dht: Move security functions into new file

diff --git a/dht/dht.go b/dht/dht.go
index 4fef734ddd7882056c1757de9812fc58475bd459..6df2c225dc1d0aa2e81fbdd553d4fb43236727d6 100644 (file)
--- a/dht/dht.go
+++ b/dht/dht.go
@@ -3,8 +3,6 @@ package dht
 import (
        _ "crypto/sha1"
        "errors"
-       "fmt"
-       "hash/crc32"
        "math/big"
        "math/rand"
        "net"
@@ -193,62 +191,6 @@ func jitterDuration(average time.Duration, plusMinus time.Duration) time.Duratio
        return average - plusMinus/2 + time.Duration(rand.Int63n(int64(plusMinus)))
 }
 
-func maskForIP(ip net.IP) []byte {
-       switch {
-       case ip.To4() != nil:
-               return []byte{0x03, 0x0f, 0x3f, 0xff}
-       default:
-               return []byte{0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff}
-       }
-}
-
-// Generate the CRC used to make or validate secure node ID.
-func crcIP(ip net.IP, rand uint8) uint32 {
-       if ip4 := ip.To4(); ip4 != nil {
-               ip = ip4
-       }
-       // Copy IP so we can make changes. Go sux at this.
-       ip = append(make(net.IP, 0, len(ip)), ip...)
-       mask := maskForIP(ip)
-       for i := range mask {
-               ip[i] &= mask[i]
-       }
-       r := rand & 7
-       ip[0] |= r << 5
-       return crc32.Checksum(ip[:len(mask)], crc32.MakeTable(crc32.Castagnoli))
-}
-
-// Makes a node ID secure, in-place. The ID is 20 raw bytes.
-// http://www.libtorrent.org/dht_sec.html
-func SecureNodeId(id []byte, ip net.IP) {
-       crc := crcIP(ip, id[19])
-       id[0] = byte(crc >> 24 & 0xff)
-       id[1] = byte(crc >> 16 & 0xff)
-       id[2] = byte(crc>>8&0xf8) | id[2]&7
-}
-
-// Returns whether the node ID is considered secure. The id is the 20 raw
-// bytes. http://www.libtorrent.org/dht_sec.html
-func NodeIdSecure(id string, ip net.IP) bool {
-       if len(id) != 20 {
-               panic(fmt.Sprintf("%q", id))
-       }
-       if ip4 := ip.To4(); ip4 != nil {
-               ip = ip4
-       }
-       crc := crcIP(ip, id[19])
-       if id[0] != byte(crc>>24&0xff) {
-               return false
-       }
-       if id[1] != byte(crc>>16&0xff) {
-               return false
-       }
-       if id[2]&0xf8 != byte(crc>>8&0xf8) {
-               return false
-       }
-       return true
-}
-
 type Peer struct {
        IP   net.IP
        Port int

diff --git a/dht/security.go b/dht/security.go
new file mode 100644 (file)
index 0000000..e91d160
--- /dev/null
+++ b/dht/security.go
@@ -0,0 +1,63 @@
+package dht
+
+import (
+       "fmt"
+       "hash/crc32"
+       "net"
+)
+
+func maskForIP(ip net.IP) []byte {
+       switch {
+       case ip.To4() != nil:
+               return []byte{0x03, 0x0f, 0x3f, 0xff}
+       default:
+               return []byte{0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff}
+       }
+}
+
+// Generate the CRC used to make or validate secure node ID.
+func crcIP(ip net.IP, rand uint8) uint32 {
+       if ip4 := ip.To4(); ip4 != nil {
+               ip = ip4
+       }
+       // Copy IP so we can make changes. Go sux at this.
+       ip = append(make(net.IP, 0, len(ip)), ip...)
+       mask := maskForIP(ip)
+       for i := range mask {
+               ip[i] &= mask[i]
+       }
+       r := rand & 7
+       ip[0] |= r << 5
+       return crc32.Checksum(ip[:len(mask)], crc32.MakeTable(crc32.Castagnoli))
+}
+
+// Makes a node ID secure, in-place. The ID is 20 raw bytes.
+// http://www.libtorrent.org/dht_sec.html
+func SecureNodeId(id []byte, ip net.IP) {
+       crc := crcIP(ip, id[19])
+       id[0] = byte(crc >> 24 & 0xff)
+       id[1] = byte(crc >> 16 & 0xff)
+       id[2] = byte(crc>>8&0xf8) | id[2]&7
+}
+
+// Returns whether the node ID is considered secure. The id is the 20 raw
+// bytes. http://www.libtorrent.org/dht_sec.html
+func NodeIdSecure(id string, ip net.IP) bool {
+       if len(id) != 20 {
+               panic(fmt.Sprintf("%q", id))
+       }
+       if ip4 := ip.To4(); ip4 != nil {
+               ip = ip4
+       }
+       crc := crcIP(ip, id[19])
+       if id[0] != byte(crc>>24&0xff) {
+               return false
+       }
+       if id[1] != byte(crc>>16&0xff) {
+               return false
+       }
+       if id[2]&0xf8 != byte(crc>>8&0xf8) {
+               return false
+       }
+       return true
+}