174 lines
5.7 KiB
C
174 lines
5.7 KiB
C
/* Directing individual GSUP messages to their respective handlers. */
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/*
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* (C) 2019 by sysmocom - s.m.f.c. GmbH <info@sysmocom.de>
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* All Rights Reserved
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*
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* Author: Neels Hofmeyr
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <errno.h>
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#include <osmocom/gsupclient/gsup_client.h>
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#include <osmocom/msc/debug.h>
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#include <osmocom/msc/gsup_client_mux.h>
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static enum osmo_gsup_message_class gsup_client_mux_classify(struct gsup_client_mux *gcm,
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const struct osmo_gsup_message *gsup_msg)
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{
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if (gsup_msg->message_class)
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return gsup_msg->message_class;
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LOGP(DLGSUP, LOGL_DEBUG, "No explicit GSUP Message Class, trying to guess from message type %s\n",
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osmo_gsup_message_type_name(gsup_msg->message_type));
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switch (gsup_msg->message_type) {
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case OSMO_GSUP_MSGT_PROC_SS_REQUEST:
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case OSMO_GSUP_MSGT_PROC_SS_RESULT:
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case OSMO_GSUP_MSGT_PROC_SS_ERROR:
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return OSMO_GSUP_MESSAGE_CLASS_USSD;
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/* GSM 04.11 code implementing MO SMS */
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case OSMO_GSUP_MSGT_MO_FORWARD_SM_ERROR:
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case OSMO_GSUP_MSGT_MO_FORWARD_SM_RESULT:
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case OSMO_GSUP_MSGT_READY_FOR_SM_ERROR:
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case OSMO_GSUP_MSGT_READY_FOR_SM_RESULT:
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case OSMO_GSUP_MSGT_MT_FORWARD_SM_REQUEST:
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return OSMO_GSUP_MESSAGE_CLASS_SMS;
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default:
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return OSMO_GSUP_MESSAGE_CLASS_SUBSCRIBER_MANAGEMENT;
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}
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}
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/* Non-static for unit tests */
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int gsup_client_mux_rx(struct osmo_gsup_client *gsup_client, struct msgb *msg)
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{
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struct gsup_client_mux *gcm = gsup_client->data;
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struct osmo_gsup_message gsup;
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enum osmo_gsup_message_class message_class;
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int rc;
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rc = osmo_gsup_decode(msgb_l2(msg), msgb_l2len(msg), &gsup);
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if (rc < 0) {
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LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: '%s' (%d) [ %s]\n",
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get_value_string(gsm48_gmm_cause_names, -rc), -rc, osmo_hexdump(msg->data, msg->len));
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goto msgb_free_and_return;
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}
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if (!gsup.imsi[0]) {
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LOGP(DLGSUP, LOGL_ERROR, "Failed to decode GSUP message: missing IMSI\n");
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if (OSMO_GSUP_IS_MSGT_REQUEST(gsup.message_type))
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gsup_client_mux_tx_error_reply(gcm, &gsup, GMM_CAUSE_INV_MAND_INFO);
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rc = -GMM_CAUSE_INV_MAND_INFO;
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goto msgb_free_and_return;
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}
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message_class = gsup_client_mux_classify(gcm, &gsup);
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if (message_class <= OSMO_GSUP_MESSAGE_CLASS_UNSET || message_class >= ARRAY_SIZE(gcm->rx_cb)) {
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LOGP(DLGSUP, LOGL_ERROR, "Failed to classify GSUP message target\n");
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rc = -EINVAL;
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goto msgb_free_and_return;
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}
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if (!gcm->rx_cb[message_class].func) {
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LOGP(DLGSUP, LOGL_ERROR, "No receiver set up for GSUP Message Class %s\n", osmo_gsup_message_class_name(message_class));
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rc = -ENOTSUP;
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goto msgb_free_and_return;
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}
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rc = gcm->rx_cb[message_class].func(gcm, gcm->rx_cb[message_class].data, &gsup);
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msgb_free_and_return:
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msgb_free(msg);
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return rc;
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}
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/* Make it clear that struct gsup_client_mux should be talloc allocated, so that it can be used as talloc parent. */
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struct gsup_client_mux *gsup_client_mux_alloc(void *talloc_ctx)
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{
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return talloc_zero(talloc_ctx, struct gsup_client_mux);
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}
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/* Start a GSUP client to serve this gsup_client_mux. */
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int gsup_client_mux_start(struct gsup_client_mux *gcm, const char *gsup_server_addr_str, uint16_t gsup_server_port,
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struct ipaccess_unit *ipa_dev)
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{
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gcm->gsup_client = osmo_gsup_client_create2(gcm, ipa_dev,
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gsup_server_addr_str,
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gsup_server_port,
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&gsup_client_mux_rx, NULL);
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if (!gcm->gsup_client)
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return -ENOMEM;
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gcm->gsup_client->data = gcm;
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return 0;
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}
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int gsup_client_mux_tx(struct gsup_client_mux *gcm, const struct osmo_gsup_message *gsup_msg)
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{
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struct msgb *msg;
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int rc;
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if (!gcm || !gcm->gsup_client) {
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LOGP(DLGSUP, LOGL_ERROR, "GSUP link is down, cannot send GSUP message\n");
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return -ENOTSUP;
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}
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msg = osmo_gsup_client_msgb_alloc();
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rc = osmo_gsup_encode(msg, gsup_msg);
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if (rc < 0) {
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LOGP(DLGSUP, LOGL_ERROR, "Failed to encode GSUP message: '%s'\n", strerror(-rc));
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return rc;
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}
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return osmo_gsup_client_send(gcm->gsup_client, msg);
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}
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/* Transmit GSUP error in response to original message */
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void gsup_client_mux_tx_error_reply(struct gsup_client_mux *gcm, const struct osmo_gsup_message *gsup_orig,
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enum gsm48_gmm_cause cause)
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{
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struct osmo_gsup_message gsup_reply;
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/* No need to answer if we couldn't parse an ERROR message type, only REQUESTs need an error reply. */
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if (!OSMO_GSUP_IS_MSGT_REQUEST(gsup_orig->message_type))
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return;
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gsup_reply = (struct osmo_gsup_message){
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.cause = cause,
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.message_type = OSMO_GSUP_TO_MSGT_ERROR(gsup_orig->message_type),
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.message_class = gsup_orig->message_class,
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/* RP-Message-Reference is mandatory for SM Service */
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.sm_rp_mr = gsup_orig->sm_rp_mr,
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};
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OSMO_STRLCPY_ARRAY(gsup_reply.imsi, gsup_orig->imsi);
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/* For SS/USSD, it's important to keep both session state and ID IEs */
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if (gsup_orig->session_state != OSMO_GSUP_SESSION_STATE_NONE) {
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gsup_reply.session_state = OSMO_GSUP_SESSION_STATE_END;
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gsup_reply.session_id = gsup_orig->session_id;
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}
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if (osmo_gsup_client_enc_send(gcm->gsup_client, &gsup_reply))
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LOGP(DLGSUP, LOGL_ERROR, "Failed to send Error reply (imsi=%s)\n",
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osmo_quote_str(gsup_orig->imsi, -1));
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}
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