On Wed, Nov 10, 2010 at 05:47:35PM -0800, Mike Ryan wrote:
> Add an option to specify the host interface to send multicast packets on
> when using a multicast socket for networking. The option takes the name
> of a host interface (e.g., eth0) and sets the IP_MULTICAST_IF socket
> option, which causes the packets to use that interface as an egress.
>
> This is useful if the host machine has several interfaces with several
> virtual networks across disparate interfaces.
> @@ -201,6 +203,23 @@ static int net_socket_mcast_create(struct sockaddr_in
> *mcastaddr)
> goto fail;
> }
>
> + /* If an interface name is given, only send packets out that interface */
> + if (interface != NULL) {
> + strncpy(ifr.ifr_name, interface, IFNAMSIZ);
> + ret = ioctl(fd, SIOCGIFADDR, &ifr);
> + if (ret < 0) {
> + fprintf(stderr, "qemu: error: specified interface \"%s\" does
> not exist\n", interface);
> + goto fail;
> + }
> +
> + maddr = ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr;
> + ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, &maddr,
> sizeof(maddr));
> + if (ret < 0) {
> + perror("setsockopt(IP_MULTICAST_IF)");
> + goto fail;
> + }
Let's let the user pass in the IP address? That would solve the
portability issue. Further, we could be doing IPv6, right?
So you'd need IPV6_MULTICAST_IF?
Also - you might also want to control
IP_MULTICAST_LOOP/IPV6_MULTICAST_LOOP?
> + }
> +
> socket_set_nonblock(fd);
> return fd;
> fail:
> @@ -248,7 +267,7 @@ 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);
> @@ -468,7 +487,8 @@ 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 *interface)
> {
> NetSocketState *s;
> int fd;
> @@ -478,7 +498,7 @@ static int net_socket_mcast_init(VLANState *vlan,
> return -1;
>
>
> - fd = net_socket_mcast_create(&saddr);
> + fd = net_socket_mcast_create(&saddr, interface);
> if (fd < 0)
> return -1;
>
> @@ -505,8 +525,9 @@ 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, "interface")) {
> + error_report("listen=, connect=, mcast= and interface= is
> invalid with fd=\n");
> return -1;
> }
>
> @@ -524,8 +545,9 @@ 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, "interface")) {
> + error_report("fd=, connect=, mcast= and interface= is invalid
> with listen=\n");
> return -1;
> }
>
> @@ -539,8 +561,9 @@ 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, "interface")) {
> + error_report("fd=, listen=, mcast= and interface= is invalid
> with connect=\n");
> return -1;
> }
>
> @@ -550,7 +573,7 @@ int net_init_socket(QemuOpts *opts,
> return -1;
> }
> } else if (qemu_opt_get(opts, "mcast")) {
> - const char *mcast;
> + const char *mcast, *interface;
>
> if (qemu_opt_get(opts, "fd") ||
> qemu_opt_get(opts, "connect") ||
> @@ -560,8 +583,9 @@ int net_init_socket(QemuOpts *opts,
> }
>
> mcast = qemu_opt_get(opts, "mcast");
> + interface = qemu_opt_get(opts, "interface");
>
> - if (net_socket_mcast_init(vlan, "socket", name, mcast) == -1) {
> + if (net_socket_mcast_init(vlan, "socket", name, mcast, interface) ==
> -1) {
> return -1;
> }
> } else {
> diff --git a/qemu-common.h b/qemu-common.h
> index b3957f1..e8bc4af 100644
> --- a/qemu-common.h
> +++ b/qemu-common.h
> @@ -34,6 +34,7 @@ typedef struct DeviceState DeviceState;
> #include <fcntl.h>
> #include <sys/stat.h>
> #include <assert.h>
> +#include <sys/ioctl.h>
>
> #ifndef O_LARGEFILE
> #define O_LARGEFILE 0
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 4d99a58..e2c4cfa 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1061,8 +1061,9 @@ DEF("net", HAS_ARG, QEMU_OPTION_net,
> #endif
> "-net
> socket[,vlan=n][,name=str][,fd=h][,listen=[host]:port][,connect=host:port]\n"
> " connect the vlan 'n' to another VLAN using a socket
> connection\n"
> - "-net socket[,vlan=n][,name=str][,fd=h][,mcast=maddr:port]\n"
> + "-net
> socket[,vlan=n][,name=str][,fd=h][,mcast=maddr:port[,interface=ifname]]\n"
> " connect the vlan 'n' to multicast maddr and port\n"
> + " use 'interface=ifname' to specify the host interface to
> send packets on\n"
> #ifdef CONFIG_VDE
> "-net
> vde[,vlan=n][,name=str][,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n"
> " connect the vlan 'n' to port 'n' of a vde switch
> running\n"
> @@ -1256,7 +1257,7 @@ qemu linux.img -net nic,macaddr=52:54:00:12:34:57 \
> -net socket,connect=127.0.0.1:1234
> @end example
>
> -...@item -net socket[,vl...@var{n}][,na...@var{name}][,f...@var{h}]
> [,mca...@var{maddr}:@var{port}]
> +...@item -net
> socket[,vl...@var{n}][,na...@var{name}][,f...@var{h}][,mca...@var{maddr}:@var{port}[,interfa...@var{ifname}]]
>
> Create a VLAN @var{n} shared with another QEMU virtual
> machines using a UDP multicast socket, effectively making a bus for
> @@ -1296,6 +1297,12 @@ qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \
> /path/to/linux ubd0=/path/to/root_fs eth0=mcast
> @end example
>
> +Example (send packets on host's eth0):
> +...@example
> +qemu linux.img -net nic,macaddr=52:54:00:12:34:56 \
> + -net socket,mcast=239.192.168.1:1102,interface=eth0
> +...@end example
> +
> @item -net vde[,vl...@var{n}][,na...@var{name}][,so...@var{socketpath}]
> [,po...@var{n}][,gro...@var{groupname}][,mo...@var{octalmode}]
> Connect VLAN @var{n} to PORT @var{n} of a vde switch running on host and
> listening for incoming connections on @var{socketpath}. Use GROUP
> @var{groupname}
> diff --git a/qemu_socket.h b/qemu_socket.h
> index 897a8ae..5116e4a 100644
> --- a/qemu_socket.h
> +++ b/qemu_socket.h
> @@ -24,6 +24,7 @@ int inet_aton(const char *cp, struct in_addr *ia);
> #include <arpa/inet.h>
> #include <netdb.h>
> #include <sys/un.h>
> +#include <net/if.h>
>
> #define socket_error() errno
> #define closesocket(s) close(s)
> --
> 1.7.0.4
>
