ResolveTCPAddr, ResolveUDPAddr, and ResolveIPAddr return at most one
address. When given a name like "golang.org" to resolve that might
have more than 1 address, the net package has historically preferred
IPv4 addresses, with the assumption that many users don't yet have
IPv6 connectivity and randomly selecting between an IPv4 address and
an IPv6 address at runtime wouldn't be a good experience for IPv4-only
users.
In CL 45088 (78cf0e56) I modified the resolution of the
unspecified/empty address to internally resolve to both IPv6 "::" and
0.0.0.0 to fix issue #18806.
That code has 3 other callers I hadn't considered, though: the
Resolve*Addr functions. Since they preferred IPv4, any Resolve*Addr of
"[::]:port" or "::" (for ResolveIPAddr) would internally resolve both
"::" and 0.0.0.0 and then prefer 0.0.0.0, even though the user was
looking up an IPv6 literal.
Add tests and fix it, not by undoing the fix to #18806 but by
selecting the preference function for Resolve*Addr more explicitly: we
still prefer IPv4, but if the address being looked up was an IPv6
literal, prefer IPv6.
The tests are skipped on machines without IPv6.
Fixes#20911
Change-Id: Ib7036cc43182ae4118cd1390c254e17c04a251a3
Reviewed-on: https://go-review.googlesource.com/47554
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
This change simplifies the documentation on methods of UDPConn and
adds a reference to golang.org/x/net/{ipv4,ipv6} packages to the
documentation on {Read,Write}MsgUDP methods.
Change-Id: I425a8d81bc46b6579aa9f89faa4982bb86b40f24
Reviewed-on: https://go-review.googlesource.com/44912
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change clarifies the documentation on
Resolve{TCP,UDP,IP,Unix}Addr to avoid unnecessary confusion about how
the arguments are used to make end point addresses.
Also replaces "name" or "hostname" with "host name" when the term
implies the use of DNS.
Updates #17613.
Change-Id: Id6be87fe2e4666eecd5b92f18ad8b9a6c50a2bd6
Reviewed-on: https://go-review.googlesource.com/34879
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change clarifies the documentation on
Listen{TCP,UDP,MulticastUDP,IP,Unix,Unixgram} to avoid unnecessary
confusion about how the arguments for the connection setup functions
are used to make connections.
Change-Id: Ie269453ef49ec2db893391dc3ed2f7b641c14249
Reviewed-on: https://go-review.googlesource.com/34878
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change clarifies the documentation on Dial{TCP,UDP,IP,Unix} to
avoid unnecessary confusion about how the arguments for the connection
setup functions are used to make connections.
Change-Id: I2e378182948fbe221f6ae786ab55e77ae90c3f3b
Reviewed-on: https://go-review.googlesource.com/34877
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change makes {TCP,UDP,IP,Unix}Conn types compliant of
syscall.Conn interface and adds type rawConn as an implementation of
syscall.RawConn interface.
By this change, the long-standing issues regarding unsupported socket
options and system calls can be solved partly and the broken x/net
packages due to https://go-review.googlesource.com/36799 can be
repaired.
Fixes#3661.
Updates #9661.
Updates #19051.
Updates #19435.
Change-Id: Ic996b040418b54f6d043bc70591789d5a5b23270
Reviewed-on: https://go-review.googlesource.com/37039
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
In general, these functions cannot behave correctly when given a
hostname, because a hostname may represent multiple IP addresses, and
first(isIPv4) chooses at most one.
Updates #9334
Change-Id: Icfb629f84af4d976476385a3071270253c0000b1
Reviewed-on: https://go-review.googlesource.com/31931
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The new Resolver type (a struct) has 9 Lookup methods, all taking a
context.Context.
There's now a new DefaultResolver global, like http's
DefaultTransport and DefaultClient.
net.Dialer now has an optional Resolver field to set the Resolver.
This also does finishes some resolver cleanup internally, deleting
lookupIPMerge and renaming lookupIPContext into Resolver.LookupIPAddr.
The Resolver currently doesn't let you tweak much, but it's a struct
specifically so we can add knobs in the future. Currently I just added
a bool to force the pure Go resolver. In the future we could let
people provide an interface to implement the methods, or add a Timeout
time.Duration, which would wrap all provided contexts in a
context.WithTimeout.
Fixes#16672
Change-Id: I7ba1f886704f06def7b6b5c4da9809db51bc1495
Reviewed-on: https://go-review.googlesource.com/29440
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change consolidates functions and methods related to UDPAddr and
UDPConn for maintenance purpose, especially for documentation.
The followup changes will update comments and examples.
Updates #10624.
Change-Id: Idfe9be8ea46ade1111b0ae176862b2048eafc7be
Reviewed-on: https://go-review.googlesource.com/20120
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.
Go policy has been single space after periods in comments for some time.
The copyright header template at:
https://golang.org/doc/contribute.html#copyright
also uses a single space.
Make them all consistent.
Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Remove the "netaddr" type, which ambiguously represented either one
address, or a list of addresses. Instead, use "addrList" wherever
multiple addresses are supported.
The "first" method returns the first address matching some condition
(e.g. "is it IPv4?"), primarily to support legacy code that can't handle
multiple addresses.
The "partition" method splits an addrList into two categories, as
defined by some strategy function. This is useful for implementing
Happy Eyeballs, and similar two-channel algorithms.
Finally, internetAddrList (formerly resolveInternetAddr) no longer
mangles the ordering defined by getaddrinfo. In the future, this may
be used by a sequential Dial implementation.
Updates #8453, #8455.
Change-Id: I7375f4c34481580ab40e31d33002a4073a0474f3
Reviewed-on: https://go-review.googlesource.com/8360
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This change consolidates test helpers that test platform capabilities.
testNetwork, testAddress and testListenArgs report whether given
ariguments are testable on the current platform configuration to
mitigate to receive weird test results.
Change-Id: Ie1ed568a1f9cc50f3155945ea01562904bc2c389
Reviewed-on: https://go-review.googlesource.com/8076
Reviewed-by: Ian Lance Taylor <iant@golang.org>
