Include files from the "epan" directory and subdirectories thereof with
[obnox/wireshark/wip.git] / packet-tr.c
index ee1b49a6972dae75296d939a39c2709b663bd4a4..465d6535859f59ddb979286fe8c790b749c9401f 100644 (file)
@@ -1,13 +1,12 @@
 /* packet-tr.c
  * Routines for Token-Ring packet disassembly
- * Gilbert Ramirez <gram@verdict.uthscsa.edu>
+ * Gilbert Ramirez <gram@alumni.rice.edu>
  *
- * $Id: packet-tr.c,v 1.13 1999/06/14 20:30:06 gram Exp $
+ * $Id: packet-tr.c,v 1.69 2002/01/21 07:36:44 guy Exp $
  *
  * Ethereal - Network traffic analyzer
- * By Gerald Combs <gerald@unicom.net>
+ * By Gerald Combs <gerald@ethereal.com>
  * Copyright 1998 Gerald Combs
- *
  * 
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
 # include <sys/types.h>
 #endif
 
+#include <string.h>
 #include <stdio.h>
 #include <glib.h>
-#include "packet.h"
-#include "etypes.h"
+#include <epan/packet.h>
+#include "packet-tr.h"
+#include "packet-llc.h"
+       
+static int proto_tr = -1;
+static int hf_tr_dst = -1;
+static int hf_tr_src = -1;
+static int hf_tr_addr = -1;
+static int hf_tr_sr = -1;
+static int hf_tr_ac = -1;
+static int hf_tr_priority = -1;
+static int hf_tr_frame = -1;
+static int hf_tr_monitor_cnt = -1;
+static int hf_tr_priority_reservation = -1;
+static int hf_tr_fc = -1;
+static int hf_tr_fc_type = -1;
+static int hf_tr_fc_pcf = -1;
+static int hf_tr_rif_bytes = -1;
+static int hf_tr_broadcast = -1;
+static int hf_tr_max_frame_size = -1;
+static int hf_tr_direction = -1;
+static int hf_tr_rif = -1;
+static int hf_tr_rif_ring = -1;
+static int hf_tr_rif_bridge = -1;
+
+static gint ett_token_ring = -1;
+static gint ett_token_ring_ac = -1;
+static gint ett_token_ring_fc = -1;
+
+#define TR_MIN_HEADER_LEN 14
+#define TR_MAX_HEADER_LEN 32
+
+static const true_false_string ac_truth = { "Frame", "Token" };
+
+static const value_string pcf_vals[] = {
+       { 0,    "Normal buffer" },
+       { 1,    "Express buffer" },
+       { 2,    "Purge" },
+       { 3,    "Claim Token" },
+       { 4,    "Beacon" },
+       { 5,    "Active Monitor Present" },
+       { 6,    "Standby Monitor Present" },
+       { 0,    NULL },
+};
+
+static const value_string frame_vals[] = {
+       { 0,    "MAC" },
+       { 1,    "LLC" },
+       { 2,    "Reserved" },
+       { 0,    NULL },
+};
+
+static const value_string broadcast_vals[] = {
+       { 0 << 5,       "Non-broadcast" },
+       { 1 << 5,       "Non-broadcast" },
+       { 2 << 5,       "Non-broadcast" },
+       { 3 << 5,       "Non-broadcast" },
+       { 4 << 5,       "All-routes broadcast" },
+       { 5 << 5,       "All-routes broadcast" },
+       { 6 << 5,       "Single-route broadcast" },
+       { 7 << 5,       "Single-route broadcast" },
+       { 0,            NULL }
+};
+
+static const value_string max_frame_size_vals[] = {
+       { 0 << 4,       "516" },
+       { 1 << 4,       "1500" },
+       { 2 << 4,       "2052" },
+       { 3 << 4,       "4472" },
+       { 4 << 4,       "8144" },
+       { 5 << 4,       "11407" },
+       { 6 << 4,       "17800" },
+       { 7 << 4,       "65535" },
+       { 0,            NULL }
+};
+
+static const value_string direction_vals[] = {
+       { 0,    "From originating station (-->)" },
+       { 128,  "To originating station (<--)" },
+       { 0,    NULL }
+};
+
+static dissector_handle_t trmac_handle;
+static dissector_handle_t llc_handle;
+static dissector_handle_t data_handle;
+
+/*
+ * DODGY LINUX HACK DODGY LINUX HACK
+ * Linux 2.0.x always passes frames to the Token Ring driver for transmission with 
+ * 18 bytes padding for source routing information.  Some drivers copy the first 
+ * (18 - srlen) bytes up the frame (18 - srlen) bytes thus removing the padding.
+ * Other drivers just make a copy of the entire frame and then hack about with it
+ * so the frame the sniffer gets is fine (just has extra sr routing).
+ * In the first instance (driver hacking frame in situ) the sniffer gets a garbled
+ * frame.
+ * This function trys to detect this and returns the offset of where
+ * the frame really starts.
+ * This only detects frames that we have sent ourselves so if we are packet sniffing
+ * on the machine we are watching this is useful.
+ * Compare offset 0 with offset x+1 for a length of x bytes for all value of x = 1 to 18
+ * if match then Linux driver has done in situ source route compression of the crappy 
+ * Linux 2.0.x frame so the beginning of the real frame is x bytes in.
+ * (And this real frame x bytes in looks like a proper TR frame that goes on the wire
+ * with none of the Linux idiosyncrasies).
+ */
+int check_for_old_linux_tvb(tvbuff_t *tvb)
+{
+       const guint8    *data;
+       int             x, bytes;
 
-static void
-add_ring_bridge_pairs(int rcf_len, const u_char *pd, proto_tree *tree);
+       /* Restrict our looping to the boundaries of the frame */
+       bytes = tvb_length(tvb);
+       if (bytes > 19) {
+               bytes = 19;
+       }
 
-static char*
-sr_broadcast(u_char val) {
+       data = tvb_get_ptr(tvb, 0, bytes);
 
-       if (val < 4) {
-               return "Non-broadcast";
-       }
-       else if (val < 6) {
-               return "All-routes broadcast";
-       }
-       else {
-               return "Single-route broadcast";
+       for(x = 1; x <= bytes-1 ;x++)
+       {
+               if (memcmp(&data[0], &data[x], x) == 0)
+               {
+                       return x;
+               }
        }
+       return 0;               
 }
 
-static int
-sr_frame(u_char val) {
-
-       int rc_frame[7] = { 516, 1500, 2052, 4472, 8144, 11407, 17800 };
-
-       if (val > 6) {
-               return -1;
+int check_for_old_linux(const u_char * pd)
+{
+       int x;
+       for(x=1;x<=18;x++)
+       {
+               if (memcmp(&pd[0],&pd[x],x) == 0)
+               {
+                       return x;
+               }
        }
-       else return rc_frame[val];
+       return 0;               
 }
 
 
-void
-capture_tr(const u_char *pd, guint32 cap_len, packet_counts *ld) {
+static void
+add_ring_bridge_pairs(int rcf_len, tvbuff_t*, proto_tree *tree);
 
-       int                     offset = 14;
+void
+capture_tr(const u_char *pd, int offset, int len, packet_counts *ld) {
 
        int                     source_routed = 0;
        int                     frame_type;
+       int                     x;
        guint8                  trn_rif_bytes;
        guint8                  actual_rif_bytes;
+       guint16                 first2_sr;
 
        /* The trn_hdr struct, as separate variables */
        guint8                  trn_fc;         /* field control field */
-       guint8                  trn_shost[6];   /* source host */
+       const guint8            *trn_shost;     /* source host */
+
+       if (!BYTES_ARE_IN_FRAME(offset, len, TR_MIN_HEADER_LEN)) {
+               ld->other++;
+               return;
+       }
+
+       if ((x = check_for_old_linux(pd)))
+       {
+               /* Actually packet starts x bytes into what we have got but with all
+                  source routing compressed 
+               */
+                /* pd = &pd[x]; */ offset+=x;
+       }
 
        /* get the data */
-       memcpy(&trn_fc, &pd[1], sizeof(guint8));
-       memcpy(trn_shost, &pd[8], 6 * sizeof(guint8));
+       trn_fc = pd[offset + 1];
+       trn_shost = &pd[offset + 8];
 
        frame_type = (trn_fc & 192) >> 6;
 
@@ -90,36 +216,28 @@ capture_tr(const u_char *pd, guint32 cap_len, packet_counts *ld) {
                this packet is source-routed */
        source_routed = trn_shost[0] & 128;
 
-       trn_rif_bytes = pd[14] & 31;
-
-       /* sometimes we have a RCF but no RIF... half source-routed? */
-       /* I'll check for 2 bytes of RIF and the 0x70 byte */
-       if (!source_routed) {
-               if (trn_rif_bytes == 2) {
-                       source_routed = 1;
-               }
-               /* the Linux 2.0 TR code strips source-route bits in
-                * order to test for SR. This can be removed from most
-                * packets with oltr, but not all. So, I try to figure out
-                * which packets should have been SR here. I'll check to
-                * see if there's a SNAP or IPX field right after
-                * my RIF fields.
-                */
-               else if ( (
-                       pd[0x0e + trn_rif_bytes] == 0xaa &&
-                       pd[0x0f + trn_rif_bytes] == 0xaa &&
-                       pd[0x10 + trn_rif_bytes] == 0x03) ||
-                         (
-                       pd[0x0e + trn_rif_bytes] == 0xe0 &&
-                       pd[0x0f + trn_rif_bytes] == 0xe0) ) {
-
-                       source_routed = 1;
+       trn_rif_bytes = pd[offset + 14] & 31;
+
+       /* the Linux 2.0 TR code strips source-route bits in
+        * order to test for SR. This can be removed from most
+        * packets with oltr, but not all. So, I try to figure out
+        * which packets should have been SR here. I'll check to
+        * see if there's a SNAP or IPX field right after
+        * my RIF fields.
+        */
+       if (!source_routed && trn_rif_bytes > 0) {
+               if (pd[offset + 0x0e] != pd[offset + 0x0f]) {
+                       first2_sr = pntohs(&pd[offset + 0xe0 + trn_rif_bytes]);
+                       if (
+                               (first2_sr == 0xaaaa &&
+                               pd[offset + 0x10 + trn_rif_bytes] == 0x03) ||
+
+                               first2_sr == 0xe0e0 ||
+                               first2_sr == 0xe0aa ) {
+
+                               source_routed = 1;
+                       }
                }
-/*             else {
-                       printf("0e+%d = %02X   0f+%d = %02X\n", trn_rif_bytes, pd[0x0e + trn_rif_bytes],
-                                       trn_rif_bytes, pd[0x0f + trn_rif_bytes]);
-               } */
-
        }
 
        if (source_routed) {
@@ -136,12 +254,29 @@ capture_tr(const u_char *pd, guint32 cap_len, packet_counts *ld) {
        if ((source_routed && trn_rif_bytes == 2 && frame_type == 1) ||
                (!source_routed && frame_type == 1)) {
                /* look for SNAP or IPX only */
-               if ( (pd[0x20] == 0xaa && pd[0x21] == 0xaa && pd[0x22] == 03) ||
-                        (pd[0x20] == 0xe0 && pd[0x21] == 0xe0) ) {
+               if ( (pd[offset + 0x20] == 0xaa && pd[offset + 0x21] == 0xaa && pd[offset + 0x22] == 03) ||
+                        (pd[offset + 0x20] == 0xe0 && pd[offset + 0x21] == 0xe0) ) {
                        actual_rif_bytes = 18;
-               }
+               } else if (
+                       pd[offset + 0x23] == 0 &&
+                       pd[offset + 0x24] == 0 &&
+                       pd[offset + 0x25] == 0 &&
+                       pd[offset + 0x26] == 0x00 &&
+                       pd[offset + 0x27] == 0x11) {
+
+                        actual_rif_bytes = 18;
+
+                       /* Linux 2.0.x also requires drivers pass up a fake SNAP and LLC header before th
+                          real LLC hdr for all Token Ring frames that arrive with DSAP and SSAP != 0xAA
+                          (i.e. for non SNAP frames e.g. for Netware frames)
+                          the fake SNAP header has the ETH_P_TR_802_2 ether type (0x0011) and the protocol id
+                          bytes as zero frame looks like :-
+                          TR Header | Fake LLC | Fake SNAP | Wire LLC | Rest of data */
+                       offset += 8; /* Skip fake LLC and SNAP */
+                }
        }
-       offset += actual_rif_bytes;
+       
+       offset += actual_rif_bytes + TR_MIN_HEADER_LEN;
 
        /* The package is either MAC or LLC */
        switch (frame_type) {
@@ -150,7 +285,7 @@ capture_tr(const u_char *pd, guint32 cap_len, packet_counts *ld) {
                        ld->other++;
                        break;
                case 1:
-                       capture_llc(pd, offset, cap_len, ld);
+                       capture_llc(pd, offset, len, ld);
                        break;
                default:
                        /* non-MAC, non-LLC, i.e., "Reserved" */
@@ -160,106 +295,101 @@ capture_tr(const u_char *pd, guint32 cap_len, packet_counts *ld) {
 }
 
 
-void
-dissect_tr(const u_char *pd, frame_data *fd, proto_tree *tree) {
-
-       proto_tree      *fh_tree, *bf_tree;
+static void
+dissect_tr(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+       proto_tree      *tr_tree, *bf_tree;
        proto_item      *ti;
-       int                     offset = 14;
-
-       int                     source_routed = 0;
-       int                     frame_type;
-       guint8          trn_rif_bytes;
-       guint8          actual_rif_bytes;
+       int             frame_type;
+       guint8          rcf1, rcf2;
+       tvbuff_t        *next_tvb;
+
+       volatile int            fixoffset = 0;
+       volatile int            source_routed = 0;
+       volatile guint8         trn_rif_bytes;
+       volatile guint8         actual_rif_bytes;
+       volatile guint8         c1_nonsr;
+       volatile guint8         c2_nonsr;
+       volatile guint16        first2_sr;
+       tvbuff_t                *volatile tr_tvb;
 
        /* The trn_hdr struct, as separate variables */
        guint8                  trn_ac;         /* access control field */
        guint8                  trn_fc;         /* field control field */
-       guint8                  trn_dhost[6];   /* destination host */
-       guint8                  trn_shost[6];   /* source host */
-       guint16                 trn_rcf;        /* routing control field */
-       guint16                 trn_rseg[8];    /* routing registers */
+       const guint8            *trn_dhost;     /* destination host */
+       const guint8            *trn_shost;     /* source host */
 
        /* non-source-routed version of source addr */
-       guint8                  trn_shost_nonsr[6];
+       static guint8           trn_shost_nonsr[6];
+       int                     x;
+       
+       /* Token-Ring Strings */
+       char *fc[] = { "MAC", "LLC", "Reserved", "Unknown" };
 
+       if (check_col(pinfo->cinfo, COL_PROTOCOL))
+               col_set_str(pinfo->cinfo, COL_PROTOCOL, "TR");
 
-       static const value_string ac_vals[] = {
-               { 0,    "Token" },
-               { 0x10, "Frame" },
-               { 0,    NULL }
-       };
-
-       static const value_string pcf_vals[] = {
-               { 0,    "Normal buffer" },
-               { 1,    "Express buffer" },
-               { 2,    "Purge" },
-               { 3,    "Claim Token" },
-               { 4,    "Beacon" },
-               { 5,    "Active Monitor Present" },
-               { 6,    "Standby Monitor Present" },
-               { 0,    NULL },
-       };
+       if ((x = check_for_old_linux_tvb((tvbuff_t*) tvb))) {
+               /* Actually packet starts x bytes into what we have got but with all
+                  source routing compressed. See comment above */
+               tr_tvb = tvb_new_subset((tvbuff_t*) tvb, x, -1, -1);
+       }
+       else {
+               tr_tvb = tvb;
+       }
 
-       static const value_string frame_vals[] = {
-               { 0,    "MAC" },
-               { 64,   "LLC" },
-               { 128,  "Reserved" },
-               { 0,    NULL },
-       };
+       /* Get the data */
+       trn_fc          = tvb_get_guint8(tr_tvb, 1);
+       trn_dhost       = tvb_get_ptr(tr_tvb, 2, 6);
+       trn_shost       = tvb_get_ptr(tr_tvb, 8, 6);
 
-       /* Token-Ring Strings */
-       char *fc[] = { "MAC", "LLC", "Reserved", "Unknown" };
-       char *rc_arrow[] = { "-->", "<--" };
-       char *rc_direction[] = { "From originating station",
-               "To originating station" };
 
-       /* get the data */
-       memcpy(&trn_ac, &pd[0], sizeof(guint8));
-       memcpy(&trn_fc, &pd[1], sizeof(guint8));
-       memcpy(trn_dhost, &pd[2], 6 * sizeof(guint8));
-       memcpy(trn_shost, &pd[8], 6 * sizeof(guint8));
-       memcpy(&trn_rcf, &pd[14], sizeof(guint16));
-       memcpy(trn_rseg, &pd[16], 8 * sizeof(guint16));
-
-       memcpy(trn_shost_nonsr, &pd[8], 6 * sizeof(guint8));
+       memcpy(trn_shost_nonsr, trn_shost, 6);
        trn_shost_nonsr[0] &= 127;
        frame_type = (trn_fc & 192) >> 6;
 
+       if (check_col(pinfo->cinfo, COL_INFO))
+               col_add_fstr(pinfo->cinfo, COL_INFO, "Token-Ring %s", fc[frame_type]);
+
        /* if the high bit on the first byte of src hwaddr is 1, then
                this packet is source-routed */
        source_routed = trn_shost[0] & 128;
 
-       trn_rif_bytes = pd[14] & 31;
+       trn_rif_bytes = tvb_get_guint8(tr_tvb, 14) & 31;
+
+       /* the Linux 2.0 TR code strips source-route bits in
+        * order to test for SR. This can be removed from most
+        * packets with oltr, but not all. So, I try to figure out
+        * which packets should have been SR here. I'll check to
+        * see if there's a SNAP or IPX field right after
+        * my RIF fields.
+        */
+       if (frame_type == 1 && !source_routed && trn_rif_bytes > 0) {
+               TRY {
+
+                       c1_nonsr = tvb_get_guint8(tr_tvb, 14);
+                       c2_nonsr = tvb_get_guint8(tr_tvb, 15);
+
+                       if (c1_nonsr != c2_nonsr) {
 
-       /* sometimes we have a RCF but no RIF... half source-routed? */
-       /* I'll check for 2 bytes of RIF and the 0x70 byte */
-       if (!source_routed) {
-               if (trn_rif_bytes == 2) {
-                       source_routed = 1;
+                               first2_sr = tvb_get_ntohs(tr_tvb, trn_rif_bytes + 0x0e);
+
+                               if ( ( first2_sr == 0xaaaa &&
+                                       tvb_get_guint8(tr_tvb, trn_rif_bytes + 0x10) == 0x03)   ||
+                                       
+                                       first2_sr == 0xe0e0 || 
+                                       first2_sr == 0xe0aa ) {
+
+                                       source_routed = 1;
+                               }
+                       }
                }
-               /* the Linux 2.0 TR code strips source-route bits in
-                * order to test for SR. This can be removed from most
-                * packets with oltr, but not all. So, I try to figure out
-                * which packets should have been SR here. I'll check to
-                * see if there's a SNAP or IPX field right after
-                * my RIF fields.
-                */
-               else if ( (
-                       pd[0x0e + trn_rif_bytes] == 0xaa &&
-                       pd[0x0f + trn_rif_bytes] == 0xaa &&
-                       pd[0x10 + trn_rif_bytes] == 0x03) ||
-                         (
-                       pd[0x0e + trn_rif_bytes] == 0xe0 &&
-                       pd[0x0f + trn_rif_bytes] == 0xe0) ) {
-
-                       source_routed = 1;
+               CATCH(BoundsError) {
+                       /* We had no information beyond the TR header. Just assume
+                        * this is a normal (non-Linux) TR header. */
+                       ;
                }
-/*             else {
-                       printf("0e+%d = %02X   0f+%d = %02X\n", trn_rif_bytes, pd[0x0e + trn_rif_bytes],
-                                       trn_rif_bytes, pd[0x0f + trn_rif_bytes]);
-               } */
-
+               ENDTRY;
        }
 
        if (source_routed) {
@@ -273,83 +403,96 @@ dissect_tr(const u_char *pd, frame_data *fd, proto_tree *tree) {
        /* this is a silly hack for Linux 2.0.x. Read the comment below,
        in front of the other #ifdef linux. If we're sniffing our own NIC,
         we get a full RIF, sometimes with garbage */
-       if ((source_routed && trn_rif_bytes == 2 && frame_type == 1) ||
-               (!source_routed && frame_type == 1)) {
-               /* look for SNAP or IPX only */
-               if ( (pd[0x20] == 0xaa && pd[0x21] == 0xaa && pd[0x22] == 03) ||
-                        (pd[0x20] == 0xe0 && pd[0x21] == 0xe0) ) {
-                       actual_rif_bytes = 18;
+       TRY {
+               if (frame_type == 1 && ( (source_routed && trn_rif_bytes == 2) ||
+                                        !source_routed) ) {
+                       /* look for SNAP or IPX only */
+                       if (    
+                               (tvb_get_ntohs(tr_tvb, 0x20) == 0xaaaa &&
+                               tvb_get_guint8(tr_tvb, 0x22) == 0x03)
+                        ||
+                               tvb_get_ntohs(tr_tvb, 0x20) == 0xe0e0 ) { 
+
+                               actual_rif_bytes = 18;
+                      }
+                       else if (
+                                       tvb_get_ntohl(tr_tvb, 0x23) == 0 &&
+                                       tvb_get_guint8(tr_tvb, 0x27) == 0x11) {
+
+                               actual_rif_bytes = 18;
+
+                              /* Linux 2.0.x also requires drivers pass up a fake SNAP and LLC header before th
+                                 real LLC hdr for all Token Ring frames that arrive with DSAP and SSAP != 0xAA
+                                 (i.e. for non SNAP frames e.g. for Netware frames)
+                                 the fake SNAP header has the ETH_P_TR_802_2 ether type (0x0011) and the protocol id
+                                 bytes as zero frame looks like :-
+                                 TR Header | Fake LLC | Fake SNAP | Wire LLC | Rest of data */
+                              fixoffset += 8; /* Skip fake LLC and SNAP */
+                       }
                }
        }
-       offset += actual_rif_bytes;
+       CATCH(BoundsError) {
+               /* We had no information beyond the TR header. Just assume
+                * this is a normal (non-Linux) TR header. */
+               ;
+       }
+       ENDTRY;
 
 
-       /* information window */
-       if (check_col(fd, COL_RES_DL_DST))
-               col_add_str(fd, COL_RES_DL_DST, ether_to_str((guint8 *)&pd[2]));
-       if (check_col(fd, COL_RES_DL_SRC))
-               col_add_str(fd, COL_RES_DL_SRC, ether_to_str(trn_shost_nonsr));
-       if (check_col(fd, COL_PROTOCOL))
-               col_add_str(fd, COL_PROTOCOL, "TR");
-       if (check_col(fd, COL_INFO))
-               col_add_fstr(fd, COL_INFO, "Token-Ring %s", fc[frame_type]);
+       /* XXX - copy it to some buffer associated with "*pinfo", rather than
+          just making "trn_shost_nonsr" static? */
+       SET_ADDRESS(&pinfo->dl_src,     AT_ETHER, 6, trn_shost_nonsr);
+       SET_ADDRESS(&pinfo->src,        AT_ETHER, 6, trn_shost_nonsr);
+       SET_ADDRESS(&pinfo->dl_dst,     AT_ETHER, 6, trn_dhost);
+       SET_ADDRESS(&pinfo->dst,        AT_ETHER, 6, trn_dhost);
 
        /* protocol analysis tree */
        if (tree) {
-               ti = proto_tree_add_item(tree, 0, 14 + actual_rif_bytes, "Token-Ring");
-               fh_tree = proto_tree_new();
-               proto_item_add_subtree(ti, fh_tree, ETT_TOKEN_RING);
+               /* Create Token-Ring Tree */
+               ti = proto_tree_add_item(tree, proto_tr, tr_tvb, 0, TR_MIN_HEADER_LEN + actual_rif_bytes, FALSE);
+               tr_tree = proto_item_add_subtree(ti, ett_token_ring);
 
-               ti = proto_tree_add_item(fh_tree, 0, 1, "Access Control (0x%02x)", trn_ac);
-               bf_tree = proto_tree_new();
-               proto_item_add_subtree(ti, bf_tree, ETT_TOKEN_RING_AC);
+               /* Create the Access Control bitfield tree */
+               trn_ac = tvb_get_guint8(tr_tvb, 0);
+               ti = proto_tree_add_uint(tr_tree, hf_tr_ac, tr_tvb, 0, 1, trn_ac);
+               bf_tree = proto_item_add_subtree(ti, ett_token_ring_ac);
 
-               proto_tree_add_item(bf_tree, 0, 1, "%s",
-                       decode_numeric_bitfield(trn_ac, 0xe0, 8, "Priority = %d"));
+               proto_tree_add_uint(bf_tree, hf_tr_priority, tr_tvb, 0, 1, trn_ac);
+               proto_tree_add_boolean(bf_tree, hf_tr_frame, tr_tvb, 0, 1, trn_ac);
+               proto_tree_add_uint(bf_tree, hf_tr_monitor_cnt, tr_tvb, 0, 1, trn_ac);
+               proto_tree_add_uint(bf_tree, hf_tr_priority_reservation, tr_tvb, 0, 1, trn_ac);
 
-               proto_tree_add_item(bf_tree, 0, 1, "%s",
-                       decode_enumerated_bitfield(trn_ac, 0x10, 8, ac_vals, "%s"));
+               /* Create the Frame Control bitfield tree */
+               ti = proto_tree_add_uint(tr_tree, hf_tr_fc, tr_tvb, 1, 1, trn_fc);
+               bf_tree = proto_item_add_subtree(ti, ett_token_ring_fc);
 
-               proto_tree_add_item(bf_tree, 0, 1, "%s",
-                       decode_numeric_bitfield(trn_ac, 0x08, 8, "Monitor Count"));
+               proto_tree_add_uint(bf_tree, hf_tr_fc_type, tr_tvb, 1, 1, trn_fc);
+               proto_tree_add_uint(bf_tree, hf_tr_fc_pcf, tr_tvb,  1, 1, trn_fc);
+               proto_tree_add_ether(tr_tree, hf_tr_dst, tr_tvb, 2, 6, trn_dhost);
+               proto_tree_add_ether(tr_tree, hf_tr_src, tr_tvb, 8, 6, trn_shost);
+               proto_tree_add_ether_hidden(tr_tree, hf_tr_addr, tr_tvb, 2, 6, trn_dhost);
+               proto_tree_add_ether_hidden(tr_tree, hf_tr_addr, tr_tvb, 8, 6, trn_shost);
 
-               proto_tree_add_item(bf_tree, 0, 1, "%s",
-                       decode_numeric_bitfield(trn_ac, 0x07, 8, "Priority Reservation = %d"));
+               proto_tree_add_boolean(tr_tree, hf_tr_sr, tr_tvb, 8, 1, source_routed);
 
-
-               ti = proto_tree_add_item(fh_tree, 1, 1, "Frame Control (0x%02x)", trn_fc);
-               bf_tree = proto_tree_new();
-               proto_item_add_subtree(ti, bf_tree, ETT_TOKEN_RING_FC);
-
-               proto_tree_add_item(bf_tree, 1, 1, "%s",
-                       decode_enumerated_bitfield(trn_fc, 0xc0, 8, frame_vals, "%s"));
-
-               proto_tree_add_item(bf_tree, 1, 1, "%s",
-                       decode_enumerated_bitfield(trn_fc, 0x0f, 8, pcf_vals, "%s"));
-
-               proto_tree_add_item(fh_tree, 2, 6, "Destination: %s",
-                       ether_to_str((guint8 *) trn_dhost));
-               proto_tree_add_item(fh_tree, 8, 6, "Source: %s",
-                       ether_to_str((guint8 *) trn_shost));
+               /* non-source-routed version of src addr */
+               proto_tree_add_ether_hidden(tr_tree, hf_tr_src, tr_tvb, 8, 6, trn_shost_nonsr);
 
                if (source_routed) {
-                       proto_tree_add_item(fh_tree, 14, 1, "RIF length: %d bytes", trn_rif_bytes);
-
-                       proto_tree_add_item(fh_tree, 15, 1,
-                               "%s, up to %d bytes in frame (LF=%d)",
-                               sr_broadcast((pd[14] & 224) >> 5),
-                               sr_frame((pd[15] & 112) >> 4),
-                               (pd[15] & 112) >> 4);
+                       /* RCF Byte 1 */
+                       rcf1 = tvb_get_guint8(tr_tvb, 14);
+                       proto_tree_add_uint(tr_tree, hf_tr_rif_bytes, tr_tvb, 14, 1, trn_rif_bytes);
+                       proto_tree_add_uint(tr_tree, hf_tr_broadcast, tr_tvb, 14, 1, rcf1 & 224);
 
-                       proto_tree_add_item(fh_tree, 15, 1,
-                               "Direction: %s (%s)",
-                               rc_direction[(pd[15] & 128) >> 7],
-                               rc_arrow[(pd[15] & 128) >> 7]);
+                       /* RCF Byte 2 */
+                       rcf2 = tvb_get_guint8(tr_tvb, 15);
+                       proto_tree_add_uint(tr_tree, hf_tr_max_frame_size, tr_tvb, 15, 1, rcf2 & 112);
+                       proto_tree_add_uint(tr_tree, hf_tr_direction, tr_tvb, 15, 1, rcf2 & 128);
 
                        /* if we have more than 2 bytes of RIF, then we have
                                ring/bridge pairs */
                        if (trn_rif_bytes > 2) {
-                               add_ring_bridge_pairs(trn_rif_bytes, pd, fh_tree);
+                               add_ring_bridge_pairs(trn_rif_bytes, tr_tvb, tr_tree);
                        }
                }
 
@@ -361,72 +504,185 @@ dissect_tr(const u_char *pd, frame_data *fd, proto_tree *tree) {
                are filled with garbage. The best way to detect this problem is
                to know the src hwaddr of the machine from which you were running
                tcpdump. W/o that, however, I'm guessing that DSAP == SSAP if the
-               frame type is LLC.  It's very much a hack. -- Gilbert Ramirez */
+               frame type is LLC.  It's very much a hack. */
                if (actual_rif_bytes > trn_rif_bytes) {
-                       /*printf("trn_rif %d    actual_rif %d\n", trn_rif_bytes, actual_rif_bytes);*/
-                       proto_tree_add_item(fh_tree, 14 + trn_rif_bytes, actual_rif_bytes - trn_rif_bytes,
+                       proto_tree_add_text(tr_tree, tr_tvb, TR_MIN_HEADER_LEN + trn_rif_bytes, actual_rif_bytes - trn_rif_bytes,
                                "Empty RIF from Linux 2.0.x driver. The sniffing NIC "
                                "is also running a protocol stack.");
                }
-               /*
-               if (source_routed && (trn_rif_bytes == 2) && silly_linux) {
-                       proto_tree_add_item(fh_tree, 14 + trn_rif_bytes, 18 - actual_rif_bytes,
-                               "Empty RIF from Linux 2.0.x driver. The sniffing NIC "
-                               "is also running a protocol stack.");
+               if (fixoffset) {
+                       proto_tree_add_text(tr_tree, tr_tvb, TR_MIN_HEADER_LEN + 18,8,"Linux 2.0.x fake LLC and SNAP header");
                }
-               else if ((!source_routed) && silly_linux ) {
-                       proto_tree_add_item(fh_tree, 14, 18,
-                               "Empty RIF from Linux 2.0.x driver. The sniffing NIC "
-                               "is also running a protocol stack.");
-               }*/
        }
 
+       next_tvb = tvb_new_subset(tr_tvb, TR_MIN_HEADER_LEN + actual_rif_bytes + fixoffset, -1, -1);
+
        /* The package is either MAC or LLC */
        switch (frame_type) {
                /* MAC */
                case 0:
-                       dissect_trmac(pd, offset, fd, tree);
+                       call_dissector(trmac_handle, next_tvb, pinfo, tree);
                        break;
                case 1:
-                       dissect_llc(pd, offset, fd, tree);
+                       call_dissector(llc_handle, next_tvb, pinfo, tree);
                        break;
                default:
                        /* non-MAC, non-LLC, i.e., "Reserved" */
-                       dissect_data(pd, offset, fd, tree);
+                       call_dissector(data_handle,next_tvb, pinfo, tree);
                        break;
        }
 }
 
 /* this routine is taken from the Linux net/802/tr.c code, which shows
-ring-bridge paires in the /proc/net/tr_rif virtual file. */
+ring-bridge pairs in the /proc/net/tr_rif virtual file. */
 static void
-add_ring_bridge_pairs(int rcf_len, const u_char *pd, proto_tree *tree)
+add_ring_bridge_pairs(int rcf_len, tvbuff_t *tvb, proto_tree *tree)
 {
        int     j, size;
-       int     segment, brdgnmb;
-       char    buffer[50];
-       int             buff_offset=0;
+       int     segment, brdgnmb, unprocessed_rif;
+       int     buff_offset=0;
 
-       rcf_len -= 2;
+#define RIF_OFFSET             16
+#define RIF_BYTES_TO_PROCESS   30
 
-       if (rcf_len)
-               rcf_len >>= 1;
+       char    buffer[3 + (RIF_BYTES_TO_PROCESS / 2) * 6 + 1];
 
-       for(j = 1; j < rcf_len; j++) {
+       /* Only process so many  bytes of RIF, as per TR spec, and not overflow
+        * static buffer above */
+       unprocessed_rif = rcf_len - RIF_BYTES_TO_PROCESS;
+       rcf_len = MIN(rcf_len, RIF_BYTES_TO_PROCESS);
+
+       /* Ignore the 2 RCF bytes, since they don't make up the ring/bride pairs */
+       rcf_len -= 2;
+
+       for(j = 1; j < rcf_len - 1; j += 2) {
                if (j==1) {
-                       segment=pntohs(&pd[16]) >> 4;
+                       segment = tvb_get_ntohs(tvb, RIF_OFFSET) >> 4;
                        size = sprintf(buffer, "%03X",segment);
+                       proto_tree_add_uint_hidden(tree, hf_tr_rif_ring, tvb, TR_MIN_HEADER_LEN + 2, 2, segment);
                        buff_offset += size;
                }
-               segment=pntohs(&pd[17+j]) >> 4;
-               brdgnmb=pd[16+j] & 0x0f;
+               segment = tvb_get_ntohs(tvb, RIF_OFFSET + 1 + j) >> 4;
+               brdgnmb = tvb_get_guint8(tvb, RIF_OFFSET + j) & 0x0f;
                size = sprintf(buffer+buff_offset, "-%01X-%03X",brdgnmb,segment);
+               proto_tree_add_uint_hidden(tree, hf_tr_rif_ring, tvb, TR_MIN_HEADER_LEN + 3 + j, 2, segment);
+               proto_tree_add_uint_hidden(tree, hf_tr_rif_bridge, tvb, TR_MIN_HEADER_LEN + 2 + j, 1, brdgnmb);
                buff_offset += size;    
        }
+       proto_tree_add_string(tree, hf_tr_rif, tvb, TR_MIN_HEADER_LEN + 2, rcf_len, buffer);
 
-       proto_tree_add_item(tree, 16, rcf_len << 1,
-               "Ring-Bridge Pairs: %s",
-               buffer);
+       if (unprocessed_rif > 0) {
+               proto_tree_add_text(tree, tvb, TR_MIN_HEADER_LEN + RIF_BYTES_TO_PROCESS, unprocessed_rif,
+                               "Extra RIF bytes beyond spec: %d", unprocessed_rif);
+       }
+}
 
+void
+proto_register_tr(void)
+{
+       static hf_register_info hf[] = {
+               { &hf_tr_ac,
+               { "Access Control",     "tr.ac", FT_UINT8, BASE_HEX, NULL, 0x0,
+                       "", HFILL }},
+
+               { &hf_tr_priority,
+               { "Priority",           "tr.priority", FT_UINT8, BASE_DEC, NULL, 0xe0,
+                       "", HFILL }},
+
+               { &hf_tr_frame,
+               { "Frame",              "tr.frame", FT_BOOLEAN, 8, TFS(&ac_truth), 0x10,
+                       "", HFILL }},
+
+               { &hf_tr_monitor_cnt,
+               { "Monitor Count",      "tr.monitor_cnt", FT_UINT8, BASE_DEC, NULL, 0x08,
+                       "", HFILL }},
+
+               { &hf_tr_priority_reservation,
+               { "Priority Reservation","tr.priority_reservation", FT_UINT8, BASE_DEC, NULL, 0x07,
+                       "", HFILL }},
+
+               { &hf_tr_fc,
+               { "Frame Control",      "tr.fc", FT_UINT8, BASE_HEX, NULL, 0x0,
+                       "", HFILL }},
+
+               { &hf_tr_fc_type,
+               { "Frame Type",         "tr.frame_type", FT_UINT8, BASE_DEC, VALS(frame_vals), 0xc0,
+                       "", HFILL }},
+
+               { &hf_tr_fc_pcf,
+               { "Frame PCF",          "tr.frame_pcf", FT_UINT8, BASE_DEC, VALS(pcf_vals), 0x0f,
+                       "", HFILL }},
+
+               { &hf_tr_dst,
+               { "Destination",        "tr.dst", FT_ETHER, BASE_NONE,  NULL, 0x0,
+                       "Destination Hardware Address", HFILL }},
+
+               { &hf_tr_src,
+               { "Source",             "tr.src", FT_ETHER, BASE_NONE, NULL, 0x0,
+                       "Source Hardware Address", HFILL }},
+
+               { &hf_tr_addr,
+               { "Source or Destination Address", "tr.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
+                       "Source or Destination Hardware Address", HFILL }},
+
+               { &hf_tr_sr,
+               { "Source Routed",      "tr.sr", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+                       "Source Routed", HFILL }},
+
+               { &hf_tr_rif_bytes,
+               { "RIF Bytes",          "tr.rif_bytes", FT_UINT8, BASE_DEC, NULL, 0x0,
+                       "Number of bytes in Routing Information Fields, including "
+                       "the two bytes of Routing Control Field", HFILL }},
+
+               { &hf_tr_broadcast,
+               { "Broadcast Type",     "tr.broadcast", FT_UINT8, BASE_DEC, VALS(broadcast_vals), 0x0,
+                       "Type of Token-Ring Broadcast", HFILL }},
+
+               { &hf_tr_max_frame_size,
+               { "Maximum Frame Size", "tr.max_frame_size", FT_UINT8, BASE_DEC, VALS(max_frame_size_vals),
+                       0x0,
+                       "", HFILL }},
+
+               { &hf_tr_direction,
+               { "Direction",          "tr.direction", FT_UINT8, BASE_DEC, VALS(direction_vals), 0x0,
+                       "Direction of RIF", HFILL }},
+
+               { &hf_tr_rif,
+               { "Ring-Bridge Pairs",  "tr.rif", FT_STRING, BASE_NONE, NULL, 0x0,
+                       "String representing Ring-Bridge Pairs", HFILL }},
+
+               { &hf_tr_rif_ring,
+               { "RIF Ring",           "tr.rif.ring", FT_UINT16, BASE_HEX, NULL, 0x0,
+                       "", HFILL }},
+
+               { &hf_tr_rif_bridge,
+               { "RIF Bridge",         "tr.rif.bridge", FT_UINT8, BASE_HEX, NULL, 0x0,
+                       "", HFILL }},
+       };
+       static gint *ett[] = {
+               &ett_token_ring,
+               &ett_token_ring_ac,
+               &ett_token_ring_fc,
+       };
+
+       proto_tr = proto_register_protocol("Token-Ring", "Token-Ring", "tr");
+       proto_register_field_array(proto_tr, hf, array_length(hf));
+       proto_register_subtree_array(ett, array_length(ett));
+       register_dissector("tr", dissect_tr, proto_tr);
 }
 
+void
+proto_reg_handoff_tr(void)
+{
+       dissector_handle_t tr_handle;
+
+       /*
+        * Get handles for the TR MAC and LLC dissectors.
+        */
+       trmac_handle = find_dissector("trmac");
+       llc_handle = find_dissector("llc");
+       data_handle = find_dissector("data");
+
+       tr_handle = find_dissector("tr");
+       dissector_add("wtap_encap", WTAP_ENCAP_TOKEN_RING, tr_handle);
+}