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-rw-r--r--openbsc/src/libmgcp/mgcp_osmux.c527
1 files changed, 527 insertions, 0 deletions
diff --git a/openbsc/src/libmgcp/mgcp_osmux.c b/openbsc/src/libmgcp/mgcp_osmux.c
new file mode 100644
index 000000000..c57df005b
--- /dev/null
+++ b/openbsc/src/libmgcp/mgcp_osmux.c
@@ -0,0 +1,527 @@
+/*
+ * (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 <inttypes.h> /* for PRIu64 */
+#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;
+ struct in_addr rem_addr;
+ int rem_port;
+ int refcnt;
+};
+
+static void *osmux;
+
+static void osmux_deliver(struct msgb *batch_msg, void *data)
+{
+ struct osmux_handle *handle = data;
+ struct sockaddr_in out = {
+ .sin_family = AF_INET,
+ .sin_port = handle->rem_port,
+ };
+
+ memcpy(&out.sin_addr, &handle->rem_addr, sizeof(handle->rem_addr));
+ sendto(osmux_fd.fd, batch_msg->data, batch_msg->len, 0,
+ (struct sockaddr *)&out, sizeof(out));
+}
+
+static struct osmux_handle *
+osmux_handle_find_get(struct in_addr *addr, int rem_port)
+{
+ 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->rem_addr, addr, sizeof(struct in_addr)) == 0 &&
+ h->rem_port == rem_port) {
+ LOGP(DMGCP, LOGL_DEBUG, "using existing OSMUX handle "
+ "for addr=%s:%d\n",
+ inet_ntoa(*addr), ntohs(rem_port));
+ h->refcnt++;
+ return h;
+ }
+ }
+
+ return NULL;
+}
+
+static void osmux_handle_put(struct osmux_in_handle *in)
+{
+ struct osmux_handle *h;
+
+ /* Lookup for existing OSMUX handle for this destination address. */
+ llist_for_each_entry(h, &osmux_handle_list, head) {
+ if (h->in == in) {
+ if (--h->refcnt == 0) {
+ LOGP(DMGCP, LOGL_INFO,
+ "Releasing unused osmux handle for %s:%d\n",
+ inet_ntoa(h->rem_addr),
+ ntohs(h->rem_port));
+ LOGP(DMGCP, LOGL_INFO, "Stats: "
+ "input RTP msgs: %u bytes: %"PRIu64" "
+ "output osmux msgs: %u bytes: %"PRIu64"\n",
+ in->stats.input_rtp_msgs,
+ in->stats.input_rtp_bytes,
+ in->stats.output_osmux_msgs,
+ in->stats.output_osmux_bytes);
+ llist_del(&h->head);
+ osmux_xfrm_input_fini(h->in);
+ talloc_free(h);
+ }
+ return;
+ }
+ }
+ LOGP(DMGCP, LOGL_ERROR, "cannot find Osmux input handle %p\n", in);
+}
+
+static struct osmux_handle *
+osmux_handle_alloc(struct mgcp_config *cfg, struct in_addr *addr, int rem_port)
+{
+ struct osmux_handle *h;
+
+ h = talloc_zero(osmux, struct osmux_handle);
+ if (!h)
+ return NULL;
+ h->rem_addr = *addr;
+ h->rem_port = rem_port;
+ h->refcnt++;
+
+ h->in = talloc_zero(h, 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 = h;
+
+ llist_add(&h->head, &osmux_handle_list);
+
+ LOGP(DMGCP, LOGL_DEBUG, "created new OSMUX handle for addr=%s:%d\n",
+ inet_ntoa(*addr), ntohs(rem_port));
+
+ return h;
+}
+
+static struct osmux_in_handle *
+osmux_handle_lookup(struct mgcp_config *cfg, struct in_addr *addr, int rem_port)
+{
+ struct osmux_handle *h;
+
+ h = osmux_handle_find_get(addr, rem_port);
+ if (h != NULL)
+ return h->in;
+
+ h = osmux_handle_alloc(cfg, addr, rem_port);
+ if (h == NULL)
+ return NULL;
+
+ return h->in;
+}
+
+int osmux_xfrm_to_osmux(int type, char *buf, int rc, struct mgcp_endpoint *endp)
+{
+ int ret;
+ struct msgb *msg;
+
+ msg = msgb_alloc(4096, "RTP");
+ if (!msg)
+ return 0;
+
+ memcpy(msg->data, buf, rc);
+ msgb_put(msg, rc);
+
+ while ((ret = osmux_xfrm_input(endp->osmux.in, msg, endp->osmux.cid)) > 0) {
+ /* batch full, build and deliver it */
+ osmux_xfrm_input_deliver(endp->osmux.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->osmux.cid == cid && this->s_addr == from_addr->s_addr)
+ return tmp;
+ }
+
+ LOGP(DMGCP, LOGL_ERROR, "Cannot find endpoint with cid=%d\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;
+
+ msg = osmux_recv(ofd, &addr);
+ if (!msg)
+ return -1;
+
+ /* not any further processing dummy messages */
+ if (msg->data[0] == MGCP_DUMMY_LOAD)
+ goto out;
+
+ 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;
+ }
+ osmux_xfrm_output(osmuxh, &endp->osmux.out, &list);
+ osmux_tx_sched(&list, scheduled_tx_bts_cb, endp);
+ }
+out:
+ msgb_free(msg);
+ return 0;
+}
+
+/* This is called from the bsc-nat */
+static int osmux_handle_dummy(struct mgcp_config *cfg, struct sockaddr_in *addr,
+ struct msgb *msg)
+{
+ struct mgcp_endpoint *endp;
+ uint8_t osmux_cid;
+
+ if (msg->len < 1 + sizeof(osmux_cid)) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "Discarding truncated Osmux dummy load\n");
+ goto out;
+ }
+
+ LOGP(DMGCP, LOGL_DEBUG, "Received Osmux dummy load from %s\n",
+ inet_ntoa(addr->sin_addr));
+
+ if (!cfg->osmux) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "bsc wants to use Osmux but bsc-nat did not request it\n");
+ goto out;
+ }
+
+ /* extract the osmux CID from the dummy message */
+ memcpy(&osmux_cid, &msg->data[1], sizeof(osmux_cid));
+
+ endp = endpoint_lookup(cfg, osmux_cid, &addr->sin_addr, MGCP_DEST_BTS);
+ if (!endp) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "Cannot find endpoint for Osmux CID %d\n", osmux_cid);
+ goto out;
+ }
+
+ if (endp->osmux.state == OSMUX_STATE_ENABLED)
+ goto out;
+
+ if (osmux_enable_endpoint(endp, OSMUX_ROLE_BSC_NAT,
+ &addr->sin_addr, addr->sin_port) < 0 ){
+ LOGP(DMGCP, LOGL_ERROR,
+ "Could not enable osmux in endpoint %d\n",
+ ENDPOINT_NUMBER(endp));
+ goto out;
+ }
+
+ LOGP(DMGCP, LOGL_INFO, "Enabling osmux in endpoint %d for %s:%u\n",
+ ENDPOINT_NUMBER(endp), inet_ntoa(addr->sin_addr),
+ ntohs(addr->sin_port));
+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;
+
+ msg = osmux_recv(ofd, &addr);
+ if (!msg)
+ return -1;
+
+ /* not any further processing dummy messages */
+ if (msg->data[0] == MGCP_DUMMY_LOAD)
+ return osmux_handle_dummy(cfg, &addr, msg);
+
+ 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;
+ }
+ 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;
+
+ if (!cfg->osmux_port)
+ cfg->osmux_port = OSMUX_PORT;
+
+ ret = mgcp_create_bind("0.0.0.0", &osmux_fd, cfg->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,
+ struct in_addr *addr, uint16_t port)
+{
+ /* 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->osmux.cid), 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->osmux.state == OSMUX_STATE_DISABLED) {
+ LOGP(DMGCP, LOGL_ERROR, "Endpoint %u didn't request Osmux\n",
+ ENDPOINT_NUMBER(endp));
+ return -1;
+ }
+
+ osmux_xfrm_output_init(&endp->osmux.out,
+ (endp->osmux.cid * rtp_ssrc_winlen) +
+ (random() % rtp_ssrc_winlen));
+
+ endp->osmux.in = osmux_handle_lookup(endp->cfg, addr, port);
+ if (!endp->osmux.in) {
+ LOGP(DMGCP, LOGL_ERROR, "Cannot allocate input osmux handle\n");
+ return -1;
+ }
+
+ 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.state = OSMUX_STATE_ENABLED;
+
+ return 0;
+}
+
+void osmux_disable_endpoint(struct mgcp_endpoint *endp)
+{
+ LOGP(DMGCP, LOGL_INFO, "Releasing endpoint %u using Osmux CID %u\n",
+ ENDPOINT_NUMBER(endp), endp->osmux.cid);
+ endp->osmux.state = OSMUX_STATE_DISABLED;
+ endp->osmux.cid = -1;
+ osmux_handle_put(endp->osmux.in);
+}
+
+/* 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)
+{
+ char buf[1 + sizeof(uint8_t)];
+ struct in_addr addr_unset = {};
+
+ buf[0] = MGCP_DUMMY_LOAD;
+ memcpy(&buf[1], &endp->osmux.cid, sizeof(endp->osmux.cid));
+
+ /* Wait until we have the connection information from MDCX */
+ if (memcmp(&endp->net_end.addr, &addr_unset, sizeof(addr_unset)) == 0)
+ return 0;
+
+ if (endp->osmux.state == OSMUX_STATE_ACTIVATING) {
+ if (osmux_enable_endpoint(endp, OSMUX_ROLE_BSC,
+ &endp->net_end.addr,
+ htons(endp->cfg->osmux_port)) < 0) {
+ LOGP(DMGCP, LOGL_ERROR,
+ "Could not activate osmux in endpoint %d\n",
+ ENDPOINT_NUMBER(endp));
+ }
+ LOGP(DMGCP, LOGL_ERROR,
+ "Osmux CID %u for %s:%u is now enabled\n",
+ endp->osmux.cid, inet_ntoa(endp->net_end.addr),
+ endp->cfg->osmux_port);
+ }
+ LOGP(DMGCP, LOGL_DEBUG,
+ "sending OSMUX dummy load to %s CID %u\n",
+ inet_ntoa(endp->net_end.addr), endp->osmux.cid);
+
+ return mgcp_udp_send(osmux_fd.fd, &endp->net_end.addr,
+ htons(endp->cfg->osmux_port), buf, sizeof(buf));
+}
+
+/* bsc-nat allocates/releases the Osmux circuit ID */
+static uint8_t osmux_cid_bitmap[16];
+
+int osmux_get_cid(void)
+{
+ int i, j;
+
+ for (i = 0; i < sizeof(osmux_cid_bitmap) / 8; i++) {
+ for (j = 0; j < 8; j++) {
+ if (osmux_cid_bitmap[i] & (1 << j))
+ continue;
+
+ osmux_cid_bitmap[i] |= (1 << j);
+ LOGP(DMGCP, LOGL_DEBUG,
+ "Allocating Osmux CID %u from pool\n", (i * 8) + j);
+ return (i * 8) + j;
+ }
+ }
+
+ LOGP(DMGCP, LOGL_ERROR, "All Osmux circuits are in use!\n");
+ return -1;
+}
+
+void osmux_put_cid(uint8_t osmux_cid)
+{
+ LOGP(DMGCP, LOGL_DEBUG, "Osmux CID %u is back to the pool\n", osmux_cid);
+ osmux_cid_bitmap[osmux_cid / 8] &= ~(1 << (osmux_cid % 8));
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-20 02:24:57 +0000