feat(packaging): ship a node firewall profile for inbound WebRTC

The packages carried a profile for LAN casting and none for the node's own
peer traffic, on the reasoning that the node exposes only a loopback admin
API. That is true of its administration surface and false of its transport.

WebRTC binds an ephemeral UDP port per connection, so there is no fixed port
to open, and a connection succeeds only if one side can initiate. Browsers
publish their host candidate as an mDNS `<uuid>.local` name, which aioice
cannot resolve on any platform and discards — so the node can never call a
browser back, and the browser must call the node. A node that refuses
unsolicited inbound UDP is unreachable from every browser on its own LAN,
leaving reflexive candidates, which fail whenever both peers share one public
IP and the router will not hairpin.

Hit twice in one session on two different hosts: a firewalld zone narrowed to
mdns + 19550-19553/tcp, and a ufw host with default deny-incoming. Both
presented as "the app cannot connect", neither as a firewall message.

Passive like the cast profile: packaged, not activated. The guide says to
scope it to a LAN zone or source, including the libvirt case, where traffic
from a guest to its own hypervisor is not masqueraded and so must be scoped
to the guest subnet rather than the LAN.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DtfG7z6wHWj8RKHCvxQtY1

1 files changed, 12 insertions, 4 deletions

diff --git a/packaging/build/build-node.sh b/packaging/build/build-node.sh
index 9ad4968..bd81096 100755
--- a/packaging/build/build-node.sh
+++ b/packaging/build/build-node.sh
@@ -75,12 +75,20 @@ cp "$REPO/packaging/systemd/meshbay-node.service" \
 cp "$REPO/packaging/systemd/meshbay-node-user.service" \
    "$ROOT/usr/lib/systemd/user/meshbay-node.service"
 
-# --- Firewall profile ---------------------------------------------------------
-# UFW (Ubuntu/Debian) — carries the "MeshBay Cast" LAN-casting profile only.
-# The node's own admin surface is a loopback API (127.0.0.1, token-gated) and
-# is never firewall-exposed, so it ships no profile.
+# --- Firewall profiles --------------------------------------------------------
+# The node's admin surface is a loopback API (127.0.0.1, token-gated) and is
+# never firewall-exposed. Its *peer* traffic is: WebRTC binds an ephemeral UDP
+# port per connection, and a peer that publishes an unroutable address — every
+# browser does, as an mDNS .local name aioice cannot resolve — can only be
+# reached if it calls the node. A node refusing unsolicited inbound UDP is
+# therefore unreachable from browsers on its own LAN. Both profiles are passive:
+# packaged, not activated, and meant to be scoped to a LAN zone/source.
 mkdir -p "$ROOT/etc/ufw/applications.d"
 cp "$REPO/packaging/firewall/ufw/meshbay" \
    "$ROOT/etc/ufw/applications.d/"
 
+mkdir -p "$ROOT/usr/lib/firewalld/services"
+cp "$REPO/packaging/firewall/firewalld/meshbay-node.xml" \
+   "$ROOT/usr/lib/firewalld/services/"
+
 echo "==> meshbay-node staging ready at $ROOT"