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net/gcoap: deregister confirmable notification
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Handles if no ACK response, or if a reset (RST) response.
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@kb2ma
kb2ma committed Apr 3, 2018
1 parent baeb3e8 commit ac71683
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Showing 2 changed files with 50 additions and 19 deletions.
5 changes: 3 additions & 2 deletions sys/include/net/gcoap.h
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Original file line number Diff line number Diff line change
Expand Up @@ -159,8 +159,9 @@
* GCOAP_OBS_VALUE_WIDTH.
*
* To cancel a notification, the server expects to receive a GET request with
* the Observe option value set to 1. The server does not support cancellation
* via a reset (RST) response to a non-confirmable notification.
* the Observe option value set to 1. A confirmable notification also is
* cancelled by a reset (RST) response from the client or by the absence of an
* ACK response.
*
* ## Implementation Notes ##
*
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64 changes: 47 additions & 17 deletions sys/net/application_layer/gcoap/gcoap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -44,11 +44,13 @@ static void _find_req_memo(gcoap_request_memo_t **memo_ptr, coap_pkt_t *pdu,
const sock_udp_ep_t *remote, int match_type);
static void _find_resource(coap_pkt_t *pdu, coap_resource_t **resource_ptr,
gcoap_listener_t **listener_ptr);
static int _find_observer(sock_udp_ep_t **observer, sock_udp_ep_t *remote);
static int _find_obs_memo(gcoap_observe_memo_t **memo, sock_udp_ep_t *remote,
static int _find_observer(sock_udp_ep_t **observer, const sock_udp_ep_t *remote);
static int _find_obs_memo(gcoap_observe_memo_t **memo, const sock_udp_ep_t *remote,
uint8_t *token, int token_len);
static void _find_obs_memo_resource(gcoap_observe_memo_t **memo,
const coap_resource_t *resource);
static void _clear_obs_memo(gcoap_observe_memo_t *memo,
const sock_udp_ep_t *remote);

/* Internal variables */
const coap_resource_t _default_resources[] = {
Expand Down Expand Up @@ -192,8 +194,10 @@ static void _listen(sock_udp_t *sock)
if (pdu.hdr->code == COAP_CODE_EMPTY) {
_find_req_memo(&memo, &pdu, &remote, GCOAP_FIND_REQ_MSGID);
if (memo) {
/* empty ACK for confirmable request */
if (coap_get_type(&pdu) == COAP_TYPE_ACK && memo->send_limit >= 0) {
/* empty ACK/reset for confirmable request */
if (((coap_get_type(&pdu) == COAP_TYPE_ACK)
|| (coap_get_type(&pdu) == COAP_TYPE_RST))
&& memo->send_limit >= 0) {
/* For an observe notification ACK from the client, no further
* response expected. Clear the request memo. */
gcoap_observe_memo_t *obs_memo = NULL;
Expand All @@ -203,6 +207,9 @@ static void _listen(sock_udp_t *sock)
_find_obs_memo(&obs_memo, &remote, token, token_len);
if (obs_memo) {
xtimer_remove(&memo->response_timer);
if (coap_get_type(&pdu) == COAP_TYPE_RST) {
_clear_obs_memo(obs_memo, &memo->remote_ep);
}
*memo->msg.data.pdu_buf = 0; /* clear resend PDU buffer */
memo->state = GCOAP_MEMO_UNUSED;
}
Expand Down Expand Up @@ -343,16 +350,7 @@ static size_t _handle_req(coap_pkt_t *pdu, uint8_t *buf, size_t len,
_find_obs_memo(&memo, remote, pdu->token, coap_get_token_len(pdu));
/* clear memo, and clear observer if no other memos */
if (memo != NULL) {
DEBUG("gcoap: Deregistering observer for: %s\n", memo->resource->path);
memo->observer = NULL;
memo = NULL;
_find_obs_memo(&memo, remote, NULL, -1);
if (memo == NULL) {
_find_observer(&observer, remote);
if (observer != NULL) {
observer->family = AF_UNSPEC;
}
}
_clear_obs_memo(memo, remote);
}
coap_clear_observe(pdu);

Expand Down Expand Up @@ -488,7 +486,10 @@ static void _find_req_memo(gcoap_request_memo_t **memo_ptr, coap_pkt_t *src_pdu,
}
}

/* Calls handler callback on receipt of a timeout message. */
/*
* Calls handler callback on receipt of a timeout message. Also clears observe
* memo, if any, if the request was confirmable.
*/
static void _expire_request(gcoap_request_memo_t *memo)
{
DEBUG("coap: received timeout message\n");
Expand All @@ -506,6 +507,15 @@ static void _expire_request(gcoap_request_memo_t *memo)
memo->resp_handler(memo->state, &req, NULL);
}
if (memo->send_limit != GCOAP_SEND_LIMIT_NON) {
gcoap_observe_memo_t *obs_memo = NULL;
coap_hdr_t *req_hdr = (coap_hdr_t *)memo->msg.data.pdu_buf;
unsigned token_len = req_hdr->ver_t_tkl & 0xf;
uint8_t *token = token_len > 0 ? &req_hdr->data[0] : NULL;

_find_obs_memo(&obs_memo, &memo->remote_ep, token, token_len);
if (obs_memo != NULL) {
_clear_obs_memo(obs_memo, &memo->remote_ep);
}
*memo->msg.data.pdu_buf = 0; /* clear resend buffer */
}
memo->state = GCOAP_MEMO_UNUSED;
Expand Down Expand Up @@ -621,7 +631,7 @@ static bool _endpoints_equal(const sock_udp_ep_t *ep1, const sock_udp_ep_t *ep2)
* return Index of empty slot, suitable for registering new observer; or -1
* if no empty slots. Undefined if observer found.
*/
static int _find_observer(sock_udp_ep_t **observer, sock_udp_ep_t *remote)
static int _find_observer(sock_udp_ep_t **observer, const sock_udp_ep_t *remote)
{
int empty_slot = -1;
*observer = NULL;
Expand Down Expand Up @@ -649,7 +659,7 @@ static int _find_observer(sock_udp_ep_t **observer, sock_udp_ep_t *remote)
* return Index of empty slot, suitable for registering new memo; or -1 if no
* empty slots. Undefined if memo found.
*/
static int _find_obs_memo(gcoap_observe_memo_t **memo, sock_udp_ep_t *remote,
static int _find_obs_memo(gcoap_observe_memo_t **memo, const sock_udp_ep_t *remote,
uint8_t *token, int token_len)
{
int empty_slot = -1;
Expand Down Expand Up @@ -702,6 +712,26 @@ static void _find_obs_memo_resource(gcoap_observe_memo_t **memo,
}
}

/* Clear memo, and clear observer if no other memos. */
static void _clear_obs_memo(gcoap_observe_memo_t *memo,
const sock_udp_ep_t *remote)
{
assert(memo != NULL);
sock_udp_ep_t *observer = NULL;

memo->observer = NULL;
DEBUG("gcoap: Deregistered observer for: %s\n", memo->resource->path);

memo = NULL;
_find_obs_memo(&memo, remote, NULL, -1);
if (memo == NULL) {
_find_observer(&observer, remote);
if (observer != NULL) {
observer->family = AF_UNSPEC;
}
}
}

/*
* gcoap interface functions
*/
Expand Down

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