ab35df454d
Removed pre-go1.17 build-tags with go fix;
go mod init
go fix -mod=readonly ./...
rm go.mod
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
80 lines
2.3 KiB
Go
80 lines
2.3 KiB
Go
//go:build linux
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// Network utility functions.
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package netutils
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import (
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"net"
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"os"
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"github.com/docker/docker/libnetwork/ns"
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"github.com/docker/docker/libnetwork/resolvconf"
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"github.com/docker/docker/libnetwork/types"
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"github.com/pkg/errors"
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"github.com/vishvananda/netlink"
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)
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var networkGetRoutesFct func(netlink.Link, int) ([]netlink.Route, error)
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// CheckRouteOverlaps checks whether the passed network overlaps with any existing routes
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func CheckRouteOverlaps(toCheck *net.IPNet) error {
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networkGetRoutesFct := networkGetRoutesFct
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if networkGetRoutesFct == nil {
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networkGetRoutesFct = ns.NlHandle().RouteList
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}
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networks, err := networkGetRoutesFct(nil, netlink.FAMILY_V4)
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if err != nil {
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return err
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}
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for _, network := range networks {
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if network.Dst != nil && network.Scope == netlink.SCOPE_LINK && NetworkOverlaps(toCheck, network.Dst) {
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return ErrNetworkOverlaps
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}
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}
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return nil
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}
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// GenerateIfaceName returns an interface name using the passed in
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// prefix and the length of random bytes. The api ensures that the
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// there are is no interface which exists with that name.
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func GenerateIfaceName(nlh *netlink.Handle, prefix string, len int) (string, error) {
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linkByName := netlink.LinkByName
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if nlh != nil {
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linkByName = nlh.LinkByName
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}
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for i := 0; i < 3; i++ {
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name, err := GenerateRandomName(prefix, len)
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if err != nil {
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return "", err
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}
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_, err = linkByName(name)
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if err != nil {
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if errors.As(err, &netlink.LinkNotFoundError{}) {
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return name, nil
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}
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return "", err
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}
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}
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return "", types.InternalErrorf("could not generate interface name")
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}
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// FindAvailableNetwork returns a network from the passed list which does not
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// overlap with existing interfaces in the system
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func FindAvailableNetwork(list []*net.IPNet) (*net.IPNet, error) {
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// We don't check for an error here, because we don't really care if we
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// can't read /etc/resolv.conf. So instead we skip the append if resolvConf
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// is nil. It either doesn't exist, or we can't read it for some reason.
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var nameservers []string
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if rc, err := os.ReadFile(resolvconf.Path()); err == nil {
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nameservers = resolvconf.GetNameserversAsCIDR(rc)
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}
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for _, nw := range list {
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if err := CheckNameserverOverlaps(nameservers, nw); err == nil {
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if err := CheckRouteOverlaps(nw); err == nil {
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return nw, nil
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}
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}
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}
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return nil, errors.New("no available network")
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}
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