coap_delete_pdu: Add in multi-threaded lock protection

The reference counter needs to be protected.

include/coap3/coap_pdu.h

@@ -400,14 +400,19 @@ COAP_API coap_pdu_t *coap_new_pdu(coap_pdu_type_t type, coap_pdu_code_t code,
                                   coap_session_t *session);
 
 /**
- * Dispose of an CoAP PDU and frees associated storage.
- * Not that in general you should not call this function directly.
+ * Dispose of an CoAP PDU and free off associated storage.
+ *
+ * Note: In general you should not call this function directly.
  * When a PDU is sent with coap_send(), coap_delete_pdu() will be called
- * automatically for you.
+ * automatically for you. This is not for the case for coap_send_recv()
+ * where the sending and receiving PDUs need to be explicitly deleted.
+ *
+ * Note: If called with a reference count > 0, the reference count is
+ * decremented and the PDU still exists.
  *
  * @param pdu The PDU for free off.
  */
-void coap_delete_pdu(coap_pdu_t *pdu);
+COAP_API void coap_delete_pdu(coap_pdu_t *pdu);
 
 /**
  * Duplicate an existing PDU. Specific options can be ignored and not copied

include/coap3/coap_pdu_internal.h

@@ -374,6 +374,23 @@ int coap_option_check_repeatable(coap_option_num_t number);
 coap_pdu_t *coap_new_pdu_lkd(coap_pdu_type_t type, coap_pdu_code_t code,
                              coap_session_t *session);
 
+/**
+ * Dispose of an CoAP PDU and free off associated storage.
+ *
+ * Note: This function must be called in the locked state.
+ *
+ * Note: In general you should not call this function directly.
+ * When a PDU is sent with coap_send(), coap_delete_pdu() will be called
+ * automatically for you. This is not for the case for coap_send_recv()
+ * where the sending and receiving PDUs need to be explicitly deleted.
+ *
+ * Note: If called with a reference count > 0, the reference count is
+ * decremented and the PDU still exists.
+ *
+ * @param pdu The PDU for free off.
+ */
+void coap_delete_pdu_lkd(coap_pdu_t *pdu);
+
 /**
  * Duplicate an existing PDU. Specific options can be ignored and not copied
  * across.  The PDU data payload is not copied across.

include/coap3/coap_threadsafe_internal.h

@@ -319,7 +319,6 @@ int coap_lock_lock_func(void);
  * @param c Context.
  */
 #define coap_lock_unlock(c) do { \
-    assert(c); \
     coap_lock_unlock_func(); \
   } while (0)
 

src/coap_async.c

@@ -186,7 +186,7 @@ coap_free_async_sub(coap_context_t *context, coap_async_t *s) {
       coap_session_release_lkd(s->session);
     }
     if (s->pdu) {
-      coap_delete_pdu(s->pdu);
+      coap_delete_pdu_lkd(s->pdu);
       s->pdu = NULL;
     }
     coap_free_type(COAP_STRING, s);

src/coap_block.c

@@ -1930,7 +1930,7 @@ coap_send_q_blocks(coap_session_t *session,
   if (send_pdu == COAP_SEND_INC_PDU &&
       (mid = coap_send_internal(session, pdu)) == COAP_INVALID_MID) {
     /* Not expected, underlying issue somewhere */
-    coap_delete_pdu(block_pdu);
+    coap_delete_pdu_lkd(block_pdu);
     return COAP_INVALID_MID;
   }
 
@@ -1973,8 +1973,8 @@ coap_send_q_blocks(coap_session_t *session,
                                                  block.szx),
                             buf)) {
       coap_log_warn("Internal update issue option\n");
-      coap_delete_pdu(block_pdu);
-      coap_delete_pdu(t_pdu);
+      coap_delete_pdu_lkd(block_pdu);
+      coap_delete_pdu_lkd(t_pdu);
       break;
     }
 
@@ -1984,8 +1984,8 @@ coap_send_q_blocks(coap_session_t *session,
                         block.num,
                         block.szx)) {
       coap_log_warn("Internal update issue data\n");
-      coap_delete_pdu(block_pdu);
-      coap_delete_pdu(t_pdu);
+      coap_delete_pdu_lkd(block_pdu);
+      coap_delete_pdu_lkd(t_pdu);
       break;
     }
     if (COAP_PDU_IS_RESPONSE(block_pdu)) {
@@ -1994,7 +1994,7 @@ coap_send_q_blocks(coap_session_t *session,
     mid = coap_send_internal(session, block_pdu);
     if (mid == COAP_INVALID_MID) {
       /* Not expected, underlying issue somewhere */
-      coap_delete_pdu(t_pdu);
+      coap_delete_pdu_lkd(t_pdu);
       return COAP_INVALID_MID;
     }
     block_pdu = t_pdu;

src/coap_cache.c

@@ -195,7 +195,7 @@ coap_new_cache_entry_lkd(coap_session_t *session, const coap_pdu_t *pdu,
     entry->pdu = coap_pdu_init(pdu->type, pdu->code, pdu->mid, pdu->alloc_size);
     if (entry->pdu) {
       if (!coap_pdu_resize(entry->pdu, pdu->alloc_size)) {
-        coap_delete_pdu(entry->pdu);
+        coap_delete_pdu_lkd(entry->pdu);
         coap_free_type(COAP_CACHE_ENTRY, entry);
         return NULL;
       }
@@ -288,7 +288,7 @@ coap_delete_cache_entry(coap_context_t *ctx, coap_cache_entry_t *cache_entry) {
     HASH_DELETE(hh, ctx->cache, cache_entry);
   }
   if (cache_entry->pdu) {
-    coap_delete_pdu(cache_entry->pdu);
+    coap_delete_pdu_lkd(cache_entry->pdu);
   }
   coap_delete_cache_key(cache_entry->cache_key);
   if (cache_entry->callback && cache_entry->app_data) {

src/coap_io_lwip.c

@@ -209,7 +209,7 @@ coap_recvc(void *arg, struct udp_pcb *upcb, struct pbuf *p,
 #if NO_SYS == 0
   sys_sem_signal(&coap_io_timeout_sem);
 #endif /* NO_SYS == 0 */
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   return;
 
 error:
@@ -219,7 +219,7 @@ coap_recvc(void *arg, struct udp_pcb *upcb, struct pbuf *p,
    */
   if (session)
     coap_send_rst_lkd(session, pdu);
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   return;
 }
 #endif /* ! COAP_CLIENT_SUPPORT */
@@ -299,7 +299,7 @@ coap_udp_recvs(void *arg, struct udp_pcb *upcb, struct pbuf *p,
     coap_dispatch(ep->context, session, pdu);
   }
 
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   coap_free_packet(packet);
   coap_lock_unlock(ep->context);
 #if NO_SYS == 0
@@ -317,7 +317,7 @@ coap_udp_recvs(void *arg, struct udp_pcb *upcb, struct pbuf *p,
    */
   if (session && pdu)
     coap_send_rst_lkd(session, pdu);
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   coap_free_packet(packet);
   coap_lock_unlock(ep->context);
   return;

src/coap_net.c

@@ -228,7 +228,7 @@ coap_delete_node_lkd(coap_queue_t *node) {
   if (!node)
     return 0;
 
-  coap_delete_pdu(node->pdu);
+  coap_delete_pdu_lkd(node->pdu);
   if (node->session) {
     /*
      * Need to remove out of context->sendqueue as added in by coap_wait_ack()
@@ -1203,7 +1203,7 @@ coap_send_test_extended_token(coap_session_t *session) {
 
   token = coap_new_binary(session->max_token_size);
   if (token == NULL) {
-    coap_delete_pdu(pdu);
+    coap_delete_pdu_lkd(pdu);
     return COAP_INVALID_MID;
   }
   for (i = 0; i < session->max_token_size; i++) {
@@ -1495,7 +1495,7 @@ coap_send_lkd(coap_session_t *session, coap_pdu_t *pdu) {
       ret = coap_cancel_observe_lkd(session, &tmp, pdu->type);
       if (ret == 1) {
         /* Observe Cancel successfully sent */
-        coap_delete_pdu(pdu);
+        coap_delete_pdu_lkd(pdu);
         return ret;
       }
       /* Some mismatch somewhere - continue to send original packet */
@@ -1671,7 +1671,7 @@ coap_send_lkd(coap_session_t *session, coap_pdu_t *pdu) {
   return mid;
 
 error:
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   return COAP_INVALID_MID;
 }
 
@@ -1725,13 +1725,13 @@ coap_send_internal(coap_session_t *session, coap_pdu_t *pdu) {
         if (hop_limit == 1) {
           coap_log_warn("Proxy loop detected '%s'\n",
                         (char *)pdu->data);
-          coap_delete_pdu(pdu);
+          coap_delete_pdu_lkd(pdu);
           return (coap_mid_t)COAP_DROPPED_RESPONSE;
         } else if (hop_limit < 1 || hop_limit > 255) {
           /* Something is bad - need to drop this pdu (TODO or delete option) */
           coap_log_warn("Proxy return has bad hop limit count '%zu'\n",
                         hop_limit);
-          coap_delete_pdu(pdu);
+          coap_delete_pdu_lkd(pdu);
           return (coap_mid_t)COAP_DROPPED_RESPONSE;
         }
         hop_limit--;
@@ -1761,7 +1761,7 @@ coap_send_internal(coap_session_t *session, coap_pdu_t *pdu) {
              a_match[len] == ' ')) {
           coap_log_warn("Proxy loop detected '%s'\n",
                         (char *)pdu->data);
-          coap_delete_pdu(pdu);
+          coap_delete_pdu_lkd(pdu);
           return (coap_mid_t)COAP_DROPPED_RESPONSE;
         }
       }
@@ -1856,7 +1856,7 @@ coap_send_internal(coap_session_t *session, coap_pdu_t *pdu) {
       goto error;
     }
     bytes_written = coap_send_pdu(session, osc_pdu, NULL);
-    coap_delete_pdu(pdu);
+    coap_delete_pdu_lkd(pdu);
     pdu = osc_pdu;
   } else
 #endif /* COAP_OSCORE_SUPPORT */
@@ -1886,7 +1886,7 @@ coap_send_internal(coap_session_t *session, coap_pdu_t *pdu) {
   if (pdu->type != COAP_MESSAGE_CON
       || COAP_PROTO_RELIABLE(session->proto)) {
     coap_mid_t id = pdu->mid;
-    coap_delete_pdu(pdu);
+    coap_delete_pdu_lkd(pdu);
     return id;
   }
 
@@ -1903,7 +1903,7 @@ coap_send_internal(coap_session_t *session, coap_pdu_t *pdu) {
   node->timeout = coap_calc_timeout(session, r);
   return coap_wait_ack(session->context, session, node);
 error:
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   return COAP_INVALID_MID;
 }
 
@@ -2033,7 +2033,7 @@ coap_send_recv_lkd(coap_session_t *session, coap_pdu_t *request_pdu,
   session->doing_send_recv = 0;
   if (session->resp_pdu && session->resp_pdu->ref)
     session->resp_pdu->ref--;
-  coap_delete_pdu(session->resp_pdu);
+  coap_delete_pdu_lkd(session->resp_pdu);
   session->resp_pdu = NULL;
   coap_delete_bin_const(session->req_token);
   session->req_token = NULL;
@@ -2278,12 +2278,12 @@ coap_read_session(coap_context_t *ctx, coap_session_t *session, coap_tick_t now)
       if (!coap_pdu_parse(session->proto, packet->payload, bytes_read, pdu)) {
         coap_handle_event_lkd(session->context, COAP_EVENT_BAD_PACKET, session);
         coap_log_warn("discard malformed PDU\n");
-        coap_delete_pdu(pdu);
+        coap_delete_pdu_lkd(pdu);
         return;
       }
 
       coap_dispatch(ctx, session, pdu);
-      coap_delete_pdu(pdu);
+      coap_delete_pdu_lkd(pdu);
       return;
     }
   } else {
@@ -2315,7 +2315,7 @@ coap_read_session(coap_context_t *ctx, coap_session_t *session, coap_tick_t now)
                 && coap_pdu_parse_opt(session->partial_pdu)) {
               coap_dispatch(ctx, session, session->partial_pdu);
             }
-            coap_delete_pdu(session->partial_pdu);
+            coap_delete_pdu_lkd(session->partial_pdu);
             session->partial_pdu = NULL;
             session->partial_read = 0;
           } else {
@@ -2362,7 +2362,7 @@ coap_read_session(coap_context_t *ctx, coap_session_t *session, coap_tick_t now)
               if (coap_pdu_parse_header(session->partial_pdu, session->proto)) {
                 coap_dispatch(ctx, session, session->partial_pdu);
               }
-              coap_delete_pdu(session->partial_pdu);
+              coap_delete_pdu_lkd(session->partial_pdu);
               session->partial_pdu = NULL;
               session->partial_read = 0;
             }
@@ -2661,7 +2661,7 @@ coap_handle_dgram(coap_context_t *ctx, coap_session_t *session,
   }
 
   coap_dispatch(ctx, session, pdu);
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   return 0;
 
 error:
@@ -2670,7 +2670,7 @@ coap_handle_dgram(coap_context_t *ctx, coap_session_t *session,
    * https://rfc-editor.org/rfc/rfc7252#section-4.3 MAY send RST
    */
   coap_send_rst_lkd(session, pdu);
-  coap_delete_pdu(pdu);
+  coap_delete_pdu_lkd(pdu);
   return -1;
 }
 
@@ -2878,7 +2878,7 @@ coap_new_error_response(const coap_pdu_t *request, coap_pdu_code_t code,
     if (!coap_add_token(response, request->actual_token.length,
                         request->actual_token.s)) {
       coap_log_debug("cannot add token to error response\n");
-      coap_delete_pdu(response);
+      coap_delete_pdu_lkd(response);
       return NULL;
     }
 
@@ -3754,7 +3754,7 @@ handle_request(coap_context_t *context, coap_session_t *session, coap_pdu_t *pdu
                    response->mid);
     coap_show_pdu(COAP_LOG_DEBUG, response);
 drop_it_no_debug:
-    coap_delete_pdu(response);
+    coap_delete_pdu_lkd(response);
   }
   if (query)
     coap_delete_string(query);
@@ -3781,7 +3781,7 @@ handle_request(coap_context_t *context, coap_session_t *session, coap_pdu_t *pdu
   return;
 
 fail_response:
-  coap_delete_pdu(response);
+  coap_delete_pdu_lkd(response);
   response =
       coap_new_error_response(pdu, COAP_RESPONSE_CODE(resp),
                               &opt_filter);
@@ -4414,7 +4414,7 @@ coap_dispatch(coap_context_t *context, coap_session_t *session,
   }
   coap_delete_node_lkd(sent);
 #if COAP_OSCORE_SUPPORT
-  coap_delete_pdu(dec_pdu);
+  coap_delete_pdu_lkd(dec_pdu);
 #endif /* COAP_OSCORE_SUPPORT */
 }