Gecko [ 167.86.127.34 ]

Name	Size	Permission
http	[ DIR ]	drwxr-xr-x
internal	[ DIR ]	drwxr-xr-x
mail	[ DIR ]	drwxr-xr-x
rpc	[ DIR ]	drwxr-xr-x
smtp	[ DIR ]	drwxr-xr-x
testdata	[ DIR ]	drwxr-xr-x
textproto	[ DIR ]	drwxr-xr-x
url	[ DIR ]	drwxr-xr-x
addrselect.go	9.51 KB	-rw-r--r--
addrselect_test.go	6.2 KB	-rw-r--r--
cgo_aix.go	578 B	-rw-r--r--
cgo_android.go	268 B	-rw-r--r--
cgo_bsd.go	348 B	-rw-r--r--
cgo_linux.go	635 B	-rw-r--r--
cgo_netbsd.go	272 B	-rw-r--r--
cgo_openbsd.go	272 B	-rw-r--r--
cgo_resnew.go	577 B	-rw-r--r--
cgo_resold.go	571 B	-rw-r--r--
cgo_socknew.go	748 B	-rw-r--r--
cgo_sockold.go	838 B	-rw-r--r--
cgo_solaris.go	339 B	-rw-r--r--
cgo_stub.go	1.06 KB	-rw-r--r--
cgo_unix.go	9.53 KB	-rw-r--r--
cgo_unix_test.go	1.89 KB	-rw-r--r--
cgo_windows.go	398 B	-rw-r--r--
conf.go	8.88 KB	-rw-r--r--
conf_netcgo.go	369 B	-rw-r--r--
conf_test.go	9.59 KB	-rw-r--r--
conn_test.go	1.77 KB	-rw-r--r--
dial.go	22.44 KB	-rw-r--r--
dial_test.go	27 KB	-rw-r--r--
dial_unix_test.go	2.74 KB	-rw-r--r--
dnsclient.go	5.34 KB	-rw-r--r--
dnsclient_test.go	1.54 KB	-rw-r--r--
dnsclient_unix.go	21.86 KB	-rw-r--r--
dnsclient_unix_test.go	45.17 KB	-rw-r--r--
dnsconfig_unix.go	5.47 KB	-rw-r--r--
dnsconfig_unix_test.go	6.73 KB	-rw-r--r--
dnsname_test.go	1.98 KB	-rw-r--r--
error_plan9.go	224 B	-rw-r--r--
error_plan9_test.go	398 B	-rw-r--r--
error_posix.go	583 B	-rw-r--r--
error_posix_test.go	980 B	-rw-r--r--
error_test.go	19.39 KB	-rw-r--r--
error_unix.go	421 B	-rw-r--r--
error_unix_test.go	672 B	-rw-r--r--
error_windows.go	355 B	-rw-r--r--
error_windows_test.go	483 B	-rw-r--r--
example_test.go	3.16 KB	-rw-r--r--
external_test.go	4.07 KB	-rw-r--r--
fd_plan9.go	3.56 KB	-rw-r--r--
fd_unix.go	7.36 KB	-rw-r--r--
fd_windows.go	6.49 KB	-rw-r--r--
file.go	1.69 KB	-rw-r--r--
file_plan9.go	2.68 KB	-rw-r--r--
file_stub.go	485 B	-rw-r--r--
file_test.go	6.53 KB	-rw-r--r--
file_unix.go	2.51 KB	-rw-r--r--
file_windows.go	521 B	-rw-r--r--
hook.go	628 B	-rw-r--r--
hook_plan9.go	283 B	-rw-r--r--
hook_unix.go	734 B	-rw-r--r--
hook_windows.go	875 B	-rw-r--r--
hosts.go	3.1 KB	-rw-r--r--
hosts_test.go	4.65 KB	-rw-r--r--
interface.go	7.14 KB	-rw-r--r--
interface_aix.go	4.41 KB	-rw-r--r--
interface_bsd.go	2.74 KB	-rw-r--r--
interface_bsd_test.go	1.42 KB	-rw-r--r--
interface_bsdvar.go	711 B	-rw-r--r--
interface_darwin.go	1.29 KB	-rw-r--r--
interface_freebsd.go	1.42 KB	-rw-r--r--
interface_linux.go	6.9 KB	-rw-r--r--
interface_linux_test.go	3.65 KB	-rw-r--r--
interface_plan9.go	4.59 KB	-rw-r--r--
interface_solaris.go	2.46 KB	-rw-r--r--
interface_stub.go	808 B	-rw-r--r--
interface_test.go	9.67 KB	-rw-r--r--
interface_unix_test.go	4.69 KB	-rw-r--r--
interface_windows.go	5.41 KB	-rw-r--r--
ip.go	16.61 KB	-rw-r--r--
ip_test.go	23.96 KB	-rw-r--r--
iprawsock.go	7.08 KB	-rw-r--r--
iprawsock_plan9.go	874 B	-rw-r--r--
iprawsock_posix.go	3.45 KB	-rw-r--r--
iprawsock_test.go	5.62 KB	-rw-r--r--
ipsock.go	8.77 KB	-rw-r--r--
ipsock_plan9.go	6.25 KB	-rw-r--r--
ipsock_posix.go	6.16 KB	-rw-r--r--
ipsock_test.go	6.81 KB	-rw-r--r--
listen_test.go	21.32 KB	-rw-r--r--
lookup.go	15.45 KB	-rw-r--r--
lookup_fake.go	1.64 KB	-rw-r--r--
lookup_plan9.go	7.68 KB	-rw-r--r--
lookup_test.go	29.14 KB	-rw-r--r--
lookup_unix.go	8.78 KB	-rw-r--r--
lookup_windows.go	11.74 KB	-rw-r--r--
lookup_windows_test.go	8 KB	-rw-r--r--
mac.go	1.88 KB	-rw-r--r--
mac_test.go	3.26 KB	-rw-r--r--
main_cloexec_test.go	669 B	-rw-r--r--
main_conf_test.go	915 B	-rw-r--r--
main_noconf_test.go	493 B	-rw-r--r--
main_plan9_test.go	392 B	-rw-r--r--
main_posix_test.go	1.37 KB	-rw-r--r--
main_test.go	7.11 KB	-rw-r--r--
main_unix_test.go	1.24 KB	-rw-r--r--
main_windows_test.go	1.08 KB	-rw-r--r--
mockserver_test.go	11.23 KB	-rw-r--r--
net.go	20.9 KB	-rw-r--r--
net_fake.go	5.34 KB	-rw-r--r--
net_test.go	12.1 KB	-rw-r--r--
net_windows_test.go	15.94 KB	-rw-r--r--
netgo_unix_test.go	631 B	-rw-r--r--
nss.go	3.71 KB	-rw-r--r--
nss_test.go	3.33 KB	-rw-r--r--
packetconn_test.go	3.56 KB	-rw-r--r--
parse.go	7.82 KB	-rw-r--r--
parse_test.go	2.14 KB	-rw-r--r--
pipe.go	5.59 KB	-rw-r--r--
pipe_test.go	1.2 KB	-rw-r--r--
platform_test.go	4.59 KB	-rw-r--r--
port.go	1.46 KB	-rw-r--r--
port_test.go	1.34 KB	-rw-r--r--
port_unix.go	1.28 KB	-rw-r--r--
protoconn_test.go	7.22 KB	-rw-r--r--
rawconn.go	1.89 KB	-rw-r--r--
rawconn_stub_test.go	622 B	-rw-r--r--
rawconn_test.go	4.52 KB	-rw-r--r--
rawconn_unix_test.go	3.15 KB	-rw-r--r--
rawconn_windows_test.go	3.26 KB	-rw-r--r--
sendfile_linux.go	1.1 KB	-rw-r--r--
sendfile_stub.go	329 B	-rw-r--r--
sendfile_test.go	5.69 KB	-rw-r--r--
sendfile_unix_alt.go	1.98 KB	-rw-r--r--
sendfile_windows.go	1.02 KB	-rw-r--r--
server_test.go	11.55 KB	-rw-r--r--
sock_bsd.go	898 B	-rw-r--r--
sock_cloexec.go	1.46 KB	-rw-r--r--
sock_linux.go	644 B	-rw-r--r--
sock_plan9.go	262 B	-rw-r--r--
sock_posix.go	6.83 KB	-rw-r--r--
sock_stub.go	378 B	-rw-r--r--
sock_windows.go	1.16 KB	-rw-r--r--
sockaddr_posix.go	955 B	-rw-r--r--
sockopt_aix.go	1.32 KB	-rw-r--r--
sockopt_bsd.go	2.09 KB	-rw-r--r--
sockopt_linux.go	1.14 KB	-rw-r--r--
sockopt_plan9.go	406 B	-rw-r--r--
sockopt_posix.go	2.67 KB	-rw-r--r--
sockopt_solaris.go	1.14 KB	-rw-r--r--
sockopt_stub.go	738 B	-rw-r--r--
sockopt_windows.go	1.34 KB	-rw-r--r--
sockoptip_bsdvar.go	848 B	-rw-r--r--
sockoptip_linux.go	735 B	-rw-r--r--
sockoptip_posix.go	1.43 KB	-rw-r--r--
sockoptip_stub.go	949 B	-rw-r--r--
sockoptip_windows.go	819 B	-rw-r--r--
splice_linux.go	1.09 KB	-rw-r--r--
splice_stub.go	286 B	-rw-r--r--
splice_test.go	10.51 KB	-rw-r--r--
sys_cloexec.go	977 B	-rw-r--r--
tcpsock.go	9.85 KB	-rw-r--r--
tcpsock_plan9.go	2.13 KB	-rw-r--r--
tcpsock_posix.go	5.27 KB	-rw-r--r--
tcpsock_test.go	17.51 KB	-rw-r--r--
tcpsock_unix_test.go	2.38 KB	-rw-r--r--
tcpsockopt_darwin.go	770 B	-rw-r--r--
tcpsockopt_dragonfly.go	698 B	-rw-r--r--
tcpsockopt_openbsd.go	365 B	-rw-r--r--
tcpsockopt_plan9.go	503 B	-rw-r--r--
tcpsockopt_posix.go	491 B	-rw-r--r--
tcpsockopt_solaris.go	1.15 KB	-rw-r--r--
tcpsockopt_stub.go	393 B	-rw-r--r--
tcpsockopt_unix.go	712 B	-rw-r--r--
tcpsockopt_windows.go	741 B	-rw-r--r--
timeout_test.go	23.18 KB	-rw-r--r--
udpsock.go	8.7 KB	-rw-r--r--
udpsock_plan9.go	3.77 KB	-rw-r--r--
udpsock_plan9_test.go	1.31 KB	-rw-r--r--
udpsock_posix.go	4.09 KB	-rw-r--r--
udpsock_test.go	11.18 KB	-rw-r--r--
unixsock.go	10.17 KB	-rw-r--r--
unixsock_linux_test.go	2.29 KB	-rw-r--r--
unixsock_plan9.go	1.24 KB	-rw-r--r--
unixsock_posix.go	5.81 KB	-rw-r--r--
unixsock_test.go	10.58 KB	-rw-r--r--
unixsock_windows_test.go	2.07 KB	-rw-r--r--
write_unix_test.go	1.59 KB	-rw-r--r--
writev_test.go	5.01 KB	-rw-r--r--
writev_unix.go	706 B	-rw-r--r--

Code Editor : conf.go

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris

package net

import (
	"internal/bytealg"
	"os"
	"runtime"
	"sync"
	"syscall"
)

// conf represents a system's network configuration.
type conf struct {
	// forceCgoLookupHost forces CGO to always be used, if available.
	forceCgoLookupHost bool

netGo  bool // go DNS resolution forced
	netCgo bool // cgo DNS resolution forced

// machine has an /etc/mdns.allow file
	hasMDNSAllow bool

goos          string // the runtime.GOOS, to ease testing
	dnsDebugLevel int

nss    *nssConf
	resolv *dnsConfig
}

var (
	confOnce sync.Once // guards init of confVal via initConfVal
	confVal  = &conf{goos: runtime.GOOS}
)

// systemConf returns the machine's network configuration.
func systemConf() *conf {
	confOnce.Do(initConfVal)
	return confVal
}

func initConfVal() {
	dnsMode, debugLevel := goDebugNetDNS()
	confVal.dnsDebugLevel = debugLevel
	confVal.netGo = netGo || dnsMode == "go"
	confVal.netCgo = netCgo || dnsMode == "cgo"

if confVal.dnsDebugLevel > 0 {
		defer func() {
			switch {
			case confVal.netGo:
				if netGo {
					println("go package net: built with netgo build tag; using Go's DNS resolver")
				} else {
					println("go package net: GODEBUG setting forcing use of Go's resolver")
				}
			case confVal.forceCgoLookupHost:
				println("go package net: using cgo DNS resolver")
			default:
				println("go package net: dynamic selection of DNS resolver")
			}
		}()
	}

// Darwin pops up annoying dialog boxes if programs try to do
	// their own DNS requests. So always use cgo instead, which
	// avoids that.
	if runtime.GOOS == "darwin" {
		confVal.forceCgoLookupHost = true
		return
	}

// If any environment-specified resolver options are specified,
	// force cgo. Note that LOCALDOMAIN can change behavior merely
	// by being specified with the empty string.
	_, localDomainDefined := syscall.Getenv("LOCALDOMAIN")
	if os.Getenv("RES_OPTIONS") != "" ||
		os.Getenv("HOSTALIASES") != "" ||
		confVal.netCgo ||
		localDomainDefined {
		confVal.forceCgoLookupHost = true
		return
	}

// OpenBSD apparently lets you override the location of resolv.conf
	// with ASR_CONFIG. If we notice that, defer to libc.
	if runtime.GOOS == "openbsd" && os.Getenv("ASR_CONFIG") != "" {
		confVal.forceCgoLookupHost = true
		return
	}

if runtime.GOOS != "openbsd" {
		confVal.nss = parseNSSConfFile("/etc/nsswitch.conf")
	}

confVal.resolv = dnsReadConfig("/etc/resolv.conf")
	if confVal.resolv.err != nil && !os.IsNotExist(confVal.resolv.err) &&
		!os.IsPermission(confVal.resolv.err) {
		// If we can't read the resolv.conf file, assume it
		// had something important in it and defer to cgo.
		// libc's resolver might then fail too, but at least
		// it wasn't our fault.
		confVal.forceCgoLookupHost = true
	}

if _, err := os.Stat("/etc/mdns.allow"); err == nil {
		confVal.hasMDNSAllow = true
	}
}

// canUseCgo reports whether calling cgo functions is allowed
// for non-hostname lookups.
func (c *conf) canUseCgo() bool {
	return c.hostLookupOrder(nil, "") == hostLookupCgo
}

// hostLookupOrder determines which strategy to use to resolve hostname.
// The provided Resolver is optional. nil means to not consider its options.
func (c *conf) hostLookupOrder(r *Resolver, hostname string) (ret hostLookupOrder) {
	if c.dnsDebugLevel > 1 {
		defer func() {
			print("go package net: hostLookupOrder(", hostname, ") = ", ret.String(), "\n")
		}()
	}
	fallbackOrder := hostLookupCgo
	if c.netGo || r.preferGo() {
		fallbackOrder = hostLookupFilesDNS
	}
	if c.forceCgoLookupHost || c.resolv.unknownOpt || c.goos == "android" {
		return fallbackOrder
	}
	if bytealg.IndexByteString(hostname, '\\') != -1 || bytealg.IndexByteString(hostname, '%') != -1 {
		// Don't deal with special form hostnames with backslashes
		// or '%'.
		return fallbackOrder
	}

// OpenBSD is unique and doesn't use nsswitch.conf.
	// It also doesn't support mDNS.
	if c.goos == "openbsd" {
		// OpenBSD's resolv.conf manpage says that a non-existent
		// resolv.conf means "lookup" defaults to only "files",
		// without DNS lookups.
		if os.IsNotExist(c.resolv.err) {
			return hostLookupFiles
		}
		lookup := c.resolv.lookup
		if len(lookup) == 0 {
			// https://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man5/resolv.conf.5
			// "If the lookup keyword is not used in the
			// system's resolv.conf file then the assumed
			// order is 'bind file'"
			return hostLookupDNSFiles
		}
		if len(lookup) < 1 || len(lookup) > 2 {
			return fallbackOrder
		}
		switch lookup[0] {
		case "bind":
			if len(lookup) == 2 {
				if lookup[1] == "file" {
					return hostLookupDNSFiles
				}
				return fallbackOrder
			}
			return hostLookupDNS
		case "file":
			if len(lookup) == 2 {
				if lookup[1] == "bind" {
					return hostLookupFilesDNS
				}
				return fallbackOrder
			}
			return hostLookupFiles
		default:
			return fallbackOrder
		}
	}

// Canonicalize the hostname by removing any trailing dot.
	if stringsHasSuffix(hostname, ".") {
		hostname = hostname[:len(hostname)-1]
	}
	if stringsHasSuffixFold(hostname, ".local") {
		// Per RFC 6762, the ".local" TLD is special. And
		// because Go's native resolver doesn't do mDNS or
		// similar local resolution mechanisms, assume that
		// libc might (via Avahi, etc) and use cgo.
		return fallbackOrder
	}

nss := c.nss
	srcs := nss.sources["hosts"]
	// If /etc/nsswitch.conf doesn't exist or doesn't specify any
	// sources for "hosts", assume Go's DNS will work fine.
	if os.IsNotExist(nss.err) || (nss.err == nil && len(srcs) == 0) {
		if c.goos == "solaris" {
			// illumos defaults to "nis [NOTFOUND=return] files"
			return fallbackOrder
		}
		if c.goos == "linux" {
			// glibc says the default is "dns [!UNAVAIL=return] files"
			// https://www.gnu.org/software/libc/manual/html_node/Notes-on-NSS-Configuration-File.html.
			return hostLookupDNSFiles
		}
		return hostLookupFilesDNS
	}
	if nss.err != nil {
		// We failed to parse or open nsswitch.conf, so
		// conservatively assume we should use cgo if it's
		// available.
		return fallbackOrder
	}

var mdnsSource, filesSource, dnsSource bool
	var first string
	for _, src := range srcs {
		if src.source == "myhostname" {
			if isLocalhost(hostname) || isGateway(hostname) {
				return fallbackOrder
			}
			hn, err := getHostname()
			if err != nil || stringsEqualFold(hostname, hn) {
				return fallbackOrder
			}
			continue
		}
		if src.source == "files" || src.source == "dns" {
			if !src.standardCriteria() {
				return fallbackOrder // non-standard; let libc deal with it.
			}
			if src.source == "files" {
				filesSource = true
			} else if src.source == "dns" {
				dnsSource = true
			}
			if first == "" {
				first = src.source
			}
			continue
		}
		if stringsHasPrefix(src.source, "mdns") {
			// e.g. "mdns4", "mdns4_minimal"
			// We already returned true before if it was *.local.
			// libc wouldn't have found a hit on this anyway.
			mdnsSource = true
			continue
		}
		// Some source we don't know how to deal with.
		return fallbackOrder
	}

// We don't parse mdns.allow files. They're rare. If one
	// exists, it might list other TLDs (besides .local) or even
	// '*', so just let libc deal with it.
	if mdnsSource && c.hasMDNSAllow {
		return fallbackOrder
	}

// Cases where Go can handle it without cgo and C thread
	// overhead.
	switch {
	case filesSource && dnsSource:
		if first == "files" {
			return hostLookupFilesDNS
		} else {
			return hostLookupDNSFiles
		}
	case filesSource:
		return hostLookupFiles
	case dnsSource:
		return hostLookupDNS
	}

// Something weird. Let libc deal with it.
	return fallbackOrder
}

// goDebugNetDNS parses the value of the GODEBUG "netdns" value.
// The netdns value can be of the form:
//    1       // debug level 1
//    2       // debug level 2
//    cgo     // use cgo for DNS lookups
//    go      // use go for DNS lookups
//    cgo+1   // use cgo for DNS lookups + debug level 1
//    1+cgo   // same
//    cgo+2   // same, but debug level 2
// etc.
func goDebugNetDNS() (dnsMode string, debugLevel int) {
	goDebug := goDebugString("netdns")
	parsePart := func(s string) {
		if s == "" {
			return
		}
		if '0' <= s[0] && s[0] <= '9' {
			debugLevel, _, _ = dtoi(s)
		} else {
			dnsMode = s
		}
	}
	if i := bytealg.IndexByteString(goDebug, '+'); i != -1 {
		parsePart(goDebug[:i])
		parsePart(goDebug[i+1:])
		return
	}
	parsePart(goDebug)
	return
}

// isLocalhost reports whether h should be considered a "localhost"
// name for the myhostname NSS module.
func isLocalhost(h string) bool {
	return stringsEqualFold(h, "localhost") || stringsEqualFold(h, "localhost.localdomain") || stringsHasSuffixFold(h, ".localhost") || stringsHasSuffixFold(h, ".localhost.localdomain")
}

// isGateway reports whether h should be considered a "gateway"
// name for the myhostname NSS module.
func isGateway(h string) bool {
	return stringsEqualFold(h, "gateway")
}

${this.title}

Code Editor : conf.go