diff options
Diffstat (limited to 'Documentation/networking/ip-sysctl.txt')
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 66 |
1 files changed, 58 insertions, 8 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 725b8bea58a7..df33674799b5 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -80,6 +80,7 @@ fib_multipath_hash_policy - INTEGER Possible values: 0 - Layer 3 1 - Layer 4 + 2 - Layer 3 or inner Layer 3 if present fib_sync_mem - UNSIGNED INTEGER Amount of dirty memory from fib entries that can be backlogged before @@ -255,6 +256,14 @@ tcp_base_mss - INTEGER Path MTU discovery (MTU probing). If MTU probing is enabled, this is the initial MSS used by the connection. +tcp_min_snd_mss - INTEGER + TCP SYN and SYNACK messages usually advertise an ADVMSS option, + as described in RFC 1122 and RFC 6691. + If this ADVMSS option is smaller than tcp_min_snd_mss, + it is silently capped to tcp_min_snd_mss. + + Default : 48 (at least 8 bytes of payload per segment) + tcp_congestion_control - STRING Set the congestion control algorithm to be used for new connections. The algorithm "reno" is always available, but @@ -560,10 +569,10 @@ tcp_comp_sack_delay_ns - LONG INTEGER Default : 1,000,000 ns (1 ms) tcp_comp_sack_nr - INTEGER - Max numer of SACK that can be compressed. + Max number of SACK that can be compressed. Using 0 disables SACK compression. - Detault : 44 + Default : 44 tcp_slow_start_after_idle - BOOLEAN If set, provide RFC2861 behavior and time out the congestion @@ -648,6 +657,26 @@ tcp_fastopen_blackhole_timeout_sec - INTEGER 0 to disable the blackhole detection. By default, it is set to 1hr. +tcp_fastopen_key - list of comma separated 32-digit hexadecimal INTEGERs + The list consists of a primary key and an optional backup key. The + primary key is used for both creating and validating cookies, while the + optional backup key is only used for validating cookies. The purpose of + the backup key is to maximize TFO validation when keys are rotated. + + A randomly chosen primary key may be configured by the kernel if + the tcp_fastopen sysctl is set to 0x400 (see above), or if the + TCP_FASTOPEN setsockopt() optname is set and a key has not been + previously configured via sysctl. If keys are configured via + setsockopt() by using the TCP_FASTOPEN_KEY optname, then those + per-socket keys will be used instead of any keys that are specified via + sysctl. + + A key is specified as 4 8-digit hexadecimal integers which are separated + by a '-' as: xxxxxxxx-xxxxxxxx-xxxxxxxx-xxxxxxxx. Leading zeros may be + omitted. A primary and a backup key may be specified by separating them + by a comma. If only one key is specified, it becomes the primary key and + any previously configured backup keys are removed. + tcp_syn_retries - INTEGER Number of times initial SYNs for an active TCP connection attempt will be retransmitted. Should not be higher than 127. Default value @@ -772,6 +801,14 @@ tcp_challenge_ack_limit - INTEGER in RFC 5961 (Improving TCP's Robustness to Blind In-Window Attacks) Default: 100 +tcp_rx_skb_cache - BOOLEAN + Controls a per TCP socket cache of one skb, that might help + performance of some workloads. This might be dangerous + on systems with a lot of TCP sockets, since it increases + memory usage. + + Default: 0 (disabled) + UDP variables: udp_l3mdev_accept - BOOLEAN @@ -1409,14 +1446,26 @@ flowlabel_state_ranges - BOOLEAN FALSE: disabled Default: true -flowlabel_reflect - BOOLEAN - Automatically reflect the flow label. Needed for Path MTU +flowlabel_reflect - INTEGER + Control flow label reflection. Needed for Path MTU Discovery to work with Equal Cost Multipath Routing in anycast environments. See RFC 7690 and: https://tools.ietf.org/html/draft-wang-6man-flow-label-reflection-01 - TRUE: enabled - FALSE: disabled - Default: FALSE + + This is a bitmask. + 1: enabled for established flows + + Note that this prevents automatic flowlabel changes, as done + in "tcp: change IPv6 flow-label upon receiving spurious retransmission" + and "tcp: Change txhash on every SYN and RTO retransmit" + + 2: enabled for TCP RESET packets (no active listener) + If set, a RST packet sent in response to a SYN packet on a closed + port will reflect the incoming flow label. + + 4: enabled for ICMPv6 echo reply messages. + + Default: 0 fib_multipath_hash_policy - INTEGER Controls which hash policy to use for multipath routes. @@ -1424,6 +1473,7 @@ fib_multipath_hash_policy - INTEGER Possible values: 0 - Layer 3 (source and destination addresses plus flow label) 1 - Layer 4 (standard 5-tuple) + 2 - Layer 3 or inner Layer 3 if present anycast_src_echo_reply - BOOLEAN Controls the use of anycast addresses as source addresses for ICMPv6 @@ -2237,7 +2287,7 @@ addr_scope_policy - INTEGER /proc/sys/net/core/* - Please see: Documentation/sysctl/net.txt for descriptions of these entries. + Please see: Documentation/admin-guide/sysctl/net.rst for descriptions of these entries. /proc/sys/net/unix/* |