Commit Graph

79 Commits (9af7e8a0ffe480c07f6f013ce42f9ae3336ef9aa)

Author SHA1 Message Date
Matt Layher 8ab44b339e net/tstun: use unix.Ifreq type for Linux TAP interface configuration
Signed-off-by: Matt Layher <mdlayher@gmail.com>
3 years ago
Brad Fitzpatrick 833200da6f net/tstun: don't exec uname -r on Linux in TUN failure diagnostics
Fixes https://twitter.com/zekjur/status/1425557520513486848

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Brad Fitzpatrick e804ab29fd net/tstun: move TUN failure diagnostics to OS-specific files
Mostly so the Linux one can use Linux-specific stuff in package
syscall and not use os/exec for uname for portability.

But also it helps deps a tiny bit on iOS.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Josh Bleecher Snyder a5da4ed981 all: gofmt with Go 1.17
This adds "//go:build" lines and tidies up existing "// +build" lines.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Brad Fitzpatrick a729070252 net/tstun: add start of Linux TAP support, with DHCP+ARP server
Still very much a prototype (hard-coded IPs, etc) but should be
non-invasive enough to submit at this point and iterate from here.

Updates #2589

Co-Author: David Crawshaw <crawshaw@tailscale.com>
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
Josh Bleecher Snyder c2202cc27c net/tstun: use mono.Time
There's a call to Now once per packet.
Move to mono.Now.

Though the current implementation provides high precision,
we document it to be coarse, to preserve the ability
to switch to a coarse monotonic time later.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Josh Bleecher Snyder 1034b17bc7 net/tstun: buffer outbound channel
The handoff between tstun.Wrap's Read and poll methods
is one of the per-packet hotspots. It shows up in pprof.

Making outbound buffered increases throughput.

It is hard to measure exactly how much, because the numbers
are highly variable, but I'd estimate it at about 1%,
using the best observed max throughput across three runs.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Josh Bleecher Snyder 965dccd4fc net/tstun: buffer outbound channel
The handoff between tstun.Wrap's Read and poll methods
is one of the per-packet hotspots. It shows up in pprof.

Making outbound buffered increases throughput.

It is hard to measure exactly how much, because the numbers
are highly variable, but I'd estimate it at about 1%,
using the best observed max throughput across three runs.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Josh Bleecher Snyder 0ad92b89a6 net/tstun: fix data races
To remove some multi-case selects, we intentionally allowed
sends on closed channels (cc23049cd2).

However, we also introduced concurrent sends and closes,
which is a data race.

This commit fixes the data race. The mutexes here are uncontended,
and thus very cheap.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Josh Bleecher Snyder c35a832de6 net/tstun: add inner loop to poll
This avoids re-enqueuing to t.bufferConsumed,
which makes the code a bit clearer.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Josh Bleecher Snyder a4cc7b6d54 net/tstun: simplify code
Calculate whether the packet is injected directly,
rather than via an else branch.

Unify the exit paths. It is easier here than duplicating them.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
Josh Bleecher Snyder cc23049cd2 net/tstun: remove multi-case selects from hot code
Every TUN Read went through several multi-case selects.
We know from past experience with wireguard-go that these are slow
and cause scheduler churn.

The selects served two purposes: they separated errors from data and
gracefully handled shutdown. The first is fairly easy to replace by sending
errors and data over a single channel. The second, less so.

We considered a few approaches: Intricate webs of channels,
global condition variables. They all get ugly fast.

Instead, let's embrace the ugly and handle shutdown ungracefully.
It's horrible, but the horror is simple and localized.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
3 years ago
David Anderson df8a5d09c3 net/tstun: add a debug envvar to override tun MTU.
Signed-off-by: David Anderson <dave@natulte.net>
4 years ago
Brad Fitzpatrick a321c24667 go.mod: update netaddr
Involves minor IPSetBuilder.Set API change.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
Josh Bleecher Snyder 1ece91cede go.mod: upgrade wireguard-windows, de-fork wireguard-go
Pull in the latest version of wireguard-windows.

Switch to upstream wireguard-go.
This requires reverting all of our import paths.

Unfortunately, this has to happen at the same time.
The wireguard-go change is very low risk,
as that commit matches our fork almost exactly.
(The only changes are import paths, CI files, and a go.mod entry.)
So if there are issues as a result of this commit,
the first place to look is wireguard-windows changes.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
4 years ago
Josh Bleecher Snyder 25df067dd0 all: adapt to opaque netaddr types
This commit is a mishmash of automated edits using gofmt:

gofmt -r 'netaddr.IPPort{IP: a, Port: b} -> netaddr.IPPortFrom(a, b)' -w .
gofmt -r 'netaddr.IPPrefix{IP: a, Port: b} -> netaddr.IPPrefixFrom(a, b)' -w .

gofmt -r 'a.IP.Is4 -> a.IP().Is4' -w .
gofmt -r 'a.IP.As16 -> a.IP().As16' -w .
gofmt -r 'a.IP.Is6 -> a.IP().Is6' -w .
gofmt -r 'a.IP.As4 -> a.IP().As4' -w .
gofmt -r 'a.IP.String -> a.IP().String' -w .

And regexps:

\w*(.*)\.Port = (.*)  ->  $1 = $1.WithPort($2)
\w*(.*)\.IP = (.*)  ->  $1 = $1.WithIP($2)

And lots of manual fixups.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
4 years ago
Brad Fitzpatrick 7f2eb1d87a net/tstun: fix TUN log spam when ACLs drop a packet
Whenever we dropped a packet due to ACLs, wireguard-go was logging:

Failed to write packet to TUN device: packet dropped by filter

Instead, just lie to wireguard-go and pretend everything is okay.

Fixes #1229

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
Josh Bleecher Snyder 42c8b9ad53 net/tstun: remove unnecessary break statement
Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
4 years ago
Josh Bleecher Snyder 99705aa6b7 net/tstun: split TUN events channel into up/down and MTU
We had a long-standing bug in which our TUN events channel
was being received from simultaneously in two places.

The first is wireguard-go.

At wgengine/userspace.go:366, we pass e.tundev to wireguard-go,
which starts a goroutine (RoutineTUNEventReader)
that receives from that channel and uses events to adjust the MTU
and bring the device up/down.

At wgengine/userspace.go:374, we launch a goroutine that
receives from e.tundev, logs MTU changes, and triggers
state updates when up/down changes occur.

Events were getting delivered haphazardly between the two of them.

We don't really want wireguard-go to receive the up/down events;
we control the state of the device explicitly by calling device.Up.
And the userspace.go loop MTU logging duplicates logging that
wireguard-go does when it received MTU updates.

So this change splits the single TUN events channel into up/down
and other (aka MTU), and sends them to the parties that ought
to receive them.

I'm actually a bit surprised that this hasn't caused more visible trouble.
If a down event went to wireguard-go but the subsequent up event
went to userspace.go, we could end up with the wireguard-go device disappearing.

I believe that this may also (somewhat accidentally) be a fix for #1790.

Signed-off-by: Josh Bleecher Snyder <josharian@gmail.com>
4 years ago
Avery Pennarun a92b9647c5 wgengine/bench: speed test for channels, sockets, and wireguard-go.
This tries to generate traffic at a rate that will saturate the
receiver, without overdoing it, even in the event of packet loss. It's
unrealistically more aggressive than TCP (which will back off quickly
in case of packet loss) but less silly than a blind test that just
generates packets as fast as it can (which can cause all the CPU to be
absorbed by the transmitter, giving an incorrect impression of how much
capacity the total system has).

Initial indications are that a syscall about every 10 packets (TCP bulk
delivery) is roughly the same speed as sending every packet through a
channel. A syscall per packet is about 5x-10x slower than that.

The whole tailscale wireguard-go + magicsock + packet filter
combination is about 4x slower again, which is better than I thought
we'd do, but probably has room for improvement.

Note that in "full" tailscale, there is also a tundev read/write for
every packet, effectively doubling the syscall overhead per packet.

Given these numbers, it seems like read/write syscalls are only 25-40%
of the total CPU time used in tailscale proper, so we do have
significant non-syscall optimization work to do too.

Sample output:

$ GOMAXPROCS=2 go test -bench . -benchtime 5s ./cmd/tailbench
goos: linux
goarch: amd64
pkg: tailscale.com/cmd/tailbench
cpu: Intel(R) Core(TM) i7-4785T CPU @ 2.20GHz
BenchmarkTrivialNoAlloc/32-2         	56340248	        93.85 ns/op	 340.98 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkTrivialNoAlloc/124-2        	57527490	        99.27 ns/op	1249.10 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkTrivialNoAlloc/1024-2       	52537773	       111.3 ns/op	9200.39 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkTrivial/32-2                	41878063	       135.6 ns/op	 236.04 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkTrivial/124-2               	41270439	       138.4 ns/op	 896.02 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkTrivial/1024-2              	36337252	       154.3 ns/op	6635.30 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkBlockingChannel/32-2           12171654	       494.3 ns/op	  64.74 MB/s	         0 %lost	    1791 B/op	       0 allocs/op
BenchmarkBlockingChannel/124-2          12149956	       507.8 ns/op	 244.17 MB/s	         0 %lost	    1792 B/op	       1 allocs/op
BenchmarkBlockingChannel/1024-2         11034754	       528.8 ns/op	1936.42 MB/s	         0 %lost	    1792 B/op	       1 allocs/op
BenchmarkNonlockingChannel/32-2          8960622	      2195 ns/op	  14.58 MB/s	         8.825 %lost	    1792 B/op	       1 allocs/op
BenchmarkNonlockingChannel/124-2         3014614	      2224 ns/op	  55.75 MB/s	        11.18 %lost	    1792 B/op	       1 allocs/op
BenchmarkNonlockingChannel/1024-2        3234915	      1688 ns/op	 606.53 MB/s	         3.765 %lost	    1792 B/op	       1 allocs/op
BenchmarkDoubleChannel/32-2          	 8457559	       764.1 ns/op	  41.88 MB/s	         5.945 %lost	    1792 B/op	       1 allocs/op
BenchmarkDoubleChannel/124-2         	 5497726	      1030 ns/op	 120.38 MB/s	        12.14 %lost	    1792 B/op	       1 allocs/op
BenchmarkDoubleChannel/1024-2        	 7985656	      1360 ns/op	 752.86 MB/s	        13.57 %lost	    1792 B/op	       1 allocs/op
BenchmarkUDP/32-2                    	 1652134	      3695 ns/op	   8.66 MB/s	         0 %lost	     176 B/op	       3 allocs/op
BenchmarkUDP/124-2                   	 1621024	      3765 ns/op	  32.94 MB/s	         0 %lost	     176 B/op	       3 allocs/op
BenchmarkUDP/1024-2                  	 1553750	      3825 ns/op	 267.72 MB/s	         0 %lost	     176 B/op	       3 allocs/op
BenchmarkTCP/32-2                    	11056336	       503.2 ns/op	  63.60 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkTCP/124-2                   	11074869	       533.7 ns/op	 232.32 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkTCP/1024-2                  	 8934968	       671.4 ns/op	1525.20 MB/s	         0 %lost	       0 B/op	       0 allocs/op
BenchmarkWireGuardTest/32-2          	 1403702	      4547 ns/op	   7.04 MB/s	        14.37 %lost	     467 B/op	       3 allocs/op
BenchmarkWireGuardTest/124-2         	  780645	      7927 ns/op	  15.64 MB/s	         1.537 %lost	     420 B/op	       3 allocs/op
BenchmarkWireGuardTest/1024-2        	  512671	     11791 ns/op	  86.85 MB/s	         0.5206 %lost	     411 B/op	       3 allocs/op
PASS
ok  	tailscale.com/wgengine/bench	195.724s

Updates #414.

Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>
4 years ago
Brad Fitzpatrick 939861773d net/tstun: accept peerapi connections through the filter
Fixes tailscale/corp#1545

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
David Anderson bc4381447f net/tstun: return the real interface name at device creation.
This is usually the same as the requested interface, but on some
unixes can vary based on device number allocation, and on Windows
it's the GUID instead of the pretty name, since everything relating
to configuration wants the GUID.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
Brad Fitzpatrick 41e4e02e57 net/{packet,tstun}: send peerapi port in TSMP pongs
For discovery when an explicit hostname/IP is known. We'll still
also send it via control for finding peers by a list.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
4 years ago
David Anderson 25e0bb0a4e net/tstun: rename wrap_windows.go to tun_windows.go.
The code has nothing to do with wrapping, it's windows-specific
driver initialization code.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 22d53fe784 net/tstun: document exported function.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 016de16b2e net/tstun: rename TUN to Wrapper.
The tstun packagen contains both constructors for generic tun
Devices, and a wrapper that provides additional functionality.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 82ab7972f4 net/tstun: rename NewFakeTUN to NewFake.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 588b70f468 net/tstun: merge in wgengine/tstun.
Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago
David Anderson 018200aeba net/tstun: rename from net/tun.
We depend on wireguard-go/tun, identical leaf packages can be
confusing in code.

Signed-off-by: David Anderson <danderson@tailscale.com>
4 years ago