From 6f80235904def10dd4752a8c53544cecf36e2a79 Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Mon, 20 Jun 2005 14:45:09 +0000 Subject: [PATCH] More tcp_stdurg and SIOCATMARK work --- man7/tcp.7 | 38 ++++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 16 deletions(-) diff --git a/man7/tcp.7 b/man7/tcp.7 index 06b5e7f57..58dc921a4 100644 --- a/man7/tcp.7 +++ b/man7/tcp.7 @@ -198,7 +198,7 @@ A maximum of (window/2^tcp_app_win, mss) bytes in the window are reserved for the application buffer. A value of 0 implies that no amount is reserved. .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_bic " (Boolean; default: disabled)" Enable BIC TCP congestion control algorithm. @@ -211,14 +211,14 @@ increment ensures linear RTT fairness as well as good scalability. Under small congestion windows, binary search increase provides TCP friendliness. .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_bic_low_window " (integer; default: 14)" Sets the threshold window (in packets) where BIC TCP starts to adjust the congestion window. Below this threshold BIC TCP behaves the same as the default TCP Reno. .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_bic_fast_convergence " (Boolean; default: enabled)" Forces BIC TCP to more quickly respond to changes in congestion @@ -244,7 +244,7 @@ the TCP specification, but required to prevent denial-of-service attacks. In Linux 2.2, the default value was 180. .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_frto " (Boolean; default: disabled)" Enables F-RTO, an enhanced recovery algorithm for TCP retransmission @@ -273,7 +273,7 @@ of 75 seconds apart) when keep-alive is enabled. Note that underlying connection tracking mechanisms and application timeouts may be much shorter. .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_low_latency " (Boolean; default: disabled)" If enabled, the TCP stack makes decisions that prefer lower @@ -425,13 +425,18 @@ in low-memory systems. Enable RFC2018 TCP Selective Acknowledgements. .TP .BR tcp_stdurg " (Boolean; default: disabled)" -Use the strict RFC793 interpretation of the TCP -urgent-pointer field. If this option is disabled, then use the -BSD-compatible interpretation of the urgent-pointer, pointing -to the first byte after the urgent data. The RFC793 -interpretation is to have it point to the last byte of urgent -data. Enabling this option may lead to interoperability -problems. +If this option is enabled, then use the "strict" RFC793 interpretation +of the TCP urgent-pointer field. +(RFC793 was ambiguous in its specification of the meaning of the +urgent pointer. +Here, the "strict" interpretation means the +one imposed by RFC961 and RFC1122.) +According to this interpretation, the urgent pointer points +to the last byte of urgent data. +If this option is disabled, then use the BSD-compatible interpretation of +the urgent-pointer: +the urgent pointer points to the first byte after the urgent data. +Enabling this option may lead to interoperability problems. .TP .BR tcp_synack_retries " (integer; default: 5)" The maximum number of times a SYN/ACK segment @@ -470,7 +475,7 @@ Enabling this option is not recommended since this causes problems when working with NAT (Network Address Translation). .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_tw_reuse " (Boolean; default: disabled)" Allow to reuse TIME-WAIT sockets for new connections when it is @@ -491,7 +496,7 @@ employed. If is disabled, TCP will not negotiate the use of window scaling with the other end during connection setup. .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_vegas_cong_avoid " (Boolean; default: disabled)" Enable TCP Vegas congestion avoidance algorithm. @@ -501,7 +506,7 @@ adjusts the sending rate by modifying the congestion window. TCP Vegas should provide less packet loss, but it is not as aggressive as TCP Reno. .\" -.\" The following is from 2.6.12: Doumentation/networking/ip-sysctl.txt +.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt .TP .BR tcp_westwood " (Boolean; default: disabled)" Enable TCP Westwood+ congestion control algorithm. @@ -711,7 +716,8 @@ the urgent data (to actually read the urgent data requires the flag). .sp Note that a read never reads across the urgent mark. -A program can thus advance up to the mark by performing reads +Thus, having obtained notification of the presence of urgent data, +a program can advance up to the mark by performing reads (requesting any number of bytes) and testing .B SIOCATMARK after each read.