net: dgram: move mcast specific code from net_socket_fd_init_dgram()

It is less complex to manage special cases directly in
net_dgram_mcast_init() and net_dgram_udp_init().

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

net/dgram.c

@@ -259,52 +259,11 @@ static NetClientInfo net_dgram_socket_info = {
 static NetDgramState *net_dgram_fd_init(NetClientState *peer,
                                         const char *model,
                                         const char *name,
-                                        int fd, int is_fd,
+                                        int fd,
-                                        SocketAddress *mcast,
                                         Error **errp)
 {
-    struct sockaddr_in *saddr = NULL;
-    int newfd;
     NetClientState *nc;
     NetDgramState *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" dest_addr address from bound address and
-     * save it. Because this may be "shared" socket from a "master" process,
-     * datagrams would be recv() by ONLY ONE process: we must "clone" this
-     * dgram socket --jjo
-     */
-
-    if (is_fd && mcast != NULL) {
-            saddr = g_new(struct sockaddr_in, 1);
-
-            if (convert_host_port(saddr, mcast->u.inet.host, mcast->u.inet.port,
-                                  errp) < 0) {
-                goto err;
-            }
-            /* must be bound */
-            if (saddr->sin_addr.s_addr == 0) {
-                error_setg(errp, "can't setup multicast destination address");
-                goto err;
-            }
-            /* clone dgram socket */
-            newfd = net_dgram_mcast_create(saddr, NULL, errp);
-            if (newfd < 0) {
-                goto err;
-            }
-            /* clone newfd to fd, close newfd */
-            dup2(newfd, fd);
-            close(newfd);
-    }
 
     nc = qemu_new_net_client(&net_dgram_socket_info, peer, model, name);
 
@@ -314,23 +273,7 @@ static NetDgramState *net_dgram_fd_init(NetClientState *peer,
     net_socket_rs_init(&s->rs, net_dgram_rs_finalize, false);
     net_dgram_read_poll(s, true);
 
-    /* mcast: save bound address as dst */
-    if (saddr) {
-        g_assert(s->dest_addr == NULL);
-        s->dest_addr = (struct sockaddr *)saddr;
-        s->dest_len = sizeof(*saddr);
-        qemu_set_info_str(nc, "fd=%d (cloned mcast=%s:%d)", fd,
-                          inet_ntoa(saddr->sin_addr), ntohs(saddr->sin_port));
-    } else {
-        qemu_set_info_str(nc, "fd=%d %s", fd, SocketAddressType_str(sa_type));
-    }
-
     return s;
-
-err:
-    g_free(saddr);
-    closesocket(fd);
-    return NULL;
 }
 
 static int net_dgram_mcast_init(NetClientState *peer,
@@ -381,7 +324,9 @@ static int net_dgram_mcast_init(NetClientState *peer,
             }
             break;
         }
-        case SOCKET_ADDRESS_TYPE_FD:
+        case SOCKET_ADDRESS_TYPE_FD: {
+            int newfd;
+
             fd = monitor_fd_param(monitor_cur(), local->u.fd.str, errp);
             if (fd == -1) {
                 g_free(saddr);
@@ -394,7 +339,42 @@ static int net_dgram_mcast_init(NetClientState *peer,
                                  name, fd);
                 return -1;
             }
+
+            /*
+             * fd passed: multicast: "learn" dest_addr address from bound
+             * address and save it. Because this may be "shared" socket from a
+             * "master" process, datagrams would be recv() by ONLY ONE process:
+             * we must "clone" this dgram socket --jjo
+             */
+
+            saddr = g_new(struct sockaddr_in, 1);
+
+            if (convert_host_port(saddr, local->u.inet.host, local->u.inet.port,
+                                  errp) < 0) {
+                g_free(saddr);
+                closesocket(fd);
+                return -1;
+            }
+
+            /* must be bound */
+            if (saddr->sin_addr.s_addr == 0) {
+                error_setg(errp, "can't setup multicast destination address");
+                g_free(saddr);
+                closesocket(fd);
+                return -1;
+            }
+            /* clone dgram socket */
+            newfd = net_dgram_mcast_create(saddr, NULL, errp);
+            if (newfd < 0) {
+                g_free(saddr);
+                closesocket(fd);
+                return -1;
+            }
+            /* clone newfd to fd, close newfd */
+            dup2(newfd, fd);
+            close(newfd);
             break;
+        }
         default:
             g_free(saddr);
             error_setg(errp, "only support inet or fd type for local");
@@ -402,9 +382,7 @@ static int net_dgram_mcast_init(NetClientState *peer,
         }
     }
 
-    s = net_dgram_fd_init(peer, model, name, fd,
+    s = net_dgram_fd_init(peer, model, name, fd, errp);
-                          local->type == SOCKET_ADDRESS_TYPE_FD,
-                          remote, errp);
     if (!s) {
         g_free(saddr);
         return -1;
@@ -414,8 +392,26 @@ static int net_dgram_mcast_init(NetClientState *peer,
     s->dest_addr = (struct sockaddr *)saddr;
     s->dest_len = sizeof(*saddr);
 
-    qemu_set_info_str(&s->nc, "mcast=%s:%d", inet_ntoa(saddr->sin_addr),
+    if (!local) {
+        qemu_set_info_str(&s->nc, "mcast=%s:%d",
+                          inet_ntoa(saddr->sin_addr),
                           ntohs(saddr->sin_port));
+    } else {
+        switch (local->type) {
+        case SOCKET_ADDRESS_TYPE_INET:
+            qemu_set_info_str(&s->nc, "mcast=%s:%d",
+                              inet_ntoa(saddr->sin_addr),
+                              ntohs(saddr->sin_port));
+            break;
+        case SOCKET_ADDRESS_TYPE_FD:
+            qemu_set_info_str(&s->nc, "fd=%d (cloned mcast=%s:%d)",
+                              fd, inet_ntoa(saddr->sin_addr),
+                              ntohs(saddr->sin_port));
+            break;
+        default:
+            g_assert_not_reached();
+        }
+    }
 
     return 0;
 
@@ -531,7 +527,7 @@ int net_init_dgram(const Netdev *netdev, const char *name,
         return -1;
     }
 
-    s = net_dgram_fd_init(peer, "dgram", name, fd, 0, NULL, errp);
+    s = net_dgram_fd_init(peer, "dgram", name, fd, errp);
     if (!s) {
         return -1;
     }
@@ -550,9 +546,22 @@ int net_init_dgram(const Netdev *netdev, const char *name,
                           inet_ntoa(raddr_in.sin_addr),
                           ntohs(raddr_in.sin_port));
         break;
-    case SOCKET_ADDRESS_TYPE_FD:
+    case SOCKET_ADDRESS_TYPE_FD: {
+        SocketAddress *sa;
+        SocketAddressType sa_type;
+
+        sa = socket_local_address(fd, errp);
+        if (sa) {
+            sa_type = sa->type;
+            qapi_free_SocketAddress(sa);
+
+            qemu_set_info_str(&s->nc, "fd=%d %s", fd,
+                              SocketAddressType_str(sa_type));
+        } else {
             qemu_set_info_str(&s->nc, "fd=%d", fd);
+        }
         break;
+    }
     default:
         g_assert_not_reached();
     }