Add IPv6 to WifiClient (client)

We need to be able to connect to remote servers over IPv6 too,
and thats need different approach in DNS queries and connect().
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:

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

libraries/WiFi/src/WiFiClient.cpp

@@ -210,22 +210,43 @@ int WiFiClient::connect(IPAddress ip, uint16_t port)
 {
     return connect(ip,port,_timeout);
 }
+
 int WiFiClient::connect(IPAddress ip, uint16_t port, int32_t timeout)
 {
+    ip_addr_t dstip;
+    dstip = IPADDR_ANY_TYPE_INIT;
+    IP_ADDR4(&dstip, ip[0], ip[1], ip[2], ip[3]);
+    return connect(dstip, port, timeout);
+}
+
+int WiFiClient::connect(ip_addr_t ip, uint16_t port, int32_t timeout)
+{
+    struct sockaddr_storage serveraddr;
     _timeout = timeout;
-    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    int sockfd = -1;
+
+    if (IP_IS_V6(&ip)) {
+        sockfd = socket(AF_INET6, SOCK_STREAM, 0);
+        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(&ip));
+        tmpaddr->sin6_port = htons(port);
+    }
+    if (sockfd == -1 && IP_IS_V4(&ip)) {
+        sockfd = socket(AF_INET, SOCK_STREAM, 0);
+        struct sockaddr_in *tmpaddr = (struct sockaddr_in *)&serveraddr;
+        memset((char *) tmpaddr, 0, sizeof(struct sockaddr_in));
+        tmpaddr->sin_family = AF_INET;
+        tmpaddr->sin_addr.s_addr = ip4_addr_get_u32(&ip.u_addr.ip4);
+        tmpaddr->sin_port = htons(port);
+    }
     if (sockfd < 0) {
         log_e("socket: %d", errno);
         return 0;
     }
     fcntl( sockfd, F_SETFL, fcntl( sockfd, F_GETFL, 0 ) | O_NONBLOCK );
 
-    uint32_t ip_addr = ip;
-    struct sockaddr_in serveraddr;
-    memset((char *) &serveraddr, 0, sizeof(serveraddr));
-    serveraddr.sin_family = AF_INET;
-    memcpy((void *)&serveraddr.sin_addr.s_addr, (const void *)(&ip_addr), 4);
-    serveraddr.sin_port = htons(port);
     fd_set fdset;
     struct timeval tv;
     FD_ZERO(&fdset);
@@ -294,6 +315,13 @@ int WiFiClient::connect(const char *host, uint16_t port)
 
 int WiFiClient::connect(const char *host, uint16_t port, int32_t timeout)
 {
+    if (WiFiGenericClass::getStatusBits() & WIFI_WANT_IP6_BIT) {
+        ip_addr_t srv6;
+        if(!WiFiGenericClass::hostByName6(host, srv6)){
+            return 0;
+        }
+        return connect(srv6, port, timeout);
+    }
     IPAddress srv((uint32_t)0);
     if(!WiFiGenericClass::hostByName(host, srv)){
         return 0;

libraries/WiFi/src/WiFiClient.h

@@ -24,6 +24,7 @@
 #include "Arduino.h"
 #include "Client.h"
 #include <memory>
+#include "lwip/ip_addr.h"
 
 class WiFiClientSocketHandle;
 class WiFiClientRxBuffer;
@@ -49,6 +50,7 @@ class WiFiClient : public ESPLwIPClient
     WiFiClient();
     WiFiClient(int fd);
     ~WiFiClient();
+    int connect(ip_addr_t ip, uint16_t port, int32_t timeout);
     int connect(IPAddress ip, uint16_t port);
     int connect(IPAddress ip, uint16_t port, int32_t timeout);
     int connect(const char *host, uint16_t port);

libraries/WiFi/src/WiFiGeneric.cpp

@@ -1335,6 +1335,25 @@ static void wifi_dns_found_callback(const char *name, const ip_addr_t *ipaddr, v
     xEventGroupSetBits(_arduino_event_group, WIFI_DNS_DONE_BIT);
 }
 
+/**
+ * IPv6 compatible DNS callback
+ * @param name
+ * @param ipaddr
+ * @param callback_arg
+ */
+static void wifi_dns6_found_callback(const char *name, const ip_addr_t *ipaddr, void *callback_arg)
+{
+    struct dns_api_msg *msg = (struct dns_api_msg *)callback_arg;
+
+    if(ipaddr && !msg->result) {
+        msg->ip_addr = *ipaddr;
+        msg->result = 1;
+    } else {
+        msg->result = -1;
+    }
+    xEventGroupSetBits(_arduino_event_group, WIFI_DNS_DONE_BIT);
+}
+
 /**
  * Resolve the given hostname to an IP address.
  * @param aHostname     Name to be resolved
@@ -1362,6 +1381,36 @@ int WiFiGenericClass::hostByName(const char* aHostname, IPAddress& aResult)
     return (uint32_t)aResult != 0;
 }
 
+/**
+ * Resolve the given hostname to an IP6 address.
+ * @param aHostname     Name to be resolved
+ * @param aResult       IPv6Address structure to store the returned IP address
+ * @return 1 if aHostname was successfully converted to an IP address,
+ *          else error code
+ */
+int WiFiGenericClass::hostByName6(const char* aHostname, ip_addr_t& aResult)
+{
+    ip_addr_t addr;
+    struct dns_api_msg arg;
+
+    memset(&arg, 0x0, sizeof(arg));
+    waitStatusBits(WIFI_DNS_IDLE_BIT, 16000);
+    clearStatusBits(WIFI_DNS_IDLE_BIT | WIFI_DNS_DONE_BIT);
+
+    err_t err = dns_gethostbyname_addrtype(aHostname, &addr, &wifi_dns6_found_callback,
+                &arg, LWIP_DNS_ADDRTYPE_IPV6_IPV4);
+    if(err == ERR_OK) {
+        aResult = addr;
+    } else if(err == ERR_INPROGRESS) {
+        waitStatusBits(WIFI_DNS_DONE_BIT, 15000);  //real internal timeout in lwip library is 14[s]
+        clearStatusBits(WIFI_DNS_DONE_BIT);
+        if (arg.result == 1)
+            aResult = arg.ip_addr;
+    }
+    setStatusBits(WIFI_DNS_IDLE_BIT);
+    return (uint32_t)err == ERR_OK || (err == ERR_INPROGRESS && arg.result == 1);
+}
+
 IPAddress WiFiGenericClass::calculateNetworkID(IPAddress ip, IPAddress subnet) {
 	IPAddress networkID;
 

libraries/WiFi/src/WiFiGeneric.h

@@ -152,6 +152,11 @@ typedef enum {
 	WIFI_TX_ANT_AUTO
 } wifi_tx_ant_t;
 
+struct dns_api_msg {
+    ip_addr_t ip_addr;
+    int result;
+};
+
 class WiFiGenericClass
 {
   public:
@@ -210,6 +215,7 @@ class WiFiGenericClass
 
   public:
     static int hostByName(const char *aHostname, IPAddress &aResult);
+    static int hostByName6(const char *aHostname, ip_addr_t &aResult);
 
     static IPAddress calculateNetworkID(IPAddress ip, IPAddress subnet);
     static IPAddress calculateBroadcast(IPAddress ip, IPAddress subnet);