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moby--moby/libnetwork/drivers/bridge/setup_ipv4.go

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package bridge
import (
"fmt"
"io/ioutil"
"net"
"path/filepath"
log "github.com/Sirupsen/logrus"
"github.com/docker/libnetwork/netutils"
"github.com/vishvananda/netlink"
)
var bridgeNetworks []*net.IPNet
func init() {
// Here we don't follow the convention of using the 1st IP of the range for the gateway.
// This is to use the same gateway IPs as the /24 ranges, which predate the /16 ranges.
// In theory this shouldn't matter - in practice there's bound to be a few scripts relying
// on the internal addressing or other stupid things like that.
// They shouldn't, but hey, let's not break them unless we really have to.
for _, addr := range []string{
"172.17.42.1/16", // Don't use 172.16.0.0/16, it conflicts with EC2 DNS 172.16.0.23
"10.0.42.1/16", // Don't even try using the entire /8, that's too intrusive
"10.1.42.1/16",
"10.42.42.1/16",
"172.16.42.1/24",
"172.16.43.1/24",
"172.16.44.1/24",
"10.0.42.1/24",
"10.0.43.1/24",
"192.168.42.1/24",
"192.168.43.1/24",
"192.168.44.1/24",
} {
ip, net, err := net.ParseCIDR(addr)
if err != nil {
log.Errorf("Failed to parse address %s", addr)
continue
}
net.IP = ip.To4()
bridgeNetworks = append(bridgeNetworks, net)
}
}
func setupBridgeIPv4(config *NetworkConfiguration, i *bridgeInterface) error {
addrv4, _, err := i.addresses()
if err != nil {
return err
}
// Check if we have an IP address already on the bridge.
if addrv4.IPNet != nil {
// Make sure to store bridge network and default gateway before getting out.
i.bridgeIPv4 = addrv4.IPNet
i.gatewayIPv4 = addrv4.IPNet.IP
return nil
}
// Do not try to configure IPv4 on a non-default bridge unless you are
// specifically asked to do so.
if config.BridgeName != DefaultBridgeName && !config.AllowNonDefaultBridge {
return NonDefaultBridgeExistError(config.BridgeName)
}
bridgeIPv4, err := electBridgeIPv4(config)
if err != nil {
return err
}
log.Debugf("Creating bridge interface %q with network %s", config.BridgeName, bridgeIPv4)
if err := netlink.AddrAdd(i.Link, &netlink.Addr{IPNet: bridgeIPv4}); err != nil {
return &IPv4AddrAddError{IP: bridgeIPv4, Err: err}
}
// Store bridge network and default gateway
i.bridgeIPv4 = bridgeIPv4
i.gatewayIPv4 = i.bridgeIPv4.IP
return nil
}
func allocateBridgeIP(config *NetworkConfiguration, i *bridgeInterface) error {
ipAllocator.RequestIP(i.bridgeIPv4, i.bridgeIPv4.IP)
return nil
}
func electBridgeIPv4(config *NetworkConfiguration) (*net.IPNet, error) {
// Use the requested IPv4 CIDR when available.
if config.AddressIPv4 != nil {
return config.AddressIPv4, nil
}
// We don't check for an error here, because we don't really care if we
// can't read /etc/resolv.conf. So instead we skip the append if resolvConf
// is nil. It either doesn't exist, or we can't read it for some reason.
nameservers := []string{}
if resolvConf, _ := readResolvConf(); resolvConf != nil {
nameservers = append(nameservers, getNameserversAsCIDR(resolvConf)...)
}
// Try to automatically elect appropriate bridge IPv4 settings.
for _, n := range bridgeNetworks {
if err := netutils.CheckNameserverOverlaps(nameservers, n); err == nil {
if err := netutils.CheckRouteOverlaps(n); err == nil {
return n, nil
}
}
}
return nil, IPv4AddrRangeError(config.BridgeName)
}
func setupGatewayIPv4(config *NetworkConfiguration, i *bridgeInterface) error {
if !i.bridgeIPv4.Contains(config.DefaultGatewayIPv4) {
return &ErrInvalidGateway{}
}
if _, err := ipAllocator.RequestIP(i.bridgeIPv4, config.DefaultGatewayIPv4); err != nil {
return err
}
// Store requested default gateway
i.gatewayIPv4 = config.DefaultGatewayIPv4
return nil
}
func setupLoopbackAdressesRouting(config *NetworkConfiguration, i *bridgeInterface) error {
// Enable loopback adresses routing
sysPath := filepath.Join("/proc/sys/net/ipv4/conf", config.BridgeName, "route_localnet")
if err := ioutil.WriteFile(sysPath, []byte{'1', '\n'}, 0644); err != nil {
return fmt.Errorf("Unable to enable local routing for hairpin mode: %v", err)
}
return nil
}