[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, 119 insertions, 0 deletions

diff --git a/net/ipv4/udplite.c b/net/ipv4/udplite.c
new file mode 100644
index 000000000000..561de6d8c734
--- /dev/null
+++ b/net/ipv4/udplite.c
@@ -0,0 +1,119 @@
+/*
+ *  UDPLITE     An implementation of the UDP-Lite protocol (RFC 3828).
+ *
+ *  Version:    $Id: udplite.c,v 1.25 2006/10/19 07:22:36 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_statistics)    __read_mostly;
+
+struct hlist_head       udplite_hash[UDP_HTABLE_SIZE];
+static int              udplite_port_rover;
+
+__inline__ int udplite_get_port(struct sock *sk, unsigned short p,
+                        int (*c)(const struct sock *, const struct sock *))
+{
+        return  __udp_lib_get_port(sk, p, udplite_hash, &udplite_port_rover, c);
+}
+
+static __inline__ int udplite_v4_get_port(struct sock *sk, unsigned short snum)
+{
+        return udplite_get_port(sk, snum, ipv4_rcv_saddr_equal);
+}
+
+__inline__ int udplite_rcv(struct sk_buff *skb)
+{
+        return __udp4_lib_rcv(skb, udplite_hash, 1);
+}
+
+__inline__ void udplite_err(struct sk_buff *skb, u32 info)
+{
+        return __udp4_lib_err(skb, info, udplite_hash);
+}
+
+static  struct net_protocol udplite_protocol = {
+        .handler        = udplite_rcv,
+        .err_handler    = udplite_err,
+        .no_policy      = 1,
+};
+
+struct proto    udplite_prot = {
+        .name              = "UDP-Lite",
+        .owner             = THIS_MODULE,
+        .close             = udp_lib_close,
+        .connect           = ip4_datagram_connect,
+        .disconnect        = udp_disconnect,
+        .ioctl             = udp_ioctl,
+        .init              = udplite_sk_init,
+        .destroy           = udp_destroy_sock,
+        .setsockopt        = udp_setsockopt,
+        .getsockopt        = udp_getsockopt,
+        .sendmsg           = udp_sendmsg,
+        .recvmsg           = udp_recvmsg,
+        .sendpage          = udp_sendpage,
+        .backlog_rcv       = udp_queue_rcv_skb,
+        .hash              = udp_lib_hash,
+        .unhash            = udp_lib_unhash,
+        .get_port          = udplite_v4_get_port,
+        .obj_size          = sizeof(struct udp_sock),
+#ifdef CONFIG_COMPAT
+        .compat_setsockopt = compat_udp_setsockopt,
+        .compat_getsockopt = compat_udp_getsockopt,
+#endif
+};
+
+static struct inet_protosw udplite4_protosw = {
+        .type           =  SOCK_DGRAM,
+        .protocol       =  IPPROTO_UDPLITE,
+        .prot           =  &udplite_prot,
+        .ops            =  &inet_dgram_ops,
+        .capability     = -1,
+        .no_check       =  0,           /* must checksum (RFC 3828) */
+        .flags          =  INET_PROTOSW_PERMANENT,
+};
+
+#ifdef CONFIG_PROC_FS
+static struct file_operations udplite4_seq_fops;
+static struct udp_seq_afinfo udplite4_seq_afinfo = {
+        .owner          = THIS_MODULE,
+        .name           = "udplite",
+        .family         = AF_INET,
+        .hashtable      = udplite_hash,
+        .seq_show       = udp4_seq_show,
+        .seq_fops       = &udplite4_seq_fops,
+};
+#endif
+
+void __init udplite4_register(void)
+{
+        if (proto_register(&udplite_prot, 1))
+                goto out_register_err;
+
+        if (inet_add_protocol(&udplite_protocol, IPPROTO_UDPLITE) < 0)
+                goto out_unregister_proto;
+
+        inet_register_protosw(&udplite4_protosw);
+
+#ifdef CONFIG_PROC_FS
+        if (udp_proc_register(&udplite4_seq_afinfo)) /* udplite4_proc_init() */
+                printk(KERN_ERR "%s: Cannot register /proc!\n", __FUNCTION__);
+#endif
+        return;
+
+out_unregister_proto:
+        proto_unregister(&udplite_prot);
+out_register_err:
+        printk(KERN_CRIT "%s: Cannot add UDP-Lite protocol.\n", __FUNCTION__);
+}
+
+EXPORT_SYMBOL(udplite_hash);
+EXPORT_SYMBOL(udplite_prot);
+EXPORT_SYMBOL(udplite_get_port);