daemon/network: Avoid binding multiple transport protocols to one addr and port combination

Author: Frantisek Tobias

daemon/network.c

@@ -466,10 +466,7 @@ static int open_endpoint(const char *addr_str,
 	return kr_error(ret);
 }
 
-/** @internal Fetch a pointer to endpoint of given parameters (or NULL).
- * Beware that there might be multiple matches, though that's not common.
- * The matching isn't really precise in the sense that it might not find
- * and endpoint that would *collide* the passed one. */
+/** Fetch a pointer to endpoint of given parameters or a colliding one (or NULL). */
 static struct endpoint * endpoint_get(const char *addr_str,
                                       const struct sockaddr *sa,
                                       endpoint_flags_t flags)
@@ -483,12 +480,23 @@ static struct endpoint * endpoint_get(const char *addr_str,
 		return NULL;
 	endpoint_array_t *ep_array = *val;
 
-	uint16_t port = kr_inaddr_port(sa);
 	for (int i = 0; i < ep_array->len; ++i) {
 		struct endpoint *ep = &ep_array->at[i];
-		if ((flags.xdp || ep->port == port) && endpoint_flags_eq(ep->flags, flags)) {
+		if (flags.xdp) {
+			/* `key` matched by interface name */
+			kr_assert(ep_array->len == 1);
 			return ep;
 		}
+		if (kr_straddr_family(addr_str) == AF_UNIX) {
+			/* `key` matched by path */
+			kr_assert(ep_array->len == 1);
+			return ep;
+		}
+		/* else `key` already matched IP address + port,
+		 * so the only remaining distinction is UDP vs. TCP */
+		kr_assert(ep_array->len <= 2);
+		if (ep->flags.sock_type == flags.sock_type)
+			return ep;
 	}
 	return NULL;
 }

daemon/network.h

@@ -32,16 +32,6 @@ typedef struct {
 
 struct endpoint_key;
 
-static inline bool endpoint_flags_eq(endpoint_flags_t f1, endpoint_flags_t f2)
-{
-	if (f1.sock_type != f2.sock_type)
-		return false;
-	if (f1.kind && f2.kind)
-		return strcasecmp(f1.kind, f2.kind);
-	else
-		return f1.tls == f2.tls && f1.kind == f2.kind;
-}
-
 /** Wrapper for a single socket to listen on.
  * There are two types: normal have handle, special have flags.kind (and never both).
  *
@@ -142,7 +132,7 @@ void network_unregister(void);
 void network_deinit(void);
 
 /** Start listening on addr#port with flags.
- * \note if we did listen on that combination already,
+ * \note if we did listen on a colliding combination already,
  *       nothing is done and kr_error(EADDRINUSE) is returned.
  * \note there's no short-hand to listen both on UDP and TCP.
  * \note ownership of flags.* is taken on success.  TODO: non-success?