1COAP_KEEPALIVE(3) libcoap Manual COAP_KEEPALIVE(3)
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6 coap_keepalive, coap_context_set_keepalive - work with CoAP keepalive
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9 #include <coap2/coap.h>
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11 void void coap_context_set_keepalive(coap_context_t *context, unsigned
12 int seconds);
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14 Link with -lcoap-2, -lcoap-2-gnutls, -lcoap-2-openssl or
15 -lcoap-2-tinydtls depending on your (D)TLS library type.
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18 There may be a requirement to send out keepalive traffic when the CoAP
19 session is idle (no packets have been sent or received for a specified
20 period) to keep, say, an interim NAT device "warm" with the NAT
21 translation state, or to periodically check whether the device at the
22 other end of the session has "gone away".
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24 For DTLS, this is done with the confirmable CoAP (0.00) Ping packet,
25 which solicits a CoAP RST response. For TLS, this is done with Coap
26 (7.02) Ping packet, which solicits a CoAP (7.03) Pong response, all
27 handled by libcoap.
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29 The coap_context_set_keepalive() function needs to be called to update
30 the context with the keepalive for idle traffic timeout of seconds. If
31 seconds is set to 0, then the sending of keepalives is disabled. Any
32 sessions created from this context will use the same seconds value to
33 determine whether a keepalive "ping" is to be sent out or not.
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35 Applications can track the usage of the receipt of "pings" and receipt
36 of "responses" by defining the respective handlers to use by using
37 coap_register_ping_handler() and coap_register_pong_handler().
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39 If the keepalive fails to solicit a response, then this can be tracked
40 by defining the handler to use by using coap_register_nack_handler()
41 which will be called with a reason of COAP_NACK_TOO_MANY_RETRIES.
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43 Note
44 coap_context_set_keepalive() is supported by both the CoAP client
45 and CoAP server.
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48 coap_handler(3)
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51 "RFC7252: The Constrained Application Protocol (CoAP)"
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53 "RFC8323: CoAP (Constrained Application Protocol) over TCP, TLS, and
54 WebSockets"
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57 Please report bugs on the mailing list for libcoap:
58 libcoap-developers@lists.sourceforge.net
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61 The libcoap project <libcoap-developers@lists.sourceforge.net>
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65coap_keepalive 4.2.1 01/26/2021 COAP_KEEPALIVE(3)