Re: [patch] Add IPV6 'specials' flag to mod_rewrite - try 2

[Ryan Phillips]

Andr? Malo <[EMAIL PROTECTED]> said:
> * Ryan Phillips wrote:
> 
> > Ryan Phillips <[EMAIL PROTECTED]> said:
> > > Jeff Trawick <[EMAIL PROTECTED]> said:
> > > > On Mon, Jun 9, 2008 at 9:19 PM, Ryan Phillips 
> <[EMAIL PROTECTED]> wrote:
> > > > > Ryan Phillips <[EMAIL PROTECTED]> said:
> > > > >> So I needed to create some mod_rewrite rules only for IPv6 when
> > > > >> httpd is configured for both ipv4 and ipv6 modes.  This patch adds
> > > > >> 'RewriteCond IPV6 on' support to the ruleset.
> > > > >>
> > > > >> I initially tried to see if the incoming socket was APR_INET6, but
> > > > >> couldn't find the right structure within the request to query.
> > > > >
> > > > > Should r->connection->local_addr or remote_addr have the correct
> > > > > socket family?  If I try either of these over an IPv4 connection, I
> > > > > always get a socket family of IPv6.
> > > >
> > > > On most platforms, httpd will handle IPv4 connections on an IPv6
> > > > socket; the address family will be APR_INET6 and the socket address
> > > > will have a special format which indicates that the client is IPv4
> > > > (http://en.wikipedia.org/wiki/IPv4_mapped_address).
> > > >
> > > > Replace "Listen ##" with the combination "Listen 0.0.0.0:##" +
> > > > "Listen [::]:##" and you should be able to distinguish between client
> > > > connection type by checking the address family (not a real solution).
> > > >
> > > > The system macro IN6_IS_ADDR_V4MAPPED() can check if an IPv6 socket
> > > > address represents an IPv4 client connection.  Apparently APR doesn't
> > > > provide an equivalent.
> > >
> > > Jeff,
> > >
> > > Thanks for the detailed explanation.  I wasn't aware of this.
> >
> > Attached is a patch which uses IN6_IS_ADDR_V4MAPPED to see if the client
> > is from an IPv4 socket.
> 
> You should probably add conditionals for both macros (AF_INET6 and 
> IN6_IS_ADDR_V4MAPPED) and deal with non-existance properly. If INET6 is 
> missing, you can safely return "off", I think. If IN6_IS_ADDR_V4MAPPED is 
> missing - well, then "on" might be right.
> 
> Next point - which header files are the macros and structs in? Should we 
> include them explicitly? Or are they provided by APR already (and 
> officially)?
> 
> And finally, "return apr_strdup" should be replaced by "result = ". I know, 
> it's probably pasted from the HTTPS variable stuff, but that's not good 
> there too ;)
> 
> Ah, another last point - is your patch against trunk? It doesn't look like 
> it.

Thanks for the tips.  IN6_IS_ADDR_V4MAPPED is defined in netinet/in.h on
unices and APR defines it on windows.  I've modified the patch to check for
APR_HAVE_IPV6 support and check for APR_HAVE_NETINET_IN_H. Also, this patch will
apply to trunk/.

Thanks,
Ryan

Index: modules/mappers/mod_rewrite.c
===================================================================
--- modules/mappers/mod_rewrite.c	(revision 667098)
+++ modules/mappers/mod_rewrite.c	(working copy)
@@ -82,6 +82,9 @@
 #if APR_HAVE_CTYPE_H
 #include <ctype.h>
 #endif
+#if APR_HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
 
 #include "ap_config.h"
 #include "httpd.h"
@@ -1887,6 +1890,18 @@
                 rewritelog((r, 1, ctx->perdir, "RESULT='%s'", result));
                 return (char *)result;
             }
+            else if (!strcmp(var, "IPV6")) {
+                int flag = FALSE;
+#if APR_HAVE_IPV6
+                apr_sockaddr_t *addr = r->connection->remote_addr;
+                flag = (addr->family == AF_INET6 &&
+                        !IN6_IS_ADDR_V4MAPPED((struct in6_addr *)addr->ipaddr_ptr));
+                rewritelog((r, 1, ctx->perdir, "IPV6='%s'", flag ? "on" : "off"));
+#else
+                rewritelog((r, 1, ctx->perdir, "IPV6='off' (IPv6 is not enabled)"));
+#endif
+                result = (flag ? "on" : "off");
+            }
             break;
 
         case  5: