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Implement IP 4 to 6 mapping on HostIP listen addresses #50

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30 changes: 29 additions & 1 deletion cmd/docker-ipv6nat/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ import (
"fmt"
"log"
"os"
"strings"
"net"

"github.com/fsouza/go-dockerclient"
"github.com/robbertkl/docker-ipv6nat"
Expand All @@ -18,6 +20,7 @@ var (
userlandProxy bool
version bool
debug bool
mapIpv4 string
)

func usage() {
Expand All @@ -43,6 +46,7 @@ func initFlags() {
flag.BoolVar(&retry, "retry", false, "keep retrying to reconnect after a disconnect")
flag.BoolVar(&version, "version", false, "show version")
flag.BoolVar(&debug, "debug", false, "log ruleset changes to stdout")
flag.StringVar(&mapIpv4, "map-ipv4", "", "IPv4 listen address mapping (IPV4/CIDR=IPV4,...)")

flag.Usage = usage
flag.Parse()
Expand All @@ -66,6 +70,25 @@ func main() {
}
}

func parseIpMapping(mapIpv4 string) (map[*net.IPNet]net.IP, error) {
res := map[*net.IPNet]net.IP{}
for _, map46 := range strings.Split(mapIpv4, ",") {
s := strings.Split(map46, "=")
if len(s)==2 && s[0] != "" && s[1] != "" {
_, ip4, err := net.ParseCIDR(s[0])
if err != nil {
return nil, fmt.Errorf("Cannot parse %+v IPv4, %e", map46, err)
}
ip6 := net.ParseIP(s[1])
if ip6 == nil {
return nil, fmt.Errorf("Cannot parse %+v IPv6, %e", map46)
}
res[ip4] = ip6
}
}
return res, nil
}

func run() error {
if debug {
log.Println("docker-ipv6nat is running in debug mode")
Expand All @@ -76,7 +99,12 @@ func run() error {
return err
}

state, err := dockeripv6nat.NewState(debug)
ipMap, err := parseIpMapping(mapIpv4)
if err != nil {
return err
}

state, err := dockeripv6nat.NewState(debug, ipMap)
if err != nil {
return err
}
Expand Down
15 changes: 14 additions & 1 deletion state.go
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@ type State struct {
manager *Manager
networks map[string]*managedNetwork
containers map[string]*managedContainer
mapIpv4 map[*net.IPNet]net.IP
debug bool
}

// fc00::/7, Unique Local IPv6 Unicast Addresses, see RFC 4193
Expand All @@ -22,7 +24,7 @@ var ulaCIDR = net.IPNet{
}

// NewState constructs a new state
func NewState(debug bool) (*State, error) {
func NewState(debug bool, mapIpv4 map[*net.IPNet]net.IP) (*State, error) {
manager, err := NewManager(debug)
if err != nil {
return nil, err
Expand All @@ -32,6 +34,7 @@ func NewState(debug bool) (*State, error) {
manager: manager,
networks: make(map[string]*managedNetwork),
containers: make(map[string]*managedContainer),
mapIpv4: mapIpv4,
}, nil
}

Expand Down Expand Up @@ -236,6 +239,16 @@ func (s *State) parseContainer(container *docker.Container) *managedContainer {

if binding.HostIP != "" && binding.HostIP != "0.0.0.0" {
ip := net.ParseIP(binding.HostIP)
if ip != nil && ip.To4() != nil {
// Try map Ipv4 to IPv6
for ip4net, ip6 := range s.mapIpv4 {
if ip4net.Contains(ip) {
log.Printf("Converting listen IP %v to %v (matching %v)", ip, ip6, ip4net)
ip = ip6
break
}
}
}
if ip == nil || ip.To4() != nil {
// Skip bindings to IPv4.
continue
Expand Down