- Andreas Schuldei improved Phil Blundell's patch for IPv6 using c-ares, and I

edited it slightly. Now you should be able to use IPv6 addresses fine even
  with libcurl built to use c-ares.

CHANGES

@@ -6,6 +6,11 @@
 
                                   Changelog
 
+Daniel Stenberg (9 Jul 2008)
+- Andreas Schuldei improved Phil Blundell's patch for IPv6 using c-ares, and I
+  edited it slightly. Now you should be able to use IPv6 addresses fine even
+  with libcurl built to use c-ares.
+
 Daniel Fandrich (9 Jul 2008)
 - Fixed an OOM handling problem that cause test 11 to fail the torture test.
 

RELEASE-NOTES

@@ -31,6 +31,7 @@ This release includes the following bugfixes:
  o range numbers could be made to wrongly get output as signed
  o unexpected 1xx responses hung transfers
  o FTP transfers segfault when using different CURLOPT_FTP_FILEMETHOD
+ o c-ares powered libcurls can resolve/use IPv6 addresses
 
 This release includes the following known bugs:
 
@@ -50,7 +51,7 @@ advice from friends like these:
  Lenny Rachitsky, Axel Tillequin, Arnaud Ebalard, Yang Tse, Dan Fandrich,
  Rob Crittenden, Dengminwen, Christopher Palow, Hans-Jurgen May,
  Phil Pellouchoud, Eduard Bloch, John Lightsey, Stephen Collyer, Tor Arntsen,
- Rolland Dudemaine, Phil Blundell, Scott Barrett
+ Rolland Dudemaine, Phil Blundell, Scott Barrett, Andreas Schuldei
 
 
         Thanks! (and sorry if I forgot to mention someone)

lib/hostares.c

@@ -297,6 +297,70 @@ CURLcode Curl_wait_for_resolv(struct connectdata *conn,
   return rc;
 }
 
+#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
+/*
+ * Curl_ip2addr6() takes an ipv6 internet address as input parameter
+ * together with a pointer to the string version of the address, and it
+ * returns a Curl_addrinfo chain filled in correctly with information for this
+ * address/host.
+ *
+ * The input parameters ARE NOT checked for validity but they are expected
+ * to have been checked already when this is called.
+ */
+Curl_addrinfo *Curl_ip2addr6(struct in6_addr *in,
+			     const char *hostname, int port)
+{
+  Curl_addrinfo *ai;
+
+#if defined(VMS) &&  defined(__INITIAL_POINTER_SIZE) && \
+  (__INITIAL_POINTER_SIZE == 64)
+#pragma pointer_size save
+#pragma pointer_size short
+#pragma message disable PTRMISMATCH
+#endif
+
+  struct hostent *h;
+  struct in6_addr *addrentry;
+  struct namebuf6 {
+    struct hostent hostentry;
+    char *h_addr_list[2];
+    struct in6_addr addrentry;
+    char hostname[1];
+  };
+  struct namebuf6 *buf = malloc(sizeof (struct namebuf6) + strlen(hostname));
+
+  if(!buf)
+    return NULL;
+
+  h = &buf->hostentry;
+  h->h_addr_list = &buf->h_addr_list[0];
+  addrentry = &buf->addrentry;
+  memcpy(addrentry, in, sizeof (*in));
+  h->h_addr_list[0] = (char*)addrentry;
+  h->h_addr_list[1] = NULL; /* terminate list of entries */
+  h->h_name = &buf->hostname[0];
+  h->h_aliases = NULL;
+  h->h_addrtype = AF_INET6;
+
+  /* Now store the dotted version of the address */
+  strcpy (h->h_name, hostname);
+
+#if defined(VMS) && defined(__INITIAL_POINTER_SIZE) && \
+  (__INITIAL_POINTER_SIZE == 64)
+#pragma pointer_size restore
+#pragma message enable PTRMISMATCH
+#endif
+
+  ai = Curl_he2ai(h, port);
+
+  free(buf);
+
+  return ai;
+}
+#endif /* CURLRES_IPV6 */
+
+
+
 /*
  * Curl_getaddrinfo() - when using ares
  *
@@ -313,7 +377,10 @@ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
   char *bufp;
   struct SessionHandle *data = conn->data;
   in_addr_t in = inet_addr(hostname);
-
+  int family = PF_INET;
+#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
+  struct in6_addr in6;
+#endif /* CURLRES_IPV6 */
   *waitp = FALSE;
 
   if(in != CURL_INADDR_NONE) {
@@ -321,6 +388,23 @@ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
     return Curl_ip2addr(in, hostname, port);
   }
 
+#ifdef ENABLE_IPV6 /* CURLRES_IPV6 */
+  if (inet_pton (AF_INET6, hostname, &in6) > 0) {
+    /* This must be an IPv6 address literal.  */
+    return Curl_ip2addr6(&in6, hostname, port);
+  }
+
+  switch(data->set.ip_version) {
+  case CURL_IPRESOLVE_V4:
+    family = PF_INET;
+    break;
+  default: /* by default we try ipv6, as PF_UNSPEC isn't supported by (c-)ares */
+  case CURL_IPRESOLVE_V6:
+    family = PF_INET6;
+    break;
+  }
+#endif /* CURLRES_IPV6 */
+
   bufp = strdup(hostname);
 
   if(bufp) {
@@ -332,7 +416,7 @@ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
     conn->async.dns = NULL;   /* clear */
 
     /* areschannel is already setup in the Curl_open() function */
-    ares_gethostbyname(data->state.areschannel, hostname, PF_INET,
+    ares_gethostbyname(data->state.areschannel, hostname, family,
                        (ares_host_callback)Curl_addrinfo4_callback, conn);
 
     *waitp = TRUE; /* please wait for the response */

lib/hostip.c

@@ -545,7 +545,8 @@ Curl_addrinfo *Curl_addrinfo_copy(const void *org, int port)
 #endif /* CURLRES_ADDRINFO_COPY */
 
 /***********************************************************************
- * Only for plain-ipv4 and c-ares builds
+ * Only for plain-ipv4 and c-ares builds (NOTE: c-ares builds can be IPv6
+ * enabled)
  **********************************************************************/
 
 #if defined(CURLRES_IPV4) || defined(CURLRES_ARES)
@@ -630,6 +631,118 @@ Curl_addrinfo *Curl_ip2addr(in_addr_t num, const char *hostname, int port)
 
   return ai;
 }
+
+/*
+ * Curl_he2ai() translates from a hostent struct to a Curl_addrinfo struct.
+ * The Curl_addrinfo is meant to work like the addrinfo struct does for IPv6
+ * stacks, but for all hosts and environments.
+ *
+ *   Curl_addrinfo defined in "lib/hostip.h"
+ *
+ *     struct Curl_addrinfo {
+ *       int                   ai_flags;
+ *       int                   ai_family;
+ *       int                   ai_socktype;
+ *       int                   ai_protocol;
+ *       socklen_t             ai_addrlen;   * Follow rfc3493 struct addrinfo *
+ *       char                 *ai_canonname;
+ *       struct sockaddr      *ai_addr;
+ *       struct Curl_addrinfo *ai_next;
+ *     };
+ *
+ *   hostent defined in <netdb.h>
+ *
+ *     struct hostent {
+ *       char    *h_name;
+ *       char    **h_aliases;
+ *       int     h_addrtype;
+ *       int     h_length;
+ *       char    **h_addr_list;
+ *     };
+ *
+ *   for backward compatibility:
+ *
+ *     #define h_addr  h_addr_list[0]
+ */
+
+Curl_addrinfo *Curl_he2ai(const struct hostent *he, int port)
+{
+  Curl_addrinfo *ai;
+  Curl_addrinfo *prevai = NULL;
+  Curl_addrinfo *firstai = NULL;
+  struct sockaddr_in *addr;
+#ifdef CURLRES_IPV6
+  struct sockaddr_in6 *addr6;
+#endif /* CURLRES_IPV6 */
+  int i;
+  struct in_addr *curr;
+
+  if(!he)
+    /* no input == no output! */
+    return NULL;
+
+  for(i=0; (curr = (struct in_addr *)he->h_addr_list[i]) != NULL; i++) {
+
+    int ss_size;
+#ifdef CURLRES_IPV6
+    if (he->h_addrtype == AF_INET6)
+      ss_size = sizeof (struct sockaddr_in6);
+    else
+#endif /* CURLRES_IPV6 */
+      ss_size = sizeof (struct sockaddr_in);
+
+    ai = calloc(1, sizeof(Curl_addrinfo) + ss_size);
+
+    if(!ai)
+      break;
+
+    if(!firstai)
+      /* store the pointer we want to return from this function */
+      firstai = ai;
+
+    if(prevai)
+      /* make the previous entry point to this */
+      prevai->ai_next = ai;
+
+    ai->ai_family = he->h_addrtype;
+
+    /* we return all names as STREAM, so when using this address for TFTP
+       the type must be ignored and conn->socktype be used instead! */
+    ai->ai_socktype = SOCK_STREAM;
+
+    ai->ai_addrlen = ss_size;
+    /* make the ai_addr point to the address immediately following this struct
+       and use that area to store the address */
+    ai->ai_addr = (struct sockaddr *) ((char*)ai + sizeof(Curl_addrinfo));
+
+    /* need to free this eventually */
+    ai->ai_canonname = strdup(he->h_name);
+
+    /* leave the rest of the struct filled with zero */
+
+    switch (ai->ai_family) {
+    case AF_INET:
+      addr = (struct sockaddr_in *)ai->ai_addr; /* storage area for this info */
+
+      memcpy((char *)&(addr->sin_addr), curr, sizeof(struct in_addr));
+      addr->sin_family = (unsigned short)(he->h_addrtype);
+      addr->sin_port = htons((unsigned short)port);
+      break;
+
+#ifdef CURLRES_IPV6
+    case AF_INET6:
+      addr6 = (struct sockaddr_in6 *)ai->ai_addr; /* storage area for this info */
+
+      memcpy((char *)&(addr6->sin6_addr), curr, sizeof(struct in6_addr));
+      addr6->sin6_family = (unsigned short)(he->h_addrtype);
+      addr6->sin6_port = htons((unsigned short)port);
+      break;
+#endif /* CURLRES_IPV6 */
+    }
+
+    prevai = ai;
+  }
+  return firstai;
+}
+
 #endif /* CURLRES_IPV4 || CURLRES_ARES */
-
-

lib/hostip.h

@@ -104,6 +104,10 @@
  */
 #ifdef CURLRES_IPV6
 typedef struct addrinfo Curl_addrinfo;
+#ifdef CURLRES_ARES
+Curl_addrinfo *Curl_ip2addr6(struct in6_addr *in,
+			     const char *hostname, int port);
+#endif
 #else
 /* OK, so some ipv4-only include tree probably have the addrinfo struct, but
    to work even on those that don't, we provide our own look-alike! */

lib/hostip4.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -307,91 +307,3 @@ Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
 #endif /* CURLRES_SYNCH */
 #endif /* CURLRES_IPV4 */
 
-/*
- * Curl_he2ai() translates from a hostent struct to a Curl_addrinfo struct.
- * The Curl_addrinfo is meant to work like the addrinfo struct does for IPv6
- * stacks, but for all hosts and environments.
- *
- *   Curl_addrinfo defined in "lib/hostip.h"
- *
- *     struct Curl_addrinfo {
- *       int                   ai_flags;
- *       int                   ai_family;
- *       int                   ai_socktype;
- *       int                   ai_protocol;
- *       socklen_t             ai_addrlen;   * Follow rfc3493 struct addrinfo *
- *       char                 *ai_canonname;
- *       struct sockaddr      *ai_addr;
- *       struct Curl_addrinfo *ai_next;
- *     };
- *
- *   hostent defined in <netdb.h>
- *
- *     struct hostent {
- *       char    *h_name;
- *       char    **h_aliases;
- *       int     h_addrtype;
- *       int     h_length;
- *       char    **h_addr_list;
- *     };
- *
- *   for backward compatibility:
- *
- *     #define h_addr  h_addr_list[0]
- */
-
-Curl_addrinfo *Curl_he2ai(const struct hostent *he, int port)
-{
-  Curl_addrinfo *ai;
-  Curl_addrinfo *prevai = NULL;
-  Curl_addrinfo *firstai = NULL;
-  struct sockaddr_in *addr;
-  int i;
-  struct in_addr *curr;
-
-  if(!he)
-    /* no input == no output! */
-    return NULL;
-
-  for(i=0; (curr = (struct in_addr *)he->h_addr_list[i]) != NULL; i++) {
-
-    ai = calloc(1, sizeof(Curl_addrinfo) + sizeof(struct sockaddr_in));
-
-    if(!ai)
-      break;
-
-    if(!firstai)
-      /* store the pointer we want to return from this function */
-      firstai = ai;
-
-    if(prevai)
-      /* make the previous entry point to this */
-      prevai->ai_next = ai;
-
-    ai->ai_family = AF_INET;              /* we only support this */
-
-    /* we return all names as STREAM, so when using this address for TFTP
-       the type must be ignored and conn->socktype be used instead! */
-    ai->ai_socktype = SOCK_STREAM;
-
-    ai->ai_addrlen = sizeof(struct sockaddr_in);
-    /* make the ai_addr point to the address immediately following this struct
-       and use that area to store the address */
-    ai->ai_addr = (struct sockaddr *) ((char*)ai + sizeof(Curl_addrinfo));
-
-    /* FIXME: need to free this eventually */
-    ai->ai_canonname = strdup(he->h_name);
-
-    /* leave the rest of the struct filled with zero */
-
-    addr = (struct sockaddr_in *)ai->ai_addr; /* storage area for this info */
-
-    memcpy((char *)&(addr->sin_addr), curr, sizeof(struct in_addr));
-    addr->sin_family = (unsigned short)(he->h_addrtype);
-    addr->sin_port = htons((unsigned short)port);
-
-    prevai = ai;
-  }
-  return firstai;
-}
-