added memrnd() (#685)

include/n2n.h

@@ -211,6 +211,7 @@ void hexdump (const uint8_t * buf, size_t len);
 void print_n2n_version ();
 int is_empty_ip_address (const n2n_sock_t * sock);
 void print_edge_stats (const n2n_edge_t *eee);
+int memrnd (uint8_t *address, size_t len);
 
 /* Sockets */
 char* sock_to_cstr (n2n_sock_str_t out,

src/edge_utils.c

@@ -367,9 +367,7 @@ n2n_edge_t* edge_init (const n2n_edge_conf_t *conf, int *rv) {
 
     // setup authenitcation scheme
     eee->conf.auth.scheme = n2n_auth_simple_id;
-    for(idx = 0; idx < N2N_AUTH_TOKEN_SIZE; ++idx) {
-        eee->conf.auth.token[idx] = n2n_rand() % 0xff;
-    }
+    memrnd(eee->conf.auth.token, N2N_AUTH_TOKEN_SIZE);
     eee->conf.auth.toksize = sizeof(eee->conf.auth.token);
 
     // first time calling edge_init_sockets needs -1 in the sockets for it does throw an error
@@ -1059,9 +1057,7 @@ void send_register_super (n2n_edge_t *eee) {
     cmn.flags = 0;
     memcpy(cmn.community, eee->conf.community_name, N2N_COMMUNITY_SIZE);
 
-    for(idx = 0; idx < N2N_COOKIE_SIZE; ++idx) {
-        eee->curr_sn->last_cookie[idx] = n2n_rand() % 0xff;
-    }
+    memrnd(eee->curr_sn->last_cookie, N2N_COOKIE_SIZE);
 
     memcpy(reg.cookie, eee->curr_sn->last_cookie, N2N_COOKIE_SIZE);
     reg.dev_addr.net_addr = ntohl(eee->device.ip_addr);

src/n2n.c

@@ -610,6 +610,24 @@ int sock_equal (const n2n_sock_t * a,
 
 /* *********************************************** */
 
+// fills a specified memory area with random numbers
+int memrnd (uint8_t *address, size_t len) {
+
+    for(; len >= 8; len -= 8) {
+        *(uint64_t*)address = n2n_rand();
+        address += 8;
+    }
+
+    for(; len > 0; len--) {
+        *address = n2n_rand();
+        address++;
+    }
+
+    return 0;
+}
+
+/* *********************************************** */
+
 #if defined(WIN32)
 int gettimeofday (struct timeval *tp, void *tzp) {
 

src/sn_utils.c

@@ -405,15 +405,11 @@ int sn_init(n2n_sn_t *sss) {
 
     /* Random auth token */
     sss->auth.scheme = n2n_auth_simple_id;
-    for(idx = 0; idx < N2N_AUTH_TOKEN_SIZE; ++idx) {
-        sss->auth.token[idx] = n2n_rand() % 0xff;
-    }
+    memrnd(sss->auth.token, N2N_AUTH_TOKEN_SIZE);
     sss->auth.toksize = sizeof(sss->auth.token);
 
     /* Random MAC address */
-    for(i = 0; i < 6; i++) {
-        sss->mac_addr[i] = n2n_rand();
-    }
+    memrnd(sss->mac_addr, N2N_MAC_SIZE);
     sss->mac_addr[0] &= ~0x01; /* Clear multicast bit */
     sss->mac_addr[0] |= 0x02;    /* Set locally-assigned bit */
 
@@ -890,12 +886,10 @@ static int re_register_and_purge_supernodes (n2n_sn_t *sss, struct sn_community
             cmn.flags = N2N_FLAGS_FROM_SUPERNODE;
             memcpy(cmn.community, comm->community, N2N_COMMUNITY_SIZE);
 
-            for(idx = 0; idx < N2N_COOKIE_SIZE; ++idx) {
-                cookie[idx] = n2n_rand() % 0xff;
-            }
-
+            memrnd(cookie, N2N_COOKIE_SIZE);
             memcpy(reg.cookie, cookie, N2N_COOKIE_SIZE);
             memcpy(peer->last_cookie, cookie, N2N_COOKIE_SIZE);
+
             reg.dev_addr.net_addr = ntohl(peer->dev_addr.net_addr);
             reg.dev_addr.net_bitlen = mask2bitlen(ntohl(peer->dev_addr.net_bitlen));
             get_local_auth(sss, &(reg.auth));

src/tuntap_linux.c

@@ -150,8 +150,7 @@ int tuntap_open (tuntap_dev *device,
         // also after the TAP interface UP status has been notified
         int i;
 
-        for(i = 0; i < 6; i++)
-            device->mac_addr[i] = n2n_rand();
+        memrnd(device->mac_addr, N2N_MAC_SIZE);
 
         // clear multicast bit
         device->mac_addr[0] &= ~0x01;