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51 Commits

Author SHA1 Message Date
Ian Lance Taylor b4652028d4 net: consistently document deadline handling
After CL 228645 some mentions of the Deadline methods referred
to the Timeout method, and some to os.ErrDeadlineExceeded.
Stop referring to the Timeout method, to encourage ErrDeadlineExceeded.

For #31449

Change-Id: I27b8ff34f31798f38b06437546886af8cce98ca4
Reviewed-on: https://go-review.googlesource.com/c/go/+/239705
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-06-24 22:40:11 +00:00
Ian Lance Taylor d422f54619 os, net: define and use os.ErrDeadlineExceeded
If an I/O operation fails because a deadline was exceeded,
return os.ErrDeadlineExceeded. We used to return poll.ErrTimeout,
an internal error, and told users to check the Timeout method.
However, there are other errors with a Timeout method that returns true,
notably syscall.ETIMEDOUT which is returned for a keep-alive timeout.
Checking errors.Is(err, os.ErrDeadlineExceeded) should permit code
to reliably tell why it failed.

This change does not affect the handling of net.Dialer.Deadline,
nor does it change the handling of net.DialContext when the context
deadline is exceeded. Those cases continue to return an error
reported as "i/o timeout" for which Timeout is true, but that error
is not os.ErrDeadlineExceeded.

Fixes #31449

Change-Id: I0323f42e944324c6f2578f00c3ac90c24fe81177
Reviewed-on: https://go-review.googlesource.com/c/go/+/228645
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
2020-04-25 00:26:48 +00:00
Yasser Abdolmaleki cbaa666682 net: document *OpError.Err must not be nil
The point of *net.OpError is to add details to an underlying lower
level error. It makes no sense to have an OpError without an Err and
a nil *OpError.Err will cause *OpError.Error() method to panic.

Fixes #33007

Change-Id: If4fb2501e02dad110a095b73e18c47312ffa6015
Reviewed-on: https://go-review.googlesource.com/c/go/+/187677
Reviewed-by: Rob Pike <r@golang.org>
2020-01-19 02:25:54 +00:00
Ian Lance Taylor 8b058cfbce net: document that a keep-alive failure also returns a timeout
Updates #31449

Change-Id: I76490c5e83eb2f7ba529b387a57ba088428aece5
Reviewed-on: https://go-review.googlesource.com/c/go/+/189757
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
2019-08-11 15:44:08 +00:00
Damien Neil 0e54d28ff7 all: remove os.ErrTimeout
It is unclear whether the current definition of os.IsTimeout is
desirable or not. Drop ErrTimeout for now so we can consider adding it
(or some other error) in a future release with a corrected definition.

Fixes #33411

Change-Id: I8b880da7d22afc343a08339eb5f0efd1075ecafe
Reviewed-on: https://go-review.googlesource.com/c/go/+/188758
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-08-02 17:57:18 +00:00
Damien Neil ea8b0acdac all: remove os.ErrTemporary
As discussed in
https://github.com/golang/go/issues/32463#issuecomment-506833421
the classification of deadline-based timeouts as "temporary" errors is a
historical accident. I/O timeouts used to be duration-based, so they
really were temporary--retrying a timed-out operation could succeed. Now
that they're deadline-based, timeouts aren't temporary unless you reset
the deadline.

Drop ErrTemporary from Go 1.13, since its definition is wrong. We'll
consider putting it back in Go 1.14 with a clear definition and
deprecate net.OpError.Temporary.

Fixes #32463

Change-Id: I70cda664590d8872541e17409a5780da76920891
Reviewed-on: https://go-review.googlesource.com/c/go/+/188398
Reviewed-by: Jonathan Amsterdam <jba@google.com>
2019-08-01 15:39:45 +00:00
Damien Neil 170b8b4b12 all: add Unwrap and Is methods to various error types
Add Unwrap methods to types which wrap an underlying error:

  "encodinc/csv".ParseError
  "encoding/json".MarshalerError
  "net/http".transportReadFromServerError
  "net".OpError
  "net".DNSConfigError
  "net/url".Error
  "os/exec".Error
  "signal/internal/pty".PtyError
  "text/template".ExecError

Add os.ErrTemporary. A case could be made for putting this error
value in package net, since no exported error types in package os
include a Temporary method. However, syscall errors returned from
the os package do include this method.

Add Is methods to error types with a Timeout or Temporary method,
making errors.Is(err, os.Err{Timeout,Temporary}) equivalent to
testing the corresponding method:

  "context".DeadlineExceeded
  "internal/poll".TimeoutError
  "net".adrinfoErrno
  "net".OpError
  "net".DNSError
  "net/http".httpError
  "net/http".tlsHandshakeTimeoutError
  "net/pipe".timeoutError
  "net/url".Error

Updates #30322
Updates #29934

Change-Id: I409fb20c072ea39116ebfb8c7534d493483870dc
Reviewed-on: https://go-review.googlesource.com/c/go/+/170037
Run-TryBot: Damien Neil <dneil@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
2019-05-04 16:14:12 +00:00
Shubham Sharma fac3b5d05e net: add IsNotFound field to DNSError
This adds the ability to determine if a lookup error was
due to a non-existent hostname. Previously users needed
to do string matching on the DNSError.Err value.

Fixes #28635

Change-Id: If4bd3ad32cbc2db5614f2c6b72e0a9161d813efa
Reviewed-on: https://go-review.googlesource.com/c/go/+/168597
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-04-23 14:11:33 +00:00
Josh Bleecher Snyder 5781df421e all: s/cancelation/cancellation/
Though there is variation in the spelling of canceled,
cancellation is always spelled with a double l.

Reference: https://www.grammarly.com/blog/canceled-vs-cancelled/

Change-Id: I240f1a297776c8e27e74f3eca566d2bc4c856f2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/170060
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-04-16 20:27:15 +00:00
Matt Layher 501632339f net: add missing period in conn.File documentation
Change-Id: Ie873d7ed595c91cee4c1aa6c22fa44b61b6190ff
Reviewed-on: https://go-review.googlesource.com/c/go/+/169138
Run-TryBot: Matt Layher <mdlayher@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2019-03-25 18:16:51 +00:00
Brad Fitzpatrick 80fe2e6e37 net: lazily look up the listenerBacklog value on first use
Don't open files or do sysctls in init.

Updates #26775

Change-Id: I017bed6c24ef1e4bc30040120349fb779f203225
Reviewed-on: https://go-review.googlesource.com/127655
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-08-21 04:39:22 +00:00
Ian Lance Taylor b749845067 net: limit concurrent threads to limit on file descriptors
At least on Darwin, if getaddrinfo can't open a file descriptor it
returns EAI_NONAME ("no such host") rather than a meaningful error.
Limit the number of concurrent getaddrinfo calls to the number of file
descriptors we can open, to make that meaningless error less likely.

We don't apply the same limit to Go lookups, because for that we will
return a meaningful "too many open files" error.

Fixes #25694

Change-Id: I601857190aeb64f11e22b4a834c1c6a722a0788d
Reviewed-on: https://go-review.googlesource.com/121176
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-06-27 16:59:22 +00:00
Richard Musiol ef9217e7bd net: add js/wasm architecture
This commit adds the js/wasm architecture to the net package.
The net package is not supported by js/wasm, but a simple fake
networking is available so tests of other packages that require
basic TCP sockets can pass. The tests of the net package itself
are mostly disabled.

Updates #18892

Change-Id: Id287200c39f0a3e23d20ef17260ca15ccdcca032
Reviewed-on: https://go-review.googlesource.com/109995
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-06-04 16:01:50 +00:00
Ian Lance Taylor 7f6105f138 net, syscall: make ECONNRESET/ECONNABORTED only temporary for Accept
Updates #6163
Fixes #24808

Change-Id: I4f5c686ebf60f72f71f566199ee3e946076202bb
Reviewed-on: https://go-review.googlesource.com/110439
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-01 14:50:33 +00:00
Michael Fraenkel 60e3ebb9cb net: calling File leaves the socket in nonblocking mode
On Unix systems, the underlying socket is no longer forced into blocking
mode.

Fixes #24942

Change-Id: I3e0c503c72df0844e30a63af298691dedacd1f46
Reviewed-on: https://go-review.googlesource.com/108297
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-04-19 23:33:09 +00:00
Mansour Rahimi 79fe895112 net: fix UDPConn readers to return truncated payload size instead of 0
Calling UDPConn readers (Read, ReadFrom, ReadMsgUDP) to read part of
datagram returns error (in Windows), mentioning there is more data
available, and 0 as size of read data, even though part of data is
already read.

This fix makes UDPConn readers to return truncated payload size,
even there is error due more data available to read.

Fixes #14074
Updates #18056

Change-Id: Id7eec7f544dd759b2d970fa2561eef2937ec4662
Reviewed-on: https://go-review.googlesource.com/92475
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
2018-02-21 10:40:03 +00:00
Ian Lance Taylor a9410281c2 net: calling File disables the SetDeadline methods
This essentially applies https://golang.org/cl/81636 to the net package.

The full truth seems too complicated to write in this method's doc, so
I'm going with a simple half truth.

The full truth is that File returns the descriptor in blocking mode,
because that is historically how it worked, and existing programs
would be surprised if the descriptor is suddenly non-blocking. On Unix
systems whether a socket is non-blocking or not is a property of the
underlying file description, not of a particular file descriptor, so
changing the returned descriptor to blocking mode also changes the
existing socket to blocking mode. Blocking mode works fine, althoug I/O
operations now take up a thread. SetDeadline and friends rely on the
runtime poller, and the runtime poller only works if the descriptor is
non-blocking. So it's correct that calling File disables SetDeadline.
The other half of the truth is that if the program is willing to work
with a non-blocking descriptor, it could call
syscall.SetNonblock(f.Fd(), true) to change the descriptor, and
the original socket, to non-blocking mode. At that point SetDeadline
would start working again. I tried to write that in a way that is
short and comprehensible but failed. Since we now have the RawConn
approach to frobbing the descriptor, and hopefully most people can use
that rather than calling File, I decided to punt.

Updates #22934
Fixes #21862

Change-Id: If269da762f6f5a88c334e7b6d6f3998f7e10b11e
Reviewed-on: https://go-review.googlesource.com/82915
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-12-08 19:45:44 +00:00
Mikio Hara 6694a6888b net: delay IP protocol stack-snooping system calls
This change delays IP protocol stack-snooping system calls until the
start of connection setup for the better experience with some system
call auditing, such as seccomp on Linux. See #16789 for examples.

Also updates the documentation on favoriteAddrFamily, which is the
owner of stack-snooping system calls.

Fixes #16789.

Change-Id: I4af27bc1ed06ffb1f657b6f6381c328c1f41c66c
Reviewed-on: https://go-review.googlesource.com/40750
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-04-15 22:22:09 +00:00
Brad Fitzpatrick 6983b9a579 net, net/http: adjust time-in-past constant even earlier
The aLongTimeAgo time value in net and net/http is used to cancel
in-flight read and writes. It was set to time.Unix(233431200, 0)
which seemed like far enough in the past.

But Raspberry Pis, lacking a real time clock, had to spoil the fun and
boot in 1970 at the Unix epoch time, breaking assumptions in net and
net/http.

So change aLongTimeAgo to time.Unix(1, 0), which seems like the
earliest safe value. I don't trust subsecond values on all operating
systems, and I don't trust the Unix zero time. The Raspberry Pis do
advance their clock at least. And the reported problem was that Hijack
on a ResponseWriter hung forever, waiting for the connection read
operation to finish. So now, even if kernel + userspace boots in under
a second (unlikely), the Hijack will just have to wait for up to a
second.

Fixes #19747

Change-Id: Id59430de2e7b5b5117d4903a788863e9d344e53a
Reviewed-on: https://go-review.googlesource.com/38785
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2017-03-29 17:18:13 +00:00
Ian Lance Taylor 3792db5183 net: refactor poller into new internal/poll package
This will make it possible to use the poller with the os package.

This is a lot of code movement but the behavior is intended to be
unchanged.

Update #6817.
Update #7903.
Update #15021.
Update #18507.

Change-Id: I1413685928017c32df5654ded73a2643820977ae
Reviewed-on: https://go-review.googlesource.com/36799
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2017-02-13 18:36:28 +00:00
Joe Tsai 7e455163de net: update documentation on Conn and PacketConn
Fixes #17982

Change-Id: I4884a6b57905420ac0e37210c411de98c582de1d
Reviewed-on: https://go-review.googlesource.com/33473
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-11-26 05:01:32 +00:00
Russ Cox 866e01457f net: apply tcp4/tcp6 restrictions to literals in ResolveTCPAddr
The restrictions were already being applied to the IP addresses
received from the host resolver. Apply the same restrictions to
literal IP addresses not passed to the host resolver.

For example, ResolveTCPAddr("tcp4", "[2001:db8::1]:http") used
to succeed and now does not (that's not an IPv4 address).

Perhaps a bit surprisingly,
ResolveTCPAddr("tcp4", "[::ffff:127.0.0.1]:http") succeeds,
behaving identically to ResolveTCPAddr("tcp4", "127.0.0.1:http"), and
ResolveTCPAddr("tcp6", "[::ffff:127.0.0.1]:http") fails,
behaving identically to ResolveTCPAddr("tcp6", "127.0.0.1:http").
Even so, it seems right to match (by reusing) the existing filtering
as applied to addresses resolved by the host C library.
If anyone can make a strong argument for changing the filtering
of IPv4-inside-IPv6 addresses, the fix can be applied to all
the code paths in a separate CL.

Fixes #14037.

Change-Id: I690dfdcbe93d730e11e00ea387fa7484cd524341
Reviewed-on: https://go-review.googlesource.com/32100
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-11-11 17:07:07 +00:00
Mikio Hara 9575c58064 net: use IPv4 reserved address blocks for documentation
Updates #15228.

Change-Id: Iefdffa146703ee1c04afc2b71d9de1f0a0811f86
Reviewed-on: https://go-review.googlesource.com/32146
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-28 22:20:52 +00:00
Russ Cox c01c1d4215 net: add examples to Addr definition
Fixes #16014.

Change-Id: I68b096df7924a3258e940c4d94ec5d06f5bdfcbb
Reviewed-on: https://go-review.googlesource.com/32097
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-27 17:55:58 +00:00
Brad Fitzpatrick 5f36e9a306 net: clarify that Conn deadlines also affect currently-blocked I/O
All implementations have always implemented this behavior, it's
tested, and it's depended on by other packages. (notably, by net/http)

The one exception is Plan 9 which doesn't support I/O deadlines at all
(tracked in #11932). As a result, a bunch of tests fail on plan9
(#7237). But once Plan 9 adds I/O deadline support, it'll also need
this behavior.

Change-Id: Idb71767f0c99279c66dce29f7bdc78ef467e47aa
Reviewed-on: https://go-review.googlesource.com/30164
Reviewed-by: Sam Whited <sam@samwhited.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-03 17:47:08 +00:00
Brad Fitzpatrick 8e69d43b32 net: add Buffers type, do writev on unix
No fast path currently for solaris, windows, nacl, plan9.

Fixes #13451

Change-Id: I24b3233a2e3a57fc6445e276a5c0d7b097884007
Reviewed-on: https://go-review.googlesource.com/29951
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-29 20:33:45 +00:00
Mikio Hara 495e3c60aa net: use IPv4/IPv6 reserved address blocks for documentation
Also replaces google.com with golang.org in package documentation.

Updates #15228.

Change-Id: I554fa960878fa44557a522635ed412d8d7548d3f
Reviewed-on: https://go-review.googlesource.com/23126
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-05-17 04:02:11 +00:00
Brad Fitzpatrick b6b4004d5a net: context plumbing, add Dialer.DialContext
For #12580 (http.Transport tracing/analytics)
Updates #13021

Change-Id: I126e494a7bd872e42c388ecb58499ecbf0f014cc
Reviewed-on: https://go-review.googlesource.com/22101
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
2016-04-15 22:48:12 +00:00
Mikio Hara 790053b25e net: filter destination addresses when source address is specified
This change filters out destination addresses by address family when
source address is specified to avoid running Dial operation with wrong
addressing scopes.

Fixes #11837.

Change-Id: I10b7a1fa325add2cd8ed58f105d527700a10d342
Reviewed-on: https://go-review.googlesource.com/20586
Reviewed-by: Paul Marks <pmarks@google.com>
2016-03-16 03:17:56 +00:00
Brad Fitzpatrick 5fea2ccc77 all: single space after period.
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.

This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:

$ perl -i -npe 's,^(\s*// .+[a-z]\.)  +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.)  +([A-Z])')
$ go test go/doc -update

Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-02 00:13:47 +00:00
Brad Fitzpatrick 24a83d3545 net: add Dialer.Cancel to cancel pending dials
Dialer.Cancel is a new optional <-chan struct{} channel whose closure
indicates that the dial should be canceled. It is compatible with the
x/net/context and http.Request.Cancel types.

Tested by hand with:

package main

    import (
            "log"
            "net"
            "time"
    )

    func main() {
            log.Printf("start.")
            var d net.Dialer
            cancel := make(chan struct{})
            time.AfterFunc(2*time.Second, func() {
                    log.Printf("timeout firing")
                    close(cancel)
            })
            d.Cancel = cancel
            c, err := d.Dial("tcp", "192.168.0.1:22")
            if err != nil {
                    log.Print(err)
                    return
            }
            log.Fatalf("unexpected connect: %v", c)
    }

Which says:

    2015/12/14 22:24:58 start.
    2015/12/14 22:25:00 timeout firing
    2015/12/14 22:25:00 dial tcp 192.168.0.1:22: operation was canceled

Fixes #11225

Change-Id: I2ef39e3a540e29fe6bfec03ab7a629a6b187fcb3
Reviewed-on: https://go-review.googlesource.com/17821
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-12-15 21:15:15 +00:00
Brad Fitzpatrick 19d262ffdf net: remove named parameters in Listener.Accept doc signature
They added no value.

Change-Id: I9e690379d2dfd983266de0ea5231f2b57c8b1517
Reviewed-on: https://go-review.googlesource.com/14568
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-09-15 04:07:24 +00:00
Dan Peterson ced0646fe5 net: make DNSError.Temporary return true on SERVFAIL
Fixes #8434

Change-Id: I323222b4160f3aba35cac1de7f6df93c524b72ec
Reviewed-on: https://go-review.googlesource.com/14169
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-09-04 17:53:54 +00:00
Russ Cox b711f5ad8f net: document GODEBUG=netdns=xxx settings
Fixes #12191.

Change-Id: I5c7659ccb0566dad3613041d9e76be87ceacae61
Reviewed-on: https://go-review.googlesource.com/13700
Reviewed-by: Rob Pike <r@golang.org>
2015-08-19 04:08:34 +00:00
Brad Fitzpatrick b615ad8fd5 net: add mechanisms to force go or cgo lookup, and to debug default strategy
GODEBUG=netdns=1 prints a one-time strategy decision. (cgo or go DNS lookups)
GODEBUG=netdns=2 prints the per-lookup strategy as a function of the hostname.

The new "netcgo" build tag forces cgo DNS lookups.

GODEBUG=netdns=go (or existing build tag "netgo") forces Go DNS resolution.
GODEBUG=netdns=cgo (or new build tag "netcgo") forces libc DNS resolution.

Options can be combined with e.g. GODEBUG=netdns=go+1 or GODEBUG=netdns=2+cgo.

Fixes #11322
Fixes #11450

Change-Id: I7a67e9f759fd0a02320e7803f9ded1638b19e861
Reviewed-on: https://go-review.googlesource.com/11584
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-09 22:19:41 +00:00
Paul Marks 0d8366e2d6 net: add sequential and RFC 6555-compliant TCP dialing.
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 #8453
Fixes #8455
Fixes #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>
2015-06-16 02:38:21 +00:00
Mikio Hara 055ecb7be5 net: fix inconsistent errors
These a series of changes fix inconsistent errors on the package net
APIs. Now almost all the APIs return OpError as a common error type
except Lookup, Resolve and Parse APIs. The Lookup, Resolve and Parse
APIs return more specific errors such as DNSError, AddrError or
ParseError.

An OpError may contain nested error information. For example, Dial may
return an OpError containing a DNSError, AddrError, unexposed type/value
or other package's type/value like the following:
	OpError{/* dial info */, Err: &DNSError{}}
	OpError{/* dial info */, Err: &AddrError{}}
	OpError{/* dial info */, Err: <unexposed type or value>}
	OpError{/* dial info */, Err: <other package's type or value>}

and Read and Write may return an OpError containing other OpError when
an application uses io.Copy or similar:
	OpError{/* for io.Reader */, Err: &OpError{/* for io.Writer */}}

When an endpoint is created for connection-oriented byte-stream
protocols, Read may return an io.EOF when the connection is closed by
remote endpoint.

Fixes #4856.

A series of changes:
- net: fix inconsistent error values on Dial, Listen partially
  https://go.googlesource.com/go/+/89b7c66d0d14462fd7893be4290bdfe5f9063ae1
- net: fix inconsistent error values on Read
  https://go.googlesource.com/go/+/ec1144423f45e010c72363fe59291d43214b6e31
- net: fix inconsistent error values on Write
  https://go.googlesource.com/go/+/11b5f98bf0d5eb8854f735cc332c912725070214
- net: fix inconsistent error values on Close
  https://go.googlesource.com/go/+/310db63c5bc121e7bfccb494c01a6b91a257e7fc
- net: fix inconsistent error values on Accept
  https://go.googlesource.com/go/+/4540e162b1aefda8157372764ad3d290a414ef1d
- net: fix inconsistent error values on File
  https://go.googlesource.com/go/+/885111365ba0a74421059bfbd18f4c57c1e70332
- net: fix inconsistent error values on setters
  https://go.googlesource.com/go/+/2173a27903897c481b0a0daf3ca3e0a0685701db
- net: fix inconsistent error values on Interface
  https://go.googlesource.com/go/+/456cf0f22c93e1a6654980f4a48a564555f6c8a2
- net: fix inconsistent error values on Lookup
  https://go.googlesource.com/go/+/0fc582e87942b2e52bed751b6c56660ba99e9a7d
- net: add Source field to OpError
  https://go.googlesource.com/go/+/afd2d2b6df3ebfe99faf347030f15adfdf422fa0

Change-Id: Id678e369088dc9fbe9073cfe7ff8a8754a57d61f
Reviewed-on: https://go-review.googlesource.com/9236
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-05-05 09:40:07 +00:00
Alex A Skinner f390135733 net: make go DNS use localhost if resolv.conf is missing or empty
Per resolv.conf man page, "If this file does not exist, only the name
server on the local machine will be queried."

This behavior also occurs if file is present but unreadable,
or if no nameservers are listed.

Fixes #10566

Change-Id: Id5716da0eae534d5ebfafea111bbc657f302e307
Reviewed-on: https://go-review.googlesource.com/9380
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-04-30 18:19:00 +00:00
Mikio Hara afd2d2b6df net: add Source field to OpError
Not only by network, transport-layer intermediaries but by
virtualization stuff in a node, it is hard to identify the root cause of
weird faults without information of packet flows after disaster
happened.

This change adds Source field to OpError to be able to represent a
5-tuple of internet transport protocols for helping dealing with
complicated systems.

Also clarifies the usage of Source and Addr fields.

Updates #4856.

Change-Id: I96a523fe391ed14406bfb21604c461d4aac2fa19
Reviewed-on: https://go-review.googlesource.com/9231
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-29 22:37:30 +00:00
Mikio Hara 0fc582e879 net: fix inconsistent error values on Lookup
This change fixes inconsistent error values on
Lookup{Addr,CNAME,Host,IP.MX,NS,Port,SRV,TXT}.

Updates #4856.

Change-Id: I059bc8ffb96ee74dff8a8c4e8e6ae3e4a462a7ef
Reviewed-on: https://go-review.googlesource.com/9108
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-21 05:16:07 +00:00
Mikio Hara 2173a27903 net: fix inconsistent error values on setters
This change fixes inconsistent error values on
Set{Deadline,ReadDeadline,WriteDeadline,ReadBuffer,WriteBuffer} for
Conn, Listener and PacketConn, and
Set{KeepAlive,KeepAlivePeriod,Linger,NoDelay} for TCPConn.

Updates #4856.

Change-Id: I34ca5e98f6de72863f85b2527478b20d8d5394dd
Reviewed-on: https://go-review.googlesource.com/9109
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-21 04:05:59 +00:00
Mikio Hara 885111365b net: fix inconsistent error values on File
This change fixes inconsistent error values on
File{Conn,Listener,PacketConn} and File method of Conn, Listener.

Updates #4856.

Change-Id: I3197b9277bef0e034427e3a44fa77523acaa2520
Reviewed-on: https://go-review.googlesource.com/9101
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-21 03:37:41 +00:00
Mikio Hara 310db63c5b net: fix inconsistent error values on Close
This change fixes inconsistent error values on Close, CloseRead and
CloseWrite.

Updates #4856.

Change-Id: I3c4d46ccd7d6e1a2f52d8e75b512f62c533a368d
Reviewed-on: https://go-review.googlesource.com/8994
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-18 03:12:04 +00:00
Mikio Hara 11b5f98bf0 net: fix inconsistent error values on Write
This change fixes inconsistent error values on Write,
WriteTo{,UDP,IP,Unix} and WriteMsg{UDP,IP,Unix}.

Updates #4856.

Change-Id: I4208ab6a0650455ad7d70a80a2d6169351d6055f
Reviewed-on: https://go-review.googlesource.com/8993
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-18 02:44:08 +00:00
Mikio Hara ec1144423f net: fix inconsistent error values on Read
This change fixes inconsistent error values on Read,
ReadFrom{,UDP,IP,Unix} and ReadMsg{UDP,IP,Unix}.

Updates #4856.

Change-Id: I7de5663094e09be2d78cdb18ce6f1e7ec260888d
Reviewed-on: https://go-review.googlesource.com/8992
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-18 02:19:46 +00:00
Brad Fitzpatrick 47f095501e net: remove old comment
The memory model has been clarified since. This is legal and doesn't
need justification.

Change-Id: I60f9938503f86f52bb568ca1a99ac721ee72cee5
Reviewed-on: https://go-review.googlesource.com/8913
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
2015-04-14 04:38:20 +00:00
Mikio Hara 3a9024b498 net: move init function into net.go
It's a single, package-wide init function specified for the net package.

Change-Id: Id5894d65e1a92297cc16803cc5e4d4eef0b4b099
Reviewed-on: https://go-review.googlesource.com/8391
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-03 00:23:23 +00:00
Shenghou Ma 7e43aee301 net: document that user shouldn't modify returned Addr
Ideally, those methods should return a copy of the Addr, but
due to the Go 1 API guarantee, we cannot make that change now:
there might exist client code that uses the returned Addr as
map index and thus relies on the fact that different invocation
of the method returns the same pointer. Changing this behavior
will lead to hidden behaviour change in those programs.

Update #9654.

Change-Id: Iad4235f2ed7789b3a3c8e0993b9718cf0534ea2b
Reviewed-on: https://go-review.googlesource.com/3851
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-02-06 19:21:40 +00:00
Mikio Hara 5ab3823c6b net: update TDDO
The issue #8432 has been marked as an issue for golang.org/x/net.

Change-Id: Ia39abd99b685c820ea6169ee6505b16028e7e77f
Reviewed-on: https://go-review.googlesource.com/3836
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-02-04 04:57:32 +00:00
Brad Fitzpatrick dca460574f net: fix misleading package comment example
Fixes #8607

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/146470043
2014-09-29 12:24:06 -07:00