github.com/rawahars/moby@v24.0.4+incompatible/libnetwork/drivers/bridge/setup_ipv4.go (about)

     1  //go:build linux
     2  // +build linux
     3  
     4  package bridge
     5  
     6  import (
     7  	"errors"
     8  	"fmt"
     9  	"net"
    10  	"os"
    11  	"path/filepath"
    12  
    13  	"github.com/docker/docker/libnetwork/types"
    14  	"github.com/sirupsen/logrus"
    15  	"github.com/vishvananda/netlink"
    16  )
    17  
    18  func selectIPv4Address(addresses []netlink.Addr, selector *net.IPNet) (netlink.Addr, error) {
    19  	if len(addresses) == 0 {
    20  		return netlink.Addr{}, errors.New("unable to select an address as the address pool is empty")
    21  	}
    22  	if selector != nil {
    23  		for _, addr := range addresses {
    24  			if selector.Contains(addr.IP) {
    25  				return addr, nil
    26  			}
    27  		}
    28  	}
    29  	return addresses[0], nil
    30  }
    31  
    32  func setupBridgeIPv4(config *networkConfiguration, i *bridgeInterface) error {
    33  	if !config.InhibitIPv4 {
    34  		addrv4List, _, err := i.addresses()
    35  		if err != nil {
    36  			return fmt.Errorf("failed to retrieve bridge interface addresses: %v", err)
    37  		}
    38  
    39  		addrv4, _ := selectIPv4Address(addrv4List, config.AddressIPv4)
    40  
    41  		if !types.CompareIPNet(addrv4.IPNet, config.AddressIPv4) {
    42  			if addrv4.IPNet != nil {
    43  				if err := i.nlh.AddrDel(i.Link, &addrv4); err != nil {
    44  					return fmt.Errorf("failed to remove current ip address from bridge: %v", err)
    45  				}
    46  			}
    47  			logrus.Debugf("Assigning address to bridge interface %s: %s", config.BridgeName, config.AddressIPv4)
    48  			if err := i.nlh.AddrAdd(i.Link, &netlink.Addr{IPNet: config.AddressIPv4}); err != nil {
    49  				return &IPv4AddrAddError{IP: config.AddressIPv4, Err: err}
    50  			}
    51  		}
    52  	}
    53  
    54  	// Store bridge network and default gateway
    55  	i.bridgeIPv4 = config.AddressIPv4
    56  	i.gatewayIPv4 = config.AddressIPv4.IP
    57  
    58  	return nil
    59  }
    60  
    61  func setupGatewayIPv4(config *networkConfiguration, i *bridgeInterface) error {
    62  	if !i.bridgeIPv4.Contains(config.DefaultGatewayIPv4) {
    63  		return &ErrInvalidGateway{}
    64  	}
    65  
    66  	// Store requested default gateway
    67  	i.gatewayIPv4 = config.DefaultGatewayIPv4
    68  
    69  	return nil
    70  }
    71  
    72  func setupLoopbackAddressesRouting(config *networkConfiguration, i *bridgeInterface) error {
    73  	sysPath := filepath.Join("/proc/sys/net/ipv4/conf", config.BridgeName, "route_localnet")
    74  	ipv4LoRoutingData, err := os.ReadFile(sysPath)
    75  	if err != nil {
    76  		return fmt.Errorf("Cannot read IPv4 local routing setup: %v", err)
    77  	}
    78  	// Enable loopback addresses routing only if it isn't already enabled
    79  	if ipv4LoRoutingData[0] != '1' {
    80  		if err := os.WriteFile(sysPath, []byte{'1', '\n'}, 0644); err != nil {
    81  			return fmt.Errorf("Unable to enable local routing for hairpin mode: %v", err)
    82  		}
    83  	}
    84  	return nil
    85  }