libs/libc/net: implement socketpair

N/A

Reference here:
https://www.freebsd.org/cgi/man.cgi?apropos=0&sektion=2&query=socketpair&manpath=FreeBSD+7.0-current&format=html

Change-Id: I959b4d661cd436f5d5050baf9e821db84139d482
Signed-off-by: danguanghua <danguanghua@xiaomi.com>

include/sys/socket.h

@@ -379,6 +379,7 @@ extern "C"
 #endif
 
 int socket(int domain, int type, int protocol);
+int socketpair(int domain, int type, int protocol, int sv[2]);
 int bind(int sockfd, FAR const struct sockaddr *addr, socklen_t addrlen);
 int connect(int sockfd, FAR const struct sockaddr *addr, socklen_t addrlen);
 

libs/libc/net/Make.defs

@@ -41,7 +41,7 @@ CSRCS += lib_inetntop.c lib_inetpton.c
 CSRCS += lib_etherntoa.c lib_etheraton.c
 
 ifeq ($(CONFIG_NET),y)
-CSRCS += lib_recvmsg.c lib_sendmsg.c lib_shutdown.c
+CSRCS += lib_recvmsg.c lib_sendmsg.c lib_shutdown.c lib_socketpair.c
 endif
 
 ifeq ($(CONFIG_NET_LOOPBACK),y)

libs/libc/net/lib_socketpair.c

@@ -0,0 +1,186 @@
+/****************************************************************************
+ * libs/libc/net/lib_socketpair.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+/****************************************************************************
+ * Public Type Declarations
+ ****************************************************************************/
+
+union sockaddr_u
+{
+  struct sockaddr addr;
+  struct sockaddr_in inaddr;
+  struct sockaddr_in6 in6addr;
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static inline void init_loop_addr(int domain, FAR union sockaddr_u *addr,
+                                  FAR socklen_t *len)
+{
+  if (domain == AF_INET6)
+    {
+      struct in6_addr init_sin6_addr = IN6ADDR_LOOPBACK_INIT;
+
+      memset(&addr->in6addr, 0, sizeof(addr->in6addr));
+      addr->in6addr.sin6_family = domain;
+      addr->in6addr.sin6_addr = init_sin6_addr;
+      *len = sizeof(addr->in6addr);
+    }
+  else
+    {
+      memset(&addr->inaddr, 0, sizeof(addr->inaddr));
+      addr->inaddr.sin_family = domain;
+      addr->inaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+      *len = sizeof(addr->inaddr);
+    }
+}
+
+static int create_socket(int domain, int type, int protocol,
+                         FAR union sockaddr_u *addr, FAR socklen_t *len)
+{
+  int socketfd;
+
+  socketfd = socket(domain, type, protocol);
+  if (socketfd < 0)
+    {
+      return socketfd;
+    }
+
+  init_loop_addr(domain, addr, len);
+  if (bind(socketfd, &addr->addr, *len) == 0)
+    {
+      if (getsockname(socketfd, &addr->addr, len) == 0)
+        {
+          return socketfd;
+        }
+    }
+
+  close(socketfd);
+  return -1;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: socketpair
+ *
+ * Description:
+ * Create an unbound pair of connected sockets in a specified domain, of a
+ * specified type, under the protocol optionally specified by the protocol
+ * argument. The two sockets shall be identical. The file descriptors used
+ * in referencing the created sockets shall be returned in
+ * sv[0] and sv[1].
+ *
+ ****************************************************************************/
+
+int socketpair(int domain, int type, int protocol, int sv[2])
+{
+  union sockaddr_u addr[2];
+  socklen_t        len;
+
+  if (domain != AF_UNIX && domain != AF_INET && domain != AF_INET6)
+    {
+      set_errno(EAFNOSUPPORT);
+      return -1;
+    }
+
+  if (sv == NULL)
+    {
+      set_errno(EINVAL);
+      return -1;
+    }
+
+  if (domain == AF_UNIX)
+    {
+      domain = AF_INET;
+    }
+
+  sv[0] = create_socket(domain, type, protocol, &addr[0], &len);
+  sv[1] = create_socket(domain, type, protocol, &addr[1], &len);
+  if (sv[0] < 0 || sv[1] < 0)
+    {
+      goto err;
+    }
+
+  if (type == SOCK_DGRAM)
+    {
+      if (connect(sv[0], &addr[1].addr, len) < 0)
+        {
+          goto err;
+        }
+
+      if (connect(sv[1], &addr[0].addr, len) < 0)
+        {
+          goto err;
+        }
+    }
+  else
+    {
+      int listener = sv[0];
+
+      if (listen(listener, 2) < 0)
+        {
+          goto err;
+        }
+
+      if (connect(sv[1], &addr[0].addr, len) < 0)
+        {
+          goto err;
+        }
+
+      sv[0] = accept(listener, &addr[0].addr, &len);
+      close(listener);
+      if (sv[0] < 0)
+        {
+          goto err;
+        }
+    }
+
+  return 0;
+
+err:
+  if (sv[0] != -1)
+    {
+      close(sv[0]);
+    }
+
+  if (sv[1] != -1)
+    {
+      close(sv[1]);
+    }
+
+  return -1;
+}