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

[Ryan Phillips]

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.

Thanks,
Ryan

--- mod_rewrite.c.old	2008-06-09 16:50:04.000000000 -0500
+++ mod_rewrite.c	2008-06-11 12:09:50.000000000 -0500
@@ -1765,6 +1765,13 @@
                 rewritelog((r, 1, ctx->perdir, "RESULT='%s'", result));
                 return (char *)result;
             }
+            else if (!strcmp(var, "IPV6")) {
+                apr_sockaddr_t *addr = r->connection->remote_addr;
+                int 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"));
+                return apr_pstrdup(r->pool, flag ? "on" : "off");
+            }
             break;
 
         case  5: