Add rate limitations for challenges.

message.c

@@ -549,7 +549,7 @@ preparse_packet(const unsigned char *from, struct interface *ifp,
         if(neigh == NULL)
             return NULL;
         rc = send_challenge_request(neigh);
-        if(rc)
+        if(rc < -1)
             fputs("Could not send challenge request.\n", stderr);
         goto maybe_send_challenge_reply;
     }
@@ -1254,32 +1254,45 @@ int
 send_challenge_request(struct neighbour *neigh)
 {
     int rc;
+
+    gettime(&now);
+    if(timeval_compare(&now, &neigh->challenge_request_limitation) <= 0)
+        return -1;
+
     debugf("Sending challenge request to %s on %s.\n",
            format_address(neigh->address), neigh->ifp->name);
     rc = read_random_bytes(neigh->nonce, NONCE_LEN);
     if(rc < NONCE_LEN) {
         perror("read_random_bytes");
-        return -1;
+        return -2;
     }
     start_message(&neigh->buf, neigh->ifp, MESSAGE_CHALLENGE_REQUEST, NONCE_LEN);
     accumulate_bytes(&neigh->buf, neigh->nonce, NONCE_LEN);
     end_message(&neigh->buf, MESSAGE_CHALLENGE_REQUEST, NONCE_LEN);
     gettime(&now);
-    timeval_add_msec(&neigh->challenge_deadline, &now, 300);
+    timeval_add_msec(&neigh->challenge_deadline, &now, 30000);
+    timeval_add_msec(&neigh->challenge_request_limitation, &now, 300);
     schedule_flush_now(&neigh->buf);
     return 0;
 }
 
-void
+int
 send_challenge_reply(struct neighbour *neigh, const unsigned char *crypto_nonce,
                      int len)
 {
+    gettime(&now);
+    if(timeval_compare(&now, &neigh->challenge_reply_limitation) <= 0)
+        return -1;
+
     debugf("Sending challenge reply to %s on %s.\n",
            format_address(neigh->address), neigh->ifp->name);
     start_message(&neigh->buf, neigh->ifp, MESSAGE_CHALLENGE_REPLY, len);
     accumulate_bytes(&neigh->buf, crypto_nonce, len);
     end_message(&neigh->buf, MESSAGE_CHALLENGE_REPLY, len);
+    gettime(&now);
+    timeval_add_msec(&neigh->challenge_reply_limitation, &now, 300);
     schedule_flush_now(&neigh->buf);
+    return 0;
 }
 
 static void

message.h

@@ -64,8 +64,8 @@ int send_pc(struct buffered *buf, struct interface *ifp);
 void send_ack(struct neighbour *neigh, unsigned short nonce,
               unsigned short interval);
 int send_challenge_request(struct neighbour *neigh);
-void send_challenge_reply(struct neighbour *neigh,
-                          const unsigned char *crypto_nonce, int len);
+int send_challenge_reply(struct neighbour *neigh,
+                         const unsigned char *crypto_nonce, int len);
 void send_multicast_hello(struct interface *ifp, unsigned interval, int force);
 void send_unicast_hello(struct neighbour *neigh, unsigned interval, int force);
 void send_hello(struct interface *ifp);

neighbour.c

@@ -110,6 +110,8 @@ find_neighbour(const unsigned char *address, struct interface *ifp)
     neigh->rtt_time = zero;
     neigh->index_len = -1;
     neigh->challenge_deadline = zero;
+    neigh->challenge_request_limitation = zero;
+    neigh->challenge_reply_limitation = zero;
     neigh->ifp = ifp;
     neigh->buf.buf = buf;
     neigh->buf.size = ifp->buf.size;

neighbour.h

@@ -52,6 +52,8 @@ struct neighbour {
     unsigned char index[32];
     unsigned char nonce[NONCE_LEN];
     struct timeval challenge_deadline;
+    struct timeval challenge_request_limitation;
+    struct timeval challenge_reply_limitation;
     struct interface *ifp;
     struct buffered buf;
 };