[v6,10/14] net: dgram: add unix socket

Commit Message

Laurent Vivier July 22, 2022, 6:56 p.m. UTC

Signed-off-by: Laurent Vivier <[e-mail]>
Reviewed-by: Stefano Brivio <[e-mail]>
---
 net/dgram.c     | 65 ++++++++++++++++++++++++++++++++++++++++++++++---
 qapi/net.json   |  2 +-
 qemu-options.hx |  1 +
 3 files changed, 64 insertions(+), 4 deletions(-)

Patch

diff --git a/net/dgram.c b/net/dgram.c
index 16e2d909755c..9f3eafee3b67 100644
--- a/net/dgram.c
+++ b/net/dgram.c
@@ -86,8 +86,15 @@  static ssize_t net_dgram_receive_dgram(NetClientState *nc,
 
     do {
         if (s->dgram_dst) {
-            ret = sendto(s->fd, buf, size, 0, s->dgram_dst,
-                         sizeof(struct sockaddr_in));
+            socklen_t len;
+
+            if (s->dgram_dst->sa_family == AF_INET) {
+                len = sizeof(struct sockaddr_in);
+            } else {
+                len = sizeof(struct sockaddr_un);
+            }
+
+            ret = sendto(s->fd, buf, size, 0, s->dgram_dst, len);
         } else {
             ret = send(s->fd, buf, size, 0);
         }
@@ -509,7 +516,7 @@  static int net_dgram_udp_init(NetClientState *peer,
         }
     } else {
         if (local->type != SOCKET_ADDRESS_TYPE_FD) {
-            error_setg(errp, "type=inet requires remote parameter");
+            error_setg(errp, "type=inet or unix require remote parameter");
             return -1;
         }
     }
@@ -559,6 +566,58 @@  static int net_dgram_udp_init(NetClientState *peer,
 
         break;
     }
+    case SOCKET_ADDRESS_TYPE_UNIX: {
+        struct sockaddr_un laddr_un, raddr_un;
+
+        ret = unlink(local->u.q_unix.path);
+        if (ret < 0 && errno != ENOENT) {
+            error_setg_errno(errp, errno, "failed to unlink socket %s",
+                             local->u.q_unix.path);
+            return -1;
+        }
+
+        laddr_un.sun_family = PF_UNIX;
+        ret = snprintf(laddr_un.sun_path, sizeof(laddr_un.sun_path), "%s",
+                       local->u.q_unix.path);
+        if (ret < 0 || ret >= sizeof(laddr_un.sun_path)) {
+            error_setg(errp, "UNIX socket path '%s' is too long",
+                       local->u.q_unix.path);
+            error_append_hint(errp, "Path must be less than %zu bytes\n",
+                              sizeof(laddr_un.sun_path));
+        }
+
+        raddr_un.sun_family = PF_UNIX;
+        ret = snprintf(raddr_un.sun_path, sizeof(raddr_un.sun_path), "%s",
+                       remote->u.q_unix.path);
+        if (ret < 0 || ret >= sizeof(raddr_un.sun_path)) {
+            error_setg(errp, "UNIX socket path '%s' is too long",
+                       remote->u.q_unix.path);
+            error_append_hint(errp, "Path must be less than %zu bytes\n",
+                              sizeof(raddr_un.sun_path));
+        }
+
+        fd = qemu_socket(PF_UNIX, SOCK_DGRAM, 0);
+        if (fd < 0) {
+            error_setg_errno(errp, errno, "can't create datagram socket");
+            return -1;
+        }
+
+        ret = bind(fd, (struct sockaddr *)&laddr_un, sizeof(laddr_un));
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "can't bind unix=%s to socket",
+                             laddr_un.sun_path);
+            closesocket(fd);
+            return -1;
+        }
+        qemu_socket_set_nonblock(fd);
+
+        dgram_dst = g_malloc(sizeof(raddr_un));
+        memcpy(dgram_dst, &raddr_un, sizeof(raddr_un));
+
+        info_str = g_strdup_printf("udp=%s:%s",
+                                   laddr_un.sun_path, raddr_un.sun_path);
+        break;
+    }
     case SOCKET_ADDRESS_TYPE_FD: {
         SocketAddress *sa;
         SocketAddressType sa_type;
diff --git a/qapi/net.json b/qapi/net.json
index 518f288758b0..894c06a82b1b 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -600,7 +600,7 @@ 
 # @remote: remote address
 # @local: local address
 #
-# Only SocketAddress types 'inet' and 'fd' are supported.
+# Only SocketAddress types 'unix', 'inet' and 'fd' are supported.
 #
 # The code checks there is at least one of these options and reports an error
 # if not. If remote address is present and it's a multicast address, local
diff --git a/qemu-options.hx b/qemu-options.hx
index 827a951a9ef2..33c5bd72af21 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2736,6 +2736,7 @@  DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
     "                configure a network backend to connect to a multicast maddr and port\n"
     "                use ``local.host=addr`` to specify the host address to send packets from\n"
     "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n"
+    "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n"
     "-netdev dgram,id=str,local.type=fd,local.str=h\n"
     "                configure a network backend to connect to another network\n"
     "                using an UDP tunnel\n"