mirror of https://github.com/perkeep/perkeep.git
124 lines
3.2 KiB
Go
124 lines
3.2 KiB
Go
/*
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Copyright 2014 The Camlistore Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package netutil
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import (
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"errors"
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"fmt"
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"net"
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"net/url"
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"strings"
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"time"
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)
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// AwaitReachable tries to make a TCP connection to addr regularly.
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// It returns an error if it's unable to make a connection before maxWait.
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func AwaitReachable(addr string, maxWait time.Duration) error {
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done := time.Now().Add(maxWait)
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for time.Now().Before(done) {
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c, err := net.Dial("tcp", addr)
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if err == nil {
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c.Close()
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return nil
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}
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time.Sleep(100 * time.Millisecond)
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}
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return fmt.Errorf("%v unreachable for %v", addr, maxWait)
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}
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// HostPort takes a urlStr string URL, and returns a host:port string suitable
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// to passing to net.Dial, with the port set as the scheme's default port if
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// absent.
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func HostPort(urlStr string) (string, error) {
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u, err := url.Parse(urlStr)
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if err != nil {
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return "", fmt.Errorf("could not parse %q as a url: %v", urlStr, err)
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}
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if u.Scheme == "" {
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return "", fmt.Errorf("url %q has no scheme", urlStr)
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}
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hostPort := u.Host
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if hostPort == "" || strings.HasPrefix(hostPort, ":") {
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return "", fmt.Errorf("url %q has no host", urlStr)
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}
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idx := strings.Index(hostPort, "]")
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if idx == -1 {
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idx = 0
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}
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if !strings.Contains(hostPort[idx:], ":") {
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if u.Scheme == "https" {
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hostPort += ":443"
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} else {
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hostPort += ":80"
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}
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}
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return hostPort, nil
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}
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// ListenOnLocalRandomPort returns a TCP listener on a random
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// localhost port.
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func ListenOnLocalRandomPort() (net.Listener, error) {
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ip, err := Localhost()
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if err != nil {
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return nil, err
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}
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return net.ListenTCP("tcp", &net.TCPAddr{IP: ip, Port: 0})
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}
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// Localhost returns the first address found when
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// doing a lookup of "localhost". If not successful,
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// it looks for an ip on the loopback interfaces.
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func Localhost() (net.IP, error) {
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if ip := localhostLookup(); ip != nil {
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return ip, nil
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}
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if ip := loopbackIP(); ip != nil {
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return ip, nil
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}
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return nil, errors.New("No loopback ip found.")
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}
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// localhostLookup looks for a loopback IP by resolving localhost.
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func localhostLookup() net.IP {
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if ips, err := net.LookupIP("localhost"); err == nil && len(ips) > 0 {
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return ips[0]
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}
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return nil
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}
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// loopbackIP returns the first loopback IP address sniffing network
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// interfaces or nil if none is found.
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func loopbackIP() net.IP {
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interfaces, err := net.Interfaces()
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if err != nil {
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return nil
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}
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for _, inf := range interfaces {
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const flagUpLoopback = net.FlagUp | net.FlagLoopback
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if inf.Flags&flagUpLoopback == flagUpLoopback {
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addrs, _ := inf.Addrs()
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for _, addr := range addrs {
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ip, _, err := net.ParseCIDR(addr.String())
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if err == nil && ip.IsLoopback() {
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return ip
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}
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}
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}
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}
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return nil
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}
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