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loader.go
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loader.go
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// Copyright 2018-2019 Authors of Cilium
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package loader
import (
"context"
"fmt"
"net"
"os"
"path"
"reflect"
"sync"
"github.com/cilium/cilium/pkg/bpf"
"github.com/cilium/cilium/pkg/byteorder"
"github.com/cilium/cilium/pkg/datapath"
"github.com/cilium/cilium/pkg/datapath/link"
"github.com/cilium/cilium/pkg/datapath/linux/route"
"github.com/cilium/cilium/pkg/datapath/loader/metrics"
datapathOption "github.com/cilium/cilium/pkg/datapath/option"
"github.com/cilium/cilium/pkg/defaults"
"github.com/cilium/cilium/pkg/elf"
"github.com/cilium/cilium/pkg/logging"
"github.com/cilium/cilium/pkg/logging/logfields"
"github.com/cilium/cilium/pkg/maps/callsmap"
"github.com/cilium/cilium/pkg/node"
"github.com/cilium/cilium/pkg/option"
"github.com/sirupsen/logrus"
"github.com/vishvananda/netlink"
)
const (
Subsystem = "datapath-loader"
symbolFromEndpoint = "from-container"
symbolToEndpoint = "to-container"
symbolFromHostNetdevEp = "from-netdev"
symbolToHostNetdevEp = "to-netdev"
symbolFromHostEp = "from-host"
symbolToHostEp = "to-host"
dirIngress = "ingress"
dirEgress = "egress"
)
var log = logging.DefaultLogger.WithField(logfields.LogSubsys, Subsystem)
// Loader is a wrapper structure around operations related to compiling,
// loading, and reloading datapath programs.
type Loader struct {
once sync.Once
// templateCache is the cache of pre-compiled datapaths.
templateCache *objectCache
canDisableDwarfRelocations bool
}
// NewLoader returns a new loader.
func NewLoader(canDisableDwarfRelocations bool) *Loader {
return &Loader{
canDisableDwarfRelocations: canDisableDwarfRelocations,
}
}
// Init initializes the datapath cache with base program hashes derived from
// the LocalNodeConfiguration.
func (l *Loader) init(dp datapath.ConfigWriter, nodeCfg *datapath.LocalNodeConfiguration) {
l.once.Do(func() {
l.templateCache = NewObjectCache(dp, nodeCfg)
ignorePrefixes := ignoredELFPrefixes
if !option.Config.EnableIPv4 {
ignorePrefixes = append(ignorePrefixes, "LXC_IPV4")
}
elf.IgnoreSymbolPrefixes(ignorePrefixes)
})
l.templateCache.Update(nodeCfg)
}
func upsertEndpointRoute(ep datapath.Endpoint, ip net.IPNet) error {
endpointRoute := route.Route{
Prefix: ip,
Device: ep.InterfaceName(),
Scope: netlink.SCOPE_LINK,
}
_, err := route.Upsert(endpointRoute)
return err
}
func removeEndpointRoute(ep datapath.Endpoint, ip net.IPNet) error {
return route.Delete(route.Route{
Prefix: ip,
Device: ep.InterfaceName(),
Scope: netlink.SCOPE_LINK,
})
}
// We need this function when patching an object file for which symbols were
// already substituted. During the first symbol substitutions, string symbols
// were replaced such that:
// template_string -> string_for_endpoint
// Since we only want to replace one int symbol, we can nullify string
// substitutions with:
// string_for_endpoint -> string_for_endpoint
// We cannot simply pass an empty map as the agent would complain that some
// symbol had no corresponding values.
func nullifyStringSubstitutions(strings map[string]string) map[string]string {
nullStrings := make(map[string]string)
for _, v := range strings {
nullStrings[v] = v
}
return nullStrings
}
// Since we attach the host endpoint datapath to two different interfaces, we
// need two different NODE_MAC values. patchHostNetdevDatapath creates a new
// object file for the native device, from the object file for the host device
// (cilium_host).
// Since the two object files should only differ by the values of their
// NODE_MAC symbols, we can avoid a full compilation.
func patchHostNetdevDatapath(ep datapath.Endpoint, objPath, dstPath, ifName string,
nodePortIPv4Addrs, nodePortIPv6Addrs map[string]net.IP) error {
hostObj, err := elf.Open(objPath)
if err != nil {
return err
}
defer hostObj.Close()
opts, strings := ELFSubstitutions(ep)
// The NODE_MAC value is specific to each attachment interface.
mac, err := link.GetHardwareAddr(ifName)
if err != nil {
return err
}
opts["NODE_MAC_1"] = sliceToBe32(mac[0:4])
opts["NODE_MAC_2"] = uint32(sliceToBe16(mac[4:6]))
ifIndex, err := link.GetIfIndex(ifName)
if err != nil {
return err
}
if option.Config.EnableNodePort && nodePortIPv4Addrs != nil && nodePortIPv6Addrs != nil {
opts["NATIVE_DEV_IFINDEX"] = ifIndex
if option.Config.EnableIPv4 {
ipv4 := nodePortIPv4Addrs[ifName]
opts["IPV4_NODEPORT"] = byteorder.HostSliceToNetwork(ipv4, reflect.Uint32).(uint32)
}
if option.Config.EnableIPv6 {
nodePortIPv6 := nodePortIPv6Addrs[ifName]
opts["IPV6_NODEPORT_1"] = sliceToBe32(nodePortIPv6[0:4])
opts["IPV6_NODEPORT_2"] = sliceToBe32(nodePortIPv6[4:8])
opts["IPV6_NODEPORT_3"] = sliceToBe32(nodePortIPv6[8:12])
opts["IPV6_NODEPORT_4"] = sliceToBe32(nodePortIPv6[12:16])
}
}
// Among string substitutions, only the calls map name is specific to each
// attachment interface.
strings = nullifyStringSubstitutions(strings)
callsMapHostDevice := bpf.LocalMapName(callsmap.HostMapName, uint16(ep.GetID()))
strings[callsMapHostDevice] = bpf.LocalMapName(callsmap.NetdevMapName, uint16(ifIndex))
return hostObj.Write(dstPath, opts, strings)
}
// reloadHostDatapath loads bpf_host programs attached to the host device
// (usually cilium_host) and the native devices if any. To that end, it
// uses a single object file, pointed to by objPath, compiled for the host
// device and patches it with values for native devices if needed.
// Symbols in objPath have already been substituted with the appropriate values
// for the host device. Thus, when packing the object file again for the native
// devices, we don't need to substitute most values (see
// nullifyStringSubstitutions above).
// reloadHostDatapath skips native devices that do not exist just before
// loading. If loading+attaching fails later on however, reloadHostDatapath
// will return with an error. Failing to load or to attach the host device
// always results in reloadHostDatapath returning with an error.
func (l *Loader) reloadHostDatapath(ctx context.Context, ep datapath.Endpoint, objPath string) error {
nbInterfaces := len(option.Config.Devices) + 2
symbols := make([]string, 2, nbInterfaces)
directions := make([]string, 2, nbInterfaces)
objPaths := make([]string, 2, nbInterfaces)
interfaceNames := make([]string, 2, nbInterfaces)
symbols[0], symbols[1] = symbolToHostEp, symbolFromHostEp
directions[0], directions[1] = dirIngress, dirEgress
objPaths[0], objPaths[1] = objPath, objPath
interfaceNames[0], interfaceNames[1] = ep.InterfaceName(), ep.InterfaceName()
if datapathHasMultipleMasterDevices() {
if _, err := netlink.LinkByName(defaults.SecondHostDevice); err != nil {
log.WithError(err).WithField("device", defaults.SecondHostDevice).Error("Link does not exist")
return err
} else {
interfaceNames = append(interfaceNames, defaults.SecondHostDevice)
symbols = append(symbols, symbolToHostEp)
directions = append(directions, dirIngress)
secondDevObjPath := path.Join(ep.StateDir(), hostEndpointPrefix+"_"+defaults.SecondHostDevice+".o")
if err := patchHostNetdevDatapath(ep, objPath, secondDevObjPath, defaults.SecondHostDevice, nil, nil); err != nil {
return err
}
objPaths = append(objPaths, secondDevObjPath)
}
}
nodePortIPv4Addrs := node.GetNodePortIPv4AddrsWithDevices()
nodePortIPv6Addrs := node.GetNodePortIPv6AddrsWithDevices()
for _, device := range option.Config.Devices {
if _, err := netlink.LinkByName(device); err != nil {
log.WithError(err).WithField("device", device).Warn("Link does not exist")
continue
}
netdevObjPath := path.Join(ep.StateDir(), hostEndpointNetdevPrefix+device+".o")
if err := patchHostNetdevDatapath(ep, objPath, netdevObjPath, device, nodePortIPv4Addrs, nodePortIPv6Addrs); err != nil {
return err
}
objPaths = append(objPaths, netdevObjPath)
interfaceNames = append(interfaceNames, device)
symbols = append(symbols, symbolFromHostNetdevEp)
directions = append(directions, dirIngress)
if option.Config.EnableNodePort || option.Config.EnableHostFirewall {
interfaceNames = append(interfaceNames, device)
symbols = append(symbols, symbolToHostNetdevEp)
directions = append(directions, dirEgress)
objPaths = append(objPaths, netdevObjPath)
} else {
// Remove any previously attached device from egress path if BPF
// NodePort and host firewall are disabled.
err := RemoveTCFilters(device, netlink.HANDLE_MIN_EGRESS)
if err != nil {
log.WithField("device", device).Error(err)
}
}
}
for i, interfaceName := range interfaceNames {
symbol := symbols[i]
if err := l.replaceDatapath(ctx, interfaceName, objPaths[i], symbol, directions[i]); err != nil {
scopedLog := ep.Logger(Subsystem).WithFields(logrus.Fields{
logfields.Path: objPath,
logfields.Veth: interfaceName,
})
// Don't log an error here if the context was canceled or timed out;
// this log message should only represent failures with respect to
// loading the program.
if ctx.Err() == nil {
scopedLog.WithError(err).Warningf("JoinEP: Failed to load program for host endpoint (%s)", symbol)
}
return err
}
}
return nil
}
func datapathHasMultipleMasterDevices() bool {
// In Flannel's case or when using ipvlan, HOST_DEV2 is equal to HOST_DEV1
// in init.sh and we have a single master device.
return option.Config.DatapathMode != datapathOption.DatapathModeIpvlan &&
!option.Config.IsFlannelMasterDeviceSet()
}
func (l *Loader) reloadDatapath(ctx context.Context, ep datapath.Endpoint, dirs *directoryInfo) error {
// Replace the current program
objPath := path.Join(dirs.Output, endpointObj)
if ep.IsHost() {
objPath = path.Join(dirs.Output, hostEndpointObj)
if err := l.reloadHostDatapath(ctx, ep, objPath); err != nil {
return err
}
} else if ep.HasIpvlanDataPath() {
if err := graftDatapath(ctx, ep.MapPath(), objPath, symbolFromEndpoint); err != nil {
scopedLog := ep.Logger(Subsystem).WithFields(logrus.Fields{
logfields.Path: objPath,
})
// Don't log an error here if the context was canceled or timed out;
// this log message should only represent failures with respect to
// loading the program.
if ctx.Err() == nil {
scopedLog.WithError(err).Warn("JoinEP: Failed to load program")
}
return err
}
} else {
if err := l.replaceDatapath(ctx, ep.InterfaceName(), objPath, symbolFromEndpoint, dirIngress); err != nil {
scopedLog := ep.Logger(Subsystem).WithFields(logrus.Fields{
logfields.Path: objPath,
logfields.Veth: ep.InterfaceName(),
})
// Don't log an error here if the context was canceled or timed out;
// this log message should only represent failures with respect to
// loading the program.
if ctx.Err() == nil {
scopedLog.WithError(err).Warn("JoinEP: Failed to load program")
}
return err
}
if ep.RequireEgressProg() {
if err := l.replaceDatapath(ctx, ep.InterfaceName(), objPath, symbolToEndpoint, dirEgress); err != nil {
scopedLog := ep.Logger(Subsystem).WithFields(logrus.Fields{
logfields.Path: objPath,
logfields.Veth: ep.InterfaceName(),
})
// Don't log an error here if the context was canceled or timed out;
// this log message should only represent failures with respect to
// loading the program.
if ctx.Err() == nil {
scopedLog.WithError(err).Warn("JoinEP: Failed to load program")
}
return err
}
}
}
if ep.RequireEndpointRoute() {
if ip := ep.IPv4Address(); ip.IsSet() {
upsertEndpointRoute(ep, *ip.IPNet(32))
}
if ip := ep.IPv6Address(); ip.IsSet() {
upsertEndpointRoute(ep, *ip.IPNet(128))
}
}
return nil
}
func (l *Loader) compileAndLoad(ctx context.Context, ep datapath.Endpoint, dirs *directoryInfo, stats *metrics.SpanStat) error {
debug := option.Config.BPFCompilationDebug
stats.BpfCompilation.Start()
err := compileDatapath(ctx, dirs, ep.IsHost(), debug, ep.Logger(Subsystem))
stats.BpfCompilation.End(err == nil)
if err != nil {
return err
}
stats.BpfLoadProg.Start()
err = l.reloadDatapath(ctx, ep, dirs)
stats.BpfLoadProg.End(err == nil)
return err
}
// CompileAndLoad compiles the BPF datapath programs for the specified endpoint
// and loads it onto the interface associated with the endpoint.
//
// Expects the caller to have created the directory at the path ep.StateDir().
func (l *Loader) CompileAndLoad(ctx context.Context, ep datapath.Endpoint, stats *metrics.SpanStat) error {
if ep == nil {
log.Fatalf("LoadBPF() doesn't support non-endpoint load")
}
dirs := directoryInfo{
Library: option.Config.BpfDir,
Runtime: option.Config.StateDir,
State: ep.StateDir(),
Output: ep.StateDir(),
}
return l.compileAndLoad(ctx, ep, &dirs, stats)
}
// CompileOrLoad loads the BPF datapath programs for the specified endpoint.
//
// In contrast with CompileAndLoad(), it attempts to find a pre-compiled
// template datapath object to use, to avoid a costly compile operation.
// Only if there is no existing template that has the same configuration
// parameters as the specified endpoint, this function will compile a new
// template for this configuration.
//
// This function will block if the cache does not contain an entry for the
// same EndpointConfiguration and multiple goroutines attempt to concurrently
// CompileOrLoad with the same configuration parameters. When the first
// goroutine completes compilation of the template, all other CompileOrLoad
// invocations will be released.
func (l *Loader) CompileOrLoad(ctx context.Context, ep datapath.Endpoint, stats *metrics.SpanStat) error {
templatePath, _, err := l.templateCache.fetchOrCompile(ctx, ep, stats)
if err != nil {
return err
}
template, err := elf.Open(templatePath)
if err != nil {
return err
}
defer template.Close()
symPath := path.Join(ep.StateDir(), defaults.TemplatePath)
if _, err := os.Stat(symPath); err == nil {
if err = os.RemoveAll(symPath); err != nil {
return &os.PathError{
Op: "Failed to remove old symlink",
Path: symPath,
Err: err,
}
}
} else if !os.IsNotExist(err) {
return &os.PathError{
Op: "Failed to locate symlink",
Path: symPath,
Err: err,
}
}
if err := os.Symlink(templatePath, symPath); err != nil {
return &os.PathError{
Op: fmt.Sprintf("Failed to create symlink to %s", templatePath),
Path: symPath,
Err: err,
}
}
stats.BpfWriteELF.Start()
epObj := endpointObj
if ep.IsHost() {
epObj = hostEndpointObj
}
dstPath := path.Join(ep.StateDir(), epObj)
opts, strings := ELFSubstitutions(ep)
if err = template.Write(dstPath, opts, strings); err != nil {
stats.BpfWriteELF.End(err == nil)
return err
}
stats.BpfWriteELF.End(err == nil)
return l.ReloadDatapath(ctx, ep, stats)
}
// ReloadDatapath reloads the BPF datapath pgorams for the specified endpoint.
func (l *Loader) ReloadDatapath(ctx context.Context, ep datapath.Endpoint, stats *metrics.SpanStat) (err error) {
dirs := directoryInfo{
Library: option.Config.BpfDir,
Runtime: option.Config.StateDir,
State: ep.StateDir(),
Output: ep.StateDir(),
}
stats.BpfLoadProg.Start()
err = l.reloadDatapath(ctx, ep, &dirs)
stats.BpfLoadProg.End(err == nil)
return err
}
// Unload removes the datapath specific program aspects
func (l *Loader) Unload(ep datapath.Endpoint) {
if ep.RequireEndpointRoute() {
if ip := ep.IPv4Address(); ip.IsSet() {
removeEndpointRoute(ep, *ip.IPNet(32))
}
if ip := ep.IPv6Address(); ip.IsSet() {
removeEndpointRoute(ep, *ip.IPNet(128))
}
}
}
// EndpointHash hashes the specified endpoint configuration with the current
// datapath hash cache and returns the hash as string.
func (l *Loader) EndpointHash(cfg datapath.EndpointConfiguration) (string, error) {
return l.templateCache.baseHash.sumEndpoint(l.templateCache, cfg, true)
}
// CallsMapPath gets the BPF Calls Map for the endpoint with the specified ID.
func (l *Loader) CallsMapPath(id uint16) string {
return bpf.LocalMapPath(callsmap.MapName, id)
}