2a6de301ee
According to RFC 5681 (3.2) the TCP Fast Retransmit algorithm should start if the threshold of 3 duplicate ACKs is reached. Thus the threshold should be a constant, not an integer option.
215 lines
6.5 KiB
Plaintext
215 lines
6.5 KiB
Plaintext
#
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# For a description of the syntax of this configuration file,
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# see the file kconfig-language.txt in the NuttX tools repository.
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#
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menu "TCP/IP Networking"
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config NET_TCP
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bool "TCP/IP Networking"
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default n
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select NET_READAHEAD if !NET_TCP_NO_STACK
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---help---
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Enable or disable TCP networking support.
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config NET_TCP_NO_STACK
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bool "Disable TCP/IP Stack"
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default n
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select NET_TCP
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---help---
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Build without TCP/IP stack even if TCP networking support enabled.
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if NET_TCP && !NET_TCP_NO_STACK
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config NET_TCP_DELAYED_ACK
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bool "TCP/IP Delayed ACK"
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default n
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---help---
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RFC 1122: A host that is receiving a stream of TCP data segments
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can increase efficiency in both the Internet and the hosts
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by sending fewer than one ACK (acknowledgment) segment per data
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segment received; this is known as a "delayed ACK".
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TCP should implement a delayed ACK, but an ACK should not be
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excessively delayed; in particular, the delay MUST be less than
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0.5 seconds, and in a stream of full-sized segments there should
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be an ACK for at least every second segments.
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config NET_TCP_KEEPALIVE
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bool "TCP/IP Keep-alive support"
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default n
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select NET_TCPPROTO_OPTIONS
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---help---
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Enable support for the SO_KEEPALIVE socket option
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config NET_TCPURGDATA
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bool "Urgent data"
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default n
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---help---
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Determines if support for TCP urgent data notification should be
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compiled in. Urgent data (out-of-band data) is a rarely used TCP feature
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that is very seldom would be required.
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config NET_TCP_CONNS
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int "Number of TCP/IP connections"
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default 8
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---help---
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Maximum number of TCP/IP connections (all tasks)
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config NET_TCP_NPOLLWAITERS
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int "Number of TCP poll waiters"
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default 1
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config NET_TCP_RTO
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int "RTO of TCP/IP connections"
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default 3
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---help---
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RTO of TCP/IP connections (all tasks)
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config NET_TCP_WAIT_TIMEOUT
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int "TIME_WAIT Length of TCP/IP connections"
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default 120
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---help---
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TIME_WAIT Length of TCP/IP connections (all tasks). In units
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of seconds.
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config NET_MAX_LISTENPORTS
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int "Number of listening ports"
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default 20
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---help---
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Maximum number of listening TCP/IP ports (all tasks). Default: 20
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config NET_TCP_FAST_RETRANSMIT
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bool "Enable the Fast Retransmit algorithm"
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default y
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---help---
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RFC2001:
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3. Fast Retransmit
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Modifications to the congestion avoidance algorithm were proposed in
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1990 [3]. Before describing the change, realize that TCP may
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generate an immediate acknowledgment (a duplicate ACK) when an out-
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of-order segment is received (Section 4.2.2.21 of [1], with a note
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that one reason for doing so was for the experimental fast-
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retransmit algorithm). This duplicate ACK should not be delayed.
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The purpose of this duplicate ACK is to let the other end know that a
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segment was received out of order, and to tell it what sequence
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number is expected.
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Since TCP does not know whether a duplicate ACK is caused by a lost
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segment or just a reordering of segments, it waits for a small number
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of duplicate ACKs to be received. It is assumed that if there is
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just a reordering of the segments, there will be only one or two
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duplicate ACKs before the reordered segment is processed, which will
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then generate a new ACK. If three or more duplicate ACKs are
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received in a row, it is a strong indication that a segment has been
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lost. TCP then performs a retransmission of what appears to be the
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missing segment, without waiting for a retransmission timer to
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expire.
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config NET_TCP_WINDOW_SCALE
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bool "Enable TCP/IP Window Scale Option"
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default n
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---help---
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RFC1323:
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2. TCP WINDOW SCALE OPTION
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The window scale extension expands the definition of the TCP
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window to 32 bits and then uses a scale factor to carry this 32-
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bit value in the 16-bit Window field of the TCP header (SEG.WND in
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RFC-793).
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if NET_TCP_WINDOW_SCALE
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config NET_TCP_WINDOW_SCALE_FACTOR
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int "TCP/IP Window Scale Factor"
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default 0
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---help---
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This is the default value for window scale factor.
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endif # NET_TCP_WINDOW_SCALE
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config NET_TCP_NOTIFIER
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bool "Support TCP notifications"
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default n
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depends on SCHED_WORKQUEUE
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select WQUEUE_NOTIFIER
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---help---
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Enable building of TCP notifier logic that will execute a worker
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function on the low priority work queue when read-ahead data
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is available or when a TCP connection is lost. This is is a general
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purpose notifier, but was developed specifically to support poll()
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logic where the poll must wait for these events.
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config NET_TCP_WRITE_BUFFERS
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bool "Enable TCP/IP write buffering"
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default n
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select NET_WRITE_BUFFERS
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---help---
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Write buffers allows buffering of ongoing TCP/IP packets, providing
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for higher performance, streamed output.
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You might want to disable TCP/IP write buffering on a highly memory
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memory constrained system where there are no performance issues.
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if NET_TCP_WRITE_BUFFERS
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config NET_TCP_NWRBCHAINS
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int "Number of pre-allocated I/O buffer chain heads"
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default 8
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---help---
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These tiny nodes are used as "containers" to support queuing of
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TCP write buffers. This setting will limit the number of TCP write
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operations that can be "in-flight" at any give time. So a good
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choice for this value would be the same as the maximum number of
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TCP connections.
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config NET_TCP_WRBUFFER_DEBUG
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bool "Force write buffer debug"
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default n
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depends on DEBUG_FEATURES
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select IOB_DEBUG
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---help---
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This option will force debug output from TCP write buffer logic,
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even without network debug output. This is not normally something
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that would want to do but is convenient if you are debugging the
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write buffer logic and do not want to get overloaded with other
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network-related debug output.
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config NET_TCP_WRBUFFER_DUMP
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bool "Force write buffer dump"
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default n
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depends on DEBUG_NET || NET_TCP_WRBUFFER_DEBUG
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select IOB_DEBUG
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---help---
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Dump the contents of the write buffers. You do not want to do this
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unless you really want to analyze the write buffer transfers in
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detail.
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endif # NET_TCP_WRITE_BUFFERS
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config NET_TCPBACKLOG
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bool "TCP/IP backlog support"
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default n
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---help---
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Incoming connections pend in a backlog until accept() is called.
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The size of the backlog is selected when listen() is called.
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if NET_TCPBACKLOG
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config NET_TCPBACKLOG_CONNS
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int "TCP backlog conns threshold"
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default 8
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---help---
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Maximum number of TCP backlog connections (all tasks).
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endif # NET_TCPBACKLOG
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config NET_SENDFILE
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bool "Optimized network sendfile()"
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default n
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---help---
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Support larger, higher performance sendfile() for transferring
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files out a TCP connection.
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endif # NET_TCP && !NET_TCP_NO_STACK
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endmenu # TCP/IP Networking
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