nanocoap: add support for no-response option

See https://datatracker.ietf.org/doc/rfc7967/
RIOT-OS · Sep 27, 2022 · 06aa577 · 06aa577
1 parent 2d67eaf
commit 06aa577
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diff --git a/sys/include/net/coap.h b/sys/include/net/coap.h
@@ -49,6 +49,11 @@ extern "C" {
 #define COAP_OPT_BLOCK1         (27)
 #define COAP_OPT_PROXY_URI      (35)
 #define COAP_OPT_PROXY_SCHEME   (39)
+/**
+ * @brief suppress CoAP response
+ * @see [RFC 7968](https://datatracker.ietf.org/doc/html/rfc7967)
+ */
+#define COAP_OPT_NO_RESPONSE    (258)
 /** @} */
 
 /**

diff --git a/sys/include/net/nanocoap.h b/sys/include/net/nanocoap.h
@@ -1745,6 +1745,7 @@ ssize_t coap_build_hdr(coap_hdr_t *hdr, unsigned type, uint8_t *token,
  * @param[in]   payload_len length of payload
  *
  * @returns     size of reply packet on success
+ * @returns     0 if no response should be sent due to a No-Response option in the request
  * @returns     <0 on error
  * @returns     -ENOSPC if @p rbuf too small
  */

diff --git a/sys/net/application_layer/nanocoap/nanocoap.c b/sys/net/application_layer/nanocoap/nanocoap.c
@@ -514,6 +514,16 @@ ssize_t coap_build_reply(coap_pkt_t *pkt, unsigned code,
         }
     }
 
+    uint32_t no_response;
+    if (coap_opt_get_uint(pkt, COAP_OPT_NO_RESPONSE, &no_response) == 0) {
+        uint8_t mask = 1 << (code >> 5);
+
+        /* option contains bitmap of disinterest */
+        if ((type == COAP_TYPE_NON) && (no_response & mask)) {
+            return 0;
+        }
+    }
+
     coap_build_hdr((coap_hdr_t *)rbuf, type, coap_get_token(pkt), tkl, code,
                    ntohs(pkt->hdr->id));
     coap_hdr_set_type((coap_hdr_t *)rbuf, type);