[NET]: Supporting UDP-Lite (RFC 3828) in Linux

This is a revision of the previously submitted patch, which alters
the way files are organized and compiled in the following manner:

	* UDP and UDP-Lite now use separate object files
	* source file dependencies resolved via header files
	  net/ipv{4,6}/udp_impl.h
	* order of inclusion files in udp.c/udplite.c adapted
	  accordingly

[NET/IPv4]: Support for the UDP-Lite protocol (RFC 3828)

This patch adds support for UDP-Lite to the IPv4 stack, provided as an
extension to the existing UDPv4 code:
        * generic routines are all located in net/ipv4/udp.c
        * UDP-Lite specific routines are in net/ipv4/udplite.c
        * MIB/statistics support in /proc/net/snmp and /proc/net/udplite
        * shared API with extensions for partial checksum coverage

[NET/IPv6]: Extension for UDP-Lite over IPv6

It extends the existing UDPv6 code base with support for UDP-Lite
in the same manner as per UDPv4. In particular,
        * UDPv6 generic and shared code is in net/ipv6/udp.c
        * UDP-Litev6 specific extensions are in net/ipv6/udplite.c
        * MIB/statistics support in /proc/net/snmp6 and /proc/net/udplite6
        * support for IPV6_ADDRFORM
        * aligned the coding style of protocol initialisation with af_inet6.c
        * made the error handling in udpv6_queue_rcv_skb consistent;
          to return `-1' on error on all error cases
        * consolidation of shared code

[NET]: UDP-Lite Documentation and basic XFRM/Netfilter support

The UDP-Lite patch further provides
        * API documentation for UDP-Lite
        * basic xfrm support
        * basic netfilter support for IPv4 and IPv6 (LOG target)

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 92bfccf..1eb1c7f 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -49,6 +49,7 @@
 #include <net/ip.h>
 #include <net/ipv6.h>
 #include <net/udp.h>
+#include <net/udplite.h>
 #include <net/tcp.h>
 #include <net/ipip.h>
 #include <net/protocol.h>
@@ -737,8 +738,13 @@
 	if (snmp6_mib_init((void **)udp_stats_in6, sizeof (struct udp_mib),
 			   __alignof__(struct udp_mib)) < 0)
 		goto err_udp_mib;
+	if (snmp6_mib_init((void **)udplite_stats_in6, sizeof (struct udp_mib),
+			   __alignof__(struct udp_mib)) < 0)
+		goto err_udplite_mib;
 	return 0;
 
+err_udplite_mib:
+	snmp6_mib_free((void **)udp_stats_in6);
 err_udp_mib:
 	snmp6_mib_free((void **)icmpv6_statistics);
 err_icmp_mib:
@@ -753,6 +759,7 @@
 	snmp6_mib_free((void **)ipv6_statistics);
 	snmp6_mib_free((void **)icmpv6_statistics);
 	snmp6_mib_free((void **)udp_stats_in6);
+	snmp6_mib_free((void **)udplite_stats_in6);
 }
 
 static int __init inet6_init(void)
@@ -780,10 +787,14 @@
 	if (err)
 		goto out_unregister_tcp_proto;
 
-	err = proto_register(&rawv6_prot, 1);
+	err = proto_register(&udplitev6_prot, 1);
 	if (err)
 		goto out_unregister_udp_proto;
 
+	err = proto_register(&rawv6_prot, 1);
+	if (err)
+		goto out_unregister_udplite_proto;
+
 
 	/* Register the socket-side information for inet6_create.  */
 	for(r = &inetsw6[0]; r < &inetsw6[SOCK_MAX]; ++r)
@@ -837,6 +848,8 @@
 		goto proc_tcp6_fail;
 	if (udp6_proc_init())
 		goto proc_udp6_fail;
+	if (udplite6_proc_init())
+		goto proc_udplite6_fail;
 	if (ipv6_misc_proc_init())
 		goto proc_misc6_fail;
 
@@ -862,6 +875,7 @@
 
 	/* Init v6 transport protocols. */
 	udpv6_init();
+	udplitev6_init();
 	tcpv6_init();
 
 	ipv6_packet_init();
@@ -879,6 +893,8 @@
 proc_anycast6_fail:
 	ipv6_misc_proc_exit();
 proc_misc6_fail:
+	udplite6_proc_exit();
+proc_udplite6_fail:
 	udp6_proc_exit();
 proc_udp6_fail:
 	tcp6_proc_exit();
@@ -902,6 +918,8 @@
 	sock_unregister(PF_INET6);
 out_unregister_raw_proto:
 	proto_unregister(&rawv6_prot);
+out_unregister_udplite_proto:
+	proto_unregister(&udplitev6_prot);
 out_unregister_udp_proto:
 	proto_unregister(&udpv6_prot);
 out_unregister_tcp_proto:
@@ -919,6 +937,7 @@
 	ac6_proc_exit();
  	ipv6_misc_proc_exit();
  	udp6_proc_exit();
+ 	udplite6_proc_exit();
  	tcp6_proc_exit();
  	raw6_proc_exit();
 #endif