From f1f34360fb4680adc25a7e8b4b31062ba606e8dc Mon Sep 17 00:00:00 2001 From: Philipp Date: Fri, 26 Aug 2016 17:00:21 +0200 Subject: SNDCP: add RFC1144 header compression functionality - Add module to handle compression entities - Add module to control header compression - Introduce VTY commands for heade compression configuration - Add changes in sndcp and llc to integrate header compression Change-Id: Ia00260dc09978844c2865957b4d43000b78b5e43 --- openbsc/src/gprs/gprs_sndcp.c | 610 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 593 insertions(+), 17 deletions(-) (limited to 'openbsc/src/gprs/gprs_sndcp.c') diff --git a/openbsc/src/gprs/gprs_sndcp.c b/openbsc/src/gprs/gprs_sndcp.c index 4f711212a..c006d9bcf 100644 --- a/openbsc/src/gprs/gprs_sndcp.c +++ b/openbsc/src/gprs/gprs_sndcp.c @@ -35,6 +35,131 @@ #include #include #include +#include +#include +#include +#include + +#define DEBUG_IP_PACKETS 0 /* 0=Disabled, 1=Enabled */ + +#if DEBUG_IP_PACKETS == 1 +/* Calculate TCP/IP checksum */ +static uint16_t calc_ip_csum(uint8_t *data, int len) +{ + int i; + uint32_t accumulator = 0; + uint16_t *pointer = (uint16_t *) data; + + for (i = len; i > 1; i -= 2) { + accumulator += *pointer; + pointer++; + } + + if (len % 2) + accumulator += *pointer; + + accumulator = (accumulator & 0xffff) + ((accumulator >> 16) & 0xffff); + accumulator += (accumulator >> 16) & 0xffff; + return (~accumulator); +} + +/* Calculate TCP/IP checksum */ +static uint16_t calc_tcpip_csum(const void *ctx, uint8_t *packet, int len) +{ + uint8_t *buf; + uint16_t csum; + + buf = talloc_zero_size(ctx, len); + memset(buf, 0, len); + memcpy(buf, packet + 12, 8); + buf[9] = packet[9]; + buf[11] = (len - 20) & 0xFF; + buf[10] = (len - 20) >> 8 & 0xFF; + memcpy(buf + 12, packet + 20, len - 20); + csum = calc_ip_csum(buf, len - 20 + 12); + talloc_free(buf); + return csum; +} + +/* Show some ip packet details */ +static void debug_ip_packet(uint8_t *data, int len, int dir, char *info) +{ + uint8_t tcp_flags; + char flags_debugmsg[256]; + int len_short; + static unsigned int packet_count = 0; + static unsigned int tcp_csum_err_count = 0; + static unsigned int ip_csum_err_count = 0; + + packet_count++; + + if (len > 80) + len_short = 80; + else + len_short = len; + + if (dir) + DEBUGP(DSNDCP, "%s: MS => SGSN: %s\n", info, + osmo_hexdump_nospc(data, len_short)); + else + DEBUGP(DSNDCP, "%s: MS <= SGSN: %s\n", info, + osmo_hexdump_nospc(data, len_short)); + + DEBUGP(DSNDCP, "%s: Length.: %d\n", info, len); + DEBUGP(DSNDCP, "%s: NO.: %d\n", info, packet_count); + + if (len < 20) { + DEBUGP(DSNDCP, "%s: Error: Short IP packet!\n", info); + return; + } + + if (calc_ip_csum(data, 20) != 0) { + DEBUGP(DSNDCP, "%s: Bad IP-Header checksum!\n", info); + ip_csum_err_count++; + } else + DEBUGP(DSNDCP, "%s: IP-Header checksum ok.\n", info); + + if (data[9] == 0x06) { + if (len < 40) { + DEBUGP(DSNDCP, "%s: Error: Short TCP packet!\n", info); + return; + } + + DEBUGP(DSNDCP, "%s: Protocol type: TCP\n", info); + tcp_flags = data[33]; + + if (calc_tcpip_csum(NULL, data, len) != 0) { + DEBUGP(DSNDCP, "%s: Bad TCP checksum!\n", info); + tcp_csum_err_count++; + } else + DEBUGP(DSNDCP, "%s: TCP checksum ok.\n", info); + + memset(flags_debugmsg, 0, sizeof(flags_debugmsg)); + if (tcp_flags & 1) + strcat(flags_debugmsg, "FIN "); + if (tcp_flags & 2) + strcat(flags_debugmsg, "SYN "); + if (tcp_flags & 4) + strcat(flags_debugmsg, "RST "); + if (tcp_flags & 8) + strcat(flags_debugmsg, "PSH "); + if (tcp_flags & 16) + strcat(flags_debugmsg, "ACK "); + if (tcp_flags & 32) + strcat(flags_debugmsg, "URG "); + DEBUGP(DSNDCP, "%s: FLAGS: %s\n", info, flags_debugmsg); + } else if (data[9] == 0x11) { + DEBUGP(DSNDCP, "%s: Protocol type: UDP\n", info); + } else { + DEBUGP(DSNDCP, "%s: Protocol type: (%02x)\n", info, data[9]); + } + + DEBUGP(DSNDCP, "%s: IP-Header checksum errors: %d\n", info, + ip_csum_err_count); + DEBUGP(DSNDCP, "%s: TCP-Checksum errors: %d\n", info, + tcp_csum_err_count); +} +#endif /* Chapter 7.2: SN-PDU Formats */ struct sndcp_common_hdr { @@ -77,6 +202,14 @@ struct defrag_queue_entry { LLIST_HEAD(gprs_sndcp_entities); +/* Check if any compression parameters are set in the sgsn configuration */ +static inline int any_pcomp_or_dcomp_active(struct sgsn_instance *sgsn) { + if (sgsn->cfg.pcomp_rfc1144.active || sgsn->cfg.pcomp_rfc1144.passive) + return true; + else + return false; +} + /* Enqueue a fragment into the defragment queue */ static int defrag_enqueue(struct gprs_sndcp_entity *sne, uint8_t seg_nr, uint8_t *data, uint32_t data_len) @@ -143,6 +276,9 @@ static int defrag_segments(struct gprs_sndcp_entity *sne) struct msgb *msg; unsigned int seg_nr; uint8_t *npdu; + int npdu_len; + int rc; + uint8_t *expnd = NULL; LOGP(DSNDCP, LOGL_DEBUG, "TLLI=0x%08x NSAPI=%u: Defragment output PDU %u " "num_seg=%u tot_len=%u\n", sne->lle->llme->tlli, sne->nsapi, @@ -173,16 +309,58 @@ static int defrag_segments(struct gprs_sndcp_entity *sne) talloc_free(dqe); } + npdu_len = sne->defrag.tot_len; + /* FIXME: cancel timer */ /* actually send the N-PDU to the SGSN core code, which then * hands it off to the correct GTP tunnel + GGSN via gtp_data_req() */ - return sgsn_rx_sndcp_ud_ind(&sne->ra_id, sne->lle->llme->tlli, - sne->nsapi, msg, sne->defrag.tot_len, npdu); + + /* Decompress packet */ +#if DEBUG_IP_PACKETS == 1 + DEBUGP(DSNDCP, " \n"); + DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n"); + DEBUGP(DSNDCP, "===================================================\n"); +#endif + if (any_pcomp_or_dcomp_active(sgsn)) { + + expnd = talloc_zero_size(msg, npdu_len + MAX_HDRDECOMPR_INCR); + memcpy(expnd, npdu, npdu_len); + + /* Apply header decompression */ + rc = gprs_sndcp_pcomp_expand(expnd, npdu_len, sne->defrag.pcomp, + sne->defrag.proto); + if (rc < 0) { + LOGP(DSNDCP, LOGL_ERROR, + "TCP/IP Header decompression failed!\n"); + talloc_free(expnd); + return -EIO; + } + + /* Modify npu length, expnd is handed directly handed + * over to gsn_rx_sndcp_ud_ind(), see below */ + npdu_len = rc; + } else + expnd = npdu; +#if DEBUG_IP_PACKETS == 1 + debug_ip_packet(expnd, npdu_len, 1, "defrag_segments()"); + DEBUGP(DSNDCP, "===================================================\n"); + DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n"); + DEBUGP(DSNDCP, " \n"); +#endif + + /* Hand off packet to gtp */ + rc = sgsn_rx_sndcp_ud_ind(&sne->ra_id, sne->lle->llme->tlli, + sne->nsapi, msg, npdu_len, expnd); + + if (any_pcomp_or_dcomp_active(sgsn)) + talloc_free(expnd); + + return rc; } -static int defrag_input(struct gprs_sndcp_entity *sne, struct msgb *msg, uint8_t *hdr, - unsigned int len) +static int defrag_input(struct gprs_sndcp_entity *sne, struct msgb *msg, + uint8_t *hdr, unsigned int len) { struct sndcp_common_hdr *sch; struct sndcp_udata_hdr *suh; @@ -343,7 +521,8 @@ struct sndcp_frag_state { }; /* returns '1' if there are more fragments to send, '0' if none */ -static int sndcp_send_ud_frag(struct sndcp_frag_state *fs) +static int sndcp_send_ud_frag(struct sndcp_frag_state *fs, + uint8_t pcomp, uint8_t dcomp) { struct gprs_sndcp_entity *sne = fs->sne; struct gprs_llc_lle *lle = sne->lle; @@ -380,8 +559,8 @@ static int sndcp_send_ud_frag(struct sndcp_frag_state *fs) if (sch->first) { scomph = (struct sndcp_comp_hdr *) msgb_put(fmsg, sizeof(*scomph)); - scomph->pcomp = 0; - scomph->dcomp = 0; + scomph->pcomp = pcomp; + scomph->dcomp = dcomp; } /* append the user-data header */ @@ -446,9 +625,41 @@ int sndcp_unitdata_req(struct msgb *msg, struct gprs_llc_lle *lle, uint8_t nsapi struct sndcp_comp_hdr *scomph; struct sndcp_udata_hdr *suh; struct sndcp_frag_state fs; + uint8_t pcomp = 0; + uint8_t dcomp = 0; + int rc; /* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */ + /* Compress packet */ +#if DEBUG_IP_PACKETS == 1 + DEBUGP(DSNDCP, " \n"); + DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n"); + DEBUGP(DSNDCP, "===================================================\n"); + debug_ip_packet(msg->data, msg->len, 0, "sndcp_initdata_req()"); +#endif + if (any_pcomp_or_dcomp_active(sgsn)) { + + /* Apply header compression */ + rc = gprs_sndcp_pcomp_compress(msg->data, msg->len, &pcomp, + lle->llme->comp.proto, nsapi); + if (rc < 0) { + LOGP(DSNDCP, LOGL_ERROR, + "TCP/IP Header compression failed!\n"); + return -EIO; + } + + /* Fixup pointer locations and sizes in message buffer to match + * the new, compressed buffer size */ + msgb_get(msg, msg->len); + msgb_put(msg, rc); + } +#if DEBUG_IP_PACKETS == 1 + DEBUGP(DSNDCP, "===================================================\n"); + DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n"); + DEBUGP(DSNDCP, " \n"); +#endif + sne = gprs_sndcp_entity_by_lle(lle, nsapi); if (!sne) { LOGP(DSNDCP, LOGL_ERROR, "Cannot find SNDCP Entity\n"); @@ -469,7 +680,7 @@ int sndcp_unitdata_req(struct msgb *msg, struct gprs_llc_lle *lle, uint8_t nsapi /* call function to generate and send fragments until all * of the N-PDU has been sent */ while (1) { - int rc = sndcp_send_ud_frag(&fs); + int rc = sndcp_send_ud_frag(&fs,pcomp,dcomp); if (rc == 0) return 0; if (rc < 0) @@ -489,8 +700,8 @@ int sndcp_unitdata_req(struct msgb *msg, struct gprs_llc_lle *lle, uint8_t nsapi sne->tx_npdu_nr = (sne->tx_npdu_nr + 1) % 0xfff; scomph = (struct sndcp_comp_hdr *) msgb_push(msg, sizeof(*scomph)); - scomph->pcomp = 0; - scomph->dcomp = 0; + scomph->pcomp = pcomp; + scomph->dcomp = dcomp; /* prepend common SNDCP header */ sch = (struct sndcp_common_hdr *) msgb_push(msg, sizeof(*sch)); @@ -512,6 +723,8 @@ int sndcp_llunitdata_ind(struct msgb *msg, struct gprs_llc_lle *lle, uint8_t *npdu; uint16_t npdu_num __attribute__((unused)); int npdu_len; + int rc; + uint8_t *expnd = NULL; sch = (struct sndcp_common_hdr *) hdr; if (sch->first) { @@ -540,26 +753,70 @@ int sndcp_llunitdata_ind(struct msgb *msg, struct gprs_llc_lle *lle, /* FIXME: move this RA_ID up to the LLME or even higher */ bssgp_parse_cell_id(&sne->ra_id, msgb_bcid(msg)); + if(scomph) { + sne->defrag.pcomp = scomph->pcomp; + sne->defrag.dcomp = scomph->dcomp; + sne->defrag.proto = lle->llme->comp.proto; + sne->defrag.data = lle->llme->comp.data; + } + /* any non-first segment is by definition something to defragment * as is any segment that tells us there are more segments */ if (!sch->first || sch->more) return defrag_input(sne, msg, hdr, len); - if (scomph && (scomph->pcomp || scomph->dcomp)) { - LOGP(DSNDCP, LOGL_ERROR, "We don't support compression yet\n"); - return -EIO; - } - npdu_num = (suh->npdu_high << 8) | suh->npdu_low; npdu = (uint8_t *)suh + sizeof(*suh); - npdu_len = (msg->data + msg->len) - npdu; + npdu_len = (msg->data + msg->len) - npdu - 3; /* -3 'removes' the FCS */ + if (npdu_len <= 0) { LOGP(DSNDCP, LOGL_ERROR, "Short SNDCP N-PDU: %d\n", npdu_len); return -EIO; } /* actually send the N-PDU to the SGSN core code, which then * hands it off to the correct GTP tunnel + GGSN via gtp_data_req() */ - return sgsn_rx_sndcp_ud_ind(&sne->ra_id, lle->llme->tlli, sne->nsapi, msg, npdu_len, npdu); + + /* Decompress packet */ +#if DEBUG_IP_PACKETS == 1 + DEBUGP(DSNDCP, " \n"); + DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n"); + DEBUGP(DSNDCP, "===================================================\n"); +#endif + if (any_pcomp_or_dcomp_active(sgsn)) { + + expnd = talloc_zero_size(msg, npdu_len + MAX_HDRDECOMPR_INCR); + memcpy(expnd, npdu, npdu_len); + + /* Apply header decompression */ + rc = gprs_sndcp_pcomp_expand(expnd, npdu_len, sne->defrag.pcomp, + sne->defrag.proto); + if (rc < 0) { + LOGP(DSNDCP, LOGL_ERROR, + "TCP/IP Header decompression failed!\n"); + talloc_free(expnd); + return -EIO; + } + + /* Modify npu length, expnd is handed directly handed + * over to gsn_rx_sndcp_ud_ind(), see below */ + npdu_len = rc; + } else + expnd = npdu; +#if DEBUG_IP_PACKETS == 1 + debug_ip_packet(expnd, npdu_len, 1, "sndcp_llunitdata_ind()"); + DEBUGP(DSNDCP, "===================================================\n"); + DEBUGP(DSNDCP, ":::::::::::::::::::::::::::::::::::::::::::::::::::\n"); + DEBUGP(DSNDCP, " \n"); +#endif + + /* Hand off packet to gtp */ + rc = sgsn_rx_sndcp_ud_ind(&sne->ra_id, lle->llme->tlli, + sne->nsapi, msg, npdu_len, expnd); + + if (any_pcomp_or_dcomp_active(sgsn)) + talloc_free(expnd); + + return rc; } #if 0 @@ -619,3 +876,322 @@ static int sndcp_rx_llc_prim() case LL_STATUS_IND: } #endif + +/* Generate SNDCP-XID message */ +static int gprs_llc_gen_sndcp_xid(uint8_t *bytes, int bytes_len, uint8_t nsapi) +{ + int entity = 0; + LLIST_HEAD(comp_fields); + struct gprs_sndcp_pcomp_rfc1144_params rfc1144_params; + struct gprs_sndcp_comp_field rfc1144_comp_field; + + memset(&rfc1144_comp_field, 0, sizeof(struct gprs_sndcp_comp_field)); + + /* Setup rfc1144 */ + if (sgsn->cfg.pcomp_rfc1144.active) { + rfc1144_params.nsapi[0] = nsapi; + rfc1144_params.nsapi_len = 1; + rfc1144_params.s01 = sgsn->cfg.pcomp_rfc1144.s01; + rfc1144_comp_field.p = 1; + rfc1144_comp_field.entity = entity; + rfc1144_comp_field.algo = RFC_1144; + rfc1144_comp_field.comp[RFC1144_PCOMP1] = 1; + rfc1144_comp_field.comp[RFC1144_PCOMP2] = 2; + rfc1144_comp_field.comp_len = RFC1144_PCOMP_NUM; + rfc1144_comp_field.rfc1144_params = &rfc1144_params; + entity++; + llist_add(&rfc1144_comp_field.list, &comp_fields); + } + + /* Compile bytestream */ + return gprs_sndcp_compile_xid(bytes, bytes_len, &comp_fields); +} + +/* Set of SNDCP-XID bnegotiation (See also: TS 144 065, + * Section 6.8 XID parameter negotiation) */ +int sndcp_sn_xid_req(struct gprs_llc_lle *lle, uint8_t nsapi) +{ + /* Note: The specification requires the SNDCP-User to set of an + * SNDCP xid request. See also 3GPP TS 44.065, 6.8 XID parameter + * negotiation, Figure 11: SNDCP XID negotiation procedure. In + * our case the SNDCP-User is sgsn_libgtp.c, which calls + * sndcp_sn_xid_req directly. */ + + uint8_t l3params[1024]; + int xid_len; + struct gprs_llc_xid_field xid_field_request; + + /* Wipe off all compression entities and their states to + * get rid of possible leftovers from a previous session */ + gprs_sndcp_comp_free(lle->llme->comp.proto); + gprs_sndcp_comp_free(lle->llme->comp.data); + lle->llme->comp.proto = gprs_sndcp_comp_alloc(lle->llme); + lle->llme->comp.data = gprs_sndcp_comp_alloc(lle->llme); + talloc_free(lle->llme->xid); + lle->llme->xid = NULL; + + /* Generate compression parameter bytestream */ + xid_len = gprs_llc_gen_sndcp_xid(l3params, sizeof(l3params), nsapi); + + /* Send XID with the SNDCP-XID bytetsream included */ + if (xid_len > 0) { + xid_field_request.type = GPRS_LLC_XID_T_L3_PAR; + xid_field_request.data = l3params; + xid_field_request.data_len = xid_len; + return gprs_ll_xid_req(lle, &xid_field_request); + } + + /* When bytestream can not be generated, proceed without SNDCP-XID */ + return gprs_ll_xid_req(lle, NULL); + +} + +/* Handle header compression entites */ +static int handle_pcomp_entities(struct gprs_sndcp_comp_field *comp_field, + struct gprs_llc_lle *lle) +{ + /* Note: This functions also transforms the comp_field into its + * echo form (strips comp values, resets propose bit etc...) + * the processed comp_fields can then be sent back as XID- + * Response without further modification. */ + + /* Delete propose bit */ + comp_field->p = 0; + + /* Process proposed parameters */ + switch (comp_field->algo) { + case RFC_1144: + if (sgsn->cfg.pcomp_rfc1144.passive + && comp_field->rfc1144_params->nsapi_len > 0) { + DEBUGP(DSNDCP, + "Accepting RFC1144 header compression...\n"); + gprs_sndcp_comp_add(lle->llme, lle->llme->comp.proto, + comp_field); + } else { + DEBUGP(DSNDCP, + "Rejecting RFC1144 header compression...\n"); + gprs_sndcp_comp_delete(lle->llme->comp.proto, + comp_field->entity); + comp_field->rfc1144_params->nsapi_len = 0; + } + break; + case RFC_2507: + /* RFC 2507 is not yet supported, + * so we set applicable nsapis to zero */ + DEBUGP(DSNDCP, "Rejecting RFC2507 header compression...\n"); + comp_field->rfc2507_params->nsapi_len = 0; + gprs_sndcp_comp_delete(lle->llme->comp.proto, + comp_field->entity); + break; + case ROHC: + /* ROHC is not yet supported, + * so we set applicable nsapis to zero */ + DEBUGP(DSNDCP, "Rejecting ROHC header compression...\n"); + comp_field->rohc_params->nsapi_len = 0; + gprs_sndcp_comp_delete(lle->llme->comp.proto, + comp_field->entity); + break; + } + + return 0; +} + +/* Hanle data compression entites */ +static int handle_dcomp_entities(struct gprs_sndcp_comp_field *comp_field, + struct gprs_llc_lle *lle) +{ + /* See note in handle_pcomp_entities() */ + + /* Delete propose bit */ + comp_field->p = 0; + + /* Process proposed parameters */ + switch (comp_field->algo) { + case V42BIS: + /* V42BIS is not yet supported, + * so we set applicable nsapis to zero */ + LOGP(DSNDCP, LOGL_DEBUG, + "Rejecting V.42bis data compression...\n"); + comp_field->v42bis_params->nsapi_len = 0; + gprs_sndcp_comp_delete(lle->llme->comp.data, + comp_field->entity); + break; + case V44: + /* V44 is not yet supported, + * so we set applicable nsapis to zero */ + DEBUGP(DSNDCP, "Rejecting V.44 data compression...\n"); + comp_field->v44_params->nsapi_len = 0; + gprs_sndcp_comp_delete(lle->llme->comp.data, + comp_field->entity); + break; + } + + return 0; + +} + +/* Process SNDCP-XID indication + * (See also: TS 144 065, Section 6.8 XID parameter negotiation) */ +int sndcp_sn_xid_ind(struct gprs_llc_xid_field *xid_field_indication, + struct gprs_llc_xid_field *xid_field_response, + struct gprs_llc_lle *lle) +{ + /* Note: This function computes the SNDCP-XID response that is sent + * back to the ms when a ms originated XID is received. The + * Input XID fields are directly processed and the result is directly + * handed back. */ + + int rc; + int compclass; + + struct llist_head *comp_fields; + struct gprs_sndcp_comp_field *comp_field; + + OSMO_ASSERT(xid_field_indication); + OSMO_ASSERT(xid_field_response); + OSMO_ASSERT(lle); + + /* Parse SNDCP-CID XID-Field */ + comp_fields = gprs_sndcp_parse_xid(lle->llme, + xid_field_indication->data, + xid_field_indication->data_len, + NULL); + if (!comp_fields) + return -EINVAL; + + /* Don't bother with empty indications */ + if (llist_empty(comp_fields)) { + xid_field_response->data = NULL; + xid_field_response->data_len = 0; + DEBUGP(DSNDCP, + "SNDCP-XID indication did not contain any parameters!\n"); + return 0; + } + + /* Handle compression entites */ + DEBUGP(DSNDCP, "SNDCP-XID-IND (ms):\n"); + gprs_sndcp_dump_comp_fields(comp_fields, LOGL_DEBUG); + + llist_for_each_entry(comp_field, comp_fields, list) { + compclass = gprs_sndcp_get_compression_class(comp_field); + if (compclass == SNDCP_XID_PROTOCOL_COMPRESSION) + rc = handle_pcomp_entities(comp_field, lle); + else if (compclass == SNDCP_XID_DATA_COMPRESSION) + rc = handle_dcomp_entities(comp_field, lle); + else { + gprs_sndcp_comp_delete(lle->llme->comp.proto, + comp_field->entity); + gprs_sndcp_comp_delete(lle->llme->comp.data, + comp_field->entity); + rc = 0; + } + + if (rc < 0) { + talloc_free(comp_fields); + return -EINVAL; + } + } + + DEBUGP(DSNDCP, "SNDCP-XID-RES (sgsn):\n"); + gprs_sndcp_dump_comp_fields(comp_fields, LOGL_DEBUG); + + /* Reserve some memory to store the modified SNDCP-XID bytes */ + xid_field_response->data = + talloc_zero_size(lle->llme, xid_field_indication->data_len); + + /* Set Type flag for response */ + xid_field_response->type = GPRS_LLC_XID_T_L3_PAR; + + /* Compile modified SNDCP-XID bytes */ + rc = gprs_sndcp_compile_xid(xid_field_response->data, + xid_field_indication->data_len, + comp_fields); + + if (rc > 0) + xid_field_response->data_len = rc; + else { + talloc_free(xid_field_response->data); + xid_field_response->data = NULL; + xid_field_response->data_len = 0; + return -EINVAL; + } + + talloc_free(comp_fields); + + return 0; +} + +/* Process SNDCP-XID indication + * (See also: TS 144 065, Section 6.8 XID parameter negotiation) */ +int sndcp_sn_xid_conf(struct gprs_llc_xid_field *xid_field_conf, + struct gprs_llc_xid_field *xid_field_request, + struct gprs_llc_lle *lle) +{ + /* Note: This function handles an incomming SNDCP-XID confirmiation. + * Since the confirmation fields may lack important parameters we + * will reconstruct these missing fields using the original request + * we have sent. After that we will create (or delete) the + * compression entites */ + + struct llist_head *comp_fields_req; + struct llist_head *comp_fields_conf; + struct gprs_sndcp_comp_field *comp_field; + int rc; + int compclass; + + /* We need both, the confirmation that is sent back by the ms, + * and the original request we have sent. If one of this is missing + * we can not process the confirmation, the caller must check if + * request and confirmation fields are available. */ + OSMO_ASSERT(xid_field_conf); + OSMO_ASSERT(xid_field_request); + + /* Parse SNDCP-CID XID-Field */ + comp_fields_req = gprs_sndcp_parse_xid(lle->llme, + xid_field_request->data, + xid_field_request->data_len, + NULL); + if (!comp_fields_req) + return -EINVAL; + + DEBUGP(DSNDCP, "SNDCP-XID-REQ (sgsn):\n"); + gprs_sndcp_dump_comp_fields(comp_fields_req, LOGL_DEBUG); + + /* Parse SNDCP-CID XID-Field */ + comp_fields_conf = gprs_sndcp_parse_xid(lle->llme, + xid_field_conf->data, + xid_field_conf->data_len, + comp_fields_req); + if (!comp_fields_conf) + return -EINVAL; + + DEBUGP(DSNDCP, "SNDCP-XID-CONF (ms):\n"); + gprs_sndcp_dump_comp_fields(comp_fields_conf, LOGL_DEBUG); + + /* Handle compression entites */ + llist_for_each_entry(comp_field, comp_fields_conf, list) { + compclass = gprs_sndcp_get_compression_class(comp_field); + if (compclass == SNDCP_XID_PROTOCOL_COMPRESSION) + rc = handle_pcomp_entities(comp_field, lle); + else if (compclass == SNDCP_XID_DATA_COMPRESSION) + rc = handle_dcomp_entities(comp_field, lle); + else { + gprs_sndcp_comp_delete(lle->llme->comp.proto, + comp_field->entity); + gprs_sndcp_comp_delete(lle->llme->comp.data, + comp_field->entity); + rc = 0; + } + + if (rc < 0) { + talloc_free(comp_fields_req); + talloc_free(comp_fields_conf); + return -EINVAL; + } + } + + talloc_free(comp_fields_req); + talloc_free(comp_fields_conf); + + return 0; +} -- cgit v1.2.3