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Compiled tree of Oasis Linux based on own branch at <https://hacktivis.me/git/oasis/> git clone https://anongit.hacktivis.me/git/oasis-root.git

ip-tcp_metrics.8 (3470B)

    

  1. .TH "IP\-TCP_METRICS" 8 "23 Aug 2012" "iproute2" "Linux"
  2. .SH "NAME"
  3. ip-tcp_metrics \- management for TCP Metrics
  4. .SH "SYNOPSIS"
  5. .sp
  6. .ad l
  7. .in +8
  8. .ti -8
  9. .B ip
  10. .RI "[ " OPTIONS " ]"
  11. .B tcp_metrics
  12. .RI "{ " COMMAND " | "
  13. .BR help " }"
  14. .sp
  16. .ti -8
  17. .BR "ip tcp_metrics" " { " show " | " flush " }
  18. .IR SELECTOR
  20. .ti -8
  21. .BR "ip tcp_metrics delete " [ " address " ]
  22. .IR ADDRESS
  24. .ti -8
  25. .IR SELECTOR " := "
  26. .RB "[ [ " address " ] "
  27. .IR PREFIX " ]"
  29. .SH "DESCRIPTION"
  30. .B ip tcp_metrics
  31. is used to manipulate entries in the kernel that keep TCP information
  32. for IPv4 and IPv6 destinations. The entries are created when
  33. TCP sockets want to share information for destinations and are
  34. stored in a cache keyed by the destination address. The saved
  35. information may include values for metrics (initially obtained from
  36. routes), recent TSVAL for TIME-WAIT recycling purposes, state for the
  37. Fast Open feature, etc.
  38. For performance reasons the cache can not grow above configured limit
  39. and the older entries are replaced with fresh information, sometimes
  40. reclaimed and used for new destinations. The kernel never removes
  41. entries, they can be flushed only with this tool.
  43. .SS ip tcp_metrics show - show cached entries
  45. .TP
  46. .BI address " PREFIX " (default)
  47. IPv4/IPv6 prefix or address. If no prefix is provided all entries are shown.
  49. .LP
  50. The output may contain the following information:
  52. .BI age " <S.MMM>" sec
  53. - time after the entry was created, reset or updated with metrics
  54. from sockets. The entry is reset and refreshed on use with metrics from
  55. route if the metrics are not updated in last hour. Not all cached values
  56. reset the age on update.
  58. .BI cwnd " <N>"
  59. - CWND metric value
  61. .BI fo_cookie " <HEX-STRING>"
  62. - Cookie value received in SYN-ACK to be used by Fast Open for next SYNs
  64. .BI fo_mss " <N>"
  65. - MSS value received in SYN-ACK to be used by Fast Open for next SYNs
  67. .BI fo_syn_drops " <N>/<S.MMM>" "sec ago"
  68. - Number of drops of initial outgoing Fast Open SYNs with data
  69. detected by monitoring the received SYN-ACK after SYN retransmission.
  70. The seconds show the time after last SYN drop and together with
  71. the drop count can be used to disable Fast Open for some time.
  73. .BI reordering " <N>"
  74. - Reordering metric value
  76. .BI rtt " <N>" us
  77. - RTT metric value
  79. .BI rttvar " <N>" us
  80. - RTTVAR metric value
  82. .BI ssthresh " <SSTHRESH>"
  83. - SSTHRESH metric value
  85. .BI tw_ts " <TSVAL>/<SEC>" "sec ago"
  86. - recent TSVAL and the seconds after saving it into TIME-WAIT socket
  88. .SS ip tcp_metrics delete - delete single entry
  90. .TP
  91. .BI address " ADDRESS " (default)
  92. IPv4/IPv6 address. The address is a required argument.
  94. .SS ip tcp_metrics flush - flush entries
  95. This command flushes the entries selected by some criteria.
  97. .PP
  98. This command has the same arguments as
  99. .B show.
  101. .SH "EXAMPLES"
  102. .PP
  103. ip tcp_metrics show address 192.168.0.0/24
  104. .RS 4
  105. Shows the entries for destinations from subnet
  106. .RE
  107. .PP
  108. ip tcp_metrics show 192.168.0.0/24
  109. .RS 4
  110. The same but address keyword is optional
  111. .RE
  112. .PP
  113. ip tcp_metrics
  114. .RS 4
  115. Show all is the default action
  116. .RE
  117. .PP
  118. ip tcp_metrics delete 192.168.0.1
  119. .RS 4
  120. Removes the entry for 192.168.0.1 from cache.
  121. .RE
  122. .PP
  123. ip tcp_metrics flush 192.168.0.0/24
  124. .RS 4
  125. Removes entries for destinations from subnet
  126. .RE
  127. .PP
  128. ip tcp_metrics flush all
  129. .RS 4
  130. Removes all entries from cache
  131. .RE
  132. .PP
  133. ip -6 tcp_metrics flush all
  134. .RS 4
  135. Removes all IPv6 entries from cache keeping the IPv4 entries.
  136. .RE
  138. .SH SEE ALSO
  139. .br
  140. .BR ip (8)
  142. .SH AUTHOR
  143. Original Manpage by Julian Anastasov <ja@ssi.bg>