added payload struct to carry supernode data (#501)

* added payload struct to carry supernode data

* added payload struct to carry supernode data

* added payload struct to carry supernode data

Co-authored-by: Luca Deri <lucaderi@users.noreply.github.com>

include/n2n_define.h

@@ -32,11 +32,10 @@
 /* Max available space to add supernodes' informations (sockets and MACs) in REGISTER_SUPER_ACK
  * Field sizes of REGISTER_SUPER_ACK as used in encode/decode fucntions in src/wire.c
  * REVISIT: replace 255 by DEFAULT_MTU as soon as header encryption allows for longer packets to be encrypted. */
-#define REG_SUPER_ACK_PAYLOAD_SPACE \
-	(255-(1+1+2+sizeof(n2n_common_t)+sizeof(n2n_cookie_t)+sizeof(n2n_mac_t)+1+2+4+1+sizeof(n2n_sock_t)+1)) \
+#define REG_SUPER_ACK_PAYLOAD_SPACE   (255-(sizeof(n2n_common_t)+sizeof(n2n_REGISTER_SUPER_ACK_t)))
 
 /* Space needed to store socket and MAC address of a supernode */
-#define REG_SUPER_ACK_PAYLOAD_ENTRY_SIZE		(sizeof(n2n_sock_t)+sizeof(n2n_mac_t))
+#define REG_SUPER_ACK_PAYLOAD_ENTRY_SIZE		(sizeof(n2n_REGISTER_SUPER_ACK_payload_t))
 
 #define PURGE_REGISTRATION_FREQUENCY   30
 #define RE_REG_AND_PURGE_FREQUENCY     10

include/n2n_wire.h

@@ -34,6 +34,15 @@
 
 #include "sn_selection.h"
 
+
+/* REGISTER_SUPER_ACK may contain extra payload (their number given by num_sn)
+ * of following type describing a(nother) supernode */
+typedef struct n2n_REGISTER_SUPER_ACK_payload {
+  n2n_sock_t           sock;          /**< socket of supernode */
+  n2n_mac_t            mac;           /**< MAC of supernode */
+} n2n_REGISTER_SUPER_ACK_payload_t;
+
+
 int encode_uint8( uint8_t * base,
                   size_t * idx,
                   const uint8_t v );

src/edge_utils.c

@@ -1995,8 +1995,7 @@ void readFromIPSocket(n2n_edge_t * eee, int in_sock) {
 	char * ip_str = NULL;
 	n2n_REGISTER_SUPER_ACK_t ra;
 	uint8_t tmpbuf[REG_SUPER_ACK_PAYLOAD_SPACE];
-	n2n_sock_t *tmp_sock;
-	n2n_mac_t *tmp_mac;
+	n2n_REGISTER_SUPER_ACK_payload_t *payload;
 	int i;
 	int skip_add;
 	struct peer_info *sn;
@@ -2039,30 +2038,28 @@ void readFromIPSocket(n2n_edge_t * eee, int in_sock) {
 
 	    if(0 == memcmp(ra.cookie, eee->curr_sn->last_cookie, N2N_COOKIE_SIZE))
 	      {
-                tmp_sock = (void*)&tmpbuf;
-                tmp_mac = (void*)&tmpbuf[sizeof(n2n_sock_t)];
+		payload = (n2n_REGISTER_SUPER_ACK_payload_t*)tmpbuf;
 
                 for(i=0; i<ra.num_sn; i++){
                   skip_add = SN_ADD;
-                  sn = add_sn_to_list_by_mac_or_sock(&(eee->conf.supernodes), tmp_sock, tmp_mac, &skip_add);
+                  sn = add_sn_to_list_by_mac_or_sock(&(eee->conf.supernodes), &(payload->sock), &(payload->mac), &skip_add);
 
                   if(skip_add == SN_ADD_ADDED){
                     sn->ip_addr = calloc(1,N2N_EDGE_SN_HOST_SIZE);
                     if(sn->ip_addr != NULL){
-                      inet_ntop(tmp_sock->family,
-                                (tmp_sock->family == AF_INET)?(void*)&tmp_sock->addr.v4:(void*)&tmp_sock->addr.v6,
+                      inet_ntop(payload->sock.family,
+                                (payload->sock.family == AF_INET)?(void*)&(payload->sock.addr.v4):(void*)&(payload->sock.addr.v6),
                                 sn->ip_addr, N2N_EDGE_SN_HOST_SIZE-1);
-                      sprintf (sn->ip_addr, "%s:%u", sn->ip_addr, (uint16_t)tmp_sock->port);
-                      //sock_to_cstr(sn->ip_addr, tmp_sock);
+                      sprintf (sn->ip_addr, "%s:%u", sn->ip_addr, (uint16_t)(payload->sock.port));
+                      //sock_to_cstr(sn->ip_addr, payload->sock);
                     }
                     sn_selection_criterion_default(&(sn->selection_criterion));
                     sn->last_seen = now - LAST_SEEN_SN_NEW;
                     sn->last_valid_time_stamp = initial_time_stamp();
                     traceEvent(TRACE_NORMAL, "Supernode '%s' added to the list of supernodes.", sn->ip_addr);
                   }
-
-                  tmp_sock = (void*)tmp_sock + REG_SUPER_ACK_PAYLOAD_ENTRY_SIZE;
-                  tmp_mac = (void*)tmp_sock + sizeof(n2n_sock_t);
+                  // shfiting to the next payload entry
+                  payload++;
 		}
 
 		eee->last_sup = now;

src/sn_utils.c

@@ -1209,9 +1209,9 @@ static int process_udp(n2n_sn_t * sss,
                                                                             * their SN_ACTIVE time before they get re-registred to. */
 
 	  if(((++num)*REG_SUPER_ACK_PAYLOAD_ENTRY_SIZE) > REG_SUPER_ACK_PAYLOAD_SPACE) break; /* no more space available in REGISTER_SUPER_ACK payload */
-	  memcpy((void*)tmp_dst, (void*)&(peer->sock), sizeof(n2n_sock_t));
+	  memcpy(tmp_dst, &(peer->sock), sizeof(n2n_sock_t));
 	  tmp_dst += sizeof(n2n_sock_t);
-	  memcpy((void*)tmp_dst, (void*)&(peer->mac_addr), sizeof(n2n_mac_t));
+	  memcpy(tmp_dst, &(peer->mac_addr), sizeof(n2n_mac_t));
 	  tmp_dst += sizeof(n2n_mac_t);
 	}
 	ack.num_sn = num;
@@ -1255,8 +1255,7 @@ static int process_udp(n2n_sn_t * sss,
     macstr_t           	 	    mac_buf1;
     n2n_sock_t          	    sender;
     n2n_sock_t        		    *orig_sender;
-    n2n_sock_t			    *tmp_sock;
-    n2n_mac_t			    *tmp_mac;
+    n2n_REGISTER_SUPER_ACK_payload_t  *payload;
     int				    i;
     uint8_t			    dec_tmpbuf[REG_SUPER_ACK_PAYLOAD_SPACE];
     int                             skip_add;
@@ -1308,20 +1307,18 @@ static int process_udp(n2n_sn_t * sss,
       }
     }
 
-    tmp_sock = (n2n_sock_t *)dec_tmpbuf;
-    tmp_mac  = (n2n_mac_t *)(dec_tmpbuf + sizeof(n2n_sock_t));
+    payload = (n2n_REGISTER_SUPER_ACK_payload_t *)dec_tmpbuf;
 
     for(i=0; i<ack.num_sn; i++) {
       skip_add = SN_ADD;
-      tmp = add_sn_to_list_by_mac_or_sock(&(sss->federation->edges), tmp_sock, tmp_mac, &skip_add);
+      tmp = add_sn_to_list_by_mac_or_sock(&(sss->federation->edges), &(payload->sock), &(payload->mac), &skip_add);
 
       if(skip_add == SN_ADD_ADDED) {
         tmp->last_seen = now - LAST_SEEN_SN_NEW;
       }
 
-      /* REVISIT: find a more elegant expression to increase following pointers. */
-      tmp_sock = tmp_sock + REG_SUPER_ACK_PAYLOAD_ENTRY_SIZE;
-      tmp_mac  = (n2n_mac_t *)(tmp_sock + sizeof(n2n_sock_t));
+      // shift to next payload entry
+      payload++;
     }
 
     break;