274 lines
7.3 KiB
C
274 lines
7.3 KiB
C
/* (C) 2019 by Harald Welte <laforge@gnumonks.org>
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* All Rights Reserved
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*
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* SPDX-License-Identifier: AGPL-3.0+
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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 Affero General Public License as published by
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* the Free Software Foundation; either version 3 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 Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include <errno.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <osmocom/core/talloc.h>
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#include <osmocom/core/select.h>
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#include <osmocom/core/socket.h>
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#include <osmocom/core/msgb.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/gsm/cbsp.h>
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#include <osmocom/gsm/protocol/gsm_48_049.h>
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#include <osmocom/netif/stream.h>
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#include "internal.h"
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#include "cbsp_server.h"
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#if 0
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struct osmo_cbsp_bsc {
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/* libosmo-netif stream client */
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struct osmo_stream_cli *stream;
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};
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#endif
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/*! Read one CBSP message from socket fd or store part if still not fully received.
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* \param[in] fd The fd for the socket to read from.
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* \param[out] rmsg internally allocated msgb containing a fully received CBSP message.
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* \param[inout] tmp_msg internally allocated msgb caching data for not yet fully received message.
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*
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* Function is designed just like ipa_msg_recv_buffered()
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*/
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int osmo_cbsp_recv_buffered(int fd, struct msgb **rmsg, struct msgb **tmp_msg)
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{
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struct msgb *msg = tmp_msg ? *tmp_msg : NULL;
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struct cbsp_header *h;
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int len, rc;
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int needed;
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if (!msg) {
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msg = osmo_cbsp_msgb_alloc(__func__);
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if (!msg) {
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return -ENOMEM;
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goto discard_msg;
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}
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msg->l1h = msg->tail;
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}
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if (msg->l2h == NULL) {
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/* first read the [missing part of the] header */
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needed = sizeof(*h) - msg->len;
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rc = recv(fd, msg->tail, needed, 0);
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if (rc == 0)
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goto discard_msg;
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else if (rc < 0) {
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if (errno == EAGAIN || errno == EINTR)
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rc = 0;
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else {
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rc = -errno;
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goto discard_msg;
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}
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}
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msgb_put(msg, rc);
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if (rc < needed) {
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if (msg->len == 0) {
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rc = -EAGAIN;
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goto discard_msg;
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}
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if (!tmp_msg) {
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rc = -EIO;
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goto discard_msg;
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}
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*tmp_msg = msg;
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return -EAGAIN;
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}
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msg->l2h = msg->tail;
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}
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h = (struct cbsp_header *) msg->data;
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/* then read the length as specified in the header */
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len = h->len[0] << 16 | h->len[1] << 8 | h->len[2];
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needed = len - msgb_l2len(msg);
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if (needed > 0) {
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rc = recv(fd, msg->tail, needed, 0);
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if (rc == 0)
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goto discard_msg;
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else if (rc < 0) {
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if (errno == EAGAIN || errno == EINTR)
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rc = 0;
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else {
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rc = -errno;
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goto discard_msg;
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}
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}
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msgb_put(msg, rc);
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/* still not all of payload received? */
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if (rc < needed) {
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if (!tmp_msg) {
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rc = -EIO;
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goto discard_msg;
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}
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*tmp_msg = msg;
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return -EAGAIN;
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}
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}
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/* else: complete message received */
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rc = msgb_l2len(msg);
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if (rc == 0) {
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/* drop empty message */
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rc = -EAGAIN;
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goto discard_msg;
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}
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if (tmp_msg)
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*tmp_msg = NULL;
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*rmsg = msg;
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return rc;
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discard_msg:
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if (tmp_msg)
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*tmp_msg = NULL;
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msgb_free(msg);
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return rc;
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}
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const char *cbsp_cbc_client_name(const struct osmo_cbsp_cbc_client *client)
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{
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struct osmo_fd *ofd = osmo_stream_srv_get_ofd(client->conn);
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return osmo_sock_get_name2(ofd->fd);
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}
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/* data from BSC has arrived at CBC */
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static int cbsp_cbc_read_cb(struct osmo_stream_srv *conn)
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{
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struct osmo_stream_srv_link *link = osmo_stream_srv_get_master(conn);
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struct osmo_cbsp_cbc_client *client = osmo_stream_srv_get_data(conn);
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struct osmo_cbsp_cbc *cbc = osmo_stream_srv_link_get_data(link);
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struct osmo_fd *ofd = osmo_stream_srv_get_ofd(conn);
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struct osmo_cbsp_decoded *decoded;
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struct msgb *msg = NULL;
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int rc;
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LOGPCC(client, LOGL_DEBUG, "read_cb rx_msg=%p\n", client->rx_msg);
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/* message de-segmentation */
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rc = osmo_cbsp_recv_buffered(ofd->fd, &msg, &client->rx_msg);
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if (rc <= 0) {
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if (rc == -EAGAIN || rc == -EINTR) {
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/* more data needs to be read */
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return 0;
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} else if (rc == -EPIPE || rc == -ECONNRESET) {
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/* lost connection with server */
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} else if (rc == 0) {
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/* connection closed with server */
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}
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/* destroy connection */
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osmo_stream_srv_destroy(conn);
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return -EBADF;
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}
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OSMO_ASSERT(msg);
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LOGPCC(client, LOGL_DEBUG, "Received CBSP %s\n", msgb_hexdump(msg));
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/* decode + dispatch message */
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decoded = osmo_cbsp_decode(client, msg);
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if (decoded) {
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LOGPCC(client, LOGL_INFO, "Received CBSP %s\n",
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get_value_string(cbsp_msg_type_names, decoded->msg_type));
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cbc->rx_cb(client, decoded);
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} else {
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LOGPCC(client, LOGL_ERROR, "Unable to decode %s\n", msgb_hexdump(msg));
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}
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msgb_free(msg);
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return 0;
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}
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/* connection from BSC to CBC has been closed */
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static int cbsp_cbc_closed_cb(struct osmo_stream_srv *conn)
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{
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struct osmo_cbsp_cbc_client *client = osmo_stream_srv_get_data(conn);
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LOGPCC(client, LOGL_INFO, "connection closed\n");
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llist_del(&client->list);
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talloc_free(client);
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return 0;
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}
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/* new connection from BSC has arrived at CBC */
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static int cbsp_cbc_accept_cb(struct osmo_stream_srv_link *link, int fd)
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{
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struct osmo_cbsp_cbc *cbc = osmo_stream_srv_link_get_data(link);
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struct osmo_cbsp_cbc_client *client = talloc_zero(cbc, struct osmo_cbsp_cbc_client);
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OSMO_ASSERT(client);
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client->conn = osmo_stream_srv_create(link, link, fd, cbsp_cbc_read_cb, cbsp_cbc_closed_cb, client);
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if (!client->conn) {
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LOGP(DCBSP, LOGL_ERROR, "Unable to create stream server for %s\n",
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osmo_sock_get_name2(fd));
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talloc_free(client);
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return -1;
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}
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client->fi = osmo_fsm_inst_alloc(&cbsp_server_fsm, client, client, LOGL_DEBUG, NULL);
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if (!client->fi) {
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LOGPCC(client, LOGL_ERROR, "Unable to allocate FSM\n");
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osmo_stream_srv_destroy(client->conn);
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talloc_free(client);
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return -1;
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}
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LOGPCC(client, LOGL_INFO, "New CBSP client connection\n");
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llist_add_tail(&client->list, &cbc->clients);
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return 0;
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}
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void cbsp_cbc_client_tx(struct osmo_cbsp_cbc_client *client, struct osmo_cbsp_decoded *cbsp)
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{
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struct msgb *msg = osmo_cbsp_encode(cbsp);
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LOGPCC(client, LOGL_INFO, "Transmitting %s\n",
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get_value_string(cbsp_msg_type_names, cbsp->msg_type));
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if (!msg) {
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LOGPCC(client, LOGL_ERROR, "Failed to encode CBSP %s\n",
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get_value_string(cbsp_msg_type_names, cbsp->msg_type));
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talloc_free(cbsp);
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return;
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}
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talloc_free(cbsp);
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osmo_stream_srv_send(client->conn, msg);
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}
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/* initialize the CBC-side CBSP server */
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struct osmo_cbsp_cbc *cbsp_cbc_create(void *ctx, int (*rx_cb)(struct osmo_cbsp_cbc_client *client,
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struct osmo_cbsp_decoded *dec))
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{
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struct osmo_cbsp_cbc *cbc = talloc_zero(ctx, struct osmo_cbsp_cbc);
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int rc;
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OSMO_ASSERT(cbc);
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cbc->rx_cb = rx_cb;
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INIT_LLIST_HEAD(&cbc->clients);
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cbc->link = osmo_stream_srv_link_create(cbc);
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osmo_stream_srv_link_set_data(cbc->link, cbc);
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osmo_stream_srv_link_set_nodelay(cbc->link, true);
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osmo_stream_srv_link_set_port(cbc->link, CBSP_TCP_PORT);
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osmo_stream_srv_link_set_accept_cb(cbc->link, cbsp_cbc_accept_cb);
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rc = osmo_stream_srv_link_open(cbc->link);
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OSMO_ASSERT(rc == 0);
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LOGP(DCBSP, LOGL_NOTICE, "Listening for CBSP at %s\n",
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osmo_stream_srv_link_get_sockname(cbc->link));
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return cbc;
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}
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