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
@@ -0,0 +1,149 @@
|
||||
---
|
||||
name: pia-vpn
|
||||
description: Connect this container's traffic through a PIA VPN tunnel over WireGuard, or diagnose one that is not working. Use when asked to enable, route through, check, or tear down a VPN, when traffic needs to leave from a different location, or when DNS or connectivity broke after a VPN was brought up.
|
||||
---
|
||||
|
||||
# PIA VPN
|
||||
|
||||
Bring this container's traffic out through Private Internet Access over
|
||||
WireGuard, using the API PIA documents for headless use.
|
||||
|
||||
Run `sudo ~/.claude/skills/pia-vpn/pia-wg.sh` with `up`, `up --full`, `down` or
|
||||
`status`. Read the rest of this page before the first `up --full` — two of the
|
||||
behaviours below are actively misleading if you meet them without warning.
|
||||
|
||||
## Before anything else: what the toggle does not do
|
||||
|
||||
Triple-C's **VPN support** setting grants three things — `CAP_NET_ADMIN`, the
|
||||
`/dev/net/tun` device, and the `net.ipv4.conf.all.src_valid_mark` sysctl — and
|
||||
stops there. It starts no client, builds no tunnel and changes no route.
|
||||
|
||||
So "the VPN is enabled but traffic isn't going through it" is normally not a
|
||||
fault. It means the capability is present and nothing has used it yet. Check
|
||||
with `status` before assuming something is broken.
|
||||
|
||||
If the toggle is off, the script says so and names the setting. It cannot be
|
||||
turned on from inside the container; the user changes it in Config → Runtime,
|
||||
and it recreates the container on the next start (home and `.claude` volumes
|
||||
are preserved — it is not a Reset).
|
||||
|
||||
## Two modes
|
||||
|
||||
| | routes | use when |
|
||||
|---|---|---|
|
||||
| `up` | only `1.1.1.1/32` | verifying the tunnel works without disturbing anything |
|
||||
| `up --full` | all public traffic | you actually want traffic leaving via PIA |
|
||||
|
||||
Prefer `up` first. It proves the handshake, credentials and region are good
|
||||
while your own connectivity is untouched, so a failure is cheap.
|
||||
|
||||
**`up --full` routes Claude Code's own API traffic through PIA.** If the tunnel
|
||||
drops, that traffic stops until it recovers or you run `down`. Say so before
|
||||
running it — the user may be mid-session, and they will experience the failure
|
||||
as Claude going away, not as a VPN problem.
|
||||
|
||||
## Trap 1: a full tunnel takes DNS with it
|
||||
|
||||
The container resolves through an address on the Docker network — under Docker
|
||||
Desktop, `192.168.65.7` — which sits **outside** the container's own subnet. A
|
||||
default route of `0.0.0.0/0`, or the `0.0.0.0/1` + `128.0.0.0/1` pair, captures
|
||||
it and posts every lookup into a tunnel that cannot carry private traffic.
|
||||
|
||||
Nothing resolves after that. The visible symptom is Claude Code reporting it
|
||||
cannot connect, because `api.anthropic.com` no longer resolves:
|
||||
|
||||
```
|
||||
$ curl https://api.anthropic.com/v1/messages
|
||||
* Could not resolve host: api.anthropic.com (rc=6)
|
||||
```
|
||||
|
||||
`pia-wg.sh` already handles this: it routes `10.0.0.0/8`, `172.16.0.0/12`,
|
||||
`192.168.0.0/16` and `169.254.0.0/16` back via the original gateway, then pins
|
||||
PIA's own resolvers through the tunnel with `/32` routes that outrank the
|
||||
`10/8` exclusion. If you ever route traffic by hand, you owe both halves — the
|
||||
exclusions *and* a resolver reachable from wherever you pointed the default.
|
||||
|
||||
## Trap 2: an IP-literal health check cannot see a dead resolver
|
||||
|
||||
`curl https://1.1.1.1/cdn-cgi/trace` needs no DNS, so it returns a cheerful
|
||||
PIA exit address while name resolution is entirely broken. A tunnel verified
|
||||
that way looks perfect and works for nothing.
|
||||
|
||||
`status` resolves a real name for this reason. Trust its `DNS:` line, and if
|
||||
you check by hand, resolve a name rather than fetching an address.
|
||||
|
||||
## Trap 3: no tunnel survives a restart, and it fails open
|
||||
|
||||
The network namespace is rebuilt every time the container starts, and nothing
|
||||
inside reconnects anything. After a stop/start, Reset or any config change that
|
||||
recreates the container, the interface and its routes are gone.
|
||||
|
||||
State under `/run/pia-wg` rides the snapshot and persists, so leftover files
|
||||
make it look as though the tunnel is still configured. It is not. Traffic goes
|
||||
out the real address with no error and nothing visibly different.
|
||||
|
||||
Never infer from `/run/pia-wg` that a tunnel is up. Run `status` — if the
|
||||
handshake line is missing, there is no tunnel. Re-run `up` after every start.
|
||||
|
||||
## Credentials
|
||||
|
||||
Two lines in `~/pia-creds` — username, then password:
|
||||
|
||||
```
|
||||
p1234567
|
||||
your-password
|
||||
```
|
||||
|
||||
Set `PIA_CREDS` to use a different path. Treat the contents as secret: never
|
||||
print the file, never echo the values, and never include them in a commit, a
|
||||
log or a message. The script reads it directly and does not echo it.
|
||||
|
||||
## Regions
|
||||
|
||||
Defaults to `us_chicago`. Override with `PIA_REGION`:
|
||||
|
||||
```bash
|
||||
sudo PIA_REGION=uk_london ~/.claude/skills/pia-vpn/pia-wg.sh up --full
|
||||
```
|
||||
|
||||
List the ids:
|
||||
|
||||
```bash
|
||||
curl -s https://serverlist.piaservers.net/vpninfo/servers/v6 \
|
||||
| head -1 | jq -r '.regions[].id'
|
||||
```
|
||||
|
||||
## Verifying
|
||||
|
||||
`status` prints three things — handshake, DNS, and the public address:
|
||||
|
||||
```
|
||||
latest handshake: 2 seconds ago
|
||||
transfer: 92 B received, 180 B sent
|
||||
DNS: ok (via 10.0.0.243 10.0.0.242)
|
||||
public IP: 64.113.5.244
|
||||
```
|
||||
|
||||
All three matter. A handshake with `DNS: BROKEN` is trap 1. A handshake with an
|
||||
unchanged public address means routing did not take — you are probably in `up`
|
||||
rather than `up --full`.
|
||||
|
||||
## Tearing down
|
||||
|
||||
`down` restores `resolv.conf` from its backup and removes exactly the routes
|
||||
that were added, in reverse order, then deletes the interface. It is safe to
|
||||
run when nothing is up. Confirm afterwards that the public address is back to
|
||||
the container's own.
|
||||
|
||||
## What this deliberately does not do
|
||||
|
||||
- **No killswitch.** Blocking non-tunnel egress needs `iptables`, which is not
|
||||
in the image, and would cut Claude Code's API traffic whenever the tunnel is
|
||||
down. If the user needs guaranteed egress rather than convenient egress, say
|
||||
so plainly rather than improvising one — it is a real design decision.
|
||||
- **No autostart.** There is no service manager in the container and Triple-C
|
||||
has no start hook, so nothing can re-establish the tunnel automatically.
|
||||
- **Not PIA's desktop client.** `pia-daemon` and `piactl` are installable but
|
||||
cannot work headless: the daemon never accepts a client connection without
|
||||
the GUI, and `piactl --help` states that connecting requires it. If you find
|
||||
one installed, it is not a working alternative to this script.
|
||||
Reference in New Issue
Block a user