mirror of
https://github.com/obgm/libcoap.git
synced 2026-11-09 10:32:53 +03:00
Jon Shallow
7a4d2db8f3
Code works as expected for confirmable observes as the sent pdu is
retained for potential re-transmission.
For non-confirmable observes, the RST is seen in the response packet but
previously had no way of finding the observe/subscription to cancel.
Keep the last sent message id in coap_subscription_t (as tid) and when the
RST comes in, search for the subscription that has the same message id as
the pdu and remove that subscription.
include/coap2/subscribe.h:
Add in tid to coap_subscription_t (as per coap_pdu_t).
src/net.c:
Match tid in incoming RST pdu with a subscription. If found, delete the
subscription.
src/resource.c:
Save tid in both pdu and subscription when sending off an observe response.
To test code, make the following temporary change to coap-client
diff --git a/examples/client.c b/examples/client.c
index 4d3e4c7..0020b68 100644
--- a/examples/client.c
+++ b/examples/client.c
@@ -348,7 +348,8 @@ message_handler(struct coap_context_t *ctx,
#endif
/* check if this is a response to our original request */
- if (!check_token(received)) {
+static int count = 0;
+ if (!check_token(received) || ++count == 5) {
/* drop if this was just some message, or send RST in case of notification */
if (!sent && (received->type == COAP_MESSAGE_CON ||
received->type == COAP_MESSAGE_NON))
and run (coap-server running on the same host)
coap-client -N -s 10 coap://127.0.0.1/time
78 lines
2.4 KiB
C
78 lines
2.4 KiB
C
/*
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* subscribe.h -- subscription handling for CoAP
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* see RFC7641
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*
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* Copyright (C) 2010-2012,2014-2015 Olaf Bergmann <bergmann@tzi.org>
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*
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* This file is part of the CoAP library libcoap. Please see README for terms
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* of use.
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*/
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#ifndef COAP_SUBSCRIBE_H_
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#define COAP_SUBSCRIBE_H_
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#include "address.h"
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#include "coap_io.h"
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#include "block.h"
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/**
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* @defgroup observe Resource observation
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* API functions for interfacing with the observe handling (RFC7641)
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* @{
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*/
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/**
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* The value COAP_OBSERVE_ESTABLISH in a GET request indicates a new observe
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* relationship for (sender address, token) is requested.
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*/
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#define COAP_OBSERVE_ESTABLISH 0
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/**
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* The value COAP_OBSERVE_CANCEL in a GET request indicates that the observe
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* relationship for (sender address, token) must be cancelled.
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*/
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#define COAP_OBSERVE_CANCEL 1
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#ifndef COAP_OBS_MAX_NON
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/**
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* Number of notifications that may be sent non-confirmable before a confirmable
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* message is sent to detect if observers are alive. The maximum allowed value
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* here is @c 15.
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*/
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#define COAP_OBS_MAX_NON 5
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#endif /* COAP_OBS_MAX_NON */
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#ifndef COAP_OBS_MAX_FAIL
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/**
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* Number of confirmable notifications that may fail (i.e. time out without
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* being ACKed) before an observer is removed. The maximum value for
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* COAP_OBS_MAX_FAIL is @c 3.
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*/
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#define COAP_OBS_MAX_FAIL 3
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#endif /* COAP_OBS_MAX_FAIL */
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/** Subscriber information */
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typedef struct coap_subscription_t {
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struct coap_subscription_t *next; /**< next element in linked list */
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coap_session_t *session; /**< subscriber session */
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unsigned int non_cnt:4; /**< up to 15 non-confirmable notifies allowed */
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unsigned int fail_cnt:2; /**< up to 3 confirmable notifies can fail */
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unsigned int dirty:1; /**< set if the notification temporarily could not be
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* sent (in that case, the resource's partially
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* dirty flag is set too) */
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unsigned int has_block2:1; /**< GET request had Block2 definition */
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uint16_t tid; /**< transaction id, if any, in regular host byte order */
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coap_block_t block2; /**< GET request Block2 definition */
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size_t token_length; /**< actual length of token */
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unsigned char token[8]; /**< token used for subscription */
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coap_string_t *query; /**< query string used for subscription, if any */
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} coap_subscription_t;
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void coap_subscription_init(coap_subscription_t *);
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/** @} */
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#endif /* COAP_SUBSCRIBE_H_ */
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