Add kind field to struct resend.

resend.c

@@ -95,6 +95,7 @@ record_request(const unsigned char *prefix, unsigned char plen,
         request = malloc(sizeof(struct resend));
         if(request == NULL)
             return -1;
+        request->kind = RESEND_REQUEST;
         memcpy(request->prefix, prefix, 16);
         request->plen = plen;
         request->seqno = seqno;

resend.h

@@ -22,7 +22,11 @@ THE SOFTWARE.
 
 #define REQUEST_TIMEOUT 125000
 
+#define RESEND_REQUEST 1
+#define RESEND_UPDATE 2
+
 struct resend {
+    int kind;
     unsigned char prefix[16];
     unsigned char plen;
     unsigned short seqno;