net: net: better IPv4 stack probe on Plan 9

LGTM=mischief, mikioh.mikioh
R=golang-codereviews, 0intro, mischief, mikioh.mikioh
CC=golang-codereviews
https://golang.org/cl/53960044

diff --git a/src/pkg/net/ipsock_plan9.go b/src/pkg/net/ipsock_plan9.go
index c2225002ee142bae31686e79d64cda2c26892fad..914ed50826f8c402ecb769460d16fe6996c1665a 100644 (file)
--- a/src/pkg/net/ipsock_plan9.go
+++ b/src/pkg/net/ipsock_plan9.go
@@ -12,7 +12,7 @@ import (
        "syscall"
 )
 
-func probe(filename, query string, bufSize int) bool {
+func probe(filename, query string) bool {
        var file *file
        var err error
        if file, err = open(filename); err != nil {
@@ -37,7 +37,7 @@ func probe(filename, query string, bufSize int) bool {
 }
 
 func probeIPv4Stack() bool {
-       return probe(netdir+"/ipselftab", "127.0.0.1", 128)
+       return probe(netdir+"/iproute", "4i")
 }
 
 // probeIPv6Stack returns two boolean values.  If the first boolean
@@ -45,10 +45,10 @@ func probeIPv4Stack() bool {
 // second boolean value is true, kernel supports IPv6 IPv4-mapping.
 func probeIPv6Stack() (supportsIPv6, supportsIPv4map bool) {
        // Plan 9 uses IPv6 natively, see ip(3).
-       r := probe(netdir+"/iproute", "6i", 128)
+       r := probe(netdir+"/iproute", "6i")
        v := false
        if r {
-               v = probe(netdir+"/iproute", "4b", 128)
+               v = probe(netdir+"/iproute", "4i")
        }
        return r, v
 }