working on todo.md features

deps/udpsclient/udps_client.c

@@ -48,7 +48,7 @@
 #define UDPS_FRAG_MASK_BYTES (UDPS_MAX_FRAGMENTS / 8)
 
 /** Largest datagram we can receive, header included. */
-#define UDPS_RX_BUF_BYTES (65535 + 17)
+#define UDPS_RX_BUF_BYTES UDPS_MAX_DATAGRAM_BYTES
 
 /** An incomplete reassembly older than this is abandoned. */
 #define UDPS_SLOT_STALE_S 2.0
@@ -209,6 +209,9 @@ struct udps_client {
     udps_stats_t stats;
     char         err[256];
 
+    udps_datagram_cb datagram_cb;   /**< NULL until set; fires inside poll(). */
+    void            *datagram_user;
+
     udps_config_cb on_config;
     udps_data_cb   on_data;
     udps_event_cb  on_event;
@@ -1245,6 +1248,15 @@ static void copy_str(char *dst, size_t cap, const char *src) {
     dst[cap - 1u] = '\0';
 }
 
+void udps_client_set_datagram_cb(udps_client_t *client,
+                                 udps_datagram_cb cb, void *user) {
+    if (client == NULL) {
+        return;
+    }
+    client->datagram_cb   = cb;
+    client->datagram_user = user;
+}
+
 udps_client_t *udps_client_create(const udps_client_config_t *cfg) {
     udps_client_t *c;
 
@@ -1468,6 +1480,11 @@ int udps_client_poll(udps_client_t *c, int timeout_ms) {
             }
             drained++;
             c->last_data = now_mono();
+            /* The raw datagram, before anything reads out of rxbuf: this is the
+             * only place a malformed or duplicate datagram is still visible. */
+            if (c->datagram_cb != NULL) {
+                c->datagram_cb(c->rxbuf, (size_t)n, now_wall(), c->datagram_user);
+            }
             if ((size_t)n >= UDPS_HEADER_SIZE) {
                 handle_packet(c, c->rxbuf, (size_t)n);
             }