[DCCP]: Make feature negotiation more readable

This patch replaces cryptic feature negotiation messages of type

Oct 31 15:42:20 kernel: dccp_feat_change: feat change type=32 feat=1
Oct 31 15:42:21 kernel: dccp_feat_change: feat change type=34 feat=1
Oct 31 15:42:21 kernel: dccp_feat_change: feat change type=32 feat=5

into ones of type:

Nov  2 13:54:45 kernel: dccp_feat_change: ChangeL(CCID (1), 3)
Nov  2 13:54:45 kernel: dccp_feat_change: ChangeR(CCID (1), 3)
Nov  2 13:54:45 kernel: dccp_feat_change: ChangeL(Ack Ratio (5), 2)

Also,
	* completed the feature number list wrt RFC 4340 sec. 6.4
	* annotating which ones have been implemented so far
	* implemented rudimentary sanity checking in feat.c (FIXMEs)
	* some minor fixes

Commiter note: uninlined dccp_feat_name and dccp_feat_typename, for
               consistency with dccp_{state,packet}_name, that, BTW,
               should be compiled only if CONFIG_IP_DCCP_DEBUG is
               selected, leaving this to another cset tho. Also
               shortened dccp_feat_negotiation_debug to dccp_feat_debug.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 0502dfa..696319e 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -175,18 +175,21 @@
 	DCCPC_CCID3 = 3,
 };
 
-/* DCCP features */
-enum {
-	DCCPF_RESERVED = 0,
-	DCCPF_CCID = 1,
-	DCCPF_SEQUENCE_WINDOW = 3,
-	DCCPF_ACK_RATIO = 5,
-	DCCPF_SEND_ACK_VECTOR = 6,
-	DCCPF_SEND_NDP_COUNT = 7,
+/* DCCP features (RFC 4340 section 6.4) */
+ enum {
+ 	DCCPF_RESERVED = 0,
+ 	DCCPF_CCID = 1,
+	DCCPF_SHORT_SEQNOS = 2,		/* XXX: not yet implemented */
+ 	DCCPF_SEQUENCE_WINDOW = 3,
+	DCCPF_ECN_INCAPABLE = 4,	/* XXX: not yet implemented */
+ 	DCCPF_ACK_RATIO = 5,
+ 	DCCPF_SEND_ACK_VECTOR = 6,
+ 	DCCPF_SEND_NDP_COUNT = 7,
 	DCCPF_MIN_CSUM_COVER = 8,
-	/* 10-127 reserved */
-	DCCPF_MIN_CCID_SPECIFIC = 128,
-	DCCPF_MAX_CCID_SPECIFIC = 255,
+	DCCPF_DATA_CHECKSUM = 9,	/* XXX: not yet implemented */
+ 	/* 10-127 reserved */
+ 	DCCPF_MIN_CCID_SPECIFIC = 128,
+ 	DCCPF_MAX_CCID_SPECIFIC = 255,
 };
 
 /* this structure is argument to DCCP_SOCKOPT_CHANGE_X */