github.com/julesgoullee/go-ethereum@v1.9.7/p2p/protocol.go (about)

     1  // Copyright 2014 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 p2p
    18  
    19  import (
    20  	"fmt"
    21  
    22  	"github.com/ethereum/go-ethereum/p2p/enode"
    23  	"github.com/ethereum/go-ethereum/p2p/enr"
    24  )
    25  
    26  // Protocol represents a P2P subprotocol implementation.
    27  type Protocol struct {
    28  	// Name should contain the official protocol name,
    29  	// often a three-letter word.
    30  	Name string
    31  
    32  	// Version should contain the version number of the protocol.
    33  	Version uint
    34  
    35  	// Length should contain the number of message codes used
    36  	// by the protocol.
    37  	Length uint64
    38  
    39  	// Run is called in a new goroutine when the protocol has been
    40  	// negotiated with a peer. It should read and write messages from
    41  	// rw. The Payload for each message must be fully consumed.
    42  	//
    43  	// The peer connection is closed when Start returns. It should return
    44  	// any protocol-level error (such as an I/O error) that is
    45  	// encountered.
    46  	Run func(peer *Peer, rw MsgReadWriter) error
    47  
    48  	// NodeInfo is an optional helper method to retrieve protocol specific metadata
    49  	// about the host node.
    50  	NodeInfo func() interface{}
    51  
    52  	// PeerInfo is an optional helper method to retrieve protocol specific metadata
    53  	// about a certain peer in the network. If an info retrieval function is set,
    54  	// but returns nil, it is assumed that the protocol handshake is still running.
    55  	PeerInfo func(id enode.ID) interface{}
    56  
    57  	// DialCandidates, if non-nil, is a way to tell Server about protocol-specific nodes
    58  	// that should be dialed. The server continuously reads nodes from the iterator and
    59  	// attempts to create connections to them.
    60  	DialCandidates enode.Iterator
    61  
    62  	// Attributes contains protocol specific information for the node record.
    63  	Attributes []enr.Entry
    64  }
    65  
    66  func (p Protocol) cap() Cap {
    67  	return Cap{p.Name, p.Version}
    68  }
    69  
    70  // Cap is the structure of a peer capability.
    71  type Cap struct {
    72  	Name    string
    73  	Version uint
    74  }
    75  
    76  func (cap Cap) String() string {
    77  	return fmt.Sprintf("%s/%d", cap.Name, cap.Version)
    78  }
    79  
    80  type capsByNameAndVersion []Cap
    81  
    82  func (cs capsByNameAndVersion) Len() int      { return len(cs) }
    83  func (cs capsByNameAndVersion) Swap(i, j int) { cs[i], cs[j] = cs[j], cs[i] }
    84  func (cs capsByNameAndVersion) Less(i, j int) bool {
    85  	return cs[i].Name < cs[j].Name || (cs[i].Name == cs[j].Name && cs[i].Version < cs[j].Version)
    86  }