* firewall: add option to send REJECT replies
This change allows you to configure the firewall to send REJECT packets
when a packet is denied.
firewall:
# Action to take when a packet is not allowed by the firewall rules.
# Can be one of:
# `drop` (default): silently drop the packet.
# `reject`: send a reject reply.
# - For TCP, this will be a RST "Connection Reset" packet.
# - For other protocols, this will be an ICMP port unreachable packet.
outbound_action: drop
inbound_action: drop
These packets are only sent to established tunnels, and only on the
overlay network (currently IPv4 only).
$ ping -c1 192.168.100.3
PING 192.168.100.3 (192.168.100.3) 56(84) bytes of data.
From 192.168.100.3 icmp_seq=2 Destination Port Unreachable
--- 192.168.100.3 ping statistics ---
2 packets transmitted, 0 received, +1 errors, 100% packet loss, time 31ms
$ nc -nzv 192.168.100.3 22
(UNKNOWN) [192.168.100.3] 22 (?) : Connection refused
This change also modifies the smoke test to capture tcpdump pcaps from
both the inside and outside to inspect what is going on over the wire.
It also now does TCP and UDP packet tests using the Nmap version of
ncat.
* calculate seq and ack the same was as the kernel
The logic a bit confusing, so we copy it straight from how the kernel
does iptables `--reject-with tcp-reset`:
- https://github.com/torvalds/linux/blob/v5.19/net/ipv4/netfilter/nf_reject_ipv4.c#L193-L221
* cleanup
* Add nss-lookup to the systemd wants to ensure DNS is running before starting nebula
* Add Ansible & example service scripts
* Fix#797
* Align Ansible scripts and examples
Co-authored-by: John Maguire <contact@johnmaguire.me>
These new helpers make the code a lot cleaner. I confirmed that the
simple helpers like `atomic.Int64` don't add any extra overhead as they
get inlined by the compiler. `atomic.Pointer` adds an extra method call
as it no longer gets inlined, but we aren't using these on the hot path
so it is probably okay.
By default, Nebula replies to packets it has no tunnel for with a `recv_error` packet. This packet helps speed up re-connection
in the case that Nebula on either side did not shut down cleanly. This response can be abused as a way to discover if Nebula is running
on a host though. This option lets you configure if you want to send `recv_error` packets always, never, or only to private network remotes.
valid values: always, never, private
This setting is reloadable with SIGHUP.
We are currently testing changes for multiport (related to #497) that
use fields 6 and 7 in the protobuf. Reserved these fields so that when
we eventually open the PR we are backwards compatible with any future
changes.
* fix panic in handleInvalidCertificate
when HandleMonitorTick fires, the hostmap can be nil which causes a panic to occur when trying to clean up the hostmap in handleInvalidCertificate. This fix just stops the invalidation from continuing if the hostmap doesn't exist.
* removed conditional for disconnectInvalid in HandleDeletionTick
This restores the hostMap.QueryVpnIP block to how it looked before #370
was merged. I'm not sure why the patch from #370 wanted to continue on
if there was no match found in the hostmap, since there isn't anything
to do at that point (the tunnel has already been closed).
This was causing a crash because the handleInvalidCertificate check
expects the hostinfo to be passed in (but it is nil since there was no
hostinfo in the hostmap).
Fixes: #657
Wade Simmons