From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56948) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gLCtz-00018g-17 for qemu-devel@nongnu.org; Fri, 09 Nov 2018 14:57:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gLCtt-0000o0-UZ for qemu-devel@nongnu.org; Fri, 09 Nov 2018 14:57:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33052) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gLCtt-0000nK-Gg for qemu-devel@nongnu.org; Fri, 09 Nov 2018 14:57:05 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 89C6E81E05 for ; Fri, 9 Nov 2018 19:57:04 +0000 (UTC) From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Fri, 9 Nov 2018 23:56:53 +0400 Message-Id: <20181109195653.11867-1-marcandre.lureau@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH] RFC: net/socket: learn to talk with a unix dgram socket List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: jasowang@redhat.com, rjones@redhat.com, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= -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 =3D socket.socketpair(socket.AF_UNIX, socket.SOCK_DGRAM) subprocess.Popen('qemu -net socket,fd=3D%d -net user' % a.fileno(), shell= =3DTrue) subprocess.Popen('qemu ... -net nic -net socket,fd=3D%d' % b.fileno(), sh= ell=3DTrue) (to make slirp a seperate project altogether, we would have to have some compatibility code and/or deprecate various options & HMP commands for dynamic port forwarding etc - but this looks like a reachable goal) Signed-off-by: Marc-Andr=C3=A9 Lureau --- net/socket.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/net/socket.c b/net/socket.c index 7095eb749f..8a9c30892d 100644 --- a/net/socket.c +++ b/net/socket.c @@ -119,9 +119,13 @@ static ssize_t net_socket_receive_dgram(NetClientSta= te *nc, const uint8_t *buf, ssize_t ret; =20 do { - ret =3D qemu_sendto(s->fd, buf, size, 0, - (struct sockaddr *)&s->dgram_dst, - sizeof(s->dgram_dst)); + if (s->dgram_dst.sin_family !=3D AF_UNIX) { + ret =3D qemu_sendto(s->fd, buf, size, 0, + (struct sockaddr *)&s->dgram_dst, + sizeof(s->dgram_dst)); + } else { + ret =3D send(s->fd, buf, size, 0); + } } while (ret =3D=3D -1 && errno =3D=3D EINTR); =20 if (ret =3D=3D -1 && errno =3D=3D EAGAIN) { @@ -322,6 +326,15 @@ static NetSocketState *net_socket_fd_init_dgram(NetC= lientState *peer, int newfd; NetClientState *nc; NetSocketState *s; + SocketAddress *sa; + SocketAddressType sa_type; + + sa =3D socket_local_address(fd, errp); + if (!sa) { + return NULL; + } + sa_type =3D sa->type; + qapi_free_SocketAddress(sa); =20 /* fd passed: multicast: "learn" dgram_dst address from bound addres= s and save it * Because this may be "shared" socket from a "master" process, data= grams would be recv() @@ -365,8 +378,12 @@ static NetSocketState *net_socket_fd_init_dgram(NetC= lientState *peer, "socket: fd=3D%d (cloned mcast=3D%s:%d)", fd, inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port)); } else { + if (sa_type =3D=3D SOCKET_ADDRESS_TYPE_UNIX) { + s->dgram_dst.sin_family =3D AF_UNIX; + } + snprintf(nc->info_str, sizeof(nc->info_str), - "socket: fd=3D%d", fd); + "socket: fd=3D%d %s", fd, SocketAddressType_str(sa_type= )); } =20 return s; --=20 2.19.1.708.g4ede3d42df