| /* Directing individual GSUP messages to their respective handlers. */ |
| /* |
| * (C) 2019 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> |
| * All Rights Reserved |
| * |
| * Author: Neels Hofmeyr |
| * |
| * SPDX-License-Identifier: GPL-2.0+ |
| * |
| * 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. |
| */ |
| #include <errno.h> |
| |
| #include <osmocom/gsupclient/gsup_client.h> |
| |
| #include <osmocom/msc/debug.h> |
| #include <osmocom/msc/gsup_client_mux.h> |
| |
| 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 = gsup_client->data; |
| 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; |
| gcm->gsup_client->data = 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); |
| } |
| |
| /* 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, |
| |
| /* 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); |
| |
| /* 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)); |
| } |