diff options
| author | Harald Welte <laforge@osmocom.org> | 2020-03-07 14:59:05 +0100 |
|---|---|---|
| committer | Harald Welte <laforge@osmocom.org> | 2020-03-10 19:08:51 +0100 |
| commit | 44b9926c84c9cb9a3fcf2d0770d4951a4eab5fe2 (patch) | |
| tree | 5ceb5a159345d46e67380e2bdab081c137cf0239 | |
| parent | 31c29ea0517904cd588654426fb133aeb34af506 (diff) | |
socket: Add osmo_sock_mcast_iface_set() to bind multicast to device
Change-Id: Ib52d22710020b56965aefcef09bde8247ace4a9c
Related: OS#2966
| -rw-r--r-- | include/osmocom/core/socket.h | 1 | ||||
| -rw-r--r-- | src/socket.c | 22 |
2 files changed, 23 insertions, 0 deletions
diff --git a/include/osmocom/core/socket.h b/include/osmocom/core/socket.h index e26ca0d3..129612c6 100644 --- a/include/osmocom/core/socket.h +++ b/include/osmocom/core/socket.h @@ -87,6 +87,7 @@ int osmo_sock_get_remote_ip_port(int fd, char *port, size_t len); int osmo_sock_mcast_loop_set(int fd, bool enable); int osmo_sock_mcast_ttl_set(int fd, uint8_t ttl); int osmo_sock_mcast_all_set(int fd, bool enable); +int osmo_sock_mcast_iface_set(int fd, const char *ifname); int osmo_sock_mcast_subscribe(int fd, const char *grp_addr); int osmo_sock_local_ip(char *local_ip, const char *remote_ip); diff --git a/src/socket.c b/src/socket.c index 9b1d30ec..503ceaf4 100644 --- a/src/socket.c +++ b/src/socket.c @@ -41,6 +41,7 @@ #include <sys/socket.h> #include <sys/types.h> #include <sys/un.h> +#include <net/if.h> #include <netinet/in.h> #include <arpa/inet.h> @@ -1194,6 +1195,27 @@ int osmo_sock_mcast_ttl_set(int fd, uint8_t ttl) } } +/*! Set the network device to which we should bind the multicast socket + * \param[in] fd file descriptor of related socket + * \param[in] ifname name of network interface to user for multicast + * \returns 0 on success; negative otherwise */ +int osmo_sock_mcast_iface_set(int fd, const char *ifname) +{ + unsigned int ifindex; + struct ip_mreqn mr; + + /* first, resolve interface name to ifindex */ + ifindex = if_nametoindex(ifname); + if (ifindex == 0) + return -errno; + + /* next, configure kernel to use that ifindex for this sockets multicast traffic */ + memset(&mr, 0, sizeof(mr)); + mr.imr_ifindex = ifindex; + return setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, &mr, sizeof(mr)); +} + + /*! Enable/disable receiving all multicast packets, even for non-subscribed groups * \param[in] fd file descriptor of related socket * \param[in] enable Enable or Disable receiving of all packets |