Merge pull request #17 from iamxvbaba/dev

fix: sync lenient DC-ID validation for key exchange

internal/mtprotoedge/server.go

@@ -303,6 +303,21 @@ type Options struct {
 
 	// DC 是本 server 的 DC ID。默认 2。
 	DC int
+	// StrictDC turns on exact DC-ID validation for the permanent-key exchange
+	// (default off = lenient). telesrv is always a single physical backend —
+	// there is no real multi-DC federation behind it — but self-hosted client
+	// forks commonly run in "single-server backend" mode, where dc_id 1..5 all
+	// alias to this one server so that any old data referencing a specific
+	// dc_id still resolves correctly. When a client adds a new local account it
+	// picks its own starting dc_id (its usual multi-DC load-spreading
+	// behavior, unrelated to which physical server it's actually talking to)
+	// — that choice is not guaranteed to equal our configured DC. Strict
+	// validation would reject those accounts with "-444 wrong dc_id" even
+	// though they are connecting to the right (and only) server; dc_id is a
+	// client-side routing label here, not part of key derivation, so
+	// accepting the mismatch does not weaken the exchange. The switch exists
+	// for a hypothetical future real multi-DC deployment.
+	StrictDC bool
 	// RSAKey 是 server RSA 私钥，用于密钥交换。nil 时无法完成握手。
 	RSAKey *rsa.PrivateKey
 	// AuthKeys 持久化 auth key。默认内存实现。
@@ -482,6 +497,7 @@ type Server struct {
 	outboundScratchPool      *outboundScratchPool
 
 	dc        int
+	strictDC  bool
 	key       exchange.PrivateKey
 	authKeys  store.AuthKeyStore
 	conns     *SessionManager
@@ -533,6 +549,7 @@ func New(opts Options) *Server {
 		outboundControlBudget:    newOutboundTrackedBudget(defaultOutboundControlMaxBytes),
 		outboundScratchPool:      newOutboundScratchPool(opts.OutboundWriteGlobalMaxBytes),
 		dc:                       opts.DC,
+		strictDC:                 opts.StrictDC,
 		key:                      exchange.PrivateKey{RSA: opts.RSAKey},
 		authKeys:                 opts.AuthKeys,
 		conns:                    conns,