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package cluster
import (
"fmt"
"io/fs"
"net/netip"
"git.jpi.io/amery/jpictl/pkg/wireguard"
)
const (
// MaxZoneID indicates the highest ID allowed for a Zone
MaxZoneID = 0xf
// MaxNodeID indicates the highest Machine ID allowed within a Zone
MaxNodeID = 0xff - 1
// RingsCount indicates how many wireguard rings we have
RingsCount = 2
// RingZeroPort is the port wireguard uses for ring0
RingZeroPort = 51800
// RingOnePort is the port wireguard uses for ring1
RingOnePort = 51810
)
// RingInfo contains represents the Wireguard endpoint details
// for a Machine on a particular ring
type RingInfo struct {
Ring int
Enabled bool
Keys wireguard.KeyPair
}
// Merge attempts to combine two RingInfo structs
func (ri *RingInfo) Merge(alter *RingInfo) error {
switch {
case alter == nil:
return nil
case ri.Ring != alter.Ring:
// different ring
return fmt.Errorf("invalid %s: %v ≠ %v", "ring", ri.Ring, alter.Ring)
case ri.Enabled && !alter.Enabled:
// can't disable via Merge
return fmt.Errorf("invalid %s: %v → %v", "enabled", ri.Enabled, alter.Enabled)
case !canMergeKeyPairs(ri.Keys, alter.Keys):
// incompatible keypairs
return fmt.Errorf("invalid %s: %s ≠ %s", "keys", ri.Keys, alter.Keys)
}
return ri.unsafeMerge(alter)
}
func (ri *RingInfo) unsafeMerge(alter *RingInfo) error {
// enable via Merge
if alter.Enabled {
ri.Enabled = true
}
// fill the gaps on our keypair
if ri.Keys.PrivateKey.IsZero() {
ri.Keys.PrivateKey = alter.Keys.PrivateKey
}
if ri.Keys.PublicKey.IsZero() {
ri.Keys.PublicKey = alter.Keys.PublicKey
}
return nil
}
func canMergeKeyPairs(p1, p2 wireguard.KeyPair) bool {
switch {
case !p1.PrivateKey.IsZero() && !p2.PrivateKey.IsZero() && !p1.PrivateKey.Equal(p2.PrivateKey):
return false
case !p1.PublicKey.IsZero() && !p2.PublicKey.IsZero() && !p1.PublicKey.Equal(p2.PublicKey):
return false
default:
return true
}
}
// RingAddressEncoder provides encoder/decoder access for a particular
// Wireguard ring
type RingAddressEncoder struct {
ID int
Port uint16
Encode func(zoneID, nodeID int) (netip.Addr, bool)
Decode func(addr netip.Addr) (zoneID, nodeID int, ok bool)
}
var (
// RingZero is a wg0 address encoder/decoder
RingZero = RingAddressEncoder{
ID: 0,
Port: RingZeroPort,
Decode: ParseRingZeroAddress,
Encode: RingZeroAddress,
}
// RingOne is a wg1 address encoder/decoder
RingOne = RingAddressEncoder{
ID: 1,
Port: RingOnePort,
Decode: ParseRingOneAddress,
Encode: RingOneAddress,
}
// Rings provides indexed access to the ring address encoders
Rings = [RingsCount]RingAddressEncoder{
RingZero,
RingOne,
}
)
// ValidZoneID checks if the given zoneID is a valid 4 bit zone number.
//
// 0 is reserved, and only allowed when composing CIDRs.
func ValidZoneID(zoneID int) bool {
switch {
case zoneID < 0 || zoneID > MaxZoneID:
return false
default:
return true
}
}
// ValidNodeID checks if the given nodeID is a valid 8 bit number.
// nodeID is unique within a Zone.
// 0 is reserved, and only allowed when composing CIDRs.
func ValidNodeID(nodeID int) bool {
switch {
case nodeID < 0 || nodeID > MaxNodeID:
return false
default:
return true
}
}
// ParseRingZeroAddress extracts zone and node ID from a wg0 [netip.Addr]
// wg0 addresses are of the form `10.0.{{zoneID}}.{{nodeID}}`
func ParseRingZeroAddress(addr netip.Addr) (zoneID int, nodeID int, ok bool) {
if addr.IsValid() {
a4 := addr.As4()
if a4[0] == 10 && a4[1] == 0 {
return int(a4[2]), int(a4[3]), true
}
}
return 0, 0, false
}
// RingZeroAddress returns a wg0 IP address
func RingZeroAddress(zoneID, nodeID int) (netip.Addr, bool) {
switch {
case !ValidZoneID(zoneID) || !ValidNodeID(nodeID):
return netip.Addr{}, false
default:
a4 := [4]uint8{10, 0, uint8(zoneID), uint8(nodeID)}
return netip.AddrFrom4(a4), true
}
}
// ParseRingOneAddress extracts zone and node ID from a wg1 [netip.Addr]
// wg1 addresses are of the form `10.{{zoneID << 4}}.{{nodeID}}`
func ParseRingOneAddress(addr netip.Addr) (zoneID int, nodeID int, ok bool) {
if addr.IsValid() {
a4 := addr.As4()
if a4[0] == 10 && a4[2] == 0 {
zoneID = int(a4[1] >> 4)
nodeID = int(a4[3])
return zoneID, nodeID, true
}
}
return 0, 0, false
}
// RingOneAddress returns a wg1 IP address
func RingOneAddress(zoneID, nodeID int) (netip.Addr, bool) {
switch {
case !ValidZoneID(zoneID) || !ValidNodeID(nodeID):
return netip.Addr{}, false
default:
a4 := [4]uint8{10, uint8(zoneID << 4), 0, uint8(nodeID)}
return netip.AddrFrom4(a4), true
}
}
var (
_ MachineIterator = (*Ring)(nil)
_ ZoneIterator = (*Ring)(nil)
)
// A Ring describes all peers on a ring
type Ring struct {
RingAddressEncoder
ZoneIterator
Peers []*RingPeer
}
// AddPeer adds a [Machine] to the ring
func (r *Ring) AddPeer(p *Machine) bool {
ri, ok := p.getRingInfo(r.ID)
if !ok {
return false
}
nodeID := p.ID
zoneID := p.Zone()
addr, _ := r.Encode(zoneID, nodeID)
rp := &RingPeer{
Node: p,
Address: addr,
PrivateKey: ri.Keys.PrivateKey,
PeerConfig: wireguard.PeerConfig{
Name: fmt.Sprintf("%s-%v", p.Name, r.ID),
PublicKey: ri.Keys.PublicKey,
Endpoint: wireguard.EndpointAddress{
Host: p.FullName(),
Port: r.Port,
},
},
}
switch {
case r.ID == 0:
r.setRingZeroAllowedIPs(rp)
case p.IsGateway():
r.setRingOneGatewayAllowedIPs(rp)
default:
r.setRingOneNodeAllowedIPs(rp)
}
r.Peers = append(r.Peers, rp)
return true
}
func (r *Ring) setRingZeroAllowedIPs(rp *RingPeer) {
zoneID, _, _ := r.Decode(rp.Address)
// everyone on ring0 is a gateway to ring1
addr, _ := RingOneAddress(zoneID, 0)
rp.AllowCIDR(addr, 12)
// peer
rp.AllowCIDR(rp.Address, 32)
}
func (r *Ring) setRingOneGatewayAllowedIPs(rp *RingPeer) {
zoneID, _, _ := r.Decode(rp.Address)
// peer
rp.AllowCIDR(rp.Address, 32)
// ring1 gateways connect to all other ring1 networks
r.ForEachZone(func(z *Zone) bool {
if z.ID != zoneID {
addr, _ := r.Encode(z.ID, 0)
rp.AllowCIDR(addr, 12)
}
return false
})
// ring1 gateways also connect to all ring0 addresses
r.ForEachZone(func(z *Zone) bool {
z.ForEachMachine(func(p *Machine) bool {
if p.IsGateway() {
addr, _ := RingZeroAddress(z.ID, p.ID)
rp.AllowCIDR(addr, 32)
}
return false
})
return false
})
}
func (*Ring) setRingOneNodeAllowedIPs(rp *RingPeer) {
// only to the peer itself
rp.AllowCIDR(rp.Address, 32)
}
// ForEachMachine calls a function for each Machine in the ring
// until instructed to terminate the loop
func (r *Ring) ForEachMachine(fn func(*Machine) bool) {
for _, pp := range r.Peers {
if fn(pp.Node) {
return
}
}
}
// ExportConfig builds a wgN.conf for the specified machine on the ring
func (r *Ring) ExportConfig(p *Machine) (*wireguard.Config, error) {
var found bool
out := &wireguard.Config{
Interface: wireguard.InterfaceConfig{
ListenPort: r.Port,
},
}
for _, pp := range r.Peers {
switch {
case pp.Node == p:
// current
found = true
out.Interface.Name = pp.PeerConfig.Name
out.Interface.Address = pp.Address
out.Interface.PrivateKey = pp.PrivateKey
default:
// peer
pc := pp.PeerConfig
out.Peer = append(out.Peer, pc)
}
}
if !found {
return nil, fs.ErrNotExist
}
return out, nil
}
// A RingPeer is a node on a [Ring]
type RingPeer struct {
Node *Machine
Address netip.Addr
PrivateKey wireguard.PrivateKey
PeerConfig wireguard.PeerConfig
}
// AllowCIDR allows an IP range via this peer
func (rp *RingPeer) AllowCIDR(addr netip.Addr, bits int) {
cidr := netip.PrefixFrom(addr, bits)
rp.PeerConfig.AllowedIPs = append(rp.PeerConfig.AllowedIPs, cidr)
}
// NewRing composes a new Ring for Wireguard setup
func NewRing(z ZoneIterator, m MachineIterator, ring int) (*Ring, error) {
r := &Ring{
RingAddressEncoder: Rings[ring],
ZoneIterator: z,
}
m.ForEachMachine(func(p *Machine) bool {
r.AddPeer(p)
return false
})
return r, nil
}