Scanning log lines is a frequent source of allocations.
Pre-allocate a re-usable buffer.
This still doesn't help when there are giant log lines.
Those will still be problematic from an iOS memory perspective.
For more on that, see https://github.com/tailscale/corp/issues/2423.
(For those who cannot follow that link, it is a discussion
of particular problematic types of log lines for
particular categories of customers. The "categories of customers"
part is the reason that it is a private issue.)
There is also a latent bug here. If we ever encounter
a log line longer than bufio.MaxScanTokenSize,
then bufio.Scan will return an error,
and we'll truncate the file and discard the rest of the log.
That's not good, but bufio.MaxScanTokenSize is really big,
so it probably doesn't matter much in practice now.
Unfortunately, it does prevent us from easily capping the potential
memory usage here, on pain of losing log entries.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Prior to Go 1.16, iOS used GOOS=darwin,
so we had to distinguish macOS from iOS during GOARCH.
We now require Go 1.16 in our go.mod, so we can simplify.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Now that we have the easier-to-parse go:build build tags,
it is straightforward to simplify them. Yay.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
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>
Allows FreeBSD to function as an exit node in the same way
that Windows and Tailscaled-on-MacOS do.
RELNOTE=FreeBSD can now function as an exit node.
Fixes https://github.com/tailscale/tailscale/issues/2498
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
Not even close to usable or well integrated yet, but submitting this before
it bitrots or I lose it.
Updates #1235
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This logs some basic statistics for UPnP, so that tailscale can better understand what routers
are being used and how to connect to them.
Signed-off-by: julianknodt <julianknodt@gmail.com>
This adds a PCP test to the IGD test server, by hardcoding in a few observed packets from
Denton's box.
Signed-off-by: julianknodt <julianknodt@gmail.com>
We want to use tsweb to format Prometheus-style metrics from
our temporary golang.org/x/net/http2 fork, but we don't want http2
to depend on the tailscale.com module to use the concrete type
tailscale.com/metrics.LabelMap. Instead, let a expvar.Map be used
instead of it's annotated sufficiently in its name.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
rsc.io/goversion is really expensive.
Running version.ReadExe on tailscaled on darwin
allocates 47k objects, almost 11mb.
All we want is the module info. For that, all we need to do
is scan through the binary looking for the magic start/end strings
and then grab the bytes in between them.
We can do that easily and quickly with nothing but a 64k buffer.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
And use dynamic port numbers in tests, as Linux on GitHub Actions and
Windows in general have things running on these ports.
Co-Author: Julian Knodt <julianknodt@gmail.com>
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Previously, we hashed the question and combined it with the original
txid which was useful when concurrent queries were multiplexed on a
single local source port. We encountered some situations where the DNS
server canonicalizes the question in the response (uppercase converted
to lowercase in this case), which resulted in responses that we couldn't
match to the original request due to hash mismatches. This includes a
new test to cover that situation.
Fixes#2597
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
Before we didn't detect it properly. Since Oracle Linux is diet centos,
we can just make the centos logic detect Oracle linux and everything
should be fine.
Signed-off-by: Christine Dodrill <xe@tailscale.com>
PCP handles external IPs by allowing the client to specify them in the packet, which is more
explicit than requiring 2 packets from PMP, so allow for future changes to add it in easily.
Signed-off-by: julianknodt <julianknodt@gmail.com>
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>
Prior to Tailscale 1.12 it detected UPnP on any port.
Starting with Tailscale 1.11.x, it stopped detecting UPnP on all ports.
Then start plumbing its discovered Location header port number to the
code that was assuming port 5000.
Fixes#2109
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This was the proximate cause of #2579.
#2582 is a deeper fix, but this will remain
as a footgun, so may as well fix it too.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
The index for every struct field or slice element and
the number of fields for the struct is unncessary.
The hashing of Go values is unambiguous because every type (except maps)
encodes in a parsable manner. So long as we know the type information,
we could theoretically decode every value (except for maps).
At a high level:
* numbers are encoded as fixed-width records according to precision.
* strings (and AppendTo output) are encoded with a fixed-width length,
followed by the contents of the buffer.
* slices are prefixed by a fixed-width length, followed by the encoding
of each value. So long as we know the type of each element, we could
theoretically decode each element.
* arrays are encoded just like slices, but elide the length
since it is determined from the Go type.
* maps are encoded first with a byte indicating whether it is a cycle.
If a cycle, it is followed by a fixed-width index for the pointer,
otherwise followed by the SHA-256 hash of its contents. The encoding of maps
is not decodeable, but a SHA-256 hash is sufficient to avoid ambiguities.
* interfaces are encoded first with a byte indicating whether it is nil.
If not nil, it is followed by a fixed-width index for the type,
and then the encoding for the underlying value. Having the type be encoded
first ensures that the value could theoretically be decoded next.
* pointers are encoded first with a byte indicating whether it is
1) nil, 2) a cycle, or 3) newly seen. If a cycle, it is followed by
a fixed-width index for the pointer. If newly seen, it is followed by
the encoding for the pointed-at value.
Removing unnecessary details speeds up hashing:
name old time/op new time/op delta
Hash-8 76.0µs ± 1% 55.8µs ± 2% -26.62% (p=0.000 n=10+10)
HashMapAcyclic-8 61.9µs ± 0% 62.0µs ± 0% ~ (p=0.666 n=9+9)
TailcfgNode-8 10.2µs ± 1% 7.5µs ± 1% -26.90% (p=0.000 n=10+9)
HashArray-8 1.07µs ± 1% 0.70µs ± 1% -34.67% (p=0.000 n=10+9)
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
For testing pfSense clients "behind" pfSense on Digital Ocean where
the main interface still exists. This is easier for debugging.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
