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route_linux.go
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route_linux.go
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package osl
import (
"fmt"
"net"
"github.com/docker/docker/libnetwork/types"
"github.com/vishvananda/netlink"
)
// Gateway returns the IPv4 gateway for the sandbox.
func (n *Namespace) Gateway() net.IP {
n.mu.Lock()
defer n.mu.Unlock()
return n.gw
}
// GatewayIPv6 returns the IPv6 gateway for the sandbox.
func (n *Namespace) GatewayIPv6() net.IP {
n.mu.Lock()
defer n.mu.Unlock()
return n.gwv6
}
// StaticRoutes returns additional static routes for the sandbox. Note that
// directly connected routes are stored on the particular interface they
// refer to.
func (n *Namespace) StaticRoutes() []*types.StaticRoute {
n.mu.Lock()
defer n.mu.Unlock()
routes := make([]*types.StaticRoute, len(n.staticRoutes))
for i, route := range n.staticRoutes {
r := route.GetCopy()
routes[i] = r
}
return routes
}
// SetGateway sets the default IPv4 gateway for the sandbox. It is a no-op
// if the given gateway is empty.
func (n *Namespace) SetGateway(gw net.IP) error {
if len(gw) == 0 {
return nil
}
if err := n.programGateway(gw, true); err != nil {
return err
}
n.mu.Lock()
n.gw = gw
n.mu.Unlock()
return nil
}
// UnsetGateway the previously set default IPv4 gateway in the sandbox.
// It is a no-op if no gateway was set.
func (n *Namespace) UnsetGateway() error {
gw := n.Gateway()
if len(gw) == 0 {
return nil
}
if err := n.programGateway(gw, false); err != nil {
return err
}
n.mu.Lock()
n.gw = net.IP{}
n.mu.Unlock()
return nil
}
func (n *Namespace) programGateway(gw net.IP, isAdd bool) error {
gwRoutes, err := n.nlHandle.RouteGet(gw)
if err != nil {
return fmt.Errorf("route for the gateway %s could not be found: %v", gw, err)
}
var linkIndex int
for _, gwRoute := range gwRoutes {
if gwRoute.Gw == nil {
linkIndex = gwRoute.LinkIndex
break
}
}
if linkIndex == 0 {
return fmt.Errorf("direct route for the gateway %s could not be found", gw)
}
if isAdd {
return n.nlHandle.RouteAdd(&netlink.Route{
Scope: netlink.SCOPE_UNIVERSE,
LinkIndex: linkIndex,
Gw: gw,
})
}
return n.nlHandle.RouteDel(&netlink.Route{
Scope: netlink.SCOPE_UNIVERSE,
LinkIndex: linkIndex,
Gw: gw,
})
}
// Program a route in to the namespace routing table.
func (n *Namespace) programRoute(dest *net.IPNet, nh net.IP) error {
gwRoutes, err := n.nlHandle.RouteGet(nh)
if err != nil {
return fmt.Errorf("route for the next hop %s could not be found: %v", nh, err)
}
return n.nlHandle.RouteAdd(&netlink.Route{
Scope: netlink.SCOPE_UNIVERSE,
LinkIndex: gwRoutes[0].LinkIndex,
Gw: nh,
Dst: dest,
})
}
// Delete a route from the namespace routing table.
func (n *Namespace) removeRoute(dest *net.IPNet, nh net.IP) error {
gwRoutes, err := n.nlHandle.RouteGet(nh)
if err != nil {
return fmt.Errorf("route for the next hop could not be found: %v", err)
}
return n.nlHandle.RouteDel(&netlink.Route{
Scope: netlink.SCOPE_UNIVERSE,
LinkIndex: gwRoutes[0].LinkIndex,
Gw: nh,
Dst: dest,
})
}
// SetGatewayIPv6 sets the default IPv6 gateway for the sandbox. It is a no-op
// if the given gateway is empty.
func (n *Namespace) SetGatewayIPv6(gwv6 net.IP) error {
if len(gwv6) == 0 {
return nil
}
if err := n.programGateway(gwv6, true); err != nil {
return err
}
n.mu.Lock()
n.gwv6 = gwv6
n.mu.Unlock()
return nil
}
// UnsetGatewayIPv6 unsets the previously set default IPv6 gateway in the sandbox.
// It is a no-op if no gateway was set.
func (n *Namespace) UnsetGatewayIPv6() error {
gwv6 := n.GatewayIPv6()
if len(gwv6) == 0 {
return nil
}
if err := n.programGateway(gwv6, false); err != nil {
return err
}
n.mu.Lock()
n.gwv6 = net.IP{}
n.mu.Unlock()
return nil
}
// AddStaticRoute adds a static route to the sandbox.
func (n *Namespace) AddStaticRoute(r *types.StaticRoute) error {
if err := n.programRoute(r.Destination, r.NextHop); err != nil {
return err
}
n.mu.Lock()
n.staticRoutes = append(n.staticRoutes, r)
n.mu.Unlock()
return nil
}
// RemoveStaticRoute removes a static route from the sandbox.
func (n *Namespace) RemoveStaticRoute(r *types.StaticRoute) error {
if err := n.removeRoute(r.Destination, r.NextHop); err != nil {
return err
}
n.mu.Lock()
lastIndex := len(n.staticRoutes) - 1
for i, v := range n.staticRoutes {
if v == r {
// Overwrite the route we're removing with the last element
n.staticRoutes[i] = n.staticRoutes[lastIndex]
// Shorten the slice to trim the extra element
n.staticRoutes = n.staticRoutes[:lastIndex]
break
}
}
n.mu.Unlock()
return nil
}