diff options
Diffstat (limited to 'src/libmsc/gsup_client_mux.c')
| -rw-r--r-- | src/libmsc/gsup_client_mux.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/src/libmsc/gsup_client_mux.c b/src/libmsc/gsup_client_mux.c new file mode 100644 index 000000000..7ec1712e7 --- /dev/null +++ b/src/libmsc/gsup_client_mux.c @@ -0,0 +1,163 @@ +/* Directing individual GSUP messages to their respective handlers. */ +/* + * (C) 2019 by sysmocom - s.m.f.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. + * + * 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 <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; + + OSMO_STRLCPY_ARRAY(gsup_reply.imsi, gsup_orig->imsi); + + gsup_reply = (struct osmo_gsup_message){ + .cause = cause, + .message_type = OSMO_GSUP_TO_MSGT_ERROR(gsup_orig->message_type), + }; + + 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)); +} |