104 lines
2.3 KiB
Go
104 lines
2.3 KiB
Go
package dsnet
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import (
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"fmt"
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"io/ioutil"
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"math/rand"
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"net"
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"net/http"
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"os"
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"strings"
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"time"
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)
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func Init() {
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_, err := os.Stat(CONFIG_FILE)
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if !os.IsNotExist(err) {
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ExitFail("Refusing to overwrite existing %s", CONFIG_FILE)
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}
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conf := DsnetConfig{
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PrivateKey: GenerateJSONPrivateKey(),
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ListenPort: DEFAULT_LISTEN_PORT,
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Network: getPrivateNet(),
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Network6: getULA(),
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Peers: []PeerConfig{},
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Domain: "dsnet",
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ReportFile: DEFAULT_REPORT_FILE,
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ExternalIP: getExternalIP(),
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InterfaceName: DEFAULT_INTERFACE_NAME,
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Networks: []JSONIPNet{},
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}
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IP := conf.MustAllocateIP()
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conf.IP = IP
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// DNS not set by default
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//conf.DNS = IP
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conf.MustSave()
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fmt.Printf("Config written to %s. Please check/edit.", CONFIG_FILE)
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}
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// get a random IPv4 /22 subnet on 10.0.0.0 (1023 hosts) (or /24?)
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func getPrivateNet() JSONIPNet {
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rbs := make([]byte, 2)
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rand.Seed(time.Now().UTC().UnixNano())
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rand.Read(rbs)
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return JSONIPNet{
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IPNet: net.IPNet{
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net.IP{10, rbs[0], rbs[1] << 2, 0},
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net.IPMask{255, 255, 252, 0},
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},
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}
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}
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func getULA() JSONIPNet {
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rbs := make([]byte, 5)
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rand.Seed(time.Now().UTC().UnixNano())
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rand.Read(rbs)
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// fc00 prefix with 40 bit global id and zero (16 bit) subnet ID
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return JSONIPNet{
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IPNet: net.IPNet{
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net.IP{0xfc, 0, rbs[0], rbs[1], rbs[2], rbs[3], rbs[4], 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
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net.IPMask{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0},
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},
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}
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}
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// TODO support IPv6
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func getExternalIP() net.IP {
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conn, err := net.Dial("udp", "8.8.8.8:80")
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check(err, "Could not detect internet connection")
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defer conn.Close()
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localAddr := conn.LocalAddr().String()
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IP := net.ParseIP(strings.Split(localAddr, ":")[0])
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IP = IP.To4()
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if !(IP[0] == 10 || (IP[0] == 172 && IP[1] >= 16 && IP[1] <= 31) || (IP[0] == 192 && IP[1] == 168)) {
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// not private, so public
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return IP
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}
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// detect private IP and use icanhazip.com instead
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client := http.Client{
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Timeout: 5 * time.Second,
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}
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resp, err := client.Get("https://ipv4.icanhazip.com/")
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check(err)
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defer resp.Body.Close()
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if resp.StatusCode == http.StatusOK {
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body, err := ioutil.ReadAll(resp.Body)
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check(err)
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IP = net.ParseIP(strings.TrimSpace(string(body)))
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return IP.To4()
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}
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return net.IP{}
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}
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