| /* Copyright 2019 by sysmocom s.f.m.c. GmbH <info@sysmocom.de> |
| * |
| * All Rights Reserved |
| * |
| * 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, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <arpa/inet.h> |
| #include <netinet/in.h> |
| #include <netdb.h> |
| #include <stdbool.h> |
| #include <talloc.h> |
| #include <osmocom/core/utils.h> |
| #include <osmocom/core/select.h> |
| #include <osmocom/hlr/logging.h> |
| #include <osmocom/mslookup/mdns_sock.h> |
| |
| /*! Open socket to send and receive multicast data. |
| * |
| * The socket is opened with SO_REUSEADDR, so we can bind to the same IP and port multiple times. This socket receives |
| * everything sent to that multicast IP/port, including its own data data sent from osmo_mdns_sock_send(). So whenever |
| * sending something, the receive callback will be called with the same data and should discard it. |
| * |
| * \param[in] ip multicast IPv4 or IPv6 address. |
| * \param[in] port port number. |
| * \param[in] cb callback for incoming data that will be passed to osmo_fd_setup (should read from osmo_fd->fd). |
| * \param[in] data userdata passed to osmo_fd (available in cb as osmo_fd->data). |
| * \param[in] priv_nr additional userdata integer passed to osmo_fd (available in cb as osmo_fd->priv_nr). |
| * \returns allocated osmo_mdns_sock, NULL on error. |
| */ |
| struct osmo_mdns_sock *osmo_mdns_sock_init(void *ctx, const char *ip, unsigned int port, |
| int (*cb)(struct osmo_fd *fd, unsigned int what), |
| void *data, unsigned int priv_nr) |
| { |
| struct osmo_mdns_sock *ret; |
| int sock, rc; |
| struct addrinfo hints = {0}; |
| struct ip_mreq multicast_req = {0}; |
| in_addr_t iface = INADDR_ANY; |
| char portbuf[10]; |
| int y = 1; |
| |
| snprintf(portbuf, sizeof(portbuf) -1, "%u", port); |
| ret = talloc_zero(ctx, struct osmo_mdns_sock); |
| OSMO_ASSERT(ret); |
| |
| /* Fill addrinfo */ |
| hints.ai_family = PF_UNSPEC; |
| hints.ai_socktype = SOCK_DGRAM; |
| hints.ai_flags = (AI_PASSIVE | AI_NUMERICHOST); |
| rc = getaddrinfo(ip, portbuf, &hints, &ret->ai); |
| if (rc != 0) { |
| LOGP(DMSLOOKUP, LOGL_ERROR, "osmo_mdns_sock_init: getaddrinfo: %s\n", gai_strerror(rc)); |
| ret->ai = NULL; |
| goto error; |
| } |
| |
| /* Open socket */ |
| sock = socket(ret->ai->ai_family, ret->ai->ai_socktype, 0); |
| if (sock == -1) { |
| LOGP(DMSLOOKUP, LOGL_ERROR, "osmo_mdns_sock_init: socket: %s\n", strerror(errno)); |
| goto error; |
| } |
| |
| /* Set multicast options */ |
| rc = setsockopt(sock, IPPROTO_IP, IP_MULTICAST_IF, (char*)&iface, sizeof(iface)); |
| if (rc == -1) { |
| LOGP(DMSLOOKUP, LOGL_ERROR, "osmo_mdns_sock_init: setsockopt: %s\n", strerror(errno)); |
| goto error_sock; |
| } |
| memcpy(&multicast_req.imr_multiaddr, &((struct sockaddr_in*)(ret->ai->ai_addr))->sin_addr, |
| sizeof(multicast_req.imr_multiaddr)); |
| multicast_req.imr_interface.s_addr = htonl(INADDR_ANY); |
| rc = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&multicast_req, sizeof(multicast_req)); |
| if (rc == -1) { |
| LOGP(DMSLOOKUP, LOGL_ERROR, "osmo_mdns_sock_init: setsockopt: %s\n", strerror(errno)); |
| goto error_sock; |
| } |
| |
| /* Always allow binding the same IP and port twice. This is needed in OsmoHLR (where the code becomes cleaner by |
| * just using a different socket for server and client code) and in the mslookup_client_mdns_test. Also for |
| * osmo-mslookup-client if it is running multiple times in parallel (i.e. two incoming calls almost at the same |
| * time need to be resolved with the simple dialplan example that just starts new processes). */ |
| rc = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&y, sizeof(y)); |
| if (rc == -1) { |
| LOGP(DMSLOOKUP, LOGL_ERROR, "osmo_mdns_sock_init: setsockopt: %s\n", strerror(errno)); |
| goto error_sock; |
| } |
| |
| /* Bind and register osmo_fd callback */ |
| rc = bind(sock, ret->ai->ai_addr, ret->ai->ai_addrlen); |
| if (rc == -1) { |
| LOGP(DMSLOOKUP, LOGL_ERROR, "osmo_mdns_sock_init: bind: %s\n", strerror(errno)); |
| goto error_sock; |
| } |
| osmo_fd_setup(&ret->osmo_fd, sock, OSMO_FD_READ, cb, data, priv_nr); |
| if (osmo_fd_register(&ret->osmo_fd) != 0) |
| goto error_sock; |
| |
| return ret; |
| error_sock: |
| close(sock); |
| error: |
| if (ret->ai) |
| freeaddrinfo(ret->ai); |
| talloc_free(ret); |
| return NULL; |
| } |
| |
| /*! Send msgb over mdns_sock and consume msgb. |
| * \returns 0 on success, -1 on error. |
| */ |
| int osmo_mdns_sock_send(const struct osmo_mdns_sock *mdns_sock, struct msgb *msg) |
| { |
| size_t len = msgb_length(msg); |
| int rc = sendto(mdns_sock->osmo_fd.fd, msgb_data(msg), len, 0, mdns_sock->ai->ai_addr, |
| mdns_sock->ai->ai_addrlen); |
| msgb_free(msg); |
| return (rc == len) ? 0 : -1; |
| } |
| |
| /*! Tear down osmo_mdns_sock. */ |
| void osmo_mdns_sock_cleanup(struct osmo_mdns_sock *mdns_sock) |
| { |
| osmo_fd_close(&mdns_sock->osmo_fd); |
| freeaddrinfo(mdns_sock->ai); |
| talloc_free(mdns_sock); |
| } |