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samples: net: coap_server: Fix retransmission mechanism

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The retransmission handler only increased the retransmission count, w/o
sending the actual message again. Additionally, the next retransmission
time calculation was broken - it did not take into consideration the
time that has already passed since before retransmission, and re-applied
the entire timeout value.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
This commit is contained in:
Robert Lubos 2021-09-22 14:28:29 +02:00 • committed by Anas Nashif
commit 33677ef383
1 changed files with 35 additions and 8 deletions
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43
samples/net/sockets/coap_server/src/coap-server.c
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@ -38,6 +38,10 @@ LOG_MODULE_REGISTER(net_coap_server_sample, LOG_LEVEL_DBG);
{ { { 0x20, 0x01, 0x0d, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x1 } } }
#endif
#define ADDRLEN(sock) \
(((struct sockaddr *)sock)->sa_family == AF_INET ? \
sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6))
#define NUM_OBSERVERS 3
#define NUM_PENDINGS 3
@ -951,9 +955,30 @@ static int send_notification_packet(const struct sockaddr *addr,
const uint8_t *token, uint8_t tkl,
bool is_response);
static void schedule_next_retransmission(void)
{
struct coap_pending *pending;
int32_t remaining;
uint32_t now = k_uptime_get_32();
/* Get the first pending retansmission to expire after cycling. */
pending = coap_pending_next_to_expire(pendings, NUM_PENDINGS);
if (!pending) {
return;
}
remaining = pending->t0 + pending->timeout - now;
if (remaining < 0) {
remaining = 0;
}
k_work_reschedule(&retransmit_work, K_MSEC(remaining));
}
static void retransmit_request(struct k_work *work)
{
struct coap_pending *pending;
int r;
pending = coap_pending_next_to_expire(pendings, NUM_PENDINGS);
if (!pending) {
@ -963,10 +988,17 @@ static void retransmit_request(struct k_work *work)
if (!coap_pending_cycle(pending)) {
k_free(pending->data);
coap_pending_clear(pending);
return;
} else {
net_hexdump("Retransmit", pending->data, pending->len);
r = sendto(sock, pending->data, pending->len, 0,
&pending->addr, ADDRLEN(&pending->addr));
if (r < 0) {
LOG_ERR("Failed to send %d", errno);
}
}
k_work_reschedule(&retransmit_work, K_MSEC(pending->timeout));
schedule_next_retransmission();
}
static void update_counter(struct k_work *work)
@ -999,12 +1031,7 @@ static int create_pending_request(struct coap_packet *response,
coap_pending_cycle(pending);
pending = coap_pending_next_to_expire(pendings, NUM_PENDINGS);
if (!pending) {
return 0;
}
k_work_reschedule(&retransmit_work, K_MSEC(pending->timeout));
schedule_next_retransmission();
return 0;
}