Using sendmsg_current to detect if a packet needs to be retransmitted is
brittle as only packets containing data will ever be considered, packets
only containing a header (without data) were never being retransmitted.
The sendbuf_len is used to determine if a packets is being send or not,
a non-zero length means that a packets is still being in the "try-send"
state, the length is not set to zero when a valid SN is received.
Retransmission issue can be easily reproduced with a physical UART (not
cdc_acm over USB), by running the following command:
while ratp-barebox-cli -b 115200 -t /dev/ttyACMx -p; do :; done
Alternatively, it is possible to modify lib/ratp.c to force packets to
be sent by the retransmission logic with the following change:
@ int ratp_send_pkt(struct ratp_internal *ri, void *pkt, int length)
ri->sendbuf_len = length;
- ri->retransmission_timer_start = get_time_ns();
+ ri->retransmission_timer_start = get_time_ns() - ri->rto *
MSECOND/2;
ri->retransmission_count = 0;
}
- return ri->ratp->send(ri->ratp, pkt, length);
+ return 0;
Signed-off-by: Jules Maselbas <[email protected]>
---
lib/ratp.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/lib/ratp.c b/lib/ratp.c
index ce30223bac..d5205a4e93 100644
--- a/lib/ratp.c
+++ b/lib/ratp.c
@@ -738,7 +738,7 @@ static int ratp_behaviour_c2(struct ratp_internal *ri, void
*pkt)
control = RATP_CONTROL_RST | RATP_CONTROL_ACK |
ratp_set_sn(ratp_an(hdr)) |
ratp_set_next_an(ratp_sn(hdr));
ratp_send_hdr(ri, control);
-
+ ri->sendbuf_len = 0;
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
@@ -784,7 +784,7 @@ static int ratp_behaviour_d1(struct ratp_internal *ri, void
*pkt)
ri->status = -ECONNREFUSED;
pr_debug("Error: connection refused\n");
-
+ ri->sendbuf_len = 0;
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
@@ -812,6 +812,8 @@ static int ratp_behaviour_d2(struct ratp_internal *ri, void
*pkt)
ri->status = -ECONNRESET;
pr_debug("connection reset\n");
+ ri->sendbuf_len = 0;
+ ratp_state_change(ri, RATP_STATE_CLOSED);
return 0;
}
@@ -879,7 +881,7 @@ static int ratp_behaviour_e(struct ratp_internal *ri, void
*pkt)
ratp_send_hdr(ri, control);
pr_debug("connection reset\n");
-
+ ri->sendbuf_len = 0;
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
@@ -924,8 +926,10 @@ static int ratp_behaviour_f1(struct ratp_internal *ri,
void *pkt)
if (!(hdr->control & RATP_CONTROL_ACK))
return 1;
- if (ratp_an_expected(ri, hdr))
+ if (ratp_an_expected(ri, hdr)) {
+ ri->sendbuf_len = 0; /* packet succesfully received */
return 0;
+ }
control = RATP_CONTROL_RST | ratp_set_sn(ratp_an(hdr));
ratp_send_hdr(ri, control);
@@ -971,6 +975,7 @@ static int ratp_behaviour_f2(struct ratp_internal *ri, void
*pkt)
if (ri->sendmsg_current)
ratp_msg_done(ri, ri->sendmsg_current, 0);
ri->sendmsg_current = NULL;
+ ri->sendbuf_len = 0; /* packet succesfully received */
return 0;
} else {
pr_vdebug("%s: an not expected\n", __func__);
@@ -1175,6 +1180,7 @@ static int ratp_behaviour_h3(struct ratp_internal *ri,
void *pkt)
ratp_send_hdr(ri, control);
ri->status = -ECONNRESET;
pr_debug("Error: Connection reset\n");
+ ri->sendbuf_len = 0;
ratp_state_change(ri, RATP_STATE_CLOSED);
return 1;
}
@@ -1217,8 +1223,10 @@ static int ratp_behaviour_h4(struct ratp_internal *ri,
void *pkt)
pr_debug("%s\n", __func__);
- if (ratp_an_expected(ri, hdr))
+ if (ratp_an_expected(ri, hdr)) {
+ ri->sendbuf_len = 0; /* packet succesfully received */
ratp_state_change(ri, RATP_STATE_CLOSED);
+ }
return 1;
}
@@ -1244,6 +1252,7 @@ static int ratp_behaviour_h5(struct ratp_internal *ri,
void *pkt)
pr_debug("%s\n", __func__);
if (ratp_an_expected(ri, hdr)) {
+ ri->sendbuf_len = 0; /* packet succesfully received */
ratp_state_change(ri, RATP_STATE_TIME_WAIT);
ratp_start_time_wait_timer(ri);
}
@@ -1580,9 +1589,8 @@ int ratp_poll(struct ratp *ratp)
}
}
- if (ri->sendmsg_current && is_timeout(ri->retransmission_timer_start,
+ if (ri->sendbuf_len && is_timeout(ri->retransmission_timer_start,
ri->rto * MSECOND)) {
-
ri->retransmission_count++;
if (ri->retransmission_count == ri->max_retransmission) {
ri->status = ret = -ETIMEDOUT;
@@ -1601,7 +1609,7 @@ int ratp_poll(struct ratp *ratp)
goto out;
}
- if (!ri->sendmsg_current && !list_empty(&ri->sendmsg))
+ if (ri->sendbuf_len == 0 && !list_empty(&ri->sendmsg))
ratp_send_next_data(ri);
ret = 0;
--
2.17.1
