[DCCP]: Fix the timestamp options

This changes timestamp, timestamp echo, and elapsed time to use units of 10
usecs as per DCCP spec. This has been tested to verify that times are correct.
Also fixed up length and used hton/ntoh more.

Still to add in later patches:
- actually use elapsed time to adjust RTT
(commented out as was prior to this patch)
- send options at times more closely following the spec
(content is now correct)

Signed-off-by: Ian McDonald <iam4@cs.waikato.ac.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/dccp.h

@@ -415,7 +415,7 @@ struct dccp_sock {
 	__u64				dccps_gsr;
 	__u64				dccps_gar;
 	unsigned long			dccps_service;
-	unsigned long			dccps_timestamp_time;
+	struct timeval			dccps_timestamp_time;
 	__u32				dccps_timestamp_echo;
 	__u32				dccps_avg_packet_size;
 	unsigned long			dccps_ndp_count;

net/dccp/ccids/ccid3.c

@@ -2,12 +2,12 @@
  *  net/dccp/ccids/ccid3.c
  *
  *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
+ *  Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
  *
  *  An implementation of the DCCP protocol
  *
  *  This code has been developed by the University of Waikato WAND
  *  research group. For further information please see http://www.wand.net.nz/
- *  or e-mail Ian McDonald - iam4@cs.waikato.ac.nz
  *
  *  This code also uses code from Lulea University, rereleased as GPL by its
  *  authors:
@@ -174,14 +174,6 @@ static inline void timeval_fix(struct timeval *tv)
 	}
 }
 
-/* returns the difference in usecs between timeval passed in and current time */
-static inline u32 now_delta(struct timeval tv) {
-	struct timeval now;
-
-	do_gettimeofday(&now);
-	return ((now.tv_sec-tv.tv_sec)*1000000+now.tv_usec-tv.tv_usec);
-}
-
 #define CALCX_ARRSIZE 500
 
 #define CALCX_SPLIT 50000
@@ -1110,7 +1102,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 	struct ccid3_options_received *opt_recv;
 	struct dccp_tx_hist_entry *packet;
 	unsigned long next_tmout; 
-	u16 t_elapsed;
+	u32 t_elapsed;
 	u32 pinv;
 	u32 x_recv;
 	u32 r_sample;

net/dccp/dccp.h

@@ -4,7 +4,8 @@
  *  net/dccp/dccp.h
  *
  *  An implementation of the DCCP protocol
- *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *  Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
  *
  *	This program is free software; you can redistribute it and/or modify it
  *	under the terms of the GNU General Public License version 2 as
@@ -404,6 +405,7 @@ extern struct socket *dccp_ctl_socket;
  * @dccpap_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
  *
  * @dccpap_buf_len - circular buffer length
+ * @dccpap_time		- the time in usecs
  * @dccpap_buf - circular buffer of acknowledgeable packets
  */
 struct dccp_ackpkts {
@@ -416,7 +418,7 @@ struct dccp_ackpkts {
 	unsigned int		dccpap_buf_vector_len;
 	unsigned int		dccpap_ack_vector_len;
 	unsigned int		dccpap_buf_len;
-	unsigned long           dccpap_time;
+	struct timeval		dccpap_time;
 	u8			dccpap_buf_nonce;
 	u8			dccpap_ack_nonce;
 	u8			dccpap_buf[0];
@@ -430,6 +432,19 @@ extern int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state);
 extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap,
 					 struct sock *sk, u64 ackno);
 
+/*
+ * Returns the difference in usecs between timeval
+ * passed in and current time
+ */
+static inline u32 now_delta(struct timeval tv)
+{
+	struct timeval now;
+
+	do_gettimeofday(&now);
+	return (now.tv_sec  - tv.tv_sec) * USEC_PER_SEC +
+	       (now.tv_usec - tv.tv_usec);
+}
+
 #ifdef CONFIG_IP_DCCP_DEBUG
 extern void dccp_ackvector_print(const u64 ackno,
 				 const unsigned char *vector, int len);

net/dccp/options.c

@@ -2,8 +2,9 @@
  *  net/dccp/options.c
  *
  *  An implementation of the DCCP protocol
- *  Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
- *  Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *  Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
+ *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
+ *  Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
  *
  *      This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
@@ -138,44 +139,53 @@ int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
 			opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
 
 			dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
-			dp->dccps_timestamp_time = jiffies;
+			do_gettimeofday(&dp->dccps_timestamp_time);
 
 			dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
 				      debug_prefix, opt_recv->dccpor_timestamp,
 				      (unsigned long long)
 				      DCCP_SKB_CB(skb)->dccpd_ack_seq);
 			break;
 		case DCCPO_TIMESTAMP_ECHO:
-			if (len < 4 || len > 8)
+			if (len != 4 && len != 6 && len != 8)
 				goto out_invalid_option;
 
 			opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
 
-			dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, "
-				      "diff=%u\n",
+			dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
 				      debug_prefix,
 				      opt_recv->dccpor_timestamp_echo,
 				      len + 2,
 				      (unsigned long long)
-				      DCCP_SKB_CB(skb)->dccpd_ack_seq,
-				      (tcp_time_stamp -
-				       opt_recv->dccpor_timestamp_echo));
-
-			opt_recv->dccpor_elapsed_time =
-					dccp_decode_value_var(value + 4,
-							     len - 4);
-			dccp_pr_debug("%sTIMESTAMP_ECHO ELAPSED_TIME=%d\n",
+				      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);
+			}
 			break;
 		case DCCPO_ELAPSED_TIME:
-			if (len > 4)
+			if (len != 2 && len != 4)
 				goto out_invalid_option;
 
 			if (pkt_type == DCCP_PKT_DATA)
 				continue;
-			opt_recv->dccpor_elapsed_time =
-					dccp_decode_value_var(value, len);
+
+			if (len == 2)
+				opt_recv->dccpor_elapsed_time =
+							ntohs(*(u16 *)value);
+			else
+				opt_recv->dccpor_elapsed_time =
+							ntohl(*(u32 *)value);
+
 			dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
 				      opt_recv->dccpor_elapsed_time);
 			break;
@@ -309,8 +319,7 @@ void dccp_insert_option_elapsed_time(struct sock *sk,
 	const int len = 2 + elapsed_time_len;
 	unsigned char *to;
 
-	/* If elapsed_time == 0... */
-	if (elapsed_time_len == 2)
+	if (elapsed_time_len == 0)
 		return;
 
 	if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
@@ -325,7 +334,13 @@ void dccp_insert_option_elapsed_time(struct sock *sk,
 	*to++ = DCCPO_ELAPSED_TIME;
 	*to++ = len;
 
-	dccp_encode_value_var(elapsed_time, to, elapsed_time_len);
+	if (elapsed_time_len == 2) {
+		const u16 var16 = htons((u16)elapsed_time);
+		memcpy(to, &var16, 2);
+	} else {
+		const u32 var32 = htonl(elapsed_time);
+		memcpy(to, &var32, 4);
+	}
 
 	dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
 		      debug_prefix, elapsed_time,
@@ -344,7 +359,7 @@ static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb)
 #endif
 	struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts;
 	int len = ap->dccpap_buf_vector_len + 2;
-	const u32 elapsed_time = jiffies_to_usecs(jiffies - ap->dccpap_time) / 10;
+	const u32 elapsed_time = now_delta(ap->dccpap_time) / 10;
 	unsigned char *to, *from;
 
 	if (elapsed_time != 0)
@@ -414,7 +429,15 @@ static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb)
 static inline void dccp_insert_option_timestamp(struct sock *sk,
 						struct sk_buff *skb)
 {
-	const u32 now = htonl(tcp_time_stamp);
+	struct timeval tv;
+	u32 now;
+
+	do_gettimeofday(&tv);
+	now = (tv.tv_sec * USEC_PER_SEC + tv.tv_usec) / 10;
+	/* yes this will overflow but that is the point as we want a
+	 * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
+
+	now = htonl(now);
 	dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
 }
 
@@ -427,8 +450,7 @@ static void dccp_insert_option_timestamp_echo(struct sock *sk,
 					"CLIENT TX opt: " : "server TX opt: ";
 #endif
 	u32 tstamp_echo;
-	const u32 elapsed_time = jiffies_to_usecs(jiffies -
-						  dp->dccps_timestamp_time) / 10;
+	const u32 elapsed_time = now_delta(dp->dccps_timestamp_time) / 10;
 	const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
 	const int len = 6 + elapsed_time_len;
 	unsigned char *to;
@@ -448,15 +470,23 @@ static void dccp_insert_option_timestamp_echo(struct sock *sk,
 	tstamp_echo = htonl(dp->dccps_timestamp_echo);
 	memcpy(to, &tstamp_echo, 4);
 	to += 4;
-	dccp_encode_value_var(elapsed_time, to, elapsed_time_len);
+
+	if (elapsed_time_len == 2) {
+		const u16 var16 = htons((u16)elapsed_time);
+		memcpy(to, &var16, 2);
+	} else if (elapsed_time_len == 4) {
+		const u32 var32 = htonl(elapsed_time);
+		memcpy(to, &var32, 4);
+	}
 
 	dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
 		      debug_prefix, dp->dccps_timestamp_echo,
 		      len,
 		      (unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
 
 	dp->dccps_timestamp_echo = 0;
-	dp->dccps_timestamp_time = 0;
+	dp->dccps_timestamp_time.tv_sec = 0;
+	dp->dccps_timestamp_time.tv_usec = 0;
 }
 
 void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
@@ -514,7 +544,8 @@ struct dccp_ackpkts *dccp_ackpkts_alloc(const unsigned int len,
 				ap->dccpap_ack_seqno = DCCP_MAX_SEQNO + 1;
 		ap->dccpap_buf_nonce = ap->dccpap_buf_nonce = 0;
 		ap->dccpap_ack_ptr   = 0;
-		ap->dccpap_time	     = 0;
+		ap->dccpap_time.tv_sec = 0;
+		ap->dccpap_time.tv_usec = 0;
 		ap->dccpap_buf_vector_len = ap->dccpap_ack_vector_len = 0;
 	}
 
@@ -665,7 +696,7 @@ int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state)
 	}
 
 	ap->dccpap_buf_ackno = ackno;
-	ap->dccpap_time = jiffies;
+	do_gettimeofday(&ap->dccpap_time);
 out:
 	dccp_pr_debug("");
 	dccp_ackpkts_print(ap);