Introduce a datapathHandler that implements hooks that will
receive packets from the tstun.Wrapper. This commit does not wire
those up just yet.
Perform DNAT from Magic IP to Transit IP on outbound flows on clients,
and reverse SNAT in the reverse direction.
Perform DNAT from Transit IP to final destination IP on outbound flows
on connectors, and reverse SNAT in the reverse direction.
Introduce FlowTable to cache validated flows by 5-tuple for fast lookups
after the first packet.
Flow expiration is not covered, and is intended as future work before
the feature is officially released.
Fixestailscale/corp#34249Fixestailscale/corp#35995
Co-authored-by: Fran Bull <fran@tailscale.com>
Signed-off-by: Michael Ben-Ami <mzb@tailscale.com>
This hook addition is motivated by the Connectors 2025 work, in which
NATed "Transit IPs" are used to route interesting traffic to the
appropriate peer, without advertising the actual real IPs.
It overlaps with #17858, and specifically with the WIP PR #17861.
If that work completes, this hook may be replaced by other ones
that fit the new WireGuard configuration paradigm.
Fixestailscale/corp#37146
Signed-off-by: Michael Ben-Ami <mzb@tailscale.com>
Add PacketMatch hooks to the packet filter, allowing extensions to
customize filtering decisions:
- IngressAllowHooks: checked in RunIn after pre() but before the
standard runIn4/runIn6 match rules. Hooks can accept packets to
destinations outside the local IP set. First match wins; the
returned why string is used for logging.
- LinkLocalAllowHooks: checked inside pre() for both ingress and
egress, providing exceptions to the default policy of dropping
link-local unicast packets. First match wins. The GCP DNS address
(169.254.169.254) is always allowed regardless of hooks.
PacketMatch returns (match bool, why string) to provide a log reason
consistent with the existing filter functions.
Hooks are registered via the new FilterHooks struct in ipnext.Hooks
and wired through to filter.Filter in LocalBackend.updateFilterLocked.
Fixestailscale/corp#35989Fixestailscale/corp#37207
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Michael Ben-Ami <mzb@tailscale.com>
app connector packets
We introduce the Conn25PacketHooks interface to be used as a nil-able
field in userspaceEngine. The engine then plumbs through the functions
to the corresponding tstun.Wrapper intercepts.
The new intercepts run pre-filter when egressing toward WireGuard,
and post-filter when ingressing from WireGuard. This is preserve the
design invariant that the filter recognizes the traffic as interesting
app connector traffic.
This commit does not plumb through implementation of the interface, so
should be a functional no-op.
Fixestailscale/corp#35985
Signed-off-by: Michael Ben-Ami <mzb@tailscale.com>
dnstype.Resolver adds a boolean UseWithExitNode that controls
whether the resolver should be used in tailscale exit node contexts
(not wireguard exit nodes). If UseWithExitNode resolvers are found,
they are installed as the global resolvers. If no UseWithExitNode resolvers
are found, the exit node resolver continues to be installed as the global
resolver. Split DNS Routes referencing UseWithExitNode resolvers are also
installed.
Updates #8237Fixestailscale/corp#30906Fixestailscale/corp#30907
Signed-off-by: Michael Ben-Ami <mzb@tailscale.com>
