Re: AI_V4MAPPED/AI_ALL

[Thorsten Kukuk <kukuk@suse.de>]

[-- Attachment #1: Type: text/plain, Size: 1237 bytes --]

On Sat, Mar 29, Ulrich Drepper wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Thorsten Kukuk wrote:
> 
> > POSIX and rfc2553 mentions AI_V4MAPPED and AI_ALL as flags for
> > getaddrinfo(), but we removed them from the public header because
> > we don't want people to use them. What where the reasons for this?
> 
> The RFCs are changed far too frequently for my taste.  I'm not positive
> about adding anything not already in POSIX unless it's really proven to
> be stable and not changed in a couple of months.

Ok, AI_V4MAPPED and AI_ALL are specified in POSIX, rfc2553 and
rfc3493. So I doubt that it will be changed in the near future
again, I think something specified in POSIX should be stable 
enought to include in glibc.

I append a patch which adds both defines to resolv/netdb.h and
implements it in getaddrinfo(). (Looking at the ugly getaddrinfo
code, it seems we really need a new, clean implementation :( ).

  Thorsten

-- 
Thorsten Kukuk       http://www.suse.de/~kukuk/        kukuk@suse.de
SuSE Linux AG        Deutschherrnstr. 15-19        D-90429 Nuernberg
--------------------------------------------------------------------    
Key fingerprint = A368 676B 5E1B 3E46 CFCE  2D97 F8FD 4E23 56C6 FB4B

[-- Attachment #2: getaddrinfo.v4mapped.diff --]
[-- Type: text/plain, Size: 3089 bytes --]

2003-03-29  Thorsten Kukuk <kukuk@suse.de>

	* sysdeps/posix/getaddrinfo.c: Add support for AI_V4MAPPED/AI_ALL
	as described by POSIX and in rfc3493
	* resolv/netdb.h: Add AI_V4MAPPED/AI_ALL

--- resolv/netdb.h	2002-08-11 09:57:16.000000000 +0200
+++ resolv/netdb.h	2003-03-30 19:47:20.000000000 +0200
@@ -424,6 +424,8 @@
 # define AI_PASSIVE	0x0001	/* Socket address is intended for `bind'.  */
 # define AI_CANONNAME	0x0002	/* Request for canonical name.  */
 # define AI_NUMERICHOST	0x0004	/* Don't use name resolution.  */
+# define AI_V4MAPPED    0x0008  /* IPv4-mapped addresses are acceptable.  */
+# define AI_ALL         0x0010  /* Return both IPv4 and IPv6 addresses.  */
 
 /* Error values for `getaddrinfo' function.  */
 # define EAI_BADFLAGS	  -1	/* Invalid value for `ai_flags' field.  */
--- sysdeps/posix/getaddrinfo.c	2002-12-21 14:39:05.000000000 +0100
+++ sysdeps/posix/getaddrinfo.c	2003-03-30 19:51:35.000000000 +0200
@@ -52,6 +52,9 @@
 #include <net/if.h>
 #include <nsswitch.h>
 
+/* Get implementation for some internal functions. */
+#include <resolv/mapv4v6addr.h>
+
 #define GAIH_OKIFUNSPEC 0x0100
 #define GAIH_EAI        ~(GAIH_OKIFUNSPEC)
 
@@ -368,6 +371,7 @@
   struct gaih_servtuple *st = (struct gaih_servtuple *) &nullserv;
   struct gaih_addrtuple *at = NULL;
   int rc;
+  int v4mapped = (req->ai_family == AF_INET6) && (req->ai_flags & AI_V4MAPPED);
 
   if (req->ai_protocol || req->ai_socktype)
     {
@@ -488,7 +492,7 @@
 
       if (inet_pton (AF_INET, name, at->addr) > 0)
 	{
-	  if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET)
+	  if (req->ai_family == AF_UNSPEC || req->ai_family == AF_INET || v4mapped)
 	    at->family = AF_INET;
 	  else
 	    return -EAI_ADDRFAMILY;
@@ -609,7 +613,10 @@
 	      gethosts (AF_INET6, struct in6_addr);
 	      no_inet6_data = no_data;
 	    }
-	  else if (req->ai_family == AF_INET)
+
+	  if (req->ai_family == AF_INET ||
+	      (v4mapped && (no_inet6_data != 0 || h == NULL
+			    || (req->ai_flags & AI_ALL))))
 	    gethosts (AF_INET, struct in_addr);
 
 	  if (no_data != 0 && no_inet6_data != 0)
@@ -745,7 +751,7 @@
 	else
 	  namelen = 0;
 
-	if (at2->family == AF_INET6)
+	if (at2->family == AF_INET6 || v4mapped)
 	  {
 	    family = AF_INET6;
 	    socklen = sizeof (struct sockaddr_in6);
@@ -779,8 +785,13 @@
 		  (struct sockaddr_in6 *) (*pai)->ai_addr;
 
 		sin6p->sin6_flowinfo = 0;
-		memcpy (&sin6p->sin6_addr,
-			at2->addr, sizeof (struct in6_addr));
+		if (at2->family == AF_INET6)
+		  memcpy (&sin6p->sin6_addr,
+			  at2->addr, sizeof (struct in6_addr));
+		else
+		  map_v4v6_address ((char *)&at2->addr,
+				    (char *)&sin6p->sin6_addr);
+
 		sin6p->sin6_port = st2->port;
 		sin6p->sin6_scope_id = at2->scopeid;
 	      }
@@ -844,7 +854,8 @@
   if (hints == NULL)
     hints = &default_hints;
 
-  if (hints->ai_flags & ~(AI_PASSIVE|AI_CANONNAME|AI_NUMERICHOST))
+  if (hints->ai_flags & ~(AI_PASSIVE|AI_CANONNAME|AI_NUMERICHOST|
+                          AI_V4MAPPED|AI_ALL))
     return EAI_BADFLAGS;
 
   if ((hints->ai_flags & AI_CANONNAME) && name == NULL)