docker/docker

//go:build linux

package ipvlan

import (
    "context"
    "fmt"
    "net"

    "github.com/containerd/log"
    "github.com/docker/docker/libnetwork/driverapi"
    "github.com/docker/docker/libnetwork/netutils"
    "github.com/docker/docker/libnetwork/ns"
    "github.com/docker/docker/libnetwork/types"
)

type staticRoute struct {
    Destination *net.IPNet
    RouteType   int
    NextHop     net.IP
}

const (
    defaultV4RouteCidr = "0.0.0.0/0"
    defaultV6RouteCidr = "::/0"
)

// Join method is invoked when a Sandbox is attached to an endpoint.
func (d *driver) Join(nid, eid string, sboxKey string, jinfo driverapi.JoinInfo, options map[string]interface{}) error {
    n, err := d.getNetwork(nid)
    if err != nil {
        return err
    }
    endpoint := n.endpoint(eid)
    if endpoint == nil {
        return fmt.Errorf("could not find endpoint with id %s", eid)
    }
    // generate a name for the iface that will be renamed to eth0 in the sbox
    containerIfName, err := netutils.GenerateIfaceName(ns.NlHandle(), vethPrefix, vethLen)
    if err != nil {
        return fmt.Errorf("error generating an interface name: %v", err)
    }
    // create the netlink ipvlan interface
    vethName, err := createIPVlan(containerIfName, n.config.Parent, n.config.IpvlanMode, n.config.IpvlanFlag)
    if err != nil {
        return err
    }
    // bind the generated iface name to the endpoint
    endpoint.srcName = vethName
    ep := n.endpoint(eid)
    if ep == nil {
        return fmt.Errorf("could not find endpoint with id %s", eid)
    }
    if !n.config.Internal {
        switch n.config.IpvlanMode {
        case modeL3, modeL3S:
            // disable gateway services to add a default gw using dev eth0 only
            jinfo.DisableGatewayService()
            defaultRoute, err := ifaceGateway(defaultV4RouteCidr)
            if err != nil {
                return err
            }
            if err := jinfo.AddStaticRoute(defaultRoute.Destination, defaultRoute.RouteType, defaultRoute.NextHop); err != nil {
                return fmt.Errorf("failed to set an ipvlan l3/l3s mode ipv4 default gateway: %v", err)
            }
            log.G(context.TODO()).Debugf("Ipvlan Endpoint Joined with IPv4_Addr: %s, Ipvlan_Mode: %s, Parent: %s",
                ep.addr.IP.String(), n.config.IpvlanMode, n.config.Parent)
            // If the endpoint has a v6 address, set a v6 default route
            if ep.addrv6 != nil {
                default6Route, err := ifaceGateway(defaultV6RouteCidr)
                if err != nil {
                    return err
                }
                if err = jinfo.AddStaticRoute(default6Route.Destination, default6Route.RouteType, default6Route.NextHop); err != nil {
                    return fmt.Errorf("failed to set an ipvlan l3/l3s mode ipv6 default gateway: %v", err)
                }
                log.G(context.TODO()).Debugf("Ipvlan Endpoint Joined with IPv6_Addr: %s, Ipvlan_Mode: %s, Parent: %s",
                    ep.addrv6.IP.String(), n.config.IpvlanMode, n.config.Parent)
            }
        case modeL2:
            // parse and correlate the endpoint v4 address with the available v4 subnets
            if len(n.config.Ipv4Subnets) > 0 {
                s := n.getSubnetforIPv4(ep.addr)
                if s == nil {
                    return fmt.Errorf("could not find a valid ipv4 subnet for endpoint %s", eid)
                }
                v4gw, _, err := net.ParseCIDR(s.GwIP)
                if err != nil {
                    return fmt.Errorf("gateway %s is not a valid ipv4 address: %v", s.GwIP, err)
                }
                err = jinfo.SetGateway(v4gw)
                if err != nil {
                    return err
                }
                log.G(context.TODO()).Debugf("Ipvlan Endpoint Joined with IPv4_Addr: %s, Gateway: %s, Ipvlan_Mode: %s, Parent: %s",
                    ep.addr.IP.String(), v4gw.String(), n.config.IpvlanMode, n.config.Parent)
            }
            // parse and correlate the endpoint v6 address with the available v6 subnets
            if len(n.config.Ipv6Subnets) > 0 {
                s := n.getSubnetforIPv6(ep.addrv6)
                if s == nil {
                    return fmt.Errorf("could not find a valid ipv6 subnet for endpoint %s", eid)
                }
                v6gw, _, err := net.ParseCIDR(s.GwIP)
                if err != nil {
                    return fmt.Errorf("gateway %s is not a valid ipv6 address: %v", s.GwIP, err)
                }
                err = jinfo.SetGatewayIPv6(v6gw)
                if err != nil {
                    return err
                }
                log.G(context.TODO()).Debugf("Ipvlan Endpoint Joined with IPv6_Addr: %s, Gateway: %s, Ipvlan_Mode: %s, Parent: %s",
                    ep.addrv6.IP.String(), v6gw.String(), n.config.IpvlanMode, n.config.Parent)
            }
        }
    } else {
        if len(n.config.Ipv4Subnets) > 0 {
            log.G(context.TODO()).Debugf("Ipvlan Endpoint Joined with IPv4_Addr: %s, IpVlan_Mode: %s, Parent: %s",
                ep.addr.IP.String(), n.config.IpvlanMode, n.config.Parent)
        }
        if len(n.config.Ipv6Subnets) > 0 {
            log.G(context.TODO()).Debugf("Ipvlan Endpoint Joined with IPv6_Addr: %s IpVlan_Mode: %s, Parent: %s",
                ep.addrv6.IP.String(), n.config.IpvlanMode, n.config.Parent)
        }
        // If n.config.Internal was set locally by the driver because there's no parent
        // interface, libnetwork doesn't know the network is internal. So, stop it from
        // adding a gateway endpoint.
        jinfo.DisableGatewayService()
    }
    iNames := jinfo.InterfaceName()
    err = iNames.SetNames(vethName, containerVethPrefix)
    if err != nil {
        return err
    }
    if err = d.storeUpdate(ep); err != nil {
        return fmt.Errorf("failed to save ipvlan endpoint %.7s to store: %v", ep.id, err)
    }

    return nil
}

// Leave method is invoked when a Sandbox detaches from an endpoint.
func (d *driver) Leave(nid, eid string) error {
    network, err := d.getNetwork(nid)
    if err != nil {
        return err
    }
    endpoint, err := network.getEndpoint(eid)
    if err != nil {
        return err
    }
    if endpoint == nil {
        return fmt.Errorf("could not find endpoint with id %s", eid)
    }

    return nil
}

// ifaceGateway returns a static route for either v4/v6 to be set to the container eth0
func ifaceGateway(dfNet string) (*staticRoute, error) {
    nh, dst, err := net.ParseCIDR(dfNet)
    if err != nil {
        return nil, fmt.Errorf("unable to parse default route %v", err)
    }
    defaultRoute := &staticRoute{
        Destination: dst,
        RouteType:   types.CONNECTED,
        NextHop:     nh,
    }

    return defaultRoute, nil
}

// getSubnetforIPv4 returns the ipv4 subnet to which the given IP belongs
func (n *network) getSubnetforIPv4(ip *net.IPNet) *ipSubnet {
    return getSubnetForIP(ip, n.config.Ipv4Subnets)
}

// getSubnetforIPv6 returns the ipv6 subnet to which the given IP belongs
func (n *network) getSubnetforIPv6(ip *net.IPNet) *ipSubnet {
    return getSubnetForIP(ip, n.config.Ipv6Subnets)
}

func getSubnetForIP(ip *net.IPNet, subnets []*ipSubnet) *ipSubnet {
    for _, s := range subnets {
        _, snet, err := net.ParseCIDR(s.SubnetIP)
        if err != nil {
            return nil
        }
        // first check if the mask lengths are the same
        i, _ := snet.Mask.Size()
        j, _ := ip.Mask.Size()
        if i != j {
            continue
        }
        if snet.Contains(ip.IP) {
            return s
        }
    }

    return nil
}