fixed endianess issue in federated sn socket forwarding (#1030)

include/n2n_typedefs.h

@@ -406,7 +406,9 @@ typedef struct n2n_REGISTER_SUPER_NAK {
 /* 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 */
+    // REVISIT: interim for bugfix (https://github.com/ntop/n2n/issues/1029)
+    //          remove with 4.0
+    uint8_t       sock[sizeof(uint16_t) + sizeof(uint16_t) + IPV6_SIZE]; /**< socket of supernode */
     n2n_mac_t     mac;                                                   /**< MAC of supernode */
 } n2n_REGISTER_SUPER_ACK_payload_t;
 

include/n2n_wire.h

@@ -118,6 +118,19 @@ int decode_sock (n2n_sock_t * sock,
                  size_t * rem,
                  size_t * idx);
 
+// bugfix for https://github.com/ntop/n2n/issues/1029
+// REVISIT: best to be removed with 4.0
+int encode_sock_payload (uint8_t * base,
+                         size_t * idx,
+                         const n2n_sock_t * sock);
+
+// bugfix for https://github.com/ntop/n2n/issues/1029
+// REVISIT: best to be removed with 4.0
+int decode_sock_payload (n2n_sock_t * sock,
+                         const uint8_t * base,
+                         size_t * rem,
+                         size_t * idx);
+
 int encode_REGISTER (uint8_t * base,
                      size_t * idx,
                      const n2n_common_t * common,

src/edge_utils.c

@@ -2414,6 +2414,7 @@ void process_udp (n2n_edge_t *eee, const struct sockaddr *sender_sock, const SOC
                 uint8_t tmpbuf[REG_SUPER_ACK_PAYLOAD_SPACE];
                 char ip_tmp[N2N_EDGE_SN_HOST_SIZE];
                 n2n_REGISTER_SUPER_ACK_payload_t *payload;
+                n2n_sock_t payload_sock;
                 int i;
                 int skip_add;
 
@@ -2474,15 +2475,22 @@ void process_udp (n2n_edge_t *eee, const struct sockaddr *sender_sock, const SOC
                 // from here on, 'sn' gets used differently
                 for(i = 0; i < ra.num_sn; i++) {
                     skip_add = SN_ADD;
-                    sn = add_sn_to_list_by_mac_or_sock(&(eee->conf.supernodes), &(payload->sock), payload->mac, &skip_add);
+
+                    // bugfix for https://github.com/ntop/n2n/issues/1029
+                    // REVISIT: best to be removed with 4.0
+                    idx = 0;
+                    rem = sizeof(payload->sock);
+                    decode_sock_payload(&payload_sock, payload->sock, &rem, &idx);
+
+                    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(payload->sock.family,
+                            inet_ntop(payload_sock.family,
-                                      (payload->sock.family == AF_INET) ? (void*)&(payload->sock.addr.v4) : (void*)&(payload->sock.addr.v6),
+                                      (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(ip_tmp, "%s:%u", (char*)sn->ip_addr, (uint16_t)(payload->sock.port));
+                            sprintf(ip_tmp, "%s:%u", (char*)sn->ip_addr, (uint16_t)(payload_sock.port));
                             memcpy(sn->ip_addr, ip_tmp, sizeof(ip_tmp));
                         }
                         sn_selection_criterion_default(&(sn->selection_criterion));

src/sn_utils.c

@@ -1990,7 +1990,12 @@ static int process_udp (n2n_sn_t * sss,
                                                                             * We need to allow for a little extra time because supernodes sometimes exceed
                                                                             * 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(&(payload->sock), &(peer->sock), sizeof(n2n_sock_t));
+
+                // bugfix for https://github.com/ntop/n2n/issues/1029
+                // REVISIT: best to be removed with 4.0 (replace with encode_sock)
+                idx = 0;
+                encode_sock_payload(payload->sock, &idx, &(peer->sock));
+
                 memcpy(payload->mac, peer->mac_addr, sizeof(n2n_mac_t));
                 // shift to next payload entry
                 payload++;
@@ -2182,6 +2187,7 @@ static int process_udp (n2n_sn_t * sss,
             int                              i;
             uint8_t                          dec_tmpbuf[REG_SUPER_ACK_PAYLOAD_SPACE];
             n2n_REGISTER_SUPER_ACK_payload_t *payload;
+            n2n_sock_t                       payload_sock;
 
             memset(&ack, 0, sizeof(n2n_REGISTER_SUPER_ACK_t));
 
@@ -2224,7 +2230,14 @@ static int process_udp (n2n_sn_t * sss,
                 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), &(payload->sock), payload->mac, &skip_add);
+
+                    // bugfix for https://github.com/ntop/n2n/issues/1029
+                    // REVISIT: best to be removed with 4.0
+                    idx = 0;
+                    rem = sizeof(payload->sock);
+                    decode_sock_payload(&payload_sock, payload->sock, &rem, &idx);
+
+                    tmp = add_sn_to_list_by_mac_or_sock(&(sss->federation->edges), &(payload_sock), payload->mac, &skip_add);
                     // other supernodes communicate via standard udp socket
                     tmp->socket_fd = sss->sock;
 

src/wire.c

@@ -305,6 +305,50 @@ int decode_sock (n2n_sock_t * sock,
 }
 
 
+// bugfix for https://github.com/ntop/n2n/issues/1029
+// REVISIT: best to be removed with 4.0
+int encode_sock_payload (uint8_t * base,
+                         size_t * idx,
+                         const n2n_sock_t * sock) {
+
+    int retval = 0;
+
+    retval += encode_uint8(base, idx, sock->family);
+    retval += encode_uint8(base, idx, 0); // blank
+    retval += encode_uint8(base, idx, sock->port & 0x00FF);
+    retval += encode_uint8(base, idx, sock->port >> 8);
+    // copy full address field length
+    retval += encode_buf(base, idx, sock->addr.v6, IPV6_SIZE);
+
+    return retval;
+}
+
+
+// bugfix for https://github.com/ntop/n2n/issues/1029
+// REVISIT: best to be removed with 4.0
+int decode_sock_payload (n2n_sock_t * sock,
+                         const uint8_t * base,
+                         size_t * rem,
+                         size_t * idx) {
+
+    int retval = 0;
+    uint8_t port_low = 0;
+    uint8_t port_high = 0;
+
+    retval += decode_uint8(&(sock->family), base, rem, idx);
+    ++(*idx); // skip blank
+    --(*rem);
+    ++retval;
+    retval += decode_uint8(&port_low, base, rem, idx);
+    retval += decode_uint8(&port_high, base, rem, idx);
+    sock->port = ((uint16_t)port_high << 8) + port_low;
+    // copy full address field length
+    retval += decode_buf(sock->addr.v6, IPV6_SIZE, base, rem, idx);
+
+    return retval;
+}
+
+
 int encode_REGISTER (uint8_t *base,
                      size_t *idx,
                      const n2n_common_t *common,