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-rw-r--r--openbsc/src/libmgcp/osmux.c398
1 files changed, 398 insertions, 0 deletions
diff --git a/openbsc/src/libmgcp/osmux.c b/openbsc/src/libmgcp/osmux.c
new file mode 100644
index 00000000..3fdc652b
--- /dev/null
+++ b/openbsc/src/libmgcp/osmux.c
@@ -0,0 +1,398 @@
+/*
+ * (C) 2012-2013 by Pablo Neira Ayuso <pablo@gnumonks.org>
+ * (C) 2012-2013 by On Waves ehf <http://www.on-waves.com>
+ * All rights not specifically granted under this license are reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by the
+ * Free Software Foundation; either version 3 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <stdio.h> /* for printf */
+#include <string.h> /* for memcpy */
+#include <stdlib.h> /* for abs */
+#include <netinet/in.h>
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/talloc.h>
+
+#include <osmocom/netif/osmux.h>
+#include <osmocom/netif/rtp.h>
+
+#include <openbsc/mgcp.h>
+#include <openbsc/mgcp_internal.h>
+#include <openbsc/osmux.h>
+
+#define OSMUX_PORT 1984
+
+static struct osmo_fd osmux_fd;
+
+static LLIST_HEAD(osmux_handle_list);
+
+struct osmux_handle {
+ struct llist_head head;
+ struct osmux_in_handle *in;
+};
+
+static void *osmux;
+
+static void osmux_deliver(struct msgb *batch_msg, void *data)
+{
+ struct in_addr *addr = data;
+ struct sockaddr_in out = {
+ .sin_family = AF_INET,
+ .sin_port = htons(OSMUX_PORT),
+ };
+ char buf[4096];
+
+ memcpy(&out.sin_addr, addr, sizeof(*addr));
+
+ osmux_snprintf(buf, sizeof(buf), batch_msg);
+ LOGP(DMGCP, LOGL_DEBUG, "OSMUX delivering batch to addr=%s: %s\n",
+ inet_ntoa(out.sin_addr), buf);
+
+ sendto(osmux_fd.fd, batch_msg->data, batch_msg->len, 0,
+ (struct sockaddr *)&out, sizeof(out));
+}
+
+static struct osmux_in_handle *
+osmux_handle_lookup(struct mgcp_config *cfg, struct in_addr *addr)
+{
+ struct osmux_handle *h;
+
+ /* Lookup for existing OSMUX handle for this destination address. */
+ llist_for_each_entry(h, &osmux_handle_list, head) {
+ if (memcmp(h->in->data, addr, sizeof(struct in_addr)) == 0) {
+ LOGP(DMGCP, LOGL_DEBUG, "using existing OSMUX handle "
+ "for addr=%s\n",
+ inet_ntoa(*addr));
+ goto out;
+ }
+ }
+
+ /* Does not exist, allocate it. */
+ h = talloc_zero(osmux, struct osmux_handle);
+ if (!h)
+ return NULL;
+
+ h->in = talloc_zero(osmux, struct osmux_in_handle);
+ if (!h->in) {
+ talloc_free(h);
+ return NULL;
+ }
+
+ h->in->osmux_seq = 0; /* sequence number to start OSmux message from */
+ h->in->batch_factor = cfg->osmux_batch;
+ h->in->deliver = osmux_deliver;
+ osmux_xfrm_input_init(h->in);
+ h->in->data = addr;
+
+ llist_add(&h->head, &osmux_handle_list);
+
+ LOGP(DMGCP, LOGL_DEBUG, "creating new OSMUX handle for addr=%s\n",
+ inet_ntoa(*addr));
+out:
+ return h->in;
+}
+
+int osmux_xfrm_to_osmux(int type, char *buf, int rc, struct mgcp_endpoint *endp)
+{
+ int ret;
+ struct msgb *msg;
+ struct in_addr *addr;
+ struct osmux_in_handle *in;
+
+ msg = msgb_alloc(4096, "RTP");
+ if (!msg)
+ return 0;
+
+ memcpy(msg->data, buf, rc);
+ msgb_put(msg, rc);
+
+ switch(type) {
+ case MGCP_DEST_NET:
+ addr = &endp->net_end.addr;
+ break;
+ case MGCP_DEST_BTS:
+ addr = &endp->bts_end.addr;
+ break;
+ default:
+ /* Should not ever happen */
+ LOGP(DMGCP, LOGL_ERROR, "Bad type %d. Fix your code.\n", type);
+ return 0;
+ }
+
+ /* Lookup for osmux input handle that munches this RTP frame */
+ in = osmux_handle_lookup(endp->cfg, addr);
+ if (!in) {
+ LOGP(DMGCP, LOGL_ERROR, "No osmux handle, aborting\n");
+ return 0;
+ }
+
+ LOGP(DMGCP, LOGL_DEBUG, "Osmux uses cid=%u from endpoint=%d (active=%d)\n",
+ endp->ci, ENDPOINT_NUMBER(endp), endp->allocated);
+
+ while ((ret = osmux_xfrm_input(in, msg, endp->ci)) > 0) {
+ /* batch full, build and deliver it */
+ osmux_xfrm_input_deliver(in);
+ }
+ return 0;
+}
+
+static struct mgcp_endpoint *
+endpoint_lookup(struct mgcp_config *cfg, int cid,
+ struct in_addr *from_addr, int type)
+{
+ struct mgcp_endpoint *tmp = NULL;
+ int i;
+
+ /* Lookup for the endpoint that corresponds to this port */
+ for (i=0; i<cfg->trunk.number_endpoints; i++) {
+ struct in_addr *this;
+
+ tmp = &cfg->trunk.endpoints[i];
+
+ if (!tmp->allocated)
+ continue;
+
+ switch(type) {
+ case MGCP_DEST_NET:
+ this = &tmp->net_end.addr;
+ break;
+ case MGCP_DEST_BTS:
+ this = &tmp->bts_end.addr;
+ break;
+ default:
+ /* Should not ever happen */
+ LOGP(DMGCP, LOGL_ERROR, "Bad type %d. Fix your code.\n", type);
+ return NULL;
+ }
+
+ if (tmp->ci == cid && this->s_addr == from_addr->s_addr)
+ return tmp;
+ }
+
+ LOGP(DMGCP, LOGL_ERROR, "Cannot find endpoint with cid=%d\n!\n", cid);
+
+ return NULL;
+}
+
+static void scheduled_tx_net_cb(struct msgb *msg, void *data)
+{
+ struct mgcp_endpoint *endp = data;
+ struct sockaddr_in addr;
+
+ mgcp_send(endp, MGCP_DEST_NET, 1, &addr, (char *)msg->data, msg->len);
+ msgb_free(msg);
+}
+
+static void scheduled_tx_bts_cb(struct msgb *msg, void *data)
+{
+ struct mgcp_endpoint *endp = data;
+ struct sockaddr_in addr;
+
+ mgcp_send(endp, MGCP_DEST_BTS, 1, &addr, (char *)msg->data, msg->len);
+ msgb_free(msg);
+}
+
+static struct msgb *osmux_recv(struct osmo_fd *ofd, struct sockaddr_in *addr)
+{
+ struct msgb *msg;
+ socklen_t slen = sizeof(*addr);
+ int ret;
+
+ msg = msgb_alloc(4096, "OSMUX");
+ if (!msg) {
+ LOGP(DMGCP, LOGL_ERROR, "cannot allocate message\n");
+ return NULL;
+ }
+ ret = recvfrom(ofd->fd, msg->data, msg->data_len, 0,
+ (struct sockaddr *)addr, &slen);
+ if (ret <= 0) {
+ msgb_free(msg);
+ LOGP(DMGCP, LOGL_ERROR, "cannot receive message\n");
+ return NULL;
+ }
+ msgb_put(msg, ret);
+
+ return msg;
+}
+
+int osmux_read_from_bsc_nat_cb(struct osmo_fd *ofd, unsigned int what)
+{
+ struct msgb *msg;
+ struct osmux_hdr *osmuxh;
+ struct llist_head list;
+ struct sockaddr_in addr;
+ struct mgcp_config *cfg = ofd->data;
+ char buf[4096];
+
+ msg = osmux_recv(ofd, &addr);
+ if (!msg)
+ return -1;
+
+ /* not any further processing dummy messages */
+ if (msg->data[0] == MGCP_DUMMY_LOAD)
+ goto out;
+
+ osmux_snprintf(buf, sizeof(buf), msg);
+ LOGP(DMGCP, LOGL_DEBUG, "received OSMUX message from "
+ "BSC NAT (len=%d) %s\n", msg->len, buf);
+
+ while((osmuxh = osmux_xfrm_output_pull(msg)) != NULL) {
+ struct mgcp_endpoint *endp;
+
+ /* Yes, we use MGCP_DEST_NET to locate the origin */
+ endp = endpoint_lookup(cfg, osmuxh->circuit_id,
+ &addr.sin_addr, MGCP_DEST_NET);
+ if (!endp) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "Cannot find an endpoint for circuit_id=%d\n",
+ osmuxh->circuit_id);
+ goto out;
+ }
+
+ LOGP(DMGCP, LOGL_DEBUG,
+ "sending extracted RTP from OSMUX to BSC via endpoint=%u "
+ "(allocated=%d)\n", ENDPOINT_NUMBER(endp), endp->allocated);
+
+ osmux_xfrm_output(osmuxh, &endp->osmux_out, &list);
+ osmux_tx_sched(&list, scheduled_tx_bts_cb, endp);
+ }
+out:
+ msgb_free(msg);
+ return 0;
+}
+
+int osmux_read_from_bsc_cb(struct osmo_fd *ofd, unsigned int what)
+{
+ struct msgb *msg;
+ struct osmux_hdr *osmuxh;
+ struct llist_head list;
+ struct sockaddr_in addr;
+ struct mgcp_config *cfg = ofd->data;
+ char buf[4096];
+
+ msg = osmux_recv(ofd, &addr);
+ if (!msg)
+ return -1;
+
+ /* not any further processing dummy messages */
+ if (msg->data[0] == MGCP_DUMMY_LOAD)
+ goto out;
+
+ osmux_snprintf(buf, sizeof(buf), msg);
+ LOGP(DMGCP, LOGL_DEBUG, "received OSMUX message "
+ "from BSC (len=%d) %s\n", msg->len, buf);
+
+ while((osmuxh = osmux_xfrm_output_pull(msg)) != NULL) {
+ struct mgcp_endpoint *endp;
+
+ /* Yes, we use MGCP_DEST_BTS to locate the origin */
+ endp = endpoint_lookup(cfg, osmuxh->circuit_id,
+ &addr.sin_addr, MGCP_DEST_BTS);
+ if (!endp) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "Cannot find an endpoint for circuit_id=%d\n",
+ osmuxh->circuit_id);
+ goto out;
+ }
+
+ LOGP(DMGCP, LOGL_DEBUG,
+ "sending extracted RTP from OSMUX to MSC via endpoint=%u "
+ "(allocated=%d)\n", ENDPOINT_NUMBER(endp), endp->allocated);
+
+ osmux_xfrm_output(osmuxh, &endp->osmux_out, &list);
+ osmux_tx_sched(&list, scheduled_tx_net_cb, endp);
+ }
+out:
+ msgb_free(msg);
+ return 0;
+}
+
+int osmux_init(int role, struct mgcp_config *cfg)
+{
+ int ret;
+
+ switch(role) {
+ case OSMUX_ROLE_BSC:
+ osmux_fd.cb = osmux_read_from_bsc_nat_cb;
+ break;
+ case OSMUX_ROLE_BSC_NAT:
+ osmux_fd.cb = osmux_read_from_bsc_cb;
+ break;
+ default:
+ LOGP(DMGCP, LOGL_ERROR, "wrong role for OSMUX\n");
+ return -1;
+ }
+ osmux_fd.data = cfg;
+
+ ret = mgcp_create_bind("0.0.0.0", &osmux_fd, OSMUX_PORT);
+ if (ret < 0) {
+ LOGP(DMGCP, LOGL_ERROR, "cannot bind OSMUX socket\n");
+ return ret;
+ }
+ osmux_fd.when |= BSC_FD_READ;
+
+ ret = osmo_fd_register(&osmux_fd);
+ if (ret < 0) {
+ LOGP(DMGCP, LOGL_ERROR, "cannot register OSMUX socket\n");
+ return ret;
+ }
+ cfg->osmux_init = 1;
+
+ return 0;
+}
+
+int osmux_enable_endpoint(struct mgcp_endpoint *endp, int role)
+{
+ /* If osmux is enabled, initialize the output handler. This handler is
+ * used to reconstruct the RTP flow from osmux. The RTP SSRC is
+ * allocated based on the circuit ID (endp->ci), which is unique in the
+ * local scope to the BSC/BSC-NAT. We use it to divide the RTP SSRC
+ * space (2^32) by the 256 possible circuit IDs, then randomly select
+ * one value from that window. Thus, we have no chance to have
+ * overlapping RTP SSRC traveling to the BTSes behind the BSC,
+ * similarly, for flows traveling to the MSC.
+ */
+ static const uint32_t rtp_ssrc_winlen = UINT32_MAX / 256;
+
+ if (!endp->cfg->osmux_init) {
+ if (osmux_init(role, endp->cfg) < 0) {
+ LOGP(DMGCP, LOGL_ERROR, "Cannot init OSMUX\n");
+ return -1;
+ }
+ LOGP(DMGCP, LOGL_NOTICE, "OSMUX requested, ENABLING.\n");
+ }
+
+ osmux_xfrm_output_init(&endp->osmux_out,
+ (endp->ci * rtp_ssrc_winlen) +
+ (random() % rtp_ssrc_winlen));
+
+ switch (endp->cfg->role) {
+ case MGCP_BSC_NAT:
+ endp->type = MGCP_OSMUX_BSC_NAT;
+ break;
+ case MGCP_BSC:
+ endp->type = MGCP_OSMUX_BSC;
+ break;
+ }
+ endp->osmux = 1;
+
+ return 0;
+}
+
+/* We don't need to send the dummy load for osmux so often as another endpoint
+ * may have already punched the hole in the firewall. This approach is simple
+ * though.
+ */
+int osmux_send_dummy(struct mgcp_endpoint *endp)
+{
+ static char buf[] = { MGCP_DUMMY_LOAD };
+
+ LOGP(DMGCP, LOGL_DEBUG, "sending OSMUX dummy load to %s\n",
+ inet_ntoa(endp->net_end.addr));
+
+ return mgcp_udp_send(osmux_fd.fd, &endp->net_end.addr,
+ htons(OSMUX_PORT), buf, 1);
+}