Merge pull request #18047 from benpicco/nanocoap-state_cleanup

nanocoap_sock: clean up state management
RIOT-OS · May 18, 2022 · e676893 · e676893
2 parents 5fd88e1 + 7c75852
commit e676893
Showing 1 changed file with 13 additions and 15 deletions.
diff --git a/sys/net/application_layer/nanocoap/sock.c b/sys/net/application_layer/nanocoap/sock.c
@@ -38,8 +38,9 @@
 #include "debug.h"
 
 enum {
-    STATE_SEND_REQUEST,
-    STATE_AWAIT_RESPONSE,
+    STATE_REQUEST_SEND,     /**< request was just sent or will be sent again */
+    STATE_RESPONSE_RCVD,    /**< response received but might be invalid      */
+    STATE_RESPONSE_OK,      /**< valid response was received                 */
 };
 
 typedef struct {
@@ -125,7 +126,7 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
     void *payload, *ctx = NULL;
     const uint8_t *token = coap_get_token(pkt);
     uint8_t token_len = coap_get_token_len(pkt);
-    uint8_t state = STATE_SEND_REQUEST;
+    uint8_t state = STATE_REQUEST_SEND;
 
     /* random timeout, deadline for receive retries */
     uint32_t timeout = random_uint32_range(CONFIG_COAP_ACK_TIMEOUT_MS * US_PER_MS,
@@ -138,9 +139,7 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
     /* check if we expect a reply */
     const bool confirmable = coap_get_type(pkt) == COAP_TYPE_CON;
 
-    /* try receiving another packet without re-request */
-    bool retry_rx = false;
-
+    /* Create the first payload snip from the request buffer */
     iolist_t head = {
         .iol_next = pkt->snips,
         .iol_base = pkt->hdr,
@@ -149,7 +148,7 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
 
     while (1) {
         switch (state) {
-        case STATE_SEND_REQUEST:
+        case STATE_REQUEST_SEND:
             DEBUG("nanocoap: send %u bytes (%u tries left)\n",
                   (unsigned)iolist_size(&head), tries_left);
 
@@ -171,9 +170,9 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
 
             /* ctx must have been released at this point */
             assert(ctx == NULL);
-            state = STATE_AWAIT_RESPONSE;
             /* fall-through */
-        case STATE_AWAIT_RESPONSE:
+        case STATE_RESPONSE_RCVD:
+        case STATE_RESPONSE_OK:
             DEBUG("nanocoap: waiting for response (timeout: %"PRIu32" µs)\n",
                   _deadline_left_us(deadline));
             tmp = sock_udp_recv_buf(sock, &payload, &ctx, _deadline_left_us(deadline), NULL);
@@ -184,15 +183,14 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
              * releases the packet.
              * This assertion will trigger should the behavior change in the future.
              */
-            if (retry_rx) {
+            if (state != STATE_REQUEST_SEND) {
                 assert(tmp == 0 && ctx == NULL);
             }
             if (tmp == 0) {
                 /* no more data */
                 /* sock_udp_recv_buf() needs to be called in a loop until ctx is NULL again
                  * to release the buffer */
-                if (retry_rx) {
-                    retry_rx = false;
+                if (state == STATE_RESPONSE_RCVD) {
                     continue;
                 }
                 return res;
@@ -202,7 +200,7 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
                 DEBUG("nanocoap: timeout\n");
                 timeout *= 2;
                 deadline = _deadline_from_interval(timeout);
-                state = STATE_SEND_REQUEST;
+                state = STATE_REQUEST_SEND;
                 continue;
             }
             if (res < 0) {
@@ -211,17 +209,17 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
             }
 
             /* parse response */
+            state = STATE_RESPONSE_RCVD;
             if (coap_parse(pkt, payload, res) < 0) {
                 DEBUG("nanocoap: error parsing packet\n");
-                retry_rx = true;
                 continue;
             }
             else if (_id_or_token_missmatch(pkt, id, token, token_len)) {
                 DEBUG("nanocoap: ID mismatch %u != %u\n", coap_get_id(pkt), id);
-                retry_rx = true;
                 continue;
             }
 
+            state = STATE_RESPONSE_OK;
             DEBUG("nanocoap: response code=%i\n", coap_get_code(pkt));
             switch (coap_get_type(pkt)) {
             case COAP_TYPE_RST: