* [Qemu-devel] [PATCH] QEMU multicast socket support v4 (UML mcast compatible)
@ 2005-12-13 22:57 JuanJo Ciarlante
0 siblings, 0 replies; only message in thread
From: JuanJo Ciarlante @ 2005-12-13 22:57 UTC (permalink / raw)
To: qemu-devel
[-- Attachment #1.1: Type: text/plain, Size: 2064 bytes --]
Hi!
Attached patch (against qemu CVS 2005-12-10) adds multicast support for
QEMU socket transport, ie: run several stateless possibly non-local QEMUs
on same virtual ethernet "BUS".
User-mode-linux (UML) compatible (tested).
An excerpt from qemu-doc.texi:
`-net socket[,vlan=n][,fd=h][,mcast=maddr:port]'
Create a VLAN n shared with another QEMU virtual machines using
a UDP multicast socket, effectively making a bus for every QEMU
with same multicast address maddr and port. NOTES:
1. Several QEMU can be running on different hosts and share same
bus (assuming correct multicast setup for these hosts).
2. mcast support is compatible with User Mode Linux (argument
`ethN=mcast'), see http://user-mode-linux.sf.net.
Example:
# launch one QEMU instance
qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net socket,mcast=230.0.0.1:1234
# launch another QEMU instance on same "bus"
qemu linux.img -net nic,macaddr=52:54:00:12:34:57 -net socket,mcast=230.0.0.1:1234
# launch yet another QEMU instance on same "bus"
qemu linux.img -net nic,macaddr=52:54:00:12:34:58 -net socket,mcast=230.0.0.1:1234
Example (User Mode Linux compat.):
# launch QEMU instance (note mcast address selected is UML's default)
qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net socket,mcast=239.192.168.1:1102
# launch UML
/path/to/linux ubd0=/path/to/root_fs eth0=mcast
Available under GPLv2 from
http://www.irrigacion.gov.ar/juanjo/qemu/
Changes
-------
v4 (2005-12-12):
* Tested mcast user-mode-linux compatibility
* Minor tweaks
v3 (2005-12-07):
* correctly close fds if any socket syscall fails (ie. close'em don't leak'em ;)
v2 (2005-12-07):
* 1st public release
EnjoY
--
--Juanjo
# Juan Jose Ciarlante (JuanJo) jjo ;at; mendoza.gov.ar #
# GnuPG Public Key: gpg --keyserver wwwkeys.eu.pgp.net --recv-key 66727177 #
# Key fingerprint: 0D2F 3E5D 8B5C 729E 0560 F453 A3F7 E249 6672 7177 #
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diff --git a/README.qemu-mcast b/README.qemu-mcast
new file mode 100644
index 0000000..4021be5
--- /dev/null
+++ b/README.qemu-mcast
@@ -0,0 +1,56 @@
+QEMU multicast support
+======================
+Author: JuanJo Ciarlante jjo()um.edu.ar, juanjosec()gmail.com
+Date: Mon Dec 12 12:38:11 ART 2005
+Keywords: qemu, socket, multicast, UDP, mcast, UML
+
+Attached patch (against qemu CVS 2005-12-10) adds multicast support for
+QEMU socket transport, ie: run several stateless possibly non-local QEMUs
+on same virtual ethernet "BUS".
+User-mode-linux (UML) compatible (tested).
+
+An excerpt from qemu-doc.texi:
+
+ `-net socket[,vlan=n][,fd=h][,mcast=maddr:port]'
+ Create a VLAN n shared with another QEMU virtual machines using
+ a UDP multicast socket, effectively making a bus for every QEMU
+ with same multicast address maddr and port. NOTES:
+ 1. Several QEMU can be running on different hosts and share same
+ bus (assuming correct multicast setup for these hosts).
+ 2. mcast support is compatible with User Mode Linux (argument
+ `ethN=mcast'), see http://user-mode-linux.sf.net.
+ Example:
+ # launch one QEMU instance
+ qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net socket,mcast=230.0.0.1:1234
+ # launch another QEMU instance on same "bus"
+ qemu linux.img -net nic,macaddr=52:54:00:12:34:57 -net socket,mcast=230.0.0.1:1234
+ # launch yet another QEMU instance on same "bus"
+ qemu linux.img -net nic,macaddr=52:54:00:12:34:58 -net socket,mcast=230.0.0.1:1234
+ Example (User Mode Linux compat.):
+ # launch QEMU instance (note mcast address selected is UML's default)
+ qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net socket,mcast=239.192.168.1:1102
+ # launch UML
+ /path/to/linux ubd0=/path/to/root_fs eth0=mcast
+
+Available under GPLv2 from
+ http://www.irrigacion.gov.ar/juanjo/qemu/
+
+
+Changes
+-------
+v4 (2005-12-12):
+ * Tested mcast user-mode-linux compatibility
+ * Minor tweaks
+
+v3 (2005-12-07):
+ * correctly close fds if any socket syscall fails (ie. close'em don't leak'em ;)
+
+v2 (2005-12-07):
+ * 1st public release
+
+
+--Juanjo
+
+# Juan Jose Ciarlante (JuanJo) jjo ;at; mendoza.gov.ar #
+# GnuPG Public Key: gpg --keyserver wwwkeys.eu.pgp.net --recv-key 66727177 #
+# Key fingerprint: 0D2F 3E5D 8B5C 729E 0560 F453 A3F7 E249 6672 7177 #
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 7ec41f5..d630adf 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -293,6 +293,41 @@ qemu linux.img -net nic,macaddr=52:54:00
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[,vlan=n][,fd=h][,mcast=maddr:port]
+
+Create a VLAN @var{n} shared with another QEMU virtual
+machines using a UDP multicast socket, effectively making a bus for
+every QEMU with same multicast address @var{maddr} and @var{port}.
+NOTES:
+@enumerate
+@item
+Several QEMU can be running on different hosts and share same bus (assuming
+correct multicast setup for these hosts).
+@item
+mcast support is compatible with User Mode Linux (argument @option{eth@var{N}=mcast}), see
+@url{user-mode-linux.sf.net}.
+@end enumerate
+
+
+Example:
+@example
+# launch one QEMU instance
+qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net socket,mcast=230.0.0.1:1234
+# launch another QEMU instance on same "bus"
+qemu linux.img -net nic,macaddr=52:54:00:12:34:57 -net socket,mcast=230.0.0.1:1234
+# launch yet another QEMU instance on same "bus"
+qemu linux.img -net nic,macaddr=52:54:00:12:34:58 -net socket,mcast=230.0.0.1:1234
+@end example
+
+Example (User Mode Linux compat.):
+@example
+# launch QEMU instance (note mcast address selected is UML's default)
+qemu linux.img -net nic,macaddr=52:54:00:12:34:56 -net socket,mcast=239.192.168.1:1102
+# launch UML
+/path/to/linux ubd0=/path/to/root_fs eth0=mcast
+@end example
+
+
@item -net none
Indicate that no network devices should be configured. It is used to
override the default configuration which is activated if no
diff --git a/vl.c b/vl.c
index 4b1e72e..4492418 100644
--- a/vl.c
+++ b/vl.c
@@ -2131,8 +2131,17 @@ typedef struct NetSocketState {
int index;
int packet_len;
uint8_t buf[4096];
+ struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
} NetSocketState;
+static int qemu_socket_is_dgram(const struct NetSocketState *s)
+{
+ /* This could also be: getsockopt(s->fd, SOL_SOCKET, SO_TYPE, &opt, &optlen)
+ * but I would cost an extra syscall per write (DGRAM writes don't require sending pkt length)
+ */
+ return (s->dgram_dst.sin_addr.s_addr!=0);
+}
+
typedef struct NetSocketListenState {
VLANState *vlan;
int fd;
@@ -2145,8 +2154,12 @@ static void net_socket_receive(void *opa
uint32_t len;
len = htonl(size);
- unix_write(s->fd, (const uint8_t *)&len, sizeof(len));
- unix_write(s->fd, buf, size);
+ if (qemu_socket_is_dgram(s)) {
+ sendto(s->fd, buf, size, 0, (struct sockaddr *)&s->dgram_dst, sizeof(s->dgram_dst));
+ } else {
+ unix_write(s->fd, (const uint8_t *)&len, sizeof(len));
+ unix_write(s->fd, buf, size);
+ }
}
static void net_socket_send(void *opaque)
@@ -2164,6 +2177,11 @@ static void net_socket_send(void *opaque
qemu_set_fd_handler(s->fd, NULL, NULL, NULL);
return;
}
+ if (qemu_socket_is_dgram(s)) {
+ s->index = 0;
+ s->state = 1;
+ s->packet_len = size;
+ }
buf = buf1;
while (size > 0) {
/* reassemble a packet from the network */
@@ -2336,6 +2354,75 @@ static int net_socket_connect_init(VLANS
return 0;
}
+static int net_socket_mcast_init(VLANState *vlan, const char *host_str)
+{
+ NetSocketState *s;
+ int fd=-1, ret, val;
+ struct sockaddr_in saddr;
+ struct ip_mreq imr;
+
+ if (parse_host_port(&saddr, host_str) < 0)
+ return -1;
+
+ if (!IN_MULTICAST(ntohl(saddr.sin_addr.s_addr))) {
+ fprintf(stderr, "qemu: error: specified mcastaddr \"%s\" (0x%08x) does not contain a multicast address\n",
+ inet_ntoa(saddr.sin_addr), ntohl(saddr.sin_addr.s_addr));
+ return -1;
+
+ }
+ fd = socket(PF_INET, SOCK_DGRAM, 0);
+ if (fd < 0) {
+ perror("socket(PF_INET, SOCK_DGRAM)");
+ return -1;
+ }
+
+ /* Add host to multicast group */
+ imr.imr_multiaddr = saddr.sin_addr;
+ imr.imr_interface.s_addr = htonl(INADDR_ANY);
+
+ ret = setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (void *) &imr, sizeof(struct ip_mreq));
+ if (ret < 0) {
+ perror("setsockopt(IP_ADD_MEMBERSHIP)");
+ goto fail;
+ }
+
+ /* Force mcast msgs to loopback (eg. several QEMUs in same host */
+ val = 1;
+ ret=setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP, &val, sizeof(val));
+ if (ret < 0) {
+ perror("setsockopt(SOL_IP, IP_MULTICAST_LOOP)");
+ goto fail;
+ }
+ ret=setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+ if (ret < 0) {
+ perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
+ goto fail;
+ }
+
+ ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
+ if (ret < 0) {
+ perror("bind");
+ goto fail;
+ }
+
+ fcntl(fd, F_SETFL, O_NONBLOCK);
+
+ s = net_socket_fd_init(vlan, fd, 1);
+ if (!s)
+ goto fail;
+
+ /* Connectionless: save mcast address for sendto() */
+ s->dgram_dst = saddr;
+
+ snprintf(s->vc->info_str, sizeof(s->vc->info_str),
+ "socket: mcast at %s:%d",
+ inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+ return 0;
+fail:
+ if (fd>=0) close(fd);
+ return -1;
+}
+
#endif /* !_WIN32 */
static int get_param_value(char *buf, int buf_size,
@@ -2472,6 +2559,8 @@ int net_client_init(const char *str)
ret = net_socket_listen_init(vlan, buf);
} else if (get_param_value(buf, sizeof(buf), "connect", p) > 0) {
ret = net_socket_connect_init(vlan, buf);
+ } else if (get_param_value(buf, sizeof(buf), "mcast", p) > 0) {
+ ret = net_socket_mcast_init(vlan, buf);
} else {
fprintf(stderr, "Unknown socket options: %s\n", p);
return -1;
@@ -3810,6 +3899,8 @@ void help(void)
" use 'fd=h' to connect to an already opened TAP interface\n"
"-net socket[,vlan=n][,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][,fd=h][,mcast=maddr:port]\n"
+ " create a vlan 'n' with another QEMUs on multicast maddr and port\n"
#endif
"-net none use it alone to have zero network devices; if no -net option\n"
" is provided, the default is '-net nic -net user'\n"
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2005-12-13 22:57 [Qemu-devel] [PATCH] QEMU multicast socket support v4 (UML mcast compatible) JuanJo Ciarlante
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