add example for kcp echo server

Author: yuliang

examples/CMakeLists.txt

@@ -78,7 +78,13 @@ if(WITH_KCP)
     add_executable(kcptun_server ${KCPTUN_SMUX_FILES} ${KCPTUN_SERVER_FILES})
     target_link_libraries(kcptun_server ${HV_LIBRARIES})
 
-    list(APPEND EXAMPLES kcptun_client kcptun_server)
+    add_executable(kcp_echo_server kcp_echo_server.c)
+    target_link_libraries(kcp_echo_server ${HV_LIBRARIES})
+
+    add_executable(kcp_echo_client kcp_echo_server.c)
+    target_link_libraries(kcp_echo_client ${HV_LIBRARIES})
+
+    list(APPEND EXAMPLES kcptun_client kcptun_server kcp_echo_server kcp_echo_client)
 endif()
 
 if(WITH_EVPP)

examples/kcp_echo_server.c

@@ -0,0 +1,127 @@
+/*
+ * kcp echo server
+ *
+ * @build   mkdir build && cmake -B build -S . -DWITH_KCP=ON && cmake --build build --clean-first
+ * @server  bin/kcp_echo_server
+ * @client  bin/kcp_echo_client
+ * @brief   kcp echo server/client combining with hsignal, htimer, supported for auto-reconnect
+ *
+ */
+#include <stdio.h>
+#include <stdint.h>
+#include <libgen.h>
+#include <signal.h>
+#include "hloop.h"
+#include "hsocket.h"
+
+#define FLAG_KCP_EXIT (1 << 0)
+static uint32_t flags;
+static char *host = "127.0.0.1";
+static int port = 8888;
+static kcp_setting_t kcp_setting;
+static htimer_t *timer = NULL;
+
+static hio_t *socket_open(hloop_t *loop);
+static void on_connect(hio_t *io);
+static void on_read(hio_t *io, void *buf, int readbytes);
+static void on_close(hio_t *io);
+
+static hio_t *socket_open(hloop_t *loop)
+{
+    intptr_t role = (intptr_t)hloop_userdata(loop);
+    hio_t *io = (role == HIO_SERVER_SIDE ? hloop_create_udp_server : hloop_create_udp_client)(loop, host, port);
+    hio_set_kcp(io, &kcp_setting);
+    hio_setcb_read(io, on_read);
+    hio_setcb_connect(io, on_connect);
+    hio_setcb_close(io, on_close);
+
+    hio_read(io);
+    if (role == HIO_CLIENT_SIDE)
+    {
+        hio_set_read_timeout(io, 2000);
+        hio_connect(io);
+    }
+
+    if (timer) hevent_set_userdata((hevent_t*)timer, io);
+    return io;
+}
+
+static void on_connect(hio_t *io)
+{
+    if (hio_is_connected(io)) hio_read(io);
+    char peeraddrstr[SOCKADDR_STRLEN] = {0};
+    printf("connect with %s\n", SOCKADDR_STR(hio_peeraddr(io), peeraddrstr));
+}
+
+static void on_read(hio_t *io, void *buf, int readbytes)
+{
+    char localaddrstr[SOCKADDR_STRLEN] = {0};
+    char peeraddrstr[SOCKADDR_STRLEN] = {0};
+    intptr_t role = (intptr_t)hloop_userdata(hevent_loop(io));
+
+    if (readbytes <= 0) {printf("errno on recv!\n"); return;}
+    printf("[%s] recv %d bytes from %s to %s--> buf: %.*s\n",
+        role == HIO_SERVER_SIDE ? "server" : "client",
+        readbytes,
+        SOCKADDR_STR(hio_peeraddr(io), peeraddrstr),
+        SOCKADDR_STR(hio_localaddr(io), localaddrstr),
+        readbytes,
+        (char*)buf);
+    if (role == HIO_SERVER_SIDE) hio_write(io, buf, readbytes);
+}
+
+static void on_close(hio_t *io)
+{
+    char peeraddrstr[SOCKADDR_STRLEN] = {0};
+    printf("disconnect from %s\n", SOCKADDR_STR(hio_peeraddr(io), peeraddrstr));
+    if (!(flags & FLAG_KCP_EXIT))
+    {
+        intptr_t role = (intptr_t)hloop_userdata(hevent_loop(io));
+        if (role == HIO_SERVER_SIDE) return;
+        hloop_t *loop = hevent_loop(io);
+        socket_open(loop);
+    }
+}
+
+static void signal_callback(hsignal_t* sig)
+{
+    flags |= FLAG_KCP_EXIT;
+    hloop_t *loop = hevent_loop(sig);
+    uint64_t signo = hevent_id(sig);
+    hloop_stop(loop);
+    printf("signo %ld arrived, exiting event loop at %p\n", signo, loop);
+}
+
+static void timer_callback(htimer_t* timer)
+{
+    hio_t *io = (hio_t*)hevent_userdata(timer);
+    intptr_t role = (intptr_t)hloop_userdata(hevent_loop(io));
+    if (hio_is_connected(io) && role == HIO_CLIENT_SIDE) hio_write(io, "hello world", 1500);
+}
+
+int main(int argc, char *argv[])
+{
+    int role = HIO_SERVER_SIDE;
+    if (strstr(basename(argv[0]), "server")) role = HIO_SERVER_SIDE;
+    if (strstr(basename(argv[0]), "client")) role = HIO_CLIENT_SIDE;
+
+    if (argc > 1) role = atoi(argv[1]);
+    if (argc > 2) host = argv[2];
+    if (argc > 3) port = atoi(argv[3]);
+    hloop_t *loop = hloop_new(0);
+    hloop_set_userdata(loop, (void*)(intptr_t)role);
+    timer = htimer_add(loop, timer_callback, 1000, INFINITE);
+    kcp_setting_init_with_fast_mode(&kcp_setting);
+    // more kcp settings like conv...
+    kcp_setting.rcv_bufsize = (3 * 1024);
+
+    socket_open(loop);
+
+    hsignal_add(loop, signal_callback, SIGINT);
+    hsignal_add(loop, signal_callback, SIGTERM);
+    hsignal_add(loop, signal_callback, SIGQUIT);
+
+    hloop_run(loop);
+    hloop_free(&loop);
+    return 0;
+}