/* packet-udp.c * Routines for UDP packet disassembly * * $Id: packet-udp.c,v 1.41 1999/12/07 06:10:00 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * Richard Sharpe, 13-Feb-1999, added dispatch table support and * support for tftp. * * 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 #ifdef HAVE_NETINET_IN_H # include #endif #include #include #include #include "packet.h" #include "resolv.h" static int proto_udp = -1; static int hf_udp_srcport = -1; static int hf_udp_dstport = -1; static int hf_udp_port = -1; static int hf_udp_length = -1; static int hf_udp_checksum = -1; static gint ett_udp = -1; /* UDP structs and definitions */ typedef struct _e_udphdr { guint16 uh_sport; guint16 uh_dport; guint16 uh_ulen; guint16 uh_sum; } e_udphdr; /* UDP Ports -> should go in packet-udp.h */ #define UDP_PORT_TACACS 49 #define UDP_PORT_DNS 53 #define UDP_PORT_BOOTPS 67 #define UDP_PORT_TFTP 69 #define UDP_PORT_IPX 213 #define UDP_PORT_NTP 123 #define UDP_PORT_NBNS 137 #define UDP_PORT_NBDGM 138 #define UDP_PORT_SNMP 161 #define UDP_PORT_SRVLOC 427 #define UDP_PORT_PIM_RP_DISC 496 #define UDP_PORT_ISAKMP 500 #define UDP_PORT_RIP 520 #define UDP_PORT_RIPNG 521 #define UDP_PORT_NCP 524 #define UDP_PORT_VINES 573 #define UDP_PORT_RADIUS 1645 #define UDP_PORT_RADIUS_NEW 1812 #define UDP_PORT_RADACCT 1646 #define UDP_PORT_RADACCT_NEW 1813 #define UDP_PORT_HSRP 1985 #define UDP_PORT_ICP 3130 #define UDP_PORT_ICQ 4000 #define UDP_PORT_SAP 9875 #define UDP_PORT_RX_LOW 7000 #define UDP_PORT_RX_HIGH 7009 #define UDP_PORT_RX_AFS_BACKUPS 7021 struct hash_struct { guint16 proto; void (*dissect)(const u_char *, int, frame_data *, proto_tree *); struct hash_struct *next; }; static struct hash_struct *hash_table[256]; /* * These routines are for UDP, will be generalized soon: RJS * * XXX - note that they should probably check the IP address as well as * the port number, so that we don't mistakenly identify packets as, say, * TFTP, merely because they have a source or destination port number * equal to the port being used by a TFTP daemon on some machine other * than the one they're going to or from. */ struct hash_struct *udp_find_hash_ent(guint16 proto) { int idx = proto % 256; struct hash_struct *hash_ent = hash_table[idx]; while (hash_ent != NULL) { if (hash_ent -> proto == proto) return hash_ent; hash_ent = hash_ent -> next; } return NULL; } void udp_hash_add(guint16 proto, void (*dissect)(const u_char *, int, frame_data *, proto_tree *)) { int idx = proto % 256; /* Simply take the remainder, hope for no collisions */ struct hash_struct *hash_ent = (struct hash_struct *)malloc(sizeof(struct hash_struct)); struct hash_struct *hash_ent2; hash_ent -> proto = proto; hash_ent -> dissect = dissect; hash_ent -> next = NULL; if (hash_ent == NULL) { fprintf(stderr, "Could not allocate space for hash structure in dissect_udp\n"); exit(1); } if (hash_table[idx]) { /* Something, add on end */ hash_ent2 = hash_table[idx]; while (hash_ent2 -> next != NULL) hash_ent2 = hash_ent2 -> next; hash_ent2 -> next = hash_ent; /* Bad in pathalogical cases */ } else { hash_table[idx] = hash_ent; } } void init_dissect_udp(void) { int i; for (i = 0; i < 256; i++) { hash_table[i] = NULL; } /* Now add the protocols we know about */ udp_hash_add(UDP_PORT_BOOTPS, dissect_bootp); udp_hash_add(UDP_PORT_TFTP, dissect_tftp); udp_hash_add(UDP_PORT_SAP, dissect_sap); udp_hash_add(UDP_PORT_HSRP, dissect_hsrp); udp_hash_add(UDP_PORT_PIM_RP_DISC, dissect_auto_rp); udp_hash_add(UDP_PORT_TACACS, dissect_tacacs); } void dissect_udp(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) { e_udphdr uh; guint16 uh_sport, uh_dport, uh_ulen, uh_sum; struct hash_struct *dissect_routine = NULL; proto_tree *udp_tree; proto_item *ti; if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) { dissect_data(pd, offset, fd, tree); return; } /* Avoids alignment problems on many architectures. */ memcpy(&uh, &pd[offset], sizeof(e_udphdr)); uh_sport = ntohs(uh.uh_sport); uh_dport = ntohs(uh.uh_dport); uh_ulen = ntohs(uh.uh_ulen); uh_sum = ntohs(uh.uh_sum); if (check_col(fd, COL_PROTOCOL)) col_add_str(fd, COL_PROTOCOL, "UDP"); if (check_col(fd, COL_INFO)) col_add_fstr(fd, COL_INFO, "Source port: %s Destination port: %s", get_udp_port(uh_sport), get_udp_port(uh_dport)); if (tree) { ti = proto_tree_add_item(tree, proto_udp, offset, 8); udp_tree = proto_item_add_subtree(ti, ett_udp); proto_tree_add_item_format(udp_tree, hf_udp_srcport, offset, 2, uh_sport, "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport); proto_tree_add_item_format(udp_tree, hf_udp_dstport, offset + 2, 2, uh_dport, "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport); proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset, 2, uh_sport); proto_tree_add_item_hidden(udp_tree, hf_udp_port, offset+2, 2, uh_dport); proto_tree_add_item(udp_tree, hf_udp_length, offset + 4, 2, uh_ulen); proto_tree_add_item_format(udp_tree, hf_udp_checksum, offset + 6, 2, uh_sum, "Checksum: 0x%04x", uh_sum); } /* Skip over header */ offset += 8; pi.ptype = PT_UDP; pi.srcport = uh_sport; pi.destport = uh_dport; /* ONC RPC. We can't base this on anything in the UDP header; we have to look at the payload. If "dissect_rpc()" returns TRUE, it was an RPC packet, otherwise it's some other type of packet. */ if (dissect_rpc(pd, offset, fd, tree)) return; /* XXX - we should do all of this through the table of ports. */ #define PORT_IS(port) (uh_sport == port || uh_dport == port) if (PORT_IS(UDP_PORT_BOOTPS)) dissect_bootp(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_DNS)) dissect_dns(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_SRVLOC)) dissect_srvloc(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_ISAKMP)) dissect_isakmp(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_RIP)) { /* we should check the source port too (RIP: UDP src and dst port 520) */ dissect_rip(pd, offset, fd, tree); } else if (PORT_IS(UDP_PORT_RIPNG)) dissect_ripng(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_NCP)) dissect_ncp(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_NBNS)) dissect_nbns(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_NBDGM)) dissect_nbdgm(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_NTP)) dissect_ntp(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_IPX)) /* RFC 1234 */ dissect_ipx(pd, offset, fd, tree); else if ((uh_sport >= UDP_PORT_RX_LOW && uh_sport <= UDP_PORT_RX_HIGH) || (uh_dport >= UDP_PORT_RX_LOW && uh_dport <= UDP_PORT_RX_HIGH) || PORT_IS(UDP_PORT_RX_AFS_BACKUPS)) dissect_rx(pd, offset, fd, tree); /* transarc AFS's RX protocol */ else if (PORT_IS(UDP_PORT_SNMP)) dissect_snmp(pd, offset, fd, tree); else if (PORT_IS(UDP_PORT_VINES)) { /* FIXME: AFAIK, src and dst port must be the same */ dissect_vines_frp(pd, offset, fd, tree); } else if (PORT_IS(UDP_PORT_TFTP)) { /* This is the first point of call, but it adds a dynamic call */ udp_hash_add(MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */ dissect_tftp(pd, offset, fd, tree); } else if (PORT_IS(UDP_PORT_RADIUS) || PORT_IS(UDP_PORT_RADACCT) || PORT_IS(UDP_PORT_RADIUS_NEW) || PORT_IS(UDP_PORT_RADACCT_NEW) ) { dissect_radius(pd, offset, fd, tree); } else if ( PORT_IS(UDP_PORT_ICP)) { dissect_icp(pd,offset,fd,tree); } else if ( PORT_IS(UDP_PORT_ICQ)) { dissect_icq(pd,offset,fd,tree); } else { /* OK, find a routine in the table, else use the default */ if ((dissect_routine = udp_find_hash_ent(uh_sport))) { struct hash_struct *dr2 = udp_find_hash_ent(uh_dport); if (dr2 == NULL) { /* Not in the table, add */ udp_hash_add(uh_dport, dissect_tftp); } dissect_routine -> dissect(pd, offset, fd, tree); } else if ((dissect_routine = udp_find_hash_ent(uh_dport))) { dissect_routine -> dissect(pd, offset, fd, tree); } else { dissect_data(pd, offset, fd, tree); } } } void proto_register_udp(void) { static hf_register_info hf[] = { { &hf_udp_srcport, { "Source Port", "udp.srcport", FT_UINT16, BASE_DEC, NULL, 0x0, "" }}, { &hf_udp_dstport, { "Destination Port", "udp.dstport", FT_UINT16, BASE_DEC, NULL, 0x0, "" }}, { &hf_udp_port, { "Source or Destination Port", "udp.port", FT_UINT16, BASE_DEC, NULL, 0x0, "" }}, { &hf_udp_length, { "Length", "udp.length", FT_UINT16, BASE_DEC, NULL, 0x0, "" }}, { &hf_udp_checksum, { "Checksum", "udp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0, "" }}, }; static gint *ett[] = { &ett_udp, }; proto_udp = proto_register_protocol("User Datagram Protocol", "udp"); proto_register_field_array(proto_udp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); }