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serialqueue: Fix off-by-one error in retransmit sequence number tracking 

Track the sequence number of the message last retransmitted (not the
sequence number of the next message to be transmitted).  This fixes a
small possibility of a valid nak not being honored.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2017-07-21 23:43:48 -04:00
parent 61325c0a14
commit 4655a6bfef
1 changed files with 3 additions and 3 deletions
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6
klippy/serialqueue.c
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@ -448,7 +448,7 @@ update_receive_seq(struct serialqueue *sq, double eventtime, uint64_t rseq)
pollreactor_update_timer(&sq->pr, SQPT_COMMAND, PR_NOW); pollreactor_update_timer(&sq->pr, SQPT_COMMAND, PR_NOW);
// Update retransmit info // Update retransmit info
if (sq->rtt_sample_seq && rseq >= sq->rtt_sample_seq if (sq->rtt_sample_seq && rseq > sq->rtt_sample_seq
&& sq->last_receive_sent_time) { && sq->last_receive_sent_time) {
// RFC6298 rtt calculations // RFC6298 rtt calculations
double delta = eventtime - sq->last_receive_sent_time; double delta = eventtime - sq->last_receive_sent_time;
@ -586,7 +586,7 @@ retransmit_event(struct serialqueue *sq, double eventtime)
if (sq->rto > MAX_RTO) if (sq->rto > MAX_RTO)
sq->rto = MAX_RTO; sq->rto = MAX_RTO;
} }
sq->retransmit_seq = sq->send_seq; sq->retransmit_seq = sq->send_seq - 1;
sq->rtt_sample_seq = 0; sq->rtt_sample_seq = 0;
if (eventtime > sq->idle_time) if (eventtime > sq->idle_time)
sq->idle_time = eventtime; sq->idle_time = eventtime;
@ -654,9 +654,9 @@ build_and_send_command(struct serialqueue *sq, double eventtime)
if (list_empty(&sq->sent_queue)) if (list_empty(&sq->sent_queue))
pollreactor_update_timer(&sq->pr, SQPT_RETRANSMIT pollreactor_update_timer(&sq->pr, SQPT_RETRANSMIT
, sq->idle_time + sq->rto); , sq->idle_time + sq->rto);
sq->send_seq++;
if (!sq->rtt_sample_seq) if (!sq->rtt_sample_seq)
sq->rtt_sample_seq = sq->send_seq; sq->rtt_sample_seq = sq->send_seq;
sq->send_seq++;
list_add_tail(&out->node, &sq->sent_queue); list_add_tail(&out->node, &sq->sent_queue);
} }