833,32 @@ gen_linktype(proto)
return gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
}
+/*
+ * Check for an LLC SNAP packet with a given organization code and
+ * protocol type; we check the entire contents of the 802.2 LLC and
+ * snap headers, checking for a DSAP of 0xAA, an SSAP of 0xAA, and
+ * a control field of 0x03 in the LLC header, and for the specified
+ * organization code and protocol type in the SNAP header.
+ */
+static struct block *
+gen_snap(orgcode, ptype, offset)
+ bpf_u_int32 orgcode;
+ bpf_u_int32 ptype;
+ u_int offset;
+{
+ u_char snapblock[8];
+
+ snapblock[0] = 0xAA; /* DSAP = SNAP */
+ snapblock[1] = 0xAA; /* SSAP = SNAP */
+ snapblock[2] = 0x03; /* control = UI */
+ snapblock[3] = (orgcode >> 16); /* upper 8 bits of organization code */
+ snapblock[4] = (orgcode >> 8); /* middle 8 bits of organization code */
+ snapblock[5] = (orgcode >> 0); /* lower 8 bits of organization code */
+ snapblock[6] = (ptype >> 8); /* upper 8 bits of protocol type */
+ snapblock[7] = (ptype >> 0); /* lower 8 bits of protocol type */
+ return gen_bcmp(offset, 8, snapblock);
+}
+
static struct block *
gen_hostop(addr, mask, dir, proto, src_off, dst_off)
bpf_u_int32 addr;
@@ -1107,6 +1204,9 @@ gen_host(addr, mask, proto, dir)
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
+ case Q_AARP:
+ bpf_error("AARP host filtering not implemented");
+
case Q_DECNET:
return gen_dnhostop(addr, dir, off_nl);
@@ -1185,6 +1285,9 @@ gen_host6(addr, mask, proto, dir)
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
+ case Q_AARP:
+ bpf_error("AARP host filtering not implemented");
+
case Q_DECNET:
bpf_error("'decnet' modifier applied to ip6 host");
@@ -1340,6 +1443,10 @@ gen_proto_abbrev(proto)
b1 = gen_linktype(ETHERTYPE_ATALK);
break;
+ case Q_AARP:
+ b1 = gen_linktype(ETHERTYPE_AARP);
+ break;
+
case Q_DECNET:
b1 = gen_linktype(ETHERTYPE_DN);
break;
View
4 gencode.h
@@ -18,7 +18,7 @@
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
- * @(#) $Header: /tcpdump/master/libpcap/gencode.h,v 1.43 2000-10-28 00:01:27 guy Exp $ (LBL)
+ * @(#) $Header: /tcpdump/master/libpcap/gencode.h,v 1.44 2000-10-28 08:19:29 guy Exp $ (LBL)
*/
/* Address qualifiers. */
@@ -58,6 +58,8 @@
#define Q_PIM 20
+#define Q_AARP 21
+
/* Directional qualifiers. */
#define Q_SRC 1
View
5 grammar.y
@@ -22,7 +22,7 @@
*/
#ifndef lint
static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/libpcap/grammar.y,v 1.61 2000-10-22 04:15:56 guy Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/libpcap/grammar.y,v 1.62 2000-10-28 08:19:30 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@@ -107,7 +107,7 @@ pcap_parse()
%token DST SRC HOST GATEWAY
%token NET MASK PORT LESS GREATER PROTO PROTOCHAIN BYTE
%token ARP RARP IP TCP UDP ICMP IGMP IGRP PIM
-%token ATALK DECNET LAT SCA MOPRC MOPDL
+%token ATALK AARP DECNET LAT SCA MOPRC MOPDL
%token TK_BROADCAST TK_MULTICAST
%token NUM INBOUND OUTBOUND
%token LINK
@@ -248,6 +248,7 @@ pname: LINK { $$ = Q_LINK; }
| IGRP { $$ = Q_IGRP; }
| PIM { $$ = Q_PIM; }
| ATALK { $$ = Q_ATALK; }
+ | AARP { $$ = Q_AARP; }
| DECNET { $$ = Q_DECNET; }
| LAT { $$ = Q_LAT; }
| SCA { $$ = Q_SCA; }
View
3 scanner.l
@@ -22,7 +22,7 @@
#ifndef lint
static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/libpcap/scanner.l,v 1.67 2000-10-22 04:15:56 guy Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/libpcap/scanner.l,v 1.68 2000-10-28 08:19:30 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@@ -183,6 +183,7 @@ ah return AH;
esp return ESP;
atalk return ATALK;
+aarp return AARP;
decnet return DECNET;
lat return LAT;
sca return SCA;

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