forked from luck/tmp_suning_uos_patched
dccp ccid-3: Fix a loss detection bug
This fixes a bug in the logic of the TFRC loss detection: * new_loss_indicated() should not be called while a loss is pending; * but the code allows this; * thus, for two subsequent gaps in the sequence space, when loss_count has not yet reached NDUPACK=3, the loss_count is falsely reduced to 1. To avoid further and similar problems, all loss handling and loss detection is now done inside tfrc_rx_hist_handle_loss(), using an appropriate routine to track new losses. Further changes: ---------------- * added a reminder that no RX history operations should be performed when rx_handle_loss() has identified a (new) loss, since the function takes care of packet reordering during loss detection; * made tfrc_rx_hist_loss_pending() bool (thanks to an earlier suggestion by Arnaldo); * removed unused functions. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This commit is contained in:
parent
5b5d0e7048
commit
b552c6231f
|
@ -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
|
||||
|
|
|
@ -206,10 +206,21 @@ 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,
|
||||
|
@ -353,6 +364,9 @@ 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,
|
||||
|
@ -361,7 +375,9 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
|
|||
{
|
||||
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);
|
||||
|
|
|
@ -118,30 +118,10 @@ 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)
|
||||
static inline bool 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)
|
||||
{
|
||||
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,
|
||||
|
|
Loading…
Reference in New Issue
Block a user