IPv6 support for WiFiClientSecure / ssl_client

Similar to implementation in WiFiClient, we implement WiFiClientSecure
with IPv6 support with minimal differences.

As i'm trying to keep maximum compatibility, i introduce different
behaviour if IPv6 is enabled, and backward compatible (as much as possible),
if IPv6 is not enabled.
IN future when IPv6 functions are tested well enough, it can be simplified.

This implementation tested on esp32 in following scenarios using BasicHttpClient
using https:// urls:

IPv6 true:
IPv6 only website (caveat 1) - OK
Website with A and AAAA is present (caveat 1) - OK
IPv4 only website - OK

IPv6 not enabled:
IPv6 only website - wont open (expected)
Website with A and AAAA is present - OK, opens over IPv4
IPv4 only website - OK

caveat 1 - sometimes SLAAC is slower than DHCPv4, so we might have
status WL_CONNECTED, but IPv6 global scope is not ready yet.

Signed-off-by: Denys Fedoryshchenko <[email protected]>

Author: nuclearcat

Diff for: libraries/WiFiClientSecure/src/ssl_client.cpp

@@ -60,31 +60,53 @@ int start_ssl_client(sslclient_context *ssl_client, const char *host, uint32_t p
     int ret, flags;
     int enable = 1;
     log_v("Free internal heap before TLS %u", ESP.getFreeHeap());
+    bool is_ipv4 = true;
 
     if (rootCABuff == NULL && pskIdent == NULL && psKey == NULL && !insecure && !useRootCABundle) {
         return -1;
     }
 
     log_v("Starting socket");
     ssl_client->socket = -1;
+    struct sockaddr_storage serveraddr;
+    ip_addr_t dstip;
+    IPAddress srv((uint32_t)0);
+
+    if (WiFiGenericClass::getStatusBits() & WIFI_WANT_IP6_BIT) {
+        ip_addr_t srv6;
+        if(!WiFiGenericClass::hostByName6(host, srv6)){
+            return -1;
+        }
+        if (IP_IS_V6(&srv6)) {
+            is_ipv4 = false;
+            ssl_client->socket = lwip_socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
+            struct sockaddr_in6 *tmpaddr = (struct sockaddr_in6 *)&serveraddr;
+            memset((char *) tmpaddr, 0, sizeof(struct sockaddr_in6));
+            tmpaddr->sin6_family = AF_INET6;
+            inet6_addr_from_ip6addr(&tmpaddr->sin6_addr, ip_2_ip6(&srv6));
+            tmpaddr->sin6_port = htons(port);
+        } else {
+            srv = ip4_addr_get_u32(&srv6.u_addr.ip4);
+        }
+    } else {
+        if(!WiFiGenericClass::hostByName(host, srv))
+            return -1;
+    }
+    if (is_ipv4 == true) {
+        ssl_client->socket = lwip_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+        struct sockaddr_in *serv_addr = (struct sockaddr_in*)&serveraddr;
+        memset(serv_addr, 0, sizeof(serv_addr));
+        serv_addr->sin_family = AF_INET;
+        serv_addr->sin_addr.s_addr = srv;
+        serv_addr->sin_port = htons(port);
+    }
 
-    ssl_client->socket = lwip_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
     if (ssl_client->socket < 0) {
         log_e("ERROR opening socket");
         return ssl_client->socket;
     }
 
-    IPAddress srv((uint32_t)0);
-    if(!WiFiGenericClass::hostByName(host, srv)){
-        return -1;
-    }
-
     fcntl( ssl_client->socket, F_SETFL, fcntl( ssl_client->socket, F_GETFL, 0 ) | O_NONBLOCK );
-    struct sockaddr_in serv_addr;
-    memset(&serv_addr, 0, sizeof(serv_addr));
-    serv_addr.sin_family = AF_INET;
-    serv_addr.sin_addr.s_addr = srv;
-    serv_addr.sin_port = htons(port);
 
     if(timeout <= 0){
         timeout = 30000; // Milli seconds.
@@ -97,7 +119,7 @@ int start_ssl_client(sslclient_context *ssl_client, const char *host, uint32_t p
     tv.tv_sec = timeout / 1000;
     tv.tv_usec = (timeout % 1000) * 1000;
 
-    int res = lwip_connect(ssl_client->socket, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
+    int res = lwip_connect(ssl_client->socket, (struct sockaddr*)&serveraddr, sizeof(serveraddr));
     if (res < 0 && errno != EINPROGRESS) {
         log_e("connect on fd %d, errno: %d, \"%s\"", ssl_client->socket, errno, strerror(errno));
         close(ssl_client->socket);