Ship a pia-vpn skill with the VPN support toggle
The toggle grants CAP_NET_ADMIN and /dev/net/tun and stops there, which users reasonably read as "turn the VPN on" — the gap between the two is the reported bug that the default network does not route through a VPN. Close it by giving the container an agent-usable way to build the tunnel, rather than leaving each project to rediscover it. container/skills/ is baked to /opt/triple-c-skills and installed into ~/.claude/skills/ by entrypoint.sh from VPN_SUPPORT_ENABLED, mirroring how Mission Control installs its own. Staged under /opt because ~/.claude is a volume mount that would mask an image copy from first start. Three details that are not incidental: - The variable is sent as 0 rather than omitted when off, because ~/.claude persists: entrypoint has to be *told* to remove a skill left by an earlier run with the toggle on, and an absent variable cannot say that. A stale skill is worse than none, since it instructs an agent to use a capability the container no longer has. - It is reserved in RESERVED_ENV_EXACT alongside MISSION_CONTROL_ENABLED, or a custom env var of the same name could claim the skill without the capability behind it. Covered by a test. - The skill is re-copied on every start, rm -rf'd first, so fixes reach existing projects and files dropped from a later version do not linger. The skill itself carries the three things that are easy to get wrong: that a full tunnel captures the Docker resolver and takes DNS down with it, that an IP-literal health check cannot see a dead resolver, and that no tunnel survives a restart while /run state riding the snapshot makes it look as though one did. It also states what it deliberately does not do — no killswitch, no autostart — so an agent proposes those as decisions rather than improvising them. pia-wg.sh preflights CAP_NET_ADMIN by capability bit rather than letting the first `ip` call fail with a bare EPERM that points nowhere near the setting that needs changing. Credentials stay in a file (~/pia-creds, PIA_CREDS to override) rather than the environment, where docker inspect and every process in the container would see them. Tested: install/refresh/remove/no-op paths of install_feature_skill against the real function; preflight with and without the capability; and a full up --full / down round trip, confirming DNS via PIA's resolvers, api.anthropic.com reachable through the exit, and routes and resolv.conf restored on teardown. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
Claude Opus 5
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#!/usr/bin/env bash
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# PIA over WireGuard, headless.
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#
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# PIA's desktop client (pia-daemon + piactl) cannot work here: its daemon never
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# accepts a client connection without the GUI running, and `piactl --help` says
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# as much. This talks to PIA's public API directly instead, which is the path
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# PIA themselves document for headless use.
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#
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# sudo pia-wg.sh up tunnel up, only 1.1.1.1 routed through it (safe test)
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# sudo pia-wg.sh up --full tunnel up, all *public* traffic exits via PIA
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# sudo pia-wg.sh down tear down, restoring DNS and routes
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# sudo pia-wg.sh status handshake, DNS and current public IP
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#
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# Requires the project's "VPN support" setting (Config -> Runtime) to be on.
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#
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# PIA_CREDS credentials file, two lines: username, then password
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# (default ~/pia-creds; never echoed by this script)
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# PIA_REGION region id (default us_chicago). List them with:
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# curl -s https://serverlist.piaservers.net/vpninfo/servers/v6 \
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# | head -1 | jq -r '.regions[].id'
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set -euo pipefail
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CREDS=${PIA_CREDS:-/home/claude/pia-creds}
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REGION=${PIA_REGION:-us_chicago}
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IFACE=pia0
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STATE=/run/pia-wg
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# Kept off the tunnel in --full mode. The container's DNS resolver, the Docker
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# host network (host.docker.internal, any host-side Ollama), sibling containers
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# and the LAN all live in here. PIA cannot route any of it, so without these
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# exclusions the container reaches the public internet and nothing else --
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# including, fatally, its own resolver.
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PRIVATE_NETS="10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 169.254.0.0/16"
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# Args are joined with spaces so a long message can be written as several
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# source lines without the indentation ending up in the output.
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die() { echo "pia-wg: $*" >&2; exit 1; }
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preflight() {
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[ "$(id -u)" = 0 ] || die "run with sudo"
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# CAP_NET_ADMIN is bit 12. Checking it by name gives a usable error; without
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# it the first `ip` call fails with a bare "Operation not permitted" that
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# points nowhere near the setting that actually needs changing.
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local caps
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caps=$(awk '/^CapEff:/{print $2}' /proc/self/status)
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if [ $(( 0x$caps & 0x1000 )) -eq 0 ]; then
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die "this container has no CAP_NET_ADMIN." \
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"Turn on \"VPN support\" in Config -> Runtime and start the project" \
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"again. That recreates the container; the home and .claude volumes" \
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"are preserved, so nothing in them is lost."
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fi
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[ -e /dev/net/tun ] || \
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die "/dev/net/tun is missing." \
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"Same fix: turn on \"VPN support\" in Config -> Runtime. If it is" \
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"already on, the Docker host's kernel is missing the tun module."
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command -v wg >/dev/null || die "wireguard-tools is not installed."
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[ -r "$CREDS" ] || \
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die "no credentials at $CREDS." \
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"Two lines are expected: username, then password." \
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"Set PIA_CREDS to read them from somewhere else."
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}
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# Record every route we add so teardown removes exactly those and nothing else.
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add_route() { ip route add $1 2>/dev/null && echo "$1" >> "$STATE/routes" || true; }
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up() {
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preflight
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mkdir -p "$STATE"; cd "$STATE"
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[ -f ca.rsa.4096.crt ] || curl -sf -m 20 -o ca.rsa.4096.crt \
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https://raw.githubusercontent.com/pia-foss/manual-connections/master/ca.rsa.4096.crt \
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|| die "could not fetch PIA's CA certificate"
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local u p tok srv sip scn priv pub resp ep gw dns
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u=$(sed -n 1p "$CREDS"); p=$(sed -n 2p "$CREDS")
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tok=$(curl -sf -m 25 -u "$u:$p" \
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https://www.privateinternetaccess.com/gtoken/generateToken | jq -r .token)
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[ -n "$tok" ] && [ "$tok" != null ] || die "PIA authentication failed - check $CREDS"
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curl -sf -m 30 https://serverlist.piaservers.net/vpninfo/servers/v6 | head -1 > servers.json
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srv=$(jq -r --arg r "$REGION" '.regions[] | select(.id==$r) | .servers.wg[0]' servers.json)
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sip=$(echo "$srv" | jq -r .ip); scn=$(echo "$srv" | jq -r .cn)
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[ -n "$sip" ] && [ "$sip" != null ] || die "no WireGuard server for region $REGION"
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priv=$(wg genkey); pub=$(echo "$priv" | wg pubkey)
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printf '%s' "$priv" > wg.priv; chmod 600 wg.priv
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# PIA pins its certificate to the server's common name, which is why this
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# connects by CN and lets --connect-to point that name at the real address.
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resp=$(curl -sf -m 25 -G --connect-to "$scn::$sip:" --cacert ca.rsa.4096.crt \
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--data-urlencode "pt=$tok" --data-urlencode "pubkey=$pub" \
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"https://$scn:1337/addKey")
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[ "$(echo "$resp" | jq -r .status)" = OK ] || die "key registration failed: $resp"
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: > "$STATE/routes"
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ip link del "$IFACE" 2>/dev/null || true
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ip link add "$IFACE" type wireguard
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wg set "$IFACE" private-key wg.priv \
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peer "$(echo "$resp" | jq -r .server_key)" \
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endpoint "$(echo "$resp" | jq -r .server_ip):$(echo "$resp" | jq -r .server_port)" \
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allowed-ips 0.0.0.0/0 persistent-keepalive 25
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ip addr add "$(echo "$resp" | jq -r .peer_ip)/32" dev "$IFACE"
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ip link set "$IFACE" up
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if [ "${1:-}" = "--full" ]; then
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# Pin the endpoint to the pre-existing gateway first, so the tunnel's own
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# packets do not try to route through the tunnel. Then beat the default
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# route with two half-routes rather than replacing it -- nothing to restore
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# on teardown, and the container keeps working if this script dies midway.
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ep=$(echo "$resp" | jq -r .server_ip)
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gw=$(ip route show default | awk '{print $3; exit}')
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add_route "$ep/32 via $gw"
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add_route "0.0.0.0/1 dev $IFACE"
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add_route "128.0.0.0/1 dev $IFACE"
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# Keep container, host and LAN traffic off the tunnel. Longer prefixes than
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# the two halves above, so these win.
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for n in $PRIVATE_NETS; do add_route "$n via $gw"; done
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# PIA's resolver lives inside 10/8, so pin it back through the tunnel with a
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# /32 -- longer still, so it beats the 10.0.0.0/8 exclusion just added.
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# Using PIA's resolver rather than the container's keeps DNS from leaking,
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# and the container's own resolver is unreachable from inside the tunnel.
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dns=$(echo "$resp" | jq -r '.dns_servers[]? // empty' | head -2)
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if [ -n "$dns" ]; then
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cp /etc/resolv.conf "$STATE/resolv.conf.bak"
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for d in $dns; do add_route "$d/32 dev $IFACE"; done
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# resolv.conf is a bind mount: write through it, never replace it.
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for d in $dns; do echo "nameserver $d"; done > /etc/resolv.conf
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else
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echo "pia-wg: warning - PIA returned no DNS servers; leaving resolv.conf alone" >&2
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fi
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echo "full tunnel: public traffic exits via PIA; private ranges stay local"
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else
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add_route "1.1.1.1/32 dev $IFACE"
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echo "test route only: 1.1.1.1 goes via PIA, everything else unchanged"
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fi
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sleep 2
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status
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}
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down() {
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[ "$(id -u)" = 0 ] || die "run with sudo"
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if [ -f "$STATE/resolv.conf.bak" ]; then
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cat "$STATE/resolv.conf.bak" > /etc/resolv.conf
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rm -f "$STATE/resolv.conf.bak"
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fi
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if [ -f "$STATE/routes" ]; then
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# Reverse order: the specific overrides go before the ranges they sit in.
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tac "$STATE/routes" | while read -r r; do
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[ -n "$r" ] && ip route del $r 2>/dev/null || true
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done
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rm -f "$STATE/routes"
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fi
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ip link del "$IFACE" 2>/dev/null || true
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echo "tunnel down"
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}
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status() {
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wg show "$IFACE" 2>/dev/null | grep -E "latest handshake|transfer" || echo "no tunnel up"
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# Resolve a name, not an IP literal. A curl to 1.1.1.1 succeeds while DNS is
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# completely broken, which is exactly how a dead resolver goes unnoticed.
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printf 'DNS: '
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if timeout 10 getent hosts api.anthropic.com >/dev/null 2>&1; then
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echo "ok (via $(sed -n 's/^nameserver //p' /etc/resolv.conf | tr '\n' ' '))"
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else
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echo "BROKEN - cannot resolve api.anthropic.com"
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fi
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echo -n "public IP: "
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curl -s -m 20 https://1.1.1.1/cdn-cgi/trace | sed -n 's/^ip=//p'
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}
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case "${1:-}" in
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up) shift; up "${1:-}" ;;
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down) down ;;
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status) status ;;
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*) sed -n '2,20p' "$0" | sed 's/^# \{0,1\}//'; exit 1 ;;
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esac
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