/* packet-tr.c * Routines for Token-Ring packet disassembly * Gilbert Ramirez * * $Id: packet-tr.c,v 1.15 1999/07/07 22:51:56 gram Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * 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 * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #ifdef HAVE_SYS_TYPES_H # include #endif #include #include #include "packet.h" #include "etypes.h" int proto_tr = -1; int hf_tr_dst = -1; int hf_tr_src = -1; int hf_tr_dst_vendor = -1; int hf_tr_src_vendor = -1; int hf_tr_sr = -1; int hf_tr_ac = -1; int hf_tr_priority = -1; int hf_tr_frame = -1; int hf_tr_monitor_cnt = -1; int hf_tr_priority_reservation = -1; int hf_tr_fc = -1; int hf_tr_fc_type = -1; int hf_tr_fc_pcf = -1; int hf_tr_rif_bytes = -1; int hf_tr_broadcast = -1; int hf_tr_max_frame_size = -1; int hf_tr_direction = -1; int hf_tr_rif = -1; int hf_tr_rif_ring = -1; int hf_tr_rif_bridge = -1; 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 }, }; static const value_string frame_vals[] = { { 0, "MAC" }, { 64, "LLC" }, { 128, "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, "516" }, { 1, "1500" }, { 2, "2052" }, { 3, "4472" }, { 4, "8144" }, { 5, "11407" }, { 6, "17800" }, { 0, NULL } }; static const value_string direction_vals[] = { { 0, "From originating station (-->)" }, { 128, "To originating station (<--)" }, { 0, NULL } }; static void add_ring_bridge_pairs(int rcf_len, const u_char *pd, proto_tree *tree); void capture_tr(const u_char *pd, guint32 cap_len, packet_counts *ld) { int offset = 14; int source_routed = 0; int frame_type; guint8 trn_rif_bytes; guint8 actual_rif_bytes; /* The trn_hdr struct, as separate variables */ guint8 trn_fc; /* field control field */ guint8 trn_shost[6]; /* source host */ /* get the data */ memcpy(&trn_fc, &pd[1], sizeof(guint8)); memcpy(trn_shost, &pd[8], 6 * sizeof(guint8)); frame_type = (trn_fc & 192) >> 6; /* 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; /* 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 && trn_rif_bytes > 0) { 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; } } if (source_routed) { actual_rif_bytes = trn_rif_bytes; } else { trn_rif_bytes = 0; actual_rif_bytes = 0; } /* 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; } } offset += actual_rif_bytes; /* The package is either MAC or LLC */ switch (frame_type) { /* MAC */ case 0: ld->other++; break; case 1: capture_llc(pd, offset, cap_len, ld); break; default: /* non-MAC, non-LLC, i.e., "Reserved" */ ld->other++; break; } } void dissect_tr(const u_char *pd, frame_data *fd, 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; /* 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 */ /* non-source-routed version of source addr */ guint8 trn_shost_nonsr[6]; /* Token-Ring Strings */ char *fc[] = { "MAC", "LLC", "Reserved", "Unknown" }; /* 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)); trn_shost_nonsr[0] &= 127; frame_type = (trn_fc & 192) >> 6; /* 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; /* 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 && trn_rif_bytes > 0) { 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; } /* 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) { actual_rif_bytes = trn_rif_bytes; } else { trn_rif_bytes = 0; actual_rif_bytes = 0; } /* 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; } } offset += actual_rif_bytes; /* 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]); /* protocol analysis tree */ if (tree) { /* Create Token-Ring Tree */ ti = proto_tree_add_item(tree, proto_tr, 0, 14 + actual_rif_bytes, NULL); tr_tree = proto_item_add_subtree(ti, ETT_TOKEN_RING); /* Create the Access Control bitfield tree */ ti = proto_tree_add_item_format(tr_tree, hf_tr_ac, 0, 1, trn_ac, "Access Control (0x%02x)", trn_ac); bf_tree = proto_item_add_subtree(ti, ETT_TOKEN_RING_AC); proto_tree_add_item_format(bf_tree, hf_tr_priority, 0, 1, trn_ac & 0xe0, decode_numeric_bitfield(trn_ac, 0xe0, 8, "Priority = %d")); proto_tree_add_item_format(bf_tree, hf_tr_frame, 0, 1, trn_ac & 0x10, decode_enumerated_bitfield(trn_ac, 0x10, 8, ac_vals, "%s")); proto_tree_add_item_format(bf_tree, hf_tr_monitor_cnt, 0, 1, trn_ac & 0x08, decode_numeric_bitfield(trn_ac, 0x08, 8, "Monitor Count")); proto_tree_add_item_format(bf_tree, hf_tr_priority_reservation, 0, 1, trn_ac & 0x07, decode_numeric_bitfield(trn_ac, 0x07, 8, "Priority Reservation = %d")); /* Create the Frame Control bitfield tree */ ti = proto_tree_add_item_format(tr_tree, hf_tr_fc, 1, 1, trn_fc, "Frame Control (0x%02x)", trn_fc); bf_tree = proto_item_add_subtree(ti, ETT_TOKEN_RING_FC); proto_tree_add_item_format(bf_tree, hf_tr_fc_type, 1, 1, trn_fc & 0xc0, decode_enumerated_bitfield(trn_fc, 0xc0, 8, frame_vals, "%s")); proto_tree_add_item_format(bf_tree, hf_tr_fc_pcf, 1, 1, trn_fc & 0x0f, decode_enumerated_bitfield(trn_fc, 0x0f, 8, pcf_vals, "%s")); proto_tree_add_item(tr_tree, hf_tr_dst, 2, 6, trn_dhost); proto_tree_add_item_hidden(tr_tree, hf_tr_dst_vendor, 2, 3, trn_dhost); proto_tree_add_item(tr_tree, hf_tr_src, 8, 6, trn_shost); proto_tree_add_item_hidden(tr_tree, hf_tr_src_vendor, 8, 3, trn_shost); proto_tree_add_item_hidden(tr_tree, hf_tr_sr, 8, 1, source_routed); /* non-source-routed version of src addr */ proto_tree_add_item_hidden(tr_tree, hf_tr_src, 8, 6, trn_shost_nonsr); proto_tree_add_item_hidden(tr_tree, hf_tr_src_vendor, 8, 3, trn_shost_nonsr); if (source_routed) { /* RCF Byte 1 */ proto_tree_add_item(tr_tree, hf_tr_rif_bytes, 14, 1, trn_rif_bytes); proto_tree_add_item(tr_tree, hf_tr_broadcast, 14, 1, pd[14] & 224); /* RCF Byte 2 */ proto_tree_add_item(tr_tree, hf_tr_max_frame_size, 15, 1, pd[15] & 112); proto_tree_add_item(tr_tree, hf_tr_direction, 15, 1, pd[15] & 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, tr_tree); } } /* Linux 2.0.x has a problem in that the 802.5 code creates an emtpy full (18-byte) RIF area. It's up to the tr driver to either fill it in or remove it before sending the bytes out to the wire. If you run tcpdump on a Linux 2.0.x machine running token-ring, tcpdump will capture these 18 filler bytes. They 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 */ if (actual_rif_bytes > trn_rif_bytes) { proto_tree_add_text(tr_tree, 14 + 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."); } } /* The package is either MAC or LLC */ switch (frame_type) { /* MAC */ case 0: dissect_trmac(pd, offset, fd, tree); break; case 1: dissect_llc(pd, offset, fd, tree); break; default: /* non-MAC, non-LLC, i.e., "Reserved" */ dissect_data(pd, offset, fd, 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. */ static void add_ring_bridge_pairs(int rcf_len, const u_char *pd, proto_tree *tree) { int j, size; int segment, brdgnmb; char buffer[50]; int buff_offset=0; rcf_len -= 2; if (rcf_len) rcf_len >>= 1; for(j = 1; j < rcf_len; j++) { if (j==1) { segment=pntohs(&pd[16]) >> 4; size = sprintf(buffer, "%03X",segment); proto_tree_add_item_hidden(tree, hf_tr_rif_ring, 16, 2, segment); buff_offset += size; } segment=pntohs(&pd[17+j]) >> 4; brdgnmb=pd[16+j] & 0x0f; size = sprintf(buffer+buff_offset, "-%01X-%03X",brdgnmb,segment); proto_tree_add_item_hidden(tree, hf_tr_rif_ring, 17+j, 2, segment); proto_tree_add_item_hidden(tree, hf_tr_rif_bridge, 16+j, 1, brdgnmb); buff_offset += size; } proto_tree_add_item(tree, hf_tr_rif, 16, rcf_len << 1, buffer); } void proto_register_tr(void) { const hf_register_info hf[] = { { "Access Control", "tr.ac", &hf_tr_ac, FT_UINT8, NULL }, { "Priority", "tr.priority", &hf_tr_priority, FT_UINT8, NULL }, { "Frame", "tr.frame", &hf_tr_frame, FT_VALS_UINT8, VALS(ac_vals) }, { "Monitor Count", "tr.monitor_cnt", &hf_tr_monitor_cnt, FT_UINT8, NULL }, { "Priority Reservation","tr.priority_reservation", &hf_tr_priority_reservation, FT_UINT8, NULL }, { "Frame Control", "tr.fc", &hf_tr_fc, FT_UINT8, NULL }, { "Frame Type", "tr.frame_type", &hf_tr_fc_type, FT_VALS_UINT8, VALS(frame_vals) }, { "Frame PCF", "tr.frame_pcf", &hf_tr_fc_pcf, FT_VALS_UINT8, VALS(pcf_vals) }, { "Destination", "tr.dst", &hf_tr_dst, FT_ETHER, NULL }, { "Source", "tr.src", &hf_tr_src, FT_ETHER, NULL }, { "Destination Hardware Vendor", "tr.dst_vendor", &hf_tr_dst_vendor, FT_ETHER_VENDOR, NULL }, { "Source Hardware Vendor", "tr.src_vendor", &hf_tr_src_vendor, FT_ETHER_VENDOR, NULL }, { "Source Routed", "tr.sr", &hf_tr_sr, FT_BOOLEAN, NULL }, { "RIF Bytes", "tr.rif_bytes", &hf_tr_rif_bytes, FT_UINT8, NULL }, { "Broadcast Type", "tr.broadcast", &hf_tr_broadcast, FT_VALS_UINT8, VALS(broadcast_vals) }, { "Maximum Frame Size", "tr.max_frame_size", &hf_tr_max_frame_size, FT_VALS_UINT8, VALS(max_frame_size_vals) }, { "Direction", "tr.direction", &hf_tr_direction, FT_VALS_UINT8, VALS(direction_vals) }, { "Ring-Bridge Pairs", "tr.rif", &hf_tr_rif, FT_STRING, NULL }, { "RIF Ring", "tr.rif_ring", &hf_tr_rif_ring, FT_UINT16, NULL }, { "RIF Bridge", "tr.rif_bridge", &hf_tr_rif_bridge, FT_UINT8, NULL }, }; proto_tr = proto_register_protocol("Token-Ring", "tr"); proto_register_field_array(proto_tr, hf, array_length(hf)); }