Page MenuHomeFreeBSD
Differential D10840

Add libc++experimental.a for std::experimental support
ClosedPublic
Actions

Authored by dim on May 21 2017, 11:58 AM.
Tags
None
Referenced Files
Unknown Object (File)
Wed, Apr 16, 8:55 PM
Unknown Object (File)
Mon, Apr 14, 3:03 AM
Unknown Object (File)
Sun, Apr 13, 10:50 PM
Unknown Object (File)
Sat, Apr 12, 4:50 AM
Unknown Object (File)
Fri, Mar 28, 8:18 AM
Unknown Object (File)
Thu, Mar 27, 5:32 AM
Unknown Object (File)
Mar 10 2025, 2:26 PM
Unknown Object (File)
Mar 5 2025, 9:24 PM
View All 99 Files
Subscribers
imp

Details

Reviewers
ed
emaste
Commits
rS344213: Merge clang 7.0.1 and several follow-up changes
rS318594: Add libc++experimental.a for std::experimental support
Summary

Follow-up to D10839, add a separate libc++experimental.a for supporting
std::experimental features. This library is purposefully static, and
must be explicitly linked into programs using -lc++experimental.

NOTE: there is NO WARRANTY as to any stability or continuing existence of the features in the experimental C++ library!

Diff Detail

Repository
rS FreeBSD src repository - subversion
Lint
Lint Not Applicable
Unit
Tests Not Applicable

Event Timeline

dim created this revision.May 21 2017, 11:58 AM
Herald added a subscriber: imp. · View Herald TranscriptMay 21 2017, 11:58 AM
dim mentioned this in D10839: Make std::experimental::filesystem work..May 21 2017, 11:59 AM
ed edited edge metadata.May 21 2017, 12:57 PM

Would it make sense to let this new library be responsible for installing the experimental/ headers as well?

dim added a comment.May 21 2017, 1:12 PM
In D10840#224632, @ed wrote:

Would it make sense to let this new library be responsible for installing the experimental/ headers as well?

Maybe, but it also adds complexity for no good reason. There is also experimental/ functionality which is header-only, and therefore does not need any runtime support.

Upstream installs all of these from one Makefile, which I would also like to do, but it isn't possible with bsd.lib.mk, unfortunately.

ed accepted this revision.May 21 2017, 1:13 PM
This revision is now accepted and ready to land.May 21 2017, 1:13 PM
Closed by commit rS318594: Add libc++experimental.a for std::experimental support (authored by dim). · Explain WhyMay 21 2017, 5:07 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathSize
head/
lib/
2 lines
libc++experimental/
29 lines
tools/
build/
mk/
1 line

Diff 28636

View Options

head/lib/Makefile

Show All 28 Lines
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE. .\" SUCH DAMAGE.
.\" .\"
.\" From: @(#)tcp.4 8.1 (Berkeley) 6/5/93 .\" From: @(#)tcp.4 8.1 (Berkeley) 6/5/93
.\" $FreeBSD$ .\" $FreeBSD$
.\" .\"
.Dd October 7, 2022 .Dd October 13, 2022
.Dt TCP 4 .Dt TCP 4
.Os .Os
.Sh NAME .Sh NAME
.Nm tcp .Nm tcp
.Nd Internet Transmission Control Protocol .Nd Internet Transmission Control Protocol
.Sh SYNOPSIS .Sh SYNOPSIS
.In sys/types.h .In sys/types.h
.In sys/socket.h .In sys/socket.h
▲ Show 20 Lines • Show All 459 Lines • ▼ Show 20 Lines
Outgoing connections will request ECN. Outgoing connections will request ECN.
.It 2 .It 2
Allow incoming connections to request ECN. Allow incoming connections to request ECN.
Outgoing connections will not request ECN. Outgoing connections will not request ECN.
(default) (default)
.It 3 .It 3
Negotiate on incoming connection for Accurate ECN, ECN, or no ECN. Negotiate on incoming connection for Accurate ECN, ECN, or no ECN.
Outgoing connections will request Accurate ECN and fall back to Outgoing connections will request Accurate ECN and fall back to
ECN depending on the capabilities of the server. ECN depending on the capabilities of the remote host.
pauamma_gundo.comUnsubmitted
Done
Inline Actions
Outgoing connections will request Accurate ECN and fall back to
- ECN depending on the capabilities of the server.
+ ECN depending on the capabilities of the remote host.
.It 4
pauamma_gundo.com:
.It 4 .It 4
Negotiate on incoming connection for Accurate ECN, ECN, or no ECN. Negotiate on incoming connection for Accurate ECN, ECN, or no ECN.
Outgoing connections will not request ECN. Outgoing connections will not request ECN.
.El
.It Va ecn.generalized
Enable sending all segments as ECN capable transport,
including SYN, SYN/ACK, and retransmissions.
This may only be enabled when ECN support itself is also active.
Disabling ECN support will disable this feature automatically.
Settings:
.Bl -tag -compact
.It 0
Regular RFC3168 operation.
Send only new data segments as ECN capable transport.
(default)
.It 1
Support generalized ECN (ECN++), and send all segments of an ECN-enabled
session as ECN capable transport.
Also control packets to non-established and non-listening ports are
identically marked, if outgoing sessions would request ECN.
.El .El
.It Va ecn.maxretries .It Va ecn.maxretries
Number of retries (SYN or SYN/ACK retransmits) before disabling ECN on a Number of retries (SYN or SYN/ACK retransmits) before disabling ECN on a
specific connection. specific connection.
This is needed to help with connection establishment This is needed to help with connection establishment
when a broken firewall is in the network path. when a broken firewall is in the network path.
.It Va fast_finwait2_recycle .It Va fast_finwait2_recycle
Recycle Recycle
.Tn TCP .Tn TCP
.Dv FIN_WAIT_2 .Dv FIN_WAIT_2
pauamma_gundo.comUnsubmitted
Done
Inline Actions
including SYN, SYN/ACK, and retransmissions.
- This may only be enabled, when ECN support itself is also active.
+ This may only be enabled when ECN support itself is also active.
Disabling ECN support will disable this feature automatically.
pauamma_gundo.com:
connections faster when the socket is marked as connections faster when the socket is marked as
.Dv SBS_CANTRCVMORE .Dv SBS_CANTRCVMORE
(no user process has the socket open, data received on (no user process has the socket open, data received on
the socket cannot be read). the socket cannot be read).
The timeout used here is The timeout used here is
.Va finwait2_timeout . .Va finwait2_timeout .
.It Va fastopen.acceptany .It Va fastopen.acceptany
pauamma_gundo.comUnsubmitted
Done
Inline Actions
Regular RFC3168 operation.
- Send only new data segements as ECN capable transport.
- (default)
+ Send only new data segments as ECN capable transport (default).
.It 1

Typo and move full stop to a more natural place.

pauamma_gundo.com: Typo and move full stop to a more natural place.
When non-zero, all client-supplied TFO cookies will be considered to be valid. When non-zero, all client-supplied TFO cookies will be considered to be valid.
The default is 0. The default is 0.
.It Va fastopen.autokey .It Va fastopen.autokey
When this and When this and
.Va net.inet.tcp.fastopen.server_enable .Va net.inet.tcp.fastopen.server_enable
bcrUnsubmitted
Done
Inline Actions

s/identially/identically/

bcr: s/identially/identically/
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Can you explain what you mean by that? I'm arguably not the indended audience, but if I don't understand it, there's a chance some of the intended audience and or some interested readers won't either.

pauamma_gundo.com: Can you explain what you mean by that? I'm arguably not the indended audience, but if I don't…
rscheffAuthorUnsubmitted
Done
Inline Actions

When a host receives a TCP packet to a port which is not listening, or no connection exists, or the header information is in some other way not acceptable, the host may respond with a RST (reset) packet. Some of these RST packets are sent from "regular" TCP processing (e.g. outside the sequence window) and others from non-open ports. Making these distinctable by carrying different markings - depending which code path was sending them - would give clues as to what ports/services may be reachable, and give rise to more targetted attacks.
As part if this change, when introducing this new capability (modified TCP header markings for sessions), the irregular codepath is addressed too, such that a 3rd party can not deduct which of the two different paths was sending out the RST, reducing an information side-channel.

rscheff: When a host receives a TCP packet to a port which is not listening, or no connection exists, or…
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Gotcha, thanks. Would "This value also uses ECN for RST replies to probes of non-open ports." mean the same? It looks clearer to me.

pauamma_gundo.com: Gotcha, thanks. Would "This value also uses ECN for RST replies to probes of non-open ports."…
are non-zero, a new key will be automatically generated after this specified are non-zero, a new key will be automatically generated after this specified
seconds. seconds.
The default is 120. The default is 120.
.It Va fastopen.ccache_bucket_limit .It Va fastopen.ccache_bucket_limit
The maximum number of entries in a client cookie cache bucket. The maximum number of entries in a client cookie cache bucket.
The default value can be tuned with the The default value can be tuned with the
.Dv TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT .Dv TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT
kernel option or by setting kernel option or by setting
▲ Show 20 Lines • Show All 201 Lines • ▼ Show 20 Lines
The value of 1 limits the logging to The value of 1 limits the logging to
.Tn SYN .Tn SYN
(connection establishment) packets only. (connection establishment) packets only.
A value of 2 results in any A value of 2 results in any
.Tn TCP .Tn TCP
packets to closed ports being logged. packets to closed ports being logged.
Any value not listed above disables the logging Any value not listed above disables the logging
(default is 0, i.e., the logging is disabled). (default is 0, i.e., the logging is disabled).
.It Va maxtcptw .It Va maxtcptw
When a TCP connection enters the When a TCP connection enters the
.Dv TIME_WAIT .Dv TIME_WAIT
state, its associated socket structure is freed, since it is of state, its associated socket structure is freed, since it is of
negligible size and use, and a new structure is allocated to contain a negligible size and use, and a new structure is allocated to contain a
minimal amount of information necessary for sustaining a connection in minimal amount of information necessary for sustaining a connection in
this state, called the compressed TCP this state, called the compressed TCP
.Dv TIME_WAIT .Dv TIME_WAIT
state. state.
Since this structure is smaller than a socket structure, it can save Since this structure is smaller than a socket structure, it can save
a significant amount of system memory. a significant amount of system memory.
The The
.Va net.inet.tcp.maxtcptw .Va net.inet.tcp.maxtcptw
MIB variable controls the maximum number of these structures allocated. MIB variable controls the maximum number of these structures allocated.
By default, it is initialized to By default, it is initialized to
.Va kern.ipc.maxsockets .Va kern.ipc.maxsockets
/ 5. / 5.
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Was removing this intended as part of this review?

pauamma_gundo.com: Was removing this intended as part of this review?
rscheffAuthorUnsubmitted
Done
Inline Actions

I'm confused, there is no change here on reviews.freebsd.org; it may be that this diff was uploaded just prior to a flurry of tcp related (including man page) changes, which I have not yet rebased the patch to...

rscheff: I'm confused, there is no change here on reviews.freebsd.org; it may be that this diff was…
.It Va minmss .It Va minmss
Minimum TCP Maximum Segment Size; used to prevent a denial of service attack Minimum TCP Maximum Segment Size; used to prevent a denial of service attack
from an unreasonably low MSS. from an unreasonably low MSS.
.It Va msl .It Va msl
The Maximum Segment Lifetime, in milliseconds, for a packet. The Maximum Segment Lifetime, in milliseconds, for a packet.
.It Va mssdflt .It Va mssdflt
The default value used for the TCP Maximum Segment Size The default value used for the TCP Maximum Segment Size
.Pq Dq MSS .Pq Dq MSS
▲ Show 20 Lines • Show All 337 Lines • Show Last 20 Lines
View Options

head/lib/libc++experimental/Makefile

Show All 28 Lines
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE. .\" SUCH DAMAGE.
.\" .\"
.\" From: @(#)tcp.4 8.1 (Berkeley) 6/5/93 .\" From: @(#)tcp.4 8.1 (Berkeley) 6/5/93
.\" $FreeBSD$ .\" $FreeBSD$
.\" .\"
.Dd October 7, 2022 .Dd October 13, 2022
.Dt TCP 4 .Dt TCP 4
.Os .Os
.Sh NAME .Sh NAME
.Nm tcp .Nm tcp
.Nd Internet Transmission Control Protocol .Nd Internet Transmission Control Protocol
.Sh SYNOPSIS .Sh SYNOPSIS
.In sys/types.h .In sys/types.h
.In sys/socket.h .In sys/socket.h
▲ Show 20 Lines • Show All 459 Lines • ▼ Show 20 Lines
Outgoing connections will request ECN. Outgoing connections will request ECN.
.It 2 .It 2
Allow incoming connections to request ECN. Allow incoming connections to request ECN.
Outgoing connections will not request ECN. Outgoing connections will not request ECN.
(default) (default)
.It 3 .It 3
Negotiate on incoming connection for Accurate ECN, ECN, or no ECN. Negotiate on incoming connection for Accurate ECN, ECN, or no ECN.
Outgoing connections will request Accurate ECN and fall back to Outgoing connections will request Accurate ECN and fall back to
ECN depending on the capabilities of the server. ECN depending on the capabilities of the remote host.
pauamma_gundo.comUnsubmitted
Done
Inline Actions
Outgoing connections will request Accurate ECN and fall back to
- ECN depending on the capabilities of the server.
+ ECN depending on the capabilities of the remote host.
.It 4
pauamma_gundo.com:
.It 4 .It 4
Negotiate on incoming connection for Accurate ECN, ECN, or no ECN. Negotiate on incoming connection for Accurate ECN, ECN, or no ECN.
Outgoing connections will not request ECN. Outgoing connections will not request ECN.
.El
.It Va ecn.generalized
Enable sending all segments as ECN capable transport,
including SYN, SYN/ACK, and retransmissions.
This may only be enabled when ECN support itself is also active.
Disabling ECN support will disable this feature automatically.
Settings:
.Bl -tag -compact
.It 0
Regular RFC3168 operation.
Send only new data segments as ECN capable transport.
(default)
.It 1
Support generalized ECN (ECN++), and send all segments of an ECN-enabled
session as ECN capable transport.
Also control packets to non-established and non-listening ports are
identically marked, if outgoing sessions would request ECN.
.El .El
.It Va ecn.maxretries .It Va ecn.maxretries
Number of retries (SYN or SYN/ACK retransmits) before disabling ECN on a Number of retries (SYN or SYN/ACK retransmits) before disabling ECN on a
specific connection. specific connection.
This is needed to help with connection establishment This is needed to help with connection establishment
when a broken firewall is in the network path. when a broken firewall is in the network path.
.It Va fast_finwait2_recycle .It Va fast_finwait2_recycle
Recycle Recycle
.Tn TCP .Tn TCP
.Dv FIN_WAIT_2 .Dv FIN_WAIT_2
pauamma_gundo.comUnsubmitted
Done
Inline Actions
including SYN, SYN/ACK, and retransmissions.
- This may only be enabled, when ECN support itself is also active.
+ This may only be enabled when ECN support itself is also active.
Disabling ECN support will disable this feature automatically.
pauamma_gundo.com:
connections faster when the socket is marked as connections faster when the socket is marked as
.Dv SBS_CANTRCVMORE .Dv SBS_CANTRCVMORE
(no user process has the socket open, data received on (no user process has the socket open, data received on
the socket cannot be read). the socket cannot be read).
The timeout used here is The timeout used here is
.Va finwait2_timeout . .Va finwait2_timeout .
.It Va fastopen.acceptany .It Va fastopen.acceptany
pauamma_gundo.comUnsubmitted
Done
Inline Actions
Regular RFC3168 operation.
- Send only new data segements as ECN capable transport.
- (default)
+ Send only new data segments as ECN capable transport (default).
.It 1

Typo and move full stop to a more natural place.

pauamma_gundo.com: Typo and move full stop to a more natural place.
When non-zero, all client-supplied TFO cookies will be considered to be valid. When non-zero, all client-supplied TFO cookies will be considered to be valid.
The default is 0. The default is 0.
.It Va fastopen.autokey .It Va fastopen.autokey
When this and When this and
.Va net.inet.tcp.fastopen.server_enable .Va net.inet.tcp.fastopen.server_enable
bcrUnsubmitted
Done
Inline Actions

s/identially/identically/

bcr: s/identially/identically/
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Can you explain what you mean by that? I'm arguably not the indended audience, but if I don't understand it, there's a chance some of the intended audience and or some interested readers won't either.

pauamma_gundo.com: Can you explain what you mean by that? I'm arguably not the indended audience, but if I don't…
rscheffAuthorUnsubmitted
Done
Inline Actions

When a host receives a TCP packet to a port which is not listening, or no connection exists, or the header information is in some other way not acceptable, the host may respond with a RST (reset) packet. Some of these RST packets are sent from "regular" TCP processing (e.g. outside the sequence window) and others from non-open ports. Making these distinctable by carrying different markings - depending which code path was sending them - would give clues as to what ports/services may be reachable, and give rise to more targetted attacks.
As part if this change, when introducing this new capability (modified TCP header markings for sessions), the irregular codepath is addressed too, such that a 3rd party can not deduct which of the two different paths was sending out the RST, reducing an information side-channel.

rscheff: When a host receives a TCP packet to a port which is not listening, or no connection exists, or…
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Gotcha, thanks. Would "This value also uses ECN for RST replies to probes of non-open ports." mean the same? It looks clearer to me.

pauamma_gundo.com: Gotcha, thanks. Would "This value also uses ECN for RST replies to probes of non-open ports."…
are non-zero, a new key will be automatically generated after this specified are non-zero, a new key will be automatically generated after this specified
seconds. seconds.
The default is 120. The default is 120.
.It Va fastopen.ccache_bucket_limit .It Va fastopen.ccache_bucket_limit
The maximum number of entries in a client cookie cache bucket. The maximum number of entries in a client cookie cache bucket.
The default value can be tuned with the The default value can be tuned with the
.Dv TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT .Dv TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT
kernel option or by setting kernel option or by setting
▲ Show 20 Lines • Show All 201 Lines • ▼ Show 20 Lines
The value of 1 limits the logging to The value of 1 limits the logging to
.Tn SYN .Tn SYN
(connection establishment) packets only. (connection establishment) packets only.
A value of 2 results in any A value of 2 results in any
.Tn TCP .Tn TCP
packets to closed ports being logged. packets to closed ports being logged.
Any value not listed above disables the logging Any value not listed above disables the logging
(default is 0, i.e., the logging is disabled). (default is 0, i.e., the logging is disabled).
.It Va maxtcptw .It Va maxtcptw
When a TCP connection enters the When a TCP connection enters the
.Dv TIME_WAIT .Dv TIME_WAIT
state, its associated socket structure is freed, since it is of state, its associated socket structure is freed, since it is of
negligible size and use, and a new structure is allocated to contain a negligible size and use, and a new structure is allocated to contain a
minimal amount of information necessary for sustaining a connection in minimal amount of information necessary for sustaining a connection in
this state, called the compressed TCP this state, called the compressed TCP
.Dv TIME_WAIT .Dv TIME_WAIT
state. state.
Since this structure is smaller than a socket structure, it can save Since this structure is smaller than a socket structure, it can save
a significant amount of system memory. a significant amount of system memory.
The The
.Va net.inet.tcp.maxtcptw .Va net.inet.tcp.maxtcptw
MIB variable controls the maximum number of these structures allocated. MIB variable controls the maximum number of these structures allocated.
By default, it is initialized to By default, it is initialized to
.Va kern.ipc.maxsockets .Va kern.ipc.maxsockets
/ 5. / 5.
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Was removing this intended as part of this review?

pauamma_gundo.com: Was removing this intended as part of this review?
rscheffAuthorUnsubmitted
Done
Inline Actions

I'm confused, there is no change here on reviews.freebsd.org; it may be that this diff was uploaded just prior to a flurry of tcp related (including man page) changes, which I have not yet rebased the patch to...

rscheff: I'm confused, there is no change here on reviews.freebsd.org; it may be that this diff was…
.It Va minmss .It Va minmss
Minimum TCP Maximum Segment Size; used to prevent a denial of service attack Minimum TCP Maximum Segment Size; used to prevent a denial of service attack
from an unreasonably low MSS. from an unreasonably low MSS.
.It Va msl .It Va msl
The Maximum Segment Lifetime, in milliseconds, for a packet. The Maximum Segment Lifetime, in milliseconds, for a packet.
.It Va mssdflt .It Va mssdflt
The default value used for the TCP Maximum Segment Size The default value used for the TCP Maximum Segment Size
.Pq Dq MSS .Pq Dq MSS
▲ Show 20 Lines • Show All 337 Lines • Show Last 20 Lines
View Options

head/tools/build/mk/OptionalObsoleteFiles.inc

Show All 28 Lines
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE. .\" SUCH DAMAGE.
.\" .\"
.\" From: @(#)tcp.4 8.1 (Berkeley) 6/5/93 .\" From: @(#)tcp.4 8.1 (Berkeley) 6/5/93
.\" $FreeBSD$ .\" $FreeBSD$
.\" .\"
.Dd October 7, 2022 .Dd October 13, 2022
.Dt TCP 4 .Dt TCP 4
.Os .Os
.Sh NAME .Sh NAME
.Nm tcp .Nm tcp
.Nd Internet Transmission Control Protocol .Nd Internet Transmission Control Protocol
.Sh SYNOPSIS .Sh SYNOPSIS
.In sys/types.h .In sys/types.h
.In sys/socket.h .In sys/socket.h
▲ Show 20 Lines • Show All 459 Lines • ▼ Show 20 Lines
Outgoing connections will request ECN. Outgoing connections will request ECN.
.It 2 .It 2
Allow incoming connections to request ECN. Allow incoming connections to request ECN.
Outgoing connections will not request ECN. Outgoing connections will not request ECN.
(default) (default)
.It 3 .It 3
Negotiate on incoming connection for Accurate ECN, ECN, or no ECN. Negotiate on incoming connection for Accurate ECN, ECN, or no ECN.
Outgoing connections will request Accurate ECN and fall back to Outgoing connections will request Accurate ECN and fall back to
ECN depending on the capabilities of the server. ECN depending on the capabilities of the remote host.
pauamma_gundo.comUnsubmitted
Done
Inline Actions
Outgoing connections will request Accurate ECN and fall back to
- ECN depending on the capabilities of the server.
+ ECN depending on the capabilities of the remote host.
.It 4
pauamma_gundo.com:
.It 4 .It 4
Negotiate on incoming connection for Accurate ECN, ECN, or no ECN. Negotiate on incoming connection for Accurate ECN, ECN, or no ECN.
Outgoing connections will not request ECN. Outgoing connections will not request ECN.
.El
.It Va ecn.generalized
Enable sending all segments as ECN capable transport,
including SYN, SYN/ACK, and retransmissions.
This may only be enabled when ECN support itself is also active.
Disabling ECN support will disable this feature automatically.
Settings:
.Bl -tag -compact
.It 0
Regular RFC3168 operation.
Send only new data segments as ECN capable transport.
(default)
.It 1
Support generalized ECN (ECN++), and send all segments of an ECN-enabled
session as ECN capable transport.
Also control packets to non-established and non-listening ports are
identically marked, if outgoing sessions would request ECN.
.El .El
.It Va ecn.maxretries .It Va ecn.maxretries
Number of retries (SYN or SYN/ACK retransmits) before disabling ECN on a Number of retries (SYN or SYN/ACK retransmits) before disabling ECN on a
specific connection. specific connection.
This is needed to help with connection establishment This is needed to help with connection establishment
when a broken firewall is in the network path. when a broken firewall is in the network path.
.It Va fast_finwait2_recycle .It Va fast_finwait2_recycle
Recycle Recycle
.Tn TCP .Tn TCP
.Dv FIN_WAIT_2 .Dv FIN_WAIT_2
pauamma_gundo.comUnsubmitted
Done
Inline Actions
including SYN, SYN/ACK, and retransmissions.
- This may only be enabled, when ECN support itself is also active.
+ This may only be enabled when ECN support itself is also active.
Disabling ECN support will disable this feature automatically.
pauamma_gundo.com:
connections faster when the socket is marked as connections faster when the socket is marked as
.Dv SBS_CANTRCVMORE .Dv SBS_CANTRCVMORE
(no user process has the socket open, data received on (no user process has the socket open, data received on
the socket cannot be read). the socket cannot be read).
The timeout used here is The timeout used here is
.Va finwait2_timeout . .Va finwait2_timeout .
.It Va fastopen.acceptany .It Va fastopen.acceptany
pauamma_gundo.comUnsubmitted
Done
Inline Actions
Regular RFC3168 operation.
- Send only new data segements as ECN capable transport.
- (default)
+ Send only new data segments as ECN capable transport (default).
.It 1

Typo and move full stop to a more natural place.

pauamma_gundo.com: Typo and move full stop to a more natural place.
When non-zero, all client-supplied TFO cookies will be considered to be valid. When non-zero, all client-supplied TFO cookies will be considered to be valid.
The default is 0. The default is 0.
.It Va fastopen.autokey .It Va fastopen.autokey
When this and When this and
.Va net.inet.tcp.fastopen.server_enable .Va net.inet.tcp.fastopen.server_enable
bcrUnsubmitted
Done
Inline Actions

s/identially/identically/

bcr: s/identially/identically/
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Can you explain what you mean by that? I'm arguably not the indended audience, but if I don't understand it, there's a chance some of the intended audience and or some interested readers won't either.

pauamma_gundo.com: Can you explain what you mean by that? I'm arguably not the indended audience, but if I don't…
rscheffAuthorUnsubmitted
Done
Inline Actions

When a host receives a TCP packet to a port which is not listening, or no connection exists, or the header information is in some other way not acceptable, the host may respond with a RST (reset) packet. Some of these RST packets are sent from "regular" TCP processing (e.g. outside the sequence window) and others from non-open ports. Making these distinctable by carrying different markings - depending which code path was sending them - would give clues as to what ports/services may be reachable, and give rise to more targetted attacks.
As part if this change, when introducing this new capability (modified TCP header markings for sessions), the irregular codepath is addressed too, such that a 3rd party can not deduct which of the two different paths was sending out the RST, reducing an information side-channel.

rscheff: When a host receives a TCP packet to a port which is not listening, or no connection exists, or…
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Gotcha, thanks. Would "This value also uses ECN for RST replies to probes of non-open ports." mean the same? It looks clearer to me.

pauamma_gundo.com: Gotcha, thanks. Would "This value also uses ECN for RST replies to probes of non-open ports."…
are non-zero, a new key will be automatically generated after this specified are non-zero, a new key will be automatically generated after this specified
seconds. seconds.
The default is 120. The default is 120.
.It Va fastopen.ccache_bucket_limit .It Va fastopen.ccache_bucket_limit
The maximum number of entries in a client cookie cache bucket. The maximum number of entries in a client cookie cache bucket.
The default value can be tuned with the The default value can be tuned with the
.Dv TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT .Dv TCP_FASTOPEN_CCACHE_BUCKET_LIMIT_DEFAULT
kernel option or by setting kernel option or by setting
▲ Show 20 Lines • Show All 201 Lines • ▼ Show 20 Lines
The value of 1 limits the logging to The value of 1 limits the logging to
.Tn SYN .Tn SYN
(connection establishment) packets only. (connection establishment) packets only.
A value of 2 results in any A value of 2 results in any
.Tn TCP .Tn TCP
packets to closed ports being logged. packets to closed ports being logged.
Any value not listed above disables the logging Any value not listed above disables the logging
(default is 0, i.e., the logging is disabled). (default is 0, i.e., the logging is disabled).
.It Va maxtcptw .It Va maxtcptw
When a TCP connection enters the When a TCP connection enters the
.Dv TIME_WAIT .Dv TIME_WAIT
state, its associated socket structure is freed, since it is of state, its associated socket structure is freed, since it is of
negligible size and use, and a new structure is allocated to contain a negligible size and use, and a new structure is allocated to contain a
minimal amount of information necessary for sustaining a connection in minimal amount of information necessary for sustaining a connection in
this state, called the compressed TCP this state, called the compressed TCP
.Dv TIME_WAIT .Dv TIME_WAIT
state. state.
Since this structure is smaller than a socket structure, it can save Since this structure is smaller than a socket structure, it can save
a significant amount of system memory. a significant amount of system memory.
The The
.Va net.inet.tcp.maxtcptw .Va net.inet.tcp.maxtcptw
MIB variable controls the maximum number of these structures allocated. MIB variable controls the maximum number of these structures allocated.
By default, it is initialized to By default, it is initialized to
.Va kern.ipc.maxsockets .Va kern.ipc.maxsockets
/ 5. / 5.
pauamma_gundo.comUnsubmitted
Done
Inline Actions

Was removing this intended as part of this review?

pauamma_gundo.com: Was removing this intended as part of this review?
rscheffAuthorUnsubmitted
Done
Inline Actions

I'm confused, there is no change here on reviews.freebsd.org; it may be that this diff was uploaded just prior to a flurry of tcp related (including man page) changes, which I have not yet rebased the patch to...

rscheff: I'm confused, there is no change here on reviews.freebsd.org; it may be that this diff was…
.It Va minmss .It Va minmss
Minimum TCP Maximum Segment Size; used to prevent a denial of service attack Minimum TCP Maximum Segment Size; used to prevent a denial of service attack
from an unreasonably low MSS. from an unreasonably low MSS.
.It Va msl .It Va msl
The Maximum Segment Lifetime, in milliseconds, for a packet. The Maximum Segment Lifetime, in milliseconds, for a packet.
.It Va mssdflt .It Va mssdflt
The default value used for the TCP Maximum Segment Size The default value used for the TCP Maximum Segment Size
.Pq Dq MSS .Pq Dq MSS
▲ Show 20 Lines • Show All 337 Lines • Show Last 20 Lines