udp timeout on MacOS X
Miek Gieben
For the Go DNS [*] package I create some example programs one
of which is called 'q' [**]. This acts the same of the dns
query tool 'dig' which you may have heard of.
'q' basically opens an udp port, sends a query and waits for
the reply. This all works correct on Ubuntu with the lastest
weekly. On mac OS X I keep getting reports about i/o timeouts.
For tcp connection both Ubuntu and mac OS X work fine.
I don't own a machine with mac OS X, could someone with such
software double check? 'q @open.nlnetlabs.nl MX miek.nl' should
give such a timeout.
[*]
https://github.com/miekg/godns
[**]
http://www.miek.nl/blog/archives/2012/01/23/super-short_guide_to_getting_q/index.html
grtz,
--
Miek
Dave Cheney
odessa(~/devel/godns/examples/q) % ./q @open.nlnetlabs.nl MX miek.nl
read udp 192.168.1.129:62764: i/o timeout
Miek Gieben
> darwin/amd64 lion 10.7.2
>
> odessa(~/devel/godns/examples/q) % ./q @open.nlnetlabs.nl MX miek.nl
> read udp 192.168.1.129:62764: i/o timeout
Thanks for the quick test :-)
Ok, now what? It works on Ubuntu, and I do believe I'm using the
new SetDeadline stuff OK.
I will try to skim through the net's dns*.go files to see what happens
there.
grtz Miek
Yves Junqueira
Sorry if i cant't be more precise right now, but there were changes to socket default settings in various platforms - this may be affecting you. Look for recent changes to the net package by Mikio Hara (IIRC), that might give you some light.
(phone)
Mikio Hara
On Tue, Jan 24, 2012 at 7:22 PM, Yves Junqueira
<yves.ju...@gmail.com> wrote:
> Sorry if i cant't be more precise right now, but there were changes to
> socket default settings in various platforms - this may be affecting you.
> Look for recent changes to the net package by Mikio Hara (IIRC), that might
> give you some light.
Looks like all BSD variants have same problem.
I just tried mx: "dtruss ./mx golang.org" on both darwin and freebsd,
got same error EISCONN, strange.
socket(0x2, 0x2, 0x0) = 7 0
fcntl(0x7, 0x2, 0x1) = 0 0
setsockopt(0x7, 0xFFFF, 0x20) = 0 0 // set socket to SO_BROADCAST
fcntl(0x7, 0x3, 0x0) = 2 0
fcntl(0x7, 0x4, 0x6) = 0 0
connect(0x7, 0xF8400026A8, 0x10) = 0 0
getsockname(0x7, 0xF840000C40, 0xF840011150) = 0 0
getpeername(0x7, 0xF840000BD0, 0xF840011158) = 0 0
gettimeofday(0x22BFAC8, 0x0, 0x22BFD38) = 1327408294 0
gettimeofday(0x22BFAC8, 0x0, 0x2) = 1327408294 0
sendto(0x7, 0xF84001DFC0, 0x1C) = -1 Err#56
shutdown(0x7, 0x2, 0x0) = 0 0
fcntl(0x7, 0x3, 0x0) = 6 0
fcntl(0x7, 0x4, 0x2) = 0 0
close(0x7) = 0 0
write(0x1, "write udp 192.168.12.1:53: socket is already
connected\n\0", 0x37) = 55 0
Miek Gieben
> Yikes!
>
> Looks like all BSD variants have same problem.
> I just tried mx: "dtruss ./mx golang.org" on both darwin and freebsd,
> got same error EISCONN, strange.
>
<SNIP>
> fcntl(0x7, 0x4, 0x2) = 0 0
> close(0x7) = 0 0
> write(0x1, "write udp 192.168.12.1:53: socket is already connected\n\0", 0x37) = 55 0
But is this my fault (as in: my Go code is wrong)? Or is this something deep in
Go?
grtz,
--
Miek
Mikio Hara
> But is this my fault (as in: my Go code is wrong)? Or is this something deep in
> Go?
Ah, hard to say.
Here is a result of toy experiment on socket stuff
with attached source code.
Darwin:
2012/01/24 23:46:05 WriteTo with CO socket: darwin write udp
8.8.8.8:53: socket is already connected
2012/01/24 23:46:05 Write with CL socket: darwin write udp:
destination address required
FreeBSD:
2012/01/24 23:46:51 WriteTo with CO socket: freebsd write udp
8.8.8.8:53: socket is already connected
2012/01/24 23:46:51 Write with CL socket: freebsd write udp:
destination address required
Linux:
2012/01/24 23:46:11 Write with CL socket: linux write udp: destination
address required
--
package main
import (
"log"
"net"
"runtime"
)
func main() {
la := &net.UDPAddr{} // wildcard
ra, err := net.ResolveUDPAddr("udp", "8.8.8.8:53")
if err != nil {
log.Fatal(err)
}
c, err := net.DialUDP("udp", nil, ra)
if err != nil {
log.Fatal(err)
}
_, err = c.WriteTo([]byte("ABCD"), ra)
if err != nil {
log.Println("WriteTo with CO socket:", runtime.GOOS, err)
}
_, err = c.Write([]byte("ABCD"))
if err != nil {
log.Println("Write with CO socket:", runtime.GOOS, err)
}
l, err := net.ListenUDP("udp", la)
if err != nil {
log.Fatal(err)
}
_, err = l.WriteTo([]byte("ABCD"), ra)
if err != nil {
log.Println("WriteTo with CL socket:", runtime.GOOS, err)
}
_, err = l.Write([]byte("ABCD"))
if err != nil {
log.Println("Write with CL socket:", runtime.GOOS, err)
}
}
Brad Fitzpatrick
Mikio Hara
> Please file a bug if you haven't already.
Some supplementary:
Seems like sendto with connection-oriented mode socket
on Linux can ignore or override pre-specified address.
That's the reason why godns apps work on Linux.
Returning error on write with connection-less mode socket
seems correct behavior.
Mikio Hara
On Tue, Jan 24, 2012 at 10:19 PM, Miek Gieben <mi...@miek.nl> wrote:
> But is this my fault (as in: my Go code is wrong)? Or is this something deep in
> Go?
Filed issue 2773.