WIP: create new peers server-side

Creates a new peer server-side.
    - Gen keys
    - Allocate IP
    - Add to WG Link
    - Respond with a read wg config for the client to use

cmd/hvpn-node/hvpn-node.go

@@ -65,6 +65,7 @@ func run(ctx *cli.Context) {
     apiMux.HandleFunc("POST /peer", hvpnnode3.HandlePostPeer(wgLink))
     apiMux.HandleFunc("DELETE /peer/{pubkey}", hvpnnode3.HandleDeletePeer(wgLink))
     apiMux.HandleFunc("GET /peers", hvpnnode3.HandleGetPeers(wgLink))
+    apiMux.HandleFunc("GET /peer/new", hvpnnode3.HandleGetCreatePeer(wgLink))
 
     var handler http.Handler = apiMux
     handler = hvpnnode3.HttpAuthToken(handler, ctx.String("http-api-key"))

const.go

@@ -1,5 +1,17 @@
 package hvpnnode3
 
+import "net"
+
 const (
     CONTENT_JSON = "application/json"
+    CONTENT_OCTET = "application/octet-stream"
+    CONTENT_PLAIN_TEXT = "text/plain"
+    WG_CLIENT_MTU = 1380
+)
+
+var (
+    WG_CLIENT_DNS = []net.IP{
+        net.ParseIP("1.1.1.1"),
+        net.ParseIP("8.8.8.8"),
+    }
 )

handlers.go

@@ -8,12 +8,14 @@ import (
 	"log/slog"
 	"net/http"
 	"net/url"
+	"text/template"
 	"time"
 
 	"github.com/felixge/httpsnoop"
 	"github.com/google/uuid"
 
 	"gitea.hbanafa.com/HeshamTB/hvpn-node3/proto"
+	"gitea.hbanafa.com/HeshamTB/hvpn-node3/templates"
 )
 
 type CtxKey string
@@ -176,6 +178,33 @@ func HandleDeletePeer(wg *WGLink) http.HandlerFunc {
     }
 }
 
+func HandleGetCreatePeer(wg *WGLink) http.HandlerFunc {
+    return func(w http.ResponseWriter, r *http.Request) {
+        newPeer, err := wg.CreateNewPeer()
+        if err != nil {
+            slog.Error(err.Error())
+            w.WriteHeader(http.StatusInternalServerError)
+            return
+        }
+
+        tmpl, err := template.New("client.ini").Parse(templates.ClientINI)
+        if err != nil {
+            slog.Error(err.Error())
+            w.WriteHeader(http.StatusInternalServerError)
+            return
+        }
+
+        w.Header().Add("Content-Type", CONTENT_PLAIN_TEXT)
+        err = tmpl.Execute(w, newPeer)
+        if err != nil {
+            slog.Error(err.Error())
+        }
+
+        // TODO: Add peer to device
+
+    }
+}
+
 func HttpLogHandler2(h http.Handler) http.Handler {
     // https://blog.kowalczyk.info/article/e00e89c3841e4f8c8c769a78b8a90b47/logging-http-requests-in-go.html
     fn := func(w http.ResponseWriter, r* http.Request) {

link.go

@@ -2,6 +2,7 @@ package hvpnnode3
 
 import (
 	"errors"
+	"fmt"
 	"net"
 	"sync"
 	"time"
@@ -245,6 +246,64 @@ func (wg *WGLink) GetAllPeers() ([]wgtypes.Peer, error) {
     return dev.Peers, nil
 }
 
+func (wg *WGLink) GetPublicKey() (*wgtypes.Key, error) {
+    dev, err := wg.Device(wg.Name)
+    if err != nil {
+        return nil, err
+    }
+    return &dev.PublicKey, nil
+}
+
+// A peer config has it's own private key and the server node (peer section) endpoint and public key
+type NewPeer struct {
+    Peer wgtypes.Peer // The server as a peer 
+    PrivateKey wgtypes.Key
+    Address net.IP
+    DNS []net.IP
+    MTU uint
+
+    Endpoint string // Domain name and port
+}
+
+// Create a new peer. Used for server-side clinet config generation
+// Peer is not added to the wglink
+func (wg *WGLink) CreateNewPeer() (*NewPeer, error) {
+    dev, err := wg.Device(wg.Name)
+    if err != nil {
+        return nil, err
+    }
+
+    privKey, err := wgtypes.GeneratePrivateKey()
+    if err != nil {
+        return nil, err
+    }
+
+    serverPubkey, err := wg.GetPublicKey()
+    if err != nil {
+        return nil, err
+    }
+    
+    ip, err := wg.Allocate()
+    if err != nil {
+        return nil, err
+    }
+
+    peer := NewPeer{
+        Address: ip,
+        DNS: WG_CLIENT_DNS,
+        PrivateKey: privKey,
+        MTU: WG_CLIENT_MTU,
+        Peer: wgtypes.Peer{
+            PublicKey: *serverPubkey,
+            AllowedIPs: []net.IPNet{wg.Network()},
+        },
+        Endpoint: fmt.Sprintf("%s:%d", wg.Endpoint, dev.ListenPort),
+    }
+
+    return &peer, nil
+
+}
+
 func createARemovePeerCfg(publickey wgtypes.Key) wgtypes.Config {
     rmPeerCfg := wgtypes.PeerConfig{
         Remove: true,

templates/client.ini.tmpl

@@ -0,0 +1,12 @@
+[Interface]
+Address = {{ .Address }}/24
+PrivateKey = {{ .PrivateKey }} 
+DNS = {{$dnss := .DNS}}{{range $index, $element := .DNS}}{{if $index}}, {{end}}{{$element.String}}{{end}}
+MTU = {{ .MTU }}
+
+[Peer]
+PublicKey = {{ .Peer.PublicKey }}
+Endpoint = {{ .Endpoint }}
+AllowedIPs = 0.0.0.0/0, ::0/0
+PersistentKeepalive = 25
+

templates/templates.go

@@ -0,0 +1,6 @@
+package templates
+
+import _ "embed"
+
+//go:embed client.ini.tmpl 
+var ClientINI string