4 files changed, 67 insertions, 90 deletions

diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index a1929f33d703..f6756e0c9e69 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -794,7 +794,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
 {
         struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
         enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
-        const u32 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
+        const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
         const bool is_data_packet = dccp_data_packet(skb);
 
         if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)) {
@@ -825,18 +825,16 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
         }
 
         /*
-         * Handle pending losses and otherwise check for new loss
+         * Perform loss detection and handle pending losses
          */
-        if (tfrc_rx_hist_loss_pending(&hcrx->ccid3hcrx_hist) &&
-            tfrc_rx_handle_loss(&hcrx->ccid3hcrx_hist,
-                                &hcrx->ccid3hcrx_li_hist,
-                                skb, ndp, ccid3_first_li, sk) ) {
+        if (tfrc_rx_handle_loss(&hcrx->ccid3hcrx_hist, &hcrx->ccid3hcrx_li_hist,
+                                skb, ndp, ccid3_first_li, sk)) {
                 do_feedback = CCID3_FBACK_PARAM_CHANGE;
                 goto done_receiving;
         }
 
-        if (tfrc_rx_hist_new_loss_indicated(&hcrx->ccid3hcrx_hist, skb, ndp))
-                goto update_records;
+        if (tfrc_rx_hist_loss_pending(&hcrx->ccid3hcrx_hist))
+                return; /* done receiving */
 
         /*
          * Handle data packets: RTT sampling and monitoring p
diff --git a/net/dccp/ccids/lib/loss_interval.c b/net/dccp/ccids/lib/loss_interval.c
index 849e181e698f..bcd6ac415bb9 100644
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
@@ -90,14 +90,14 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
 {
         struct tfrc_loss_interval *cur = tfrc_lh_peek(lh);
         u32 old_i_mean = lh->i_mean;
-        s64 length;
+        s64 len;
 
         if (cur == NULL)                        /* not initialised */
                 return 0;
 
-        length = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq);
+        len = dccp_delta_seqno(cur->li_seqno, DCCP_SKB_CB(skb)->dccpd_seq) + 1;
 
-        if (length - cur->li_length <= 0)       /* duplicate or reordered */
+        if (len - (s64)cur->li_length <= 0)     /* duplicate or reordered */
                 return 0;
 
         if (SUB16(dccp_hdr(skb)->dccph_ccval, cur->li_ccval) > 4)
@@ -114,7 +114,7 @@ u8 tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *skb)
         if (tfrc_lh_length(lh) == 1)            /* due to RFC 3448, 6.3.1 */
                 return 0;
 
-        cur->li_length = length;
+        cur->li_length = len;
         tfrc_lh_calc_i_mean(lh);
 
         return (lh->i_mean < old_i_mean);
@@ -159,7 +159,7 @@ int tfrc_lh_interval_add(struct tfrc_loss_hist *lh, struct tfrc_rx_hist *rh,
         else {
                 cur->li_length = dccp_delta_seqno(cur->li_seqno, new->li_seqno);
                 new->li_length = dccp_delta_seqno(new->li_seqno,
-                                  tfrc_rx_hist_last_rcv(rh)->tfrchrx_seqno);
+                                  tfrc_rx_hist_last_rcv(rh)->tfrchrx_seqno) + 1;
                 if (lh->counter > (2*LIH_SIZE))
                         lh->counter -= LIH_SIZE;
 
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 20af1a693427..6cc108afdc3b 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -153,7 +153,7 @@ void tfrc_rx_packet_history_exit(void)
 
 static inline void tfrc_rx_hist_entry_from_skb(struct tfrc_rx_hist_entry *entry,
                                                const struct sk_buff *skb,
-                                               const u32 ndp)
+                                               const u64 ndp)
 {
         const struct dccp_hdr *dh = dccp_hdr(skb);
 
@@ -166,7 +166,7 @@ static inline void tfrc_rx_hist_entry_from_skb(struct tfrc_rx_hist_entry *entry,
 
 void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
                              const struct sk_buff *skb,
-                             const u32 ndp)
+                             const u64 ndp)
 {
         struct tfrc_rx_hist_entry *entry = tfrc_rx_hist_last_rcv(h);
 
@@ -206,31 +206,39 @@ static void tfrc_rx_hist_swap(struct tfrc_rx_hist *h, const u8 a, const u8 b)
  *
  * In the descriptions, `Si' refers to the sequence number of entry number i,
  * whose NDP count is `Ni' (lower case is used for variables).
- * Note: All __after_loss functions expect that a test against duplicates has
- *       been performed already: the seqno of the skb must not be less than the
- *       seqno of loss_prev; and it must not equal that of any valid hist_entry.
+ * Note: All __xxx_loss functions expect that a test against duplicates has been
+ *       performed already: the seqno of the skb must not be less than the seqno
+ *       of loss_prev; and it must not equal that of any valid history entry.
  */
+static void __do_track_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u64 n1)
+{
+        u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
+            s1 = DCCP_SKB_CB(skb)->dccpd_seq;
+
+        if (!dccp_loss_free(s0, s1, n1)) {      /* gap between S0 and S1 */
+                h->loss_count = 1;
+                tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 1), skb, n1);
+        }
+}
+
 static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2)
 {
         u64 s0 = tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno,
             s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
             s2 = DCCP_SKB_CB(skb)->dccpd_seq;
-        int n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp,
-           d12 = dccp_delta_seqno(s1, s2), d2;
 
-        if (d12 > 0) {                  /* S1  <  S2 */
+        if (likely(dccp_delta_seqno(s1, s2) > 0)) {     /* S1  <  S2 */
                 h->loss_count = 2;
                 tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 2), skb, n2);
                 return;
         }
 
         /* S0  <  S2  <  S1 */
-        d2 = dccp_delta_seqno(s0, s2);
 
-        if (d2 == 1 || n2 >= d2) {      /* S2 is direct successor of S0 */
-                int d21 = -d12;
+        if (dccp_loss_free(s0, s2, n2)) {
+                u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
 
-                if (d21 == 1 || n1 >= d21) {
+                if (dccp_loss_free(s2, s1, n1)) {
                         /* hole is filled: S0, S2, and S1 are consecutive */
                         h->loss_count = 0;
                         h->loss_start = tfrc_rx_hist_index(h, 1);
@@ -238,9 +246,9 @@ static void __one_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n2
                         /* gap between S2 and S1: just update loss_prev */
                         tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_loss_prev(h), skb, n2);
 
-        } else {                        /* hole between S0 and S2 */
+        } else {        /* gap between S0 and S2 */
                 /*
-                 * Reorder history to insert S2 between S0 and s1
+                 * Reorder history to insert S2 between S0 and S1
                  */
                 tfrc_rx_hist_swap(h, 0, 3);
                 h->loss_start = tfrc_rx_hist_index(h, 3);
@@ -256,22 +264,18 @@ static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3)
             s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
             s2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_seqno,
             s3 = DCCP_SKB_CB(skb)->dccpd_seq;
-        int n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp,
-           d23 = dccp_delta_seqno(s2, s3), d13, d3, d31;
 
-        if (d23 > 0) {                  /* S2  <  S3 */
+        if (likely(dccp_delta_seqno(s2, s3) > 0)) {     /* S2  <  S3 */
                 h->loss_count = 3;
                 tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 3), skb, n3);
                 return 1;
         }
 
         /* S3  <  S2 */
-        d13 = dccp_delta_seqno(s1, s3);
 
-        if (d13 > 0) {
+        if (dccp_delta_seqno(s1, s3) > 0) {             /* S1  <  S3  <  S2 */
                 /*
-                 * The sequence number order is S1, S3, S2
-                 * Reorder history to insert entry between S1 and S2
+                 * Reorder history to insert S3 between S1 and S2
                  */
                 tfrc_rx_hist_swap(h, 2, 3);
                 tfrc_rx_hist_entry_from_skb(tfrc_rx_hist_entry(h, 2), skb, n3);
@@ -280,17 +284,15 @@ static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3)
         }
 
         /* S0  <  S3  <  S1 */
-        d31 = -d13;
-        d3  = dccp_delta_seqno(s0, s3);
 
-        if (d3 == 1 || n3 >= d3) {      /* S3 is a successor of S0 */
+        if (dccp_loss_free(s0, s3, n3)) {
+                u64 n1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_ndp;
 
-                if (d31 == 1 || n1 >= d31) {
+                if (dccp_loss_free(s3, s1, n1)) {
                         /* hole between S0 and S1 filled by S3 */
-                        int  d2 = dccp_delta_seqno(s1, s2),
-                             n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp;
+                        u64 n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp;
 
-                        if (d2 == 1 || n2 >= d2) {
+                        if (dccp_loss_free(s1, s2, n2)) {
                                 /* entire hole filled by S0, S3, S1, S2 */
                                 h->loss_start = tfrc_rx_hist_index(h, 2);
                                 h->loss_count = 0;
@@ -307,8 +309,8 @@ static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3)
         }
 
         /*
-         * The remaining case: S3 is not a successor of S0.
-         * Sequence order is S0, S3, S1, S2; reorder to insert between S0 and S1
+         * The remaining case:  S0  <  S3  <  S1  <  S2;  gap between S0 and S3
+         * Reorder history to insert S3 between S0 and S1.
          */
         tfrc_rx_hist_swap(h, 0, 3);
         h->loss_start = tfrc_rx_hist_index(h, 3);
@@ -318,33 +320,25 @@ static int __two_after_loss(struct tfrc_rx_hist *h, struct sk_buff *skb, u32 n3)
         return 1;
 }
 
-/* return the signed modulo-2^48 sequence number distance from entry e1 to e2 */
-static s64 tfrc_rx_hist_delta_seqno(struct tfrc_rx_hist *h, u8 e1, u8 e2)
-{
-        DCCP_BUG_ON(e1 > h->loss_count || e2 > h->loss_count);
-
-        return dccp_delta_seqno(tfrc_rx_hist_entry(h, e1)->tfrchrx_seqno,
-                                tfrc_rx_hist_entry(h, e2)->tfrchrx_seqno);
-}
-
 /* recycle RX history records to continue loss detection if necessary */
 static void __three_after_loss(struct tfrc_rx_hist *h)
 {
         /*
-         * The distance between S0 and S1 is always greater than 1 and the NDP
-         * count of S1 is smaller than this distance. Otherwise there would
-         * have been no loss. Hence it is only necessary to see whether there
-         * are further missing data packets between S1/S2 and S2/S3.
+         * At this stage we know already that there is a gap between S0 and S1
+         * (since S0 was the highest sequence number received before detecting
+         * the loss). To recycle the loss record, it is thus only necessary to
+         * check for other possible gaps between S1/S2 and between S2/S3.
          */
-        int d2 = tfrc_rx_hist_delta_seqno(h, 1, 2),
-            d3 = tfrc_rx_hist_delta_seqno(h, 2, 3),
-            n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp,
+        u64 s1 = tfrc_rx_hist_entry(h, 1)->tfrchrx_seqno,
+            s2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_seqno,
+            s3 = tfrc_rx_hist_entry(h, 3)->tfrchrx_seqno;
+        u64 n2 = tfrc_rx_hist_entry(h, 2)->tfrchrx_ndp,
             n3 = tfrc_rx_hist_entry(h, 3)->tfrchrx_ndp;
 
-        if (d2 == 1 || n2 >= d2) {      /* S2 is successor to S1 */
+        if (dccp_loss_free(s1, s2, n2)) {
 
-                if (d3 == 1 || n3 >= d3) {
-                        /* S3 is successor of S2: entire hole is filled */
+                if (dccp_loss_free(s2, s3, n3)) {
+                        /* no gap between S2 and S3: entire hole is filled */
                         h->loss_start = tfrc_rx_hist_index(h, 3);
                         h->loss_count = 0;
                 } else {
@@ -353,7 +347,7 @@ static void __three_after_loss(struct tfrc_rx_hist *h)
                         h->loss_count = 1;
                 }
 
-        } else {                        /* gap between S1 and S2 */
+        } else {        /* gap between S1 and S2 */
                 h->loss_start = tfrc_rx_hist_index(h, 1);
                 h->loss_count = 2;
         }
@@ -370,15 +364,20 @@ static void __three_after_loss(struct tfrc_rx_hist *h)
  *  Chooses action according to pending loss, updates LI database when a new
  *  loss was detected, and does required post-processing. Returns 1 when caller
  *  should send feedback, 0 otherwise.
+ *  Since it also takes care of reordering during loss detection and updates the
+ *  records accordingly, the caller should not perform any more RX history
+ *  operations when loss_count is greater than 0 after calling this function.
  */
 int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
                         struct tfrc_loss_hist *lh,
-                        struct sk_buff *skb, u32 ndp,
+                        struct sk_buff *skb, const u64 ndp,
                         u32 (*calc_first_li)(struct sock *), struct sock *sk)
 {
         int is_new_loss = 0;
 
-        if (h->loss_count == 1) {
+        if (h->loss_count == 0) {
+                __do_track_loss(h, skb, ndp);
+        } else if (h->loss_count == 1) {
                 __one_after_loss(h, skb, ndp);
         } else if (h->loss_count != 2) {
                 DCCP_BUG("invalid loss_count %d", h->loss_count);
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index c7eeda49cb20..461cc91cce88 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -64,7 +64,7 @@ struct tfrc_rx_hist_entry {
         u64              tfrchrx_seqno:48,
                          tfrchrx_ccval:4,
                          tfrchrx_type:4;
-        u32              tfrchrx_ndp; /* In fact it is from 8 to 24 bits */
+        u64              tfrchrx_ndp:48;
         ktime_t          tfrchrx_tstamp;
 };
 
@@ -118,41 +118,21 @@ static inline struct tfrc_rx_hist_entry *
         return h->ring[h->loss_start];
 }
 
-/* initialise loss detection and disable RTT sampling */
-static inline void tfrc_rx_hist_loss_indicated(struct tfrc_rx_hist *h)
-{
-        h->loss_count = 1;
-}
-
 /* indicate whether previously a packet was detected missing */
-static inline int tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
-{
-        return h->loss_count;
-}
-
-/* any data packets missing between last reception and skb ? */
-static inline int tfrc_rx_hist_new_loss_indicated(struct tfrc_rx_hist *h,
-                                                  const struct sk_buff *skb,
-                                                  u32 ndp)
+static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
 {
-        int delta = dccp_delta_seqno(tfrc_rx_hist_last_rcv(h)->tfrchrx_seqno,
-                                     DCCP_SKB_CB(skb)->dccpd_seq);
-
-        if (delta > 1 && ndp < delta)
-                tfrc_rx_hist_loss_indicated(h);
-
-        return tfrc_rx_hist_loss_pending(h);
+        return h->loss_count > 0;
 }
 
 extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
-                                    const struct sk_buff *skb, const u32 ndp);
+                                    const struct sk_buff *skb, const u64 ndp);
 
 extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
 
 struct tfrc_loss_hist;
 extern int  tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
                                 struct tfrc_loss_hist *lh,
-                                struct sk_buff *skb, u32 ndp,
+                                struct sk_buff *skb, const u64 ndp,
                                 u32 (*first_li)(struct sock *sk),
                                 struct sock *sk);
 extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,