| /* GPRS LLC protocol implementation as per 3GPP TS 04.64 */ |
| |
| /* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org> |
| * |
| * All Rights Reserved |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU Affero General Public License as published by |
| * the Free Software Foundation; either version 3 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU Affero General Public License for more details. |
| * |
| * You should have received a copy of the GNU Affero General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| * |
| */ |
| |
| #include <errno.h> |
| #include <stdint.h> |
| #include <stdbool.h> |
| |
| #include <openssl/rand.h> |
| |
| #include <osmocom/core/msgb.h> |
| #include <osmocom/core/linuxlist.h> |
| #include <osmocom/core/timer.h> |
| #include <osmocom/core/talloc.h> |
| #include <osmocom/core/rate_ctr.h> |
| #include <osmocom/gprs/gprs_bssgp.h> |
| |
| #include <openbsc/gsm_data.h> |
| #include <openbsc/debug.h> |
| #include <openbsc/gprs_sgsn.h> |
| #include <openbsc/gprs_gmm.h> |
| #include <openbsc/gprs_llc.h> |
| #include <openbsc/crc24.h> |
| #include <openbsc/sgsn.h> |
| #include <openbsc/gprs_llc_xid.h> |
| #include <openbsc/gprs_sndcp_comp.h> |
| #include <openbsc/gprs_sndcp.h> |
| |
| static struct gprs_llc_llme *llme_alloc(uint32_t tlli); |
| static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg, |
| int command); |
| static int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi, |
| int command, enum gprs_llc_u_cmd u_cmd, int pf_bit); |
| |
| /* BEGIN XID RELATED */ |
| |
| /* Generate XID message */ |
| static int gprs_llc_generate_xid(uint8_t *bytes, int bytes_len, |
| struct gprs_llc_xid_field *l3_xid_field, |
| struct gprs_llc_llme *llme) |
| { |
| /* Note: Called by gprs_ll_xid_req() */ |
| |
| LLIST_HEAD(xid_fields); |
| |
| struct gprs_llc_xid_field xid_version; |
| struct gprs_llc_xid_field xid_n201u; |
| struct gprs_llc_xid_field xid_n201i; |
| |
| xid_version.type = GPRS_LLC_XID_T_VERSION; |
| xid_version.data = (uint8_t *) "\x00"; |
| xid_version.data_len = 1; |
| |
| xid_n201u.type = GPRS_LLC_XID_T_N201_U; |
| xid_n201u.data = (uint8_t *) "\x05\xf0"; |
| xid_n201u.data_len = 2; |
| |
| xid_n201i.type = GPRS_LLC_XID_T_N201_I; |
| xid_n201i.data = (uint8_t *) "\x05\xf0"; |
| xid_n201i.data_len = 2; |
| |
| /* Add locally managed XID Fields */ |
| llist_add(&xid_n201i.list, &xid_fields); |
| llist_add(&xid_n201u.list, &xid_fields); |
| llist_add(&xid_version.list, &xid_fields); |
| |
| /* Append layer 3 XID field (if present) */ |
| if (l3_xid_field) { |
| /* Enforce layer 3 XID type (just to be sure) */ |
| l3_xid_field->type = GPRS_LLC_XID_T_L3_PAR; |
| |
| /* Add Layer 3 XID field to the list */ |
| llist_add(&l3_xid_field->list, &xid_fields); |
| } |
| |
| /* Store generated XID for later reference */ |
| talloc_free(llme->xid); |
| llme->xid = gprs_llc_copy_xid(llme, &xid_fields); |
| |
| return gprs_llc_compile_xid(bytes, bytes_len, &xid_fields); |
| } |
| |
| /* Generate XID message that will cause the GMM to reset */ |
| static int gprs_llc_generate_xid_for_gmm_reset(uint8_t *bytes, |
| int bytes_len, uint32_t iov_ui, |
| struct gprs_llc_llme *llme) |
| { |
| /* Called by gprs_llgmm_reset() and |
| * gprs_llgmm_reset_oldmsg() */ |
| |
| LLIST_HEAD(xid_fields); |
| |
| struct gprs_llc_xid_field xid_reset; |
| struct gprs_llc_xid_field xid_iovui; |
| |
| /* First XID component must be RESET */ |
| xid_reset.type = GPRS_LLC_XID_T_RESET; |
| xid_reset.data = NULL; |
| xid_reset.data_len = 0; |
| |
| /* Add new IOV-UI */ |
| xid_iovui.type = GPRS_LLC_XID_T_IOV_UI; |
| xid_iovui.data = (uint8_t *) & iov_ui; |
| xid_iovui.data_len = 4; |
| |
| /* Add locally managed XID Fields */ |
| llist_add(&xid_iovui.list, &xid_fields); |
| llist_add(&xid_reset.list, &xid_fields); |
| |
| /* Store generated XID for later reference */ |
| talloc_free(llme->xid); |
| llme->xid = gprs_llc_copy_xid(llme, &xid_fields); |
| |
| return gprs_llc_compile_xid(bytes, bytes_len, &xid_fields); |
| } |
| |
| /* Process an incoming XID confirmation */ |
| static int gprs_llc_process_xid_conf(uint8_t *bytes, int bytes_len, |
| struct gprs_llc_lle *lle) |
| { |
| /* Note: This function handles the response of a network originated |
| * XID-Request. There XID messages reflected by the phone are analyzed |
| * and processed here. The caller is called by rx_llc_xid(). */ |
| |
| struct llist_head *xid_fields; |
| struct gprs_llc_xid_field *xid_field; |
| struct gprs_llc_xid_field *xid_field_request; |
| struct gprs_llc_xid_field *xid_field_request_l3 = NULL; |
| |
| /* Pick layer3 XID from the XID request we have sent last */ |
| if (lle->llme->xid) { |
| llist_for_each_entry(xid_field_request, lle->llme->xid, list) { |
| if (xid_field_request->type == GPRS_LLC_XID_T_L3_PAR) |
| xid_field_request_l3 = xid_field_request; |
| } |
| } |
| |
| /* Parse and analyze XID-Response */ |
| xid_fields = gprs_llc_parse_xid(NULL, bytes, bytes_len); |
| |
| if (xid_fields) { |
| |
| gprs_llc_dump_xid_fields(xid_fields, LOGL_DEBUG); |
| llist_for_each_entry(xid_field, xid_fields, list) { |
| |
| /* Forward SNDCP-XID fields to Layer 3 (SNDCP) */ |
| if (xid_field->type == GPRS_LLC_XID_T_L3_PAR && |
| xid_field_request_l3) { |
| sndcp_sn_xid_conf(xid_field, |
| xid_field_request_l3, lle); |
| } |
| |
| /* Process LLC-XID fields: */ |
| else { |
| |
| /* FIXME: Do something more useful with the |
| * echoed XID-Information. Currently we |
| * just ignore the response completely and |
| * by doing so we blindly accept any changes |
| * the MS might have done to the our XID |
| * inquiry. There is a remainig risk of |
| * malfunction! */ |
| LOGP(DLLC, LOGL_NOTICE, |
| "Ignoring XID-Field: XID: type=%d, data_len=%d, data=%s\n", |
| xid_field->type, xid_field->data_len, |
| osmo_hexdump_nospc(xid_field->data, |
| xid_field->data_len)); |
| } |
| } |
| talloc_free(xid_fields); |
| } |
| |
| /* Flush pending XID fields */ |
| talloc_free(lle->llme->xid); |
| lle->llme->xid = NULL; |
| |
| return 0; |
| } |
| |
| /* Process an incoming XID indication and generate an appropiate response */ |
| static int gprs_llc_process_xid_ind(uint8_t *bytes_request, |
| int bytes_request_len, |
| uint8_t *bytes_response, |
| int bytes_response_maxlen, |
| struct gprs_llc_lle *lle) |
| { |
| /* Note: This function computes the response that is sent back to the |
| * phone when a phone originated XID is received. The function is |
| * called by rx_llc_xid() */ |
| |
| int rc = -EINVAL; |
| |
| struct llist_head *xid_fields; |
| struct llist_head *xid_fields_response; |
| |
| struct gprs_llc_xid_field *xid_field; |
| struct gprs_llc_xid_field *xid_field_response; |
| |
| /* Parse and analyze XID-Request */ |
| xid_fields = |
| gprs_llc_parse_xid(lle->llme, bytes_request, bytes_request_len); |
| if (xid_fields) { |
| xid_fields_response = talloc_zero(lle->llme, struct llist_head); |
| INIT_LLIST_HEAD(xid_fields_response); |
| gprs_llc_dump_xid_fields(xid_fields, LOGL_DEBUG); |
| |
| /* Process LLC-XID fields: */ |
| llist_for_each_entry(xid_field, xid_fields, list) { |
| |
| if (xid_field->type != GPRS_LLC_XID_T_L3_PAR) { |
| /* FIXME: Check the incoming XID parameters for |
| * for validity. Currently we just blindly |
| * accept all XID fields by just echoing them. |
| * There is a remaining risk of malfunction |
| * when a phone submits values which defer from |
| * the default! */ |
| LOGP(DLLC, LOGL_NOTICE, |
| "Echoing XID-Field: XID: type=%d, data_len=%d, data=%s\n", |
| xid_field->type, xid_field->data_len, |
| osmo_hexdump_nospc(xid_field->data, |
| xid_field->data_len)); |
| xid_field_response = |
| gprs_llc_dup_xid_field |
| (lle->llme, xid_field); |
| llist_add(&xid_field_response->list, |
| xid_fields_response); |
| } |
| } |
| |
| /* Forward SNDCP-XID fields to Layer 3 (SNDCP) */ |
| llist_for_each_entry(xid_field, xid_fields, list) { |
| if (xid_field->type == GPRS_LLC_XID_T_L3_PAR) { |
| |
| xid_field_response = |
| talloc_zero(lle->llme, |
| struct gprs_llc_xid_field); |
| rc = sndcp_sn_xid_ind(xid_field, |
| xid_field_response, lle); |
| if (rc == 0) |
| llist_add(&xid_field_response->list, |
| xid_fields_response); |
| else |
| talloc_free(xid_field_response); |
| } |
| } |
| |
| rc = gprs_llc_compile_xid(bytes_response, |
| bytes_response_maxlen, |
| xid_fields_response); |
| talloc_free(xid_fields_response); |
| talloc_free(xid_fields); |
| } |
| |
| return rc; |
| } |
| |
| /* Dispatch XID indications and responses comming from the Phone */ |
| static void rx_llc_xid(struct gprs_llc_lle *lle, |
| struct gprs_llc_hdr_parsed *gph) |
| { |
| uint8_t response[1024]; |
| int response_len; |
| |
| /* FIXME: 8.5.3.3: check if XID is invalid */ |
| if (gph->is_cmd) { |
| LOGP(DLLC, LOGL_NOTICE, |
| "Received XID indication from phone.\n"); |
| |
| struct msgb *resp; |
| uint8_t *xid; |
| resp = msgb_alloc_headroom(4096, 1024, "LLC_XID"); |
| |
| response_len = |
| gprs_llc_process_xid_ind(gph->data, gph->data_len, |
| response, sizeof(response), |
| lle); |
| if (response_len < 0) { |
| LOGP(DLLC, LOGL_ERROR, |
| "invalid XID indication received!\n"); |
| } else { |
| xid = msgb_put(resp, response_len); |
| memcpy(xid, response, response_len); |
| } |
| gprs_llc_tx_xid(lle, resp, 0); |
| } else { |
| LOGP(DLLC, LOGL_NOTICE, |
| "Received XID confirmation from phone.\n"); |
| gprs_llc_process_xid_conf(gph->data, gph->data_len, lle); |
| /* FIXME: if we had sent a XID reset, send |
| * LLGMM-RESET.conf to GMM */ |
| } |
| } |
| |
| |
| /* Set of LL-XID negotiation (See also: TS 101 351, Section 7.2.2.4) */ |
| int gprs_ll_xid_req(struct gprs_llc_lle *lle, |
| struct gprs_llc_xid_field *l3_xid_field) |
| { |
| /* Note: This functions is calle from gprs_sndcp.c */ |
| |
| uint8_t xid_bytes[1024];; |
| int xid_bytes_len; |
| uint8_t *xid; |
| struct msgb *msg; |
| |
| /* Generate XID */ |
| xid_bytes_len = |
| gprs_llc_generate_xid(xid_bytes, sizeof(xid_bytes), |
| l3_xid_field, lle->llme); |
| |
| /* Only perform XID sending if the XID message contains something */ |
| if (xid_bytes_len > 0) { |
| /* Transmit XID bytes */ |
| msg = msgb_alloc_headroom(4096, 1024, "LLC_XID"); |
| xid = msgb_put(msg, xid_bytes_len); |
| memcpy(xid, xid_bytes, xid_bytes_len); |
| LOGP(DLLC, LOGL_NOTICE, "Sending XID request to phone...\n"); |
| gprs_llc_tx_xid(lle, msg, 1); |
| } else { |
| LOGP(DLLC, LOGL_ERROR, |
| "XID-Message generation failed, XID not sent!\n"); |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| /* END XID RELATED */ |
| |
| |
| |
| |
| /* Entry function from upper level (LLC), asking us to transmit a BSSGP PDU |
| * to a remote MS (identified by TLLI) at a BTS identified by its BVCI and NSEI */ |
| static int _bssgp_tx_dl_ud(struct msgb *msg, struct sgsn_mm_ctx *mmctx) |
| { |
| struct bssgp_dl_ud_par dup; |
| const uint8_t qos_profile_default[3] = { 0x00, 0x00, 0x20 }; |
| |
| memset(&dup, 0, sizeof(dup)); |
| /* before we have received some identity from the MS, we might |
| * not yet have a MMC context (e.g. XID negotiation of primarly |
| * LLC connection from GMM sapi). */ |
| if (mmctx) { |
| dup.imsi = mmctx->imsi; |
| dup.drx_parms = mmctx->drx_parms; |
| dup.ms_ra_cap.len = mmctx->ms_radio_access_capa.len; |
| dup.ms_ra_cap.v = mmctx->ms_radio_access_capa.buf; |
| |
| /* make sure we only send it to the right llme */ |
| OSMO_ASSERT(msgb_tlli(msg) == mmctx->gb.llme->tlli |
| || msgb_tlli(msg) == mmctx->gb.llme->old_tlli); |
| } |
| memcpy(&dup.qos_profile, qos_profile_default, |
| sizeof(qos_profile_default)); |
| |
| return bssgp_tx_dl_ud(msg, 1000, &dup); |
| } |
| |
| |
| /* Section 8.9.9 LLC layer parameter default values */ |
| static const struct gprs_llc_params llc_default_params[NUM_SAPIS] = { |
| [1] = { |
| .t200_201 = 5, |
| .n200 = 3, |
| .n201_u = 400, |
| }, |
| [2] = { |
| .t200_201 = 5, |
| .n200 = 3, |
| .n201_u = 270, |
| }, |
| [3] = { |
| .iov_i_exp = 27, |
| .t200_201 = 5, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 1520, |
| .mU = 1520, |
| .kD = 16, |
| .kU = 16, |
| }, |
| [5] = { |
| .iov_i_exp = 27, |
| .t200_201 = 10, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 760, |
| .mU = 760, |
| .kD = 8, |
| .kU = 8, |
| }, |
| [7] = { |
| .t200_201 = 20, |
| .n200 = 3, |
| .n201_u = 270, |
| }, |
| [8] = { |
| .t200_201 = 20, |
| .n200 = 3, |
| .n201_u = 270, |
| }, |
| [9] = { |
| .iov_i_exp = 27, |
| .t200_201 = 20, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 380, |
| .mU = 380, |
| .kD = 4, |
| .kU = 4, |
| }, |
| [11] = { |
| .iov_i_exp = 27, |
| .t200_201 = 40, |
| .n200 = 3, |
| .n201_u = 500, |
| .n201_i = 1503, |
| .mD = 190, |
| .mU = 190, |
| .kD = 2, |
| .kU = 2, |
| }, |
| }; |
| |
| LLIST_HEAD(gprs_llc_llmes); |
| void *llc_tall_ctx; |
| |
| /* lookup LLC Entity based on DLCI (TLLI+SAPI tuple) */ |
| static struct gprs_llc_lle *lle_by_tlli_sapi(const uint32_t tlli, uint8_t sapi) |
| { |
| struct gprs_llc_llme *llme; |
| |
| llist_for_each_entry(llme, &gprs_llc_llmes, list) { |
| if (llme->tlli == tlli || llme->old_tlli == tlli) |
| return &llme->lle[sapi]; |
| } |
| return NULL; |
| } |
| |
| struct gprs_llc_lle *gprs_lle_get_or_create(const uint32_t tlli, uint8_t sapi) |
| { |
| struct gprs_llc_llme *llme; |
| struct gprs_llc_lle *lle; |
| |
| lle = lle_by_tlli_sapi(tlli, sapi); |
| if (lle) |
| return lle; |
| |
| LOGP(DLLC, LOGL_NOTICE, "LLC: unknown TLLI 0x%08x, " |
| "creating LLME on the fly\n", tlli); |
| llme = llme_alloc(tlli); |
| lle = &llme->lle[sapi]; |
| return lle; |
| } |
| |
| struct llist_head *gprs_llme_list(void) |
| { |
| return &gprs_llc_llmes; |
| } |
| |
| /* lookup LLC Entity for RX based on DLCI (TLLI+SAPI tuple) */ |
| static struct gprs_llc_lle *lle_for_rx_by_tlli_sapi(const uint32_t tlli, |
| uint8_t sapi, enum gprs_llc_cmd cmd) |
| { |
| struct gprs_llc_lle *lle; |
| |
| /* We already know about this TLLI */ |
| lle = lle_by_tlli_sapi(tlli, sapi); |
| if (lle) |
| return lle; |
| |
| /* Maybe it is a routing area update but we already know this sapi? */ |
| if (gprs_tlli_type(tlli) == TLLI_FOREIGN) { |
| lle = lle_by_tlli_sapi(tlli, sapi); |
| if (lle) { |
| LOGP(DLLC, LOGL_NOTICE, |
| "LLC RX: Found a local entry for TLLI 0x%08x\n", |
| tlli); |
| return lle; |
| } |
| } |
| |
| /* 7.2.1.1 LLC belonging to unassigned TLLI+SAPI shall be discarded, |
| * except UID and XID frames with SAPI=1 */ |
| if (sapi == GPRS_SAPI_GMM && |
| (cmd == GPRS_LLC_XID || cmd == GPRS_LLC_UI)) { |
| struct gprs_llc_llme *llme; |
| /* FIXME: don't use the TLLI but the 0xFFFF unassigned? */ |
| llme = llme_alloc(tlli); |
| LOGP(DLLC, LOGL_NOTICE, "LLC RX: unknown TLLI 0x%08x, " |
| "creating LLME on the fly\n", tlli); |
| lle = &llme->lle[sapi]; |
| return lle; |
| } |
| |
| LOGP(DLLC, LOGL_NOTICE, |
| "unknown TLLI(0x%08x)/SAPI(%d): Silently dropping\n", |
| tlli, sapi); |
| return NULL; |
| } |
| |
| static void lle_init(struct gprs_llc_llme *llme, uint8_t sapi) |
| { |
| struct gprs_llc_lle *lle = &llme->lle[sapi]; |
| |
| lle->llme = llme; |
| lle->sapi = sapi; |
| lle->state = GPRS_LLES_UNASSIGNED; |
| |
| /* Initialize according to parameters */ |
| memcpy(&lle->params, &llc_default_params[sapi], sizeof(lle->params)); |
| } |
| |
| static struct gprs_llc_llme *llme_alloc(uint32_t tlli) |
| { |
| struct gprs_llc_llme *llme; |
| uint32_t i; |
| |
| llme = talloc_zero(llc_tall_ctx, struct gprs_llc_llme); |
| if (!llme) |
| return NULL; |
| |
| llme->tlli = tlli; |
| llme->old_tlli = 0xffffffff; |
| llme->state = GPRS_LLMS_UNASSIGNED; |
| llme->age_timestamp = GPRS_LLME_RESET_AGE; |
| llme->cksn = GSM_KEY_SEQ_INVAL; |
| |
| for (i = 0; i < ARRAY_SIZE(llme->lle); i++) |
| lle_init(llme, i); |
| |
| llist_add(&llme->list, &gprs_llc_llmes); |
| |
| llme->comp.proto = gprs_sndcp_comp_alloc(llme); |
| llme->comp.data = gprs_sndcp_comp_alloc(llme); |
| |
| return llme; |
| } |
| |
| static void llme_free(struct gprs_llc_llme *llme) |
| { |
| gprs_sndcp_comp_free(llme->comp.proto); |
| gprs_sndcp_comp_free(llme->comp.data); |
| talloc_free(llme->xid); |
| llist_del(&llme->list); |
| talloc_free(llme); |
| } |
| |
| #if 0 |
| /* FIXME: Unused code... */ |
| static void t200_expired(void *data) |
| { |
| struct gprs_llc_lle *lle = data; |
| |
| /* 8.5.1.3: Expiry of T200 */ |
| |
| if (lle->retrans_ctr >= lle->params.n200) { |
| /* FIXME: LLGM-STATUS-IND, LL-RELEASE-IND/CNF */ |
| lle->state = GPRS_LLES_ASSIGNED_ADM; |
| } |
| |
| switch (lle->state) { |
| case GPRS_LLES_LOCAL_EST: |
| /* FIXME: retransmit SABM */ |
| /* FIXME: re-start T200 */ |
| lle->retrans_ctr++; |
| break; |
| case GPRS_LLES_LOCAL_REL: |
| /* FIXME: retransmit DISC */ |
| /* FIXME: re-start T200 */ |
| lle->retrans_ctr++; |
| break; |
| default: |
| LOGP(DLLC, LOGL_ERROR, "LLC unhandled state: %d\n", lle->state); |
| break; |
| } |
| |
| } |
| |
| static void t201_expired(void *data) |
| { |
| struct gprs_llc_lle *lle = data; |
| |
| if (lle->retrans_ctr < lle->params.n200) { |
| /* FIXME: transmit apropriate supervisory frame (8.6.4.1) */ |
| /* FIXME: set timer T201 */ |
| lle->retrans_ctr++; |
| } |
| } |
| #endif |
| |
| int gprs_llc_tx_u(struct msgb *msg, uint8_t sapi, int command, |
| enum gprs_llc_u_cmd u_cmd, int pf_bit) |
| { |
| uint8_t *fcs, *llch; |
| uint8_t addr, ctrl; |
| uint32_t fcs_calc; |
| |
| /* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */ |
| |
| /* Address Field */ |
| addr = sapi & 0xf; |
| if (command) |
| addr |= 0x40; |
| |
| /* 6.3 Figure 8 */ |
| ctrl = 0xe0 | u_cmd; |
| if (pf_bit) |
| ctrl |= 0x10; |
| |
| /* prepend LLC UI header */ |
| llch = msgb_push(msg, 2); |
| llch[0] = addr; |
| llch[1] = ctrl; |
| |
| /* append FCS to end of frame */ |
| fcs = msgb_put(msg, 3); |
| fcs_calc = gprs_llc_fcs(llch, fcs - llch); |
| fcs[0] = fcs_calc & 0xff; |
| fcs[1] = (fcs_calc >> 8) & 0xff; |
| fcs[2] = (fcs_calc >> 16) & 0xff; |
| |
| /* Identifiers passed down: (BVCI, NSEI) */ |
| |
| rate_ctr_inc(&sgsn->rate_ctrs->ctr[CTR_LLC_DL_PACKETS]); |
| rate_ctr_add(&sgsn->rate_ctrs->ctr[CTR_LLC_DL_BYTES], msg->len); |
| |
| /* Send BSSGP-DL-UNITDATA.req */ |
| return _bssgp_tx_dl_ud(msg, NULL); |
| } |
| |
| /* Send XID response to LLE */ |
| static int gprs_llc_tx_xid(struct gprs_llc_lle *lle, struct msgb *msg, |
| int command) |
| { |
| /* copy identifiers from LLE to ensure lower layers can route */ |
| msgb_tlli(msg) = lle->llme->tlli; |
| msgb_bvci(msg) = lle->llme->bvci; |
| msgb_nsei(msg) = lle->llme->nsei; |
| |
| return gprs_llc_tx_u(msg, lle->sapi, command, GPRS_LLC_U_XID, 1); |
| } |
| |
| /* encrypt information field + FCS, if needed! */ |
| static int apply_gea(struct gprs_llc_lle *lle, uint16_t crypt_len, uint16_t nu, |
| uint32_t oc, uint8_t sapi, uint8_t *fcs, uint8_t *data) |
| { |
| uint8_t cipher_out[GSM0464_CIPH_MAX_BLOCK]; |
| |
| if (lle->llme->algo == GPRS_ALGO_GEA0) |
| return -EINVAL; |
| |
| /* Compute the 'Input' Paraemeter */ |
| uint32_t fcs_calc, iv = gprs_cipher_gen_input_ui(lle->llme->iov_ui, sapi, |
| nu, oc); |
| /* Compute gamma that we need to XOR with the data */ |
| int r = gprs_cipher_run(cipher_out, crypt_len, lle->llme->algo, |
| lle->llme->kc, iv, |
| fcs ? GPRS_CIPH_SGSN2MS : GPRS_CIPH_MS2SGSN); |
| if (r < 0) { |
| LOGP(DLLC, LOGL_ERROR, "Error producing %s gamma for UI " |
| "frame: %d\n", get_value_string(gprs_cipher_names, |
| lle->llme->algo), r); |
| return -ENOMSG; |
| } |
| |
| if (fcs) { |
| /* Mark frame as encrypted and update FCS */ |
| data[2] |= 0x02; |
| fcs_calc = gprs_llc_fcs(data, fcs - data); |
| fcs[0] = fcs_calc & 0xff; |
| fcs[1] = (fcs_calc >> 8) & 0xff; |
| fcs[2] = (fcs_calc >> 16) & 0xff; |
| data += 3; |
| } |
| |
| /* XOR the cipher output with the data */ |
| for (r = 0; r < crypt_len; r++) |
| *(data + r) ^= cipher_out[r]; |
| |
| return 0; |
| } |
| |
| /* Transmit a UI frame over the given SAPI: |
| 'encryptable' indicates whether particular message can be encrypted according |
| to 3GPP TS 24.008 § 4.7.1.2 |
| */ |
| int gprs_llc_tx_ui(struct msgb *msg, uint8_t sapi, int command, |
| struct sgsn_mm_ctx *mmctx, bool encryptable) |
| { |
| struct gprs_llc_lle *lle; |
| uint8_t *fcs, *llch; |
| uint8_t addr, ctrl[2]; |
| uint32_t fcs_calc; |
| uint16_t nu = 0; |
| uint32_t oc; |
| |
| /* Identifiers from UP: (TLLI, SAPI) + (BVCI, NSEI) */ |
| |
| /* look-up or create the LL Entity for this (TLLI, SAPI) tuple */ |
| lle = gprs_lle_get_or_create(msgb_tlli(msg), sapi); |
| |
| if (msg->len > lle->params.n201_u) { |
| LOGP(DLLC, LOGL_ERROR, "Cannot Tx %u bytes (N201-U=%u)\n", |
| msg->len, lle->params.n201_u); |
| msgb_free(msg); |
| return -EFBIG; |
| } |
| |
| gprs_llme_copy_key(mmctx, lle->llme); |
| |
| /* Update LLE's (BVCI, NSEI) tuple */ |
| lle->llme->bvci = msgb_bvci(msg); |
| lle->llme->nsei = msgb_nsei(msg); |
| |
| /* Obtain current values for N(u) and OC */ |
| nu = lle->vu_send; |
| oc = lle->oc_ui_send; |
| /* Increment V(U) */ |
| lle->vu_send = (lle->vu_send + 1) % 512; |
| /* Increment Overflow Counter, if needed */ |
| if ((lle->vu_send + 1) / 512) |
| lle->oc_ui_send += 512; |
| |
| /* Address Field */ |
| addr = sapi & 0xf; |
| if (command) |
| addr |= 0x40; |
| |
| /* Control Field */ |
| ctrl[0] = 0xc0; |
| ctrl[0] |= nu >> 6; |
| ctrl[1] = (nu << 2) & 0xfc; |
| ctrl[1] |= 0x01; /* Protected Mode */ |
| |
| /* prepend LLC UI header */ |
| llch = msgb_push(msg, 3); |
| llch[0] = addr; |
| llch[1] = ctrl[0]; |
| llch[2] = ctrl[1]; |
| |
| /* append FCS to end of frame */ |
| fcs = msgb_put(msg, 3); |
| fcs_calc = gprs_llc_fcs(llch, fcs - llch); |
| fcs[0] = fcs_calc & 0xff; |
| fcs[1] = (fcs_calc >> 8) & 0xff; |
| fcs[2] = (fcs_calc >> 16) & 0xff; |
| |
| if (lle->llme->algo != GPRS_ALGO_GEA0 && encryptable) { |
| int rc = apply_gea(lle, fcs - llch, nu, oc, sapi, fcs, llch); |
| if (rc < 0) { |
| msgb_free(msg); |
| return rc; |
| } |
| } |
| |
| rate_ctr_inc(&sgsn->rate_ctrs->ctr[CTR_LLC_DL_PACKETS]); |
| rate_ctr_add(&sgsn->rate_ctrs->ctr[CTR_LLC_DL_BYTES], msg->len); |
| |
| /* Identifiers passed down: (BVCI, NSEI) */ |
| |
| /* Send BSSGP-DL-UNITDATA.req */ |
| return _bssgp_tx_dl_ud(msg, mmctx); |
| } |
| |
| static int gprs_llc_hdr_rx(struct gprs_llc_hdr_parsed *gph, |
| struct gprs_llc_lle *lle) |
| { |
| switch (gph->cmd) { |
| case GPRS_LLC_SABM: /* Section 6.4.1.1 */ |
| lle->v_sent = lle->v_ack = lle->v_recv = 0; |
| if (lle->state == GPRS_LLES_ASSIGNED_ADM) { |
| /* start re-establishment (8.7.1) */ |
| } |
| lle->state = GPRS_LLES_REMOTE_EST; |
| /* FIXME: Send UA */ |
| lle->state = GPRS_LLES_ABM; |
| /* FIXME: process data */ |
| break; |
| case GPRS_LLC_DISC: /* Section 6.4.1.2 */ |
| /* FIXME: Send UA */ |
| /* terminate ABM */ |
| lle->state = GPRS_LLES_ASSIGNED_ADM; |
| break; |
| case GPRS_LLC_UA: /* Section 6.4.1.3 */ |
| if (lle->state == GPRS_LLES_LOCAL_EST) |
| lle->state = GPRS_LLES_ABM; |
| break; |
| case GPRS_LLC_DM: /* Section 6.4.1.4: ABM cannot be performed */ |
| if (lle->state == GPRS_LLES_LOCAL_EST) |
| lle->state = GPRS_LLES_ASSIGNED_ADM; |
| break; |
| case GPRS_LLC_FRMR: /* Section 6.4.1.5 */ |
| break; |
| case GPRS_LLC_XID: /* Section 6.4.1.6 */ |
| rx_llc_xid(lle, gph); |
| break; |
| case GPRS_LLC_UI: |
| if (gprs_llc_is_retransmit(gph->seq_tx, lle->vu_recv)) { |
| LOGP(DLLC, LOGL_NOTICE, |
| "TLLI=%08x dropping UI, N(U=%d) not in window V(URV(UR:%d).\n", |
| lle->llme ? lle->llme->tlli : -1, |
| gph->seq_tx, lle->vu_recv); |
| |
| /* HACK: non-standard recovery handling. If remote LLE |
| * is re-transmitting the same sequence number for |
| * three times, don't discard the frame but pass it on |
| * and 'learn' the new sequence number */ |
| if (gph->seq_tx != lle->vu_recv_last) { |
| lle->vu_recv_last = gph->seq_tx; |
| lle->vu_recv_duplicates = 0; |
| } else { |
| lle->vu_recv_duplicates++; |
| if (lle->vu_recv_duplicates < 3) |
| return -EIO; |
| LOGP(DLLC, LOGL_NOTICE, "TLLI=%08x recovering " |
| "N(U=%d) after receiving %u duplicates\n", |
| lle->llme ? lle->llme->tlli : -1, |
| gph->seq_tx, lle->vu_recv_duplicates); |
| } |
| } |
| /* Increment the sequence number that we expect in the next frame */ |
| lle->vu_recv = (gph->seq_tx + 1) % 512; |
| /* Increment Overflow Counter */ |
| if ((gph->seq_tx + 1) / 512) |
| lle->oc_ui_recv += 512; |
| break; |
| default: |
| LOGP(DLLC, LOGL_NOTICE, "Unhandled command: %d\n", gph->cmd); |
| break; |
| } |
| |
| return 0; |
| } |
| |
| /* receive an incoming LLC PDU (BSSGP-UL-UNITDATA-IND, 7.2.4.2) */ |
| int gprs_llc_rcvmsg(struct msgb *msg, struct tlv_parsed *tv) |
| { |
| struct gprs_llc_hdr *lh = (struct gprs_llc_hdr *) msgb_llch(msg); |
| struct gprs_llc_hdr_parsed llhp; |
| struct gprs_llc_lle *lle; |
| bool drop_cipherable = false; |
| int rc = 0; |
| |
| /* Identifiers from DOWN: NSEI, BVCI, TLLI */ |
| |
| memset(&llhp, 0, sizeof(llhp)); |
| rc = gprs_llc_hdr_parse(&llhp, (uint8_t *) lh, TLVP_LEN(tv, BSSGP_IE_LLC_PDU)); |
| gprs_llc_hdr_dump(&llhp); |
| if (rc < 0) { |
| LOGP(DLLC, LOGL_NOTICE, "Error during LLC header parsing\n"); |
| return rc; |
| } |
| |
| switch (gprs_tlli_type(msgb_tlli(msg))) { |
| case TLLI_LOCAL: |
| case TLLI_FOREIGN: |
| case TLLI_RANDOM: |
| case TLLI_AUXILIARY: |
| break; |
| default: |
| LOGP(DLLC, LOGL_ERROR, |
| "Discarding frame with strange TLLI type\n"); |
| break; |
| } |
| |
| /* find the LLC Entity for this TLLI+SAPI tuple */ |
| lle = lle_for_rx_by_tlli_sapi(msgb_tlli(msg), llhp.sapi, llhp.cmd); |
| if (!lle) { |
| switch (llhp.sapi) { |
| case GPRS_SAPI_SNDCP3: |
| case GPRS_SAPI_SNDCP5: |
| case GPRS_SAPI_SNDCP9: |
| case GPRS_SAPI_SNDCP11: |
| /* Ask an upper layer for help. */ |
| return gsm0408_gprs_force_reattach_oldmsg(msg, NULL); |
| default: |
| break; |
| } |
| return 0; |
| } |
| |
| /* reset age computation */ |
| lle->llme->age_timestamp = GPRS_LLME_RESET_AGE; |
| |
| /* decrypt information field + FCS, if needed! */ |
| if (llhp.is_encrypted) { |
| if (lle->llme->algo != GPRS_ALGO_GEA0) { |
| rc = apply_gea(lle, llhp.data_len + 3, llhp.seq_tx, |
| lle->oc_ui_recv, lle->sapi, NULL, |
| llhp.data); |
| if (rc < 0) |
| return rc; |
| llhp.fcs = *(llhp.data + llhp.data_len); |
| llhp.fcs |= *(llhp.data + llhp.data_len + 1) << 8; |
| llhp.fcs |= *(llhp.data + llhp.data_len + 2) << 16; |
| } else { |
| LOGP(DLLC, LOGL_NOTICE, "encrypted frame for LLC that " |
| "has no KC/Algo! Dropping.\n"); |
| return 0; |
| } |
| } else { |
| if (lle->llme->algo != GPRS_ALGO_GEA0 && |
| lle->llme->cksn != GSM_KEY_SEQ_INVAL) |
| drop_cipherable = true; |
| } |
| |
| /* We have to do the FCS check _after_ decryption */ |
| llhp.fcs_calc = gprs_llc_fcs((uint8_t *)lh, llhp.crc_length); |
| if (llhp.fcs != llhp.fcs_calc) { |
| LOGP(DLLC, LOGL_INFO, "Dropping frame with invalid FCS\n"); |
| return -EIO; |
| } |
| |
| /* Update LLE's (BVCI, NSEI) tuple */ |
| lle->llme->bvci = msgb_bvci(msg); |
| lle->llme->nsei = msgb_nsei(msg); |
| |
| /* Receive and Process the actual LLC frame */ |
| rc = gprs_llc_hdr_rx(&llhp, lle); |
| if (rc < 0) |
| return rc; |
| |
| rate_ctr_inc(&sgsn->rate_ctrs->ctr[CTR_LLC_UL_PACKETS]); |
| rate_ctr_add(&sgsn->rate_ctrs->ctr[CTR_LLC_UL_BYTES], msg->len); |
| |
| /* llhp.data is only set when we need to send LL_[UNIT]DATA_IND up */ |
| if (llhp.cmd == GPRS_LLC_UI && llhp.data && llhp.data_len) { |
| msgb_gmmh(msg) = llhp.data; |
| switch (llhp.sapi) { |
| case GPRS_SAPI_GMM: |
| /* send LL_UNITDATA_IND to GMM */ |
| rc = gsm0408_gprs_rcvmsg_gb(msg, lle->llme, |
| drop_cipherable); |
| break; |
| case GPRS_SAPI_SNDCP3: |
| case GPRS_SAPI_SNDCP5: |
| case GPRS_SAPI_SNDCP9: |
| case GPRS_SAPI_SNDCP11: |
| /* send LL_DATA_IND/LL_UNITDATA_IND to SNDCP */ |
| rc = sndcp_llunitdata_ind(msg, lle, llhp.data, llhp.data_len); |
| break; |
| case GPRS_SAPI_SMS: |
| /* FIXME */ |
| case GPRS_SAPI_TOM2: |
| case GPRS_SAPI_TOM8: |
| /* FIXME: send LL_DATA_IND/LL_UNITDATA_IND to TOM */ |
| default: |
| LOGP(DLLC, LOGL_NOTICE, "Unsupported SAPI %u\n", llhp.sapi); |
| rc = -EINVAL; |
| break; |
| } |
| } |
| |
| return rc; |
| } |
| |
| /* Propagate crypto parameters MM -> LLME */ |
| void gprs_llme_copy_key(struct sgsn_mm_ctx *mm, struct gprs_llc_llme *llme) |
| { |
| if (!mm) |
| return; |
| if (mm->ciph_algo != GPRS_ALGO_GEA0) { |
| llme->algo = mm->ciph_algo; |
| if (llme->cksn != mm->auth_triplet.key_seq && |
| mm->auth_triplet.key_seq != GSM_KEY_SEQ_INVAL) { |
| memcpy(llme->kc, mm->auth_triplet.vec.kc, |
| gprs_cipher_key_length(mm->ciph_algo)); |
| llme->cksn = mm->auth_triplet.key_seq; |
| } |
| } else |
| llme->cksn = GSM_KEY_SEQ_INVAL; |
| } |
| |
| /* 04.64 Chapter 7.2.1.1 LLGMM-ASSIGN */ |
| int gprs_llgmm_assign(struct gprs_llc_llme *llme, |
| uint32_t old_tlli, uint32_t new_tlli) |
| { |
| unsigned int i; |
| |
| if (old_tlli == 0xffffffff && new_tlli != 0xffffffff) { |
| /* TLLI Assignment 8.3.1 */ |
| /* New TLLI shall be assigned and used when (re)transmitting LLC frames */ |
| /* If old TLLI != 0xffffffff was assigned to LLME, then TLLI |
| * old is unassigned. Only TLLI new shall be accepted when |
| * received from peer. */ |
| if (llme->old_tlli != 0xffffffff) { |
| llme->old_tlli = 0xffffffff; |
| llme->tlli = new_tlli; |
| } else { |
| /* If TLLI old == 0xffffffff was assigned to LLME, then this is |
| * TLLI assignmemt according to 8.3.1 */ |
| llme->old_tlli = 0xffffffff; |
| llme->tlli = new_tlli; |
| llme->state = GPRS_LLMS_ASSIGNED; |
| /* 8.5.3.1 For all LLE's */ |
| for (i = 0; i < ARRAY_SIZE(llme->lle); i++) { |
| struct gprs_llc_lle *l = &llme->lle[i]; |
| l->vu_send = l->vu_recv = 0; |
| l->retrans_ctr = 0; |
| l->state = GPRS_LLES_ASSIGNED_ADM; |
| /* FIXME Set parameters according to table 9 */ |
| } |
| } |
| } else if (old_tlli != 0xffffffff && new_tlli != 0xffffffff) { |
| /* TLLI Change 8.3.2 */ |
| /* Both TLLI Old and TLLI New are assigned; use New when |
| * (re)transmitting. Accept both Old and New on Rx */ |
| llme->old_tlli = old_tlli; |
| llme->tlli = new_tlli; |
| llme->state = GPRS_LLMS_ASSIGNED; |
| } else if (old_tlli != 0xffffffff && new_tlli == 0xffffffff) { |
| /* TLLI Unassignment 8.3.3) */ |
| llme->tlli = llme->old_tlli = 0; |
| llme->state = GPRS_LLMS_UNASSIGNED; |
| for (i = 0; i < ARRAY_SIZE(llme->lle); i++) { |
| struct gprs_llc_lle *l = &llme->lle[i]; |
| l->state = GPRS_LLES_UNASSIGNED; |
| } |
| llme_free(llme); |
| } else |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| /* TLLI unassignment */ |
| int gprs_llgmm_unassign(struct gprs_llc_llme *llme) |
| { |
| return gprs_llgmm_assign(llme, llme->tlli, 0xffffffff); |
| } |
| |
| /* Chapter 7.2.1.2 LLGMM-RESET.req */ |
| int gprs_llgmm_reset(struct gprs_llc_llme *llme) |
| { |
| struct msgb *msg = msgb_alloc_headroom(4096, 1024, "LLC_XID"); |
| struct gprs_llc_lle *lle = &llme->lle[1]; |
| uint8_t xid_bytes[1024]; |
| int xid_bytes_len; |
| uint8_t *xid; |
| |
| LOGP(DLLC, LOGL_NOTICE, "LLGM Reset\n"); |
| if (RAND_bytes((uint8_t *) &llme->iov_ui, 4) != 1) { |
| LOGP(DLLC, LOGL_NOTICE, "RAND_bytes failed for LLC XID reset, " |
| "falling back to rand()\n"); |
| llme->iov_ui = rand(); |
| } |
| |
| /* Generate XID message */ |
| xid_bytes_len = gprs_llc_generate_xid_for_gmm_reset(xid_bytes, |
| sizeof(xid_bytes),llme->iov_ui,llme); |
| if (xid_bytes_len < 0) |
| return -EINVAL; |
| xid = msgb_put(msg, xid_bytes_len); |
| memcpy(xid, xid_bytes, xid_bytes_len); |
| |
| /* Reset some of the LLC parameters. See GSM 04.64, 8.5.3.1 */ |
| lle->vu_recv = 0; |
| lle->vu_send = 0; |
| lle->oc_ui_send = 0; |
| lle->oc_ui_recv = 0; |
| |
| /* FIXME: Start T200, wait for XID response */ |
| return gprs_llc_tx_xid(lle, msg, 1); |
| } |
| |
| int gprs_llgmm_reset_oldmsg(struct msgb* oldmsg, uint8_t sapi, |
| struct gprs_llc_llme *llme) |
| { |
| struct msgb *msg = msgb_alloc_headroom(4096, 1024, "LLC_XID"); |
| uint8_t xid_bytes[1024]; |
| int xid_bytes_len; |
| uint8_t *xid; |
| |
| LOGP(DLLC, LOGL_NOTICE, "LLGM Reset\n"); |
| if (RAND_bytes((uint8_t *) &llme->iov_ui, 4) != 1) { |
| LOGP(DLLC, LOGL_NOTICE, "RAND_bytes failed for LLC XID reset, " |
| "falling back to rand()\n"); |
| llme->iov_ui = rand(); |
| } |
| |
| /* Generate XID message */ |
| xid_bytes_len = gprs_llc_generate_xid_for_gmm_reset(xid_bytes, |
| sizeof(xid_bytes),llme->iov_ui,llme); |
| if (xid_bytes_len < 0) |
| return -EINVAL; |
| xid = msgb_put(msg, xid_bytes_len); |
| memcpy(xid, xid_bytes, xid_bytes_len); |
| |
| /* FIXME: Start T200, wait for XID response */ |
| |
| msgb_tlli(msg) = msgb_tlli(oldmsg); |
| msgb_bvci(msg) = msgb_bvci(oldmsg); |
| msgb_nsei(msg) = msgb_nsei(oldmsg); |
| |
| return gprs_llc_tx_u(msg, sapi, 1, GPRS_LLC_U_XID, 1); |
| } |
| |
| int gprs_llc_init(const char *cipher_plugin_path) |
| { |
| return gprs_cipher_load(cipher_plugin_path); |
| } |