* [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options @ 2021-09-24 23:54 Wei Wang 2021-10-15 16:08 ` Wei Wang 0 siblings, 1 reply; 6+ messages in thread From: Wei Wang @ 2021-09-24 23:54 UTC (permalink / raw) To: Alejandro Colomar, Michael Kerrisk, linux-man Cc: netdev, Yuchung Cheng, Neal Cardwell, Eric Dumazet TCP_FASTOPEN socket option was added by: commit 8336886f786fdacbc19b719c1f7ea91eb70706d4 TCP_FASTOPEN_CONNECT socket option was added by the following patch series: commit 065263f40f0972d5f1cd294bb0242bd5aa5f06b2 commit 25776aa943401662617437841b3d3ea4693ee98a commit 19f6d3f3c8422d65b5e3d2162e30ef07c6e21ea2 commit 3979ad7e82dfe3fb94a51c3915e64ec64afa45c3 Add detailed description for these 2 options. Also add descriptions for /proc entry tcp_fastopen and tcp_fastopen_key. Signed-off-by: Wei Wang <weiwan@google.com> --- man7/tcp.7 | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) diff --git a/man7/tcp.7 b/man7/tcp.7 index 0a7c61a37..bdd4a33ca 100644 --- a/man7/tcp.7 +++ b/man7/tcp.7 @@ -423,6 +423,28 @@ option. .\" Since 2.4.0-test7 Enable RFC\ 2883 TCP Duplicate SACK support. .TP +.IR tcp_fastopen " (Bitmask; default: 0x1; since Linux 3.7)" +Enables RFC\ 7413 Fast Open support. +The flag is used as a bitmap with the following values: +.RS +.IP 0x1 +Enables client side Fast Open support +.IP 0x2 +Enables server side Fast Open support +.IP 0x4 +Allows client side to transmit data in SYN without Fast Open option +.IP 0x200 +Allows server side to accept SYN data without Fast Open option +.IP 0x400 +Enables Fast Open on all listeners without +.B TCP_FASTOPEN +socket option +.RE +.TP +.IR tcp_fastopen_key " (since Linux 3.7)" +Set server side RFC\ 7413 Fast Open key to generate Fast Open cookie +when server side Fast Open support is enabled. +.TP .IR tcp_ecn " (Integer; default: see below; since Linux 2.4)" .\" Since 2.4.0-test7 Enable RFC\ 3168 Explicit Congestion Notification. @@ -1202,6 +1224,109 @@ Bound the size of the advertised window to this value. The kernel imposes a minimum size of SOCK_MIN_RCVBUF/2. This option should not be used in code intended to be portable. +.TP +.BR TCP_FASTOPEN " (since Linux 3.6)" +This option enables Fast Open (RFC\ 7413) on the listener socket. +The value specifies the maximum length of pending SYNs +(similar to the backlog argument in +.BR listen (2)). +Once enabled, +the listener socket grants the TCP Fast Open cookie on incoming +SYN with TCP Fast Open option. +.IP +More importantly it accepts the data in SYN with a valid Fast Open cookie +and responds SYN-ACK acknowledging both the data and the SYN sequence. +.BR accept (2) +returns a socket that is available for read and write when the handshake +has not completed yet. +Thus the data exchange can commence before the handshake completes. +This option requires enabling the server-side support on sysctl +.IR net.ipv4.tcp_fastopen +(see above). +For TCP Fast Open client-side support, +see +.BR send (2) +.B MSG_FASTOPEN +or +.B TCP_FASTOPEN_CONNECT +below. +.TP +.BR TCP_FASTOPEN_CONNECT " (since Linux 4.11)" +This option enables an alternative way to perform Fast Open on the active +side (client). +When this option is enabled, +.BR connect (2) +would behave differently depending on if a Fast Open cookie is available +for the destination. +.IP +If a cookie is not available (i.e. first contact to the destination), +.BR connect (2) +behaves as usual by sending a SYN immediately, +except the SYN would include an empty Fast Open cookie option to solicit a +cookie. +.IP +If a cookie is available, +.BR connect (2) +would return 0 immediately but the SYN transmission is defered. +A subsequent +.BR write (2) +or +.BR sendmsg (2) +would trigger a SYN with data plus cookie in the Fast Open option. +In other words, +the actual connect operation is deferred until data is supplied. +.IP +.B Note: +While this option is designed for convenience, +enabling it does change the behaviors and certain system calls might set +different +.I errno +values. +With cookie present, +.BR write (2) +or +.BR sendmsg (2) +must be called right after +.BR connect (2) +in order to send out SYN+data to complete 3WHS and establish connection. +Calling +.BR read (2) +right after +.BR connect (2) +without +.BR write (2) +will cause the blocking socket to be blocked forever. +.IP +The application should either set +.B TCP_FASTOPEN_CONNECT +socket option before +.BR write (2) +or +.BR sendmsg (2) +, +or call +.BR write (2) +or +.BR sendmsg (2) +with +.B MSG_FASTOPEN +flag directly, +instead of both on the same connection. +.IP +Here is the typical call flow with this new option: +.IP +.in +4n +.EX +s = socket(); +setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, 1, ...); +connect(s); +write(s); // write() should always follow connect() in order to trigger SYN to go out +read(s)/write(s); +... +close(s); +.EE +.in +.IP .SS Sockets API TCP provides limited support for out-of-band data, in the form of (a single byte of) urgent data. -- 2.33.0.685.g46640cef36-goog ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options 2021-09-24 23:54 [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options Wei Wang @ 2021-10-15 16:08 ` Wei Wang 2021-10-15 22:12 ` Alejandro Colomar (man-pages) 0 siblings, 1 reply; 6+ messages in thread From: Wei Wang @ 2021-10-15 16:08 UTC (permalink / raw) To: Alejandro Colomar, Michael Kerrisk, linux-man Cc: netdev, Yuchung Cheng, Neal Cardwell, Eric Dumazet On Fri, Sep 24, 2021 at 4:54 PM Wei Wang <weiwan@google.com> wrote: > > TCP_FASTOPEN socket option was added by: > commit 8336886f786fdacbc19b719c1f7ea91eb70706d4 > TCP_FASTOPEN_CONNECT socket option was added by the following patch > series: > commit 065263f40f0972d5f1cd294bb0242bd5aa5f06b2 > commit 25776aa943401662617437841b3d3ea4693ee98a > commit 19f6d3f3c8422d65b5e3d2162e30ef07c6e21ea2 > commit 3979ad7e82dfe3fb94a51c3915e64ec64afa45c3 > Add detailed description for these 2 options. > Also add descriptions for /proc entry tcp_fastopen and tcp_fastopen_key. > > Signed-off-by: Wei Wang <weiwan@google.com> > --- Hi Alex, Does this version look OK to you to apply? Let me know. Thanks. Wei > man7/tcp.7 | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 125 insertions(+) > > diff --git a/man7/tcp.7 b/man7/tcp.7 > index 0a7c61a37..bdd4a33ca 100644 > --- a/man7/tcp.7 > +++ b/man7/tcp.7 > @@ -423,6 +423,28 @@ option. > .\" Since 2.4.0-test7 > Enable RFC\ 2883 TCP Duplicate SACK support. > .TP > +.IR tcp_fastopen " (Bitmask; default: 0x1; since Linux 3.7)" > +Enables RFC\ 7413 Fast Open support. > +The flag is used as a bitmap with the following values: > +.RS > +.IP 0x1 > +Enables client side Fast Open support > +.IP 0x2 > +Enables server side Fast Open support > +.IP 0x4 > +Allows client side to transmit data in SYN without Fast Open option > +.IP 0x200 > +Allows server side to accept SYN data without Fast Open option > +.IP 0x400 > +Enables Fast Open on all listeners without > +.B TCP_FASTOPEN > +socket option > +.RE > +.TP > +.IR tcp_fastopen_key " (since Linux 3.7)" > +Set server side RFC\ 7413 Fast Open key to generate Fast Open cookie > +when server side Fast Open support is enabled. > +.TP > .IR tcp_ecn " (Integer; default: see below; since Linux 2.4)" > .\" Since 2.4.0-test7 > Enable RFC\ 3168 Explicit Congestion Notification. > @@ -1202,6 +1224,109 @@ Bound the size of the advertised window to this value. > The kernel imposes a minimum size of SOCK_MIN_RCVBUF/2. > This option should not be used in code intended to be > portable. > +.TP > +.BR TCP_FASTOPEN " (since Linux 3.6)" > +This option enables Fast Open (RFC\ 7413) on the listener socket. > +The value specifies the maximum length of pending SYNs > +(similar to the backlog argument in > +.BR listen (2)). > +Once enabled, > +the listener socket grants the TCP Fast Open cookie on incoming > +SYN with TCP Fast Open option. > +.IP > +More importantly it accepts the data in SYN with a valid Fast Open cookie > +and responds SYN-ACK acknowledging both the data and the SYN sequence. > +.BR accept (2) > +returns a socket that is available for read and write when the handshake > +has not completed yet. > +Thus the data exchange can commence before the handshake completes. > +This option requires enabling the server-side support on sysctl > +.IR net.ipv4.tcp_fastopen > +(see above). > +For TCP Fast Open client-side support, > +see > +.BR send (2) > +.B MSG_FASTOPEN > +or > +.B TCP_FASTOPEN_CONNECT > +below. > +.TP > +.BR TCP_FASTOPEN_CONNECT " (since Linux 4.11)" > +This option enables an alternative way to perform Fast Open on the active > +side (client). > +When this option is enabled, > +.BR connect (2) > +would behave differently depending on if a Fast Open cookie is available > +for the destination. > +.IP > +If a cookie is not available (i.e. first contact to the destination), > +.BR connect (2) > +behaves as usual by sending a SYN immediately, > +except the SYN would include an empty Fast Open cookie option to solicit a > +cookie. > +.IP > +If a cookie is available, > +.BR connect (2) > +would return 0 immediately but the SYN transmission is defered. > +A subsequent > +.BR write (2) > +or > +.BR sendmsg (2) > +would trigger a SYN with data plus cookie in the Fast Open option. > +In other words, > +the actual connect operation is deferred until data is supplied. > +.IP > +.B Note: > +While this option is designed for convenience, > +enabling it does change the behaviors and certain system calls might set > +different > +.I errno > +values. > +With cookie present, > +.BR write (2) > +or > +.BR sendmsg (2) > +must be called right after > +.BR connect (2) > +in order to send out SYN+data to complete 3WHS and establish connection. > +Calling > +.BR read (2) > +right after > +.BR connect (2) > +without > +.BR write (2) > +will cause the blocking socket to be blocked forever. > +.IP > +The application should either set > +.B TCP_FASTOPEN_CONNECT > +socket option before > +.BR write (2) > +or > +.BR sendmsg (2) > +, > +or call > +.BR write (2) > +or > +.BR sendmsg (2) > +with > +.B MSG_FASTOPEN > +flag directly, > +instead of both on the same connection. > +.IP > +Here is the typical call flow with this new option: > +.IP > +.in +4n > +.EX > +s = socket(); > +setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, 1, ...); > +connect(s); > +write(s); // write() should always follow connect() in order to trigger SYN to go out > +read(s)/write(s); > +... > +close(s); > +.EE > +.in > +.IP > .SS Sockets API > TCP provides limited support for out-of-band data, > in the form of (a single byte of) urgent data. > -- > 2.33.0.685.g46640cef36-goog > ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options 2021-10-15 16:08 ` Wei Wang @ 2021-10-15 22:12 ` Alejandro Colomar (man-pages) 2021-11-05 17:19 ` Wei Wang 0 siblings, 1 reply; 6+ messages in thread From: Alejandro Colomar (man-pages) @ 2021-10-15 22:12 UTC (permalink / raw) To: Wei Wang, Michael Kerrisk, linux-man Cc: netdev, Yuchung Cheng, Neal Cardwell, Eric Dumazet Hi Wei, On 10/15/21 6:08 PM, Wei Wang wrote: > On Fri, Sep 24, 2021 at 4:54 PM Wei Wang <weiwan@google.com> wrote: >> >> TCP_FASTOPEN socket option was added by: >> commit 8336886f786fdacbc19b719c1f7ea91eb70706d4 >> TCP_FASTOPEN_CONNECT socket option was added by the following patch >> series: >> commit 065263f40f0972d5f1cd294bb0242bd5aa5f06b2 >> commit 25776aa943401662617437841b3d3ea4693ee98a >> commit 19f6d3f3c8422d65b5e3d2162e30ef07c6e21ea2 >> commit 3979ad7e82dfe3fb94a51c3915e64ec64afa45c3 >> Add detailed description for these 2 options. >> Also add descriptions for /proc entry tcp_fastopen and tcp_fastopen_key. >> >> Signed-off-by: Wei Wang <weiwan@google.com> >> --- > > Hi Alex, > > Does this version look OK to you to apply? > Let me know. Sorry, I missed that patch. Thanks for the ping! I'll try to have a look at it ASAP. Thanks, Alex > > Thanks. > Wei -- Alejandro Colomar Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es/ ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options 2021-10-15 22:12 ` Alejandro Colomar (man-pages) @ 2021-11-05 17:19 ` Wei Wang 2021-11-12 20:55 ` Alejandro Colomar (man-pages) 0 siblings, 1 reply; 6+ messages in thread From: Wei Wang @ 2021-11-05 17:19 UTC (permalink / raw) To: Alejandro Colomar (man-pages) Cc: Michael Kerrisk, linux-man, netdev, Yuchung Cheng, Neal Cardwell, Eric Dumazet On Fri, Oct 15, 2021 at 3:12 PM Alejandro Colomar (man-pages) <alx.manpages@gmail.com> wrote: > > Hi Wei, > > On 10/15/21 6:08 PM, Wei Wang wrote: > > On Fri, Sep 24, 2021 at 4:54 PM Wei Wang <weiwan@google.com> wrote: > >> > >> TCP_FASTOPEN socket option was added by: > >> commit 8336886f786fdacbc19b719c1f7ea91eb70706d4 > >> TCP_FASTOPEN_CONNECT socket option was added by the following patch > >> series: > >> commit 065263f40f0972d5f1cd294bb0242bd5aa5f06b2 > >> commit 25776aa943401662617437841b3d3ea4693ee98a > >> commit 19f6d3f3c8422d65b5e3d2162e30ef07c6e21ea2 > >> commit 3979ad7e82dfe3fb94a51c3915e64ec64afa45c3 > >> Add detailed description for these 2 options. > >> Also add descriptions for /proc entry tcp_fastopen and tcp_fastopen_key. > >> > >> Signed-off-by: Wei Wang <weiwan@google.com> > >> --- > > > > Hi Alex, > > > > Does this version look OK to you to apply? > > Let me know. > > Sorry, I missed that patch. > Thanks for the ping! I'll try to have a look at it ASAP. > Hi Alex, I am not sure if this patch has been applied yet? If not, could you help take a look? Let me know if you'd like me to resend it. Thanks. Wei > Thanks, > > Alex > > > > > > Thanks. > > Wei > > > -- > Alejandro Colomar > Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ > http://www.alejandro-colomar.es/ ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options 2021-11-05 17:19 ` Wei Wang @ 2021-11-12 20:55 ` Alejandro Colomar (man-pages) 2021-11-12 20:58 ` Wei Wang 0 siblings, 1 reply; 6+ messages in thread From: Alejandro Colomar (man-pages) @ 2021-11-12 20:55 UTC (permalink / raw) To: Wei Wang Cc: Michael Kerrisk, linux-man, netdev, Yuchung Cheng, Neal Cardwell, Eric Dumazet, G. Branden Robinson Hi Wei, On 11/5/21 18:19, Wei Wang wrote: > On Fri, Oct 15, 2021 at 3:12 PM Alejandro Colomar (man-pages) > <alx.manpages@gmail.com> wrote: >> >> Hi Wei, >> >> On 10/15/21 6:08 PM, Wei Wang wrote: >>> On Fri, Sep 24, 2021 at 4:54 PM Wei Wang <weiwan@google.com> wrote: >>>> >>>> TCP_FASTOPEN socket option was added by: >>>> commit 8336886f786fdacbc19b719c1f7ea91eb70706d4 >>>> TCP_FASTOPEN_CONNECT socket option was added by the following patch >>>> series: >>>> commit 065263f40f0972d5f1cd294bb0242bd5aa5f06b2 >>>> commit 25776aa943401662617437841b3d3ea4693ee98a >>>> commit 19f6d3f3c8422d65b5e3d2162e30ef07c6e21ea2 >>>> commit 3979ad7e82dfe3fb94a51c3915e64ec64afa45c3 >>>> Add detailed description for these 2 options. >>>> Also add descriptions for /proc entry tcp_fastopen and tcp_fastopen_key. >>>> >>>> Signed-off-by: Wei Wang <weiwan@google.com> Sorry for the delay. I have applied it now. I also applied some minor changes on top of your patch (see below). Thanks! Alex --- tcp.7: Minor tweaks to Wei's patch - wsfix - Boldface literals (see groff_man(7)). - Replace '\ ' by \~, per Branden's advise. - Use phrasal semantic newlines. - Put '...' in a C comment, to avoid interfering with groff. It has the side effect that the code example is pure C now. - Remove incorrect trailing '.IP'. Cc: Wei Wang <weiwan@google.com> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com> diff --git a/man7/tcp.7 b/man7/tcp.7 index 264e3ccc4..69d85c05a 100644 --- a/man7/tcp.7 +++ b/man7/tcp.7 @@ -423,26 +423,31 @@ option. .\" Since 2.4.0-test7 Enable RFC\ 2883 TCP Duplicate SACK support. .TP -.IR tcp_fastopen " (Bitmask; default: 0x1; since Linux 3.7)" -Enables RFC\ 7413 Fast Open support. +.IR tcp_fastopen " (Bitmask; default: 0x1; since Linux 3.7)" +Enables RFC\~7413 Fast Open support. The flag is used as a bitmap with the following values: .RS -.IP 0x1 +.TP +.B 0x1 Enables client side Fast Open support -.IP 0x2 +.TP +.B 0x2 Enables server side Fast Open support -.IP 0x4 +.TP +.B 0x4 Allows client side to transmit data in SYN without Fast Open option -.IP 0x200 +.TP +.B 0x200 Allows server side to accept SYN data without Fast Open option -.IP 0x400 +.TP +.B 0x400 Enables Fast Open on all listeners without .B TCP_FASTOPEN socket option .RE .TP .IR tcp_fastopen_key " (since Linux 3.7)" -Set server side RFC\ 7413 Fast Open key to generate Fast Open cookie +Set server side RFC\~7413 Fast Open key to generate Fast Open cookie when server side Fast Open support is enabled. .TP .IR tcp_ecn " (Integer; default: see below; since Linux 2.4)" @@ -1226,19 +1231,19 @@ This option should not be used in code intended to be portable. .TP .BR TCP_FASTOPEN " (since Linux 3.6)" -This option enables Fast Open (RFC\ 7413) on the listener socket. +This option enables Fast Open (RFC\~7413) on the listener socket. The value specifies the maximum length of pending SYNs (similar to the backlog argument in .BR listen (2)). Once enabled, -the listener socket grants the TCP Fast Open cookie on incoming -SYN with TCP Fast Open option. +the listener socket grants the TCP Fast Open cookie +on incoming SYN with TCP Fast Open option. .IP More importantly it accepts the data in SYN with a valid Fast Open cookie and responds SYN-ACK acknowledging both the data and the SYN sequence. .BR accept (2) -returns a socket that is available for read and write when the handshake -has not completed yet. +returns a socket that is available for read and write +when the handshake has not completed yet. Thus the data exchange can commence before the handshake completes. This option requires enabling the server-side support on sysctl .IR net.ipv4.tcp_fastopen @@ -1252,18 +1257,18 @@ or below. .TP .BR TCP_FASTOPEN_CONNECT " (since Linux 4.11)" -This option enables an alternative way to perform Fast Open on the active -side (client). +This option enables an alternative way to perform Fast Open +on the active side (client). When this option is enabled, .BR connect (2) -would behave differently depending on if a Fast Open cookie is available -for the destination. +would behave differently depending on +if a Fast Open cookie is available for the destination. .IP If a cookie is not available (i.e. first contact to the destination), .BR connect (2) behaves as usual by sending a SYN immediately, -except the SYN would include an empty Fast Open cookie option to solicit a -cookie. +except the SYN would include an empty Fast Open cookie option +to solicit a cookie. .IP If a cookie is available, .BR connect (2) @@ -1297,13 +1302,12 @@ without .BR write (2) will cause the blocking socket to be blocked forever. .IP -The application should either set +The application should either set .B TCP_FASTOPEN_CONNECT socket option before .BR write (2) or -.BR sendmsg (2) -, +.BR sendmsg (2), or call .BR write (2) or @@ -1322,11 +1326,10 @@ setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, 1, ...); connect(s); write(s); // write() should always follow connect() in order to trigger SYN to go out read(s)/write(s); -... +/* ... */ close(s); .EE .in -.IP .SS Sockets API TCP provides limited support for out-of-band data, in the form of (a single byte of) urgent data. ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options 2021-11-12 20:55 ` Alejandro Colomar (man-pages) @ 2021-11-12 20:58 ` Wei Wang 0 siblings, 0 replies; 6+ messages in thread From: Wei Wang @ 2021-11-12 20:58 UTC (permalink / raw) To: Alejandro Colomar (man-pages) Cc: Michael Kerrisk, linux-man, netdev, Yuchung Cheng, Neal Cardwell, Eric Dumazet, G. Branden Robinson On Fri, Nov 12, 2021 at 12:56 PM Alejandro Colomar (man-pages) <alx.manpages@gmail.com> wrote: > > Hi Wei, > > On 11/5/21 18:19, Wei Wang wrote: > > On Fri, Oct 15, 2021 at 3:12 PM Alejandro Colomar (man-pages) > > <alx.manpages@gmail.com> wrote: > >> > >> Hi Wei, > >> > >> On 10/15/21 6:08 PM, Wei Wang wrote: > >>> On Fri, Sep 24, 2021 at 4:54 PM Wei Wang <weiwan@google.com> wrote: > >>>> > >>>> TCP_FASTOPEN socket option was added by: > >>>> commit 8336886f786fdacbc19b719c1f7ea91eb70706d4 > >>>> TCP_FASTOPEN_CONNECT socket option was added by the following patch > >>>> series: > >>>> commit 065263f40f0972d5f1cd294bb0242bd5aa5f06b2 > >>>> commit 25776aa943401662617437841b3d3ea4693ee98a > >>>> commit 19f6d3f3c8422d65b5e3d2162e30ef07c6e21ea2 > >>>> commit 3979ad7e82dfe3fb94a51c3915e64ec64afa45c3 > >>>> Add detailed description for these 2 options. > >>>> Also add descriptions for /proc entry tcp_fastopen and tcp_fastopen_key. > >>>> > >>>> Signed-off-by: Wei Wang <weiwan@google.com> > > Sorry for the delay. > I have applied it now. > I also applied some minor changes on top of your patch > (see below). > Thank you so much for the fixes and thanks for applying, Alex! > Thanks! > Alex > > > --- > > tcp.7: Minor tweaks to Wei's patch > > - wsfix > - Boldface literals (see groff_man(7)). > - Replace '\ ' by \~, per Branden's advise. > - Use phrasal semantic newlines. > - Put '...' in a C comment, to avoid interfering with groff. > It has the side effect that the code example is pure C now. > - Remove incorrect trailing '.IP'. > > Cc: Wei Wang <weiwan@google.com> > Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com> > > diff --git a/man7/tcp.7 b/man7/tcp.7 > index 264e3ccc4..69d85c05a 100644 > --- a/man7/tcp.7 > +++ b/man7/tcp.7 > @@ -423,26 +423,31 @@ option. > .\" Since 2.4.0-test7 > Enable RFC\ 2883 TCP Duplicate SACK support. > .TP > -.IR tcp_fastopen " (Bitmask; default: 0x1; since Linux 3.7)" > -Enables RFC\ 7413 Fast Open support. > +.IR tcp_fastopen " (Bitmask; default: 0x1; since Linux 3.7)" > +Enables RFC\~7413 Fast Open support. > The flag is used as a bitmap with the following values: > .RS > -.IP 0x1 > +.TP > +.B 0x1 > Enables client side Fast Open support > -.IP 0x2 > +.TP > +.B 0x2 > Enables server side Fast Open support > -.IP 0x4 > +.TP > +.B 0x4 > Allows client side to transmit data in SYN without Fast Open option > -.IP 0x200 > +.TP > +.B 0x200 > Allows server side to accept SYN data without Fast Open option > -.IP 0x400 > +.TP > +.B 0x400 > Enables Fast Open on all listeners without > .B TCP_FASTOPEN > socket option > .RE > .TP > .IR tcp_fastopen_key " (since Linux 3.7)" > -Set server side RFC\ 7413 Fast Open key to generate Fast Open cookie > +Set server side RFC\~7413 Fast Open key to generate Fast Open cookie > when server side Fast Open support is enabled. > .TP > .IR tcp_ecn " (Integer; default: see below; since Linux 2.4)" > @@ -1226,19 +1231,19 @@ This option should not be used in code intended > to be > portable. > .TP > .BR TCP_FASTOPEN " (since Linux 3.6)" > -This option enables Fast Open (RFC\ 7413) on the listener socket. > +This option enables Fast Open (RFC\~7413) on the listener socket. > The value specifies the maximum length of pending SYNs > (similar to the backlog argument in > .BR listen (2)). > Once enabled, > -the listener socket grants the TCP Fast Open cookie on incoming > -SYN with TCP Fast Open option. > +the listener socket grants the TCP Fast Open cookie > +on incoming SYN with TCP Fast Open option. > .IP > More importantly it accepts the data in SYN with a valid Fast Open cookie > and responds SYN-ACK acknowledging both the data and the SYN sequence. > .BR accept (2) > -returns a socket that is available for read and write when the handshake > -has not completed yet. > +returns a socket that is available for read and write > +when the handshake has not completed yet. > Thus the data exchange can commence before the handshake completes. > This option requires enabling the server-side support on sysctl > .IR net.ipv4.tcp_fastopen > @@ -1252,18 +1257,18 @@ or > below. > .TP > .BR TCP_FASTOPEN_CONNECT " (since Linux 4.11)" > -This option enables an alternative way to perform Fast Open on the active > -side (client). > +This option enables an alternative way to perform Fast Open > +on the active side (client). > When this option is enabled, > .BR connect (2) > -would behave differently depending on if a Fast Open cookie is available > -for the destination. > +would behave differently depending on > +if a Fast Open cookie is available for the destination. > .IP > If a cookie is not available (i.e. first contact to the destination), > .BR connect (2) > behaves as usual by sending a SYN immediately, > -except the SYN would include an empty Fast Open cookie option to solicit a > -cookie. > +except the SYN would include an empty Fast Open cookie option > +to solicit a cookie. > .IP > If a cookie is available, > .BR connect (2) > @@ -1297,13 +1302,12 @@ without > .BR write (2) > will cause the blocking socket to be blocked forever. > .IP > -The application should either set > +The application should either set > .B TCP_FASTOPEN_CONNECT > socket option before > .BR write (2) > or > -.BR sendmsg (2) > -, > +.BR sendmsg (2), > or call > .BR write (2) > or > @@ -1322,11 +1326,10 @@ setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT, > 1, ...); > connect(s); > write(s); // write() should always follow connect() in order to > trigger SYN to go out > read(s)/write(s); > -... > +/* ... */ > close(s); > .EE > .in > -.IP > .SS Sockets API > TCP provides limited support for out-of-band data, > in the form of (a single byte of) urgent data. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-11-12 20:59 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2021-09-24 23:54 [patch v3] tcp.7: Add description for TCP_FASTOPEN and TCP_FASTOPEN_CONNECT options Wei Wang 2021-10-15 16:08 ` Wei Wang 2021-10-15 22:12 ` Alejandro Colomar (man-pages) 2021-11-05 17:19 ` Wei Wang 2021-11-12 20:55 ` Alejandro Colomar (man-pages) 2021-11-12 20:58 ` Wei Wang
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