On 2011/07/04 22:44, Claudio Jeker wrote:
> But this is correct since because of the reception of a TCP keepalive
> response we do not consider the TCP session idle anymore
Ah, this is what I was missing.
> and keepintvl
> comes only into play when the other side does not respond.
> At least that is how think keepalives are supposed to work.
Now I remembered to look at Stevens vol 2 and this matches his
interpretation too. I withdraw the tcp_input.c part of my diff.
Index: lib/libc/gen/sysctl.3
===================================================================
RCS file: /cvs/src/lib/libc/gen/sysctl.3,v
retrieving revision 1.203
diff -u -p -r1.203 sysctl.3
--- lib/libc/gen/sysctl.3 27 Jun 2011 17:43:03 -0000 1.203
+++ lib/libc/gen/sysctl.3 4 Jul 2011 22:12:30 -0000
@@ -1575,6 +1575,10 @@ Time to keep alive the initial SYN packe
Time after a keepalive probe is sent until, in the absence of any response,
another probe is sent.
See also tcp.slowhz.
+.It Li tcp.always_keepalive
+Act as if the option
+.Dv SO_KEEPALIVE
+was set on all TCP sockets.
.It Li tcp.mssdflt
The maximum segment size that is used as default for non-local connections.
The default value is 512.
Index: sys/netinet/tcp_timer.c
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_timer.c,v
retrieving revision 1.45
diff -u -p -r1.45 tcp_timer.c
--- sys/netinet/tcp_timer.c 3 Jul 2010 04:44:51 -0000 1.45
+++ sys/netinet/tcp_timer.c 4 Jul 2011 22:12:30 -0000
@@ -55,6 +55,7 @@
#include <netinet/ip_icmp.h>
#include <netinet/tcp_seq.h>
+int tcp_always_keepalive;
int tcp_keepidle;
int tcp_keepintvl;
int tcp_maxpersistidle; /* max idle time in persist */
@@ -435,7 +436,8 @@ tcp_timer_keep(void *arg)
tcpstat.tcps_keeptimeo++;
if (TCPS_HAVEESTABLISHED(tp->t_state) == 0)
goto dropit;
- if (tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE &&
+ if ((tcp_always_keepalive ||
+ tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) &&
tp->t_state <= TCPS_CLOSING) {
if ((tcp_maxidle > 0) &&
((tcp_now - tp->t_rcvtime) >= tcp_keepidle + tcp_maxidle))
Index: sys/netinet/tcp_timer.h
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_timer.h,v
retrieving revision 1.12
diff -u -p -r1.12 tcp_timer.h
--- sys/netinet/tcp_timer.h 8 Nov 2008 12:54:58 -0000 1.12
+++ sys/netinet/tcp_timer.h 4 Jul 2011 22:12:30 -0000
@@ -145,6 +145,7 @@ typedef void (*tcp_timer_func_t)(void *)
extern const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS];
extern int tcptv_keep_init;
+extern int tcp_always_keepalive; /* assume SO_KEEPALIVE is always set */
extern int tcp_keepidle; /* time before keepalive probes begin */
extern int tcp_keepintvl; /* time between keepalive probes */
extern int tcp_maxidle; /* time to drop after starting
probes */
Index: sys/netinet/tcp_usrreq.c
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_usrreq.c,v
retrieving revision 1.107
diff -u -p -r1.107 tcp_usrreq.c
--- sys/netinet/tcp_usrreq.c 28 Apr 2011 09:56:27 -0000 1.107
+++ sys/netinet/tcp_usrreq.c 4 Jul 2011 22:12:30 -0000
@@ -909,6 +909,10 @@ tcp_sysctl(name, namelen, oldp, oldlenp,
case TCPCTL_DROP:
return (tcp_ident(oldp, oldlenp, newp, newlen, 1));
+ case TCPCTL_ALWAYS_KEEPALIVE:
+ return (sysctl_int(oldp, oldlenp, newp, newlen,
+ &tcp_always_keepalive));
+
#ifdef TCP_ECN
case TCPCTL_ECN:
return (sysctl_int(oldp, oldlenp, newp, newlen,
Index: sys/netinet/tcp_var.h
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_var.h,v
retrieving revision 1.98
diff -u -p -r1.98 tcp_var.h
--- sys/netinet/tcp_var.h 7 Jan 2011 17:50:42 -0000 1.98
+++ sys/netinet/tcp_var.h 4 Jul 2011 22:12:30 -0000
@@ -473,7 +473,8 @@ struct tcpstat {
#define TCPCTL_DROP 19 /* drop tcp connection */
#define TCPCTL_SACKHOLE_LIMIT 20 /* max entries for tcp sack queues */
#define TCPCTL_STATS 21 /* TCP statistics */
-#define TCPCTL_MAXID 22
+#define TCPCTL_ALWAYS_KEEPALIVE 22 /* assume SO_KEEPALIVE is always set
*/
+#define TCPCTL_MAXID 23
#define TCPCTL_NAMES { \
{ 0, 0 }, \
@@ -497,7 +498,8 @@ struct tcpstat {
{ "reasslimit", CTLTYPE_INT }, \
{ "drop", CTLTYPE_STRUCT }, \
{ "sackholelimit", CTLTYPE_INT }, \
- { "stats", CTLTYPE_STRUCT } \
+ { "stats", CTLTYPE_STRUCT }, \
+ { "always_keepalive", CTLTYPE_INT } \
}
#define TCPCTL_VARS { \
Index: sbin/sysctl/sysctl.8
===================================================================
RCS file: /cvs/src/sbin/sysctl/sysctl.8,v
retrieving revision 1.159
diff -u -p -r1.159 sysctl.8
--- sbin/sysctl/sysctl.8 24 Jun 2011 19:47:48 -0000 1.159
+++ sbin/sysctl/sysctl.8 4 Jul 2011 22:12:30 -0000
@@ -257,6 +257,7 @@ and a few require a kernel compiled with
.It net.inet.tcp.keepinittime integer yes
.It net.inet.tcp.keepidle integer yes
.It net.inet.tcp.keepintvl integer yes
+.It net.inet.tcp.always_keepalive integer yes
.It net.inet.tcp.slowhz integer no
.It net.inet.tcp.baddynamic array yes
.It net.inet.tcp.sack integer yes
