Merge pull request #20725 from fabian18/pr/nanocoap_sock_fix_ctx_release

nanocoap/sock: fix state handling for mismatching message ID in `nanocoap_sock_request_cb()`

sys/net/application_layer/nanocoap/sock.c

@@ -54,7 +54,7 @@
 enum {
  STATE_REQUEST_SEND, /**< request was just sent or will be sent again */
  STATE_STOP_RETRANSMIT, /**< stop retransmissions due to a matching empty ACK */
- STATE_RESPONSE_OK,  /**< valid response was received  */
+ STATE_WAIT_RESPONSE, /**< waiting for a response */
 };
 
 typedef struct {
@@ -234,19 +234,21 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
  res = _sock_sendv(sock, &head);
  if (res <= 0) {
  DEBUG("nanocoap: error sending coap request, %" PRIdSIZE "\n", res);
- return res;
+ goto release;
  }
 
  /* no response needed and no response handler given */
  if (!confirmable && !cb) {
- return 0;
+ res = 0;
+ goto release;
  }
 
  /* ctx must have been released at this point */
  assert(ctx == NULL);
+ state = STATE_WAIT_RESPONSE;
  /* fall-through */
- case STATE_STOP_RETRANSMIT:
- case STATE_RESPONSE_OK:
+ case STATE_WAIT_RESPONSE: /* waiting for response, no empty ACK received */
+ case STATE_STOP_RETRANSMIT: /* waiting for response, empty ACK received */
  if (ctx == NULL) {
  DEBUG("nanocoap: waiting for response (timeout: %"PRIu32" µs)\n",
  _deadline_left_us(deadline));
@@ -267,25 +269,23 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
  /* no more data */
  /* sock_udp_recv_buf() needs to be called in a loop until ctx is NULL again
  * to release the buffer */
- if (state == STATE_STOP_RETRANSMIT) {
- continue;
- }
- return res;
+ continue;
  }
  res = tmp;
  if (res == -ETIMEDOUT) {
  if (tries_left == 0) {
  DEBUG("nanocoap: maximum retries reached\n");
- return -ETIMEDOUT;
+ goto release;
  }
+ state = STATE_REQUEST_SEND;
  DEBUG("nanocoap: timeout waiting for response\n");
  timeout *= 2;
  deadline = _deadline_from_interval(timeout);
  continue;
  }
  if (res < 0) {
  DEBUG("nanocoap: error receiving CoAP response, %" PRIdSIZE "\n", res);
- return res;
+ goto release;
  }
 
  /* parse response */
@@ -297,13 +297,8 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
  DEBUG("nanocoap: ID mismatch, got %u want %u\n", coap_get_id(pkt), id);
  continue;
  }
-
  DEBUG("nanocoap: response code=%i\n", coap_get_code_decimal(pkt));
  switch (coap_get_type(pkt)) {
- case COAP_TYPE_RST:
- /* TODO: handle different? */
- res = -EBADMSG;
- break;
  case COAP_TYPE_ACK:
  if (coap_get_code_raw(pkt) == COAP_CODE_EMPTY) {
  /* empty ACK, wait for separate response */
@@ -315,24 +310,34 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
  continue;
  }
  /* fall-through */
+ case COAP_TYPE_RST:
  case COAP_TYPE_CON:
  case COAP_TYPE_NON:
- state = STATE_RESPONSE_OK;
+ if (coap_get_type(pkt) == COAP_TYPE_RST) {
+ /* think about whether cb should be called on RST as well */
+ res = -EBADMSG;
+ goto release;
+ }
  if (coap_get_type(pkt) == COAP_TYPE_CON) {
- /* send ACK */
  _send_ack(sock, pkt);
  }
- /* call user callback */
  if (cb) {
  res = cb(arg, pkt);
- } else {
+ }
+ else {
  res = _get_error(pkt);
  }
- break;
+ goto release;
  }
  }
  }
 
+release:
+ while (ctx) {
+ /* make sure ctx is really deleted in all cases */
+ _sock_recv_buf(sock, &payload, &ctx, 0);
+ }
+
  return res;
 }