diff options
Diffstat (limited to 'src/libmsc/mncc_sock.c')
-rw-r--r-- | src/libmsc/mncc_sock.c | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/src/libmsc/mncc_sock.c b/src/libmsc/mncc_sock.c new file mode 100644 index 000000000..0efe3a156 --- /dev/null +++ b/src/libmsc/mncc_sock.c @@ -0,0 +1,318 @@ +/* mncc_sock.c: Tie the MNCC interface to a unix domain socket */ + +/* (C) 2008-2010 by Harald Welte <laforge@gnumonks.org> + * (C) 2009 by Andreas Eversberg <Andreas.Eversberg@versatel.de> + * (C) 2012 by Holger Hans Peter Freyther + * 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, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <assert.h> +#include <sys/socket.h> +#include <sys/un.h> + +#include <osmocom/core/talloc.h> +#include <osmocom/core/select.h> +#include <osmocom/core/socket.h> +#include <osmocom/gsm/protocol/gsm_04_08.h> + +#include <openbsc/debug.h> +#include <openbsc/mncc.h> +#include <openbsc/gsm_data.h> + +struct mncc_sock_state { + struct gsm_network *net; + struct osmo_fd listen_bfd; /* fd for listen socket */ + struct osmo_fd conn_bfd; /* fd for connection to lcr */ +}; + +/* input from CC code into mncc_sock */ +int mncc_sock_from_cc(struct gsm_network *net, struct msgb *msg) +{ + struct gsm_mncc *mncc_in = (struct gsm_mncc *) msgb_data(msg); + int msg_type = mncc_in->msg_type; + + /* Check if we currently have a MNCC handler connected */ + if (net->mncc_state->conn_bfd.fd < 0) { + LOGP(DMNCC, LOGL_ERROR, "mncc_sock receives %s for external CC app " + "but socket is gone\n", get_mncc_name(msg_type)); + if (!mncc_is_data_frame(msg_type)) { + /* release the request */ + struct gsm_mncc mncc_out; + memset(&mncc_out, 0, sizeof(mncc_out)); + mncc_out.callref = mncc_in->callref; + mncc_set_cause(&mncc_out, GSM48_CAUSE_LOC_PRN_S_LU, + GSM48_CC_CAUSE_TEMP_FAILURE); + mncc_tx_to_cc(net, MNCC_REL_REQ, &mncc_out); + } + /* free the original message */ + msgb_free(msg); + return -1; + } + + /* FIXME: check for some maximum queue depth? */ + + /* Actually enqueue the message and mark socket write need */ + msgb_enqueue(&net->upqueue, msg); + net->mncc_state->conn_bfd.when |= BSC_FD_WRITE; + return 0; +} + +static void mncc_sock_close(struct mncc_sock_state *state) +{ + struct osmo_fd *bfd = &state->conn_bfd; + + LOGP(DMNCC, LOGL_NOTICE, "MNCC Socket has LOST connection\n"); + + close(bfd->fd); + bfd->fd = -1; + osmo_fd_unregister(bfd); + + /* re-enable the generation of ACCEPT for new connections */ + state->listen_bfd.when |= BSC_FD_READ; + + /* release all exisitng calls */ + gsm0408_clear_all_trans(state->net, GSM48_PDISC_CC); + + /* flush the queue */ + while (!llist_empty(&state->net->upqueue)) { + struct msgb *msg = msgb_dequeue(&state->net->upqueue); + msgb_free(msg); + } +} + +static int mncc_sock_read(struct osmo_fd *bfd) +{ + struct mncc_sock_state *state = (struct mncc_sock_state *)bfd->data; + struct gsm_mncc *mncc_prim; + struct msgb *msg; + int rc; + + msg = msgb_alloc(sizeof(*mncc_prim)+256, "mncc_sock_rx"); + if (!msg) + return -ENOMEM; + + mncc_prim = (struct gsm_mncc *) msg->tail; + + rc = recv(bfd->fd, msg->tail, msgb_tailroom(msg), 0); + if (rc == 0) + goto close; + + if (rc < 0) { + if (errno == EAGAIN) + return 0; + goto close; + } + + rc = mncc_tx_to_cc(state->net, mncc_prim->msg_type, mncc_prim); + + /* as we always synchronously process the message in mncc_send() and + * its callbacks, we can free the message here. */ + msgb_free(msg); + + return rc; + +close: + msgb_free(msg); + mncc_sock_close(state); + return -1; +} + +static int mncc_sock_write(struct osmo_fd *bfd) +{ + struct mncc_sock_state *state = bfd->data; + struct gsm_network *net = state->net; + int rc; + + while (!llist_empty(&net->upqueue)) { + struct msgb *msg, *msg2; + struct gsm_mncc *mncc_prim; + + /* peek at the beginning of the queue */ + msg = llist_entry(net->upqueue.next, struct msgb, list); + mncc_prim = (struct gsm_mncc *)msg->data; + + bfd->when &= ~BSC_FD_WRITE; + + /* bug hunter 8-): maybe someone forgot msgb_put(...) ? */ + if (!msgb_length(msg)) { + LOGP(DMNCC, LOGL_ERROR, "message type (%d) with ZERO " + "bytes!\n", mncc_prim->msg_type); + goto dontsend; + } + + /* try to send it over the socket */ + rc = write(bfd->fd, msgb_data(msg), msgb_length(msg)); + if (rc == 0) + goto close; + if (rc < 0) { + if (errno == EAGAIN) { + bfd->when |= BSC_FD_WRITE; + break; + } + goto close; + } + +dontsend: + /* _after_ we send it, we can deueue */ + msg2 = msgb_dequeue(&net->upqueue); + assert(msg == msg2); + msgb_free(msg); + } + return 0; + +close: + mncc_sock_close(state); + + return -1; +} + +static int mncc_sock_cb(struct osmo_fd *bfd, unsigned int flags) +{ + int rc = 0; + + if (flags & BSC_FD_READ) + rc = mncc_sock_read(bfd); + if (rc < 0) + return rc; + + if (flags & BSC_FD_WRITE) + rc = mncc_sock_write(bfd); + + return rc; +} + +/** + * Send a version indication to the remote. + */ +static void queue_hello(struct mncc_sock_state *mncc) +{ + struct gsm_mncc_hello *hello; + struct msgb *msg; + + msg = msgb_alloc(512, "mncc hello"); + if (!msg) { + LOGP(DMNCC, LOGL_ERROR, "Failed to allocate hello.\n"); + mncc_sock_close(mncc); + return; + } + + hello = (struct gsm_mncc_hello *) msgb_put(msg, sizeof(*hello)); + hello->msg_type = MNCC_SOCKET_HELLO; + hello->version = MNCC_SOCK_VERSION; + hello->mncc_size = sizeof(struct gsm_mncc); + hello->data_frame_size = sizeof(struct gsm_data_frame); + hello->called_offset = offsetof(struct gsm_mncc, called); + hello->signal_offset = offsetof(struct gsm_mncc, signal); + hello->emergency_offset = offsetof(struct gsm_mncc, emergency); + hello->lchan_type_offset = offsetof(struct gsm_mncc, lchan_type); + + msgb_enqueue(&mncc->net->upqueue, msg); + mncc->conn_bfd.when |= BSC_FD_WRITE; +} + +/* accept a new connection */ +static int mncc_sock_accept(struct osmo_fd *bfd, unsigned int flags) +{ + struct mncc_sock_state *state = (struct mncc_sock_state *)bfd->data; + struct osmo_fd *conn_bfd = &state->conn_bfd; + struct sockaddr_un un_addr; + socklen_t len; + int rc; + + len = sizeof(un_addr); + rc = accept(bfd->fd, (struct sockaddr *) &un_addr, &len); + if (rc < 0) { + LOGP(DMNCC, LOGL_ERROR, "Failed to accept a new connection\n"); + return -1; + } + + if (conn_bfd->fd >= 0) { + LOGP(DMNCC, LOGL_NOTICE, "MNCC app connects but we already have " + "another active connection ?!?\n"); + /* We already have one MNCC app connected, this is all we support */ + state->listen_bfd.when &= ~BSC_FD_READ; + close(rc); + return 0; + } + + conn_bfd->fd = rc; + conn_bfd->when = BSC_FD_READ; + conn_bfd->cb = mncc_sock_cb; + conn_bfd->data = state; + + if (osmo_fd_register(conn_bfd) != 0) { + LOGP(DMNCC, LOGL_ERROR, "Failed to register new connection fd\n"); + close(conn_bfd->fd); + conn_bfd->fd = -1; + return -1; + } + + LOGP(DMNCC, LOGL_NOTICE, "MNCC Socket has connection with external " + "call control application\n"); + + queue_hello(state); + return 0; +} + + +int mncc_sock_init(struct gsm_network *net, const char *sock_path) +{ + struct mncc_sock_state *state; + struct osmo_fd *bfd; + int rc; + + state = talloc_zero(tall_bsc_ctx, struct mncc_sock_state); + if (!state) + return -ENOMEM; + + state->net = net; + state->conn_bfd.fd = -1; + + bfd = &state->listen_bfd; + + bfd->fd = osmo_sock_unix_init(SOCK_SEQPACKET, 0, sock_path, + OSMO_SOCK_F_BIND); + if (bfd->fd < 0) { + LOGP(DMNCC, LOGL_ERROR, "Could not create unix socket: %s: %s\n", + sock_path, strerror(errno)); + talloc_free(state); + return -1; + } + + bfd->when = BSC_FD_READ; + bfd->cb = mncc_sock_accept; + bfd->data = state; + + rc = osmo_fd_register(bfd); + if (rc < 0) { + LOGP(DMNCC, LOGL_ERROR, "Could not register listen fd: %d\n", rc); + close(bfd->fd); + talloc_free(state); + return rc; + } + + net->mncc_state = state; + + LOGP(DMNCC, LOGL_NOTICE, "MNCC socket at %s\n", sock_path); + return 0; +} |