nghttpx: Send CONNECTION_CLOSE if Retry token validation failed

src/shrpx_quic_connection_handler.cc

@@ -127,8 +127,10 @@ int QUICConnectionHandler::handle_packet(const UpstreamAddr *faddr,
         if (verify_retry_token(&odcid, hd.token.base, hd.token.len, &hd.dcid,
                                &remote_addr.su.sa, remote_addr.len,
                                secret.data()) != 0) {
-          // 2nd Retry packet is not allowed, so just drop it or send
+          // 2nd Retry packet is not allowed, so send CONNECTIONC_CLOE
-          // CONNECTIONC_CLOE with INVALID_TOKEN.
+          // with INVALID_TOKEN.
+          send_connection_close(faddr, version, &hd.dcid, &hd.scid, remote_addr,
+                                local_addr, NGTCP2_INVALID_TOKEN);
           return 0;
         }
 
@@ -406,6 +408,33 @@ int QUICConnectionHandler::send_stateless_reset(const UpstreamAddr *faddr,
                           0);
 }
 
+int QUICConnectionHandler::send_connection_close(
+    const UpstreamAddr *faddr, uint32_t version, const ngtcp2_cid *ini_dcid,
+    const ngtcp2_cid *ini_scid, const Address &remote_addr,
+    const Address &local_addr, uint64_t error_code) {
+  std::array<uint8_t, NGTCP2_DEFAULT_MAX_PKTLEN> buf;
+
+  auto nwrite = ngtcp2_crypto_write_connection_close(
+      buf.data(), buf.size(), version, ini_scid, ini_dcid, error_code);
+  if (nwrite < 0) {
+    LOG(ERROR) << "ngtcp2_crypto_write_connection_close failed";
+    return -1;
+  }
+
+  if (LOG_ENABLED(INFO)) {
+    LOG(INFO) << "Send Initial CONNECTION_CLOSE with error_code=" << log::hex
+              << error_code << log::dec
+              << " to remote=" << util::to_numeric_addr(&remote_addr)
+              << " dcid=" << util::format_hex(ini_scid->data, ini_scid->datalen)
+              << " scid="
+              << util::format_hex(ini_dcid->data, ini_dcid->datalen);
+  }
+
+  return quic_send_packet(faddr, &remote_addr.su.sa, remote_addr.len,
+                          &local_addr.su.sa, local_addr.len, buf.data(), nwrite,
+                          0);
+}
+
 void QUICConnectionHandler::add_connection_id(const ngtcp2_cid *cid,
                                               ClientHandler *handler) {
   auto key = make_cid_key(cid);

src/shrpx_quic_connection_handler.h

@@ -71,6 +71,15 @@ public:
   int send_stateless_reset(const UpstreamAddr *faddr, const uint8_t *dcid,
                            size_t dcidlen, const Address &remote_addr,
                            const Address &local_addr);
+  // Send Initial CONNECTION_CLOSE.  |ini_dcid| is the destination
+  // Connection ID which appeared in Client Initial packet.
+  // |ini_scid| is the source Connection ID which appeared in Client
+  // Initial packet.
+  int send_connection_close(const UpstreamAddr *faddr, uint32_t version,
+                            const ngtcp2_cid *ini_dcid,
+                            const ngtcp2_cid *ini_scid,
+                            const Address &remote_addr,
+                            const Address &local_addr, uint64_t error_code);
   ClientHandler *handle_new_connection(const UpstreamAddr *faddr,
                                        const Address &remote_addr,
                                        const Address &local_addr,