/* packet-udp.c * Routines for UDP packet disassembly * * $Id: packet-udp.c,v 1.75 2000/08/13 14:09:07 deniel 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 "globals.h" #include "resolv.h" #include "plugins.h" #include "packet-udp.h" #include "packet-ip.h" #include "conversation.h" #include "packet-tftp.h" #include "packet-vines.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_TFTP 69 #define UDP_PORT_VINES 573 static dissector_table_t udp_dissector_table; static heur_dissector_list_t heur_subdissector_list; /* Determine if there is a sub-dissector and call it. This has been */ /* separated into a stand alone routine to other protocol dissectors */ /* can call to it, ie. socks */ void decode_udp_ports(const u_char *pd, int offset, frame_data *fd, proto_tree *tree, int uh_sport, int uh_dport) { /* determine if this packet is part of a conversation and call dissector */ /* for the conversation if available */ if (old_try_conversation_dissector(&pi.src, &pi.dst, PT_UDP, uh_sport, uh_dport, pd, offset, fd, tree)) return; /* try to apply the plugins */ #ifdef HAVE_PLUGINS { plugin *pt_plug = plugin_list; if (enabled_plugins_number > 0) { while (pt_plug) { if (pt_plug->enabled && !strcmp(pt_plug->protocol, "udp") && tree && dfilter_apply(pt_plug->filter, tree, pd, fd->cap_len)) { pt_plug->dissector(pd, offset, fd, tree); return; } pt_plug = pt_plug->next; } } } #endif /* do lookup with the subdissector table */ if (old_dissector_try_port(udp_dissector_table, uh_sport, pd, offset, fd, tree) || old_dissector_try_port(udp_dissector_table, uh_dport, pd, offset, fd, tree)) return; /* do lookup with the heuristic subdissector table */ if (old_dissector_try_heuristic(heur_subdissector_list, pd, offset, fd, tree)) return; /* XXX - we should do these with the subdissector table as well. */ #define PORT_IS(port) (uh_sport == port || uh_dport == port) 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 */ old_dissector_add("udp.port", MAX(uh_sport, uh_dport), dissect_tftp); /* Add to table */ dissect_tftp(pd, offset, fd, tree); } else old_dissect_data(pd, offset, fd, tree); } static 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; proto_tree *udp_tree; proto_item *ti; OLD_CHECK_DISPLAY_AS_DATA(proto_udp, pd, offset, fd, tree); if (!BYTES_ARE_IN_FRAME(offset, sizeof(e_udphdr))) { old_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, NullTVB, offset, 8, FALSE); udp_tree = proto_item_add_subtree(ti, ett_udp); proto_tree_add_uint_format(udp_tree, hf_udp_srcport, NullTVB, offset, 2, uh_sport, "Source port: %s (%u)", get_udp_port(uh_sport), uh_sport); proto_tree_add_uint_format(udp_tree, hf_udp_dstport, NullTVB, offset + 2, 2, uh_dport, "Destination port: %s (%u)", get_udp_port(uh_dport), uh_dport); proto_tree_add_uint_hidden(udp_tree, hf_udp_port, NullTVB, offset, 2, uh_sport); proto_tree_add_uint_hidden(udp_tree, hf_udp_port, NullTVB, offset+2, 2, uh_dport); proto_tree_add_uint(udp_tree, hf_udp_length, NullTVB, offset + 4, 2, uh_ulen); proto_tree_add_uint_format(udp_tree, hf_udp_checksum, NullTVB, 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; /* call sub-dissectors */ decode_udp_ports( pd, offset, fd, tree, uh_sport, uh_dport); } 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)); /* subdissector code */ udp_dissector_table = register_dissector_table("udp.port"); register_heur_dissector_list("udp", &heur_subdissector_list); } void proto_reg_handoff_udp(void) { old_dissector_add("ip.proto", IP_PROTO_UDP, dissect_udp); }