We were previously using the netlink API to see if there are chains/rules that
already exist. This works fine in environments where there is either full
nftable support or no support at all. However, we have identified certain
environments which have partial nftable support and the only feasible way of
detecting such an environment is to try to create some of the chains that we
need.
This adds a check to create a dummy postrouting chain which is immediately
deleted. The goal of the check is to ensure we are able to use nftables and
that it won't error out later. This check is only done in the path where we
detected that the system has no preexisting nftable rules.
Updates #5621
Updates #8555
Updates #8762
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Just a refactor to consolidate the firewall detection logic in a single
package so that it can be reused in a later commit by containerboot.
Updates #9310
Signed-off-by: Maisem Ali <maisem@tailscale.com>
Go style is for error variables to start with "err" (or "Err")
and for error types to end in "Error".
Updates #cleanup
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit replaces the TS_DEBUG_USE_NETLINK_NFTABLES envknob with
a TS_DEBUG_FIREWALL_MODE that should be set to either 'iptables' or
'nftables' to select firewall mode manually, other wise tailscaled
will automatically choose between iptables and nftables depending on
environment and system availability.
updates: #319
Signed-off-by: KevinLiang10 <kevinliang@tailscale.com>
Exclide GOARCHs including: mips, mips64, mips64le, mipsle, riscv64.
These archs are not supported by gvisor.dev/gvisor/pkg/hostarch.
Fixes: #391
Signed-off-by: KevinLiang10 <kevinliang@tailscale.com>
This isn't currently supported due to missing support in upstream
dependencies, and also we don't use this package anywhere right now.
Just conditionally skip this for now.
Fixes#7268
Change-Id: Ie7389c2c0816b39b410c02a7276051a4c18b6450
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
This package is an initial implementation of something that can read
netfilter and iptables rules from the Linux kernel without needing to
shell out to an external utility; it speaks directly to the kernel using
syscalls and parses the data returned.
Currently this is read-only since it only knows how to parse a subset of
the available data.
Signed-off-by: Andrew Dunham <andrew@tailscale.com>
Change-Id: Iccadf5dcc081b73268d8ccf8884c24eb6a6f1ff5
