[tailscale] net: add SockTrace API #45

mihaip · 2023-02-03T20:06:08Z

Loosely inspired by nettrace/httptrace, allows functions to be called when sockets are read from or written to. The hooks are specified via the context (with a WithSockTrace function).

Only implemented for network sockets on POSIX systems.

Updates tailscale/corp#9230
Updates #58

Uses the hooks added by tailscale/go#45 to instrument the reads and writes on the major code paths that do network I/O in the client. For now just exposed as counters on a /v0/sockstats PeerAPI endpoint. Signed-off-by: Mihai Parparita <[email protected]>

bradfitz · 2023-02-03T20:49:15Z

src/net/sock_posix.go

+type SockTrace struct {
+	DidRead  func(int)
+	DidWrite func(int)
+}
+
+func WithSockTrace(ctx context.Context, trace *SockTrace) context.Context {
+	return context.WithValue(ctx, sockTraceKey{}, trace)
+}
+
+type sockTraceKey struct{}


so if you wanted to be lazy and bend the context.Context rules a bit, you can just use a string as the context.Value key, like:

"[tailscale.com]didread-func" and "[tailscale.com]didwrite-func" and then ditch these three symbols.

Then you could use it safely from the tailscaled side without build tags. Either way.

Was thinking that it should be something more type safe so that

we get an error if you build it with the wrong toolchain (as opposed to stats silently breaking)

it's a nicer API, and in theory could be upstreamed

But if you think there's ~0 chance that this could/should be upstreamed, happy to change it.

Uses the hooks added by tailscale/go#45 to instrument the reads and writes on the major code paths that do network I/O in the client. For now just exposed as counters on a /v0/sockstats PeerAPI endpoint. We also keep track of the current interface so that we can break out the stats by interface. Signed-off-by: Mihai Parparita <[email protected]>

Uses the hooks added by tailscale/go#45 to instrument the reads and writes on the major code paths that do network I/O in the client. The convention is to use "<package>.<type>:<label>" as the annotation for the responsible code path. For now just exposed as counters on a /v0/sockstats PeerAPI endpoint. We also keep track of the current interface so that we can break out the stats by interface. Updates tailscale/corp#9230 Updates #3363 Signed-off-by: Mihai Parparita <[email protected]>

Loosely inspired by nettrace/httptrace, allows functions to be called when sockets are read from or written to. The hooks are specified via the context (with a WithSockTrace function). Only implemented for network sockets on POSIX systems. Updates tailscale/corp#9230 Updates #58

Uses the hooks added by tailscale/go#45 to instrument the reads and writes on the major code paths that do network I/O in the client. The convention is to use "<package>.<type>:<label>" as the annotation for the responsible code path. For now just exposed as counters on a /v0/sockstats PeerAPI endpoint. We also keep track of the current interface so that we can break out the stats by interface. Updates tailscale/corp#9230 Updates #3363 Signed-off-by: Mihai Parparita <[email protected]>

Uses the hooks added by tailscale/go#45 to instrument the reads and writes on the major code paths that do network I/O in the client. The convention is to use "<package>.<type>:<label>" as the annotation for the responsible code path. Enabled on iOS, macOS and Android only, since mobile platforms are the ones we're most interested in, and we are less sensitive to any throughput degradation due to the per-I/O callback overhead (macOS is also enabled for ease of testing during development). For now just exposed as counters on a /v0/sockstats PeerAPI endpoint. We also keep track of the current interface so that we can break out the stats by interface. Updates tailscale/corp#9230 Updates #3363 Signed-off-by: Mihai Parparita <[email protected]>

Extends the hooks added by #45 to also expose when TCP sockets are created or closed (meant to allow TCP stats to be read from them). We don't do this for all socket types since stats are not available for UDP sockets, and they tend to be short-lived, thus invoking the hooks would be useless overhead. Also fixes read/write hooks to not count out-of-band data, since that's usually not sent over the wire. Updates tailscale/corp#9230 Updates #58

Extends the hooks added by #45 to also expose when TCP sockets are created or closed (meant to allow TCP stats to be read from them). We don't do this for all socket types since stats are not available for UDP sockets, and they tend to be short-lived, thus invoking the hooks would be useless overhead. Also fixes read/write hooks to not count out-of-band data, since that's usually not sent over the wire. Updates tailscale/corp#9230 Updates #58 Signed-off-by: Jenny Zhang <[email protected]> (Cherry-picked from db4dc90)

Extends the hooks added by #45 to also expose when TCP sockets are created or closed (meant to allow TCP stats to be read from them). We don't do this for all socket types since stats are not available for UDP sockets, and they tend to be short-lived, thus invoking the hooks would be useless overhead. Also fixes read/write hooks to not count out-of-band data, since that's usually not sent over the wire. Updates tailscale/corp#9230 Updates #58 Signed-off-by: Jenny Zhang <[email protected]> (Cherry-picked from db4dc90) (cherry picked from commit 51a96ad) (cherry picked from commit aff7d04)

Extends the hooks added by #45 to also expose when TCP sockets are created or closed (meant to allow TCP stats to be read from them). We don't do this for all socket types since stats are not available for UDP sockets, and they tend to be short-lived, thus invoking the hooks would be useless overhead. Also fixes read/write hooks to not count out-of-band data, since that's usually not sent over the wire. Updates tailscale/corp#9230 Updates #58 Signed-off-by: Jenny Zhang <[email protected]> (Cherry-picked from db4dc90) (cherry picked from commit 51a96ad) (cherry picked from commit aff7d04) Signed-off-by: Brad Fitzpatrick <[email protected]>

mihaip mentioned this pull request Feb 3, 2023

sockstats: instrument networking code paths tailscale/tailscale#7177

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bradfitz reviewed Feb 3, 2023

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mihaip force-pushed the mihaip/sock-trace branch from c473f4b to 4ab6a1b Compare February 27, 2023 22:19

mihaip changed the title ~~net: add SockTrace API~~ [tailscale] net: add SockTrace API Feb 27, 2023

mihaip marked this pull request as ready for review February 27, 2023 22:19

mihaip force-pushed the mihaip/sock-trace branch from 4ab6a1b to ec544e5 Compare February 27, 2023 23:52

mihaip mentioned this pull request Feb 28, 2023

patch: net: add socket read/write hooks #58

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mihaip force-pushed the mihaip/sock-trace branch from ec544e5 to 6234152 Compare February 28, 2023 00:08

bradfitz approved these changes Feb 28, 2023

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mihaip force-pushed the mihaip/sock-trace branch from 6234152 to b2969cb Compare February 28, 2023 00:19

mihaip merged commit fb11c0d into tailscale.go1.20 Feb 28, 2023

mihaip deleted the mihaip/sock-trace branch February 28, 2023 01:21

mihaip mentioned this pull request Mar 8, 2023

[tailscale] net: add TCP socket creation/close hooks to SockTrace API #59

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[tailscale] net: add SockTrace API #45

[tailscale] net: add SockTrace API #45

mihaip commented Feb 3, 2023 •

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bradfitz Feb 3, 2023

mihaip Feb 27, 2023

[tailscale] net: add SockTrace API #45

[tailscale] net: add SockTrace API #45

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mihaip commented Feb 3, 2023 •

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