zones: introduce Wireguard Ring Config factory

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/wireguard/config.go

@@ -1,17 +1,40 @@
 package wireguard
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
 	"net/netip"
 	"strconv"
 	"strings"
+	"text/template"
 
 	"darvaza.org/core"
 	"gopkg.in/gcfg.v1"
 )
 
+var configTemplate = template.Must(template.New("config").Funcs(template.FuncMap{
+	"PrefixJoin": func(a []netip.Prefix, sep string) string {
+		s := make([]string, len(a))
+		for i, p := range a {
+			s[i] = p.String()
+		}
+		return strings.Join(s, sep)
+	},
+}).Parse(`[Interface]
+Address = {{.Interface.Address}}
+PrivateKey = {{.Interface.PrivateKey}}
+ListenPort = {{.Interface.ListenPort}}
+{{- range .Peer }}
+
+[Peer]
+PublicKey = {{.PublicKey}}
+Endpoint = {{.Endpoint}}
+AllowedIPs = {{ PrefixJoin .AllowedIPs ", "}}
+{{- end }}
+`))
+
 // Config represents a wgN.conf file
 type Config struct {
 	Interface InterfaceConfig
@@ -28,6 +51,17 @@ func (f *Config) Peers() int {
 	return len(f.Peer)
 }
 
+// WriteTo writes a Wireguard [Config] onto the provided [io.Writer]
+func (f *Config) WriteTo(w io.Writer) (int64, error) {
+	var buf bytes.Buffer
+
+	if err := configTemplate.Execute(&buf, f); err != nil {
+		return 0, err
+	}
+
+	return buf.WriteTo(w)
+}
+
 // InterfaceConfig represents the [Interface] section
 type InterfaceConfig struct {
 	Address    netip.Addr

pkg/zones/machine.go

@@ -43,6 +43,11 @@ func (m *Machine) IsGateway() bool {
 	return ok
 }
 
+// Zone indicates the [Zone] this machine belongs to
+func (m *Machine) Zone() int {
+	return m.zone.ID
+}
+
 func (m *Machine) getPeerByName(name string) (*Machine, bool) {
 	return m.zone.zones.GetMachineByName(name)
 }

pkg/zones/rings.go

@@ -2,6 +2,7 @@ package zones
 
 import (
 	"fmt"
+	"io/fs"
 	"net/netip"
 
 	"git.jpi.io/amery/jpictl/pkg/wireguard"
@@ -179,3 +180,168 @@ func RingOneAddress(zoneID, nodeID int) (netip.Addr, bool) {
 		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{
+			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.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
+}

pkg/zones/zone_rings.go

@@ -5,9 +5,29 @@ import "os"
 // PruneWireguardConfig removes wgN.conf files of machines with
 // the corresponding ring disabled.
 func (z *Zone) PruneWireguardConfig(ring int) error {
+	return pruneWireguardConfig(z, ring)
+}
+
+// WriteWireguardKeys rewrites all wgN.{key,pub} files on this zone
+func (z *Zone) WriteWireguardKeys(ring int) error {
+	return writeWireguardKeys(z, ring)
+}
+
+// PruneWireguardConfig removes wgN.conf files of machines with
+// the corresponding ring disabled on all zones
+func (m *Zones) PruneWireguardConfig(ring int) error {
+	return pruneWireguardConfig(m, ring)
+}
+
+// WriteWireguardKeys rewrites all wgN.{key,pub} files
+func (m *Zones) WriteWireguardKeys(ring int) error {
+	return writeWireguardKeys(m, ring)
+}
+
+func pruneWireguardConfig(m MachineIterator, ring int) error {
 	var err error
 
-	z.ForEachMachine(func(p *Machine) bool {
+	m.ForEachMachine(func(p *Machine) bool {
 		_, ok := p.getRingInfo(ring)
 		if !ok {
 			err = p.RemoveWireguardConfig(ring)
@@ -18,11 +38,10 @@ func (z *Zone) PruneWireguardConfig(ring int) error {
 	return err
 }
 
-// WriteWireguardKeys rewrites all wgN.{key,pub} files on this zone
+func writeWireguardKeys(m MachineIterator, ring int) error {
-func (z *Zone) WriteWireguardKeys(ring int) error {
 	var err error
 
-	z.ForEachMachine(func(p *Machine) bool {
+	m.ForEachMachine(func(p *Machine) bool {
 		err = p.WriteWireguardKeys(ring)
 		if os.IsNotExist(err) {
 			// ignore
@@ -34,28 +53,3 @@ func (z *Zone) WriteWireguardKeys(ring int) error {
 
 	return err
 }
-
-// PruneWireguardConfig removes wgN.conf files of machines with
-// the corresponding ring disabled on all zones
-func (m *Zones) PruneWireguardConfig(ring int) error {
-	var err error
-
-	m.ForEachZone(func(z *Zone) bool {
-		err = z.PruneWireguardConfig(ring)
-		return err != nil
-	})
-
-	return err
-}
-
-// WriteWireguardKeys rewrites all wgN.{key,pub} files
-func (m *Zones) WriteWireguardKeys(ring int) error {
-	var err error
-
-	m.ForEachZone(func(z *Zone) bool {
-		err = z.WriteWireguardKeys(ring)
-		return err != nil
-	})
-
-	return err
-}

pkg/zones/zones.go

@@ -10,6 +10,22 @@ import (
 	"darvaza.org/resolver"
 )
 
+var (
+	_ MachineIterator = (*Zone)(nil)
+	_ MachineIterator = (*Zones)(nil)
+	_ ZoneIterator    = (*Zones)(nil)
+)
+
+// A MachineIterator is a set of Machines we can iterate on
+type MachineIterator interface {
+	ForEachMachine(func(*Machine) bool)
+}
+
+// A ZoneIterator is a set of Zones we can iterate on
+type ZoneIterator interface {
+	ForEachZone(func(*Zone) bool)
+}
+
 // Zone represents one zone in a cluster
 type Zone struct {
 	zones *Zones