github.com/rish1988/moby@v25.0.2+incompatible/libnetwork/drivers/bridge/setup_ipv6_linux.go (about)

     1  package bridge
     2  
     3  import (
     4  	"context"
     5  	"fmt"
     6  	"net"
     7  	"os"
     8  
     9  	"github.com/containerd/log"
    10  	"github.com/vishvananda/netlink"
    11  )
    12  
    13  // bridgeIPv6 is the default, link-local IPv6 address for the bridge (fe80::1/64)
    14  var bridgeIPv6 = &net.IPNet{IP: net.ParseIP("fe80::1"), Mask: net.CIDRMask(64, 128)}
    15  
    16  const (
    17  	ipv6ForwardConfPerm    = 0o644
    18  	ipv6ForwardConfDefault = "/proc/sys/net/ipv6/conf/default/forwarding"
    19  	ipv6ForwardConfAll     = "/proc/sys/net/ipv6/conf/all/forwarding"
    20  )
    21  
    22  func setupBridgeIPv6(config *networkConfiguration, i *bridgeInterface) error {
    23  	procFile := "/proc/sys/net/ipv6/conf/" + config.BridgeName + "/disable_ipv6"
    24  	ipv6BridgeData, err := os.ReadFile(procFile)
    25  	if err != nil {
    26  		return fmt.Errorf("Cannot read IPv6 setup for bridge %v: %v", config.BridgeName, err)
    27  	}
    28  	// Enable IPv6 on the bridge only if it isn't already enabled
    29  	if ipv6BridgeData[0] != '0' {
    30  		if err := os.WriteFile(procFile, []byte{'0', '\n'}, ipv6ForwardConfPerm); err != nil {
    31  			return fmt.Errorf("Unable to enable IPv6 addresses on bridge: %v", err)
    32  		}
    33  	}
    34  
    35  	// Remove unwanted addresses from the bridge, add required addresses, and assign
    36  	// values to "i.bridgeIPv6", "i.gatewayIPv6".
    37  	if err := i.programIPv6Addresses(config); err != nil {
    38  		return err
    39  	}
    40  
    41  	// Setting route to global IPv6 subnet
    42  	log.G(context.TODO()).Debugf("Adding route to IPv6 network %s via device %s", config.AddressIPv6.String(), config.BridgeName)
    43  	err = i.nlh.RouteAdd(&netlink.Route{
    44  		Scope:     netlink.SCOPE_UNIVERSE,
    45  		LinkIndex: i.Link.Attrs().Index,
    46  		Dst:       config.AddressIPv6,
    47  	})
    48  	if err != nil && !os.IsExist(err) {
    49  		log.G(context.TODO()).Errorf("Could not add route to IPv6 network %s via device %s: %s", config.AddressIPv6.String(), config.BridgeName, err)
    50  	}
    51  
    52  	return nil
    53  }
    54  
    55  func setupGatewayIPv6(config *networkConfiguration, i *bridgeInterface) error {
    56  	if !config.AddressIPv6.Contains(config.DefaultGatewayIPv6) {
    57  		return &ErrInvalidGateway{}
    58  	}
    59  
    60  	// Store requested default gateway
    61  	i.gatewayIPv6 = config.DefaultGatewayIPv6
    62  
    63  	return nil
    64  }
    65  
    66  func setupIPv6Forwarding(config *networkConfiguration, i *bridgeInterface) error {
    67  	// Get current IPv6 default forwarding setup
    68  	ipv6ForwardDataDefault, err := os.ReadFile(ipv6ForwardConfDefault)
    69  	if err != nil {
    70  		return fmt.Errorf("Cannot read IPv6 default forwarding setup: %v", err)
    71  	}
    72  	// Enable IPv6 default forwarding only if it is not already enabled
    73  	if ipv6ForwardDataDefault[0] != '1' {
    74  		if err := os.WriteFile(ipv6ForwardConfDefault, []byte{'1', '\n'}, ipv6ForwardConfPerm); err != nil {
    75  			log.G(context.TODO()).Warnf("Unable to enable IPv6 default forwarding: %v", err)
    76  		}
    77  	}
    78  
    79  	// Get current IPv6 all forwarding setup
    80  	ipv6ForwardDataAll, err := os.ReadFile(ipv6ForwardConfAll)
    81  	if err != nil {
    82  		return fmt.Errorf("Cannot read IPv6 all forwarding setup: %v", err)
    83  	}
    84  	// Enable IPv6 all forwarding only if it is not already enabled
    85  	if ipv6ForwardDataAll[0] != '1' {
    86  		if err := os.WriteFile(ipv6ForwardConfAll, []byte{'1', '\n'}, ipv6ForwardConfPerm); err != nil {
    87  			log.G(context.TODO()).Warnf("Unable to enable IPv6 all forwarding: %v", err)
    88  		}
    89  	}
    90  
    91  	return nil
    92  }