wireguard: adds wgN.conf parser

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

pkg/wireguard/config.go

@@ -0,0 +1,201 @@
+package wireguard
+
+import (
+	"encoding/base64"
+	"errors"
+	"io"
+	"net/netip"
+	"strconv"
+	"strings"
+
+	"darvaza.org/core"
+	"gopkg.in/gcfg.v1"
+)
+
+// Config represents a wgN.conf file
+type Config struct {
+	Interface InterfaceConfig
+	Peer      []PeerConfig
+}
+
+// GetAddress is a shortcut to the interface's address
+func (f *Config) GetAddress() netip.Addr {
+	return f.Interface.Address
+}
+
+// Peers tells how many peers are described
+func (f *Config) Peers() int {
+	return len(f.Peer)
+}
+
+// InterfaceConfig represents the [Interface] section
+type InterfaceConfig struct {
+	Address    netip.Addr
+	PrivateKey []byte
+	ListenPort uint16
+}
+
+// PeerConfig represents a [Peer] section
+type PeerConfig struct {
+	PublicKey  []byte
+	Endpoint   EndpointAddress
+	AllowedIPs []netip.Prefix
+}
+
+// EndpointAddress is a host:port pair to reach the Peer
+type EndpointAddress struct {
+	Name string
+	Port uint16
+}
+
+// FromString sets the EndpointAddress from a given "[host]:port"
+func (ep *EndpointAddress) FromString(s string) error {
+	host, port, err := core.SplitHostPort(s)
+	if err != nil {
+		return err
+	}
+
+	ep.Name = host
+
+	switch {
+	case port != "":
+		n, _ := strconv.ParseUint(port, 10, 16)
+		ep.Port = uint16(n)
+	default:
+		ep.Port = 0
+	}
+
+	return nil
+}
+
+type intermediateConfig struct {
+	Interface interfaceConfig
+	Peer      peersConfig
+}
+
+func (v *intermediateConfig) Export() (*Config, error) {
+	var out Config
+	var err error
+
+	// Interface
+	out.Interface, err = v.Interface.Export()
+	if err != nil {
+		return nil, err
+	}
+
+	// Peers
+	peers, ok := v.PeersCount()
+	if !ok {
+		return nil, errors.New("inconsistent Peer data")
+	}
+
+	for i := 0; i < peers; i++ {
+		p, err := v.ExportPeer(i)
+		if err != nil {
+			err = core.Wrapf(err, "Peer[%v]:", i)
+			return nil, err
+		}
+
+		out.Peer = append(out.Peer, p)
+	}
+
+	return &out, nil
+}
+
+type interfaceConfig struct {
+	Address    netip.Addr
+	PrivateKey string
+	ListenPort uint16
+}
+
+func (p interfaceConfig) Export() (InterfaceConfig, error) {
+	out := InterfaceConfig{
+		Address:    p.Address,
+		ListenPort: p.ListenPort,
+	}
+
+	b, err := base64.StdEncoding.DecodeString(p.PrivateKey)
+	if err != nil {
+		err = core.Wrap(err, "PrivateKey")
+		return InterfaceConfig{}, err
+	}
+
+	out.PrivateKey = b
+
+	return out, nil
+}
+
+type peersConfig struct {
+	PublicKey  []string
+	Endpoint   []string
+	AllowedIPs []string
+}
+
+func (v *intermediateConfig) ExportPeer(i int) (PeerConfig, error) {
+	var out PeerConfig
+
+	// Endpoint
+	s := v.Peer.Endpoint[i]
+	err := out.Endpoint.FromString(s)
+	if err != nil {
+		err = core.Wrap(err, "Endpoint")
+		return out, err
+	}
+
+	// PublicKey
+	s = v.Peer.PublicKey[i]
+	out.PublicKey, err = base64.StdEncoding.DecodeString(s)
+	if err != nil {
+		err = core.Wrap(err, "PublicKey")
+		return out, err
+	}
+
+	// AllowedIPs
+	s = v.Peer.AllowedIPs[i]
+	out.AllowedIPs, err = parseAllowedIPs(s)
+	if err != nil {
+		err = core.Wrap(err, "AllowedIPs")
+		return out, err
+	}
+
+	return out, nil
+}
+
+func parseAllowedIPs(data string) ([]netip.Prefix, error) {
+	var out []netip.Prefix
+
+	for _, s := range strings.Split(data, ",") {
+		s = strings.TrimSpace(s)
+		p, err := netip.ParsePrefix(s)
+		if err != nil {
+			return out, err
+		}
+
+		out = append(out, p)
+	}
+
+	return out, nil
+}
+
+func (v *intermediateConfig) PeersCount() (int, bool) {
+	c0 := len(v.Peer.Endpoint)
+	c1 := len(v.Peer.PublicKey)
+	c2 := len(v.Peer.AllowedIPs)
+
+	if c0 != c1 || c1 != c2 {
+		return 0, false
+	}
+
+	return c0, true
+}
+
+// NewConfigFromReader parses a wgN.conf file
+func NewConfigFromReader(r io.Reader) (*Config, error) {
+	temp := &intermediateConfig{}
+
+	if err := gcfg.ReadInto(temp, r); err != nil {
+		return nil, err
+	}
+
+	return temp.Export()
+}

pkg/wireguard/wireguard.go

@@ -0,0 +1,2 @@
+// Package wireguard deals with wireguard config
+package wireguard