diff options
Diffstat (limited to 'openbsc/src/libmgcp/osmux.c')
-rw-r--r-- | openbsc/src/libmgcp/osmux.c | 398 |
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 000000000..3fdc652b0 --- /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); +} |