fix: 静默 BrokenPipeError 因为后关server

.gitignore

@@ -18,3 +18,5 @@ c/bin
 /python/omnisocket.egg-info
 
 *.so*
+
+/.venv

cmd/b_side_video_sender.c

@@ -26,6 +26,8 @@
 
 #define WORKER_CONTROL_FD 3
 #define WORKER_TELEMETRY_FD 4
+#define WORKER_CONTROL_FD_ENV "OMNI_WORKER_CONTROL_FD"
+#define WORKER_TELEMETRY_FD_ENV "OMNI_WORKER_TELEMETRY_FD"
 #define NUM_BUFFERS 4
 #define CLEAR(x) memset(&(x), 0, sizeof(x))
 
@@ -238,11 +240,15 @@ static void telemetry_write_kcp_metrics(runtime_state_t *runtime, const kcp_conn
 
 static int load_worker_config(worker_config_t *cfg) {
     const char *server_addr = getenv(VIDEO_SERVER_ADDR_ENV);
+    const char *relay_addr = env_or_default(VIDEO_RELAY_ADDR_ENV, "");
 
     if (cfg == NULL) {
         errno = EINVAL;
         return -1;
     }
+    if ((server_addr == NULL || server_addr[0] == '\0') && relay_addr[0] != '\0') {
+        server_addr = relay_addr;
+    }
     if (server_addr == NULL || server_addr[0] == '\0') {
         fprintf(stderr, "%s is required\n", VIDEO_SERVER_ADDR_ENV);
         errno = EINVAL;
@@ -251,7 +257,7 @@ static int load_worker_config(worker_config_t *cfg) {
 
     CLEAR(*cfg);
     snprintf(cfg->server_addr, sizeof(cfg->server_addr), "%s", server_addr);
-    snprintf(cfg->relay_addr, sizeof(cfg->relay_addr), "%s", env_or_default(VIDEO_RELAY_ADDR_ENV, ""));
+    snprintf(cfg->relay_addr, sizeof(cfg->relay_addr), "%s", relay_addr);
     snprintf(cfg->bind_ip, sizeof(cfg->bind_ip), "%s", env_or_default(VIDEO_BIND_IP_ENV, ""));
     snprintf(cfg->bind_device, sizeof(cfg->bind_device), "%s", env_or_default(VIDEO_BIND_DEVICE_ENV, ""));
     snprintf(cfg->peer_id, sizeof(cfg->peer_id), "%s", env_or_default(VIDEO_PEER_ID_ENV, "peer-b-video"));
@@ -279,6 +285,7 @@ static int open_v4l2_device(const char *device) {
 
 static int init_v4l2_device(int fd, const worker_config_t *cfg) {
     struct v4l2_format fmt;
+    struct v4l2_streamparm parm;
 
     CLEAR(fmt);
     fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
@@ -291,6 +298,18 @@ static int init_v4l2_device(int fd, const worker_config_t *cfg) {
         perror("VIDIOC_S_FMT");
         return -1;
     }
+
+    CLEAR(parm);
+    parm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    if (cfg->initial_fps > 0 && ioctl(fd, VIDIOC_G_PARM, &parm) == 0) {
+        if ((parm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME) != 0U) {
+            parm.parm.capture.timeperframe.numerator = 1U;
+            parm.parm.capture.timeperframe.denominator = (unsigned int) cfg->initial_fps;
+            if (ioctl(fd, VIDIOC_S_PARM, &parm) < 0) {
+                perror("VIDIOC_S_PARM");
+            }
+        }
+    }
     return 0;
 }
 
@@ -353,6 +372,58 @@ static int queue_all_buffers(int fd, int num_buffers) {
     return 0;
 }
 
+static int dequeue_latest_buffer(int fd, struct v4l2_buffer *latest_buf) {
+    struct v4l2_buffer latest_local;
+    bool have_latest = false;
+
+    if (latest_buf == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    for (;;) {
+        struct v4l2_buffer current;
+        int dq_errno;
+
+        CLEAR(current);
+        current.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+        current.memory = V4L2_MEMORY_MMAP;
+        if (ioctl(fd, VIDIOC_DQBUF, &current) < 0) {
+            dq_errno = errno;
+            if (dq_errno == EINTR) {
+                continue;
+            }
+            if (dq_errno == EAGAIN) {
+                if (!have_latest) {
+                    errno = EAGAIN;
+                    return 1;
+                }
+                *latest_buf = latest_local;
+                return 0;
+            }
+            if (have_latest && ioctl(fd, VIDIOC_QBUF, &latest_local) < 0) {
+                perror("VIDIOC_QBUF");
+            }
+            errno = dq_errno;
+            return -1;
+        }
+
+        if (have_latest && ioctl(fd, VIDIOC_QBUF, &latest_local) < 0) {
+            int q_errno = errno;
+
+            perror("VIDIOC_QBUF");
+            if (ioctl(fd, VIDIOC_QBUF, &current) < 0) {
+                perror("VIDIOC_QBUF");
+            }
+            errno = q_errno;
+            return -1;
+        }
+
+        latest_local = current;
+        have_latest = true;
+    }
+}
+
 static AVCodecContext *create_mjpeg_decoder(const worker_config_t *cfg) {
     const AVCodec *decoder = avcodec_find_decoder(AV_CODEC_ID_MJPEG);
     AVCodecContext *ctx;
@@ -607,6 +678,8 @@ int main(void) {
     Buffer *buffers = NULL;
     int num_buffers = 0;
     int camera_fd = -1;
+    int control_fd = env_as_int(WORKER_CONTROL_FD_ENV, WORKER_CONTROL_FD);
+    int telemetry_fd = env_as_int(WORKER_TELEMETRY_FD_ENV, WORKER_TELEMETRY_FD);
     enum v4l2_buf_type stream_type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
     AVCodecContext *decoder = NULL;
     AVCodecContext *encoder = NULL;
@@ -636,8 +709,8 @@ int main(void) {
     runtime.jpeg_quality_qscale = cfg.initial_qscale;
     runtime.max_frame_bytes = cfg.initial_max_frame_bytes;
 
-    control_stream = fdopen(WORKER_CONTROL_FD, "r");
-    telemetry_stream = fdopen(WORKER_TELEMETRY_FD, "w");
+    control_stream = fdopen(control_fd, "r");
+    telemetry_stream = fdopen(telemetry_fd, "w");
     if (control_stream == NULL || telemetry_stream == NULL) {
         perror("fdopen worker control/telemetry");
         goto cleanup;
@@ -707,10 +780,6 @@ int main(void) {
         if (fps < 1) {
             fps = 1;
         }
-        if (next_deadline_ms > now_ms) {
-            usleep((useconds_t) ((next_deadline_ms - now_ms) * 1000.0));
-        }
-        next_deadline_ms = monotonic_ms() + (1000.0 / (double) fps);
 
         FD_ZERO(&fds);
         FD_SET(camera_fd, &fds);
@@ -725,10 +794,7 @@ int main(void) {
             continue;
         }
 
-        CLEAR(buf);
-        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-        buf.memory = V4L2_MEMORY_MMAP;
-        if (ioctl(camera_fd, VIDIOC_DQBUF, &buf) < 0) {
+        if (dequeue_latest_buffer(camera_fd, &buf) != 0) {
             if (errno == EAGAIN) {
                 continue;
             }
@@ -736,6 +802,13 @@ int main(void) {
             break;
         }
 
+        now_ms = monotonic_ms();
+        if (now_ms < next_deadline_ms) {
+            drop_reason = "paced_drop";
+            goto requeue_and_report;
+        }
+        next_deadline_ms = now_ms + (1000.0 / (double) fps);
+
         if (decode_mjpeg_frame(decoder, (uint8_t *) buffers[buf.index].start, (int) buf.bytesused, &decoded_frame) != 0) {
             drop_reason = "decode_failed";
             goto requeue_and_report;

config/b_side_omnidaemon.yaml

@@ -1,6 +1,6 @@
 transport:
-  server_addr: "81.70.156.140:10909"
-  relay_via: "106.55.173.235:10909"
+  server_addr: ""
+  relay_via: "81.70.156.140:10909"
   bind_ip: ""
   bind_device: ""
 
@@ -17,7 +17,7 @@ control_receiver:
   queue_capacity: 256
 
 video_sender:
-  enabled: false
+  enabled: true
   peer_id: "peer-b-video"
   target_peer: "peer-a-video"
   binary_path: "bin/b_side_video_sender"
@@ -39,7 +39,7 @@ daemon:
   worker_restart_delay_ms: 2000
 
 policy:
-  mode: "auto"
+  mode: "manual"
   health_window_ms: 2000
   green_srtt_ms: 30
   yellow_srtt_ms: 55

python/omnisocket_a_side/daemon.py

@@ -10,10 +10,11 @@ from pathlib import Path
 import queue
 import signal
 import socketserver
+import sys
 import threading
 import time
 from dataclasses import dataclass
-from datetime import UTC, datetime
+from datetime import datetime, timezone
 from http import HTTPStatus
 from http.server import BaseHTTPRequestHandler
 from typing import Any
@@ -25,13 +26,13 @@ from .control_codec import ANALOG_EVENT_CODES, EVENT_NAME_TO_ID, make_control_pa
 
 
 def utc_iso_now() -> str:
-    return datetime.now(UTC).isoformat(timespec="seconds").replace("+00:00", "Z")
+    return datetime.now(timezone.utc).isoformat(timespec="seconds").replace("+00:00", "Z")
 
 
 def load_omnisocket_api():
-    from omnisocket import CONTROL_DEFAULTS, MSG_TYPE_BINARY, Session, VIDEO_DEFAULTS
+    from omnisocket import CONTROL_DEFAULTS, MSG_TYPE_BINARY, MSG_TYPE_ERROR, Session, VIDEO_DEFAULTS
 
-    return CONTROL_DEFAULTS, MSG_TYPE_BINARY, Session, VIDEO_DEFAULTS
+    return CONTROL_DEFAULTS, MSG_TYPE_BINARY, MSG_TYPE_ERROR, Session, VIDEO_DEFAULTS
 
 
 def _merge_kcp_defaults(defaults: dict[str, Any], override: dict[str, Any]) -> dict[str, Any]:
@@ -49,7 +50,7 @@ def _load_config(config_path: str | None) -> dict[str, Any]:
         with path.open("r", encoding="utf-8") as file:
             raw = yaml.safe_load(file) or {}
 
-    control_defaults, _msg_type_binary, _session_cls, video_defaults = load_omnisocket_api()
+    control_defaults, _msg_type_binary, _msg_type_error, _session_cls, video_defaults = load_omnisocket_api()
 
     transport = dict(raw.get("transport", {}))
     control = dict(raw.get("control_sender", {}))
@@ -159,7 +160,7 @@ class QueuedControlEvent:
 
 class ControlSessionManager:
     def __init__(self, config: dict[str, Any]) -> None:
-        control_defaults, _msg_type_binary, session_cls, _video_defaults = load_omnisocket_api()
+        control_defaults, _msg_type_binary, _msg_type_error, session_cls, _video_defaults = load_omnisocket_api()
         transport = config["transport"]
         control_cfg = config["control_sender"]
         daemon_cfg = config["daemon"]
@@ -402,12 +403,13 @@ class ControlSessionManager:
 
 class VideoSessionManager:
     def __init__(self, config: dict[str, Any]) -> None:
-        _control_defaults, msg_type_binary, session_cls, video_defaults = load_omnisocket_api()
+        _control_defaults, msg_type_binary, msg_type_error, session_cls, video_defaults = load_omnisocket_api()
         transport = config["transport"]
         video_cfg = config["video_receiver"]
         daemon_cfg = config["daemon"]
 
         self._msg_type_binary = msg_type_binary
+        self._msg_type_error = msg_type_error
         self._session_cls = session_cls
         self._connect_kwargs = {
             "server_addr": transport["server_addr"],
@@ -516,9 +518,12 @@ class VideoSessionManager:
                     meta = session.recv_into(buffer, timeout_ms=200)
                     if meta is None:
                         continue
-                    if meta.get("msg_type") != self._msg_type_binary:
-                        continue
+                    msg_type = int(meta.get("msg_type", -1))
                     frame = bytes(buffer[: int(meta["body_len"])])
+                    if msg_type != self._msg_type_binary:
+                        self._disconnect(self._describe_unexpected_message(msg_type, frame))
+                        time.sleep(0.2)
+                        break
                     jpeg_frame = self._extract_jpeg_frame(frame)
                     if jpeg_frame is None:
                         with self._lock:
@@ -534,6 +539,14 @@ class VideoSessionManager:
                 self._disconnect(str(error))
                 time.sleep(0.2)
 
+    def _describe_unexpected_message(self, msg_type: int, payload: bytes) -> str:
+        detail = payload.decode("utf-8", errors="replace").strip()
+        if msg_type == self._msg_type_error:
+            return f"video session rejected by server: {detail or 'unknown error'}"
+        if detail:
+            return f"received unexpected video message type {msg_type}: {detail}"
+        return f"received unexpected video message type {msg_type}"
+
     def _connect(self) -> None:
         session = self._session_cls()
         try:
@@ -958,8 +971,11 @@ class OmniDaemonHTTPHandler(BaseHTTPRequestHandler):
         self.send_header("Content-Length", str(len(payload)))
         self.send_header("Cache-Control", "no-store")
         self.send_header("Connection", "keep-alive")
-        self.end_headers()
-        self.wfile.write(payload)
+        try:
+            self.end_headers()
+            self.wfile.write(payload)
+        except (BrokenPipeError, ConnectionResetError):
+            return
 
 
 class ASideOmniDaemon:
@@ -1043,6 +1059,15 @@ def main(argv: list[str] | None = None) -> None:
     args = parser.parse_args(argv)
 
     app = ASideOmniDaemon(config_path=args.config_path)
+    print(
+        (
+            "A-side OmniDaemon starting "
+            f"(config={app._config['config_path']}, "
+            f"socket={app._config['daemon']['socket_path']})"
+        ),
+        file=sys.stderr,
+        flush=True,
+    )
 
     def _handle_signal(_signum: int, _frame: Any) -> None:
         app.stop()
@@ -1052,7 +1077,17 @@ def main(argv: list[str] | None = None) -> None:
     signal.signal(signal.SIGTERM, _handle_signal)
 
     try:
-        app.serve_forever()
+        app.start()
+        print(
+            (
+                "A-side OmniDaemon ready "
+                f"(state: curl --unix-socket {app.socket_path} http://localhost/v1/state)"
+            ),
+            file=sys.stderr,
+            flush=True,
+        )
+        assert app._server is not None
+        app._server.serve_forever()
     except KeyboardInterrupt:
         pass
     finally:

python/omnisocket_b_side/daemon.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 import argparse
 import copy
 from dataclasses import dataclass
-from datetime import UTC, datetime
+from datetime import datetime, timezone
 from http import HTTPStatus
 from http.server import BaseHTTPRequestHandler
 import json
@@ -16,6 +16,7 @@ import signal
 import socket
 import socketserver
 import subprocess
+import sys
 import threading
 import time
 from typing import Any
@@ -34,13 +35,13 @@ from . import (
 
 
 def utc_iso_now() -> str:
-    return datetime.now(UTC).isoformat(timespec="seconds").replace("+00:00", "Z")
+    return datetime.now(timezone.utc).isoformat(timespec="seconds").replace("+00:00", "Z")
 
 
 def load_omnisocket_api():
-    from omnisocket import CONTROL_DEFAULTS, MSG_TYPE_BINARY, Session
+    from omnisocket import CONTROL_DEFAULTS, MSG_TYPE_BINARY, MSG_TYPE_ERROR, Session
 
-    return CONTROL_DEFAULTS, MSG_TYPE_BINARY, Session
+    return CONTROL_DEFAULTS, MSG_TYPE_BINARY, MSG_TYPE_ERROR, Session
 
 
 def _merge_kcp_defaults(defaults: dict[str, Any], override: dict[str, Any]) -> dict[str, Any]:
@@ -114,7 +115,7 @@ def _load_config(config_path: str | None) -> dict[str, Any]:
         with path.open("r", encoding="utf-8") as file:
             raw = yaml.safe_load(file) or {}
 
-    control_defaults, _msg_type_binary, _session_cls = load_omnisocket_api()
+    control_defaults, _msg_type_binary, _msg_type_error, _session_cls = load_omnisocket_api()
     transport = dict(raw.get("transport", {}))
     control = dict(raw.get("control_receiver", {}))
     video = dict(raw.get("video_sender", {}))
@@ -192,12 +193,13 @@ def _load_config(config_path: str | None) -> dict[str, Any]:
 
 class ControlRecvManager:
     def __init__(self, config: dict[str, Any]) -> None:
-        control_defaults, msg_type_binary, session_cls = load_omnisocket_api()
+        control_defaults, msg_type_binary, msg_type_error, session_cls = load_omnisocket_api()
         transport = config["transport"]
         control_cfg = config["control_receiver"]
         daemon_cfg = config["daemon"]
 
         self._msg_type_binary = msg_type_binary
+        self._msg_type_error = msg_type_error
         self._session_cls = session_cls
         self._connect_kwargs = {
             "server_addr": transport["server_addr"],
@@ -306,6 +308,7 @@ class ControlRecvManager:
             if msg_type != self._msg_type_binary:
                 with self._lock:
                     self._ignored_non_binary += 1
+                self._disconnect(self._describe_unexpected_message(msg_type, payload))
                 continue
             if len(payload) != CONTROL_PACKET_STRUCT.size:
                 with self._lock:
@@ -345,6 +348,14 @@ class ControlRecvManager:
             except Exception:
                 pass
 
+    def _describe_unexpected_message(self, msg_type: int, payload: bytes) -> str:
+        detail = payload.decode("utf-8", errors="replace").strip()
+        if msg_type == self._msg_type_error:
+            return f"control session rejected by server: {detail or 'unknown error'}"
+        if detail:
+            return f"received unexpected control message type {msg_type}: {detail}"
+        return f"received unexpected control message type {msg_type}"
+
     def _enqueue_packet(self, payload: bytes) -> None:
         try:
             self._queue.put_nowait(payload)
@@ -540,6 +551,16 @@ class VideoWorkerManager:
     def start(self) -> None:
         if not self._enabled:
             return
+        if not os.path.exists(self._video_cfg["binary_path"]):
+            print(
+                (
+                    "B-side video worker binary missing: "
+                    f"{self._video_cfg['binary_path']} "
+                    "(run `make b_side_video_sender` in OmniSocketGo)"
+                ),
+                file=sys.stderr,
+                flush=True,
+            )
         self._thread.start()
 
     def stop(self) -> None:
@@ -650,16 +671,6 @@ class VideoWorkerManager:
         command_read_fd, command_write_fd = os.pipe()
         telemetry_read_fd, telemetry_write_fd = os.pipe()
 
-        def _preexec() -> None:
-            os.dup2(command_read_fd, 3)
-            os.dup2(telemetry_write_fd, 4)
-            for fd in (command_read_fd, command_write_fd, telemetry_read_fd, telemetry_write_fd):
-                if fd not in (3, 4):
-                    try:
-                        os.close(fd)
-                    except OSError:
-                        pass
-
         env = dict(os.environ)
         env.update(
             {
@@ -675,6 +686,8 @@ class VideoWorkerManager:
                 "OMNI_VIDEO_OUTPUT_WIDTH": str(self._video_cfg["output_width"]),
                 "OMNI_VIDEO_OUTPUT_HEIGHT": str(self._video_cfg["output_height"]),
                 "OMNI_VIDEO_STATS_INTERVAL_MS": str(self._video_cfg["stats_interval_ms"]),
+                "OMNI_WORKER_CONTROL_FD": str(command_read_fd),
+                "OMNI_WORKER_TELEMETRY_FD": str(telemetry_write_fd),
             }
         )
         with self._lock:
@@ -692,7 +705,6 @@ class VideoWorkerManager:
                 env=env,
                 close_fds=True,
                 pass_fds=(command_read_fd, telemetry_write_fd),
-                preexec_fn=_preexec,
             )
         except Exception as error:  # pragma: no cover - runtime integration
             for fd in (command_read_fd, command_write_fd, telemetry_read_fd, telemetry_write_fd):
@@ -1196,8 +1208,11 @@ class OmniDaemonHTTPHandler(BaseHTTPRequestHandler):
         self.send_header("Content-Length", str(len(body)))
         self.send_header("Cache-Control", "no-store")
         self.send_header("Connection", "keep-alive")
-        self.end_headers()
-        self.wfile.write(body)
+        try:
+            self.end_headers()
+            self.wfile.write(body)
+        except (BrokenPipeError, ConnectionResetError):
+            return
 
 
 class BSideOmniDaemon:
@@ -1259,6 +1274,14 @@ class BSideOmniDaemon:
             daemon=True,
         )
         self._server_thread.start()
+        print(
+            (
+                "B-side OmniDaemon ready "
+                f"(state: curl --unix-socket {self.socket_path} http://localhost/v1/state)"
+            ),
+            file=sys.stderr,
+            flush=True,
+        )
         self._server_thread.join()
 
     def get_state(self) -> dict[str, Any]:
@@ -1299,6 +1322,17 @@ def main(argv: list[str] | None = None) -> None:
     args = parser.parse_args(argv)
 
     app = BSideOmniDaemon(config_path=args.config_path)
+    print(
+        (
+            "B-side OmniDaemon starting "
+            f"(config={app._config['config_path']}, "
+            f"socket={app._config['daemon']['socket_path']}, "
+            f"ctrl_socket={app._config['daemon']['ctrl_socket_path']}, "
+            f"video_enabled={app._config['video_sender']['enabled']})"
+        ),
+        file=sys.stderr,
+        flush=True,
+    )
 
     def _handle_signal(_signum: int, _frame: Any) -> None:
         app.stop()

python/setup.py

@@ -36,6 +36,9 @@ setup(
     name="omnisocket",
     version="0.1.0",
     packages=["omnisocket", "omnisocket_a_side", "omnisocket_b_side"],
+    install_requires=[
+        "PyYAML>=6.0",
+    ],
     entry_points={
         "console_scripts": [
             "omnisocket-a-side-daemon=omnisocket_a_side.daemon:main",

src/server_udp_relay.c

@@ -5,6 +5,13 @@
 
 #define UDP_RELAY_BUF_SIZE (64U * 1024U)
 
+typedef struct udp_relay_client_entry {
+    struct udp_relay_client_entry *next;
+    uint32_t conv;
+    struct sockaddr_storage addr;
+    socklen_t addr_len;
+} udp_relay_client_entry_t;
+
 struct udp_relay {
     int downstream_fd;
     int upstream_fd;
@@ -12,9 +19,10 @@ struct udp_relay {
     socklen_t upstream_addr_len;
     char downstream_local_addr[OMNI_MAX_ADDR_TEXT];
     char upstream_local_addr[OMNI_MAX_ADDR_TEXT];
-    struct sockaddr_storage client_addr;
-    socklen_t client_addr_len;
-    int has_client;
+    struct sockaddr_storage last_client_addr;
+    socklen_t last_client_addr_len;
+    int has_last_client;
+    udp_relay_client_entry_t *clients;
     pthread_mutex_t lock;
     pthread_mutex_t log_mu;
     pthread_mutex_t state_mu;
@@ -131,22 +139,55 @@ static void udp_relay_note_result(udp_relay_t *relay, int rc, int errnum) {
     pthread_mutex_unlock(&relay->state_mu);
 }
 
-static void udp_relay_record_client(udp_relay_t *relay, const struct sockaddr_storage *addr, socklen_t addr_len) {
+static udp_relay_client_entry_t *udp_relay_find_client_locked(udp_relay_t *relay, uint32_t conv) {
+    udp_relay_client_entry_t *entry;
+
+    for (entry = relay->clients; entry != NULL; entry = entry->next) {
+        if (entry->conv == conv) {
+            return entry;
+        }
+    }
+    return NULL;
+}
+
+static void udp_relay_record_client(udp_relay_t *relay, int has_conv, uint32_t conv, const struct sockaddr_storage *addr, socklen_t addr_len) {
     pthread_mutex_lock(&relay->lock);
-    memcpy(&relay->client_addr, addr, sizeof(*addr));
-    relay->client_addr_len = addr_len;
-    relay->has_client = 1;
+    memcpy(&relay->last_client_addr, addr, sizeof(*addr));
+    relay->last_client_addr_len = addr_len;
+    relay->has_last_client = 1;
+    if (has_conv) {
+        udp_relay_client_entry_t *entry = udp_relay_find_client_locked(relay, conv);
+        if (entry == NULL) {
+            entry = (udp_relay_client_entry_t *) calloc(1, sizeof(*entry));
+            if (entry != NULL) {
+                entry->conv = conv;
+                entry->next = relay->clients;
+                relay->clients = entry;
+            }
+        }
+        if (entry != NULL) {
+            memcpy(&entry->addr, addr, sizeof(*addr));
+            entry->addr_len = addr_len;
+        }
+    }
     pthread_mutex_unlock(&relay->lock);
 }
 
-static int udp_relay_copy_client(udp_relay_t *relay, struct sockaddr_storage *addr, socklen_t *addr_len) {
-    int has_client;
+static int udp_relay_copy_client(udp_relay_t *relay, int has_conv, uint32_t conv, struct sockaddr_storage *addr, socklen_t *addr_len) {
+    int has_client = 0;
 
     pthread_mutex_lock(&relay->lock);
-    has_client = relay->has_client;
-    if (has_client) {
-        memcpy(addr, &relay->client_addr, sizeof(*addr));
-        *addr_len = relay->client_addr_len;
+    if (has_conv) {
+        udp_relay_client_entry_t *entry = udp_relay_find_client_locked(relay, conv);
+        if (entry != NULL) {
+            memcpy(addr, &entry->addr, sizeof(*addr));
+            *addr_len = entry->addr_len;
+            has_client = 1;
+        }
+    } else if (relay->has_last_client) {
+        memcpy(addr, &relay->last_client_addr, sizeof(*addr));
+        *addr_len = relay->last_client_addr_len;
+        has_client = 1;
     }
     pthread_mutex_unlock(&relay->lock);
     return has_client;
@@ -160,6 +201,8 @@ static void *udp_relay_forward_downstream_to_upstream(void *arg) {
         struct sockaddr_storage source;
         socklen_t source_len = sizeof(source);
         ssize_t n = recvfrom(relay->downstream_fd, buffer, sizeof(buffer), 0, (struct sockaddr *) &source, &source_len);
+        int has_conv = 0;
+        uint32_t conv = 0;
 
         if (n < 0) {
             int errnum = errno;
@@ -174,7 +217,8 @@ static void *udp_relay_forward_downstream_to_upstream(void *arg) {
             return NULL;
         }
 
-        udp_relay_record_client(relay, &source, source_len);
+        udp_relay_parse_kcp_summary(buffer, (size_t) n, &has_conv, &conv, NULL);
+        udp_relay_record_client(relay, has_conv, conv, &source, source_len);
         udp_relay_print_packet(relay, "relay_downstream_rx", relay->downstream_local_addr, &source, source_len, buffer, (size_t) n);
         for (;;) {
             if (send(relay->upstream_fd, buffer, (size_t) n, 0) >= 0) {
@@ -205,6 +249,8 @@ static void *udp_relay_forward_upstream_to_downstream(void *arg) {
         struct sockaddr_storage client_addr;
         socklen_t client_addr_len = 0;
         ssize_t n = recv(relay->upstream_fd, buffer, sizeof(buffer), 0);
+        int has_conv = 0;
+        uint32_t conv = 0;
 
         if (n < 0) {
             int errnum = errno;
@@ -220,7 +266,8 @@ static void *udp_relay_forward_upstream_to_downstream(void *arg) {
         }
 
         udp_relay_print_packet(relay, "relay_upstream_rx", relay->upstream_local_addr, &relay->upstream_addr, relay->upstream_addr_len, buffer, (size_t) n);
-        if (!udp_relay_copy_client(relay, &client_addr, &client_addr_len)) {
+        udp_relay_parse_kcp_summary(buffer, (size_t) n, &has_conv, &conv, NULL);
+        if (!udp_relay_copy_client(relay, has_conv, conv, &client_addr, &client_addr_len)) {
             udp_relay_print_packet(relay, "relay_upstream_drop_no_client", relay->upstream_local_addr, &relay->upstream_addr, relay->upstream_addr_len, buffer, (size_t) n);
             continue;
         }
@@ -404,11 +451,18 @@ int udp_relay_close(udp_relay_t *relay) {
 }
 
 void udp_relay_free(udp_relay_t *relay) {
+    udp_relay_client_entry_t *entry;
+    udp_relay_client_entry_t *next;
+
     if (relay == NULL) {
         return;
     }
     udp_relay_close(relay);
     udp_relay_join_threads(relay);
+    for (entry = relay->clients; entry != NULL; entry = next) {
+        next = entry->next;
+        free(entry);
+    }
     pthread_mutex_destroy(&relay->lock);
     pthread_mutex_destroy(&relay->log_mu);
     pthread_cond_destroy(&relay->state_cond);