[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>

3 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/in.h b/include/linux/in.h
index 2619859f6e1b..1912e7c0bc26 100644
--- a/include/linux/in.h
+++ b/include/linux/in.h
@@ -45,6 +45,7 @@ enum {
 
   IPPROTO_COMP   = 108,                /* Compression Header protocol */
   IPPROTO_SCTP   = 132,         /* Stream Control Transport Protocol    */
+  IPPROTO_UDPLITE = 136,        /* UDP-Lite (RFC 3828)                  */
 
   IPPROTO_RAW    = 255,         /* Raw IP packets                       */
   IPPROTO_MAX
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 361409094649..592b66679823 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -264,6 +264,7 @@ struct ucred {
 #define SOL_IPV6        41
 #define SOL_ICMPV6      58
 #define SOL_SCTP        132
+#define SOL_UDPLITE     136     /* UDP-Lite (RFC 3828) */
 #define SOL_RAW         255
 #define SOL_IPX         256
 #define SOL_AX25        257
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 014b41d1e308..564f3b050105 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -38,6 +38,7 @@ struct udphdr {
 #include <linux/types.h>
 
 #include <net/inet_sock.h>
+#define UDP_HTABLE_SIZE         128
 
 struct udp_sock {
         /* inet_sock has to be the first member */
@@ -50,12 +51,23 @@ struct udp_sock {
          * when the socket is uncorked.
          */
         __u16            len;           /* total length of pending frames */
+        /*
+         * Fields specific to UDP-Lite.
+         */
+        __u16            pcslen;
+        __u16            pcrlen;
+/* indicator bits used by pcflag: */
+#define UDPLITE_BIT      0x1            /* set by udplite proto init function */
+#define UDPLITE_SEND_CC  0x2            /* set via udplite setsockopt         */
+#define UDPLITE_RECV_CC  0x4            /* set via udplite setsocktopt        */
+        __u8             pcflag;        /* marks socket as UDP-Lite if > 0    */
 };
 
 static inline struct udp_sock *udp_sk(const struct sock *sk)
 {
         return (struct udp_sock *)sk;
 }
+#define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)
 
 #endif