dotcloud/docker

package bridge

import (
    "context"
    "fmt"
    "net/netip"
    "os"

    "github.com/containerd/log"
)

// Standard link local prefix
var linkLocalPrefix = netip.MustParsePrefix("fe80::/64")

const (
    ipv6ForwardConfPerm    = 0o644
    ipv6ForwardConfDefault = "/proc/sys/net/ipv6/conf/default/forwarding"
    ipv6ForwardConfAll     = "/proc/sys/net/ipv6/conf/all/forwarding"
)

func setupBridgeIPv6(config *networkConfiguration, i *bridgeInterface) error {
    procFile := "/proc/sys/net/ipv6/conf/" + config.BridgeName + "/disable_ipv6"
    ipv6BridgeData, err := os.ReadFile(procFile)
    if err != nil {
        return fmt.Errorf("Cannot read IPv6 setup for bridge %v: %v", config.BridgeName, err)
    }
    // Enable IPv6 on the bridge only if it isn't already enabled
    if ipv6BridgeData[0] != '0' {
        if err := os.WriteFile(procFile, []byte{'0', '\n'}, ipv6ForwardConfPerm); err != nil {
            return fmt.Errorf("Unable to enable IPv6 addresses on bridge: %v", err)
        }
    }

    // Remove unwanted addresses from the bridge, add required addresses, and assign
    // values to "i.bridgeIPv6", "i.gatewayIPv6".
    if err := i.programIPv6Addresses(config); err != nil {
        return err
    }
    return nil
}

func setupGatewayIPv6(config *networkConfiguration, i *bridgeInterface) error {
    if !config.AddressIPv6.Contains(config.DefaultGatewayIPv6) {
        return &ErrInvalidGateway{}
    }

    // Store requested default gateway
    i.gatewayIPv6 = config.DefaultGatewayIPv6

    return nil
}

func setupIPv6Forwarding(config *networkConfiguration, i *bridgeInterface) error {
    // Get current IPv6 default forwarding setup
    ipv6ForwardDataDefault, err := os.ReadFile(ipv6ForwardConfDefault)
    if err != nil {
        return fmt.Errorf("Cannot read IPv6 default forwarding setup: %v", err)
    }
    // Enable IPv6 default forwarding only if it is not already enabled
    if ipv6ForwardDataDefault[0] != '1' {
        if err := os.WriteFile(ipv6ForwardConfDefault, []byte{'1', '\n'}, ipv6ForwardConfPerm); err != nil {
            log.G(context.TODO()).Warnf("Unable to enable IPv6 default forwarding: %v", err)
        }
    }

    // Get current IPv6 all forwarding setup
    ipv6ForwardDataAll, err := os.ReadFile(ipv6ForwardConfAll)
    if err != nil {
        return fmt.Errorf("Cannot read IPv6 all forwarding setup: %v", err)
    }
    // Enable IPv6 all forwarding only if it is not already enabled
    if ipv6ForwardDataAll[0] != '1' {
        if err := os.WriteFile(ipv6ForwardConfAll, []byte{'1', '\n'}, ipv6ForwardConfPerm); err != nil {
            log.G(context.TODO()).Warnf("Unable to enable IPv6 all forwarding: %v", err)
        }
    }

    return nil
}