Worked on IPv6-only stack:

- prepared DNS;
- fixed compiling ppp.c

src/core/dns.c

@@ -113,7 +113,11 @@ static u16_t dns_txid;
 
 /** DNS server IP address */
 #ifndef DNS_SERVER_ADDRESS
+#if LWIP_IPV4
 #define DNS_SERVER_ADDRESS(ipaddr)        ip_addr_set_ip4_u32(ipaddr, ipaddr_addr("208.67.222.222")) /* resolver1.opendns.com */
+#else
+#define DNS_SERVER_ADDRESS(ipaddr)        ipaddr_aton("2001:4860:4860::8888", ipaddr)
+#endif
 #endif
 
 /** DNS server port address */
@@ -449,17 +453,21 @@ dns_init_local()
  * Scans the local host-list for a hostname.
  *
  * @param hostname Hostname to look for in the local host-list
- * @return The first IP address for the hostname in the local host-list or
+ * @param addr the first IP address for the hostname in the local host-list or
  *         IPADDR_NONE if not found.
+ * @return ERR_OK if found, ERR_ARG if not found
  */
-static u32_t
+static err_t
-dns_lookup_local(const char *hostname)
+dns_lookup_local(const char *hostname, ip_addr_t *addr)
 {
 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
   struct local_hostlist_entry *entry = local_hostlist_dynamic;
   while(entry != NULL) {
     if (LWIP_DNS_STRICMP(entry->name, hostname) == 0) {
-      return ip_addr_get_ip4_u32(&entry->addr);
+      if (addr) {
+        ip_addr_copy(*addr, entry->addr);
+      }
+      return ERR_OK;
     }
     entry = entry->next;
   }
@@ -467,11 +475,14 @@ dns_lookup_local(const char *hostname)
   int i;
   for (i = 0; i < sizeof(local_hostlist_static) / sizeof(struct local_hostlist_entry); i++) {
     if (LWIP_DNS_STRICMP(local_hostlist_static[i].name, hostname) == 0) {
-      return ip_addr_get_ip4_u32(&local_hostlist_static[i].addr);
+      if (addr) {
+        ip_addr_copy(*addr, local_hostlist_static[i].addr);
+      }
+      return ERR_OK;
     }
   }
 #endif /* DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
-  return IPADDR_NONE;
+  return ERR_ARG;
 }
 
 #if DNS_LOCAL_HOSTLIST_IS_DYNAMIC
@@ -550,20 +561,20 @@ dns_local_addhost(const char *hostname, const ip_addr_t *addr)
  * for a hostname.
  *
  * @param name the hostname to look up
- * @return the hostname's IP address, as u32_t (instead of ip_addr_t to
+ * @param addr the hostname's IP address, as u32_t (instead of ip_addr_t to
  *         better check for failure: != IPADDR_NONE) or IPADDR_NONE if the hostname
  *         was not found in the cached dns_table.
+ * @return ERR_OK if found, ERR_ARG if not found
  */
-static u32_t
+static err_t
-dns_lookup(const char *name)
+dns_lookup(const char *name, ip_addr_t *addr)
 {
   u8_t i;
 #if DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN)
-  u32_t addr;
 #endif /* DNS_LOCAL_HOSTLIST || defined(DNS_LOOKUP_LOCAL_EXTERN) */
 #if DNS_LOCAL_HOSTLIST
-  if ((addr = dns_lookup_local(name)) != IPADDR_NONE) {
+  if (dns_lookup_local(name, addr) == ERR_OK) {
-    return addr;
+    return ERR_OK;
   }
 #endif /* DNS_LOCAL_HOSTLIST */
 #ifdef DNS_LOOKUP_LOCAL_EXTERN
@@ -577,13 +588,16 @@ dns_lookup(const char *name)
     if ((dns_table[i].state == DNS_STATE_DONE) &&
         (LWIP_DNS_STRICMP(name, dns_table[i].name) == 0)) {
       LWIP_DEBUGF(DNS_DEBUG, ("dns_lookup: \"%s\": found = ", name));
-      ip4_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
+      ip_addr_debug_print(DNS_DEBUG, &(dns_table[i].ipaddr));
       LWIP_DEBUGF(DNS_DEBUG, ("\n"));
-      return ip_addr_get_ip4_u32(&dns_table[i].ipaddr);
+      if (addr) {
+        ip_addr_copy(*addr, dns_table[i].ipaddr);
+      }
+      return ERR_OK;
     }
   }
 
-  return IPADDR_NONE;
+  return ERR_ARG;
 }
 
 /**
@@ -1058,6 +1072,7 @@ dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr,
 
           /* Check for IP address type and Internet class. Others are discarded. */
           pbuf_copy_partial(p, &ans, SIZEOF_DNS_ANSWER, res_idx);
+#if LWIP_IPV4
           if((ans.type == PP_HTONS(DNS_RRTYPE_A)) && (ans.cls == PP_HTONS(DNS_RRCLASS_IN)) &&
              (ans.len == PP_HTONS(sizeof(ip4_addr_t))) ) {
             res_idx += SIZEOF_DNS_ANSWER;
@@ -1082,7 +1097,10 @@ dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr,
             }
             /* deallocate memory and return */
             goto memerr;
-          } else {
+          } else
+#endif /* LWIP_IPV4 */
+          {
+            /* @todo: parse IPv6 answers */
             res_idx += SIZEOF_DNS_ANSWER + htons(ans.len);
           }
           --nanswers;
@@ -1100,7 +1118,9 @@ dns_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr,
 responseerr:
   /* ERROR: call specified callback function with NULL as name to indicate an error */
   dns_call_found(entry_idx, NULL);
+#if LWIP_IPV4
 flushentry:
+#endif /* LWIP_IPV4 */
   /* flush this entry */
   dns_table[entry_idx].state = DNS_STATE_UNUSED;
 
@@ -1257,7 +1277,6 @@ err_t
 dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback found,
                   void *callback_arg)
 {
-  u32_t ipaddr;
   size_t hostnamelen;
   /* not initialized or no valid server yet, or invalid addr pointer
    * or invalid hostname or invalid hostname length */
@@ -1286,13 +1305,11 @@ dns_gethostbyname(const char *hostname, ip_addr_t *addr, dns_found_callback foun
 #endif /* LWIP_HAVE_LOOPIF */
 
   /* host name already in octet notation? set ip addr and return ERR_OK */
-  ipaddr = ipaddr_addr(hostname);
+  if (ipaddr_aton(hostname, addr)) {
-  if (ipaddr == IPADDR_NONE) {
+    return ERR_OK;
-    /* already have this address cached? */
-    ipaddr = dns_lookup(hostname);
   }
-  if (ipaddr != IPADDR_NONE) {
+  /* already have this address cached? */
-    ip_addr_set_ip4_u32(addr, ipaddr);
+  if(dns_lookup(hostname, addr) == ERR_OK) {
     return ERR_OK;
   }
 

src/include/lwip/dns.h

@@ -36,13 +36,7 @@
 
 #include "lwip/opt.h"
 
-/* @todo/@fixme: implement IPV6 support for DNS (see task #12243) */
+#if LWIP_DNS
-#if !LWIP_IPV4 && LWIP_DNS
-/* init.c/timers.c compatibility until task #12243 is done: */
-#define dns_init()
-#define dns_tmr()
-#define DNS_TMR_INTERVAL          1000
-#elif LWIP_DNS /* don't build if not configured for use in lwipopts.h */
 
 #ifdef __cplusplus
 extern "C" {

src/netif/ppp/ppp.c

@@ -181,7 +181,9 @@ const struct protent* const protocols[] = {
 /* Prototypes for procedures local to this file. */
 static void ppp_do_connect(void *arg);
 static err_t ppp_netif_init_cb(struct netif *netif);
+#if PPP_IPV4_SUPPORT
 static err_t ppp_netif_output_ip4(struct netif *netif, struct pbuf *pb, const ip4_addr_t *ipaddr);
+#endif /* PPP_IPV4_SUPPORT */
 #if PPP_IPV6_SUPPORT
 static err_t ppp_netif_output_ip6(struct netif *netif, struct pbuf *pb, const ip6_addr_t *ipaddr);
 #endif /* PPP_IPV6_SUPPORT */
@@ -410,8 +412,10 @@ static void ppp_do_connect(void *arg) {
 static err_t ppp_netif_init_cb(struct netif *netif) {
   netif->name[0] = 'p';
   netif->name[1] = 'p';
+#if PPP_IPV4_SUPPORT
   /* FIXME: change that when netif_null_output_ip4() will materialize */
   netif->output = ppp_netif_output_ip4;
+#endif /* PPP_IPV4_SUPPORT */
 #if PPP_IPV6_SUPPORT
   netif->output_ip6 = ppp_netif_output_ip6;
 #endif /* PPP_IPV6_SUPPORT */
@@ -423,6 +427,7 @@ static err_t ppp_netif_init_cb(struct netif *netif) {
   return ERR_OK;
 }
 
+#if PPP_IPV4_SUPPORT
 /*
  * Send an IPv4 packet on the given connection.
  */
@@ -448,6 +453,7 @@ static err_t ppp_netif_output_ip4(struct netif *netif, struct pbuf *pb, const ip
   return ERR_IF;
 #endif /* PPP_IPV4_SUPPORT */
 }
+#endif /* PPP_IPV4_SUPPORT */
 
 #if PPP_IPV6_SUPPORT
 /*
@@ -556,7 +562,10 @@ ppp_pcb *ppp_new(struct netif *pppif, ppp_link_status_cb_fn link_status_cb, void
   pcb->settings.fsm_max_nak_loops = FSM_DEFMAXNAKLOOPS;
 
   pcb->netif = pppif;
-  if (!netif_add(pcb->netif, IP4_ADDR_ANY, IP4_ADDR_BROADCAST, IP4_ADDR_ANY,
+  if (!netif_add(pcb->netif,
+#if LWIP_IPV4
+                 IP4_ADDR_ANY, IP4_ADDR_BROADCAST, IP4_ADDR_ANY,
+#endif /* LWIP_IPV4 */
                  (void *)pcb, ppp_netif_init_cb, NULL)) {
     memp_free(MEMP_PPP_PCB, pcb);
     PPPDEBUG(LOG_ERR, ("ppp_new: netif_add failed\n"));
@@ -681,10 +690,12 @@ void ppp_input(ppp_pcb *pcb, struct pbuf *pb) {
 
   switch(protocol) {
 
+#if PPP_IPV4_SUPPORT
     case PPP_IP:            /* Internet Protocol */
       PPPDEBUG(LOG_INFO, ("ppp_input[%d]: ip in pbuf len=%d\n", pcb->netif->num, pb->tot_len));
       ip4_input(pb, pcb->netif);
       return;
+#endif /* PPP_IPV4_SUPPORT */
 
 #if PPP_IPV6_SUPPORT
     case PPP_IPV6:          /* Internet Protocol Version 6 */
@@ -1154,6 +1165,7 @@ int get_loop_output(void) {
 }
 #endif /* DEMAND_SUPPORT */
 
+#if PPP_IPV4_SUPPORT
 /********************************************************************
  *
  * Return user specified netmask, modified by any mask we might determine
@@ -1189,6 +1201,7 @@ u32_t get_mask(u32_t addr) {
   LWIP_UNUSED_ARG(addr);
   return IPADDR_BROADCAST;
 }
+#endif /* PPP_IPV4_SUPPORT */
 
 
 #if PPP_PROTOCOLNAME