dialSerial connects to a list of addresses in sequence. If a
timeout is specified, then each address gets an equal fraction of the
remaining time, with a magic constant (2 seconds) to prevent
"dial a million addresses" from allotting zero time to each.
Normally, net.Dial passes the DNS stub resolver's output to dialSerial.
If an error occurs (like destination/port unreachable), it quickly skips
to the next address, but a blackhole in the network will cause the
connection to hang until the timeout elapses. This is how UNIXy clients
traditionally behave, and is usually sufficient for non-broken networks.
The DualStack flag enables dialParallel, which implements Happy Eyeballs
by racing two dialSerial goroutines, giving the preferred family a
head start (300ms by default). This allows clients to avoid long
timeouts when the network blackholes IPv4 xor IPv6.
Fixes#8453Fixes#8455Fixes#8847
Change-Id: Ie415809c9226a1f7342b0217dcdd8f224ae19058
Reviewed-on: https://go-review.googlesource.com/8768
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This change fixes incorrect parsing of literal IP addresses in local
database when the addresses contain IPv6 zone identifiers, are in
dotted-decimal notation or in colon-hexadecimal notation with leading
zeros.
https://golang.org/cl/5851 already fixed the code path using getaddrinfo
via cgo. This change fixes the remaining non-cgo code path.
Fixes#8243.
Fixes#8996.
Change-Id: I48443611cbabed0d69667cc73911ba3de396fd44
Reviewed-on: https://go-review.googlesource.com/10306
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This change adds testHookLookIP to enable to inject DNS name to IP
address mappings for Happ{y,yish,ier} Eyeballs dial testing.
Change-Id: I8ac04a594e1e2bd77909528df0552889914a7790
Reviewed-on: https://go-review.googlesource.com/8399
Reviewed-by: Ian Lance Taylor <iant@golang.org>
