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#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <osmocom/core/socket.h>
#include <osmocom/core/select.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <talloc.h>
#include <unistd.h>
#include <virtphy/osmo_mcast_sock.h>
/* convenience wrapper */
static void fd_close(struct osmo_fd *ofd)
{
/* multicast memberships of socket are implicitly dropped when
* socket is closed */
osmo_fd_unregister(ofd);
close(ofd->fd);
ofd->fd = -1;
ofd->when = 0;
}
/* server socket is what we use for transmission. It is not subscribed
* to a multicast group or locally bound, but it is just a normal UDP
* socket that's connected to the remote mcast group + port */
int mcast_server_sock_setup(struct osmo_fd *ofd, const char* tx_mcast_group, int tx_mcast_port,
int loopback)
{
int rc;
/* setup mcast server socket */
rc = osmo_sock_init_ofd(ofd, AF_INET, SOCK_DGRAM, IPPROTO_UDP,
tx_mcast_group, tx_mcast_port, OSMO_SOCK_F_CONNECT);
if (rc < 0) {
perror("Failed to create Multicast Server Socket");
return rc;
}
/* determines whether sent mcast packets should be looped back to the local sockets.
* loopback must be enabled if the mcast client is on the same machine */
rc = setsockopt(ofd->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &loopback, sizeof(loopback));
if (rc < 0) {
perror("Failed to configure multicast loopback.\n");
fd_close(ofd);
return rc;
}
return 0;
}
/* the client socket is what we use for reception. It is a UDP socket
* that's bound to the GSMTAP UDP port and subscribed to the respective
* multicast group */
int mcast_client_sock_setup(struct osmo_fd *ofd, const char *mcast_group, int mcast_port,
int (*fd_rx_cb)(struct osmo_fd *ofd, unsigned int what),
void *osmo_fd_data)
{
struct ip_mreq mreq;
int rc, loopback = 1, all = 0;
ofd->cb = fd_rx_cb;
ofd->when = BSC_FD_READ;
ofd->data = osmo_fd_data;
/* Create mcast client socket */
rc = osmo_sock_init_ofd(ofd, AF_INET, SOCK_DGRAM, IPPROTO_UDP,
NULL, mcast_port, OSMO_SOCK_F_BIND);
if (rc < 0) {
perror("Could not create mcast client socket");
return rc;
}
/* Enable loopback of msgs to the host. */
/* Loopback must be enabled for the client, so multiple
* processes are able to receive a mcast package. */
rc = setsockopt(ofd->fd, IPPROTO_IP, IP_MULTICAST_LOOP,
&loopback, sizeof(loopback));
if (rc < 0) {
perror("Failed to enable IP_MULTICAST_LOOP");
fd_close(ofd);
return rc;
}
/* Configure and join the multicast group */
memset(&mreq, 0, sizeof(mreq));
mreq.imr_multiaddr.s_addr = inet_addr(mcast_group);
mreq.imr_interface.s_addr = htonl(INADDR_ANY);
rc = setsockopt(ofd->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
if (rc < 0) {
perror("Failed to join to mcast goup");
fd_close(ofd);
return rc;
}
/* this option will set the delivery option so that only packets
* from sockets we are subscribed to via IP_ADD_MEMBERSHIP are received */
if (setsockopt(ofd->fd, IPPROTO_IP, IP_MULTICAST_ALL, &all, sizeof(all)) < 0) {
perror("Failed to modify delivery policy to explicitly joined.\n");
fd_close(ofd);
return rc;
}
return 0;
}
struct mcast_bidir_sock *
mcast_bidir_sock_setup(void *ctx, const char *tx_mcast_group, int tx_mcast_port,
const char *rx_mcast_group, int rx_mcast_port, int loopback,
int (*fd_rx_cb)(struct osmo_fd *ofd, unsigned int what),
void *osmo_fd_data)
{
struct mcast_bidir_sock *bidir_sock = talloc(ctx, struct mcast_bidir_sock);
int rc;
if (!bidir_sock)
return NULL;
rc = mcast_client_sock_setup(&bidir_sock->rx_ofd, rx_mcast_group, rx_mcast_port,
fd_rx_cb, osmo_fd_data);
if (rc < 0) {
talloc_free(bidir_sock);
return NULL;
}
rc = mcast_server_sock_setup(&bidir_sock->tx_ofd, tx_mcast_group, tx_mcast_port, loopback);
if (rc < 0) {
fd_close(&bidir_sock->rx_ofd);
talloc_free(bidir_sock);
return NULL;
}
return bidir_sock;
}
int mcast_bidir_sock_tx(struct mcast_bidir_sock *bidir_sock, void* data,
int data_len)
{
return send(bidir_sock->tx_ofd.fd, data, data_len, 0);
}
int mcast_bidir_sock_rx(struct mcast_bidir_sock *bidir_sock, void* buf, int buf_len)
{
return recv(bidir_sock->rx_ofd.fd, buf, buf_len, 0);
}
void mcast_bidir_sock_close(struct mcast_bidir_sock *bidir_sock)
{
fd_close(&bidir_sock->tx_ofd);
fd_close(&bidir_sock->rx_ofd);
talloc_free(bidir_sock);
}
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