* [PATCH] tcp.7: tcp_syncookies: It is now an integer [0, 2]
@ 2020-12-07 17:08 Alejandro Colomar
2020-12-11 8:32 ` Michael Kerrisk (man-pages)
0 siblings, 1 reply; 5+ messages in thread
From: Alejandro Colomar @ 2020-12-07 17:08 UTC (permalink / raw)
To: mtk.manpages
Cc: Alejandro Colomar, linux-man, Philip Rowlands, Eric Dumazet,
Hannes Frederic Sowa, David S . Miller
Since Linux kernel 3.12, tcp_syncookies can have the value 2,
which sends out cookies unconditionally.
Related kernel commits:
5ad37d5deee1ff7150a2d0602370101de158ad86
d8513df2598e5142f8a5c4724f28411936e1dfc7
Reported-by: Philip Rowlands <linux-kernel@dimebar.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: David S. Miller <davem@davemloft.net>
---
man7/tcp.7 | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/man7/tcp.7 b/man7/tcp.7
index d983a8f9a..591f73d8d 100644
--- a/man7/tcp.7
+++ b/man7/tcp.7
@@ -830,12 +830,11 @@ The maximum number of times a SYN/ACK segment
for a passive TCP connection will be retransmitted.
This number should not be higher than 255.
.TP
-.IR tcp_syncookies " (Boolean; since Linux 2.2)"
+.IR tcp_syncookies " (integer; default: 1; since Linux 2.2)"
.\" Since 2.1.43
Enable TCP syncookies.
The kernel must be compiled with
.BR CONFIG_SYN_COOKIES .
-Send out syncookies when the syn backlog queue of a socket overflows.
The syncookies feature attempts to protect a
socket from a SYN flood attack.
This should be used as a last resort, if at all.
@@ -849,6 +848,17 @@ For recommended alternatives see
.IR tcp_synack_retries ,
and
.IR tcp_abort_on_overflow .
+Set to one of the following values:
+.RS
+.IP 0 3
+Disable TCP syncookies.
+.IP 1
+Send out syncookies when the syn backlog queue of a socket overflows.
+.IP 2
+.\" commit 5ad37d5deee1ff7150a2d0602370101de158ad86
+Send out syncookies unconditionally.
+This can be useful for network testing.
+.RE
.TP
.IR tcp_timestamps " (integer; default: 1; since Linux 2.2)"
.\" Since 2.1.36
--
2.29.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] tcp.7: tcp_syncookies: It is now an integer [0, 2]
2020-12-07 17:08 [PATCH] tcp.7: tcp_syncookies: It is now an integer [0, 2] Alejandro Colomar
@ 2020-12-11 8:32 ` Michael Kerrisk (man-pages)
2020-12-11 18:03 ` Alejandro Colomar (man-pages)
0 siblings, 1 reply; 5+ messages in thread
From: Michael Kerrisk (man-pages) @ 2020-12-11 8:32 UTC (permalink / raw)
To: Alejandro Colomar
Cc: mtk.manpages, linux-man, Philip Rowlands, Eric Dumazet,
Hannes Frederic Sowa, David S . Miller
Hi Alex,
On 12/7/20 6:08 PM, Alejandro Colomar wrote:
> Since Linux kernel 3.12, tcp_syncookies can have the value 2,
> which sends out cookies unconditionally.
>
> Related kernel commits:
> 5ad37d5deee1ff7150a2d0602370101de158ad86
> d8513df2598e5142f8a5c4724f28411936e1dfc7
>
> Reported-by: Philip Rowlands <linux-kernel@dimebar.com>
> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
> Cc: David S. Miller <davem@davemloft.net>
> ---
> man7/tcp.7 | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/man7/tcp.7 b/man7/tcp.7
> index d983a8f9a..591f73d8d 100644
> --- a/man7/tcp.7
> +++ b/man7/tcp.7
> @@ -830,12 +830,11 @@ The maximum number of times a SYN/ACK segment
> for a passive TCP connection will be retransmitted.
> This number should not be higher than 255.
> .TP
> -.IR tcp_syncookies " (Boolean; since Linux 2.2)"
> +.IR tcp_syncookies " (integer; default: 1; since Linux 2.2)"
> .\" Since 2.1.43
> Enable TCP syncookies.
> The kernel must be compiled with
> .BR CONFIG_SYN_COOKIES .
> -Send out syncookies when the syn backlog queue of a socket overflows.
> The syncookies feature attempts to protect a
> socket from a SYN flood attack.
> This should be used as a last resort, if at all.
> @@ -849,6 +848,17 @@ For recommended alternatives see
> .IR tcp_synack_retries ,
> and
> .IR tcp_abort_on_overflow .
> +Set to one of the following values:
> +.RS
> +.IP 0 3
> +Disable TCP syncookies.
> +.IP 1
> +Send out syncookies when the syn backlog queue of a socket overflows.
> +.IP 2
I think it's helpful to let the reader know that this is a more
recent feature. So, better:
.IP 2 (since Linux 3.12)
Thanks,
Michael
> +.\" commit 5ad37d5deee1ff7150a2d0602370101de158ad86
> +Send out syncookies unconditionally.
> +This can be useful for network testing.
> +.RE
> .TP
> .IR tcp_timestamps " (integer; default: 1; since Linux 2.2)"
> .\" Since 2.1.36
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tcp.7: tcp_syncookies: It is now an integer [0, 2]
2020-12-11 8:32 ` Michael Kerrisk (man-pages)
@ 2020-12-11 18:03 ` Alejandro Colomar (man-pages)
2020-12-11 18:47 ` [PATCH v2] " Alejandro Colomar
0 siblings, 1 reply; 5+ messages in thread
From: Alejandro Colomar (man-pages) @ 2020-12-11 18:03 UTC (permalink / raw)
To: Michael Kerrisk (man-pages)
Cc: linux-man, Philip Rowlands, Eric Dumazet, Hannes Frederic Sowa,
David S . Miller
Hi Michael,
On 12/11/20 9:32 AM, Michael Kerrisk (man-pages) wrote:[...]
>> +.IP 2
>
> I think it's helpful to let the reader know that this is a more
> recent feature. So, better:
>
> .IP 2 (since Linux 3.12)
Sure!
Thanks,
Alex
>
> Thanks,
>
> Michael
>
>> +.\" commit 5ad37d5deee1ff7150a2d0602370101de158ad86
>> +Send out syncookies unconditionally.
>> +This can be useful for network testing.
>> +.RE
>> .TP
>> .IR tcp_timestamps " (integer; default: 1; since Linux 2.2)"
>> .\" Since 2.1.36
>>
>
>
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] tcp.7: tcp_syncookies: It is now an integer [0, 2]
2020-12-11 18:03 ` Alejandro Colomar (man-pages)
@ 2020-12-11 18:47 ` Alejandro Colomar
2020-12-11 21:30 ` Michael Kerrisk (man-pages)
0 siblings, 1 reply; 5+ messages in thread
From: Alejandro Colomar @ 2020-12-11 18:47 UTC (permalink / raw)
To: mtk.manpages
Cc: Alejandro Colomar, linux-man, Philip Rowlands, Eric Dumazet,
Hannes Frederic Sowa, David S . Miller
Since Linux kernel 3.12, tcp_syncookies can have the value 2,
which sends out cookies unconditionally.
Related kernel commits:
5ad37d5deee1ff7150a2d0602370101de158ad86
d8513df2598e5142f8a5c4724f28411936e1dfc7
Reported-by: Philip Rowlands <linux-kernel@dimebar.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: David S. Miller <davem@davemloft.net>
---
man7/tcp.7 | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/man7/tcp.7 b/man7/tcp.7
index d983a8f9a..cce8dd910 100644
--- a/man7/tcp.7
+++ b/man7/tcp.7
@@ -830,12 +830,11 @@ The maximum number of times a SYN/ACK segment
for a passive TCP connection will be retransmitted.
This number should not be higher than 255.
.TP
-.IR tcp_syncookies " (Boolean; since Linux 2.2)"
+.IR tcp_syncookies " (integer; default: 1; since Linux 2.2)"
.\" Since 2.1.43
Enable TCP syncookies.
The kernel must be compiled with
.BR CONFIG_SYN_COOKIES .
-Send out syncookies when the syn backlog queue of a socket overflows.
The syncookies feature attempts to protect a
socket from a SYN flood attack.
This should be used as a last resort, if at all.
@@ -849,6 +848,18 @@ For recommended alternatives see
.IR tcp_synack_retries ,
and
.IR tcp_abort_on_overflow .
+Set to one of the following values:
+.RS
+.IP 0 3
+Disable TCP syncookies.
+.IP 1
+Send out syncookies when the syn backlog queue of a socket overflows.
+.IP 2
+(since Linux 3.12)
+.\" commit 5ad37d5deee1ff7150a2d0602370101de158ad86
+Send out syncookies unconditionally.
+This can be useful for network testing.
+.RE
.TP
.IR tcp_timestamps " (integer; default: 1; since Linux 2.2)"
.\" Since 2.1.36
--
2.29.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v2] tcp.7: tcp_syncookies: It is now an integer [0, 2]
2020-12-11 18:47 ` [PATCH v2] " Alejandro Colomar
@ 2020-12-11 21:30 ` Michael Kerrisk (man-pages)
0 siblings, 0 replies; 5+ messages in thread
From: Michael Kerrisk (man-pages) @ 2020-12-11 21:30 UTC (permalink / raw)
To: Alejandro Colomar
Cc: mtk.manpages, linux-man, Philip Rowlands, Eric Dumazet,
Hannes Frederic Sowa, David S . Miller
Hi Alex,
On 12/11/20 7:47 PM, Alejandro Colomar wrote:
> Since Linux kernel 3.12, tcp_syncookies can have the value 2,
> which sends out cookies unconditionally.
Thanks. Patch applied.
Cheers,
Michael
> Related kernel commits:
> 5ad37d5deee1ff7150a2d0602370101de158ad86
> d8513df2598e5142f8a5c4724f28411936e1dfc7
>
> Reported-by: Philip Rowlands <linux-kernel@dimebar.com>
> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
> Cc: David S. Miller <davem@davemloft.net>
> ---
> man7/tcp.7 | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/man7/tcp.7 b/man7/tcp.7
> index d983a8f9a..cce8dd910 100644
> --- a/man7/tcp.7
> +++ b/man7/tcp.7
> @@ -830,12 +830,11 @@ The maximum number of times a SYN/ACK segment
> for a passive TCP connection will be retransmitted.
> This number should not be higher than 255.
> .TP
> -.IR tcp_syncookies " (Boolean; since Linux 2.2)"
> +.IR tcp_syncookies " (integer; default: 1; since Linux 2.2)"
> .\" Since 2.1.43
> Enable TCP syncookies.
> The kernel must be compiled with
> .BR CONFIG_SYN_COOKIES .
> -Send out syncookies when the syn backlog queue of a socket overflows.
> The syncookies feature attempts to protect a
> socket from a SYN flood attack.
> This should be used as a last resort, if at all.
> @@ -849,6 +848,18 @@ For recommended alternatives see
> .IR tcp_synack_retries ,
> and
> .IR tcp_abort_on_overflow .
> +Set to one of the following values:
> +.RS
> +.IP 0 3
> +Disable TCP syncookies.
> +.IP 1
> +Send out syncookies when the syn backlog queue of a socket overflows.
> +.IP 2
> +(since Linux 3.12)
> +.\" commit 5ad37d5deee1ff7150a2d0602370101de158ad86
> +Send out syncookies unconditionally.
> +This can be useful for network testing.
> +.RE
> .TP
> .IR tcp_timestamps " (integer; default: 1; since Linux 2.2)"
> .\" Since 2.1.36
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-12-11 22:35 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-07 17:08 [PATCH] tcp.7: tcp_syncookies: It is now an integer [0, 2] Alejandro Colomar
2020-12-11 8:32 ` Michael Kerrisk (man-pages)
2020-12-11 18:03 ` Alejandro Colomar (man-pages)
2020-12-11 18:47 ` [PATCH v2] " Alejandro Colomar
2020-12-11 21:30 ` Michael Kerrisk (man-pages)
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