Commit 48e03eee authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
Browse files

[DCCP] ccid3: Consolidate timer resets 



This patch concerns updating the value of the nofeedback timer when no feedback
has been received so far.

Since in this case the value of R is still undefined according to [RFC 3448,
4.2], we can not perform step (3) of [RFC 3448, 4.3].  A clarification is
provided in [RFC 4342, sec. 5], which states that in these cases the nofeedback
timer (still) expires "after two seconds".

Many thanks to Ian McDonald for pointing this out and providing the
clarification.

The patch
  * implements [RFC 4342, sec. 5] with regard to the above case
  * consolidates handling timer restart by
	- adding an appropriate jump label and
	- initialising the timeout value

Acked-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@mandriva.com>
parent b798a9ed

net/dccp/ccids/ccid3.c

+9 −9
Original line number Diff line number Diff line
@@ -154,16 +154,14 @@ static void ccid3_hc_tx_update_x(struct sock *sk) 
static void ccid3_hc_tx_no_feedback_timer(unsigned long data)

{

	struct sock *sk = (struct sock *)data;

	unsigned long next_tmout = 0;

	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);

	unsigned long next_tmout = USEC_PER_SEC / 5;



	bh_lock_sock(sk);

	if (sock_owned_by_user(sk)) {

		/* Try again later. */

		/* XXX: set some sensible MIB */

		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,

			       jiffies + HZ / 5);

		goto out;

		goto restart_timer;

	}



	ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
@@ -183,9 +181,9 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data) 
			       dccp_role(sk), sk,

			       ccid3_tx_state_name(hctx->ccid3hctx_state),

			       hctx->ccid3hctx_x);

		next_tmout = max_t(u32, 2 * usecs_div(hctx->ccid3hctx_s,

						      hctx->ccid3hctx_x),

					TFRC_INITIAL_TIMEOUT);

		/* The value of R is still undefined and so we can not recompute

		 * the timout value. Keep initial value as per [RFC 4342, 5]. */

		next_tmout = TFRC_INITIAL_TIMEOUT;

		/*

		 * FIXME - not sure above calculation is correct. See section

		 * 5 of CCID3 11 should adjust tx_t_ipi and double that to
@@ -239,9 +237,11 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data) 
		goto out;

	}



	sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, 

		      jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));

	hctx->ccid3hctx_idle = 1;



restart_timer:

	sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,

		           jiffies + usecs_to_jiffies(next_tmout));

out:

	bh_unlock_sock(sk);

	sock_put(sk);

net/dccp/ccids/ccid3.h

+1 −1
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ 
#define TFRC_STD_PACKET_SIZE	  256

#define TFRC_MAX_PACKET_SIZE	65535



/* Two seconds as per CCID3 spec */

/* Two seconds as per RFC 3448 4.2 */

#define TFRC_INITIAL_TIMEOUT	   (2 * USEC_PER_SEC)



/* In usecs - half the scheduling granularity as per RFC3448 4.6 */

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