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authorMarc-André Lureau <marcandre.lureau@redhat.com>2019-03-11 18:25:05 +0100
committerJason Wang <jasowang@redhat.com>2019-03-29 15:22:18 +0800
commitfdec16e3c2a614e2861f3086b05d444b5d8c3406 (patch)
treed7e824672e5589835bf706e1f9147de4da7aadd9 /net/socket.c
parenta04d91c701251a9b32b7364ddb48029ba024cb75 (diff)
net/socket: learn to talk with a unix dgram socket
-net socket has a fd argument, and may be passed pre-opened sockets. TCP sockets use framing. UDP sockets have datagram boundaries. When given a unix dgram socket, it will be able to read from it, but will attempt to send on the dgram_dst, which is unset. The other end will not receive the data. Let's teach -net socket to recognize a UNIX DGRAM socket, and use the regular send() command (without dgram_dst). This makes running slirp out-of-process possible that way (python pseudo-code): a, b = socket.socketpair(socket.AF_UNIX, socket.SOCK_DGRAM) subprocess.Popen('qemu -net socket,fd=%d -net user' % a.fileno(), shell=True) subprocess.Popen('qemu ... -net nic -net socket,fd=%d' % b.fileno(), shell=True) Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'net/socket.c')
-rw-r--r--net/socket.c25
1 files changed, 21 insertions, 4 deletions
diff --git a/net/socket.c b/net/socket.c
index 90ef3517be..c92354049b 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -119,9 +119,13 @@ static ssize_t net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf,
ssize_t ret;
do {
- ret = qemu_sendto(s->fd, buf, size, 0,
- (struct sockaddr *)&s->dgram_dst,
- sizeof(s->dgram_dst));
+ if (s->dgram_dst.sin_family != AF_UNIX) {
+ ret = qemu_sendto(s->fd, buf, size, 0,
+ (struct sockaddr *)&s->dgram_dst,
+ sizeof(s->dgram_dst));
+ } else {
+ ret = send(s->fd, buf, size, 0);
+ }
} while (ret == -1 && errno == EINTR);
if (ret == -1 && errno == EAGAIN) {
@@ -336,6 +340,15 @@ static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
int newfd;
NetClientState *nc;
NetSocketState *s;
+ SocketAddress *sa;
+ SocketAddressType sa_type;
+
+ sa = socket_local_address(fd, errp);
+ if (!sa) {
+ return NULL;
+ }
+ sa_type = sa->type;
+ qapi_free_SocketAddress(sa);
/* fd passed: multicast: "learn" dgram_dst address from bound address and save it
* Because this may be "shared" socket from a "master" process, datagrams would be recv()
@@ -379,8 +392,12 @@ static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
"socket: fd=%d (cloned mcast=%s:%d)",
fd, inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
} else {
+ if (sa_type == SOCKET_ADDRESS_TYPE_UNIX) {
+ s->dgram_dst.sin_family = AF_UNIX;
+ }
+
snprintf(nc->info_str, sizeof(nc->info_str),
- "socket: fd=%d", fd);
+ "socket: fd=%d %s", fd, SocketAddressType_str(sa_type));
}
return s;