github.com/theQRL/go-zond@v0.1.1/p2p/discover/common.go (about)

     1  // Copyright 2019 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package discover
    18  
    19  import (
    20  	"crypto/ecdsa"
    21  	"net"
    22  	"time"
    23  
    24  	"github.com/theQRL/go-zond/common/mclock"
    25  	"github.com/theQRL/go-zond/log"
    26  	"github.com/theQRL/go-zond/p2p/enode"
    27  	"github.com/theQRL/go-zond/p2p/enr"
    28  	"github.com/theQRL/go-zond/p2p/netutil"
    29  )
    30  
    31  // UDPConn is a network connection on which discovery can operate.
    32  type UDPConn interface {
    33  	ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error)
    34  	WriteToUDP(b []byte, addr *net.UDPAddr) (n int, err error)
    35  	Close() error
    36  	LocalAddr() net.Addr
    37  }
    38  
    39  // Config holds settings for the discovery listener.
    40  type Config struct {
    41  	// These settings are required and configure the UDP listener:
    42  	PrivateKey *ecdsa.PrivateKey
    43  
    44  	// All remaining settings are optional.
    45  
    46  	// Packet handling configuration:
    47  	NetRestrict *netutil.Netlist  // list of allowed IP networks
    48  	Unhandled   chan<- ReadPacket // unhandled packets are sent on this channel
    49  
    50  	// Node table configuration:
    51  	Bootnodes       []*enode.Node // list of bootstrap nodes
    52  	PingInterval    time.Duration // speed of node liveness check
    53  	RefreshInterval time.Duration // used in bucket refresh
    54  
    55  	// The options below are useful in very specific cases, like in unit tests.
    56  	V5ProtocolID *[6]byte
    57  	Log          log.Logger         // if set, log messages go here
    58  	ValidSchemes enr.IdentityScheme // allowed identity schemes
    59  	Clock        mclock.Clock
    60  }
    61  
    62  func (cfg Config) withDefaults() Config {
    63  	// Node table configuration:
    64  	if cfg.PingInterval == 0 {
    65  		cfg.PingInterval = 10 * time.Second
    66  	}
    67  	if cfg.RefreshInterval == 0 {
    68  		cfg.RefreshInterval = 30 * time.Minute
    69  	}
    70  
    71  	// Debug/test settings:
    72  	if cfg.Log == nil {
    73  		cfg.Log = log.Root()
    74  	}
    75  	if cfg.ValidSchemes == nil {
    76  		cfg.ValidSchemes = enode.ValidSchemes
    77  	}
    78  	if cfg.Clock == nil {
    79  		cfg.Clock = mclock.System{}
    80  	}
    81  	return cfg
    82  }
    83  
    84  // ListenUDP starts listening for discovery packets on the given UDP socket.
    85  func ListenUDP(c UDPConn, ln *enode.LocalNode, cfg Config) (*UDPv4, error) {
    86  	return ListenV4(c, ln, cfg)
    87  }
    88  
    89  // ReadPacket is a packet that couldn't be handled. Those packets are sent to the unhandled
    90  // channel if configured.
    91  type ReadPacket struct {
    92  	Data []byte
    93  	Addr *net.UDPAddr
    94  }
    95  
    96  func min(x, y int) int {
    97  	if x > y {
    98  		return y
    99  	}
   100  	return x
   101  }