235 lines
6.0 KiB
C
235 lines
6.0 KiB
C
/* Implementation of the C7 UDP link */
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/*
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* (C) 2010 by Holger Hans Peter Freyther <zecke@selfish.org>
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* (C) 2010 by On-Waves
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* All Rights Reserved
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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 <bsc_data.h>
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#include <udp_input.h>
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#include <mtp_data.h>
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#include <mtp_pcap.h>
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#include <snmp_mtp.h>
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#include <cellmgr_debug.h>
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#include <osmocore/talloc.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <string.h>
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#include <unistd.h>
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static int udp_write_cb(struct bsc_fd *fd, struct msgb *msg)
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{
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struct link_data *link;
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int rc;
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link = (struct link_data *) fd->data;
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LOGP(DINP, LOGL_DEBUG, "Sending MSU: %s\n", hexdump(msg->data, msg->len));
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if (link->pcap_fd >= 0)
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mtp_pcap_write_msu(link->pcap_fd, msg->l2h, msgb_l2len(msg));
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/* the assumption is we have connected the socket to the remote */
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rc = sendto(fd->fd, msg->data, msg->len, 0,
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(struct sockaddr *) &link->udp.remote, sizeof(link->udp.remote));
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if (rc != msg->len) {
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LOGP(DINP, LOGL_ERROR, "Failed to write msg to socket: %d\n", rc);
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return -1;
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}
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return 0;
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}
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static int udp_read_cb(struct bsc_fd *fd)
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{
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struct link_data *link;
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struct udp_data_hdr *hdr;
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struct msgb *msg;
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int rc;
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unsigned int length;
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msg = msgb_alloc_headroom(4096, 128, "UDP datagram");
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if (!msg) {
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LOGP(DINP, LOGL_ERROR, "Failed to allocate memory.\n");
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return -1;
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}
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link = (struct link_data *) fd->data;
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rc = read(fd->fd, msg->data, 2096);
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if (rc < sizeof(*hdr)) {
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LOGP(DINP, LOGL_ERROR, "Failed to read at least size of the header: %d\n", rc);
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rc = -1;
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goto exit;
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}
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/* throw away data as the link is down */
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if (link->the_link->available == 0) {
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LOGP(DINP, LOGL_ERROR, "The link is down. Not forwarding.\n");
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rc = 0;
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goto exit;
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}
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hdr = (struct udp_data_hdr *) msgb_put(msg, sizeof(*hdr));
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if (hdr->data_type == UDP_DATA_RETR_COMPL || hdr->data_type == UDP_DATA_RETR_IMPOS) {
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LOGP(DINP, LOGL_ERROR, "Link retrieval done. Restarting the link.\n");
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bsc_link_down(link);
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bsc_link_up(link);
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goto exit;
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} else if (hdr->data_type > UDP_DATA_MSU_PRIO_3) {
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LOGP(DINP, LOGL_ERROR, "Link failure. retrieved message.\n");
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bsc_link_down(link);
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goto exit;
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}
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length = ntohl(hdr->data_length);
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if (length + sizeof(*hdr) > (unsigned int) rc) {
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LOGP(DINP, LOGL_ERROR, "The MSU payload does not fit: %u + %u > %d \n",
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length, sizeof(*hdr), rc);
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rc = -1;
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goto exit;
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}
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msg->l2h = msgb_put(msg, length);
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LOGP(DINP, LOGL_DEBUG, "MSU data on: %p data %s.\n", link, hexdump(msg->data, msg->len));
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if (link->pcap_fd >= 0)
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mtp_pcap_write_msu(link->pcap_fd, msg->l2h, msgb_l2len(msg));
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mtp_link_data(link->the_link, msg);
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exit:
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msgb_free(msg);
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return rc;
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}
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static int udp_link_dummy(struct link_data *link)
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{
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/* nothing todo */
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return 0;
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}
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static void do_start(void *_data)
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{
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struct link_data *link = (struct link_data *) _data;
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link->forced_down = 0;
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snmp_mtp_activate(link->udp.session);
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bsc_link_up(link);
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}
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static int udp_link_reset(struct link_data *link)
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{
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LOGP(DINP, LOGL_NOTICE, "Will restart SLTM transmission in %d seconds.\n",
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link->udp.reset_timeout);
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snmp_mtp_deactivate(link->udp.session);
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bsc_link_down(link);
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/* restart the link in 90 seconds... to force a timeout on the BSC */
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link->link_activate.cb = do_start;
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link->link_activate.data = link;
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bsc_schedule_timer(&link->link_activate, link->udp.reset_timeout, 0);
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return 0;
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}
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static int udp_link_write(struct link_data *link, struct msgb *msg)
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{
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struct udp_data_hdr *hdr;
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hdr = (struct udp_data_hdr *) msgb_push(msg, sizeof(*hdr));
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hdr->format_type = UDP_FORMAT_SIMPLE_UDP;
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hdr->data_type = UDP_DATA_MSU_PRIO_0;
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hdr->data_link_index = htons(1);
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hdr->user_context = 0;
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hdr->data_length = htonl(msgb_l2len(msg));
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if (write_queue_enqueue(&link->udp.write_queue, msg) != 0) {
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LOGP(DINP, LOGL_ERROR, "Failed to enqueue msg.\n");
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msgb_free(msg);
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return -1;
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}
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return 0;
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}
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static int udp_link_start(struct link_data *link)
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{
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LOGP(DINP, LOGL_NOTICE, "UDP input is ready.\n");
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do_start(link);
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return 0;
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}
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int link_udp_init(struct link_data *link, int src_port, const char *remote, int remote_port)
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{
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struct sockaddr_in addr;
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int fd;
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int on;
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write_queue_init(&link->udp.write_queue, 100);
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/* function table */
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link->shutdown = udp_link_dummy;
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link->clear_queue = udp_link_dummy;
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link->reset = udp_link_reset;
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link->start = udp_link_start;
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link->write = udp_link_write;
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/* socket creation */
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link->udp.write_queue.bfd.data = link;
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link->udp.write_queue.bfd.when = BSC_FD_READ;
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link->udp.write_queue.read_cb = udp_read_cb;
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link->udp.write_queue.write_cb = udp_write_cb;
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link->udp.write_queue.bfd.fd = fd = socket(AF_INET, SOCK_DGRAM, 0);
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if (fd < 0) {
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LOGP(DINP, LOGL_ERROR, "Failed to create UDP socket.\n");
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return -1;
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}
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on = 1;
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setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
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memset(&addr, 0, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_port = htons(src_port);
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addr.sin_addr.s_addr = INADDR_ANY;
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if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
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perror("Failed to bind UDP socket");
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close(fd);
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return -1;
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}
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/* now connect the socket to the remote */
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memset(&link->udp.remote, 0, sizeof(link->udp.remote));
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link->udp.remote.sin_family = AF_INET;
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link->udp.remote.sin_port = htons(remote_port);
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inet_aton(remote, &link->udp.remote.sin_addr);
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if (bsc_register_fd(&link->udp.write_queue.bfd) != 0) {
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LOGP(DINP, LOGL_ERROR, "Failed to register BFD.\n");
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close(fd);
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return -1;
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}
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return 0;
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}
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