[DCCP] Give precedence to the biggest ELAPSED_TIME

We can get this value in an TIMESTAMP_ECHO and/or in an ELAPSED_TIME option, if
receiving both give precendence to the biggest one.

In my tests they are very close if not equal at all times, so we may well think
about removing the code in CCID3 that inserts this option and leaving this to
the core, and perhaps even use just TIMESTAMP_ECHO including the elapsed time.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

net/dccp/options.c

@@ -72,6 +72,7 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 	struct dccp_options_received *opt_recv = &dp->dccps_options_received;
 	unsigned char opt, len;
 	unsigned char *value;
+	u32 elapsed_time;
 
 	memset(opt_recv, 0, sizeof(*opt_recv));
 
@@ -159,18 +160,18 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 				      (unsigned long long)
 				      DCCP_SKB_CB(skb)->dccpd_ack_seq);
 
-			if (len > 4) {
-				if (len == 6)
-					opt_recv->dccpor_elapsed_time =
-						 ntohs(*(u16 *)(value + 4));
-				else
-					opt_recv->dccpor_elapsed_time =
-						 ntohl(*(u32 *)(value + 4));
 
-				dccp_pr_debug("%sTIMESTAMP_ECHO ELAPSED_TIME=%d\n",
-				      debug_prefix,
-				      opt_recv->dccpor_elapsed_time);
-			}
+			if (len == 4)
+				break;
+
+			if (len == 6)
+				elapsed_time = ntohs(*(u16 *)(value + 4));
+			else
+				elapsed_time = ntohl(*(u32 *)(value + 4));
+
+			/* Give precedence to the biggest ELAPSED_TIME */
+			if (elapsed_time > opt_recv->dccpor_elapsed_time)
+				opt_recv->dccpor_elapsed_time = elapsed_time;
 			break;
 		case DCCPO_ELAPSED_TIME:
 			if (len != 2 && len != 4)
@@ -180,14 +181,15 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 				continue;
 
 			if (len == 2)
-				opt_recv->dccpor_elapsed_time =
-							ntohs(*(u16 *)value);
+				elapsed_time = ntohs(*(u16 *)value);
 			else
-				opt_recv->dccpor_elapsed_time =
-							ntohl(*(u32 *)value);
+				elapsed_time = ntohl(*(u32 *)value);
+
+			if (elapsed_time > opt_recv->dccpor_elapsed_time)
+				opt_recv->dccpor_elapsed_time = elapsed_time;
 
 			dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
-				      opt_recv->dccpor_elapsed_time);
+				      elapsed_time);
 			break;
 			/*
 			 * From draft-ietf-dccp-spec-11.txt: