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forked from extern/smegmesh
smegmesh/pkg/mesh/config.go

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package mesh
import (
"fmt"
"net"
"slices"
"strings"
"time"
"github.com/tim-beatham/wgmesh/pkg/conf"
"github.com/tim-beatham/wgmesh/pkg/ip"
"github.com/tim-beatham/wgmesh/pkg/lib"
"github.com/tim-beatham/wgmesh/pkg/route"
"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
)
// MeshConfigApplyer abstracts applying the mesh configuration
type MeshConfigApplyer interface {
ApplyConfig() error
RemovePeers(meshId string) error
SetMeshManager(manager MeshManager)
}
// WgMeshConfigApplyer applies WireGuard configuration
type WgMeshConfigApplyer struct {
meshManager MeshManager
routeInstaller route.RouteInstaller
hashFunc func(MeshNode) int
}
type routeNode struct {
gateway string
route Route
}
type convertMeshNodeParams struct {
node MeshNode
self MeshNode
mesh MeshProvider
device *wgtypes.Device
peerToClients map[string][]net.IPNet
routes map[string][]routeNode
}
func (m *WgMeshConfigApplyer) convertMeshNode(params convertMeshNodeParams) (*wgtypes.PeerConfig, error) {
pubKey, err := params.node.GetPublicKey()
if err != nil {
return nil, err
}
allowedips := make([]net.IPNet, 1)
allowedips[0] = *params.node.GetWgHost()
clients, ok := params.peerToClients[pubKey.String()]
if ok {
allowedips = append(allowedips, clients...)
}
for _, route := range params.node.GetRoutes() {
bestRoutes := params.routes[route.GetDestination().String()]
var pickedRoute routeNode
if len(bestRoutes) == 1 {
pickedRoute = bestRoutes[0]
} else if len(bestRoutes) > 1 {
bucketFunc := func(rn routeNode) int {
return lib.HashString(rn.gateway)
}
// Else there is more than one candidate so consistently hash
pickedRoute = lib.ConsistentHash(bestRoutes, params.self, bucketFunc, m.hashFunc)
}
if pickedRoute.gateway == pubKey.String() {
allowedips = append(allowedips, *pickedRoute.route.GetDestination())
}
}
config := params.mesh.GetConfiguration()
var keepAlive time.Duration = time.Duration(0)
if config.KeepAliveWg != nil {
keepAlive = time.Duration(*config.KeepAliveWg) * time.Second
}
existing := slices.IndexFunc(params.device.Peers, func(p wgtypes.Peer) bool {
pubKey, _ := params.node.GetPublicKey()
return p.PublicKey.String() == pubKey.String()
})
var endpoint *net.UDPAddr = nil
if params.node.GetType() == conf.PEER_ROLE {
endpoint, err = net.ResolveUDPAddr("udp", params.node.GetWgEndpoint())
}
if err != nil {
return nil, err
}
// Don't override the existing IP in case it already exists
if existing != -1 {
endpoint = params.device.Peers[existing].Endpoint
}
peerConfig := wgtypes.PeerConfig{
PublicKey: pubKey,
Endpoint: endpoint,
AllowedIPs: allowedips,
PersistentKeepaliveInterval: &keepAlive,
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ReplaceAllowedIPs: true,
}
return &peerConfig, nil
}
// getRoutes: finds the routes with the least hop distance. If more than one route exists
// consistently hash to evenly spread the distribution of traffic
func (m *WgMeshConfigApplyer) getRoutes(meshProvider MeshProvider) (map[string][]routeNode, error) {
mesh, _ := meshProvider.GetMesh()
routes := make(map[string][]routeNode)
peers := lib.Filter(lib.MapValues(mesh.GetNodes()), func(p MeshNode) bool {
return p.GetType() == conf.PEER_ROLE
})
meshPrefixes := lib.Map(lib.MapValues(m.meshManager.GetMeshes()), func(mesh MeshProvider) *net.IPNet {
ula := &ip.ULABuilder{}
ipNet, _ := ula.GetIPNet(mesh.GetMeshId())
return ipNet
})
for _, node := range mesh.GetNodes() {
pubKey, _ := node.GetPublicKey()
for _, route := range node.GetRoutes() {
if lib.Contains(meshPrefixes, func(prefix *net.IPNet) bool {
if prefix.IP.Equal(net.IPv6zero) && *meshProvider.GetConfiguration().AdvertiseDefaultRoute {
return true
}
return prefix.Contains(route.GetDestination().IP)
}) {
continue
}
destination := route.GetDestination().String()
otherRoute, ok := routes[destination]
rn := routeNode{
gateway: pubKey.String(),
route: route,
}
// Client's only acessible by another peer
if node.GetType() == conf.CLIENT_ROLE {
peer := m.getCorrespondingPeer(peers, node)
self, err := meshProvider.GetNode(m.meshManager.GetPublicKey().String())
if err != nil {
return nil, err
}
if !NodeEquals(peer, self) {
peerPub, _ := peer.GetPublicKey()
rn.gateway = peerPub.String()
rn.route = &RouteStub{
Destination: rn.route.GetDestination(),
HopCount: rn.route.GetHopCount() + 1,
Path: append(rn.route.GetPath(), peer.GetWgHost().IP.String()),
}
}
}
if !ok {
otherRoute = make([]routeNode, 1)
otherRoute[0] = rn
routes[destination] = otherRoute
} else if route.GetHopCount() < otherRoute[0].route.GetHopCount() {
otherRoute[0] = rn
} else if otherRoute[0].route.GetHopCount() == route.GetHopCount() {
routes[destination] = append(otherRoute, rn)
}
}
}
return routes, nil
}
// getCorrespondignPeer: gets the peer corresponding to the client
func (m *WgMeshConfigApplyer) getCorrespondingPeer(peers []MeshNode, client MeshNode) MeshNode {
peer := lib.ConsistentHash(peers, client, m.hashFunc, m.hashFunc)
return peer
}
func (m *WgMeshConfigApplyer) getPeerCfgsToRemove(dev *wgtypes.Device, newPeers []wgtypes.PeerConfig) []wgtypes.PeerConfig {
peers := dev.Peers
peers = lib.Filter(peers, func(p1 wgtypes.Peer) bool {
return !lib.Contains(newPeers, func(p2 wgtypes.PeerConfig) bool {
return p1.PublicKey.String() == p2.PublicKey.String()
})
})
return lib.Map(peers, func(p wgtypes.Peer) wgtypes.PeerConfig {
return wgtypes.PeerConfig{
PublicKey: p.PublicKey,
Remove: true,
}
})
}
type GetConfigParams struct {
mesh MeshProvider
peers []MeshNode
clients []MeshNode
dev *wgtypes.Device
routes map[string][]routeNode
}
func (m *WgMeshConfigApplyer) getClientConfig(params *GetConfigParams) (*wgtypes.Config, error) {
ula := &ip.ULABuilder{}
meshNet, _ := ula.GetIPNet(params.mesh.GetMeshId())
routesForMesh := lib.Map(lib.MapValues(params.routes), func(rns []routeNode) []routeNode {
return lib.Filter(rns, func(rn routeNode) bool {
ip, _, _ := net.ParseCIDR(rn.gateway)
return meshNet.Contains(ip)
})
})
routes := lib.Map(routesForMesh, func(rs []routeNode) net.IPNet {
return *rs[0].route.GetDestination()
})
routes = append(routes, *meshNet)
self, err := params.mesh.GetNode(m.meshManager.GetPublicKey().String())
if err != nil {
return nil, err
}
peer := m.getCorrespondingPeer(params.peers, self)
pubKey, _ := peer.GetPublicKey()
config := params.mesh.GetConfiguration()
keepAlive := time.Duration(*config.KeepAliveWg) * time.Second
endpoint, err := net.ResolveUDPAddr("udp", peer.GetWgEndpoint())
if err != nil {
return nil, err
}
peerCfgs := make([]wgtypes.PeerConfig, 1)
peerCfgs[0] = wgtypes.PeerConfig{
PublicKey: pubKey,
Endpoint: endpoint,
PersistentKeepaliveInterval: &keepAlive,
AllowedIPs: routes,
ReplaceAllowedIPs: true,
}
installedRoutes := make([]lib.Route, 0)
for _, route := range peerCfgs[0].AllowedIPs {
installedRoutes = append(installedRoutes, lib.Route{
Gateway: peer.GetWgHost().IP,
Destination: route,
})
}
cfg := wgtypes.Config{
Peers: peerCfgs,
}
m.routeInstaller.InstallRoutes(params.dev.Name, installedRoutes...)
return &cfg, err
}
func (m *WgMeshConfigApplyer) getRoutesToInstall(wgNode *wgtypes.PeerConfig, mesh MeshProvider, node MeshNode) []lib.Route {
routes := make([]lib.Route, 0)
for _, route := range wgNode.AllowedIPs {
ula := &ip.ULABuilder{}
ipNet, _ := ula.GetIPNet(mesh.GetMeshId())
_, defaultRoute, _ := net.ParseCIDR("::/0")
if !ipNet.Contains(route.IP) && !ipNet.IP.Equal(defaultRoute.IP) {
routes = append(routes, lib.Route{
Gateway: node.GetWgHost().IP,
Destination: route,
})
}
}
return routes
}
func (m *WgMeshConfigApplyer) getPeerConfig(params *GetConfigParams) (*wgtypes.Config, error) {
peerToClients := make(map[string][]net.IPNet)
installedRoutes := make([]lib.Route, 0)
peerConfigs := make([]wgtypes.PeerConfig, 0)
self, err := params.mesh.GetNode(m.meshManager.GetPublicKey().String())
if err != nil {
return nil, err
}
for _, n := range params.clients {
if len(params.peers) > 0 {
peer := m.getCorrespondingPeer(params.peers, n)
pubKey, _ := peer.GetPublicKey()
clients, ok := peerToClients[pubKey.String()]
if !ok {
clients = make([]net.IPNet, 0)
peerToClients[pubKey.String()] = clients
}
peerToClients[pubKey.String()] = append(clients, *n.GetWgHost())
if NodeEquals(self, peer) {
cfg, err := m.convertMeshNode(convertMeshNodeParams{
node: n,
self: self,
mesh: params.mesh,
device: params.dev,
peerToClients: peerToClients,
routes: params.routes,
})
if err != nil {
return nil, err
}
installedRoutes = append(installedRoutes, m.getRoutesToInstall(cfg, params.mesh, n)...)
peerConfigs = append(peerConfigs, *cfg)
}
}
}
for _, n := range params.peers {
if NodeEquals(n, self) {
continue
}
peer, err := m.convertMeshNode(convertMeshNodeParams{
node: n,
self: self,
mesh: params.mesh,
peerToClients: peerToClients,
routes: params.routes,
device: params.dev,
})
if err != nil {
return nil, err
}
installedRoutes = append(installedRoutes, m.getRoutesToInstall(peer, params.mesh, n)...)
peerConfigs = append(peerConfigs, *peer)
}
cfg := wgtypes.Config{
Peers: peerConfigs,
}
err = m.routeInstaller.InstallRoutes(params.dev.Name, installedRoutes...)
return &cfg, err
}
func (m *WgMeshConfigApplyer) updateWgConf(mesh MeshProvider, routes map[string][]routeNode) error {
snap, err := mesh.GetMesh()
if err != nil {
return err
}
nodes := lib.MapValues(snap.GetNodes())
dev, _ := mesh.GetDevice()
slices.SortFunc(nodes, func(a, b MeshNode) int {
return strings.Compare(string(a.GetType()), string(b.GetType()))
})
peers := lib.Filter(nodes, func(mn MeshNode) bool {
return mn.GetType() == conf.PEER_ROLE
})
clients := lib.Filter(nodes, func(mn MeshNode) bool {
return mn.GetType() == conf.CLIENT_ROLE
})
self, err := mesh.GetNode(m.meshManager.GetPublicKey().String())
if err != nil {
return err
}
var cfg *wgtypes.Config = nil
configParams := &GetConfigParams{
mesh: mesh,
peers: peers,
clients: clients,
dev: dev,
routes: routes,
}
switch self.GetType() {
case conf.PEER_ROLE:
cfg, err = m.getPeerConfig(configParams)
case conf.CLIENT_ROLE:
cfg, err = m.getClientConfig(configParams)
}
if err != nil {
return err
}
toRemove := m.getPeerCfgsToRemove(dev, cfg.Peers)
cfg.Peers = append(cfg.Peers, toRemove...)
err = m.meshManager.GetClient().ConfigureDevice(dev.Name, *cfg)
if err != nil {
return err
}
return nil
}
func (m *WgMeshConfigApplyer) getAllRoutes() (map[string][]routeNode, error) {
allRoutes := make(map[string][]routeNode)
for _, mesh := range m.meshManager.GetMeshes() {
routes, err := m.getRoutes(mesh)
if err != nil {
return nil, err
}
for destination, route := range routes {
_, ok := allRoutes[destination]
if !ok {
allRoutes[destination] = route
continue
}
if allRoutes[destination][0].route.GetHopCount() == route[0].route.GetHopCount() {
allRoutes[destination] = append(allRoutes[destination], route...)
} else if route[0].route.GetHopCount() < allRoutes[destination][0].route.GetHopCount() {
allRoutes[destination] = route
}
}
}
return allRoutes, nil
}
func (m *WgMeshConfigApplyer) ApplyConfig() error {
allRoutes, err := m.getAllRoutes()
if err != nil {
return err
}
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for _, mesh := range m.meshManager.GetMeshes() {
err := m.updateWgConf(mesh, allRoutes)
if err != nil {
return err
}
}
return nil
}
func (m *WgMeshConfigApplyer) RemovePeers(meshId string) error {
mesh := m.meshManager.GetMesh(meshId)
if mesh == nil {
return fmt.Errorf("mesh %s does not exist", meshId)
}
dev, err := mesh.GetDevice()
if err != nil {
return err
}
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m.meshManager.GetClient().ConfigureDevice(dev.Name, wgtypes.Config{
Peers: make([]wgtypes.PeerConfig, 0),
ReplacePeers: true,
})
return nil
}
func (m *WgMeshConfigApplyer) SetMeshManager(manager MeshManager) {
m.meshManager = manager
}
func NewWgMeshConfigApplyer() MeshConfigApplyer {
return &WgMeshConfigApplyer{
routeInstaller: route.NewRouteInstaller(),
hashFunc: func(mn MeshNode) int {
pubKey, _ := mn.GetPublicKey()
return lib.HashString(pubKey.String())
},
}
}