nits

Author: pavel-kirienko

libudpard/udpard.c

@@ -66,11 +66,6 @@ typedef unsigned char byte_t; ///< For compatibility with platforms where byte s
 #define IPv4_MCAST_PREFIX      0xEF000000UL
 #define IPv4_MCAST_SUFFIX_MASK 0x007FFFFFUL
 
-static udpard_udpip_ep_t make_topic_ep(const uint32_t subject_id)
-{
-    return (udpard_udpip_ep_t){ .ip = IPv4_MCAST_PREFIX | (subject_id & IPv4_MCAST_SUFFIX_MASK), .port = UDP_PORT };
-}
-
 static size_t      smaller(const size_t a, const size_t b) { return (a < b) ? a : b; }
 static size_t      larger(const size_t a, const size_t b) { return (a > b) ? a : b; }
 static int64_t     min_i64(const int64_t a, const int64_t b) { return (a < b) ? a : b; }
@@ -121,6 +116,11 @@ static int32_t cavl_compare_fragment_end(const void* const user, const udpard_tr
     return 0; // clang-format on
 }
 
+udpard_udpip_ep_t udpard_make_subject_endpoint(const uint32_t subject_id)
+{
+    return (udpard_udpip_ep_t){ .ip = IPv4_MCAST_PREFIX | (subject_id & IPv4_MCAST_SUFFIX_MASK), .port = UDP_PORT };
+}
+
 // NOLINTNEXTLINE(misc-no-recursion)
 void udpard_fragment_free_all(udpard_fragment_t* const frag, const udpard_mem_resource_t fragment_memory_resource)
 {
@@ -612,17 +612,17 @@ uint32_t udpard_tx_publish(udpard_tx_t* const   self,
             .sender_uid            = self->local_uid,
             .topic_hash            = topic_hash,
         };
-        out = tx_push(self, deadline, meta, make_topic_ep(subject_id), payload, user_transfer_reference);
+        out = tx_push(self, deadline, meta, udpard_make_subject_endpoint(subject_id), payload, user_transfer_reference);
     }
     return out;
 }
 
 uint32_t udpard_tx_p2p(udpard_tx_t* const      self,
                        const udpard_us_t       now,
                        const udpard_us_t       deadline,
+                       const udpard_prio_t     priority,
                        const uint64_t          remote_uid,
                        const udpard_udpip_ep_t remote_ep,
-                       const udpard_prio_t     priority,
                        const uint64_t          transfer_id,
                        const udpard_bytes_t    payload,
                        const bool              ack_required,

libudpard/udpard.h

@@ -197,6 +197,11 @@ typedef struct udpard_remote_t
     udpard_udpip_ep_t endpoints[UDPARD_NETWORK_INTERFACE_COUNT_MAX]; ///< Zeros in unavailable ifaces.
 } udpard_remote_t;
 
+/// Returns the destination multicast UDP/IP endpoint for the given subject ID.
+/// The application may use this function when setting up subscription sockets.
+/// If the subject-ID exceeds the allowed range, the excessive bits are masked out.
+udpard_udpip_ep_t udpard_make_subject_endpoint(const uint32_t subject_id);
+
 /// The semantics are similar to malloc/free.
 /// Consider using O1Heap: https://github.com/pavel-kirienko/o1heap. Alternatively, some applications may prefer to
 /// use a set of fixed-size block pool allocators (see the high-level overview for details); for example:
@@ -456,12 +461,13 @@ uint32_t udpard_tx_publish(udpard_tx_t* const   self,
 /// Similar to udpard_tx_publish, but for P2P transfers between specific nodes.
 /// This can only be sent in a response to a published message; the RX pipeline will provide the discovered return
 /// endpoint for this particular remote node.
+/// The destination UID may seem redundant but it is needed to filter out incorrectly addressed transfers.
 uint32_t udpard_tx_p2p(udpard_tx_t* const      self,
                        const udpard_us_t       now,
                        const udpard_us_t       deadline,
+                       const udpard_prio_t     priority,
                        const uint64_t          remote_uid,
                        const udpard_udpip_ep_t remote_ep,
-                       const udpard_prio_t     priority,
                        const uint64_t          transfer_id,
                        const udpard_bytes_t    payload,
                        const bool              ack_required,

tests/src/test_intrusive_tx.c

@@ -671,7 +671,7 @@ static void test_tx_publish(void)
     TEST_ASSERT_EQUAL(2000000, frame->deadline);
     TEST_ASSERT_EQUAL(udpard_prio_nominal, frame->priority);
     // Verify the destination is the correct multicast endpoint
-    const udpard_udpip_ep_t expected_ep = make_topic_ep(123);
+    const udpard_udpip_ep_t expected_ep = udpard_make_subject_endpoint(123);
     TEST_ASSERT_EQUAL(expected_ep.ip, frame->destination.ip);
     TEST_ASSERT_EQUAL(expected_ep.port, frame->destination.port);
     udpard_tx_pop(&tx, frame);
@@ -692,9 +692,9 @@ static void test_tx_p2p(void)
     const uint32_t enqueued = udpard_tx_p2p(&tx,
                                             1000000,               // now
                                             2000000,               // deadline
+                                            udpard_prio_high,      // priority
                                             0xFEDCBA9876543210ULL, // remote_uid
                                             (udpard_udpip_ep_t){ .ip = 0xC0A80101, .port = 9999 },
-                                            udpard_prio_high,      // priority
                                             0x0BADC0DE0BADC0DEULL, // transfer_id
                                             (udpard_bytes_t){ .size = interstellar_war_size, .data = interstellar_war },
                                             true, // ack_required
@@ -800,9 +800,9 @@ static void test_tx_deadline_at_current_time(void)
     enqueued = udpard_tx_p2p(&tx,
                              2000000, // now
                              1999999, // deadline in the past
+                             udpard_prio_high,
                              0xFEDCBA9876543210ULL,
                              (udpard_udpip_ep_t){ .ip = 0xC0A80101, .port = 9999 },
-                             udpard_prio_high,
                              0x0BADC0DE0BADC0DEULL,
                              (udpard_bytes_t){ .size = test_payload_size, .data = test_payload },
                              false,
@@ -870,9 +870,9 @@ static void test_tx_invalid_params(void)
                       udpard_tx_p2p(&tx,
                                     1000000,
                                     2000000,
+                                    udpard_prio_high,
                                     0, // remote_uid cannot be 0
                                     (udpard_udpip_ep_t){ .ip = 0xC0A80101, .port = 9999 },
-                                    udpard_prio_high,
                                     0x0BADC0DE0BADC0DEULL,
                                     (udpard_bytes_t){ .size = 10, .data = "test" },
                                     false,
@@ -881,9 +881,9 @@ static void test_tx_invalid_params(void)
                       udpard_tx_p2p(&tx,
                                     1000000,
                                     2000000,
+                                    udpard_prio_high,
                                     0xFEDCBA9876543210ULL,
                                     (udpard_udpip_ep_t){ .ip = 0, .port = 9999 }, // ip cannot be 0
-                                    udpard_prio_high,
                                     0x0BADC0DE0BADC0DEULL,
                                     (udpard_bytes_t){ .size = 10, .data = "test" },
                                     false,