tailscale/wgengine/wgcfg/nmcfg/nmcfg.go
Brad Fitzpatrick 4e0fc037e6 all: use iterators over slice views more
This gets close to all of the remaining ones.

Updates #12912

Change-Id: I9c672bbed2654a6c5cab31e0cbece6c107d8c6fa
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2024-11-11 13:22:34 -08:00

149 lines
4.4 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package nmcfg converts a controlclient.NetMap into a wgcfg config.
package nmcfg
import (
"bytes"
"fmt"
"net/netip"
"strings"
"tailscale.com/tailcfg"
"tailscale.com/types/logger"
"tailscale.com/types/logid"
"tailscale.com/types/netmap"
"tailscale.com/wgengine/wgcfg"
)
func nodeDebugName(n tailcfg.NodeView) string {
name := n.Name()
if name == "" {
name = n.Hostinfo().Hostname()
}
if i := strings.Index(name, "."); i != -1 {
name = name[:i]
}
if name == "" && n.Addresses().Len() != 0 {
return n.Addresses().At(0).String()
}
return name
}
// cidrIsSubnet reports whether cidr is a non-default-route subnet
// exported by node that is not one of its own self addresses.
func cidrIsSubnet(node tailcfg.NodeView, cidr netip.Prefix) bool {
if cidr.Bits() == 0 {
return false
}
if !cidr.IsSingleIP() {
return true
}
for _, selfCIDR := range node.Addresses().All() {
if cidr == selfCIDR {
return false
}
}
return true
}
// WGCfg returns the NetworkMaps's WireGuard configuration.
func WGCfg(nm *netmap.NetworkMap, logf logger.Logf, flags netmap.WGConfigFlags, exitNode tailcfg.StableNodeID) (*wgcfg.Config, error) {
cfg := &wgcfg.Config{
Name: "tailscale",
PrivateKey: nm.PrivateKey,
Addresses: nm.GetAddresses().AsSlice(),
Peers: make([]wgcfg.Peer, 0, len(nm.Peers)),
}
// Setup log IDs for data plane audit logging.
if nm.SelfNode.Valid() {
cfg.NodeID = nm.SelfNode.StableID()
canNetworkLog := nm.SelfNode.HasCap(tailcfg.CapabilityDataPlaneAuditLogs)
logExitFlowEnabled := nm.SelfNode.HasCap(tailcfg.NodeAttrLogExitFlows)
if canNetworkLog && nm.SelfNode.DataPlaneAuditLogID() != "" && nm.DomainAuditLogID != "" {
nodeID, errNode := logid.ParsePrivateID(nm.SelfNode.DataPlaneAuditLogID())
if errNode != nil {
logf("[v1] wgcfg: unable to parse node audit log ID: %v", errNode)
}
domainID, errDomain := logid.ParsePrivateID(nm.DomainAuditLogID)
if errDomain != nil {
logf("[v1] wgcfg: unable to parse domain audit log ID: %v", errDomain)
}
if errNode == nil && errDomain == nil {
cfg.NetworkLogging.NodeID = nodeID
cfg.NetworkLogging.DomainID = domainID
cfg.NetworkLogging.LogExitFlowEnabled = logExitFlowEnabled
}
}
}
// Logging buffers
skippedUnselected := new(bytes.Buffer)
skippedIPs := new(bytes.Buffer)
skippedSubnets := new(bytes.Buffer)
for _, peer := range nm.Peers {
if peer.DiscoKey().IsZero() && peer.DERP() == "" && !peer.IsWireGuardOnly() {
// Peer predates both DERP and active discovery, we cannot
// communicate with it.
logf("[v1] wgcfg: skipped peer %s, doesn't offer DERP or disco", peer.Key().ShortString())
continue
}
// Skip expired peers; we'll end up failing to connect to them
// anyway, since control intentionally breaks node keys for
// expired peers so that we can't discover endpoints via DERP.
if peer.Expired() {
logf("[v1] wgcfg: skipped expired peer %s", peer.Key().ShortString())
continue
}
cfg.Peers = append(cfg.Peers, wgcfg.Peer{
PublicKey: peer.Key(),
DiscoKey: peer.DiscoKey(),
})
cpeer := &cfg.Peers[len(cfg.Peers)-1]
didExitNodeWarn := false
cpeer.V4MasqAddr = peer.SelfNodeV4MasqAddrForThisPeer()
cpeer.V6MasqAddr = peer.SelfNodeV6MasqAddrForThisPeer()
cpeer.IsJailed = peer.IsJailed()
for _, allowedIP := range peer.AllowedIPs().All() {
if allowedIP.Bits() == 0 && peer.StableID() != exitNode {
if didExitNodeWarn {
// Don't log about both the IPv4 /0 and IPv6 /0.
continue
}
didExitNodeWarn = true
if skippedUnselected.Len() > 0 {
skippedUnselected.WriteString(", ")
}
fmt.Fprintf(skippedUnselected, "%q (%v)", nodeDebugName(peer), peer.Key().ShortString())
continue
} else if cidrIsSubnet(peer, allowedIP) {
if (flags & netmap.AllowSubnetRoutes) == 0 {
if skippedSubnets.Len() > 0 {
skippedSubnets.WriteString(", ")
}
fmt.Fprintf(skippedSubnets, "%v from %q (%v)", allowedIP, nodeDebugName(peer), peer.Key().ShortString())
continue
}
}
cpeer.AllowedIPs = append(cpeer.AllowedIPs, allowedIP)
}
}
if skippedUnselected.Len() > 0 {
logf("[v1] wgcfg: skipped unselected default routes from: %s", skippedUnselected.Bytes())
}
if skippedIPs.Len() > 0 {
logf("[v1] wgcfg: skipped node IPs: %s", skippedIPs)
}
if skippedSubnets.Len() > 0 {
logf("[v1] wgcfg: did not accept subnet routes: %s", skippedSubnets)
}
return cfg, nil
}