From 9366c0eaabde4ef2744ab93d40e96def453925dc Mon Sep 17 00:00:00 2001
From: Dirk Ziegelmeier <dirk@ziegelmeier.net>
Date: Thu, 17 Nov 2016 12:41:00 +0100
Subject: [PATCH] I decided to keep the "complexity" of handling IPv6 mapped
 IPv4 addresses out of netconn API. Only socket API understands this address
 type now.

---
 src/api/api_lib.c | 70 +++++++++++++----------------------------------
 src/api/sockets.c | 35 +++++++++++++++++++++++-
 2 files changed, 53 insertions(+), 52 deletions(-)

diff --git a/src/api/api_lib.c b/src/api/api_lib.c
index ae366ad4..31be589c 100644
--- a/src/api/api_lib.c
+++ b/src/api/api_lib.c
@@ -259,33 +259,22 @@ netconn_bind(struct netconn *conn, const ip_addr_t *addr, u16_t port)
     addr = IP4_ADDR_ANY;
   }
   
-  {
 #if LWIP_IPV4 && LWIP_IPV6
-    ip_addr_t ipaddr;
-
-    /* "Socket API like" dual-stack support: If IP to bind to is IP6_ADDR_ANY,
-    * and NETCONN_FLAG_IPV6_V6ONLY is 0, use IP_ANY_TYPE to bind
-    */
-    if ((netconn_get_ipv6only(conn) == 0) &&
-       ip_addr_cmp(addr, IP6_ADDR_ANY)) {
-      addr = IP_ANY_TYPE;
-    }
-
-    /* Dual-stack: Unmap IPv6 mapped IPv4 addresses */
-    if (IP_IS_V6(addr) && ip6_addr_isipv6mappedipv4(ip_2_ip6(addr))) {
-      unmap_ipv6_mapped_ipv4(ip_2_ip4(&ipaddr), ip_2_ip6(addr));
-      IP_SET_TYPE_VAL(ipaddr, IPADDR_TYPE_V4);
-      addr = &ipaddr;
-    }
+  /* "Socket API like" dual-stack support: If IP to bind to is IP6_ADDR_ANY,
+   * and NETCONN_FLAG_IPV6_V6ONLY is 0, use IP_ANY_TYPE to bind
+   */
+  if ((netconn_get_ipv6only(conn) == 0) &&
+     ip_addr_cmp(addr, IP6_ADDR_ANY)) {
+    addr = IP_ANY_TYPE;
+  }
 #endif /* LWIP_IPV4 && LWIP_IPV6 */
 
-    API_MSG_VAR_ALLOC(msg);
-    API_MSG_VAR_REF(msg).conn = conn;
-    API_MSG_VAR_REF(msg).msg.bc.ipaddr = API_MSG_VAR_REF(addr);
-    API_MSG_VAR_REF(msg).msg.bc.port = port;
-    err = netconn_apimsg(lwip_netconn_do_bind, &API_MSG_VAR_REF(msg));
-    API_MSG_VAR_FREE(msg);
-  }
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).conn = conn;
+  API_MSG_VAR_REF(msg).msg.bc.ipaddr = API_MSG_VAR_REF(addr);
+  API_MSG_VAR_REF(msg).msg.bc.port = port;
+  err = netconn_apimsg(lwip_netconn_do_bind, &API_MSG_VAR_REF(msg));
+  API_MSG_VAR_FREE(msg);
 
   return err;
 }
@@ -312,25 +301,12 @@ netconn_connect(struct netconn *conn, const ip_addr_t *addr, u16_t port)
     addr = IP4_ADDR_ANY;
   }
 
-  {
-#if LWIP_IPV4 && LWIP_IPV6
-    ip_addr_t ipaddr;
-
-    /* Dual-stack: Unmap IPv6 mapped IPv4 addresses */
-    if (IP_IS_V6(addr) && ip6_addr_isipv6mappedipv4(ip_2_ip6(addr))) {
-      unmap_ipv6_mapped_ipv4(ip_2_ip4(&ipaddr), ip_2_ip6(addr));
-      IP_SET_TYPE_VAL(ipaddr, IPADDR_TYPE_V4);
-      addr = &ipaddr;
-    }
-#endif /* LWIP_IPV4 && LWIP_IPV6 */
-
-    API_MSG_VAR_ALLOC(msg);
-    API_MSG_VAR_REF(msg).conn = conn;
-    API_MSG_VAR_REF(msg).msg.bc.ipaddr = API_MSG_VAR_REF(addr);
-    API_MSG_VAR_REF(msg).msg.bc.port = port;
-    err = netconn_apimsg(lwip_netconn_do_connect, &API_MSG_VAR_REF(msg));
-    API_MSG_VAR_FREE(msg);
-  }
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).conn = conn;
+  API_MSG_VAR_REF(msg).msg.bc.ipaddr = API_MSG_VAR_REF(addr);
+  API_MSG_VAR_REF(msg).msg.bc.port = port;
+  err = netconn_apimsg(lwip_netconn_do_connect, &API_MSG_VAR_REF(msg));
+  API_MSG_VAR_FREE(msg);
 
   return err;
 }
@@ -731,14 +707,6 @@ netconn_send(struct netconn *conn, struct netbuf *buf)
   LWIP_ERROR("netconn_send: invalid conn",  (conn != NULL), return ERR_ARG;);
 
   LWIP_DEBUGF(API_LIB_DEBUG, ("netconn_send: sending %"U16_F" bytes\n", buf->p->tot_len));
-        
-#if LWIP_IPV4 && LWIP_IPV6
-  /* Dual-stack: Unmap IPv6 mapped IPv4 addresses */
-  if (IP_IS_V6_VAL(buf->addr) && ip6_addr_isipv6mappedipv4(ip_2_ip6(&buf->addr))) {
-    unmap_ipv6_mapped_ipv4(ip_2_ip4(&buf->addr), ip_2_ip6(&buf->addr));
-    IP_SET_TYPE_VAL(buf->addr, IPADDR_TYPE_V4);
-  }
-#endif /* LWIP_IPV4 && LWIP_IPV6 */
 
   API_MSG_VAR_ALLOC(msg);
   API_MSG_VAR_REF(msg).conn = conn;
diff --git a/src/api/sockets.c b/src/api/sockets.c
index 22f3acd6..2db0949d 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -584,6 +584,14 @@ lwip_bind(int s, const struct sockaddr *name, socklen_t namelen)
   ip_addr_debug_print_val(SOCKETS_DEBUG, local_addr);
   LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", local_port));
 
+#if LWIP_IPV4 && LWIP_IPV6
+  /* Dual-stack: Unmap IPv6 mapped IPv4 addresses */
+  if (IP_IS_V6_VAL(local_addr) && ip6_addr_isipv6mappedipv4(ip_2_ip6(&local_addr))) {
+    unmap_ipv6_mapped_ipv4(ip_2_ip4(&local_addr), ip_2_ip6(&local_addr));
+    IP_SET_TYPE_VAL(local_addr, IPADDR_TYPE_V4);
+  }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
   err = netconn_bind(sock->conn, &local_addr, local_port);
 
   if (err != ERR_OK) {
@@ -668,6 +676,14 @@ lwip_connect(int s, const struct sockaddr *name, socklen_t namelen)
     ip_addr_debug_print_val(SOCKETS_DEBUG, remote_addr);
     LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", remote_port));
 
+#if LWIP_IPV4 && LWIP_IPV6
+    /* Dual-stack: Unmap IPv6 mapped IPv4 addresses */
+    if (IP_IS_V6_VAL(remote_addr) && ip6_addr_isipv6mappedipv4(ip_2_ip6(&remote_addr))) {
+      unmap_ipv6_mapped_ipv4(ip_2_ip4(&remote_addr), ip_2_ip6(&remote_addr));
+      IP_SET_TYPE_VAL(remote_addr, IPADDR_TYPE_V4);
+    }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
     err = netconn_connect(sock->conn, &remote_addr, remote_port);
   }
 
@@ -1075,6 +1091,14 @@ lwip_sendmsg(int s, const struct msghdr *msg, int flags)
 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
 
     if (err == ERR_OK) {
+#if LWIP_IPV4 && LWIP_IPV6
+      /* Dual-stack: Unmap IPv6 mapped IPv4 addresses */
+      if (IP_IS_V6_VAL(chain_buf->addr) && ip6_addr_isipv6mappedipv4(ip_2_ip6(&chain_buf->addr))) {
+        unmap_ipv6_mapped_ipv4(ip_2_ip4(&chain_buf->addr), ip_2_ip6(&chain_buf->addr));
+        IP_SET_TYPE_VAL(chain_buf->addr, IPADDR_TYPE_V4);
+      }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
       /* send the data */
       err = netconn_send(sock->conn, chain_buf);
     }
@@ -1165,6 +1189,14 @@ lwip_sendto(int s, const void *data, size_t size, int flags,
   err = netbuf_ref(&buf, data, short_size);
 #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
   if (err == ERR_OK) {
+#if LWIP_IPV4 && LWIP_IPV6
+    /* Dual-stack: Unmap IPv6 mapped IPv4 addresses */
+    if (IP_IS_V6_VAL(buf.addr) && ip6_addr_isipv6mappedipv4(ip_2_ip6(&buf.addr))) {
+      unmap_ipv6_mapped_ipv4(ip_2_ip4(&buf.addr), ip_2_ip6(&buf.addr));
+      IP_SET_TYPE_VAL(buf.addr, IPADDR_TYPE_V4);
+    }
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+
     /* send the data */
     err = netconn_send(sock->conn, &buf);
   }
@@ -1722,7 +1754,8 @@ lwip_getaddrname(int s, struct sockaddr *name, socklen_t *namelen, u8_t local)
 
 #if LWIP_IPV4 && LWIP_IPV6
   /* Dual-stack: Map IPv4 addresses to IPv6 mapped IPv4 */
-  if (NETCONNTYPE_ISIPV6(netconn_type(sock->conn)) && IP_IS_V4_VAL(naddr)) {
+  if (NETCONNTYPE_ISIPV6(netconn_type(sock->conn)) &&
+      IP_IS_V4_VAL(naddr)) {
     ip4_2_ipv6_mapped_ipv4(ip_2_ip6(&naddr), ip_2_ip4(&naddr));
     IP_SET_TYPE_VAL(naddr, IPADDR_TYPE_V6);
   }