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Re-indent code and reduce code being complied on Solaris for anetKeepAlive (#12914) 

This is a follow-up PR for #12782, in which we introduced nested
preprocessor directives for TCP keep-alive on Solaris and added
redundant indentation for code. Besides, it could result in unreachable
code due to the lack of `#else` on the latest Solaris 11.4 where
`TCP_KEEPIDLE`, `TCP_KEEPINTVL`, and `TCP_KEEPCNT` are available. As a
result, this PR does three main things:

- To eliminate the redundant indention for C code in nested preprocessor
directives
- To add `#else` directives and move `TCP_KEEPALIVE_THRESHOLD` +
`TCP_KEEPALIVE_ABORT_THRESHOLD` settings under it, avoid unreachable
code and compiler warnings when `#if defined(TCP_KEEPIDLE) &&
defined(TCP_KEEPINTVL) && defined(TCP_KEEPCNT)` is met on Solaris 11.4
- To remove a few trailing whitespace in comments
This commit is contained in:
Andy Pan 2024-01-08 17:12:24 +08:00 committed by GitHub
parent c452e414a8
commit 50b8b99763
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 51 additions and 48 deletions
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99
src/anet.c
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@ -82,7 +82,7 @@ int anetSetBlock(char *err, int fd, int non_block) {
return ANET_ERR; return ANET_ERR;
} }
/* Check if this flag has been set or unset, if so, /* Check if this flag has been set or unset, if so,
* then there is no need to call fcntl to set/unset it again. */ * then there is no need to call fcntl to set/unset it again. */
if (!!(flags & O_NONBLOCK) == !!non_block) if (!!(flags & O_NONBLOCK) == !!non_block)
return ANET_OK; return ANET_OK;
@ -107,8 +107,8 @@ int anetBlock(char *err, int fd) {
return anetSetBlock(err,fd,0); return anetSetBlock(err,fd,0);
} }
/* Enable the FD_CLOEXEC on the given fd to avoid fd leaks. /* Enable the FD_CLOEXEC on the given fd to avoid fd leaks.
* This function should be invoked for fd's on specific places * This function should be invoked for fd's on specific places
* where fork + execve system calls are called. */ * where fork + execve system calls are called. */
int anetCloexec(int fd) { int anetCloexec(int fd) {
int r; int r;
@ -145,10 +145,10 @@ int anetKeepAlive(char *err, int fd, int interval)
int intvl; int intvl;
int cnt; int cnt;
/* There are platforms that are expected to support the full mechanism of TCP keep-alive, /* There are platforms that are expected to support the full mechanism of TCP keep-alive,
* we want the compiler to emit warnings of unused variables if the preprocessor directives * we want the compiler to emit warnings of unused variables if the preprocessor directives
* somehow fail, and other than those platforms, just omit these warnings if they happen. * somehow fail, and other than those platforms, just omit these warnings if they happen.
*/ */
#if !(defined(_AIX) || defined(__APPLE__) || defined(__DragonFly__) || \ #if !(defined(_AIX) || defined(__APPLE__) || defined(__DragonFly__) || \
defined(__FreeBSD__) || defined(__illumos__) || defined(__linux__) || \ defined(__FreeBSD__) || defined(__illumos__) || defined(__linux__) || \
defined(__NetBSD__) || defined(__sun)) defined(__NetBSD__) || defined(__sun))
@ -158,62 +158,63 @@ int anetKeepAlive(char *err, int fd, int interval)
UNUSED(cnt); UNUSED(cnt);
#endif #endif
/* The implementation of TCP keep-alive on Solaris/SmartOS is a bit unusual #ifdef __sun
* compared to other Unix-like systems. /* The implementation of TCP keep-alive on Solaris/SmartOS is a bit unusual
* Thus, we need to specialize it on Solaris. */ * compared to other Unix-like systems.
#ifdef __sun * Thus, we need to specialize it on Solaris.
/* There are two keep-alive mechanisms on Solaris: *
* - By default, the first keep-alive probe is sent out after a TCP connection is idle for two hours. * There are two keep-alive mechanisms on Solaris:
* If the peer does not respond to the probe within eight minutes, the TCP connection is aborted. * - By default, the first keep-alive probe is sent out after a TCP connection is idle for two hours.
* You can alter the interval for sending out the first probe using the socket option TCP_KEEPALIVE_THRESHOLD * If the peer does not respond to the probe within eight minutes, the TCP connection is aborted.
* You can alter the interval for sending out the first probe using the socket option TCP_KEEPALIVE_THRESHOLD
* in milliseconds or TCP_KEEPIDLE in seconds. * in milliseconds or TCP_KEEPIDLE in seconds.
* The system default is controlled by the TCP ndd parameter tcp_keepalive_interval. The minimum value is ten seconds. * The system default is controlled by the TCP ndd parameter tcp_keepalive_interval. The minimum value is ten seconds.
* The maximum is ten days, while the default is two hours. If you receive no response to the probe, * The maximum is ten days, while the default is two hours. If you receive no response to the probe,
* you can use the TCP_KEEPALIVE_ABORT_THRESHOLD socket option to change the time threshold for aborting a TCP connection. * you can use the TCP_KEEPALIVE_ABORT_THRESHOLD socket option to change the time threshold for aborting a TCP connection.
* The option value is an unsigned integer in milliseconds. The value zero indicates that TCP should never time out and * The option value is an unsigned integer in milliseconds. The value zero indicates that TCP should never time out and
* abort the connection when probing. The system default is controlled by the TCP ndd parameter tcp_keepalive_abort_interval. * abort the connection when probing. The system default is controlled by the TCP ndd parameter tcp_keepalive_abort_interval.
* The default is eight minutes. * The default is eight minutes.
*
* - The second implementation is activated if socket option TCP_KEEPINTVL and/or TCP_KEEPCNT are set. * - The second implementation is activated if socket option TCP_KEEPINTVL and/or TCP_KEEPCNT are set.
* The time between each consequent probes is set by TCP_KEEPINTVL in seconds. * The time between each consequent probes is set by TCP_KEEPINTVL in seconds.
* The minimum value is ten seconds. The maximum is ten days, while the default is two hours. * The minimum value is ten seconds. The maximum is ten days, while the default is two hours.
* The TCP connection will be aborted after certain amount of probes, which is set by TCP_KEEPCNT, without receiving response. * The TCP connection will be aborted after certain amount of probes, which is set by TCP_KEEPCNT, without receiving response.
*/ */
idle = interval; idle = interval;
if (idle < 10) idle = 10; // kernel expects at least 10 seconds if (idle < 10) idle = 10; // kernel expects at least 10 seconds
if (idle > 10*24*60*60) idle = 10*24*60*60; // kernel expects at most 10 days if (idle > 10*24*60*60) idle = 10*24*60*60; // kernel expects at most 10 days
/* `TCP_KEEPIDLE`, `TCP_KEEPINTVL`, and `TCP_KEEPCNT` were not available on Solaris
* until version 11.4, but let's take a chance here. */
#if defined(TCP_KEEPIDLE) && defined(TCP_KEEPINTVL) && defined(TCP_KEEPCNT)
if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle))) {
anetSetError(err, "setsockopt TCP_KEEPIDLE: %s\n", strerror(errno));
return ANET_ERR;
}
intvl = idle/3;
if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl))) {
anetSetError(err, "setsockopt TCP_KEEPINTVL: %s\n", strerror(errno));
return ANET_ERR;
}
cnt = 3;
if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt))) {
anetSetError(err, "setsockopt TCP_KEEPCNT: %s\n", strerror(errno));
return ANET_ERR;
}
return ANET_OK;
#endif
/* Fall back to the first implementation of tcp-alive mechanism for older Solaris, /* `TCP_KEEPIDLE`, `TCP_KEEPINTVL`, and `TCP_KEEPCNT` were not available on Solaris
* simulate the tcp-alive mechanism on other platforms via `TCP_KEEPALIVE_THRESHOLD` + `TCP_KEEPALIVE_ABORT_THRESHOLD`. * until version 11.4, but let's take a chance here. */
*/ #if defined(TCP_KEEPIDLE) && defined(TCP_KEEPINTVL) && defined(TCP_KEEPCNT)
if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(idle))) {
anetSetError(err, "setsockopt TCP_KEEPIDLE: %s\n", strerror(errno));
return ANET_ERR;
}
intvl = idle/3;
if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &intvl, sizeof(intvl))) {
anetSetError(err, "setsockopt TCP_KEEPINTVL: %s\n", strerror(errno));
return ANET_ERR;
}
cnt = 3;
if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(cnt))) {
anetSetError(err, "setsockopt TCP_KEEPCNT: %s\n", strerror(errno));
return ANET_ERR;
}
#else
/* Fall back to the first implementation of tcp-alive mechanism for older Solaris,
* simulate the tcp-alive mechanism on other platforms via `TCP_KEEPALIVE_THRESHOLD` + `TCP_KEEPALIVE_ABORT_THRESHOLD`.
*/
idle *= 1000; // kernel expects milliseconds idle *= 1000; // kernel expects milliseconds
if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE_THRESHOLD, &idle, sizeof(idle))) { if (setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE_THRESHOLD, &idle, sizeof(idle))) {
anetSetError(err, "setsockopt TCP_KEEPINTVL: %s\n", strerror(errno)); anetSetError(err, "setsockopt TCP_KEEPINTVL: %s\n", strerror(errno));
return ANET_ERR; return ANET_ERR;
} }
/* Note that the consequent probes will not be sent at equal intervals on Solaris, /* Note that the consequent probes will not be sent at equal intervals on Solaris,
* but will be sent using the exponential backoff algorithm. */ * but will be sent using the exponential backoff algorithm. */
intvl = idle/3; intvl = idle/3;
cnt = 3; cnt = 3;
@ -222,13 +223,15 @@ int anetKeepAlive(char *err, int fd, int interval)
anetSetError(err, "setsockopt TCP_KEEPCNT: %s\n", strerror(errno)); anetSetError(err, "setsockopt TCP_KEEPCNT: %s\n", strerror(errno));
return ANET_ERR; return ANET_ERR;
} }
#endif
return ANET_OK; return ANET_OK;
#endif #endif
#ifdef TCP_KEEPIDLE #ifdef TCP_KEEPIDLE
/* Default settings are more or less garbage, with the keepalive time /* Default settings are more or less garbage, with the keepalive time
* set to 7200 by default on Linux and other Unix-like systems. * set to 7200 by default on Linux and other Unix-like systems.
* Modify settings to make the feature actually useful. */ * Modify settings to make the feature actually useful. */
/* Send first probe after interval. */ /* Send first probe after interval. */