github.com/core-coin/go-core/v2@v2.1.9/p2p/discover/common.go (about)

     1  // Copyright 2019 by the Authors
     2  // This file is part of the go-core library.
     3  //
     4  // The go-core 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-core 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-core library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package discover
    18  
    19  import (
    20  	"net"
    21  
    22  	"github.com/core-coin/go-core/v2/common/mclock"
    23  	"github.com/core-coin/go-core/v2/crypto"
    24  	"github.com/core-coin/go-core/v2/log"
    25  	"github.com/core-coin/go-core/v2/p2p/enode"
    26  	"github.com/core-coin/go-core/v2/p2p/enr"
    27  	"github.com/core-coin/go-core/v2/p2p/netutil"
    28  )
    29  
    30  // UDPConn is a network connection on which discovery can operate.
    31  type UDPConn interface {
    32  	ReadFromUDP(b []byte) (n int, addr *net.UDPAddr, err error)
    33  	WriteToUDP(b []byte, addr *net.UDPAddr) (n int, err error)
    34  	Close() error
    35  	LocalAddr() net.Addr
    36  }
    37  
    38  // Config holds settings for the discovery listener.
    39  type Config struct {
    40  	// These settings are required and configure the UDP listener:
    41  	PrivateKey *crypto.PrivateKey
    42  
    43  	// These settings are optional:
    44  	NetRestrict  *netutil.Netlist   // network whitelist
    45  	Bootnodes    []*enode.Node      // list of bootstrap nodes
    46  	Unhandled    chan<- ReadPacket  // unhandled packets are sent on this channel
    47  	Log          log.Logger         // if set, log messages go here
    48  	ValidSchemes enr.IdentityScheme // allowed identity schemes
    49  	Clock        mclock.Clock
    50  }
    51  
    52  func (cfg Config) withDefaults() Config {
    53  	if cfg.Log == nil {
    54  		cfg.Log = log.Root()
    55  	}
    56  	if cfg.ValidSchemes == nil {
    57  		cfg.ValidSchemes = enode.ValidSchemes
    58  	}
    59  	if cfg.Clock == nil {
    60  		cfg.Clock = mclock.System{}
    61  	}
    62  	return cfg
    63  }
    64  
    65  // ListenUDP starts listening for discovery packets on the given UDP socket.
    66  func ListenUDP(c UDPConn, ln *enode.LocalNode, cfg Config) (*UDPv4, error) {
    67  	return ListenV4(c, ln, cfg)
    68  }
    69  
    70  // ReadPacket is a packet that couldn't be handled. Those packets are sent to the unhandled
    71  // channel if configured.
    72  type ReadPacket struct {
    73  	Data []byte
    74  	Addr *net.UDPAddr
    75  }
    76  
    77  func min(x, y int) int {
    78  	if x > y {
    79  		return y
    80  	}
    81  	return x
    82  }