1 files changed, 90 insertions, 166 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index 95f7529..3060a60 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -54,7 +54,6 @@ static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
 	[TFRC_SSTATE_NO_SENT]  = "NO_SENT",
 	[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
 	[TFRC_SSTATE_FBACK]    = "FBACK",
-	[TFRC_SSTATE_TERM]     = "TERM",
 	};
 
 	return ccid3_state_names[state];
@@ -91,19 +90,16 @@ static inline u64 rfc3390_initial_rate(struct sock *sk)
 	return scaled_div(w_init << 6, hc->tx_rtt);
 }
 
-/*
- * Recalculate t_ipi and delta (should be called whenever X changes)
+/**
+ * ccid3_update_send_interval  -  Calculate new t_ipi = s / X_inst
+ * This respects the granularity of X_inst (64 * bytes/second).
  */
 static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
 {
-	/* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
 	hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
 
-	/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
-	hc->tx_delta = min_t(u32, hc->tx_t_ipi / 2, TFRC_OPSYS_HALF_TIME_GRAN);
-
-	ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n", hc->tx_t_ipi,
-		       hc->tx_delta, hc->tx_s, (unsigned)(hc->tx_x >> 6));
+	ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
+		       hc->tx_s, (unsigned)(hc->tx_x >> 6));
 }
 
 static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
@@ -211,16 +207,19 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
 	ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
 		       ccid3_tx_state_name(hc->tx_state));
 
+	/* Ignore and do not restart after leaving the established state */
+	if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
+		goto out;
+
+	/* Reset feedback state to "no feedback received" */
 	if (hc->tx_state == TFRC_SSTATE_FBACK)
 		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
-	else if (hc->tx_state != TFRC_SSTATE_NO_FBACK)
-		goto out;
 
 	/*
 	 * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
+	 * RTO is 0 if and only if no feedback has been received yet.
 	 */
-	if (hc->tx_t_rto == 0 ||	/* no feedback received yet */
-	    hc->tx_p == 0) {
+	if (hc->tx_t_rto == 0 || hc->tx_p == 0) {
 
 		/* halve send rate directly */
 		hc->tx_x = max(hc->tx_x / 2,
@@ -256,7 +255,7 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
 	 * Set new timeout for the nofeedback timer.
 	 * See comments in packet_recv() regarding the value of t_RTO.
 	 */
-	if (unlikely(hc->tx_t_rto == 0))	/* no feedback yet */
+	if (unlikely(hc->tx_t_rto == 0))	/* no feedback received yet */
 		t_nfb = TFRC_INITIAL_TIMEOUT;
 	else
 		t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
@@ -290,8 +289,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 	if (unlikely(skb->len == 0))
 		return -EBADMSG;
 
-	switch (hc->tx_state) {
-	case TFRC_SSTATE_NO_SENT:
+	if (hc->tx_state == TFRC_SSTATE_NO_SENT) {
 		sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies +
 			       usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
 		hc->tx_last_win_count	= 0;
@@ -326,27 +324,22 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 		ccid3_update_send_interval(hc);
 
 		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
-		break;
-	case TFRC_SSTATE_NO_FBACK:
-	case TFRC_SSTATE_FBACK:
+
+	} else {
 		delay = ktime_us_delta(hc->tx_t_nom, now);
 		ccid3_pr_debug("delay=%ld\n", (long)delay);
 		/*
-		 *	Scheduling of packet transmissions [RFC 3448, 4.6]
+		 *	Scheduling of packet transmissions (RFC 5348, 8.3)
 		 *
 		 * if (t_now > t_nom - delta)
 		 *       // send the packet now
 		 * else
 		 *       // send the packet in (t_nom - t_now) milliseconds.
 		 */
-		if (delay - (s64)hc->tx_delta >= 1000)
-			return (u32)delay / 1000L;
+		if (delay >= TFRC_T_DELTA)
+			return (u32)delay / USEC_PER_MSEC;
 
 		ccid3_hc_tx_update_win_count(hc, now);
-		break;
-	case TFRC_SSTATE_TERM:
-		DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
-		return -EINVAL;
 	}
 
 	/* prepare to send now (add options etc.) */
@@ -358,8 +351,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 	return 0;
 }
 
-static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
-				    unsigned int len)
+static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
 {
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
 
@@ -372,48 +364,34 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 {
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
-	struct ccid3_options_received *opt_recv;
+	struct tfrc_tx_hist_entry *acked;
 	ktime_t now;
 	unsigned long t_nfb;
-	u32 pinv, r_sample;
+	u32 r_sample;
 
 	/* we are only interested in ACKs */
 	if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
 	      DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
 		return;
-	/* ... and only in the established state */
-	if (hc->tx_state != TFRC_SSTATE_FBACK &&
-	    hc->tx_state != TFRC_SSTATE_NO_FBACK)
-		return;
-
-	opt_recv = &hc->tx_options_received;
-	now = ktime_get_real();
-
-	/* Estimate RTT from history if ACK number is valid */
-	r_sample = tfrc_tx_hist_rtt(hc->tx_hist,
-				    DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
-	if (r_sample == 0) {
-		DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
-			  dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
-			  (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
-		return;
-	}
-
-	/* Update receive rate in units of 64 * bytes/second */
-	hc->tx_x_recv = opt_recv->ccid3or_receive_rate;
-	hc->tx_x_recv <<= 6;
-
-	/* Update loss event rate (which is scaled by 1e6) */
-	pinv = opt_recv->ccid3or_loss_event_rate;
-	if (pinv == ~0U || pinv == 0)	       /* see RFC 4342, 8.5   */
-		hc->tx_p = 0;
-	else				       /* can not exceed 100% */
-		hc->tx_p = scaled_div(1, pinv);
 	/*
-	 * Validate new RTT sample and update moving average
+	 * Locate the acknowledged packet in the TX history.
+	 *
+	 * Returning "entry not found" here can for instance happen when
+	 *  - the host has not sent out anything (e.g. a passive server),
+	 *  - the Ack is outdated (packet with higher Ack number was received),
+	 *  - it is a bogus Ack (for a packet not sent on this connection).
 	 */
-	r_sample = dccp_sample_rtt(sk, r_sample);
+	acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
+	if (acked == NULL)
+		return;
+	/* For the sake of RTT sampling, ignore/remove all older entries */
+	tfrc_tx_hist_purge(&acked->next);
+
+	/* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
+	now	  = ktime_get_real();
+	r_sample  = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
 	hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
+
 	/*
 	 * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
 	 */
@@ -461,13 +439,12 @@ done_computing_x:
 	sk->sk_write_space(sk);
 
 	/*
-	 * Update timeout interval for the nofeedback timer.
-	 * We use a configuration option to increase the lower bound.
-	 * This can help avoid triggering the nofeedback timer too
-	 * often ('spinning') on LANs with small RTTs.
+	 * Update timeout interval for the nofeedback timer. In order to control
+	 * rate halving on networks with very low RTTs (<= 1 ms), use per-route
+	 * tunable RTAX_RTO_MIN value as the lower bound.
 	 */
-	hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt, (CONFIG_IP_DCCP_CCID3_RTO *
-						       (USEC_PER_SEC / 1000)));
+	hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
+				  USEC_PER_SEC/HZ * tcp_rto_min(sk));
 	/*
 	 * Schedule no feedback timer to expire in
 	 * max(t_RTO, 2 * s/X)  =  max(t_RTO, 2 * t_ipi)
@@ -482,66 +459,41 @@ done_computing_x:
 			   jiffies + usecs_to_jiffies(t_nfb));
 }
 
-static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
-				     unsigned char len, u16 idx,
-				     unsigned char *value)
+static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+				     u8 option, u8 *optval, u8 optlen)
 {
-	int rc = 0;
-	const struct dccp_sock *dp = dccp_sk(sk);
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
-	struct ccid3_options_received *opt_recv;
 	__be32 opt_val;
 
-	opt_recv = &hc->tx_options_received;
-
-	if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
-		opt_recv->ccid3or_seqno		     = dp->dccps_gsr;
-		opt_recv->ccid3or_loss_event_rate    = ~0;
-		opt_recv->ccid3or_loss_intervals_idx = 0;
-		opt_recv->ccid3or_loss_intervals_len = 0;
-		opt_recv->ccid3or_receive_rate	     = 0;
-	}
-
 	switch (option) {
+	case TFRC_OPT_RECEIVE_RATE:
 	case TFRC_OPT_LOSS_EVENT_RATE:
-		if (unlikely(len != 4)) {
-			DCCP_WARN("%s(%p), invalid len %d "
-				  "for TFRC_OPT_LOSS_EVENT_RATE\n",
-				  dccp_role(sk), sk, len);
-			rc = -EINVAL;
-		} else {
-			opt_val = get_unaligned((__be32 *)value);
-			opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
-			ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
-				       dccp_role(sk), sk,
-				       opt_recv->ccid3or_loss_event_rate);
+		/* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */
+		if (packet_type == DCCP_PKT_DATA)
+			break;
+		if (unlikely(optlen != 4)) {
+			DCCP_WARN("%s(%p), invalid len %d for %u\n",
+				  dccp_role(sk), sk, optlen, option);
+			return -EINVAL;
 		}
-		break;
-	case TFRC_OPT_LOSS_INTERVALS:
-		opt_recv->ccid3or_loss_intervals_idx = idx;
-		opt_recv->ccid3or_loss_intervals_len = len;
-		ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
-			       dccp_role(sk), sk,
-			       opt_recv->ccid3or_loss_intervals_idx,
-			       opt_recv->ccid3or_loss_intervals_len);
-		break;
-	case TFRC_OPT_RECEIVE_RATE:
-		if (unlikely(len != 4)) {
-			DCCP_WARN("%s(%p), invalid len %d "
-				  "for TFRC_OPT_RECEIVE_RATE\n",
-				  dccp_role(sk), sk, len);
-			rc = -EINVAL;
-		} else {
-			opt_val = get_unaligned((__be32 *)value);
-			opt_recv->ccid3or_receive_rate = ntohl(opt_val);
+		opt_val = ntohl(get_unaligned((__be32 *)optval));
+
+		if (option == TFRC_OPT_RECEIVE_RATE) {
+			/* Receive Rate is kept in units of 64 bytes/second */
+			hc->tx_x_recv = opt_val;
+			hc->tx_x_recv <<= 6;
+
 			ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
-				       dccp_role(sk), sk,
-				       opt_recv->ccid3or_receive_rate);
+				       dccp_role(sk), sk, opt_val);
+		} else {
+			/* Update the fixpoint Loss Event Rate fraction */
+			hc->tx_p = tfrc_invert_loss_event_rate(opt_val);
+
+			ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
+				       dccp_role(sk), sk, opt_val);
 		}
-		break;
 	}
-
-	return rc;
+	return 0;
 }
 
 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
@@ -559,42 +511,36 @@ static void ccid3_hc_tx_exit(struct sock *sk)
 {
 	struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
 
-	ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
 	sk_stop_timer(sk, &hc->tx_no_feedback_timer);
-
 	tfrc_tx_hist_purge(&hc->tx_hist);
 }
 
 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
 {
-	struct ccid3_hc_tx_sock *hc;
-
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return;
-
-	hc = ccid3_hc_tx_sk(sk);
-	info->tcpi_rto = hc->tx_t_rto;
-	info->tcpi_rtt = hc->tx_rtt;
+	info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto;
+	info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt;
 }
 
 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
 				  u32 __user *optval, int __user *optlen)
 {
-	const struct ccid3_hc_tx_sock *hc;
+	const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
+	struct tfrc_tx_info tfrc;
 	const void *val;
 
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return -EINVAL;
-
-	hc = ccid3_hc_tx_sk(sk);
 	switch (optname) {
 	case DCCP_SOCKOPT_CCID_TX_INFO:
-		if (len < sizeof(hc->tx_tfrc))
+		if (len < sizeof(tfrc))
 			return -EINVAL;
-		len = sizeof(hc->tx_tfrc);
-		val = &hc->tx_tfrc;
+		tfrc.tfrctx_x	   = hc->tx_x;
+		tfrc.tfrctx_x_recv = hc->tx_x_recv;
+		tfrc.tfrctx_x_calc = hc->tx_x_calc;
+		tfrc.tfrctx_rtt	   = hc->tx_rtt;
+		tfrc.tfrctx_p	   = hc->tx_p;
+		tfrc.tfrctx_rto	   = hc->tx_t_rto;
+		tfrc.tfrctx_ipi	   = hc->tx_t_ipi;
+		len = sizeof(tfrc);
+		val = &tfrc;
 		break;
 	default:
 		return -ENOPROTOOPT;
@@ -624,7 +570,6 @@ static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
 	static const char *const ccid3_rx_state_names[] = {
 	[TFRC_RSTATE_NO_DATA] = "NO_DATA",
 	[TFRC_RSTATE_DATA]    = "DATA",
-	[TFRC_RSTATE_TERM]    = "TERM",
 	};
 
 	return ccid3_rx_state_names[state];
@@ -650,14 +595,9 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
 {
 	struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 	struct dccp_sock *dp = dccp_sk(sk);
-	ktime_t now;
+	ktime_t now = ktime_get_real();
 	s64 delta = 0;
 
-	if (unlikely(hc->rx_state == TFRC_RSTATE_TERM))
-		return;
-
-	now = ktime_get_real();
-
 	switch (fbtype) {
 	case CCID3_FBACK_INITIAL:
 		hc->rx_x_recv = 0;
@@ -701,14 +641,12 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
 
 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
 {
-	const struct ccid3_hc_rx_sock *hc;
+	const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 	__be32 x_recv, pinv;
 
 	if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
 		return 0;
 
-	hc = ccid3_hc_rx_sk(sk);
-
 	if (dccp_packet_without_ack(skb))
 		return 0;
 
@@ -749,10 +687,11 @@ static u32 ccid3_first_li(struct sock *sk)
 	x_recv = scaled_div32(hc->rx_bytes_recv, delta);
 	if (x_recv == 0) {		/* would also trigger divide-by-zero */
 		DCCP_WARN("X_recv==0\n");
-		if ((x_recv = hc->rx_x_recv) == 0) {
+		if (hc->rx_x_recv == 0) {
 			DCCP_BUG("stored value of X_recv is zero");
 			return ~0U;
 		}
+		x_recv = hc->rx_x_recv;
 	}
 
 	fval = scaled_div(hc->rx_s, hc->rx_rtt);
@@ -862,46 +801,31 @@ static void ccid3_hc_rx_exit(struct sock *sk)
 {
 	struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 
-	ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
-
 	tfrc_rx_hist_purge(&hc->rx_hist);
 	tfrc_lh_cleanup(&hc->rx_li_hist);
 }
 
 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
 {
-	const struct ccid3_hc_rx_sock *hc;
-
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return;
-
-	hc = ccid3_hc_rx_sk(sk);
-	info->tcpi_ca_state = hc->rx_state;
+	info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state;
 	info->tcpi_options  |= TCPI_OPT_TIMESTAMPS;
-	info->tcpi_rcv_rtt  = hc->rx_rtt;
+	info->tcpi_rcv_rtt  = ccid3_hc_rx_sk(sk)->rx_rtt;
 }
 
 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
 				  u32 __user *optval, int __user *optlen)
 {
-	const struct ccid3_hc_rx_sock *hc;
+	const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
 	struct tfrc_rx_info rx_info;
 	const void *val;
 
-	/* Listen socks doesn't have a private CCID block */
-	if (sk->sk_state == DCCP_LISTEN)
-		return -EINVAL;
-
-	hc = ccid3_hc_rx_sk(sk);
 	switch (optname) {
 	case DCCP_SOCKOPT_CCID_RX_INFO:
 		if (len < sizeof(rx_info))
 			return -EINVAL;
 		rx_info.tfrcrx_x_recv = hc->rx_x_recv;
 		rx_info.tfrcrx_rtt    = hc->rx_rtt;
-		rx_info.tfrcrx_p      = hc->rx_pinv == 0 ? ~0U :
-					   scaled_div(1, hc->rx_pinv);
+		rx_info.tfrcrx_p      = tfrc_invert_loss_event_rate(hc->rx_pinv);
 		len = sizeof(rx_info);
 		val = &rx_info;
 		break;