github.com/gitbundle/modules@v0.0.0-20231025071548-85b91c5c3b01/hostmatcher/http.go (about)

     1  // Copyright 2023 The GitBundle Inc. All rights reserved.
     2  // Copyright 2017 The Gitea Authors. All rights reserved.
     3  // Use of this source code is governed by a MIT-style
     4  // license that can be found in the LICENSE file.
     5  
     6  package hostmatcher
     7  
     8  import (
     9  	"context"
    10  	"fmt"
    11  	"net"
    12  	"syscall"
    13  	"time"
    14  )
    15  
    16  // NewDialContext returns a DialContext for Transport, the DialContext will do allow/block list check
    17  func NewDialContext(usage string, allowList, blockList *HostMatchList) func(ctx context.Context, network, addr string) (net.Conn, error) {
    18  	// How Go HTTP Client works with redirection:
    19  	//   transport.RoundTrip URL=http://domain.com, Host=domain.com
    20  	//   transport.DialContext addrOrHost=domain.com:80
    21  	//   dialer.Control tcp4:11.22.33.44:80
    22  	//   transport.RoundTrip URL=http://www.domain.com/, Host=(empty here, in the direction, HTTP client doesn't fill the Host field)
    23  	//   transport.DialContext addrOrHost=domain.com:80
    24  	//   dialer.Control tcp4:11.22.33.44:80
    25  	return func(ctx context.Context, network, addrOrHost string) (net.Conn, error) {
    26  		dialer := net.Dialer{
    27  			// default values comes from http.DefaultTransport
    28  			Timeout:   30 * time.Second,
    29  			KeepAlive: 30 * time.Second,
    30  
    31  			Control: func(network, ipAddr string, c syscall.RawConn) (err error) {
    32  				var host string
    33  				if host, _, err = net.SplitHostPort(addrOrHost); err != nil {
    34  					return err
    35  				}
    36  				// in Control func, the addr was already resolved to IP:PORT format, there is no cost to do ResolveTCPAddr here
    37  				tcpAddr, err := net.ResolveTCPAddr(network, ipAddr)
    38  				if err != nil {
    39  					return fmt.Errorf("%s can only call HTTP servers via TCP, deny '%s(%s:%s)', err=%v", usage, host, network, ipAddr, err)
    40  				}
    41  
    42  				var blockedError error
    43  				if blockList.MatchHostOrIP(host, tcpAddr.IP) {
    44  					blockedError = fmt.Errorf("%s can not call blocked HTTP servers (check your %s setting), deny '%s(%s)'", usage, blockList.SettingKeyHint, host, ipAddr)
    45  				}
    46  
    47  				// if we have an allow-list, check the allow-list first
    48  				if !allowList.IsEmpty() {
    49  					if !allowList.MatchHostOrIP(host, tcpAddr.IP) {
    50  						return fmt.Errorf("%s can only call allowed HTTP servers (check your %s setting), deny '%s(%s)'", usage, allowList.SettingKeyHint, host, ipAddr)
    51  					}
    52  				}
    53  				// otherwise, we always follow the blocked list
    54  				return blockedError
    55  			},
    56  		}
    57  		return dialer.DialContext(ctx, network, addrOrHost)
    58  	}
    59  }