| /* MTP layer3 main handling code */ |
| /* |
| * (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org> |
| * (C) 2010 by On-Waves |
| * All Rights Reserved |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 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 General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| */ |
| #include <mtp_data.h> |
| #include <mtp_level3.h> |
| #include <cellmgr_debug.h> |
| |
| #include <osmocore/talloc.h> |
| |
| #include <osmocom/sccp/sccp.h> |
| |
| #include <arpa/inet.h> |
| |
| #include <string.h> |
| |
| static void *tall_mtp_ctx = NULL; |
| |
| static struct msgb *mtp_msg_alloc(struct mtp_link *link) |
| { |
| struct mtp_level_3_hdr *hdr; |
| struct msgb *msg = msgb_alloc_headroom(4096, 128, "mtp-msg"); |
| if (!msg) { |
| LOGP(DINP, LOGL_ERROR, "Failed to allocate mtp msg\n"); |
| return NULL; |
| } |
| |
| msg->l2h = msgb_put(msg, sizeof(*hdr)); |
| hdr = (struct mtp_level_3_hdr *) msg->l2h; |
| hdr->addr = MTP_ADDR(0x0, link->dpc, link->opc); |
| hdr->ni = link->ni; |
| hdr->spare = link->spare; |
| return msg; |
| } |
| |
| static struct msgb *mtp_create_sltm(struct mtp_link *link) |
| { |
| const uint8_t test_ptrn[14] = { 'G', 'S', 'M', 'M', 'M', 'S', }; |
| struct mtp_level_3_hdr *hdr; |
| struct mtp_level_3_mng *mng; |
| struct msgb *msg = mtp_msg_alloc(link); |
| uint8_t *data; |
| if (!msg) |
| return NULL; |
| |
| hdr = (struct mtp_level_3_hdr *) msg->l2h; |
| hdr->ser_ind = MTP_SI_MNT_REG_MSG; |
| |
| mng = (struct mtp_level_3_mng *) msgb_put(msg, sizeof(*mng)); |
| mng->cmn.h0 = MTP_TST_MSG_GRP; |
| mng->cmn.h1 = MTP_TST_MSG_SLTM; |
| mng->length = ARRAY_SIZE(test_ptrn); |
| |
| data = msgb_put(msg, ARRAY_SIZE(test_ptrn)); |
| memcpy(data, test_ptrn, ARRAY_SIZE(test_ptrn)); |
| |
| /* remember the last tst ptrn... once we have some */ |
| memcpy(link->test_ptrn, test_ptrn, ARRAY_SIZE(test_ptrn)); |
| |
| return msg; |
| } |
| |
| static struct msgb *mtp_create_slta(struct mtp_link *link, struct mtp_level_3_mng *in_mng, int l3_len) |
| { |
| struct mtp_level_3_hdr *hdr; |
| struct mtp_level_3_mng *mng; |
| struct msgb *out = mtp_msg_alloc(link); |
| |
| if (!out) |
| return NULL; |
| |
| hdr = (struct mtp_level_3_hdr *) out->l2h; |
| hdr->ser_ind = MTP_SI_MNT_REG_MSG; |
| mng = (struct mtp_level_3_mng *) msgb_put(out, sizeof(*mng)); |
| mng->cmn.h0 = MTP_TST_MSG_GRP; |
| mng->cmn.h1 = MTP_TST_MSG_SLTA; |
| mng->length = l3_len - 2; |
| msgb_put(out, mng->length); |
| memcpy(mng->data, in_mng->data, mng->length); |
| |
| return out; |
| } |
| |
| static struct msgb *mtp_tfp_alloc(struct mtp_link *link, int apoc) |
| { |
| struct mtp_level_3_hdr *hdr; |
| struct mtp_level_3_prohib *prb; |
| struct msgb *out = mtp_msg_alloc(link); |
| |
| if (!out) |
| return NULL; |
| |
| hdr = (struct mtp_level_3_hdr *) out->l2h; |
| hdr->ser_ind = MTP_SI_MNT_SNM_MSG; |
| prb = (struct mtp_level_3_prohib *) msgb_put(out, sizeof(*prb)); |
| prb->cmn.h0 = MTP_PROHIBIT_MSG_GRP; |
| prb->cmn.h1 = MTP_PROHIBIT_MSG_SIG; |
| prb->apoc = MTP_MAKE_APOC(apoc); |
| return out; |
| } |
| |
| static struct msgb *mtp_tra_alloc(struct mtp_link *link) |
| { |
| struct mtp_level_3_hdr *hdr; |
| struct mtp_level_3_cmn *cmn; |
| struct msgb *out = mtp_msg_alloc(link); |
| |
| if (!out) |
| return NULL; |
| |
| hdr = (struct mtp_level_3_hdr *) out->l2h; |
| hdr->ser_ind = MTP_SI_MNT_SNM_MSG; |
| cmn = (struct mtp_level_3_cmn *) msgb_put(out, sizeof(*cmn)); |
| cmn->h0 = MTP_TRF_RESTR_MSG_GRP; |
| cmn->h1 = MTP_RESTR_MSG_ALLWED; |
| return out; |
| } |
| |
| static struct msgb *mtp_sccp_alloc_ssa(struct mtp_link *link, int sls) |
| { |
| struct sccp_data_unitdata *udt; |
| struct sccp_con_ctrl_prt_mgt *prt; |
| struct mtp_level_3_hdr *hdr; |
| uint8_t *data; |
| |
| |
| struct msgb *out = mtp_msg_alloc(link); |
| |
| if (!out) |
| return NULL; |
| |
| hdr = (struct mtp_level_3_hdr *) out->l2h; |
| hdr->ser_ind = MTP_SI_MNT_SCCP; |
| |
| /* this appears to be round robin or such.. */ |
| hdr->addr = MTP_ADDR(sls % 16, link->dpc, link->opc); |
| |
| /* generate the UDT message... libsccp does not offer formating yet */ |
| udt = (struct sccp_data_unitdata *) msgb_put(out, sizeof(*udt)); |
| udt->type = SCCP_MSG_TYPE_UDT; |
| udt->proto_class = SCCP_PROTOCOL_CLASS_0; |
| udt->variable_called = 3; |
| udt->variable_calling = 5; |
| udt->variable_data = 7; |
| |
| /* put the called and calling address. It is LV */ |
| data = msgb_put(out, 2 + 1); |
| data[0] = 2; |
| data[1] = 0x42; |
| data[2] = 0x1; |
| |
| data = msgb_put(out, 2 + 1); |
| data[0] = 2; |
| data[1] = 0x42; |
| data[2] = 0x1; |
| |
| data = msgb_put(out, 1); |
| data[0] = sizeof(*prt); |
| |
| prt = (struct sccp_con_ctrl_prt_mgt *) msgb_put(out, sizeof(*prt)); |
| prt->sst = SCCP_SSA; |
| prt->assn = 254; |
| prt->apoc = MTP_MAKE_APOC(link->opc); |
| prt->mul_ind = 0; |
| |
| return out; |
| } |
| |
| void mtp_link_init(void) |
| { |
| tall_mtp_ctx = talloc_named_const(NULL, 1, "mtp-link"); |
| } |
| |
| static void mtp_send_sltm(struct mtp_link *link) |
| { |
| struct msgb *msg; |
| |
| link->sltm_pending = 1; |
| msg = mtp_create_sltm(link); |
| if (!msg) { |
| LOGP(DINP, LOGL_ERROR, "Failed to allocate SLTM.\n"); |
| return; |
| } |
| |
| mtp_link_submit(link, msg); |
| } |
| |
| static void mtp_sltm_t1_timeout(void *_link) |
| { |
| struct mtp_link *link = (struct mtp_link *) _link; |
| |
| if (link->slta_misses == 0) { |
| LOGP(DINP, LOGL_ERROR, "No SLTM response. Retrying. Link: %p\n", link); |
| ++link->slta_misses; |
| mtp_send_sltm(link); |
| bsc_schedule_timer(&link->t1_timer, MTP_T1); |
| } else { |
| LOGP(DINP, LOGL_ERROR, "Two missing SLTAs. Restart link: %p\n", link); |
| link->sccp_up = 0; |
| link->running = 0; |
| bsc_del_timer(&link->t2_timer); |
| mtp_link_sccp_down(link); |
| mtp_link_restart(link); |
| } |
| } |
| |
| static void mtp_sltm_t2_timeout(void *_link) |
| { |
| struct mtp_link *link = (struct mtp_link *) _link; |
| |
| if (!link->running) { |
| LOGP(DINP, LOGL_INFO, "Not restarting SLTM timer on link: %p\n", link); |
| return; |
| } |
| |
| link->slta_misses = 0; |
| mtp_send_sltm(link); |
| |
| bsc_schedule_timer(&link->t1_timer, MTP_T1); |
| |
| if (link->sltm_once && link->was_up) |
| LOGP(DINP, LOGL_INFO, "Not sending SLTM again as configured.\n"); |
| else |
| bsc_schedule_timer(&link->t2_timer, MTP_T2); |
| } |
| |
| static void mtp_delayed_start(void *link) |
| { |
| mtp_sltm_t2_timeout(link); |
| } |
| |
| struct mtp_link *mtp_link_alloc(void) |
| { |
| struct mtp_link *link; |
| |
| link = talloc_zero(tall_mtp_ctx, struct mtp_link); |
| if (!link) |
| return NULL; |
| |
| link->ni = MTP_NI_NATION_NET; |
| link->t1_timer.data = link; |
| link->t1_timer.cb = mtp_sltm_t1_timeout; |
| link->t2_timer.data = link; |
| link->t2_timer.cb = mtp_sltm_t2_timeout; |
| link->delay_timer.data = link; |
| link->delay_timer.cb = mtp_delayed_start; |
| INIT_LLIST_HEAD(&link->pending_msgs); |
| return link; |
| } |
| |
| void mtp_link_stop(struct mtp_link *link) |
| { |
| bsc_del_timer(&link->t1_timer); |
| bsc_del_timer(&link->t2_timer); |
| bsc_del_timer(&link->delay_timer); |
| link->sccp_up = 0; |
| link->running = 0; |
| link->sltm_pending = 0; |
| |
| mtp_link_sccp_down(link); |
| } |
| |
| void mtp_link_reset(struct mtp_link *link) |
| { |
| mtp_link_stop(link); |
| link->running = 1; |
| bsc_schedule_timer(&link->delay_timer, START_DELAY); |
| } |
| |
| static int mtp_link_sign_msg(struct mtp_link *link, struct mtp_level_3_hdr *hdr, int l3_len) |
| { |
| struct msgb *msg; |
| struct mtp_level_3_cmn *cmn; |
| |
| if (hdr->ni != link->ni || l3_len < 1) { |
| LOGP(DINP, LOGL_ERROR, "Unhandled data (ni: %d len: %d)\n", |
| hdr->ni, l3_len); |
| return -1; |
| } |
| |
| cmn = (struct mtp_level_3_cmn *) &hdr->data[0]; |
| LOGP(DINP, LOGL_DEBUG, "reg msg: h0: 0x%x h1: 0x%x\n", |
| cmn->h0, cmn->h1); |
| |
| switch (cmn->h0) { |
| case MTP_TRF_RESTR_MSG_GRP: |
| switch (cmn->h1) { |
| case MTP_RESTR_MSG_ALLWED: |
| LOGP(DINP, LOGL_INFO, "Received Restart Allowed. SST should be next: %p\n", link); |
| link->sccp_up = 0; |
| mtp_link_sccp_down(link); |
| |
| msg = mtp_tfp_alloc(link, 0); |
| if (!msg) |
| return -1; |
| mtp_link_submit(link, msg); |
| |
| msg = mtp_tra_alloc(link); |
| if (!msg) |
| return -1; |
| |
| mtp_link_submit(link, msg); |
| return 0; |
| break; |
| } |
| break; |
| } |
| |
| LOGP(DINP, LOGL_ERROR, "Unknown message:%d/%d %s\n", cmn->h0, cmn->h1, hexdump(&hdr->data[0], l3_len)); |
| return -1; |
| } |
| |
| static int mtp_link_regular_msg(struct mtp_link *link, struct mtp_level_3_hdr *hdr, int l3_len) |
| { |
| struct msgb *out; |
| struct mtp_level_3_mng *mng; |
| |
| if (hdr->ni != link->ni || l3_len < 1) { |
| LOGP(DINP, LOGL_ERROR, "Unhandled data (ni: %d len: %d)\n", |
| hdr->ni, l3_len); |
| return -1; |
| } |
| |
| mng = (struct mtp_level_3_mng *) &hdr->data[0]; |
| LOGP(DINP, LOGL_DEBUG, "reg msg: h0: 0x%x h1: 0x%x\n", |
| mng->cmn.h0, mng->cmn.h1); |
| |
| switch (mng->cmn.h0) { |
| case MTP_TST_MSG_GRP: |
| switch (mng->cmn.h1) { |
| case MTP_TST_MSG_SLTM: |
| /* simply respond to the request... */ |
| out = mtp_create_slta(link, mng, l3_len); |
| if (!out) |
| return -1; |
| mtp_link_submit(link, out); |
| return 0; |
| break; |
| case MTP_TST_MSG_SLTA: |
| if (mng->length != 14) { |
| LOGP(DINP, LOGL_ERROR, "Wrongly sized SLTA: %u\n", mng->length); |
| return -1; |
| } |
| |
| if (l3_len != 16) { |
| LOGP(DINP, LOGL_ERROR, "Wrongly sized SLTA: %u\n", mng->length); |
| return -1; |
| } |
| |
| if (memcmp(mng->data, link->test_ptrn, sizeof(link->test_ptrn)) != 0) { |
| LOGP(DINP, LOGL_ERROR, "Wrong test pattern SLTA\n"); |
| return -1; |
| } |
| |
| /* we had a matching slta */ |
| bsc_del_timer(&link->t1_timer); |
| link->sltm_pending = 0; |
| mtp_link_slta_recv(link); |
| return 0; |
| break; |
| } |
| break; |
| } |
| |
| return -1; |
| } |
| |
| static int mtp_link_sccp_data(struct mtp_link *link, struct mtp_level_3_hdr *hdr, struct msgb *msg, int l3_len) |
| { |
| struct msgb *out; |
| struct sccp_con_ctrl_prt_mgt *prt; |
| |
| msg->l2h = &hdr->data[0]; |
| if (msgb_l2len(msg) != l3_len) { |
| LOGP(DINP, LOGL_ERROR, "Size is wrong after playing with the l2h header.\n"); |
| return -1; |
| } |
| |
| |
| if (link->sccp_up) { |
| mtp_link_forward_sccp(link, msg, MTP_LINK_SLS(hdr->addr)); |
| return 0; |
| } else { |
| struct sccp_parse_result sccp; |
| memset(&sccp, 0, sizeof(sccp)); |
| if (sccp_parse_header(msg, &sccp) != 0) { |
| LOGP(DINP, LOGL_ERROR, "Failed to parsed SCCP header.\n"); |
| return -1; |
| } |
| |
| if (sccp_determine_msg_type(msg) != SCCP_MSG_TYPE_UDT) { |
| LOGP(DINP, LOGL_ERROR, "Dropping sccp data: 0x%x\n", |
| sccp_determine_msg_type(msg)); |
| return -1; |
| } |
| |
| if (msgb_l3len(msg) != 5) { |
| LOGP(DINP, LOGL_ERROR, "SCCP UDT msg of unexpected size: %u\n", |
| msgb_l3len(msg)); |
| return -1; |
| } |
| |
| if (msg->l3h[0] != SCCP_SST) { |
| LOGP(DINP, LOGL_ERROR, "Expected SCCP SST but got 0x%x\n", |
| msg->l3h[0]); |
| return -1; |
| } |
| |
| prt = (struct sccp_con_ctrl_prt_mgt *) &msg->l3h[0]; |
| if (prt->assn != 254 || prt->apoc != MTP_MAKE_APOC(link->opc)) { |
| LOGP(DINP, LOGL_ERROR, "Unknown SSN/APOC assn: %u, apoc: %u/%u\n", |
| prt->assn, ntohs(prt->apoc), prt->apoc); |
| return -1; |
| } |
| |
| out = mtp_sccp_alloc_ssa(link, MTP_LINK_SLS(hdr->addr)); |
| if (!out) |
| return -1; |
| |
| link->sccp_up = 1; |
| link->was_up = 1; |
| LOGP(DINP, LOGL_INFO, "SCCP is established. %p\n", link); |
| mtp_link_submit(link, out); |
| } |
| return 0; |
| } |
| |
| int mtp_link_data(struct mtp_link *link, struct msgb *msg) |
| { |
| int rc = -1; |
| struct mtp_level_3_hdr *hdr; |
| int l3_len; |
| |
| if (!msg->l2h || msgb_l2len(msg) < sizeof(*hdr)) |
| return -1; |
| |
| if (!link->running) { |
| LOGP(DINP, LOGL_ERROR, "Link is not running. Call mtp_link_reset first: %p\n", link); |
| return -1; |
| } |
| |
| hdr = (struct mtp_level_3_hdr *) msg->l2h; |
| l3_len = msgb_l2len(msg) - sizeof(*hdr); |
| |
| switch (hdr->ser_ind) { |
| case MTP_SI_MNT_SNM_MSG: |
| rc = mtp_link_sign_msg(link, hdr, l3_len); |
| break; |
| case MTP_SI_MNT_REG_MSG: |
| rc = mtp_link_regular_msg(link, hdr, l3_len); |
| break; |
| case MTP_SI_MNT_SCCP: |
| rc = mtp_link_sccp_data(link, hdr, msg, l3_len); |
| break; |
| default: |
| fprintf(stderr, "Unhandled: %u\n", hdr->ser_ind); |
| break; |
| } |
| |
| return rc; |
| } |
| |
| int mtp_link_submit_sccp_data(struct mtp_link *link, int sls, const uint8_t *data, unsigned int length) |
| { |
| uint8_t *put_ptr; |
| struct mtp_level_3_hdr *hdr; |
| struct msgb *msg; |
| |
| if (!link->sccp_up) { |
| LOGP(DINP, LOGL_ERROR, "SCCP msg after TRA and before SSA. Dropping it.\n"); |
| return -1; |
| } |
| |
| msg = mtp_msg_alloc(link); |
| if (!msg) |
| return -1; |
| |
| hdr = (struct mtp_level_3_hdr *) msg->l2h; |
| hdr->ser_ind = MTP_SI_MNT_SCCP; |
| |
| hdr->addr = MTP_ADDR(sls % 16, link->dpc, link->opc); |
| |
| /* copy the raw sccp data */ |
| put_ptr = msgb_put(msg, length); |
| memcpy(put_ptr, data, length); |
| |
| mtp_link_submit(link, msg); |
| return 0; |
| } |