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362 lines (312 loc) · 7.82 KB
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Copy pathchain.go
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362 lines (312 loc) · 7.82 KB
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package gost
import (
"context"
"errors"
"net"
"time"
"github.com/go-log/log"
)
var (
// ErrEmptyChain is an error that implies the chain is empty.
ErrEmptyChain = errors.New("empty chain")
)
// Chain is a proxy chain that holds a list of proxy node groups.
type Chain struct {
isRoute bool
Retries int
nodeGroups []*NodeGroup
route []Node // nodes in the selected route
}
// NewChain creates a proxy chain with a list of proxy nodes.
// It creates the node groups automatically, one group per node.
func NewChain(nodes ...Node) *Chain {
chain := &Chain{}
for _, node := range nodes {
chain.nodeGroups = append(chain.nodeGroups, NewNodeGroup(node))
}
return chain
}
// newRoute creates a chain route.
// a chain route is the final route after node selection.
func newRoute(nodes ...Node) *Chain {
chain := NewChain(nodes...)
chain.isRoute = true
return chain
}
// Nodes returns the proxy nodes that the chain holds.
// The first node in each group will be returned.
func (c *Chain) Nodes() (nodes []Node) {
for _, group := range c.nodeGroups {
if ns := group.Nodes(); len(ns) > 0 {
nodes = append(nodes, ns[0])
}
}
return
}
// NodeGroups returns the list of node group.
func (c *Chain) NodeGroups() []*NodeGroup {
return c.nodeGroups
}
// LastNode returns the last node of the node list.
// If the chain is empty, an empty node will be returned.
// If the last node is a node group, the first node in the group will be returned.
func (c *Chain) LastNode() Node {
if c.IsEmpty() {
return Node{}
}
group := c.nodeGroups[len(c.nodeGroups)-1]
return group.GetNode(0)
}
// LastNodeGroup returns the last group of the group list.
func (c *Chain) LastNodeGroup() *NodeGroup {
if c.IsEmpty() {
return nil
}
return c.nodeGroups[len(c.nodeGroups)-1]
}
// AddNode appends the node(s) to the chain.
func (c *Chain) AddNode(nodes ...Node) {
if c == nil {
return
}
for _, node := range nodes {
c.nodeGroups = append(c.nodeGroups, NewNodeGroup(node))
}
}
// AddNodeGroup appends the group(s) to the chain.
func (c *Chain) AddNodeGroup(groups ...*NodeGroup) {
if c == nil {
return
}
for _, group := range groups {
c.nodeGroups = append(c.nodeGroups, group)
}
}
// IsEmpty checks if the chain is empty.
// An empty chain means that there is no proxy node or node group in the chain.
func (c *Chain) IsEmpty() bool {
return c == nil || len(c.nodeGroups) == 0
}
// Dial connects to the target TCP address addr through the chain.
// Deprecated: use DialContext instead.
func (c *Chain) Dial(address string, opts ...ChainOption) (conn net.Conn, err error) {
return c.DialContext(context.Background(), "tcp", address, opts...)
}
// DialContext connects to the address on the named network using the provided context.
func (c *Chain) DialContext(ctx context.Context, network, address string, opts ...ChainOption) (conn net.Conn, err error) {
options := &ChainOptions{}
for _, opt := range opts {
opt(options)
}
retries := 1
if c != nil && c.Retries > 0 {
retries = c.Retries
}
if options.Retries > 0 {
retries = options.Retries
}
for i := 0; i < retries; i++ {
conn, err = c.dialWithOptions(ctx, network, address, options)
if err == nil {
break
}
}
return
}
func (c *Chain) dialWithOptions(ctx context.Context, network, address string, options *ChainOptions) (net.Conn, error) {
if options == nil {
options = &ChainOptions{}
}
route, err := c.selectRouteFor(address)
if err != nil {
return nil, err
}
ipAddr := address
if address != "" {
ipAddr = c.resolve(address, options.Resolver, options.Hosts)
}
timeout := options.Timeout
if timeout <= 0 {
timeout = DialTimeout
}
if route.IsEmpty() {
switch network {
case "udp", "udp4", "udp6":
if address == "" {
return net.ListenUDP(network, nil)
}
default:
}
d := &net.Dialer{
Timeout: timeout,
// LocalAddr: laddr, // TODO: optional local address
}
return d.DialContext(ctx, network, ipAddr)
}
conn, err := route.getConn(ctx)
if err != nil {
return nil, err
}
cOpts := append([]ConnectOption{AddrConnectOption(address)}, route.LastNode().ConnectOptions...)
cc, err := route.LastNode().Client.ConnectContext(ctx, conn, network, ipAddr, cOpts...)
if err != nil {
conn.Close()
return nil, err
}
return cc, nil
}
func (*Chain) resolve(addr string, resolver Resolver, hosts *Hosts) string {
host, port, err := net.SplitHostPort(addr)
if err != nil {
return addr
}
if ip := hosts.Lookup(host); ip != nil {
return net.JoinHostPort(ip.String(), port)
}
if resolver != nil {
ips, err := resolver.Resolve(host)
if err != nil {
log.Logf("[resolver] %s: %v", host, err)
}
if len(ips) > 0 {
return net.JoinHostPort(ips[0].String(), port)
}
}
return addr
}
// Conn obtains a handshaked connection to the last node of the chain.
func (c *Chain) Conn(opts ...ChainOption) (conn net.Conn, err error) {
options := &ChainOptions{}
for _, opt := range opts {
opt(options)
}
ctx := context.Background()
retries := 1
if c != nil && c.Retries > 0 {
retries = c.Retries
}
if options.Retries > 0 {
retries = options.Retries
}
for i := 0; i < retries; i++ {
var route *Chain
route, err = c.selectRoute()
if err != nil {
continue
}
conn, err = route.getConn(ctx)
if err == nil {
break
}
}
return
}
// getConn obtains a connection to the last node of the chain.
func (c *Chain) getConn(ctx context.Context) (conn net.Conn, err error) {
if c.IsEmpty() {
err = ErrEmptyChain
return
}
nodes := c.Nodes()
node := nodes[0]
cc, err := node.Client.Dial(node.Addr, node.DialOptions...)
if err != nil {
node.MarkDead()
return
}
cn, err := node.Client.Handshake(cc, node.HandshakeOptions...)
if err != nil {
cc.Close()
node.MarkDead()
return
}
node.ResetDead()
preNode := node
for _, node := range nodes[1:] {
var cc net.Conn
cc, err = preNode.Client.ConnectContext(ctx, cn, "tcp", node.Addr, preNode.ConnectOptions...)
if err != nil {
cn.Close()
node.MarkDead()
return
}
cc, err = node.Client.Handshake(cc, node.HandshakeOptions...)
if err != nil {
cn.Close()
node.MarkDead()
return
}
node.ResetDead()
cn = cc
preNode = node
}
conn = cn
return
}
func (c *Chain) selectRoute() (route *Chain, err error) {
return c.selectRouteFor("")
}
// selectRouteFor selects route with bypass testing.
func (c *Chain) selectRouteFor(addr string) (route *Chain, err error) {
if c.IsEmpty() {
return newRoute(), nil
}
if c.isRoute {
return c, nil
}
route = newRoute()
var nl []Node
for _, group := range c.nodeGroups {
var node Node
node, err = group.Next()
if err != nil {
return
}
if node.Bypass.Contains(addr) {
break
}
if node.Client.Transporter.Multiplex() {
node.DialOptions = append(node.DialOptions,
ChainDialOption(route),
)
route = newRoute() // cutoff the chain for multiplex node.
}
route.AddNode(node)
nl = append(nl, node)
}
route.route = nl
return
}
// ChainOptions holds options for Chain.
type ChainOptions struct {
Retries int
Timeout time.Duration
Hosts *Hosts
Resolver Resolver
}
// ChainOption allows a common way to set chain options.
type ChainOption func(opts *ChainOptions)
// RetryChainOption specifies the times of retry used by Chain.Dial.
func RetryChainOption(retries int) ChainOption {
return func(opts *ChainOptions) {
opts.Retries = retries
}
}
// TimeoutChainOption specifies the timeout used by Chain.Dial.
func TimeoutChainOption(timeout time.Duration) ChainOption {
return func(opts *ChainOptions) {
opts.Timeout = timeout
}
}
// HostsChainOption specifies the hosts used by Chain.Dial.
func HostsChainOption(hosts *Hosts) ChainOption {
return func(opts *ChainOptions) {
opts.Hosts = hosts
}
}
// ResolverChainOption specifies the Resolver used by Chain.Dial.
func ResolverChainOption(resolver Resolver) ChainOption {
return func(opts *ChainOptions) {
opts.Resolver = resolver
}
}