From c96933784643f63a73b3daa3963f032d2f2e9d54 Mon Sep 17 00:00:00 2001
From: lfeng <lfeng1420@hotmail.com>
Date: Tue, 22 Jul 2025 18:02:21 +0800
Subject: [PATCH] fix: udp server may fail to send data to client when kcp
 enabled.

---
 event/kcp/hkcp.c | 23 ++++++++++++-----------
 event/kcp/hkcp.h |  4 ++--
 event/nio.c      |  2 +-
 event/rudp.c     |  4 ++--
 event/rudp.h     |  2 +-
 5 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/event/kcp/hkcp.c b/event/kcp/hkcp.c
index 2c9fe6c23..229594a5a 100644
--- a/event/kcp/hkcp.c
+++ b/event/kcp/hkcp.c
@@ -42,8 +42,8 @@ int hio_set_kcp(hio_t* io, kcp_setting_t* setting) {
     return 0;
 }
 
-kcp_t* hio_get_kcp(hio_t* io, uint32_t conv) {
-    rudp_entry_t* rudp = hio_get_rudp(io);
+kcp_t* hio_get_kcp(hio_t* io, uint32_t conv, struct sockaddr* addr) {
+    rudp_entry_t* rudp = hio_get_rudp(io, addr);
     assert(rudp != NULL);
     kcp_t* kcp = &rudp->kcp;
     if (kcp->ikcp != NULL) return kcp;
@@ -80,17 +80,18 @@ static void hio_write_kcp_event_cb(hevent_t* ev) {
     hio_t* io = (hio_t*)ev->userdata;
     hbuf_t* buf = (hbuf_t*)ev->privdata;
 
-    hio_write_kcp(io, buf->base, buf->len);
+    hio_write_kcp(io, buf->base + sizeof(sockaddr_u), buf->len - sizeof(sockaddr_u), (struct sockaddr*)buf->base);
 
     HV_FREE(buf);
 }
 
-static int hio_write_kcp_async(hio_t* io, const void* data, size_t len) {
+static int hio_write_kcp_async(hio_t* io, const void* data, size_t len, struct sockaddr* addr) {
     hbuf_t* buf = NULL;
-    HV_ALLOC(buf, sizeof(hbuf_t) + len);
+    HV_ALLOC(buf, sizeof(hbuf_t) + sizeof(sockaddr_u) + len);
     buf->base = (char*)buf + sizeof(hbuf_t);
-    buf->len = len;
-    memcpy(buf->base, data, len);
+    buf->len = len + sizeof(sockaddr_u);
+    memcpy(buf->base, addr, sizeof(sockaddr_u));
+    memcpy(buf->base + sizeof(sockaddr_u), data, len);
 
     hevent_t ev;
     memset(&ev, 0, sizeof(ev));
@@ -101,12 +102,12 @@ static int hio_write_kcp_async(hio_t* io, const void* data, size_t len) {
     return len;
 }
 
-int hio_write_kcp(hio_t* io, const void* buf, size_t len) {
+int hio_write_kcp(hio_t* io, const void* buf, size_t len, struct sockaddr* addr) {
     if (hv_gettid() != io->loop->tid) {
-        return hio_write_kcp_async(io, buf, len);
+        return hio_write_kcp_async(io, buf, len, addr);
     }
     IUINT32 conv = io->kcp_setting ? io->kcp_setting->conv : 0;
-    kcp_t* kcp = hio_get_kcp(io, conv);
+    kcp_t* kcp = hio_get_kcp(io, conv, addr);
     // printf("hio_write_kcp conv=%u=%u\n", conv, kcp->conv);
     int nsend = ikcp_send(kcp->ikcp, (const char*)buf, len);
     // printf("ikcp_send len=%d nsend=%d\n", (int)len, nsend);
@@ -120,7 +121,7 @@ int hio_write_kcp(hio_t* io, const void* buf, size_t len) {
 
 int hio_read_kcp (hio_t* io, void* buf, int readbytes) {
     IUINT32 conv = ikcp_getconv(buf);
-    kcp_t* kcp = hio_get_kcp(io, conv);
+    kcp_t* kcp = hio_get_kcp(io, conv, NULL);
     // printf("hio_read_kcp conv=%u=%u\n", conv, kcp->conv);
     if (kcp->conv != conv) {
         hloge("recv invalid kcp packet!");
diff --git a/event/kcp/hkcp.h b/event/kcp/hkcp.h
index ca9a0615d..f70e08774 100644
--- a/event/kcp/hkcp.h
+++ b/event/kcp/hkcp.h
@@ -21,9 +21,9 @@ typedef struct kcp_s {
 // NOTE: kcp_create in hio_get_kcp
 void kcp_release(kcp_t* kcp);
 
-kcp_t* hio_get_kcp  (hio_t* io, uint32_t conv);
+kcp_t* hio_get_kcp  (hio_t* io, uint32_t conv, struct sockaddr* addr DEFAULT(NULL));
 int    hio_read_kcp (hio_t* io, void* buf, int readbytes);
-int    hio_write_kcp(hio_t* io, const void* buf, size_t len);
+int    hio_write_kcp(hio_t* io, const void* buf, size_t len, struct sockaddr* addr DEFAULT(NULL));
 
 #endif
 
diff --git a/event/nio.c b/event/nio.c
index a71eeaa83..337299ac0 100644
--- a/event/nio.c
+++ b/event/nio.c
@@ -499,7 +499,7 @@ static int hio_write4 (hio_t* io, const void* buf, size_t len, struct sockaddr*
     hrecursive_mutex_lock(&io->write_mutex);
 #if WITH_KCP
     if (io->io_type == HIO_TYPE_KCP) {
-        nwrite = hio_write_kcp(io, buf, len);
+        nwrite = hio_write_kcp(io, buf, len, addr);
         // if (nwrite < 0) goto write_error;
         goto write_done;
     }
diff --git a/event/rudp.c b/event/rudp.c
index 6c7a6f373..76c29e554 100644
--- a/event/rudp.c
+++ b/event/rudp.c
@@ -136,8 +136,8 @@ void rudp_del(rudp_t* rudp, struct sockaddr* addr) {
     hmutex_unlock(&rudp->mutex);
 }
 
-rudp_entry_t* hio_get_rudp(hio_t* io) {
-    rudp_entry_t* rudp = rudp_get(&io->rudp, io->peeraddr);
+rudp_entry_t* hio_get_rudp(hio_t* io, struct sockaddr* addr) {
+    rudp_entry_t* rudp = rudp_get(&io->rudp, addr ? addr : io->peeraddr);
     rudp->io = io;
     return rudp;
 }
diff --git a/event/rudp.h b/event/rudp.h
index 0c30392ae..fbdedbe2b 100644
--- a/event/rudp.h
+++ b/event/rudp.h
@@ -45,7 +45,7 @@ rudp_entry_t* rudp_get(rudp_t* rudp, struct sockaddr* addr);
 void          rudp_del(rudp_t* rudp, struct sockaddr* addr);
 
 // rudp_get(&io->rudp, io->peeraddr)
-rudp_entry_t* hio_get_rudp(hio_t* io);
+rudp_entry_t* hio_get_rudp(hio_t* io, struct sockaddr* addr DEFAULT(NULL));
 
 #endif // WITH_RUDP