Commit 2f3e3bba authored by Gerrit Renker's avatar Gerrit Renker
Browse files

dccp ccid-3: Remove duplicate RX states 



The only state information that the CCID-3 receiver keeps is whether initial 
feedback has been sent or not. Further, this overlaps with use of feedback:

 * state == TFRC_RSTATE_NO_DATA as long as no feedback has been sent;
 * state == TFRC_RSTATE_DATA    as soon as the first feedback has been sent.

This patch reduces the duplication, by memorising the type of the last feedback.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
parent 34a081be

net/dccp/ccids/ccid3.c

+5 −42
Original line number Diff line number Diff line
@@ -528,40 +528,6 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, 
/*

 *	Receiver Half-Connection Routines

 */



/* CCID3 feedback types */

enum ccid3_fback_type {

	CCID3_FBACK_NONE = 0,

	CCID3_FBACK_INITIAL,

	CCID3_FBACK_PERIODIC,

	CCID3_FBACK_PARAM_CHANGE

};



#ifdef CONFIG_IP_DCCP_CCID3_DEBUG

static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)

{

	static char *ccid3_rx_state_names[] = {

	[TFRC_RSTATE_NO_DATA] = "NO_DATA",

	[TFRC_RSTATE_DATA]    = "DATA",

	};



	return ccid3_rx_state_names[state];

}

#endif



static void ccid3_hc_rx_set_state(struct sock *sk,

				  enum ccid3_hc_rx_states state)

{

	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);

	enum ccid3_hc_rx_states oldstate = hcrx->state;



	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",

		       dccp_role(sk), sk, ccid3_rx_state_name(oldstate),

		       ccid3_rx_state_name(state));

	WARN_ON(state == oldstate);

	hcrx->state = state;

}



static void ccid3_hc_rx_send_feedback(struct sock *sk,

				      const struct sk_buff *skb,

				      enum ccid3_fback_type fbtype)
@@ -577,7 +543,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk, 
		hcrx->p_inverse = ~0U;   /* see RFC 4342, 8.5 */

		break;

	case CCID3_FBACK_PARAM_CHANGE:

		if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) {

		if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) {

			/*

			 * rfc3448bis-06, 6.3.1: First packet(s) lost or marked

			 * FIXME: in rfc3448bis the receiver returns X_recv=0
@@ -626,6 +592,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk, 
	hcrx->tstamp_last_feedback = now;

	hcrx->last_counter	   = dccp_hdr(skb)->dccph_ccval;

	hcrx->hist.bytes_recvd	   = 0;

	hcrx->feedback		   = fbtype;



	dp->dccps_hc_rx_insert_options = 1;

	dccp_send_ack(sk);
@@ -675,7 +642,7 @@ static u32 ccid3_first_li(struct sock *sk) 
	 * to give the equivalent of X_target = s/(2*R). Thus fval = 2 and so p

	 * is about 20.64%. This yields an interval length of 4.84 (rounded up).

	 */

	if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA))

	if (unlikely(hcrx->feedback == CCID3_FBACK_NONE))

		return 5;



	if (hcrx->rtt == 0) {
@@ -719,11 +686,9 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) 
		goto done_receiving;

	}



	if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) {

		if (is_data_packet) {

	if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) {

		if (is_data_packet)

			do_feedback = CCID3_FBACK_INITIAL;

			ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);

		}

		goto update_records;

	}
@@ -764,7 +729,6 @@ static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) 
{

	struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);



	hcrx->state = TFRC_RSTATE_NO_DATA;

	tfrc_lh_init(&hcrx->li_hist);

	return tfrc_rx_hist_init(&hcrx->hist, sk);

}
@@ -779,7 +743,6 @@ static void ccid3_hc_rx_exit(struct sock *sk) 


static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)

{

	info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->state;

	info->tcpi_options  |= TCPI_OPT_TIMESTAMPS;

	info->tcpi_rcv_rtt  = ccid3_hc_rx_sk(sk)->rtt;

}

net/dccp/ccids/ccid3.h

+8 −6
Original line number Diff line number Diff line
@@ -114,16 +114,18 @@ static inline struct ccid3_hc_tx_sock *ccid3_hc_tx_sk(const struct sock *sk) 
    return hctx;

}



/* TFRC receiver states */

enum ccid3_hc_rx_states {

	TFRC_RSTATE_NO_DATA = 1,

	TFRC_RSTATE_DATA,



enum ccid3_fback_type {

	CCID3_FBACK_NONE = 0,

	CCID3_FBACK_INITIAL,

	CCID3_FBACK_PERIODIC,

	CCID3_FBACK_PARAM_CHANGE

};



/** struct ccid3_hc_rx_sock - CCID3 receiver half-connection socket

 *

 *  @last_counter  -  Tracks window counter (RFC 4342, 8.1)

 *  @state  -  Receiver state, one of %ccid3_hc_rx_states

 *  @feedback  -  The type of the feedback last sent

 *  @x_recv  -  Receiver estimate of send rate (RFC 3448, sec. 4.3)

 *  @rtt  -  Receiver estimate of RTT

 *  @tstamp_last_feedback  -  Time at which last feedback was sent
@@ -133,7 +135,7 @@ enum ccid3_hc_rx_states { 
 */

struct ccid3_hc_rx_sock {

	u8				last_counter:4;

	enum ccid3_hc_rx_states		state:8;

	enum ccid3_fback_type		feedback:4;

	u32				x_recv;

	u32				rtt;

	ktime_t				tstamp_last_feedback;

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