From afd5acc4225111324e23f0927ab04282e5b80865 Mon Sep 17 00:00:00 2001
From: Hamish Coleman <hamish@zot.org>
Date: Sat, 19 Oct 2024 15:53:39 +1100
Subject: [PATCH] Check that the peer object is not too old to use

This is an attempt to fix the auth/reconnect issue.
---
 src/edge_utils.c |  6 ++----
 src/peer_info.c  | 24 ++++++++++++++++++++++++
 src/peer_info.h  |  1 +
 src/sn_utils.c   |  8 +++++++-
 4 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/src/edge_utils.c b/src/edge_utils.c
index 1aa6b7d..9be89b3 100644
--- a/src/edge_utils.c
+++ b/src/edge_utils.c
@@ -2726,12 +2726,10 @@ void process_udp (struct n3n_runtime_data *eee, const struct sockaddr *sender_so
 
             if((memcmp(nak.srcMac, eee->device.mac_addr, sizeof(n2n_mac_t))) == 0) {
                 macstr_t buf_src;
-                macstr_t buf_dev;
                 traceEvent(
                     TRACE_ERROR,
-                    "auth error: %s != %s",
-                    macaddr_str(buf_src, nak.srcMac),
-                    macaddr_str(buf_dev, eee->device.mac_addr)
+                    "auth error: mac %s",
+                    macaddr_str(buf_src, nak.srcMac)
                 );
                 if(eee->conf.shared_secret) {
                     traceEvent(TRACE_ERROR, "authentication error, username or password not recognized by supernode");
diff --git a/src/peer_info.c b/src/peer_info.c
index 43cc9f6..d5ca9e7 100644
--- a/src/peer_info.c
+++ b/src/peer_info.c
@@ -98,6 +98,28 @@ void peer_info_free (struct peer_info *p) {
     free(p);
 }
 
+/*
+ * If the peer is still valid, returns it.
+ * If the peer has timed out, frees it and returns NULL
+ * Used after a HASH_FIND_PEER to validate the found peer
+ */
+struct peer_info* peer_info_validate (struct peer_info **list, struct peer_info *p) {
+    if(!p) {
+        return NULL;
+    }
+    if(!p->purgeable) {
+        return p;
+    }
+    time_t now = time(NULL);
+    if(p->last_seen >= now - REGISTRATION_TIMEOUT) {
+        return p;
+    }
+    HASH_DEL(*list, p);
+    mgmt_event_post(N3N_EVENT_PEER,N3N_EVENT_PEER_PURGE,p);
+    peer_info_free(p);
+    return NULL;
+}
+
 inline char *peer_info_get_hostname (struct peer_info *p) {
     return p->hostname;
 }
@@ -120,6 +142,8 @@ size_t purge_peer_list (struct peer_info **peer_list,
     }
 
     HASH_ITER(hh, *peer_list, scan, tmp) {
+        // TODO: untangle the tcp_connections usage and use
+        // peer_info_validate() as the core of this loop
         if(scan->purgeable && scan->last_seen < purge_before) {
             if((scan->socket_fd >=0) && (scan->socket_fd != socket_not_to_close)) {
                 if(tcp_connections) {
diff --git a/src/peer_info.h b/src/peer_info.h
index f8ab87a..7d5290b 100644
--- a/src/peer_info.h
+++ b/src/peer_info.h
@@ -48,6 +48,7 @@ typedef struct peer_info peer_info_t;
 void peer_info_init (struct peer_info *, const n2n_mac_t mac);
 struct peer_info* peer_info_malloc (const n2n_mac_t mac);
 void peer_info_free (struct peer_info *);
+struct peer_info* peer_info_validate (struct peer_info **, struct peer_info *);
 
 char *peer_info_get_hostname (struct peer_info *);
 
diff --git a/src/sn_utils.c b/src/sn_utils.c
index 1edd775..99915df 100644
--- a/src/sn_utils.c
+++ b/src/sn_utils.c
@@ -1195,7 +1195,11 @@ static int update_edge (struct n3n_runtime_data *sss,
     // if unknown, make sure it is also not known by IP address
     if(NULL == scan) {
         HASH_ITER(hh,comm->edges,iter,tmp) {
-            // TODO: needs ipv6 support
+            // TODO:
+            // - needs ipv6 support
+            // - I suspect that this can leak TCP connections
+            // - convert to using a peer_info_*() call for manipulating the
+            //   peer info lists
             if(iter->dev_addr.net_addr == reg->dev_addr.net_addr) {
                 scan = iter;
                 HASH_DEL(comm->edges, scan);
@@ -1206,6 +1210,8 @@ static int update_edge (struct n3n_runtime_data *sss,
         }
     }
 
+    scan = peer_info_validate(&comm->edges, scan);
+
     if(NULL == scan) {
         /* Not known */
         if(handle_remote_auth(sss, &(reg->auth), answer_auth, comm) == 0) {