]> The Tcpdump Group git mirrors - tcpdump/blobdiff - print-llc.c
The third argument to linkaddr_string is one of the LINKADDR_ enums.
[tcpdump] / print-llc.c
index f1b8eb423c03c8e397b535e344228c2916e512fe..750a8ccdae5499a4f2f5127922ae9b813dad90f4 100644 (file)
  *     with an awful lot of hacking by Jeffrey Mogul, DECWRL
  */
 
-#ifndef lint
-static const char rcsid[] _U_ =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-llc.c,v 1.60 2005-04-06 20:09:08 hannes Exp $";
-#endif
+/* \summary: IEEE 802.2 LLC printer */
 
 #ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
 #endif
 
-#include <tcpdump-stdinc.h>
-
-#include <stdio.h>
-#include <string.h>
+#include "netdissect-stdinc.h"
 
-#include "interface.h"
+#include "netdissect.h"
 #include "addrtoname.h"
-#include "extract.h"                   /* must come after interface.h */
+#include "extract.h"
 
 #include "llc.h"
 #include "ethertype.h"
 #include "oui.h"
 
-static struct tok llc_values[] = {
+static const struct tok llc_values[] = {
         { LLCSAP_NULL,     "Null" },
         { LLCSAP_GLOBAL,   "Global" },
         { LLCSAP_8021B_I,  "802.1B I" },
         { LLCSAP_8021B_G,  "802.1B G" },
         { LLCSAP_IP,       "IP" },
+        { LLCSAP_SNA,      "SNA" },
         { LLCSAP_PROWAYNM, "ProWay NM" },
         { LLCSAP_8021D,    "STP" },
         { LLCSAP_RS511,    "RS511" },
@@ -59,9 +54,10 @@ static struct tok llc_values[] = {
         { LLCSAP_IPX,      "IPX" },
         { LLCSAP_NETBEUI,  "NetBeui" },
         { LLCSAP_ISONS,    "OSI" },
+        { 0,               NULL },
 };
 
-static struct tok cmd2str[] = {
+static const struct tok llc_cmd_values[] = {
        { LLC_UI,       "ui" },
        { LLC_TEST,     "test" },
        { LLC_XID,      "xid" },
@@ -73,44 +69,153 @@ static struct tok cmd2str[] = {
        { 0,            NULL }
 };
 
+static const struct tok llc_flag_values[] = {
+        { 0, "Command" },
+        { LLC_GSAP, "Response" },
+        { LLC_U_POLL, "Poll" },
+        { LLC_GSAP|LLC_U_POLL, "Final" },
+        { LLC_IS_POLL, "Poll" },
+        { LLC_GSAP|LLC_IS_POLL, "Final" },
+       { 0, NULL }
+};
+
+
+static const struct tok llc_ig_flag_values[] = {
+        { 0, "Individual" },
+        { LLC_IG, "Group" },
+       { 0, NULL }
+};
+
+
+static const struct tok llc_supervisory_values[] = {
+        { 0, "Receiver Ready" },
+        { 1, "Receiver not Ready" },
+        { 2, "Reject" },
+       { 0,             NULL }
+};
+
+
+static const struct tok cisco_values[] = {
+       { PID_CISCO_CDP, "CDP" },
+       { PID_CISCO_VTP, "VTP" },
+       { PID_CISCO_DTP, "DTP" },
+       { PID_CISCO_UDLD, "UDLD" },
+       { PID_CISCO_PVST, "PVST" },
+       { PID_CISCO_VLANBRIDGE, "VLAN Bridge" },
+       { 0,             NULL }
+};
+
+static const struct tok bridged_values[] = {
+       { PID_RFC2684_ETH_FCS,     "Ethernet + FCS" },
+       { PID_RFC2684_ETH_NOFCS,   "Ethernet w/o FCS" },
+       { PID_RFC2684_802_4_FCS,   "802.4 + FCS" },
+       { PID_RFC2684_802_4_NOFCS, "802.4 w/o FCS" },
+       { PID_RFC2684_802_5_FCS,   "Token Ring + FCS" },
+       { PID_RFC2684_802_5_NOFCS, "Token Ring w/o FCS" },
+       { PID_RFC2684_FDDI_FCS,    "FDDI + FCS" },
+       { PID_RFC2684_FDDI_NOFCS,  "FDDI w/o FCS" },
+       { PID_RFC2684_802_6_FCS,   "802.6 + FCS" },
+       { PID_RFC2684_802_6_NOFCS, "802.6 w/o FCS" },
+       { PID_RFC2684_BPDU,        "BPDU" },
+       { 0,                       NULL },
+};
+
+static const struct tok null_values[] = {
+       { 0,             NULL }
+};
+
+struct oui_tok {
+       uint32_t        oui;
+       const struct tok *tok;
+};
+
+static const struct oui_tok oui_to_tok[] = {
+       { OUI_ENCAP_ETHER, ethertype_values },
+       { OUI_CISCO_90, ethertype_values },     /* uses some Ethertype values */
+       { OUI_APPLETALK, ethertype_values },    /* uses some Ethertype values */
+       { OUI_CISCO, cisco_values },
+       { OUI_RFC2684, bridged_values },        /* bridged, RFC 2427 FR or RFC 2864 ATM */
+       { 0, NULL }
+};
+
 /*
- * Returns non-zero IFF it succeeds in printing the header
+ * If we printed information about the payload, returns the length of the LLC
+ * header, plus the length of any SNAP header following it.
+ *
+ * Otherwise (for example, if the packet has unknown SAPs or has a SNAP
+ * header with an unknown OUI/PID combination), returns the *negative*
+ * of that value.
  */
 int
-llc_print(const u_char *p, u_int length, u_int caplen,
-         const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
+llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
+         const struct lladdr_info *src, const struct lladdr_info *dst)
 {
-       struct llc llc;
-       register u_short et;
-       u_int16_t control;
-       register int ret;
+       uint8_t dsap_field, dsap, ssap_field, ssap;
+       uint16_t control;
+       int hdrlen;
+       int is_u;
 
+       ndo->ndo_protocol = "llc";
        if (caplen < 3) {
-               (void)printf("[|llc]");
-               default_print((u_char *)p, caplen);
-               return(0);
+               nd_print_trunc(ndo);
+               ND_DEFAULTPRINT((const u_char *)p, caplen);
+               return (caplen);
+       }
+       if (length < 3) {
+               nd_print_trunc(ndo);
+               ND_DEFAULTPRINT((const u_char *)p, caplen);
+               return (length);
        }
 
-       /* Watch out for possible alignment problems */
-       memcpy((char *)&llc, (char *)p, min(caplen, sizeof(llc)));
+       dsap_field = GET_U_1(p);
+       ssap_field = GET_U_1(p + 1);
+
+       /*
+        * OK, what type of LLC frame is this?  The length
+        * of the control field depends on that - I frames
+        * have a two-byte control field, and U frames have
+        * a one-byte control field.
+        */
+       control = GET_U_1(p + 2);
+       if ((control & LLC_U_FMT) == LLC_U_FMT) {
+               /*
+                * U frame.
+                */
+               is_u = 1;
+               hdrlen = 3;     /* DSAP, SSAP, 1-byte control field */
+       } else {
+               /*
+                * The control field in I and S frames is
+                * 2 bytes...
+                */
+               if (caplen < 4) {
+                       nd_print_trunc(ndo);
+                       ND_DEFAULTPRINT((const u_char *)p, caplen);
+                       return (caplen);
+               }
+               if (length < 4) {
+                       nd_print_trunc(ndo);
+                       ND_DEFAULTPRINT((const u_char *)p, caplen);
+                       return (length);
+               }
 
-       if (eflag)
-         printf("LLC, dsap %s (0x%02x), ssap %s (0x%02x), cmd 0x%02x: ",
-                 tok2str(llc_values,"Unknown",llc.dsap),
-                llc.dsap,
-                 tok2str(llc_values,"Unknown",llc.ssap),
-                llc.ssap,
-                llc.llcu);
+               /*
+                * ...and is little-endian.
+                */
+               control = GET_LE_U_2(p + 2);
+               is_u = 0;
+               hdrlen = 4;     /* DSAP, SSAP, 2-byte control field */
+       }
 
-       if (llc.ssap == LLCSAP_GLOBAL && llc.dsap == LLCSAP_GLOBAL) {
+       if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
                /*
                 * This is an Ethernet_802.3 IPX frame; it has an
                 * 802.3 header (i.e., an Ethernet header where the
-                * type/length field is <= ETHERMTU, i.e. it's a length
-                * field, not a type field), but has no 802.2 header -
-                * the IPX packet starts right after the Ethernet header,
-                * with a signature of two bytes of 0xFF (which is
-                * LLCSAP_GLOBAL).
+                * type/length field is <= MAX_ETHERNET_LENGTH_VAL,
+                * i.e. it's a length field, not a type field), but
+                * has no 802.2 header - the IPX packet starts right
+                * after the Ethernet header, with a signature of two
+                * bytes of 0xFF (which is LLCSAP_GLOBAL).
                 *
                 * (It might also have been an Ethernet_802.3 IPX at
                 * one time, but got bridged onto another network,
@@ -118,43 +223,92 @@ llc_print(const u_char *p, u_int length, u_int caplen,
                 * least one capture file.)
                 */
 
-            if (eflag)
-               printf("IPX-802.3: ");
+            if (ndo->ndo_eflag)
+               ND_PRINT("IPX 802.3: ");
 
-            ipx_print(p, length);
-            return (1);
+            ipx_print(ndo, p, length);
+            return (0);                /* no LLC header */
        }
 
-       if (llc.ssap == LLCSAP_8021D && llc.dsap == LLCSAP_8021D) {
-               stp_print(p, length);
-               return (1);
+       dsap = dsap_field & ~LLC_IG;
+       ssap = ssap_field & ~LLC_GSAP;
+
+       if (ndo->ndo_eflag) {
+                ND_PRINT("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
+                       tok2str(llc_values, "Unknown", dsap),
+                       dsap,
+                       tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
+                       tok2str(llc_values, "Unknown", ssap),
+                       ssap,
+                       tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP));
+
+               if (is_u) {
+                       ND_PRINT(", ctrl 0x%02x: ", control);
+               } else {
+                       ND_PRINT(", ctrl 0x%04x: ", control);
+               }
        }
 
-       if (llc.ssap == LLCSAP_IP && llc.dsap == LLCSAP_IP) {
-               ip_print(p+4, length-4);
-               return (1);
+       /*
+        * Skip LLC header.
+        */
+       p += hdrlen;
+       length -= hdrlen;
+       caplen -= hdrlen;
+
+       if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
+           && control == LLC_UI) {
+               /*
+                * XXX - what *is* the right bridge pad value here?
+                * Does anybody ever bridge one form of LAN traffic
+                * over a networking type that uses 802.2 LLC?
+                */
+               if (!snap_print(ndo, p, length, caplen, src, dst, 2)) {
+                       /*
+                        * Unknown packet type; tell our caller, by
+                        * returning a negative value, so they
+                        * can print the raw packet.
+                        */
+                       return (-(hdrlen + 5)); /* include LLC and SNAP header */
+               } else
+                       return (hdrlen + 5);    /* include LLC and SNAP header */
        }
 
-       if (llc.ssap == LLCSAP_IPX && llc.dsap == LLCSAP_IPX &&
-           llc.llcui == LLC_UI) {
+       if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
+           control == LLC_UI) {
+               stp_print(ndo, p, length);
+               return (hdrlen);
+       }
+
+       if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
+           control == LLC_UI) {
+               /*
+                * This is an RFC 948-style IP packet, with
+                * an 802.3 header and an 802.2 LLC header
+                * with the source and destination SAPs being
+                * the IP SAP.
+                */
+               ip_print(ndo, p, length);
+               return (hdrlen);
+       }
+
+       if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
+           control == LLC_UI) {
                /*
                 * This is an Ethernet_802.2 IPX frame, with an 802.3
                 * header and an 802.2 LLC header with the source and
                 * destination SAPs being the IPX SAP.
-                *
-                * Skip DSAP, LSAP, and control field.
                 */
-               printf("(NOV-802.2) ");
-               p += 3;
-               length -= 3;
-               caplen -= 3;
-               ipx_print(p, length);
-               return (1);
+                if (ndo->ndo_eflag)
+                        ND_PRINT("IPX 802.2: ");
+
+               ipx_print(ndo, p, length);
+               return (hdrlen);
        }
 
-#ifdef TCPDUMP_DO_SMB
-       if (llc.ssap == LLCSAP_NETBEUI && llc.dsap == LLCSAP_NETBEUI
-           && (!(llc.llcu & LLC_S_FMT) || llc.llcu == LLC_U_FMT)) {
+#ifdef ENABLE_SMB
+       if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
+           && (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
                /*
                 * we don't actually have a full netbeui parser yet, but the
                 * smb parser can handle many smb-in-netbeui packets, which
@@ -165,170 +319,138 @@ llc_print(const u_char *p, u_int length, u_int caplen,
                 * LLC_S_FMT, set in the first byte of the control field)
                 * and UI frames (whose control field is just 3, LLC_U_FMT).
                 */
-
-               /*
-                * Skip the DSAP and LSAP.
-                */
-               p += 2;
-               length -= 2;
-               caplen -= 2;
-
-               /*
-                * OK, what type of LLC frame is this?  The length
-                * of the control field depends on that - I frames
-                * have a two-byte control field, and U frames have
-                * a one-byte control field.
-                */
-               if (llc.llcu == LLC_U_FMT) {
-                       control = llc.llcu;
-                       p += 1;
-                       length -= 1;
-                       caplen -= 1;
-               } else {
-                       /*
-                        * The control field in I and S frames is
-                        * little-endian.
-                        */
-                       control = EXTRACT_LE_16BITS(&llc.llcu);
-                       p += 2;
-                       length -= 2;
-                       caplen -= 2;
-               }
-               netbeui_print(control, p, length);
-               return (1);
+               netbeui_print(ndo, control, p, length);
+               return (hdrlen);
        }
 #endif
-       if (llc.ssap == LLCSAP_ISONS && llc.dsap == LLCSAP_ISONS
-           && llc.llcui == LLC_UI) {
-               isoclns_print(p + 3, length - 3, caplen - 3);
-               return (1);
+       if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
+           && control == LLC_UI) {
+               isoclns_print(ndo, p, length);
+               return (hdrlen);
        }
 
-       if (llc.ssap == LLCSAP_SNAP && llc.dsap == LLCSAP_SNAP
-           && llc.llcui == LLC_UI) {
-               u_int32_t orgcode;
-
-               if (caplen < sizeof(llc)) {
-                       (void)printf("[|llc-snap]");
-                       default_print((u_char *)p, caplen);
-                       return (0);
+       if (!ndo->ndo_eflag) {
+               if (ssap == dsap) {
+                       if (src == NULL || dst == NULL)
+                               ND_PRINT("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
+                       else
+                               ND_PRINT("%s > %s %s ",
+                                               (src->addr_string)(ndo, src->addr),
+                                               (dst->addr_string)(ndo, dst->addr),
+                                               tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
+               } else {
+                       if (src == NULL || dst == NULL)
+                               ND_PRINT("%s > %s ",
+                                        tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
+                                       tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
+                       else
+                               ND_PRINT("%s %s > %s %s ",
+                                       (src->addr_string)(ndo, src->addr),
+                                        tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
+                                       (dst->addr_string)(ndo, dst->addr),
+                                       tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
                }
-
-               caplen -= sizeof(llc);
-               length -= sizeof(llc);
-               p += sizeof(llc);
-
-               orgcode = EXTRACT_24BITS(&llc.llc_orgcode[0]);
-               et = EXTRACT_16BITS(&llc.llc_ethertype[0]);
-
-                if (eflag)
-                    (void)printf("oui %s (0x%06x), ethertype %s (0x%04x): ",
-                                 tok2str(oui_values,"Unknown",orgcode),
-                                 orgcode,
-                                 tok2str(ethertype_values,"Unknown", et),
-                                 et);
-
-               /*
-                * XXX - what *is* the right bridge pad value here?
-                * Does anybody ever bridge one form of LAN traffic
-                * over a networking type that uses 802.2 LLC?
-                */
-               ret = snap_print(p, length, caplen, extracted_ethertype,
-                   orgcode, et, 2);
-               if (ret)
-                       return (ret);
        }
 
-       if ((llc.ssap & ~LLC_GSAP) == llc.dsap) {
-               if (eflag || esrc == NULL || edst == NULL)
-                       (void)printf("%s ", llcsap_string(llc.dsap));
-               else
-                       (void)printf("%s > %s %s ",
-                                       etheraddr_string(esrc),
-                                       etheraddr_string(edst),
-                                       llcsap_string(llc.dsap));
-       } else {
-               if (eflag || esrc == NULL || edst == NULL)
-                       (void)printf("%s > %s ",
-                               llcsap_string(llc.ssap & ~LLC_GSAP),
-                               llcsap_string(llc.dsap));
-               else
-                       (void)printf("%s %s > %s %s ",
-                               etheraddr_string(esrc),
-                               llcsap_string(llc.ssap & ~LLC_GSAP),
-                               etheraddr_string(edst),
-                               llcsap_string(llc.dsap));
-       }
-
-       if ((llc.llcu & LLC_U_FMT) == LLC_U_FMT) {
-               u_int16_t cmd;
-               const char *m;
-               char f;
-
-               cmd = LLC_U_CMD(llc.llcu);
-               m = tok2str(cmd2str, "%02x", cmd);
-               switch ((llc.ssap & LLC_GSAP) | (llc.llcu & LLC_U_POLL)) {
-                       case 0:                 f = 'C'; break;
-                       case LLC_GSAP:          f = 'R'; break;
-                       case LLC_U_POLL:        f = 'P'; break;
-                       case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
-                       default:                f = '?'; break;
-               }
-
-               printf("%s/%c", m, f);
-
-               p += 3;
-               length -= 3;
-               caplen -= 3;
-
-               if ((llc.llcu & ~LLC_U_POLL) == LLC_XID) {
-                       if (*p == LLC_XID_FI) {
-                               printf(": %02x %02x", p[1], p[2]);
-                               p += 3;
-                               length -= 3;
-                               caplen -= 3;
+       if (is_u) {
+               ND_PRINT("Unnumbered, %s, Flags [%s], length %u",
+                       tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
+                       tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
+                       length + hdrlen);
+
+               if ((control & ~LLC_U_POLL) == LLC_XID) {
+                       if (length == 0) {
+                               /*
+                                * XID with no payload.
+                                * This could, for example, be an SNA
+                                * "short form" XID.
+                                 */
+                               return (hdrlen);
+                       }
+                       if (caplen < 1) {
+                               nd_print_trunc(ndo);
+                               if (caplen > 0)
+                                       ND_DEFAULTPRINT((const u_char *)p, caplen);
+                               return (hdrlen);
+                       }
+                       if (GET_U_1(p) == LLC_XID_FI) {
+                               if (caplen < 3 || length < 3) {
+                                       nd_print_trunc(ndo);
+                                       if (caplen > 0)
+                                               ND_DEFAULTPRINT((const u_char *)p, caplen);
+                               } else
+                                       ND_PRINT(": %02x %02x",
+                                                 GET_U_1(p + 1),
+                                                 GET_U_1(p + 2));
+                               return (hdrlen);
                        }
                }
        } else {
-               char f;
-
-               /*
-                * The control field in I and S frames is little-endian.
-                */
-               control = EXTRACT_LE_16BITS(&llc.llcu);
-               switch ((llc.ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
-                       case 0:                 f = 'C'; break;
-                       case LLC_GSAP:          f = 'R'; break;
-                       case LLC_IS_POLL:       f = 'P'; break;
-                       case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
-                       default:                f = '?'; break;
-               }
-
                if ((control & LLC_S_FMT) == LLC_S_FMT) {
-                       static const char *llc_s[] = { "rr", "rej", "rnr", "03" };
-                       (void)printf("%s (r=%d,%c)",
-                               llc_s[LLC_S_CMD(control)],
+                       ND_PRINT("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
+                               tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
                                LLC_IS_NR(control),
-                               f);
+                               tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
+                                length + hdrlen);
+                       return (hdrlen);        /* no payload to print */
                } else {
-                       (void)printf("I (s=%d,r=%d,%c)",
+                       ND_PRINT("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
                                LLC_I_NS(control),
                                LLC_IS_NR(control),
-                               f);
+                               tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
+                                length + hdrlen);
                }
-               p += 4;
-               length -= 4;
-               caplen -= 4;
        }
-       return(1);
+       return (-hdrlen);
+}
+
+static const struct tok *
+oui_to_struct_tok(uint32_t orgcode)
+{
+       const struct tok *tok = null_values;
+       const struct oui_tok *otp;
+
+       for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
+               if (otp->oui == orgcode) {
+                       tok = otp->tok;
+                       break;
+               }
+       }
+       return (tok);
 }
 
 int
-snap_print(const u_char *p, u_int length, u_int caplen,
-    u_short *extracted_ethertype, u_int32_t orgcode, u_short et,
-    u_int bridge_pad)
+snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
+       const struct lladdr_info *src, const struct lladdr_info *dst,
+       u_int bridge_pad)
 {
-       register int ret;
+       uint32_t orgcode;
+       u_short et;
+       int ret;
+
+       ndo->ndo_protocol = "snap";
+       ND_TCHECK_5(p);
+       if (caplen < 5 || length < 5)
+               goto trunc;
+       orgcode = GET_BE_U_3(p);
+       et = GET_BE_U_2(p + 3);
+
+       if (ndo->ndo_eflag) {
+               /*
+                * Somebody's already printed the MAC addresses, if there
+                * are any, so just print the SNAP header, not the MAC
+                * addresses.
+                */
+               ND_PRINT("oui %s (0x%06x), %s %s (0x%04x), length %u: ",
+                    tok2str(oui_values, "Unknown", orgcode),
+                    orgcode,
+                    (orgcode == 0x000000 ? "ethertype" : "pid"),
+                    tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
+                    et, length - 5);
+       }
+       p += 5;
+       length -= 5;
+       caplen -= 5;
 
        switch (orgcode) {
        case OUI_ENCAP_ETHER:
@@ -339,8 +461,7 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                 * Cisco hardware; the protocol ID is
                 * an Ethernet protocol type.
                 */
-               ret = ether_encap_print(et, p, length, caplen,
-                   extracted_ethertype);
+               ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
                if (ret)
                        return (ret);
                break;
@@ -355,18 +476,33 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                         * but used 0x000000 and an Ethernet
                         * packet type for AARP packets.
                         */
-                       ret = ether_encap_print(et, p, length, caplen,
-                           extracted_ethertype);
+                       ret = ethertype_print(ndo, et, p, length, caplen, src, dst);
                        if (ret)
                                return (ret);
                }
                break;
 
        case OUI_CISCO:
-               if (et == PID_CISCO_CDP) {
-                       cdp_print(p, length, caplen);
-                       return (1);
-               }
+                switch (et) {
+                case PID_CISCO_CDP:
+                        cdp_print(ndo, p, length, caplen);
+                        return (1);
+                case PID_CISCO_DTP:
+                        dtp_print(ndo, p, length);
+                        return (1);
+                case PID_CISCO_UDLD:
+                        udld_print(ndo, p, length);
+                        return (1);
+                case PID_CISCO_VTP:
+                        vtp_print(ndo, p, length);
+                        return (1);
+                case PID_CISCO_PVST:
+                case PID_CISCO_VLANBRIDGE:
+                        stp_print(ndo, p, length);
+                        return (1);
+                default:
+                        break;
+                }
                break;
 
        case OUI_RFC2684:
@@ -381,6 +517,7 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                        /*
                         * Skip the padding.
                         */
+                       ND_TCHECK_LEN(p, bridge_pad);
                        caplen -= bridge_pad;
                        length -= bridge_pad;
                        p += bridge_pad;
@@ -388,7 +525,7 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                        /*
                         * What remains is an Ethernet packet.
                         */
-                       ether_print(p, length, caplen);
+                       ether_print(ndo, p, length, caplen, NULL, NULL);
                        return (1);
 
                case PID_RFC2684_802_5_FCS:
@@ -401,6 +538,7 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                         * Skip the padding, but not the Access
                         * Control field.
                         */
+                       ND_TCHECK_LEN(p, bridge_pad);
                        caplen -= bridge_pad;
                        length -= bridge_pad;
                        p += bridge_pad;
@@ -409,7 +547,7 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                         * What remains is an 802.5 Token Ring
                         * packet.
                         */
-                       token_print(p, length, caplen);
+                       token_print(ndo, p, length, caplen);
                        return (1);
 
                case PID_RFC2684_FDDI_FCS:
@@ -421,6 +559,7 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                        /*
                         * Skip the padding.
                         */
+                       ND_TCHECK_LEN(p, bridge_pad + 1);
                        caplen -= bridge_pad + 1;
                        length -= bridge_pad + 1;
                        p += bridge_pad + 1;
@@ -428,13 +567,44 @@ snap_print(const u_char *p, u_int length, u_int caplen,
                        /*
                         * What remains is an FDDI packet.
                         */
-                       fddi_print(p, length, caplen);
+                       fddi_print(ndo, p, length, caplen);
                        return (1);
 
                case PID_RFC2684_BPDU:
-                       stp_print(p, length);
+                       stp_print(ndo, p, length);
                        return (1);
                }
        }
+       if (!ndo->ndo_eflag) {
+               /*
+                * Nobody printed the link-layer addresses, so print them, if
+                * we have any.
+                */
+               if (src != NULL && dst != NULL) {
+                       ND_PRINT("%s > %s ",
+                               (src->addr_string)(ndo, src->addr),
+                               (dst->addr_string)(ndo, dst->addr));
+               }
+               /*
+                * Print the SNAP header, but if the OUI is 000000, don't
+                * bother printing it, and report the PID as being an
+                * ethertype.
+                */
+               if (orgcode == 0x000000) {
+                       ND_PRINT("SNAP, ethertype %s (0x%04x), length %u: ",
+                            tok2str(ethertype_values, "Unknown", et),
+                            et, length);
+               } else {
+                       ND_PRINT("SNAP, oui %s (0x%06x), pid %s (0x%04x), length %u: ",
+                            tok2str(oui_values, "Unknown", orgcode),
+                            orgcode,
+                            tok2str(oui_to_struct_tok(orgcode), "Unknown", et),
+                            et, length);
+               }
+       }
        return (0);
+
+trunc:
+       nd_print_trunc(ndo);
+       return (1);
 }