[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>

1 files changed, 105 insertions, 0 deletions

diff --git a/net/ipv6/udplite.c b/net/ipv6/udplite.c
new file mode 100644
index 000000000000..e0ec5e63004a
--- /dev/null
+++ b/net/ipv6/udplite.c
@@ -0,0 +1,105 @@
+/*
+ *  UDPLITEv6   An implementation of the UDP-Lite protocol over IPv6.
+ *              See also net/ipv4/udplite.c
+ *
+ *  Version:    $Id: udplite.c,v 1.9 2006/10/19 08:28:10 gerrit Exp $
+ *
+ *  Authors:    Gerrit Renker       <gerrit@erg.abdn.ac.uk>
+ *
+ *  Changes:
+ *  Fixes:
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ */
+#include "udp_impl.h"
+
+DEFINE_SNMP_STAT(struct udp_mib, udplite_stats_in6) __read_mostly;
+
+static __inline__ int udplitev6_rcv(struct sk_buff **pskb)
+{
+        return __udp6_lib_rcv(pskb, udplite_hash, 1);
+}
+
+static __inline__ void udplitev6_err(struct sk_buff *skb,
+                                     struct inet6_skb_parm *opt,
+                                     int type, int code, int offset, __u32 info)
+{
+        return __udp6_lib_err(skb, opt, type, code, offset, info, udplite_hash);
+}
+
+static struct inet6_protocol udplitev6_protocol = {
+        .handler        =       udplitev6_rcv,
+        .err_handler    =       udplitev6_err,
+        .flags          =       INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
+};
+
+static __inline__ int udplite_v6_get_port(struct sock *sk, unsigned short snum)
+{
+        return udplite_get_port(sk, snum, ipv6_rcv_saddr_equal);
+}
+
+struct proto udplitev6_prot = {
+        .name              = "UDPLITEv6",
+        .owner             = THIS_MODULE,
+        .close             = udp_lib_close,
+        .connect           = ip6_datagram_connect,
+        .disconnect        = udp_disconnect,
+        .ioctl             = udp_ioctl,
+        .init              = udplite_sk_init,
+        .destroy           = udpv6_destroy_sock,
+        .setsockopt        = udpv6_setsockopt,
+        .getsockopt        = udpv6_getsockopt,
+        .sendmsg           = udpv6_sendmsg,
+        .recvmsg           = udpv6_recvmsg,
+        .backlog_rcv       = udpv6_queue_rcv_skb,
+        .hash              = udp_lib_hash,
+        .unhash            = udp_lib_unhash,
+        .get_port          = udplite_v6_get_port,
+        .obj_size          = sizeof(struct udp6_sock),
+#ifdef CONFIG_COMPAT
+        .compat_setsockopt = compat_udpv6_setsockopt,
+        .compat_getsockopt = compat_udpv6_getsockopt,
+#endif
+};
+
+static struct inet_protosw udplite6_protosw = {
+        .type           = SOCK_DGRAM,
+        .protocol       = IPPROTO_UDPLITE,
+        .prot           = &udplitev6_prot,
+        .ops            = &inet6_dgram_ops,
+        .capability     = -1,
+        .no_check       = 0,
+        .flags          = INET_PROTOSW_PERMANENT,
+};
+
+void __init udplitev6_init(void)
+{
+        if (inet6_add_protocol(&udplitev6_protocol, IPPROTO_UDPLITE) < 0)
+                printk(KERN_ERR "%s: Could not register.\n", __FUNCTION__);
+
+        inet6_register_protosw(&udplite6_protosw);
+}
+
+#ifdef CONFIG_PROC_FS
+static struct file_operations udplite6_seq_fops;
+static struct udp_seq_afinfo udplite6_seq_afinfo = {
+        .owner          = THIS_MODULE,
+        .name           = "udplite6",
+        .family         = AF_INET6,
+        .hashtable      = udplite_hash,
+        .seq_show       = udp6_seq_show,
+        .seq_fops       = &udplite6_seq_fops,
+};
+
+int __init udplite6_proc_init(void)
+{
+        return udp_proc_register(&udplite6_seq_afinfo);
+}
+
+void udplite6_proc_exit(void)
+{
+        udp_proc_unregister(&udplite6_seq_afinfo);
+}
+#endif