/* Directing individual GSUP messages to their respective handlers. */ /* * (C) 2019 by sysmocom - s.f.m.c. GmbH * All Rights Reserved * * Author: Neels Hofmeyr * * SPDX-License-Identifier: GPL-2.0-or-later * * 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 . */ #include #include #include #include static enum osmo_gsup_message_class gsup_client_mux_classify(struct gsup_client_mux *gcm, const struct osmo_gsup_message *gsup_msg) { if (gsup_msg->message_class) return gsup_msg->message_class; LOGP(DLGSUP, LOGL_DEBUG, "No explicit GSUP Message Class, trying to guess from message type %s\n", osmo_gsup_message_type_name(gsup_msg->message_type)); switch (gsup_msg->message_type) { case OSMO_GSUP_MSGT_PROC_SS_REQUEST: case OSMO_GSUP_MSGT_PROC_SS_RESULT: case OSMO_GSUP_MSGT_PROC_SS_ERROR: return OSMO_GSUP_MESSAGE_CLASS_USSD; /* GSM 04.11 code implementing MO SMS */ case OSMO_GSUP_MSGT_MO_FORWARD_SM_ERROR: case OSMO_GSUP_MSGT_MO_FORWARD_SM_RESULT: case OSMO_GSUP_MSGT_READY_FOR_SM_ERROR: case OSMO_GSUP_MSGT_READY_FOR_SM_RESULT: case OSMO_GSUP_MSGT_MT_FORWARD_SM_REQUEST: return OSMO_GSUP_MESSAGE_CLASS_SMS; default: return OSMO_GSUP_MESSAGE_CLASS_SUBSCRIBER_MANAGEMENT; } } /* Non-static for unit tests */ int gsup_client_mux_rx(struct osmo_gsup_client *gsup_client, struct msgb *msg) { struct gsup_client_mux *gcm = osmo_gsup_client_get_data(gsup_client); struct osmo_gsup_message gsup; enum osmo_gsup_message_class message_class; int rc; rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup); if (rc < 0) { LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: '%s' (%d) [ %s]\n", get_value_string(gsm48_gmm_cause_names, -rc), -rc, osmo_hexdump(msg->data, msg->len)); goto msgb_free_and_return; } if (!gsup.imsi[0]) { LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: missing IMSI\n"); if (OSMO_GSUP_IS_MSGT_REQUEST(gsup.message_type)) gsup_client_mux_tx_error_reply(gcm, &gsup, GMM_CAUSE_INV_MAND_INFO); rc = -GMM_CAUSE_INV_MAND_INFO; goto msgb_free_and_return; } message_class = gsup_client_mux_classify(gcm, &gsup); if (message_class <= OSMO_GSUP_MESSAGE_CLASS_UNSET || message_class >= ARRAY_SIZE(gcm->rx_cb)) { LOGP(DLGSUP, LOGL_ERROR, "Failed to classify GSUP message target\n"); rc = -EINVAL; goto msgb_free_and_return; } if (!gcm->rx_cb[message_class].func) { LOGP(DLGSUP, LOGL_ERROR, "No receiver set up for GSUP Message Class %s\n", osmo_gsup_message_class_name(message_class)); rc = -ENOTSUP; goto msgb_free_and_return; } rc = gcm->rx_cb[message_class].func(gcm, gcm->rx_cb[message_class].data, &gsup); msgb_free_and_return: msgb_free(msg); return rc; } /* Make it clear that struct gsup_client_mux should be talloc allocated, so that it can be used as talloc parent. */ struct gsup_client_mux *gsup_client_mux_alloc(void *talloc_ctx) { return talloc_zero(talloc_ctx, struct gsup_client_mux); } /* Start a GSUP client to serve this gsup_client_mux. */ int gsup_client_mux_start(struct gsup_client_mux *gcm, const char *gsup_server_addr_str, uint16_t gsup_server_port, struct ipaccess_unit *ipa_dev) { gcm->gsup_client = osmo_gsup_client_create2(gcm, ipa_dev, gsup_server_addr_str, gsup_server_port, &gsup_client_mux_rx, NULL); if (!gcm->gsup_client) return -ENOMEM; osmo_gsup_client_set_data(gcm->gsup_client, gcm); return 0; } int gsup_client_mux_tx(struct gsup_client_mux *gcm, const struct osmo_gsup_message *gsup_msg) { struct msgb *msg; int rc; if (!gcm || !gcm->gsup_client) { LOGP(DLGSUP, LOGL_ERROR, "GSUP link is down, cannot send GSUP message\n"); return -ENOTSUP; } msg = osmo_gsup_client_msgb_alloc(); rc = osmo_gsup_encode(msg, gsup_msg); if (rc < 0) { LOGP(DLGSUP, LOGL_ERROR, "Failed to encode GSUP message: '%s'\n", strerror(-rc)); return rc; } return osmo_gsup_client_send(gcm->gsup_client, msg); } /* Set GSUP source_name to our local IPA name */ void gsup_client_mux_tx_set_source(const struct gsup_client_mux *gcm, struct osmo_gsup_message *gsup_msg) { const char *local_msc_name; const struct ipaccess_unit *ipa_dev; if (!gcm) return; if (!gcm->gsup_client) return; ipa_dev = osmo_gsup_client_get_ipaccess_unit(gcm->gsup_client); if (!ipa_dev) return; local_msc_name = ipa_dev->serno; if (!local_msc_name) return; gsup_msg->source_name = (const uint8_t *) local_msc_name; gsup_msg->source_name_len = strlen(local_msc_name) + 1; } /* Transmit GSUP error in response to original message */ void gsup_client_mux_tx_error_reply(struct gsup_client_mux *gcm, const struct osmo_gsup_message *gsup_orig, enum gsm48_gmm_cause cause) { struct osmo_gsup_message gsup_reply; /* No need to answer if we couldn't parse an ERROR message type, only REQUESTs need an error reply. */ if (!OSMO_GSUP_IS_MSGT_REQUEST(gsup_orig->message_type)) return; gsup_reply = (struct osmo_gsup_message){ .cause = cause, .message_type = OSMO_GSUP_TO_MSGT_ERROR(gsup_orig->message_type), .message_class = gsup_orig->message_class, .destination_name = gsup_orig->source_name, .destination_name_len = gsup_orig->source_name_len, /* RP-Message-Reference is mandatory for SM Service */ .sm_rp_mr = gsup_orig->sm_rp_mr, }; OSMO_STRLCPY_ARRAY(gsup_reply.imsi, gsup_orig->imsi); gsup_client_mux_tx_set_source(gcm, &gsup_reply); /* For SS/USSD, it's important to keep both session state and ID IEs */ if (gsup_orig->session_state != OSMO_GSUP_SESSION_STATE_NONE) { gsup_reply.session_state = OSMO_GSUP_SESSION_STATE_END; gsup_reply.session_id = gsup_orig->session_id; } if (osmo_gsup_client_enc_send(gcm->gsup_client, &gsup_reply)) LOGP(DLGSUP, LOGL_ERROR, "Failed to send Error reply (imsi=%s)\n", osmo_quote_str(gsup_orig->imsi, -1)); }