From eea0c9b46ba69a9343c415af53644ea0a224f394 Mon Sep 17 00:00:00 2001
From: emanuele-f <black.silver@hotmail.it>
Date: Mon, 15 Jul 2019 23:33:11 +0200
Subject: [PATCH] Add option to disable p2p

---
 edge.c       |  9 ++++++++-
 edge_utils.c | 13 ++++++++++++-
 n2n.h        |  1 +
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/edge.c b/edge.c
index 49559ce..14b70bc 100644
--- a/edge.c
+++ b/edge.c
@@ -167,6 +167,7 @@ static void help() {
   printf("-A                       | Use AES CBC for encryption (default=use twofish).\n");
 #endif
   printf("-E                       | Accept multicast MAC addresses (default=drop).\n");
+  printf("-S                       | Do not connect P2P. Always use the supernode.\n");
   printf("-v                       | Make more verbose. Repeat as required.\n");
   printf("-t <port>                | Management UDP Port (for multiple edges on a machine).\n");
 
@@ -321,6 +322,12 @@ static int setOption(int optkey, char *optargument, n2n_priv_config_t *ec, n2n_e
       break;
     }
 
+  case 'S':
+    {
+      conf->allow_p2p = 0;
+      break;
+    }
+
   case 'h': /* help */
     {
       help();
@@ -361,7 +368,7 @@ static int loadFromCLI(int argc, char *argv[], n2n_edge_conf_t *conf, n2n_priv_c
   u_char c;
 
   while((c = getopt_long(argc, argv,
-			 "K:k:a:bc:Eu:g:m:M:s:d:l:p:fvhrt:i:"
+			 "K:k:a:bc:Eu:g:m:M:s:d:l:p:fvhrt:i:S"
 #ifdef N2N_HAVE_AES
 			 "A"
 #endif
diff --git a/edge_utils.c b/edge_utils.c
index 19c315e..598244a 100644
--- a/edge_utils.c
+++ b/edge_utils.c
@@ -332,7 +332,7 @@ static void supernode2addr(n2n_sock_t * sn, const n2n_sn_name_t addrIn) {
  */
 static void register_with_local_peers(n2n_edge_t * eee) {
 #ifndef SKIP_MULTICAST_PEERS_DISCOVERY
-  if(eee->multicast_joined) {
+  if(eee->multicast_joined && eee->conf.allow_p2p) {
     /* send registration to the local multicast group */
     traceEvent(TRACE_DEBUG, "Registering with multicast group %s:%u",
         N2N_MULTICAST_GROUP, N2N_MULTICAST_PORT);
@@ -677,6 +677,11 @@ static void send_register(n2n_edge_t * eee,
   n2n_REGISTER_t reg;
   n2n_sock_str_t sockbuf;
 
+  if(!eee->conf.allow_p2p) {
+    traceEvent(TRACE_DEBUG, "Skipping register as P2P is disabled");
+    return;
+  }
+
   memset(&cmn, 0, sizeof(cmn));
   memset(&reg, 0, sizeof(reg));
   cmn.ttl=N2N_DEFAULT_TTL;
@@ -717,6 +722,11 @@ static void send_register_ack(n2n_edge_t * eee,
   n2n_REGISTER_ACK_t ack;
   n2n_sock_str_t sockbuf;
 
+  if(!eee->conf.allow_p2p) {
+    traceEvent(TRACE_DEBUG, "Skipping register ACK as P2P is disabled");
+    return;
+  }
+
   memset(&cmn, 0, sizeof(cmn));
   memset(&ack, 0, sizeof(reg));
   cmn.ttl=N2N_DEFAULT_TTL;
@@ -1839,6 +1849,7 @@ void edge_init_conf_defaults(n2n_edge_conf_t *conf) {
   conf->mgmt_port = N2N_EDGE_MGMT_PORT; /* 5644 by default */
   conf->transop_id = N2N_TRANSFORM_ID_NULL;
   conf->drop_multicast = 1;
+  conf->allow_p2p = 1;
   conf->register_interval = REGISTER_SUPER_INTERVAL_DFL;
 
   if(getenv("N2N_KEY")) {
diff --git a/n2n.h b/n2n.h
index cb9f4d6..4bcee3b 100644
--- a/n2n.h
+++ b/n2n.h
@@ -209,6 +209,7 @@ typedef struct n2n_edge_conf {
   uint8_t             dyn_ip_mode;            /**< Interface IP address is dynamically allocated, eg. DHCP. */
   uint8_t             allow_routing;          /**< Accept packet no to interface address. */
   uint8_t             drop_multicast;         /**< Multicast ethernet addresses. */
+  uint8_t             allow_p2p;              /**< Allow P2P connection */
   uint8_t             sn_num;                 /**< Number of supernode addresses defined. */
   char                *encrypt_key;
   int                 register_interval;      /**< Interval for supernode registration, also used for UDP NAT hole punching. */