189 lines
6.9 KiB
Diff
189 lines
6.9 KiB
Diff
diff --git a/evutil.c b/evutil.c
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index 9817f08..e1803de 100644
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--- a/evutil.c
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+++ b/evutil.c
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@@ -2763,3 +2763,137 @@ evutil_free_globals_(void)
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evutil_free_secure_rng_globals_();
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evutil_free_sock_err_globals();
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}
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+
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+int
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+evutil_set_tcp_keepalive(evutil_socket_t fd, int on, int timeout)
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+{
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+ int idle;
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+ int intvl;
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+ int cnt;
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+
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+ /* Prevent compiler from complaining unused variables warnings. */
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+ (void) idle;
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+ (void) intvl;
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+ (void) cnt;
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+
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+ if (timeout <= 0)
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+ return 0;
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+
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+ if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)))
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+ return -1;
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+ if (!on)
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+ return 0;
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+
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+ /* Unlike Unix-like OS's, TCP keep-alive mechanism on Windows is kind of a mess,
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+ * setting TCP_KEEPIDLE, TCP_KEEPINTVL and TCP_KEEPCNT on Windows could be a bit tricky.
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+ * Check out https://learn.microsoft.com/en-us/windows/win32/winsock/sio-keepalive-vals,
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+ * https://learn.microsoft.com/en-us/windows/win32/winsock/ipproto-tcp-socket-options.
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+ * These three options are not available until Windows 10, version 1709 where we set them
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+ * by `setsockopt` (slightly different from Unix-like OS's pattern), while on older Windows,
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+ * we have to use `WSAIoctl` instead.
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+ * Therefore, we skip setting those three options on Windows for now.
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+ * TODO(panjf2000): enable the full TCP keep-alive mechanism on Windows when we find a feasible way to do it.
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+ */
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+#ifndef _WIN32
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+
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+ /* The implementation of TCP keep-alive on Solaris/SmartOS is a bit unusual
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+ * compared to other Unix-like systems.
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+ * Thus, we need to specialize it on Solaris.
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+ */
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+#ifdef __sun
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+ /* There are two keep-alive mechanisms on Solaris:
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+ * - By default, the first keep-alive probe is sent out after a TCP connection is idle for two hours.
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+ * If the peer does not respond to the probe within eight minutes, the TCP connection is aborted.
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+ * You can alter the interval for sending out the first probe using the socket option TCP_KEEPALIVE_THRESHOLD
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+ * in milliseconds or TCP_KEEPIDLE in seconds.
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+ * The system default is controlled by the TCP ndd parameter tcp_keepalive_interval. The minimum value is ten seconds.
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+ * The maximum is ten days, while the default is two hours. If you receive no response to the probe,
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+ * you can use the TCP_KEEPALIVE_ABORT_THRESHOLD socket option to change the time threshold for aborting a TCP connection.
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+ * The option value is an unsigned integer in milliseconds. The value zero indicates that TCP should never time out and
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+ * abort the connection when probing. The system default is controlled by the TCP ndd parameter tcp_keepalive_abort_interval.
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+ * The default is eight minutes.
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+ *
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+ * - The second implementation is activated if socket option TCP_KEEPINTVL and/or TCP_KEEPCNT are set.
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+ * The time between each consequent probes is set by TCP_KEEPINTVL in seconds.
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+ * The minimum value is ten seconds. The maximum is ten days, while the default is two hours.
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+ * The TCP connection will be aborted after certain amount of probes, which is set by TCP_KEEPCNT, without receiving response.
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+ */
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+
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+ idle = timeout;
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+ /* Kernel expects at least 10 seconds. */
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+ if (idle < 10)
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+ idle = 10;
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+ /* Kernel expects at most 10 days. */
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+ if (idle > 10*24*60*60)
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+ idle = 10*24*60*60;
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+
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+ /* `TCP_KEEPIDLE`, `TCP_KEEPINTVL`, and `TCP_KEEPCNT` were not available on Solaris
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+ * until version 11.4, but let's gamble here.
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+ */
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+#if defined(TCP_KEEPIDLE) && defined(TCP_KEEPINTVL) && defined(TCP_KEEPCNT)
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle)))
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+ return -1;
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+ intvl = idle/3;
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl)))
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+ return -1;
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+ cnt = 3;
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt)))
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+ return -1;
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+ return 0;
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+#endif
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+
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+ /* Fall back to the first implementation of tcp-alive mechanism for older Solaris,
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+ * simulate the tcp-alive mechanism on other platforms via `TCP_KEEPALIVE_THRESHOLD` + `TCP_KEEPALIVE_ABORT_THRESHOLD`.
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+ */
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+ idle *= 1000; /* kernel expects milliseconds */
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE_THRESHOLD, &idle, sizeof(idle)))
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+ return -1;
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+
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+ /* Note that the consequent probes will not be sent at equal intervals on Solaris,
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+ * but will be sent using the exponential backoff algorithm.
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+ */
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+ intvl = idle/3;
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+ cnt = 3;
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+ int time_to_abort = intvl * cnt;
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE_ABORT_THRESHOLD, &time_to_abort, sizeof(time_to_abort)))
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+ return -1;
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+
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+ return 0;
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+#endif
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+
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+#ifdef TCP_KEEPIDLE
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+ idle = timeout;
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle)))
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+ return -1;
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+#elif defined(TCP_KEEPALIVE)
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+ /* Darwin/macOS uses TCP_KEEPALIVE in place of TCP_KEEPIDLE. */
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+ idle = timeout;
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE, &idle, sizeof(idle)))
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+ return -1;
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+#endif
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+
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+#ifdef TCP_KEEPINTVL
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+ /* Set the interval between individual keep-alive probes as timeout / 3
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+ * and the maximum number of keepalive probes as 3 to make it double timeout
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+ * before aborting a dead connection.
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+ */
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+ intvl = timeout/3;
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+ if (intvl == 0)
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+ intvl = 1;
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl)))
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+ return -1;
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+#endif
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+
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+#ifdef TCP_KEEPCNT
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+ /* Set the maximum number of keepalive probes as 3 to collaborate with
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+ * TCP_KEEPINTVL, see the previous comment.
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+ */
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+ cnt = 3;
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+ if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt)))
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+ return -1;
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+#endif
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+
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+#endif /* !_WIN32 */
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+
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+ return 0;
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+}
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diff --git a/http.c b/http.c
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index 53951cb..1ad60f8 100644
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--- a/http.c
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+++ b/http.c
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@@ -4417,7 +4417,7 @@ create_bind_socket_nonblock(struct evutil_addrinfo *ai, int reuse)
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{
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evutil_socket_t fd;
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- int on = 1, r;
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+ int r;
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int serrno;
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/* Create listen socket */
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@@ -4428,7 +4428,8 @@ create_bind_socket_nonblock(struct evutil_addrinfo *ai, int reuse)
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return (-1);
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}
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- if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, sizeof(on))<0)
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+ /* TODO(panjf2000): make this TCP keep-alive value configurable */
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+ if (evutil_set_tcp_keepalive(fd, 1, 300) < 0)
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goto out;
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if (reuse) {
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if (evutil_make_listen_socket_reuseable(fd) < 0)
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diff --git a/include/event2/util.h b/include/event2/util.h
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index 02aa7ba..688b641 100644
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--- a/include/event2/util.h
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+++ b/include/event2/util.h
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@@ -469,6 +469,18 @@ int evutil_closesocket(evutil_socket_t sock);
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EVENT2_EXPORT_SYMBOL
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int evutil_make_tcp_listen_socket_deferred(evutil_socket_t sock);
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+/** Do platform-specific operations to set/unset TCP keep-alive options
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+ * TCP_KEEPIDLE, TCP_KEEPINTVL and TCP_KEEPCNT on a socket.
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+ *
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+ * @param sock The socket to be set TCP keep-alive
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+ * @param on nonzero value to enable TCP keep-alive, 0 to disable
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+ * @param timeout The timeout in seconds with no activity until
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+ * the first keepalive probe is sent
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+ * @return 0 on success, -1 on failure
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+*/
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+EVENT2_EXPORT_SYMBOL
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+int evutil_set_tcp_keepalive(evutil_socket_t sock, int on, int timeout);
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+
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#ifdef _WIN32
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/** Return the most recent socket error. Not idempotent on all platforms. */
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#define EVUTIL_SOCKET_ERROR() WSAGetLastError()
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