From 3a75e74c76cef8daa7944159b016c4ee7c56e568 Mon Sep 17 00:00:00 2001 From: Mike Ryan Date: Wed, 1 Dec 2010 11:16:47 -0800 Subject: net/sock: option to specify local address Add an option to specify the host IP to send multicast packets from, when using a multicast socket for networking. The option takes an IP address and sets the IP_MULTICAST_IF socket option, which causes the packets to use that IP's interface as an egress. This is useful if the host machine has several interfaces with several virtual networks across disparate interfaces. Signed-off-by: Mike Ryan Signed-off-by: Michael S. Tsirkin --- net/socket.c | 52 +++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 39 insertions(+), 13 deletions(-) (limited to 'net/socket.c') diff --git a/net/socket.c b/net/socket.c index 1c4e153e3f..916c2a8e10 100644 --- a/net/socket.c +++ b/net/socket.c @@ -149,7 +149,7 @@ static void net_socket_send_dgram(void *opaque) qemu_send_packet(&s->nc, s->buf, size); } -static int net_socket_mcast_create(struct sockaddr_in *mcastaddr) +static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr *localaddr) { struct ip_mreq imr; int fd; @@ -183,7 +183,11 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr) /* Add host to multicast group */ imr.imr_multiaddr = mcastaddr->sin_addr; - imr.imr_interface.s_addr = htonl(INADDR_ANY); + if (localaddr) { + imr.imr_interface = *localaddr; + } else { + imr.imr_interface.s_addr = htonl(INADDR_ANY); + } ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (const char *)&imr, sizeof(struct ip_mreq)); @@ -201,6 +205,15 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr) goto fail; } + /* If a bind address is given, only send packets from that address */ + if (localaddr != NULL) { + ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, localaddr, sizeof(*localaddr)); + if (ret < 0) { + perror("setsockopt(IP_MULTICAST_IF)"); + goto fail; + } + } + socket_set_nonblock(fd); return fd; fail: @@ -248,7 +261,7 @@ static NetSocketState *net_socket_fd_init_dgram(VLANState *vlan, return NULL; } /* clone dgram socket */ - newfd = net_socket_mcast_create(&saddr); + newfd = net_socket_mcast_create(&saddr, NULL); if (newfd < 0) { /* error already reported by net_socket_mcast_create() */ close(fd); @@ -468,17 +481,26 @@ static int net_socket_connect_init(VLANState *vlan, static int net_socket_mcast_init(VLANState *vlan, const char *model, const char *name, - const char *host_str) + const char *host_str, + const char *localaddr_str) { NetSocketState *s; int fd; struct sockaddr_in saddr; + struct in_addr localaddr, *param_localaddr; if (parse_host_port(&saddr, host_str) < 0) return -1; + if (localaddr_str != NULL) { + if (inet_aton(localaddr_str, &localaddr) == 0) + return -1; + param_localaddr = &localaddr; + } else { + param_localaddr = NULL; + } - fd = net_socket_mcast_create(&saddr); + fd = net_socket_mcast_create(&saddr, param_localaddr); if (fd < 0) return -1; @@ -505,8 +527,9 @@ int net_init_socket(QemuOpts *opts, if (qemu_opt_get(opts, "listen") || qemu_opt_get(opts, "connect") || - qemu_opt_get(opts, "mcast")) { - error_report("listen=, connect= and mcast= is invalid with fd="); + qemu_opt_get(opts, "mcast") || + qemu_opt_get(opts, "localaddr")) { + error_report("listen=, connect=, mcast= and localaddr= is invalid with fd=\n"); return -1; } @@ -524,8 +547,9 @@ int net_init_socket(QemuOpts *opts, if (qemu_opt_get(opts, "fd") || qemu_opt_get(opts, "connect") || - qemu_opt_get(opts, "mcast")) { - error_report("fd=, connect= and mcast= is invalid with listen="); + qemu_opt_get(opts, "mcast") || + qemu_opt_get(opts, "localaddr")) { + error_report("fd=, connect=, mcast= and localaddr= is invalid with listen=\n"); return -1; } @@ -539,8 +563,9 @@ int net_init_socket(QemuOpts *opts, if (qemu_opt_get(opts, "fd") || qemu_opt_get(opts, "listen") || - qemu_opt_get(opts, "mcast")) { - error_report("fd=, listen= and mcast= is invalid with connect="); + qemu_opt_get(opts, "mcast") || + qemu_opt_get(opts, "localaddr")) { + error_report("fd=, listen=, mcast= and localaddr= is invalid with connect=\n"); return -1; } @@ -550,7 +575,7 @@ int net_init_socket(QemuOpts *opts, return -1; } } else if (qemu_opt_get(opts, "mcast")) { - const char *mcast; + const char *mcast, *localaddr; if (qemu_opt_get(opts, "fd") || qemu_opt_get(opts, "connect") || @@ -560,8 +585,9 @@ int net_init_socket(QemuOpts *opts, } mcast = qemu_opt_get(opts, "mcast"); + localaddr = qemu_opt_get(opts, "localaddr"); - if (net_socket_mcast_init(vlan, "socket", name, mcast) == -1) { + if (net_socket_mcast_init(vlan, "socket", name, mcast, localaddr) == -1) { return -1; } } else { -- cgit v1.2.3