Add support for clients that sent ipv4 addresses to a dual-stacked host
Christoph Bartoschek
bartoschek at or.uni-bonn.de
Sat Nov 28 03:15:33 PST 2009
Hi,
I have problems to connect from ipv4-only thin clients to our xdm server.
There is a bug in the novell-bugzilla:
http://bugzilla.novell.com/show_bug.cgi?id=546632
The reason is that ipv4 addresses are discarded if they are received over a
ipv6 socket. The attached patch fixes this.
I did not test it yet. I will do it on monday when I have access to the thin
clients. However I wanted to get feedback whether such a patch is wanted and
what you think about the approach before I invest more time:
Christoph Bartoschek
---
xdmcp.c | 21 ++++++++++++++++++---
1 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/xdmcp.c b/xdmcp.c
index 7c91d1e..447b744 100644
--- a/xdmcp.c
+++ b/xdmcp.c
@@ -791,8 +791,8 @@ forward_respond (
{
struct sockaddr_in6 in6_addr;
- if (clientAddress.length != 16 ||
- clientPort.length != 2)
+ if ((clientAddress.length != 16 && clientAddress.length != 4) ||
+ (clientPort.length != 2))
{
goto badAddress;
}
@@ -801,7 +801,22 @@ forward_respond (
in6_addr.sin6_len = sizeof(in6_addr);
# endif
in6_addr.sin6_family = AF_INET6;
- memmove(&in6_addr.sin6_addr,clientAddress.data,clientAddress.length);
+ if (clientAddress.length == 16) {
+ memmove(in6_addr.sin6_addr.s6_addr, clientAddress.data, 16);
+ } else {
+ /* If the client wants to forward the xdm server to an
+ ipv4 hosts it sends an ipv4 address in the forward
+ packet. On dual-stack hosts the packet arrives as a
+ ipv6 packet. To respond to the ipv4 host one has
+ to create an ipv4-mapped address.
+
+ One example where this is necessary is an ipv4-only
+ thin client that connects to a dual-stacked xdm.
+ */
+ in6_addr.sin6_addr.s6_addr[10] = 0xff;
+ in6_addr.sin6_addr.s6_addr[11] = 0xff;
+ memmove(in6_addr.sin6_addr.s6_addr + 12, clientAddress.data, 4);
+ }
memmove((char *) &in6_addr.sin6_port, clientPort.data, 2);
client = (struct sockaddr *) &in6_addr;
clientlen = sizeof (in6_addr);
--
1.6.5.3
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