Coordinate custom-map downloads with the multiplayer deadline

Co-authored-by: Jean-LucTch <88255067+Jean-LucTch@users.noreply.github.com>

Server/server_host.cpp

@@ -211,7 +211,7 @@ void Host::fetching(Guest &guest) {
         guest.fetching_since = now_;
         log_("[map] " + guest_name(guest) + " is downloading the map");
     }
-    if (now_ - guest.fetching_since > map_fetch_limit_us) return;
+    if (map_fetch_policy::host_expired(guest.fetching_since, now_)) return;
     if (!guest.handshaken) guest.connected_at = now_;
     else if (guest.travel_since) guest.travel_since = now_;
 }
@@ -1093,6 +1093,9 @@ void Host::receive(std::uint64_t peer, std::span<const std::uint8_t> bytes, std:
     if (!decoded || decoded->session != secret_ || decoded->source != peer)
         return drop(peer, "Join code, sender identity, or multiplayer protocol did not match.");
     const auto &p = *decoded;
+    if (link->fetching_since && (!link->handshaken || link->travel_since) &&
+        map_fetch_policy::host_expired(link->fetching_since, now_))
+        return drop(peer, "The server stopped waiting for the map download.");
     link->traffic.total.in[traffic_kind(p.kind)] += bytes.size();
     traffic_.total.in[traffic_kind(p.kind)] += bytes.size();
     switch (p.kind) {
@@ -1790,6 +1793,11 @@ void Host::tick(std::uint64_t now) {
         auto &g = *(it++)->second;
         // Authorized arrivals get time for loading; this deadline is absolute, so
         // requests cannot hold an unused slot indefinitely.
+        if (g.fetching_since && (!g.handshaken || g.travel_since) &&
+            map_fetch_policy::host_expired(g.fetching_since, now_)) {
+            drop(g.member.id, "The server stopped waiting for the map download.");
+            continue;
+        }
         const std::uint64_t handshake_timeout = g.map_authorized ? 180000000 : 8000000;
         if (g.handshaken && g.travel_since) {
             if (now_ - g.travel_since > 180000000) drop(g.member.id, "Could not finish loading the new map.");