diff options
Diffstat (limited to 'epan/dissectors/packet-sndcp-xid.c')
| -rw-r--r-- | epan/dissectors/packet-sndcp-xid.c | 869 |
1 files changed, 869 insertions, 0 deletions
diff --git a/epan/dissectors/packet-sndcp-xid.c b/epan/dissectors/packet-sndcp-xid.c new file mode 100644 index 00000000..b5adfa3d --- /dev/null +++ b/epan/dissectors/packet-sndcp-xid.c @@ -0,0 +1,869 @@ +/* packet-sndcp-xid.c + * Routines for Subnetwork Dependent Convergence Protocol (SNDCP) XID dissection + * Used to dissect XID compression parameters negotiated in GSM (TS44.065) + * Copyright 2008, Vincent Helfre <vincent.helfre [AT] ericsson.com> + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 1998 Gerald Combs + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "config.h" + +#include <epan/packet.h> + + +/* Parameter types: TS 44.065 8 +*/ +#define SNDCP_VERSION_PAR_TYPE 0 +#define DATA_COMPRESSION_PAR_TYPE 1 +#define PROTOCOL_COMPRESSION_PAR_TYPE 2 + +/* Algorithm identifiers: TS 44.065 6.6.1.1.4 and 6.5.1.1.4 +*/ +#define ALGO_V42BIS 0 +#define ALGO_V44 1 +#define ALGO_RFC1144 0 +#define ALGO_RFC2507 1 +#define ALGO_ROHC 2 + +void proto_register_sndcp_xid(void); + +static const value_string sndcp_xid_dcomp_algo_str[] = { + {0x0, "V.42 bis"}, + {0x1, "V.44"}, + {0, NULL} +}; + +static const value_string sndcp_xid_pcomp_algo_str[] = { + {0x0, "RFC 1144"}, + {0x1, "RFC 2507"}, + {0x2, "ROHC (RFC 3095)"}, + {0, NULL} +}; + +typedef struct +{ + guint8 nb_of_dcomp_pcomp; /* note that a DCOMP or a PCOMP is 4 bit wide */ + guint16 (**func_array_ptr) (tvbuff_t *, proto_tree *, guint16); +} algo_parameters_t; + +/* Initialize the protocol and registered fields +*/ +static int proto_sndcp_xid = -1; + +/* These fields are used to store the algorithm ID +* When the P bit is not set, try to decode the algo based on what whas stored. +* Entity ranges from 0 to 31 (6.5.1.1.3) +*/ +static guint8 dcomp_entity_algo_id[32]={-1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1}; +static guint8 pcomp_entity_algo_id[32]={-1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1}; + + + +/* L3 XID parsing */ +static int hf_sndcp_xid_type = -1; +static int hf_sndcp_xid_len = -1; +static int hf_sndcp_xid_value = -1; +static int hf_sndcp_xid_comp_pbit = -1; +static int hf_sndcp_xid_comp_spare_byte1 = -1; +static int hf_sndcp_xid_comp_entity = -1; +static int hf_sndcp_xid_comp_spare_byte2 = -1; +static int hf_sndcp_xid_comp_algo_id = -1; +static int hf_sndcp_xid_comp_len = -1; +/* There is currently a maximum of 15 DCOMP/PCOMP: 6.5.1.1.5 */ +static int hf_sndcp_xid_comp[15] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}; +static int hf_sndcp_xid_comp_spare = -1; + +static int hf_element_applicable_nsapi_15 = -1; +static int hf_element_applicable_nsapi_14 = -1; +static int hf_element_applicable_nsapi_13 = -1; +static int hf_element_applicable_nsapi_12 = -1; +static int hf_element_applicable_nsapi_11 = -1; +static int hf_element_applicable_nsapi_10 = -1; +static int hf_element_applicable_nsapi_9 = -1; +static int hf_element_applicable_nsapi_8 = -1; +static int hf_element_applicable_nsapi_7 = -1; +static int hf_element_applicable_nsapi_6 = -1; +static int hf_element_applicable_nsapi_5 = -1; +static int hf_element_applicable_nsapi_spare = -1; + +static int hf_sndcp_xid_rfc1144_s0 = -1; +static int hf_sndcp_xid_rfc2507_f_max_period_msb = -1; +static int hf_sndcp_xid_rfc2507_f_max_period_lsb = -1; +static int hf_sndcp_xid_rfc2507_f_max_time = -1; +static int hf_sndcp_xid_rfc2507_max_header = -1; +static int hf_sndcp_xid_rfc2507_tcp_space = -1; +static int hf_sndcp_xid_rfc2507_non_tcp_space_msb = -1; +static int hf_sndcp_xid_rfc2507_non_tcp_space_lsb = -1; +static int hf_sndcp_xid_rohc_max_cid_spare = -1; +static int hf_sndcp_xid_rohc_max_cid_msb = -1; +static int hf_sndcp_xid_rohc_max_cid_lsb = -1; +static int hf_sndcp_xid_rohc_max_header = -1; +static int hf_sndcp_xid_rohc_profile_msb = -1; +static int hf_sndcp_xid_rohc_profile_lsb = -1; + +static int hf_sndcp_xid_V42bis_p0_spare = -1; +static int hf_sndcp_xid_V42bis_p0 = -1; +static int hf_sndcp_xid_V42bis_p1_msb = -1; +static int hf_sndcp_xid_V42bis_p1_lsb = -1; +static int hf_sndcp_xid_V42bis_p2 = -1; +static int hf_sndcp_xid_V44_c0 = -1; +static int hf_sndcp_xid_V44_c0_spare = -1; +static int hf_sndcp_xid_V44_p0_spare = -1; +static int hf_sndcp_xid_V44_p0 = -1; +static int hf_sndcp_xid_V44_p1t_msb = -1; +static int hf_sndcp_xid_V44_p1t_lsb = -1; +static int hf_sndcp_xid_V44_p1r_msb = -1; +static int hf_sndcp_xid_V44_p1r_lsb = -1; +static int hf_sndcp_xid_V44_p3t_msb = -1; +static int hf_sndcp_xid_V44_p3t_lsb = -1; +static int hf_sndcp_xid_V44_p3r_msb = -1; +static int hf_sndcp_xid_V44_p3r_lsb = -1; + + +/* Initialize the subtree pointers +*/ +static gint ett_sndcp_xid = -1; +static gint ett_sndcp_xid_version_field = -1; +static gint ett_sndcp_comp_field = -1; + +static void parse_compression_parameters(tvbuff_t *tvb, proto_tree *tree, gboolean dcomp); +/******************************************************/ +/* Compression algorithms element dissector functions */ +/******************************************************/ +static guint16 parse_applicable_nsapi(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 nsapi_byte1, nsapi_byte2; + nsapi_byte1 = tvb_get_guint8(tvb, offset); + nsapi_byte2 = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_element_applicable_nsapi_15, tvb, offset, 1, nsapi_byte1); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_14, tvb, offset, 1, nsapi_byte1); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_13, tvb, offset, 1, nsapi_byte1); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_12, tvb, offset, 1, nsapi_byte1); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_11, tvb, offset, 1, nsapi_byte1); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_10, tvb, offset, 1, nsapi_byte1); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_9, tvb, offset, 1, nsapi_byte1); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_8, tvb, offset, 1, nsapi_byte1); + + proto_tree_add_uint(tree, hf_element_applicable_nsapi_7, tvb, offset+1, 1, nsapi_byte2); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_6, tvb, offset+1, 1, nsapi_byte2); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_5, tvb, offset+1, 1, nsapi_byte2); + proto_tree_add_uint(tree, hf_element_applicable_nsapi_spare, tvb, offset+1, 1, nsapi_byte2); + + return 2U; +} + +static guint16 parse_rfc1144_s0(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 s0; + s0 = tvb_get_guint8(tvb, offset); + + proto_tree_add_uint(tree, hf_sndcp_xid_rfc1144_s0, tvb, offset, 1, s0); + + return 1U; +} + +static guint16 parse_rfc2507_f_max_period(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 f_max_period_byte1, f_max_period_byte2; + f_max_period_byte1 = tvb_get_guint8(tvb, offset); + f_max_period_byte2 = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_period_msb, tvb, offset, 1, f_max_period_byte1); + proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_period_lsb, tvb, offset, 1, f_max_period_byte2); + + return 2U; +} + +static guint16 parse_rfc2507_f_max_time(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 f_max_time; + f_max_time = tvb_get_guint8(tvb, offset); + + proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_time, tvb, offset, 1, f_max_time); + + return 1U; +} + +static guint16 parse_rfc2507_max_header(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 max_header; + max_header = tvb_get_guint8(tvb, offset); + + proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_max_header, tvb, offset, 1, max_header); + + return 1U; +} + +static guint16 parse_rfc2507_tcp_space(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 tcp_space; + tcp_space = tvb_get_guint8(tvb, offset); + + proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_tcp_space, tvb, offset, 1, tcp_space); + + return 1U; +} + +static guint16 parse_rfc2507_non_tcp_space(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 tcp_space_msb, tcp_space_lsb; + tcp_space_msb = tvb_get_guint8(tvb, offset); + tcp_space_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_non_tcp_space_msb, tvb, offset, 1, tcp_space_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_non_tcp_space_lsb, tvb, offset, 1, tcp_space_lsb); + + return 2U; +} + +static guint16 parse_rohc_max_cid(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 max_cid_msb, max_cid_lsb; + max_cid_msb = tvb_get_guint8(tvb, offset); + max_cid_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_spare, tvb, offset, 1, max_cid_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_msb, tvb, offset, 1, max_cid_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_lsb, tvb, offset+1, 1, max_cid_lsb); + + return 2U; +} +static guint16 parse_rohc_max_header(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 max_header; + + max_header = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_header, tvb, offset+1, 1, max_header); + + return 2U; +} + +static guint16 parse_rohc_profile(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 profile_msb, profile_lsb; + profile_msb = tvb_get_guint8(tvb, offset); + profile_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_rohc_profile_msb, tvb, offset, 1, profile_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_rohc_profile_lsb, tvb, offset+1, 1, profile_lsb); + + return 2U; +} + +static guint16 parse_V42bis_p0(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p0; + + p0 = tvb_get_guint8(tvb, offset); + + proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p0_spare, tvb, offset, 1, p0); + proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p0, tvb, offset, 1, p0); + + return 1U; +} + +static guint16 parse_V42bis_p1(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p1_msb, p1_lsb; + + p1_msb = tvb_get_guint8(tvb, offset); + p1_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p1_msb, tvb, offset, 1, p1_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p1_lsb, tvb, offset+1, 1, p1_lsb); + + return 2U; +} + +static guint16 parse_V42bis_p2(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p2; + + p2 = tvb_get_guint8(tvb, offset); + + proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p2, tvb, offset, 1, p2); + + return 1U; +} + +static guint16 parse_V44_c0(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 c0; + + c0 = tvb_get_guint8(tvb, offset); + proto_tree_add_uint(tree, hf_sndcp_xid_V44_c0_spare, tvb, offset, 1, c0); + proto_tree_add_uint(tree, hf_sndcp_xid_V44_c0, tvb, offset, 1, c0); + + return 1U; +} + +static guint16 parse_V44_p0(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p0; + + p0 = tvb_get_guint8(tvb, offset); + + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p0_spare, tvb, offset, 1, p0); + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p0, tvb, offset, 1, p0); + + return 1U; +} + + +static guint16 parse_V44_p1t(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p1t_msb, p1t_lsb; + + p1t_msb = tvb_get_guint8(tvb, offset); + p1t_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1t_msb, tvb, offset, 1, p1t_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1t_lsb, tvb, offset+1, 1, p1t_lsb); + + return 2U; +} + +static guint16 parse_V44_p1r(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p1r_msb, p1r_lsb; + + p1r_msb = tvb_get_guint8(tvb, offset); + p1r_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1r_msb, tvb, offset, 1, p1r_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1r_lsb, tvb, offset+1, 1, p1r_lsb); + + return 2U; +} + +static guint16 parse_V44_p3t(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p3t_msb, p3t_lsb; + + p3t_msb = tvb_get_guint8(tvb, offset); + p3t_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3t_msb, tvb, offset, 1, p3t_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3t_lsb, tvb, offset+1, 1, p3t_lsb); + + return 2U; +} + +static guint16 parse_V44_p3r(tvbuff_t *tvb, proto_tree *tree, guint16 offset) +{ + guint8 p3r_msb, p3r_lsb; + + p3r_msb = tvb_get_guint8(tvb, offset); + p3r_lsb = tvb_get_guint8(tvb, offset+1); + + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3r_msb, tvb, offset, 1, p3r_msb); + proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3r_lsb, tvb, offset+1, 1, p3r_lsb); + + return 2U; +} + + +/***************************************************/ +/* Compression algorithms element dissector arrays */ +/***************************************************/ +static guint16 (*rfc1144_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = { + parse_applicable_nsapi, + parse_rfc1144_s0, + NULL +}; + + +static guint16 (*rfc2507_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = { + parse_applicable_nsapi, + parse_rfc2507_f_max_period, + parse_rfc2507_f_max_time, + parse_rfc2507_max_header, + parse_rfc2507_tcp_space, + parse_rfc2507_non_tcp_space, + NULL +}; + +static guint16 (*rohc_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = { + parse_applicable_nsapi, + parse_rohc_max_cid, + parse_rohc_max_header, + parse_rohc_profile, /* Profile 1 */ + parse_rohc_profile, /* Profile 2 */ + parse_rohc_profile, /* Profile 3 */ + parse_rohc_profile, /* Profile 4 */ + parse_rohc_profile, /* Profile 5 */ + parse_rohc_profile, /* Profile 6 */ + parse_rohc_profile, /* Profile 7 */ + parse_rohc_profile, /* Profile 8 */ + parse_rohc_profile, /* Profile 9 */ + parse_rohc_profile, /* Profile 10 */ + parse_rohc_profile, /* Profile 11 */ + parse_rohc_profile, /* Profile 12 */ + parse_rohc_profile, /* Profile 13 */ + parse_rohc_profile, /* Profile 14 */ + parse_rohc_profile, /* Profile 15 */ + parse_rohc_profile, /* Profile 16 */ + NULL +}; + +/* Array containing the number of pcomp and the function array pointer */ +static algo_parameters_t pcomp_algo_pars[] = { + {2, rfc1144_elem_fcn}, + {5, rfc2507_elem_fcn}, + {2, rohc_elem_fcn} +}; + +/* Data compression algorithms */ + +static guint16 (*v42bis_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = { + parse_applicable_nsapi, + parse_V42bis_p0, + parse_V42bis_p1, + parse_V42bis_p2, + NULL +}; + +static guint16 (*v44_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = { + parse_applicable_nsapi, + parse_V44_c0, + parse_V44_p0, + parse_V44_p1t, + parse_V44_p1r, + parse_V44_p3t, + parse_V44_p3r, + NULL +}; + +/* Array containing the number of dcomp and the function array pointer */ +static algo_parameters_t dcomp_algo_pars[] = { + {1, v42bis_elem_fcn}, + {2, v44_elem_fcn}, + +}; + +/* Code to actually dissect the packets +*/ +static int +dissect_sndcp_xid(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, void* data _U_) +{ + /* Set up structures needed to add the protocol subtree and manage it + */ + proto_item *ti, *dcomp_item; + proto_tree *sndcp_tree, *version_tree, *dcomp_tree, *pcomp_tree; + guint16 offset = 0, l3_param_len; + guint8 parameter_type, parameter_len; + + /* create display subtree for the protocol + */ + ti = proto_tree_add_item(tree, proto_sndcp_xid, tvb, 0, -1, ENC_NA); + sndcp_tree = proto_item_add_subtree(ti, ett_sndcp_xid); + l3_param_len = tvb_reported_length(tvb); + + while (offset < l3_param_len-1) + { + parameter_type = tvb_get_guint8(tvb, offset); + parameter_len = tvb_get_guint8(tvb, offset+1); + + if (parameter_type == SNDCP_VERSION_PAR_TYPE) + { + guint8 value = tvb_get_guint8(tvb, offset+2); + version_tree = proto_tree_add_subtree_format(sndcp_tree, tvb, offset, parameter_len+2, + ett_sndcp_xid_version_field, NULL, "Version (SNDCP version number) - Value %d", value); + + proto_tree_add_uint(version_tree, hf_sndcp_xid_type, tvb, offset, + 1, parameter_type); + proto_tree_add_uint(version_tree, hf_sndcp_xid_len, tvb, offset+1, + 1, parameter_len); + proto_tree_add_uint(version_tree, hf_sndcp_xid_value, tvb, offset+2, + 1, value); + offset += 3; + } + + else if (parameter_type == DATA_COMPRESSION_PAR_TYPE) + { + tvbuff_t * dcomp_tvb; + + dcomp_tree = proto_tree_add_subtree(sndcp_tree, tvb, offset, parameter_len+2, + ett_sndcp_comp_field, &dcomp_item, "Data Compression"); + proto_tree_add_uint(dcomp_tree, hf_sndcp_xid_type, tvb, offset, + 1, parameter_type); + proto_tree_add_uint(dcomp_tree, hf_sndcp_xid_len, tvb, offset+1, + 1, parameter_len); + offset += 2; + + dcomp_tvb = tvb_new_subset_length(tvb, offset, parameter_len); + parse_compression_parameters(dcomp_tvb, dcomp_tree, TRUE); + offset += parameter_len; + + + } + else if (parameter_type == PROTOCOL_COMPRESSION_PAR_TYPE) + { + tvbuff_t * pcomp_tvb; + + pcomp_tree = proto_tree_add_subtree(sndcp_tree, tvb, offset, parameter_len+2, + ett_sndcp_comp_field, NULL, "Protocol Control Information Compression"); + proto_tree_add_uint(pcomp_tree, hf_sndcp_xid_type, tvb, offset, + 1, parameter_type); + proto_tree_add_uint(pcomp_tree, hf_sndcp_xid_len, tvb, offset+1, + 1, parameter_len); + offset += 2; + + pcomp_tvb = tvb_new_subset_length(tvb, offset, parameter_len); + parse_compression_parameters(pcomp_tvb, pcomp_tree, FALSE); + offset += parameter_len; + + } + else + { + break; /* error: exit */ + } + } + return tvb_captured_length(tvb); +} + + +static void parse_compression_parameters(tvbuff_t *tvb, proto_tree *tree, gboolean dcomp) +{ + guint8 entity, len, algo_id; + guint8 number_of_comp, i; + gboolean p_bit_set; + algo_parameters_t * algo_pars; + guint8 function_index; + proto_tree *comp_entity_tree = NULL; + guint16 tvb_len, offset=0 , new_offset, entity_offset; + value_string const * comp_algo_str; + + tvb_len = tvb_reported_length(tvb); + if (tvb_len < 3) return; /* entity, algo and length bytes should always be present 6.5.1.1 and 6.6.1.1 */ + + /* Loop to decode each entity (cf Figure 10) */ + while (offset < tvb_len) + { + /* Read the entity byte */ + entity = tvb_get_guint8(tvb, offset); + p_bit_set = ((entity & 0x80) == 0x80) ? 1 : 0; + entity = entity & 0x1F; + + /* P bit is set: means that algo identifier and dcomp are present */ + if (p_bit_set) + { + /* Read the algorithm id. TODO: store the algo in a different variable for each different entity */ + algo_id = tvb_get_guint8(tvb, offset+1) & 0x1F; + + /* sanity check: check that the algo id that will be used inside the array has a valid range */ + if (dcomp) + { + if(algo_id <= ALGO_V44) + { + algo_pars = dcomp_algo_pars; + dcomp_entity_algo_id[entity] = algo_id; + comp_algo_str = sndcp_xid_dcomp_algo_str; + } + else return; + } + else + { + if (algo_id <= ALGO_ROHC) + { + algo_pars = pcomp_algo_pars; + pcomp_entity_algo_id[entity] = algo_id; + comp_algo_str = sndcp_xid_pcomp_algo_str; + } + else return; + } + + /* Read the length */ + len = tvb_get_guint8(tvb, offset+2); + + comp_entity_tree = proto_tree_add_subtree_format(tree, tvb, offset, len + 3, + ett_sndcp_comp_field, NULL, "Entity %d, Algorithm %s", + entity & 0x1F, val_to_str(algo_id & 0x1F, comp_algo_str,"Undefined Algorithm Identifier:%X")); + + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_pbit, tvb, offset, 1, p_bit_set << 7); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte1, tvb, offset, 1, entity); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_entity, tvb, offset, 1, entity); + + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte2, tvb, offset+1, 1, algo_id); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_algo_id, tvb, offset+1, 1, algo_id); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_len, tvb, offset+2, 1, len); + + /* Read the dcomp/pcomp field */ + offset += 3; /* entity_offset will be used as the offset from length byte */ + number_of_comp = algo_pars[algo_id].nb_of_dcomp_pcomp; + + for (i=0; i < (number_of_comp+1) / 2; i++) + { + guint8 byte; + + byte = tvb_get_guint8(tvb, offset+i); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp[2*i], tvb, offset+i, 1, byte); + + /* if there is an even number of dcomp/pcomp */ + if (2*i+1 < number_of_comp) + { + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp[2*i+1], tvb, offset+i, 1, byte); + } + /* else there is padding in the end */ + else + { + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare, tvb, offset+i, 1, byte); + } + + } + entity_offset = i; + function_index = 0; + + /* Process the elements byte per byte */ + while ((entity_offset < len) && (algo_pars[algo_id].func_array_ptr[function_index] != NULL)) + { + new_offset = offset+entity_offset; + entity_offset += algo_pars[algo_id].func_array_ptr[function_index](tvb, comp_entity_tree, new_offset); + function_index++; + } + offset += entity_offset; + + } + else /* P bit not set */ + { + len = tvb_get_guint8(tvb, offset+1); + + if (dcomp) + { + algo_pars = dcomp_algo_pars; + algo_id = dcomp_entity_algo_id[entity]; + comp_algo_str = sndcp_xid_dcomp_algo_str; + } + else + { + algo_pars = pcomp_algo_pars; + algo_id = pcomp_entity_algo_id[entity]; + comp_algo_str = sndcp_xid_pcomp_algo_str; + } + comp_entity_tree = proto_tree_add_subtree_format(tree, tvb, offset, len + 2, + ett_sndcp_comp_field, NULL, "Entity %d decoded as Algorithm %s", + entity & 0x1F, val_to_str(algo_id & 0x1F, comp_algo_str,"Undefined Algorithm Identifier:%X")); + + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_pbit, tvb, offset, 1, p_bit_set << 7); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte1, tvb, offset, 1, entity); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_entity, tvb, offset, 1, entity); + proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_len, tvb, offset+2, 1, len); + + offset += 2; + entity_offset = 0; + function_index = 0; + + if (dcomp) + { + if (algo_id > ALGO_V44) return; + } + else + { + if (algo_id > ALGO_ROHC) return; + } + + /* Process the elements byte per byte */ + while ((entity_offset < len) && (algo_pars[algo_id].func_array_ptr[function_index] != NULL)) + { + new_offset = offset+entity_offset; + entity_offset += algo_pars[algo_id].func_array_ptr[function_index](tvb, comp_entity_tree, new_offset); + function_index++; + } + offset += entity_offset; + } + } + + /* Else if length is lower than 3, the packet is not correctly formatted */ +} + +/* Register the protocol with Wireshark + this format is required because a script is used to build the C function + that calls all the protocol registration. +*/ + +void +proto_register_sndcp_xid(void) +{ + /* Setup list of header fields + */ + static hf_register_info hf[] = { + /* L3 XID Parameter Parsing Info */ + {&hf_sndcp_xid_type, + { "Parameter type","llcgprs.l3xidpartype", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_len, + { "Length","llcgprs.l3xidparlen", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_value, + { "Value","llcgprs.l3xidparvalue", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_comp_pbit, + { "P bit","llcgprs.l3xiddcomppbit", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}}, + {&hf_sndcp_xid_comp_spare_byte1, + { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0x60, "Ignore", HFILL}}, + {&hf_sndcp_xid_comp_entity, + { "Entity","llcgprs.l3xidentity", FT_UINT8, BASE_DEC, NULL, 0x1F, "Data", HFILL}}, + {&hf_sndcp_xid_comp_spare_byte2, + { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0xE0, "Ignore", HFILL}}, + {&hf_sndcp_xid_comp_algo_id, + { "Algorithm identifier","llcgprs.l3xidalgoid", FT_UINT8, BASE_DEC, NULL, 0x1F, "Data", HFILL}}, + {&hf_sndcp_xid_comp_len, + { "Length","llcgprs.l3xidcomplen", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[0], + { "DCOMP1","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[1], + { "DCOMP2","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}}, + {&hf_sndcp_xid_comp[2], + { "DCOMP3","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[3], + { "DCOMP4","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}}, + {&hf_sndcp_xid_comp[4], + { "DCOMP5","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[5], + { "DCOMP6","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}}, + {&hf_sndcp_xid_comp[6], + { "DCOMP7","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[7], + { "DCOMP8","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}}, + {&hf_sndcp_xid_comp[8], + { "DCOMP9","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[9], + { "DCOMP10","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}}, + {&hf_sndcp_xid_comp[10], + { "DCOMP11","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[11], + { "DCOMP12","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}}, + {&hf_sndcp_xid_comp[12], + { "DCOMP13","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp[13], + { "DCOMP14","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}}, + {&hf_sndcp_xid_comp[14], + { "DCOMP15","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}}, + {&hf_sndcp_xid_comp_spare, + { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0x0F, "Ignore", HFILL}}, + {&hf_element_applicable_nsapi_15, + { "NSAPI 15","sndcpxid.nsapi15", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}}, + {&hf_element_applicable_nsapi_14, + { "NSAPI 14","sndcpxid.nsapi14", FT_UINT8, BASE_DEC, NULL, 0x40, "Data", HFILL}}, + {&hf_element_applicable_nsapi_13, + { "NSAPI 13","sndcpxid.nsapi13", FT_UINT8, BASE_DEC, NULL, 0x20, "Data", HFILL}}, + {&hf_element_applicable_nsapi_12, + { "NSAPI 12","sndcpxid.nsapi12", FT_UINT8, BASE_DEC, NULL, 0x10, "Data", HFILL}}, + {&hf_element_applicable_nsapi_11, + { "NSAPI 11","sndcpxid.nsapi11", FT_UINT8, BASE_DEC, NULL, 0x08, "Data", HFILL}}, + {&hf_element_applicable_nsapi_10, + { "NSAPI 10","sndcpxid.nsapi10", FT_UINT8, BASE_DEC, NULL, 0x04, "Data", HFILL}}, + {&hf_element_applicable_nsapi_9, + { "NSAPI 9","sndcpxid.nsapi9", FT_UINT8, BASE_DEC, NULL, 0x02, "Data", HFILL}}, + {&hf_element_applicable_nsapi_8, + { "NSAPI 8","sndcpxid.nsapi8", FT_UINT8, BASE_DEC, NULL, 0x01, "Data", HFILL}}, + {&hf_element_applicable_nsapi_7, + { "NSAPI 7","sndcpxid.nsapi7", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}}, + {&hf_element_applicable_nsapi_6, + { "NSAPI 6","sndcpxid.nsapi6", FT_UINT8, BASE_DEC, NULL, 0x40, "Data", HFILL}}, + {&hf_element_applicable_nsapi_5, + { "NSAPI 5","sndcpxid.nsapi5", FT_UINT8, BASE_DEC, NULL, 0x20, "Data", HFILL}}, + {&hf_element_applicable_nsapi_spare, + { "Spare","sndcpxid.spare", FT_UINT8, BASE_DEC, NULL, 0x1F, "Ignore", HFILL}}, + {&hf_sndcp_xid_rfc1144_s0, + { "S0 - 1","sndcpxid.rfc1144_s0", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rfc2507_f_max_period_msb, + { "F Max Period MSB","sndcpxid.rfc2507_f_max_period_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rfc2507_f_max_period_lsb, + { "F Max Period LSB","sndcpxid.rfc2507_f_max_period_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rfc2507_f_max_time, + { "F Max Time","sndcpxid.rfc2507_f_max_time", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rfc2507_max_header, + { "Max Header","sndcpxid.rfc2507_max_header", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rfc2507_tcp_space, + { "TCP Space","sndcpxid.rfc2507_max_tcp_space", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rfc2507_non_tcp_space_msb, + { "TCP non space MSB","sndcpxid.rfc2507_max_non_tcp_space_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rfc2507_non_tcp_space_lsb, + { "TCP non space LSB","sndcpxid.rfc2507_max_non_tcp_space_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rohc_max_cid_spare, + { "Spare","sndcpxid.rohc_max_cid_spare", FT_UINT8, BASE_DEC, NULL, 0xC0, "Ignore", HFILL}}, + {&hf_sndcp_xid_rohc_max_cid_msb, + { "Max CID MSB","sndcpxid.rohc_max_cid_msb", FT_UINT8, BASE_HEX, NULL, 0x3F, "Data", HFILL}}, + {&hf_sndcp_xid_rohc_max_cid_lsb, + { "Max CID LSB","sndcpxid.rohc_max_cid_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rohc_max_header, + { "Max header","sndcpxid.rohc_max_header", FT_UINT8, BASE_DEC, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rohc_profile_msb, + { "Profile MSB","sndcpxid.rohc_profile_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_rohc_profile_lsb, + { "Profile LSB","sndcpxid.rohc_profile_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V42bis_p0_spare, + { "Spare","sndcpxid.V42bis_p0spare", FT_UINT8, BASE_DEC, NULL, 0xFC, "Ignore", HFILL}}, + {&hf_sndcp_xid_V42bis_p0, + { "P0","sndcpxid.V42bis_p0", FT_UINT8, BASE_HEX, NULL, 0x03, "Data", HFILL}}, + {&hf_sndcp_xid_V42bis_p1_msb, + { "P1 MSB","sndcpxid.V42bis_p1_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V42bis_p1_lsb, + { "P1 LSB","sndcpxid.V42bis_p1_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V42bis_p2, + { "P2","sndcpxid.V42bis_p2", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_c0_spare, + { "P2","sndcpxid.V44_c0_spare", FT_UINT8, BASE_HEX, NULL, 0x3F, "Ignore", HFILL}}, + {&hf_sndcp_xid_V44_c0, + { "P2","sndcpxid.V44_c0", FT_UINT8, BASE_HEX, NULL, 0xC0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p0_spare, + { "Spare","sndcpxid.V44_p0spare", FT_UINT8, BASE_DEC, NULL, 0xFC, "Ignore", HFILL}}, + {&hf_sndcp_xid_V44_p0, + { "P0","sndcpxid.V44_p0", FT_UINT8, BASE_HEX, NULL, 0x03, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p1t_msb, + { "P1t MSB","sndcpxid.V44_p1t_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p1t_lsb, + { "P1t LSB","sndcpxid.V44_p1t_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p1r_msb, + { "P1r MSB","sndcpxid.V44_p1r_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p1r_lsb, + { "P1r LSB","sndcpxid.V44_p1r_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p3t_msb, + { "P3t MSB","sndcpxid.V44_p3t_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p3t_lsb, + { "P3t LSB","sndcpxid.V44_p3t_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p3r_msb, + { "P3r MSB","sndcpxid.V44_p3r_msb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + {&hf_sndcp_xid_V44_p3r_lsb, + { "P3r LSB","sndcpxid.V44_p3r_lsb", FT_UINT8, BASE_HEX, NULL, 0x0, "Data", HFILL}}, + }; + + /* Setup protocol subtree array */ + static gint *ett[] = { + &ett_sndcp_xid, + &ett_sndcp_xid_version_field, + &ett_sndcp_comp_field + }; + + /* Register the protocol name and description */ + proto_sndcp_xid = proto_register_protocol("Subnetwork Dependent Convergence Protocol XID", + "SNDCP XID", "sndcpxid"); + + /* Required function calls to register the header fields and subtrees used */ + proto_register_field_array(proto_sndcp_xid, hf, array_length(hf)); + proto_register_subtree_array(ett, array_length(ett)); + register_dissector("sndcpxid", dissect_sndcp_xid, proto_sndcp_xid); +} + +/* + * Editor modelines - https://www.wireshark.org/tools/modelines.html + * + * Local variables: + * c-basic-offset: 4 + * tab-width: 8 + * indent-tabs-mode: nil + * End: + * + * vi: set shiftwidth=4 tabstop=8 expandtab: + * :indentSize=4:tabSize=8:noTabs=true: + */ |