/* 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 * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include /* 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: */