diff options
Diffstat (limited to 'src/sccp_scrc.c')
| -rw-r--r-- | src/sccp_scrc.c | 473 |
1 files changed, 473 insertions, 0 deletions
diff --git a/src/sccp_scrc.c b/src/sccp_scrc.c new file mode 100644 index 0000000..9bccc0a --- /dev/null +++ b/src/sccp_scrc.c @@ -0,0 +1,473 @@ +/* SCCP Routing Control (SCRC) according to ITU-T Q.714 */ + +/* (C) 2015-2017 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 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, see <http://www.gnu.org/licenses/>. + * + */ + +#include <stdbool.h> + +#include <osmocom/core/logging.h> +#include <osmocom/core/msgb.h> + +#include <sccp/sccp_types.h> +#include <osmocom/sigtran/osmo_ss7.h> +#include <osmocom/sigtran/sccp_sap.h> +#include <osmocom/sigtran/protocol/sua.h> +#include <osmocom/sigtran/protocol/mtp.h> + +#include "sccp_internal.h" +#include "xua_internal.h" + +/*********************************************************************** + * Helper Functions + ***********************************************************************/ + +static bool sua_is_connectionless(struct xua_msg *xua) +{ + if (xua->hdr.msg_class == SUA_MSGC_CL) + return true; + else + return false; +} + +static bool sua_is_cr(struct xua_msg *xua) +{ + if (xua->hdr.msg_class == SUA_MSGC_CO && + xua->hdr.msg_type == SUA_CO_CORE) + return true; + + return false; +} + +static bool dpc_accessible(struct osmo_sccp_instance *inst, uint32_t pc) +{ + /* TODO: implement this! */ + return true; +} + +static bool sccp_available(struct osmo_sccp_instance *inst, + const struct osmo_sccp_addr *addr) +{ + /* TODO: implement this! */ + return true; +} + +static int sua2sccp_tx_m3ua(struct osmo_sccp_instance *inst, + struct xua_msg *sua) +{ + struct msgb *msg; + struct osmo_mtp_prim *omp; + struct osmo_mtp_transfer_param *param; + struct osmo_ss7_instance *s7i = inst->ss7; + uint32_t remote_pc = sua->mtp.dpc; + + /* 1) encode the SUA in xua_msg to SCCP message */ + msg = osmo_sua_to_sccp(sua); + if (!msg) { + LOGP(DLSCCP, LOGL_ERROR, "Cannot encode SUA to SCCP\n"); + return -1; + } + + /* 2) wrap into MTP-TRANSFER.req primtiive */ + msg->l2h = msg->data; + omp = (struct osmo_mtp_prim *) msgb_push(msg, sizeof(*omp)); + osmo_prim_init(&omp->oph, MTP_SAP_USER, + OSMO_MTP_PRIM_TRANSFER, PRIM_OP_REQUEST, msg); + param = &omp->u.transfer; + if (sua->mtp.opc) + param->opc = sua->mtp.opc; + else + param->opc = s7i->cfg.primary_pc; + param->dpc = remote_pc; + param->sls = sua->mtp.sls; + param->sio = MTP_SIO(MTP_SI_SCCP, s7i->cfg.network_indicator); + + /* 3) send via MTP-SAP (osmo_ss7_instance) */ + return osmo_ss7_user_mtp_xfer_req(s7i, omp); +} + +/* Gererate MTP-TRANSFER.req from xUA message */ +static int gen_mtp_transfer_req_xua(struct osmo_sccp_instance *inst, + struct xua_msg *xua, + const struct osmo_sccp_addr *called) +{ + struct osmo_ss7_route *rt; + + /* this is a bit fishy due to the different requirements of + * classic SSCP/MTP compared to various SIGTRAN stackings. + * Normally, we would expect a fully encoded SCCP message here, + * but then if the route points to a SUA link, we actually need + * the SUA version of the message. + * + * We need to differentiate the following cases: + * a) SUA: encode XUA to SUA and send via ASP + * b) M3UA: encode XUA to SCCP, create MTP-TRANSFER.req + * primitive and send it via ASP + * c) M2UA/M2PA or CS7: encode XUA, create MTP-TRANSFER.req + * primitive and send it via link + */ + + if (called->presence & OSMO_SCCP_ADDR_T_PC) + xua->mtp.dpc = called->pc; + if (!xua->mtp.dpc) { + LOGP(DLSCCP, LOGL_ERROR, "MTP-TRANSFER.req from SCCP " + "without DPC?!?\n"); + return -1; + } + + rt = osmo_ss7_route_lookup(inst->ss7, xua->mtp.dpc); + if (!rt) { + LOGP(DLSCCP, LOGL_ERROR, "MTP-TRANSFER.req from SCCP for " + "DPC %u: no route!\n", xua->mtp.dpc); + return -1; + } + + if (rt->dest.as) { + struct osmo_ss7_as *as = rt->dest.as; + switch (as->cfg.proto) { + case OSMO_SS7_ASP_PROT_M3UA: + return sua2sccp_tx_m3ua(inst, xua); + default: + LOGP(DLSCCP, LOGL_ERROR, "MTP-TRANSFER.req for " + "unknown protocol %u\n", as->cfg.proto); + break; + } + } else if (rt->dest.linkset) { + LOGP(DLSCCP, LOGL_ERROR, "MTP-TRANSFER.req from SCCP for " + "linkset %s unsupported\n", rt->dest.linkset->cfg.name); + } else { + OSMO_ASSERT(0); + } + return -1; +} + +/*********************************************************************** + * Global Title Translation + ***********************************************************************/ + +static int translate(struct osmo_sccp_instance *inst, + const struct osmo_sccp_addr *called, + struct osmo_sccp_addr *translated) +{ + /* TODO: implement this! */ + *translated = *called; + return 0; +} + + +/*********************************************************************** + * Individual SCRC Nodes + ***********************************************************************/ + +static int scrc_local_out_common(struct osmo_sccp_instance *inst, + struct xua_msg *xua, + const struct osmo_sccp_addr *called); + +static int scrc_node_12(struct osmo_sccp_instance *inst, struct xua_msg *xua, + const struct osmo_sccp_addr *called) +{ + /* TODO: Determine restriction */ + /* TODO: Treat Calling Party Addr */ + /* TODO: Hop counter */ + /* MTP-TRANSFER.req to MTP */ + return gen_mtp_transfer_req_xua(inst, xua, called); +} + +static int scrc_node_2(struct osmo_sccp_instance *inst, struct xua_msg *xua, + const struct osmo_sccp_addr *called) +{ + /* Node 2 on Sheet 5, only CO */ + /* Is DPC accessible? */ + if (!dpc_accessible(inst, called->pc)) { + /* Error: MTP Failure */ + /* Routing Failure SCRC -> SCOC */ + sccp_scoc_rx_scrc_rout_fail(inst, xua, + SCCP_RETURN_CAUSE_MTP_FAILURE); + return 0; + } + /* Is SCCP available? */ + if (!sccp_available(inst, called)) { + /* Error: SCCP Failure */ + /* Routing Failure SCRC -> SCOC */ + sccp_scoc_rx_scrc_rout_fail(inst, xua, + SCCP_RETURN_CAUSE_SCCP_FAILURE); + return 0; + } + return scrc_node_12(inst, xua, called); +} + +static int scrc_node_7(struct osmo_sccp_instance *inst, + struct xua_msg *xua, + const struct osmo_sccp_addr *called) +{ + /* Connection Oriented? */ + if (sua_is_connectionless(xua)) { + /* TODO: Perform Capability Test */ + /* TODO: Canges Needed? */ + if (0) { + /* Changes Needed -> SCLC */ + return 0; + } + } else { + /* TODO: Coupling Required? */ + if (0) { + /* Node 13 (Sheet 5) */ + } + } + return scrc_node_12(inst, xua, called); +} + +/* Node 4 (Sheet 3) */ +static int scrc_node_4(struct osmo_sccp_instance *inst, + struct xua_msg *xua, uint32_t return_cause) +{ + /* TODO: Routing Failure SCRC -> OMAP */ + if (sua_is_connectionless(xua)) { + /* Routing Failure SCRC -> SCLC */ + sccp_sclc_rx_scrc_rout_fail(inst, xua, return_cause); + } else { + /* Routing Failure SCRC -> SCOC */ + sccp_scoc_rx_scrc_rout_fail(inst, xua, return_cause); + } + return 0; +} + +static int scrc_translate_node_9(struct osmo_sccp_instance *inst, + struct xua_msg *xua, + const struct osmo_sccp_addr *called) +{ + struct osmo_sccp_addr translated; + int rc; + + /* Translate */ + rc = translate(inst, called, &translated); + /* Node 9 (Sheet 3) */ + if (rc < 0) { + /* Node 4 (Sheet 3) */ + return scrc_node_4(inst, xua, + SCCP_RETURN_CAUSE_NO_TRANSLATION); + } + /* Route on SSN? */ + if (translated.ri != OSMO_SCCP_RI_SSN_PC && + translated.ri != OSMO_SCCP_RI_SSN_IP) { + /* TODO: GT Routing */ + /* Node 7 (Sheet 5) */ + return scrc_node_7(inst, xua, called); + } + + /* Check DPC resultant from GT translation */ + if (osmo_ss7_pc_is_local(inst->ss7, translated.pc)) { + if (sua_is_connectionless(xua)) { + /* CL_MSG -> SCLC */ + sccp_sclc_rx_from_scrc(inst, xua); + } else { + /* Node 1 (Sheet 3) */ + /* CO_MSG -> SCOC */ + sccp_scoc_rx_from_scrc(inst, xua); + } + return 0; + } else { + /* Availability already checked */ + /* Node 7 (Sheet 5) */ + return scrc_node_7(inst, xua, called); + } +} + +/* Node 6 (Sheet 3) */ +static int scrc_node_6(struct osmo_sccp_instance *inst, + struct xua_msg *xua, + const struct osmo_sccp_addr *called) +{ + struct osmo_sccp_user *scu; + + scu = sccp_user_find(inst, called->ssn, called->pc); + + /* Is subsystem equipped? */ + if (!scu) { + /* Error: unequipped user */ + return scrc_node_4(inst, xua, + SCCP_RETURN_CAUSE_UNEQUIPPED_USER); + } + /* Is subsystem available? */ + if (0 /* !subsys_available(scu) */) { + /* Error: subsystem failure */ + /* TODO: SCRC -> SSPC */ + if (sua_is_connectionless(xua)) { + /* Routing Failure SCRC -> SCLC */ + sccp_sclc_rx_scrc_rout_fail(inst, xua, + SCCP_RETURN_CAUSE_SUBSYSTEM_FAILURE); + } else { + /* Routing Failure SCRC -> SCOC */ + sccp_scoc_rx_scrc_rout_fail(inst, xua, + SCCP_RETURN_CAUSE_SUBSYSTEM_FAILURE); + } + return 0; + } + if (sua_is_connectionless(xua)) { + /* CL_MSG -> SCLC */ + sccp_sclc_rx_from_scrc(inst, xua); + } else { + /* Node 1 (Sheet 3) */ + /* CO_MSG -> SCOC */ + sccp_scoc_rx_from_scrc(inst, xua); + } + return 0; +} + +static int scrc_local_out_common(struct osmo_sccp_instance *inst, + struct xua_msg *xua, + const struct osmo_sccp_addr *called) +{ + struct osmo_ss7_instance *s7i = inst->ss7; + + /* Called address includes DPC? */ + if (called->presence & OSMO_SCCP_ADDR_T_PC) { + if (!osmo_ss7_pc_is_local(s7i, called->pc)) { + /* Node 7 of sheet 5 */ + /* Coupling required: no */ + return scrc_node_12(inst, xua, called); + } + /* Called address includes SSN? */ + if (called->presence & OSMO_SCCP_ADDR_T_SSN) { + if (translate && + (called->presence & OSMO_SCCP_ADDR_T_GT)) + return scrc_translate_node_9(inst, xua, called); + else + return scrc_node_6(inst, xua, called); + } + } + /* No SSN in CalledAddr or no DPC included */ + if (!(called->presence & OSMO_SCCP_ADDR_T_GT)) { + /* Error reason: Unqualified */ + /* TODO: Routing Failure SCRC -> OMAP */ + /* Node 4 (Sheet 3) */ + return scrc_node_4(inst, xua, + SCCP_RETURN_CAUSE_UNQUALIFIED); + } else + return scrc_translate_node_9(inst, xua, called); +} + +/*********************************************************************** + * Entrance points from MTP, SCLC, SCOC, ... + ***********************************************************************/ + +/* Figure C.1/Q.714 - SCCP Routing control procedures (SCRC) */ + +/* Connection oriented message SCOC -> SCRC */ +int sccp_scrc_rx_scoc_conn_msg(struct osmo_sccp_instance *inst, + struct xua_msg *xua) +{ + struct osmo_sccp_addr called; + + LOGP(DLSS7, LOGL_DEBUG, "%s: %s\n", __func__, xua_msg_dump(xua, &xua_dialect_sua)); + + sua_addr_parse(&called, xua, SUA_IEI_DEST_ADDR); + + /* Is this a CR message ? */ + if (xua->hdr.msg_type != SUA_CO_CORE) + return scrc_node_2(inst, xua, &called); + + /* TOOD: Coupling performed (not supported) */ + if (0) + return scrc_node_2(inst, xua, &called); + + return scrc_local_out_common(inst, xua, &called); +} + +/* Connectionless Message SCLC -> SCRC */ +int sccp_scrc_rx_sclc_msg(struct osmo_sccp_instance *inst, + struct xua_msg *xua) +{ + struct osmo_sccp_addr called; + + LOGP(DLSS7, LOGL_DEBUG, "%s: %s\n", __func__, xua_msg_dump(xua, &xua_dialect_sua)); + + sua_addr_parse(&called, xua, SUA_IEI_DEST_ADDR); + + /* Message Type */ + if (xua->hdr.msg_type == SUA_CL_CLDR) { + /* UDTS, XUDTS or LUDTS */ + if (called.ri != OSMO_SCCP_RI_GT) + return scrc_node_7(inst, xua, &called); + /* Fall-through */ + } else { + if (0 /* TODO: translation already performed */) { + /* Node 12 (Sheet 5) */ + return scrc_node_12(inst, xua, &called); + } + } + return scrc_local_out_common(inst, xua, &called); +} + +/* Figure C.1/Q.714 Sheet 1 of 12, after we converted the + * MTP-TRANSFER.ind to SUA */ +int scrc_rx_mtp_xfer_ind_xua(struct osmo_sccp_instance *inst, + struct xua_msg *xua) +{ + struct osmo_sccp_addr called; + uint32_t proto_class; + struct xua_msg_part *hop_ctr_part; + + LOGP(DLSS7, LOGL_DEBUG, "%s: %s\n", __func__, xua_msg_dump(xua, &xua_dialect_sua)); + /* TODO: SCCP or nodal congestion? */ + + /* CR or CL message? */ + if (!sua_is_connectionless(xua) && !sua_is_cr(xua)) { + /* Node 1 (Sheet 3) */ + /* deliver to SCOC */ + sccp_scoc_rx_from_scrc(inst, xua); + return 0; + } + /* We only treat connectionless and CR below */ + + sua_addr_parse(&called, xua, SUA_IEI_DEST_ADDR); + + /* Route on GT? */ + if (called.ri != OSMO_SCCP_RI_GT) { + /* Node 6 (Sheet 3) */ + return scrc_node_6(inst, xua, &called); + } + /* Message with hop-counter? */ + hop_ctr_part = xua_msg_find_tag(xua, SUA_IEI_S7_HOP_CTR); + if (hop_ctr_part) { + uint32_t hop_counter = xua_msg_part_get_u32(hop_ctr_part); + if (hop_counter <= 1) { + /* Error: hop-counter violation */ + /* node 4 */ + return scrc_node_4(inst, xua, + SCCP_RETURN_CAUSE_HOP_COUNTER_VIOLATION); + } + /* Decrement hop-counter */ + hop_counter--; + *(uint32_t *)hop_ctr_part->dat = htonl(hop_counter); + } + + /* node 3 (Sheet 2) */ + /* Protocol class 0? */ + proto_class = xua_msg_get_u32(xua, SUA_IEI_PROTO_CLASS); + switch (proto_class) { + case 0: + /* TODO: Assign SLS */ + break; + case 1: + /* TODO: Map incoming SLS to outgoing SLS */ + break; + default: + break; + } + return scrc_translate_node_9(inst, xua, &called); +} |