github.com/johnathanhowell/sia@v0.5.1-beta.0.20160524050156-83dcc3d37c94/modules/host/upnp.go (about)

     1  package host
     2  
     3  import (
     4  	"io"
     5  	"net"
     6  	"net/http"
     7  	"strconv"
     8  	"time"
     9  
    10  	"github.com/NebulousLabs/go-upnp"
    11  
    12  	"github.com/NebulousLabs/Sia/build"
    13  	"github.com/NebulousLabs/Sia/modules"
    14  )
    15  
    16  // myExternalIP discovers the host's external IP by querying a centralized
    17  // service, http://myexternalip.com.
    18  func myExternalIP() (string, error) {
    19  	// timeout after 10 seconds
    20  	client := http.Client{Timeout: time.Duration(10 * time.Second)}
    21  	resp, err := client.Get("http://myexternalip.com/raw")
    22  	if err != nil {
    23  		return "", err
    24  	}
    25  	defer resp.Body.Close()
    26  	buf := make([]byte, 64)
    27  	n, err := resp.Body.Read(buf)
    28  	if err != nil && err != io.EOF {
    29  		return "", err
    30  	}
    31  	// trim newline
    32  	return string(buf[:n-1]), nil
    33  }
    34  
    35  // managedLearnHostname discovers the external IP of the Host. If the host's
    36  // net address is blank and the host's auto address appears to have changed,
    37  // the host will make an announcement on the blockchain.
    38  func (h *Host) managedLearnHostname() {
    39  	if build.Release == "testing" {
    40  		return
    41  	}
    42  	h.mu.RLock()
    43  	netAddr := h.settings.NetAddress
    44  	h.mu.RUnlock()
    45  	// If the settings indicate that an address has been manually set, there is
    46  	// no reason to learn the hostname.
    47  	if netAddr != "" {
    48  		return
    49  	}
    50  
    51  	// try UPnP first, then fallback to myexternalip.com
    52  	var hostname string
    53  	d, err := upnp.Discover()
    54  	if err == nil {
    55  		hostname, err = d.ExternalIP()
    56  	}
    57  	if err != nil {
    58  		hostname, err = myExternalIP()
    59  	}
    60  	if err != nil {
    61  		h.log.Println("WARN: failed to discover external IP")
    62  		return
    63  	}
    64  
    65  	h.mu.Lock()
    66  	defer h.mu.Unlock()
    67  	autoAddress := modules.NetAddress(net.JoinHostPort(hostname, h.port))
    68  	if err := autoAddress.IsValid(); err != nil {
    69  		h.log.Printf("WARN: discovered hostname %q is invalid: %v", autoAddress, err)
    70  		return
    71  	}
    72  	if autoAddress == h.autoAddress && h.announced {
    73  		// Nothing to do - the auto address has not changed and the previous
    74  		// annoucement was successful.
    75  		return
    76  	}
    77  	err = h.announce(autoAddress)
    78  	if err != nil {
    79  		// Set h.announced to false, as the address has changed yet the
    80  		// renewed annoucement has failed.
    81  		h.announced = false
    82  		h.log.Debugln(err)
    83  	}
    84  	h.autoAddress = autoAddress
    85  	err = h.save()
    86  	if err != nil {
    87  		h.log.Println(err)
    88  	}
    89  }
    90  
    91  // managedForwardPort adds a port mapping to the router.
    92  func (h *Host) managedForwardPort() error {
    93  	// If the port is invalid, there is no need to perform any of the other
    94  	// tasks.
    95  	h.mu.RLock()
    96  	port := h.port
    97  	h.mu.RUnlock()
    98  	portInt, err := strconv.Atoi(port)
    99  	if err != nil {
   100  		return err
   101  	}
   102  	if build.Release == "testing" {
   103  		return nil
   104  	}
   105  
   106  	d, err := upnp.Discover()
   107  	if err != nil {
   108  		return err
   109  	}
   110  	err = d.Forward(uint16(portInt), "Sia Host")
   111  	if err != nil {
   112  		return err
   113  	}
   114  
   115  	h.log.Println("INFO: successfully forwarded port", port)
   116  	return nil
   117  }
   118  
   119  // managedClearPort removes a port mapping from the router.
   120  func (h *Host) managedClearPort() error {
   121  	// If the port is invalid, there is no need to perform any of the other
   122  	// tasks.
   123  	h.mu.RLock()
   124  	port := h.port
   125  	h.mu.RUnlock()
   126  	portInt, err := strconv.Atoi(port)
   127  	if err != nil {
   128  		return err
   129  	}
   130  	if build.Release == "testing" {
   131  		return nil
   132  	}
   133  
   134  	d, err := upnp.Discover()
   135  	if err != nil {
   136  		return err
   137  	}
   138  	err = d.Clear(uint16(portInt))
   139  	if err != nil {
   140  		return err
   141  	}
   142  
   143  	h.log.Println("INFO: successfully unforwarded port", port)
   144  	return nil
   145  }