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| author | Brad Fitzpatrick <bradfitz@tailscale.com> | 2023-04-22 17:39:11 -0700 |
|---|---|---|
| committer | Brad Fitzpatrick <brad@danga.com> | 2023-04-22 17:53:39 -0700 |
| commit | 90ba26cea1b4ddea7314cebafc27d033bda1d772 (patch) | |
| tree | b4128cf972abdeed0d1fd8229dc36331220f6f4a | |
| parent | 7778d708a6a443dc03f8afc342f1b310b019b662 (diff) | |
| download | tailscale-90ba26cea1b4ddea7314cebafc27d033bda1d772.tar.xz tailscale-90ba26cea1b4ddea7314cebafc27d033bda1d772.zip | |
net/netcheck: fix crash when IPv6 kinda but not really works
Looks like on some systems there's an IPv6 address, but then opening
a IPv6 UDP socket fails later. Probably some firewall. Tolerate it
better and don't crash.
To repro: check the "udp6" to something like "udp7" (something that'll
fail) and run "go run ./cmd/tailscale netcheck" on a machine with
active IPv6. It used to crash and now it doesn't.
Fixes #7949
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
| -rw-r--r-- | net/netcheck/netcheck.go | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/net/netcheck/netcheck.go b/net/netcheck/netcheck.go index a61343ebe..603fa3a41 100644 --- a/net/netcheck/netcheck.go +++ b/net/netcheck/netcheck.go @@ -40,6 +40,7 @@ import ( "tailscale.com/types/logger" "tailscale.com/types/nettype" "tailscale.com/types/opt" + "tailscale.com/types/ptr" "tailscale.com/util/clientmetric" "tailscale.com/util/mak" ) @@ -943,6 +944,16 @@ func (c *Client) GetReport(ctx context.Context, dm *tailcfg.DERPMap) (_ *Report, go c.readPackets(ctx, u6) } } + + // If our interfaces.State suggested we have IPv6 support but then we + // failed to get an IPv6 sending socket (as in + // https://github.com/tailscale/tailscale/issues/7949), then change + // ifState.HaveV6 before we make a probe plan that involves sending IPv6 + // packets and thus assuming rs.pc6 is non-nil. + if rs.pc6 == nil { + ifState = ptr.To(*ifState) // shallow clone + ifState.HaveV6 = false + } } plan := makeProbePlan(dm, ifState, last) |