From 035fcc56ef6020ac55bf3be4a175f8776170c54c Mon Sep 17 00:00:00 2001
From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 16 Sep 2022 20:14:14 +0200
Subject: [PATCH] host: keep multiple endpoint candidates, one for each type

Some discovery methods might be more reliable than others. Avoid having
them overwrite each other's discovery result

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 host.c | 38 +++++++++++++++++++++++++++++++-------
 host.h | 11 ++++++++++-
 pex.c  | 10 +++++++---
 3 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/host.c b/host.c
index e0c5827..aa3c5b2 100644
--- a/host.c
+++ b/host.c
@@ -360,6 +360,35 @@ void network_hosts_update_done(struct network *net)
 	return __network_hosts_update_done(net, false);
 }
 
+static union network_endpoint *
+network_peer_next_endpoint(struct network_peer *peer)
+{
+	union network_endpoint *ep;
+	int i;
+
+	for (i = 0; i < __ENDPOINT_TYPE_MAX; i++) {
+		int cur = peer->state.next_endpoint_idx;
+
+		if (++peer->state.next_endpoint_idx == __ENDPOINT_TYPE_MAX)
+			peer->state.next_endpoint_idx = 0;
+
+		ep = &peer->state.next_endpoint[cur];
+		if (cur == ENDPOINT_TYPE_STATIC &&
+			(!peer->endpoint ||
+		     network_get_endpoint(ep, AF_UNSPEC, peer->endpoint, peer->port,
+					  peer->state.connect_attempt++)))
+			continue;
+
+		if (!ep->sa.sa_family)
+			continue;
+
+		return ep;
+	}
+
+	return NULL;
+}
+
+
 static void
 network_hosts_connect_cb(struct uloop_timeout *t)
 {
@@ -381,13 +410,8 @@ network_hosts_connect_cb(struct uloop_timeout *t)
 		if (peer->state.connected)
 			continue;
 
-		ep = &peer->state.next_endpoint;
-		if (peer->endpoint &&
-		    network_get_endpoint(ep, AF_UNSPEC, peer->endpoint, peer->port,
-					 peer->state.connect_attempt++))
-			continue;
-
-		if (!ep->sa.sa_family)
+		ep = network_peer_next_endpoint(peer);
+		if (!ep)
 			continue;
 
 		if (memcmp(ep, &peer->state.endpoint, sizeof(*ep)) != 0)
diff --git a/host.h b/host.h
index 5eed711..b3fef03 100644
--- a/host.h
+++ b/host.h
@@ -5,6 +5,14 @@
 #ifndef __UNETD_HOST_H
 #define __UNETD_HOST_H
 
+enum peer_endpoint_type {
+	ENDPOINT_TYPE_STATIC,
+	ENDPOINT_TYPE_PEX,
+	ENDPOINT_TYPE_ENDPOINT_NOTIFY,
+	ENDPOINT_TYPE_ENDPOINT_PORT_NOTIFY,
+	__ENDPOINT_TYPE_MAX,
+};
+
 struct network_peer {
 	struct vlist_node node;
 	uint8_t key[CURVE25519_KEY_SIZE];
@@ -25,7 +33,8 @@ struct network_peer {
 		union network_addr local_ep_addr;
 		union network_endpoint endpoint;
 
-		union network_endpoint next_endpoint;
+		uint8_t next_endpoint_idx;
+		union network_endpoint next_endpoint[__ENDPOINT_TYPE_MAX];
 		uint64_t last_ep_update;
 
 		uint64_t rx_bytes;
diff --git a/pex.c b/pex.c
index 65cb1e5..b228576 100644
--- a/pex.c
+++ b/pex.c
@@ -485,7 +485,7 @@ network_pex_recv_peers(struct network *net, struct network_peer *peer,
 		D_PEER(net, peer, "received peer address for %s",
 		       network_peer_name(cur));
 		flags = ntohs(data->flags);
-		ep = &cur->state.next_endpoint;
+		ep = &cur->state.next_endpoint[ENDPOINT_TYPE_PEX];
 		ep->sa.sa_family = (flags & PEER_EP_F_IPV6) ? AF_INET6 : AF_INET;
 		addr = network_endpoint_addr(ep, &len);
 		memcpy(addr, data->addr, len);
@@ -904,6 +904,7 @@ global_pex_recv(void *msg, size_t msg_len, struct sockaddr_in6 *addr)
 	char buf[INET6_ADDRSTRLEN];
 	void *data;
 	int addr_len;
+	int ep_idx = ENDPOINT_TYPE_ENDPOINT_NOTIFY;
 
 	if (stun_msg_is_valid(msg, msg_len)) {
 		avl_for_each_element(&networks, net, node)
@@ -949,6 +950,9 @@ global_pex_recv(void *msg, size_t msg_len, struct sockaddr_in6 *addr)
 	case PEX_MSG_ENDPOINT_PORT_NOTIFY:
 		if (hdr->len < sizeof(struct pex_endpoint_port_notify))
 			break;
+
+		ep_idx = ENDPOINT_TYPE_ENDPOINT_PORT_NOTIFY;
+		fallthrough;
 	case PEX_MSG_ENDPOINT_NOTIFY:
 		peer = pex_msg_peer(net, hdr->id);
 		if (!peer)
@@ -958,14 +962,14 @@ global_pex_recv(void *msg, size_t msg_len, struct sockaddr_in6 *addr)
 		  inet_ntop(addr->sin6_family, network_endpoint_addr((void *)addr, &addr_len),
 			    buf, sizeof(buf)));
 
-		memcpy(&peer->state.next_endpoint, addr, sizeof(*addr));
+		memcpy(&peer->state.next_endpoint[ep_idx], addr, sizeof(*addr));
 		if (hdr->opcode == PEX_MSG_ENDPOINT_PORT_NOTIFY) {
 			struct pex_endpoint_port_notify *port = data;
 			union network_endpoint host_ep = {
 				.in6 = *addr
 			};
 
-			peer->state.next_endpoint.in.sin_port = port->port;
+			peer->state.next_endpoint[ep_idx].in.sin_port = port->port;
 			if (net->pex.num_hosts < NETWORK_PEX_HOSTS_LIMIT)
 				network_pex_create_host(net, &host_ep, 120);
 		}
-- 
2.30.2