forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
This emphasizes that there is no such thing as *the* routine to construct a subset tvbuff; you need to choose one of tvb_new_subset_remaining() (if you want a new tvbuff that contains everything past a certain point in an existing tvbuff), tvb_new_subset_length() (if you want a subset that contains everything past a certain point, for some number of bytes, in an existing tvbuff), and tvb_new_subset_length_caplen() (for all other cases). Many of the calls to tvb_new_subset_length_caplen() should really be calling one of the other routines; that's the next step. (This also makes it easier to find the calls that need fixing.) Change-Id: Ieb3d676d8cda535451c119487d7cd3b559221f2b Reviewed-on: https://code.wireshark.org/review/19597 Reviewed-by: Guy Harris <guy@alum.mit.edu>
415 lines
12 KiB
C
415 lines
12 KiB
C
/* packet-xip-serval.c
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* Routines for XIP Serval dissection
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Serval is a service-centric architecture that has been ported to XIA to
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* allow applications to communicate using service names.
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/expert.h>
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#include <epan/in_cksum.h>
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#include <ipproto.h>
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void proto_register_xip_serval(void);
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void proto_reg_handoff_xip_serval(void);
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static dissector_handle_t tcp_handle;
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static dissector_handle_t udp_handle;
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static gint proto_xip_serval = -1;
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/* XIP Serval header. */
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static gint hf_xip_serval_hl = -1;
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static gint hf_xip_serval_proto = -1;
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static gint hf_xip_serval_check = -1;
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static gint hf_xip_serval_check_status = -1;
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/* XIP Serval general extension header. */
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static gint hf_xip_serval_ext_type = -1;
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static gint hf_xip_serval_ext_length = -1;
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/* XIP Serval control extension header. */
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static gint hf_xip_serval_cext = -1;
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static gint hf_xip_serval_cext_flags = -1;
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static gint hf_xip_serval_cext_syn = -1;
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static gint hf_xip_serval_cext_rsyn = -1;
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static gint hf_xip_serval_cext_ack = -1;
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static gint hf_xip_serval_cext_nack = -1;
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static gint hf_xip_serval_cext_rst = -1;
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static gint hf_xip_serval_cext_fin = -1;
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static gint hf_xip_serval_cext_verno = -1;
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static gint hf_xip_serval_cext_ackno = -1;
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static gint hf_xip_serval_cext_nonce = -1;
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static gint ett_xip_serval_tree = -1;
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static gint ett_xip_serval_cext = -1;
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static gint ett_xip_serval_cext_flags = -1;
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static expert_field ei_xip_serval_bad_len = EI_INIT;
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static expert_field ei_xip_serval_bad_proto = EI_INIT;
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static expert_field ei_xip_serval_bad_checksum = EI_INIT;
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static expert_field ei_xip_serval_bad_ext = EI_INIT;
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#define XIP_SERVAL_PROTO_DATA 0
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static const value_string xip_serval_proto_vals[] = {
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{ XIP_SERVAL_PROTO_DATA, "Data" },
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{ IP_PROTO_TCP, "TCP" },
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{ IP_PROTO_UDP, "UDP" },
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{ 0, NULL },
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};
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static const gint *xip_serval_cext_flags[] = {
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&hf_xip_serval_cext_syn,
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&hf_xip_serval_cext_rsyn,
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&hf_xip_serval_cext_ack,
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&hf_xip_serval_cext_nack,
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&hf_xip_serval_cext_rst,
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&hf_xip_serval_cext_fin,
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NULL
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};
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#define XIP_SERVAL_MIN_LEN 4
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#define XIP_SERVAL_EXT_MIN_LEN 2
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#define XIP_SERVAL_EXT_TYPE_MASK 0xF0
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#define XIP_SERVAL_EXT_TYPE_CONTROL 0
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#define XIP_SERVAL_CEXT_FLAGS_WIDTH 8
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#define XIP_SERVAL_CEXT_NONCE_SIZE 8
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#define XIP_SERVAL_CEXT_LEN 20
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#define XSRVL_LEN 0
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#define XSRVL_PRO 1
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#define XSRVL_CHK 2
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#define XSRVL_EXT 4
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static guint8
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display_xip_serval_control_ext(tvbuff_t *tvb, proto_tree *xip_serval_tree,
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gint offset, guint8 type, guint8 length)
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{
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proto_tree *cext_tree;
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proto_item *ti;
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/* Create Serval Control Extension tree. */
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ti = proto_tree_add_item(xip_serval_tree, hf_xip_serval_cext, tvb,
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offset, length, ENC_NA);
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cext_tree = proto_item_add_subtree(ti, ett_xip_serval_cext);
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/* Add XIP Serval extension type. */
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proto_tree_add_uint(cext_tree, hf_xip_serval_ext_type, tvb,
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offset, 1, type);
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offset++;
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/* Add XIP Serval extension length. */
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proto_tree_add_item(cext_tree, hf_xip_serval_ext_length, tvb,
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offset, 1, ENC_BIG_ENDIAN);
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offset++;
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/* Create XIP Serval Control Extension flags tree. */
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proto_tree_add_bitmask(cext_tree, tvb, offset,
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hf_xip_serval_cext_flags, ett_xip_serval_cext_flags,
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xip_serval_cext_flags, ENC_BIG_ENDIAN);
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/* Skip two bits for res1. */
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offset++;
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/* Skip a byte for res2. */
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offset++;
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/* Add verification number. */
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proto_tree_add_item(cext_tree, hf_xip_serval_cext_verno,
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tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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/* Add acknowledgement number. */
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proto_tree_add_item(cext_tree, hf_xip_serval_cext_ackno,
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tvb, offset, 4, ENC_BIG_ENDIAN);
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offset += 4;
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/* Add nonce. */
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proto_tree_add_item(cext_tree, hf_xip_serval_cext_nonce,
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tvb, offset, 8, ENC_NA);
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/* Displayed XIP_SERVAL_CEXT_LEN bytes. */
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return XIP_SERVAL_CEXT_LEN;
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}
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static guint8
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display_xip_serval_ext(tvbuff_t *tvb, packet_info *pinfo, proto_item *ti,
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proto_tree *xip_serval_tree, gint offset)
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{
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guint8 type = tvb_get_guint8(tvb, offset) & XIP_SERVAL_EXT_TYPE_MASK;
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guint8 length = tvb_get_guint8(tvb, offset + 1);
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/* For now, the only type of extension header in XIP Serval is
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* the control extension header.
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*/
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switch (type) {
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case XIP_SERVAL_EXT_TYPE_CONTROL:
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return display_xip_serval_control_ext(tvb, xip_serval_tree,
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offset, type, length);
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default:
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expert_add_info_format(pinfo, ti, &ei_xip_serval_bad_ext,
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"Unrecognized Serval extension header type: 0x%02x",
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type);
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return 0;
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}
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}
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static void
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display_xip_serval(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *xip_serval_tree;
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proto_item *ti, *hl_ti;
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tvbuff_t *next_tvb;
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vec_t cksum_vec;
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gint offset;
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guint8 xsh_len, protocol, bytes_remaining;
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/* Get XIP Serval header length, stored as number of 32-bit words. */
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xsh_len = tvb_get_guint8(tvb, XSRVL_LEN) << 2;
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/* Create XIP Serval header tree. */
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ti = proto_tree_add_item(tree, proto_xip_serval, tvb,
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0, xsh_len, ENC_NA);
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xip_serval_tree = proto_item_add_subtree(ti, ett_xip_serval_tree);
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/* Add XIP Serval header length. */
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hl_ti = proto_tree_add_item(xip_serval_tree, hf_xip_serval_hl, tvb,
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XSRVL_LEN, 1, ENC_BIG_ENDIAN);
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if (tvb_captured_length(tvb) < xsh_len)
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expert_add_info_format(pinfo, hl_ti, &ei_xip_serval_bad_len,
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"Header Length field (%d bytes) cannot be greater than actual number of bytes left in packet (%d bytes)",
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xsh_len, tvb_captured_length(tvb));
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/* Add XIP Serval protocol. If it's not data, TCP, or UDP, the
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* packet is malformed.
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*/
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proto_tree_add_item(xip_serval_tree, hf_xip_serval_proto, tvb,
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XSRVL_PRO, 1, ENC_BIG_ENDIAN);
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protocol = tvb_get_guint8(tvb, XSRVL_PRO);
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if (!try_val_to_str(protocol, xip_serval_proto_vals))
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expert_add_info_format(pinfo, ti, &ei_xip_serval_bad_proto,
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"Unrecognized protocol type: %d", protocol);
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/* Compute checksum. */
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SET_CKSUM_VEC_TVB(cksum_vec, tvb, 0, xsh_len);
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proto_tree_add_checksum(xip_serval_tree, tvb, XSRVL_CHK, hf_xip_serval_check, hf_xip_serval_check_status, &ei_xip_serval_bad_checksum, pinfo, in_cksum(&cksum_vec, 1),
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ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_IN_CKSUM);
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offset = XSRVL_EXT;
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/* If there's still more room, check for extension headers. */
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bytes_remaining = xsh_len - offset;
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while (bytes_remaining >= XIP_SERVAL_EXT_MIN_LEN) {
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gint8 bytes_displayed = display_xip_serval_ext(tvb, pinfo, ti,
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xip_serval_tree, offset);
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/* Extension headers are malformed, so we can't say
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* what the rest of the packet holds. Stop dissecting.
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*/
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if (bytes_displayed <= 0)
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return;
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offset += bytes_displayed;
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bytes_remaining -= bytes_displayed;
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}
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switch (protocol) {
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case XIP_SERVAL_PROTO_DATA:
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next_tvb = tvb_new_subset_remaining(tvb, offset);
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call_data_dissector(next_tvb, pinfo, tree);
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break;
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case IP_PROTO_TCP: {
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/* Get the Data Offset field of the TCP header, which is
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* the high nibble of the 12th octet and represents the
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* size of the TCP header of 32-bit words.
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*/
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guint8 tcp_len = hi_nibble(tvb_get_guint8(tvb, offset + 12))*4;
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next_tvb = tvb_new_subset_length_caplen(tvb, offset, tcp_len, tcp_len);
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call_dissector(tcp_handle, next_tvb, pinfo, tree);
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break;
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}
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case IP_PROTO_UDP:
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/* The UDP header is always 8 bytes. */
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next_tvb = tvb_new_subset_length_caplen(tvb, offset, 8, 8);
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call_dissector(udp_handle, next_tvb, pinfo, tree);
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break;
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default:
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break;
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}
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}
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static gint
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dissect_xip_serval(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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void *data _U_)
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{
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if (tvb_reported_length(tvb) < XIP_SERVAL_MIN_LEN)
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return 0;
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col_append_str(pinfo->cinfo, COL_INFO, " (with Serval)");
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display_xip_serval(tvb, pinfo, tree);
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return tvb_captured_length(tvb);
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}
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void
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proto_register_xip_serval(void)
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{
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static hf_register_info hf[] = {
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/* Serval Header. */
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{ &hf_xip_serval_hl,
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{ "Header Length", "xip_serval.hl", FT_UINT8,
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BASE_DEC|BASE_UNIT_STRING, &units_byte_bytes, 0x0, NULL, HFILL }},
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{ &hf_xip_serval_proto,
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{ "Protocol", "xip_serval.proto", FT_UINT8,
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BASE_DEC, VALS(xip_serval_proto_vals), 0x0, NULL, HFILL }},
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{ &hf_xip_serval_check,
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{ "Checksum", "xip_serval.check", FT_UINT16,
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BASE_HEX, NULL, 0x0, NULL, HFILL }},
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{ &hf_xip_serval_check_status,
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{ "Checksum Status", "xip_serval.check.status", FT_UINT8,
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BASE_NONE, VALS(proto_checksum_vals), 0x0, NULL, HFILL }},
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/* Serval Extension Header. */
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{ &hf_xip_serval_ext_type,
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{ "Extension Type", "xip_serval.ext_type", FT_UINT8,
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BASE_DEC, NULL, 0x0, NULL, HFILL }},
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{ &hf_xip_serval_ext_length,
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{ "Extension Length", "xip_serval.ext_length", FT_UINT8,
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BASE_DEC|BASE_UNIT_STRING, &units_byte_bytes, 0x0, NULL, HFILL }},
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/* Serval Control Extension Header. */
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{ &hf_xip_serval_cext,
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{ "Serval Control Extension", "xip_serval.cext",
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FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL }},
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{ &hf_xip_serval_cext_flags,
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{ "Flags", "xip_serval.cext_flags", FT_UINT8, BASE_HEX,
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NULL, 0x0, NULL, HFILL }},
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{ &hf_xip_serval_cext_syn,
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{ "SYN", "xip_serval.cext_syn", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), 0x80, NULL, HFILL }},
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{ &hf_xip_serval_cext_rsyn,
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{ "RSYN", "xip_serval.cext_rsyn", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), 0x40, NULL, HFILL }},
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{ &hf_xip_serval_cext_ack,
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{ "ACK", "xip_serval.cext_ack", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), 0x20, NULL, HFILL }},
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{ &hf_xip_serval_cext_nack,
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{ "NACK", "xip_serval.cext_nack", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), 0x10, NULL, HFILL }},
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{ &hf_xip_serval_cext_rst,
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{ "RST", "xip_serval.cext_rst", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), 0x08, NULL, HFILL }},
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{ &hf_xip_serval_cext_fin,
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{ "FIN", "xip_serval.cext_fin", FT_BOOLEAN, 8,
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TFS(&tfs_set_notset), 0x04, NULL, HFILL }},
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{ &hf_xip_serval_cext_verno,
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{ "Version Number", "xip_serval.cext_verno", FT_UINT32,
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BASE_DEC, NULL, 0x0, NULL, HFILL }},
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{ &hf_xip_serval_cext_ackno,
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{ "Acknowledgement Number", "xip_serval.cext_ackno",
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FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL }},
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{ &hf_xip_serval_cext_nonce,
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{ "Nonce", "xip_serval.cext_nonce", FT_BYTES,
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SEP_SPACE, NULL, 0x0, NULL, HFILL }}
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};
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static gint *ett[] = {
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&ett_xip_serval_tree,
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&ett_xip_serval_cext,
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&ett_xip_serval_cext_flags
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};
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static ei_register_info ei[] = {
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{ &ei_xip_serval_bad_len,
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{ "xip_serval.bad_len", PI_MALFORMED, PI_ERROR,
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"Bad header length", EXPFILL }},
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{ &ei_xip_serval_bad_ext,
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{ "xip_serval.bad_ext", PI_MALFORMED, PI_ERROR,
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"Bad extension header type", EXPFILL }},
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{ &ei_xip_serval_bad_proto,
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{ "xip_serval.bad_proto", PI_MALFORMED, PI_ERROR,
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"Bad protocol type", EXPFILL }},
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{ &ei_xip_serval_bad_checksum,
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{ "xip_serval.bad_checksum", PI_MALFORMED, PI_ERROR,
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"Incorrect checksum", EXPFILL }}
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};
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expert_module_t* expert_xip_serval;
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proto_xip_serval = proto_register_protocol(
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"XIP Serval",
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"XIP Serval",
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"xipserval");
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register_dissector("xipserval", dissect_xip_serval,
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proto_xip_serval);
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proto_register_field_array(proto_xip_serval, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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expert_xip_serval = expert_register_protocol(proto_xip_serval);
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expert_register_field_array(expert_xip_serval, ei, array_length(ei));
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}
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void
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proto_reg_handoff_xip_serval(void)
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{
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tcp_handle = find_dissector_add_dependency("tcp", proto_xip_serval);
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udp_handle = find_dissector_add_dependency("udp", proto_xip_serval);
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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