[XFRM]: Fix statistics.

o Outbound sequence number overflow error status
is counted as XfrmOutStateSeqError.
o Additionaly, it changes inbound sequence number replay
error name from XfrmInSeqOutOfWindow to XfrmInStateSeqError
to apply name scheme above.
o Inbound IPv4 UDP encapsuling type mismatch error is wrongly
mapped to XfrmInStateInvalid then this patch fiex the error
to XfrmInStateMismatch.

Signed-off-by: Masahide NAKAMURA <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/networking/xfrm_proc.txt

···
 	e.g. SA key is wrong
 XfrmInStateModeError:
 	Transformation mode specific error
-XfrmInSeqOutOfWindow:
-	Sequence out of window
+XfrmInStateSeqError:
+	Sequence error
+	i.e. Sequence number is out of window
 XfrmInStateExpired:
 	State is expired
 XfrmInStateMismatch:
···
 	Transformation protocol specific error
 XfrmOutStateModeError:
 	Transformation mode specific error
+XfrmOutStateSeqError:
+	Sequence error
+	i.e. Sequence number overflow
 XfrmOutStateExpired:
 	State is expired
 XfrmOutPolBlock:

include/linux/snmp.h

···
 	LINUX_MIB_XFRMINNOSTATES,		/* XfrmInNoStates */
 	LINUX_MIB_XFRMINSTATEPROTOERROR,	/* XfrmInStateProtoError */
 	LINUX_MIB_XFRMINSTATEMODEERROR,		/* XfrmInStateModeError */
-	LINUX_MIB_XFRMINSEQOUTOFWINDOW,		/* XfrmInSeqOutOfWindow */
+	LINUX_MIB_XFRMINSTATESEQERROR,		/* XfrmInStateSeqError */
 	LINUX_MIB_XFRMINSTATEEXPIRED,		/* XfrmInStateExpired */
 	LINUX_MIB_XFRMINSTATEMISMATCH,		/* XfrmInStateMismatch */
 	LINUX_MIB_XFRMINSTATEINVALID,		/* XfrmInStateInvalid */
···
 	LINUX_MIB_XFRMOUTNOSTATES,		/* XfrmOutNoStates */
 	LINUX_MIB_XFRMOUTSTATEPROTOERROR,	/* XfrmOutStateProtoError */
 	LINUX_MIB_XFRMOUTSTATEMODEERROR,	/* XfrmOutStateModeError */
+	LINUX_MIB_XFRMOUTSTATESEQERROR,		/* XfrmOutStateSeqError */
 	LINUX_MIB_XFRMOUTSTATEEXPIRED,		/* XfrmOutStateExpired */
 	LINUX_MIB_XFRMOUTPOLBLOCK,		/* XfrmOutPolBlock */
 	LINUX_MIB_XFRMOUTPOLDEAD,		/* XfrmOutPolDead */

net/xfrm/xfrm_input.c

···
 		}
 
 		if ((x->encap ? x->encap->encap_type : 0) != encap_type) {
-			XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEINVALID);
+			XFRM_INC_STATS(LINUX_MIB_XFRMINSTATEMISMATCH);
 			goto drop_unlock;
 		}
 
 		if (x->props.replay_window && xfrm_replay_check(x, skb, seq)) {
-			XFRM_INC_STATS(LINUX_MIB_XFRMINSEQOUTOFWINDOW);
+			XFRM_INC_STATS(LINUX_MIB_XFRMINSTATESEQERROR);
 			goto drop_unlock;
 		}
 

net/xfrm/xfrm_output.c

···
 		if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 			XFRM_SKB_CB(skb)->seq = ++x->replay.oseq;
 			if (unlikely(x->replay.oseq == 0)) {
+				XFRM_INC_STATS(LINUX_MIB_XFRMOUTSTATESEQERROR);
 				x->replay.oseq--;
 				xfrm_audit_state_replay_overflow(x, skb);
 				err = -EOVERFLOW;

net/xfrm/xfrm_proc.c

···
 	SNMP_MIB_ITEM("XfrmInNoStates", LINUX_MIB_XFRMINNOSTATES),
 	SNMP_MIB_ITEM("XfrmInStateProtoError", LINUX_MIB_XFRMINSTATEPROTOERROR),
 	SNMP_MIB_ITEM("XfrmInStateModeError", LINUX_MIB_XFRMINSTATEMODEERROR),
-	SNMP_MIB_ITEM("XfrmInSeqOutOfWindow", LINUX_MIB_XFRMINSEQOUTOFWINDOW),
+	SNMP_MIB_ITEM("XfrmInStateSeqError", LINUX_MIB_XFRMINSTATESEQERROR),
 	SNMP_MIB_ITEM("XfrmInStateExpired", LINUX_MIB_XFRMINSTATEEXPIRED),
 	SNMP_MIB_ITEM("XfrmInStateMismatch", LINUX_MIB_XFRMINSTATEMISMATCH),
 	SNMP_MIB_ITEM("XfrmInStateInvalid", LINUX_MIB_XFRMINSTATEINVALID),
···
 	SNMP_MIB_ITEM("XfrmOutNoStates", LINUX_MIB_XFRMOUTNOSTATES),
 	SNMP_MIB_ITEM("XfrmOutStateProtoError", LINUX_MIB_XFRMOUTSTATEPROTOERROR),
 	SNMP_MIB_ITEM("XfrmOutStateModeError", LINUX_MIB_XFRMOUTSTATEMODEERROR),
+	SNMP_MIB_ITEM("XfrmOutStateSeqError", LINUX_MIB_XFRMOUTSTATESEQERROR),
 	SNMP_MIB_ITEM("XfrmOutStateExpired", LINUX_MIB_XFRMOUTSTATEEXPIRED),
 	SNMP_MIB_ITEM("XfrmOutPolBlock", LINUX_MIB_XFRMOUTPOLBLOCK),
 	SNMP_MIB_ITEM("XfrmOutPolDead", LINUX_MIB_XFRMOUTPOLDEAD),