1 ================================ 1 ================================
2 Documentation for /proc/sys/net/ 2 Documentation for /proc/sys/net/
3 ================================ 3 ================================
4 4
5 Copyright 5 Copyright
6 6
7 Copyright (c) 1999 7 Copyright (c) 1999
8 8
9 - Terrehon Bowden <terrehon@pacbell.net 9 - Terrehon Bowden <terrehon@pacbell.net>
10 - Bodo Bauer <bb@ricochet.net> 10 - Bodo Bauer <bb@ricochet.net>
11 11
12 Copyright (c) 2000 12 Copyright (c) 2000
13 13
14 - Jorge Nerin <comandante@zaralinux.com 14 - Jorge Nerin <comandante@zaralinux.com>
15 15
16 Copyright (c) 2009 16 Copyright (c) 2009
17 17
18 - Shen Feng <shen@cn.fujitsu.com> 18 - Shen Feng <shen@cn.fujitsu.com>
19 19
20 For general info and legal blurb, please look 20 For general info and legal blurb, please look in index.rst.
21 21
22 ---------------------------------------------- 22 ------------------------------------------------------------------------------
23 23
24 This file contains the documentation for the s 24 This file contains the documentation for the sysctl files in
25 /proc/sys/net 25 /proc/sys/net
26 26
27 The interface to the networking parts of 27 The interface to the networking parts of the kernel is located in
28 /proc/sys/net. The following table shows all p 28 /proc/sys/net. The following table shows all possible subdirectories. You may
29 see only some of them, depending on your kerne 29 see only some of them, depending on your kernel's configuration.
30 30
31 31
32 Table : Subdirectories in /proc/sys/net 32 Table : Subdirectories in /proc/sys/net
33 33
34 ========= =================== = ========== == !! 34 ========= =================== = ========== ==================
35 Directory Content Directory Co 35 Directory Content Directory Content
36 ========= =================== = ========== == !! 36 ========= =================== = ========== ==================
37 802 E802 protocol mptcp Mu !! 37 core General parameter appletalk Appletalk protocol
38 appletalk Appletalk protocol netfilter Ne !! 38 unix Unix domain sockets netrom NET/ROM
39 ax25 AX25 netrom NE !! 39 802 E802 protocol ax25 AX25
40 bridge Bridging rose X. !! 40 ethernet Ethernet protocol rose X.25 PLP layer
41 core General parameter tipc TI <<
42 ethernet Ethernet protocol unix Un <<
43 ipv4 IP version 4 x25 X. 41 ipv4 IP version 4 x25 X.25 protocol
44 ipv6 IP version 6 !! 42 bridge Bridging decnet DEC net
45 ========= =================== = ========== == !! 43 ipv6 IP version 6 tipc TIPC
>> 44 ========= =================== = ========== ==================
46 45
47 1. /proc/sys/net/core - Network core options 46 1. /proc/sys/net/core - Network core options
48 ============================================ 47 ============================================
49 48
50 bpf_jit_enable 49 bpf_jit_enable
51 -------------- 50 --------------
52 51
53 This enables the BPF Just in Time (JIT) compil 52 This enables the BPF Just in Time (JIT) compiler. BPF is a flexible
54 and efficient infrastructure allowing to execu 53 and efficient infrastructure allowing to execute bytecode at various
55 hook points. It is used in a number of Linux k 54 hook points. It is used in a number of Linux kernel subsystems such
56 as networking (e.g. XDP, tc), tracing (e.g. kp 55 as networking (e.g. XDP, tc), tracing (e.g. kprobes, uprobes, tracepoints)
57 and security (e.g. seccomp). LLVM has a BPF ba 56 and security (e.g. seccomp). LLVM has a BPF back end that can compile
58 restricted C into a sequence of BPF instructio 57 restricted C into a sequence of BPF instructions. After program load
59 through bpf(2) and passing a verifier in the k 58 through bpf(2) and passing a verifier in the kernel, a JIT will then
60 translate these BPF proglets into native CPU i 59 translate these BPF proglets into native CPU instructions. There are
61 two flavors of JITs, the newer eBPF JIT curren 60 two flavors of JITs, the newer eBPF JIT currently supported on:
62 61
63 - x86_64 62 - x86_64
64 - x86_32 63 - x86_32
65 - arm64 64 - arm64
66 - arm32 65 - arm32
67 - ppc64 66 - ppc64
68 - ppc32 <<
69 - sparc64 67 - sparc64
70 - mips64 68 - mips64
71 - s390x 69 - s390x
72 - riscv64 !! 70 - riscv
73 - riscv32 <<
74 - loongarch64 <<
75 - arc <<
76 71
77 And the older cBPF JIT supported on the follow 72 And the older cBPF JIT supported on the following archs:
78 73
79 - mips 74 - mips
>> 75 - ppc
80 - sparc 76 - sparc
81 77
82 eBPF JITs are a superset of cBPF JITs, meaning 78 eBPF JITs are a superset of cBPF JITs, meaning the kernel will
83 migrate cBPF instructions into eBPF instructio 79 migrate cBPF instructions into eBPF instructions and then JIT
84 compile them transparently. Older cBPF JITs ca 80 compile them transparently. Older cBPF JITs can only translate
85 tcpdump filters, seccomp rules, etc, but not m 81 tcpdump filters, seccomp rules, etc, but not mentioned eBPF
86 programs loaded through bpf(2). 82 programs loaded through bpf(2).
87 83
88 Values: 84 Values:
89 85
90 - 0 - disable the JIT (default value) 86 - 0 - disable the JIT (default value)
91 - 1 - enable the JIT 87 - 1 - enable the JIT
92 - 2 - enable the JIT and ask the compi 88 - 2 - enable the JIT and ask the compiler to emit traces on kernel log.
93 89
94 bpf_jit_harden 90 bpf_jit_harden
95 -------------- 91 --------------
96 92
97 This enables hardening for the BPF JIT compile 93 This enables hardening for the BPF JIT compiler. Supported are eBPF
98 JIT backends. Enabling hardening trades off pe 94 JIT backends. Enabling hardening trades off performance, but can
99 mitigate JIT spraying. 95 mitigate JIT spraying.
100 96
101 Values: 97 Values:
102 98
103 - 0 - disable JIT hardening (default v 99 - 0 - disable JIT hardening (default value)
104 - 1 - enable JIT hardening for unprivi 100 - 1 - enable JIT hardening for unprivileged users only
105 - 2 - enable JIT hardening for all use 101 - 2 - enable JIT hardening for all users
106 102
107 where "privileged user" in this context means <<
108 CAP_BPF or CAP_SYS_ADMIN in the root user name <<
109 <<
110 bpf_jit_kallsyms 103 bpf_jit_kallsyms
111 ---------------- 104 ----------------
112 105
113 When BPF JIT compiler is enabled, then compile 106 When BPF JIT compiler is enabled, then compiled images are unknown
114 addresses to the kernel, meaning they neither 107 addresses to the kernel, meaning they neither show up in traces nor
115 in /proc/kallsyms. This enables export of thes 108 in /proc/kallsyms. This enables export of these addresses, which can
116 be used for debugging/tracing. If bpf_jit_hard 109 be used for debugging/tracing. If bpf_jit_harden is enabled, this
117 feature is disabled. 110 feature is disabled.
118 111
119 Values : 112 Values :
120 113
121 - 0 - disable JIT kallsyms export (def 114 - 0 - disable JIT kallsyms export (default value)
122 - 1 - enable JIT kallsyms export for p 115 - 1 - enable JIT kallsyms export for privileged users only
123 116
124 bpf_jit_limit 117 bpf_jit_limit
125 ------------- 118 -------------
126 119
127 This enforces a global limit for memory alloca 120 This enforces a global limit for memory allocations to the BPF JIT
128 compiler in order to reject unprivileged JIT r 121 compiler in order to reject unprivileged JIT requests once it has
129 been surpassed. bpf_jit_limit contains the val 122 been surpassed. bpf_jit_limit contains the value of the global limit
130 in bytes. 123 in bytes.
131 124
132 dev_weight 125 dev_weight
133 ---------- 126 ----------
134 127
135 The maximum number of packets that kernel can 128 The maximum number of packets that kernel can handle on a NAPI interrupt,
136 it's a Per-CPU variable. For drivers that supp 129 it's a Per-CPU variable. For drivers that support LRO or GRO_HW, a hardware
137 aggregated packet is counted as one packet in 130 aggregated packet is counted as one packet in this context.
138 131
139 Default: 64 132 Default: 64
140 133
141 dev_weight_rx_bias 134 dev_weight_rx_bias
142 ------------------ 135 ------------------
143 136
144 RPS (e.g. RFS, aRFS) processing is competing w 137 RPS (e.g. RFS, aRFS) processing is competing with the registered NAPI poll function
145 of the driver for the per softirq cycle netdev 138 of the driver for the per softirq cycle netdev_budget. This parameter influences
146 the proportion of the configured netdev_budget 139 the proportion of the configured netdev_budget that is spent on RPS based packet
147 processing during RX softirq cycles. It is fur 140 processing during RX softirq cycles. It is further meant for making current
148 dev_weight adaptable for asymmetric CPU needs 141 dev_weight adaptable for asymmetric CPU needs on RX/TX side of the network stack.
149 (see dev_weight_tx_bias) It is effective on a 142 (see dev_weight_tx_bias) It is effective on a per CPU basis. Determination is based
150 on dev_weight and is calculated multiplicative 143 on dev_weight and is calculated multiplicative (dev_weight * dev_weight_rx_bias).
151 144
152 Default: 1 145 Default: 1
153 146
154 dev_weight_tx_bias 147 dev_weight_tx_bias
155 ------------------ 148 ------------------
156 149
157 Scales the maximum number of packets that can 150 Scales the maximum number of packets that can be processed during a TX softirq cycle.
158 Effective on a per CPU basis. Allows scaling o 151 Effective on a per CPU basis. Allows scaling of current dev_weight for asymmetric
159 net stack processing needs. Be careful to avoi 152 net stack processing needs. Be careful to avoid making TX softirq processing a CPU hog.
160 153
161 Calculation is based on dev_weight (dev_weight 154 Calculation is based on dev_weight (dev_weight * dev_weight_tx_bias).
162 155
163 Default: 1 156 Default: 1
164 157
165 default_qdisc 158 default_qdisc
166 ------------- 159 -------------
167 160
168 The default queuing discipline to use for netw 161 The default queuing discipline to use for network devices. This allows
169 overriding the default of pfifo_fast with an a 162 overriding the default of pfifo_fast with an alternative. Since the default
170 queuing discipline is created without addition 163 queuing discipline is created without additional parameters so is best suited
171 to queuing disciplines that work well without 164 to queuing disciplines that work well without configuration like stochastic
172 fair queue (sfq), CoDel (codel) or fair queue 165 fair queue (sfq), CoDel (codel) or fair queue CoDel (fq_codel). Don't use
173 queuing disciplines like Hierarchical Token Bu 166 queuing disciplines like Hierarchical Token Bucket or Deficit Round Robin
174 which require setting up classes and bandwidth 167 which require setting up classes and bandwidths. Note that physical multiqueue
175 interfaces still use mq as root qdisc, which i 168 interfaces still use mq as root qdisc, which in turn uses this default for its
176 leaves. Virtual devices (like e.g. lo or veth) 169 leaves. Virtual devices (like e.g. lo or veth) ignore this setting and instead
177 default to noqueue. 170 default to noqueue.
178 171
179 Default: pfifo_fast 172 Default: pfifo_fast
180 173
181 busy_read 174 busy_read
182 --------- 175 ---------
183 176
184 Low latency busy poll timeout for socket reads 177 Low latency busy poll timeout for socket reads. (needs CONFIG_NET_RX_BUSY_POLL)
185 Approximate time in us to busy loop waiting fo 178 Approximate time in us to busy loop waiting for packets on the device queue.
186 This sets the default value of the SO_BUSY_POL 179 This sets the default value of the SO_BUSY_POLL socket option.
187 Can be set or overridden per socket by setting 180 Can be set or overridden per socket by setting socket option SO_BUSY_POLL,
188 which is the preferred method of enabling. If 181 which is the preferred method of enabling. If you need to enable the feature
189 globally via sysctl, a value of 50 is recommen 182 globally via sysctl, a value of 50 is recommended.
190 183
191 Will increase power usage. 184 Will increase power usage.
192 185
193 Default: 0 (off) 186 Default: 0 (off)
194 187
195 busy_poll 188 busy_poll
196 ---------------- 189 ----------------
197 Low latency busy poll timeout for poll and sel 190 Low latency busy poll timeout for poll and select. (needs CONFIG_NET_RX_BUSY_POLL)
198 Approximate time in us to busy loop waiting fo 191 Approximate time in us to busy loop waiting for events.
199 Recommended value depends on the number of soc 192 Recommended value depends on the number of sockets you poll on.
200 For several sockets 50, for several hundreds 1 193 For several sockets 50, for several hundreds 100.
201 For more than that you probably want to use ep 194 For more than that you probably want to use epoll.
202 Note that only sockets with SO_BUSY_POLL set w 195 Note that only sockets with SO_BUSY_POLL set will be busy polled,
203 so you want to either selectively set SO_BUSY_ 196 so you want to either selectively set SO_BUSY_POLL on those sockets or set
204 sysctl.net.busy_read globally. 197 sysctl.net.busy_read globally.
205 198
206 Will increase power usage. 199 Will increase power usage.
207 200
208 Default: 0 (off) 201 Default: 0 (off)
209 202
210 mem_pcpu_rsv <<
211 ------------ <<
212 <<
213 Per-cpu reserved forward alloc cache size in p <<
214 <<
215 rmem_default 203 rmem_default
216 ------------ 204 ------------
217 205
218 The default setting of the socket receive buff 206 The default setting of the socket receive buffer in bytes.
219 207
220 rmem_max 208 rmem_max
221 -------- 209 --------
222 210
223 The maximum receive socket buffer size in byte 211 The maximum receive socket buffer size in bytes.
224 212
225 rps_default_mask <<
226 ---------------- <<
227 <<
228 The default RPS CPU mask used on newly created <<
229 mask means RPS disabled by default. <<
230 <<
231 tstamp_allow_data 213 tstamp_allow_data
232 ----------------- 214 -----------------
233 Allow processes to receive tx timestamps loope 215 Allow processes to receive tx timestamps looped together with the original
234 packet contents. If disabled, transmit timesta 216 packet contents. If disabled, transmit timestamp requests from unprivileged
235 processes are dropped unless socket option SOF 217 processes are dropped unless socket option SOF_TIMESTAMPING_OPT_TSONLY is set.
236 218
237 Default: 1 (on) 219 Default: 1 (on)
238 220
239 221
240 wmem_default 222 wmem_default
241 ------------ 223 ------------
242 224
243 The default setting (in bytes) of the socket s 225 The default setting (in bytes) of the socket send buffer.
244 226
245 wmem_max 227 wmem_max
246 -------- 228 --------
247 229
248 The maximum send socket buffer size in bytes. 230 The maximum send socket buffer size in bytes.
249 231
250 message_burst and message_cost 232 message_burst and message_cost
251 ------------------------------ 233 ------------------------------
252 234
253 These parameters are used to limit the warnin 235 These parameters are used to limit the warning messages written to the kernel
254 log from the networking code. They enforc 236 log from the networking code. They enforce a rate limit to make a
255 denial-of-service attack impossible. A higher 237 denial-of-service attack impossible. A higher message_cost factor, results in
256 fewer messages that will be written. Message_b 238 fewer messages that will be written. Message_burst controls when messages will
257 be dropped. The default settings limit wa 239 be dropped. The default settings limit warning messages to one every five
258 seconds. 240 seconds.
259 241
260 warnings 242 warnings
261 -------- 243 --------
262 244
263 This sysctl is now unused. 245 This sysctl is now unused.
264 246
265 This was used to control console messages from 247 This was used to control console messages from the networking stack that
266 occur because of problems on the network like 248 occur because of problems on the network like duplicate address or bad
267 checksums. 249 checksums.
268 250
269 These messages are now emitted at KERN_DEBUG a 251 These messages are now emitted at KERN_DEBUG and can generally be enabled
270 and controlled by the dynamic_debug facility. 252 and controlled by the dynamic_debug facility.
271 253
272 netdev_budget 254 netdev_budget
273 ------------- 255 -------------
274 256
275 Maximum number of packets taken from all inter 257 Maximum number of packets taken from all interfaces in one polling cycle (NAPI
276 poll). In one polling cycle interfaces which a 258 poll). In one polling cycle interfaces which are registered to polling are
277 probed in a round-robin manner. Also, a pollin 259 probed in a round-robin manner. Also, a polling cycle may not exceed
278 netdev_budget_usecs microseconds, even if netd 260 netdev_budget_usecs microseconds, even if netdev_budget has not been
279 exhausted. 261 exhausted.
280 262
281 netdev_budget_usecs 263 netdev_budget_usecs
282 --------------------- 264 ---------------------
283 265
284 Maximum number of microseconds in one NAPI pol 266 Maximum number of microseconds in one NAPI polling cycle. Polling
285 will exit when either netdev_budget_usecs have 267 will exit when either netdev_budget_usecs have elapsed during the
286 poll cycle or the number of packets processed 268 poll cycle or the number of packets processed reaches netdev_budget.
287 269
288 netdev_max_backlog 270 netdev_max_backlog
289 ------------------ 271 ------------------
290 272
291 Maximum number of packets, queued on the INPUT !! 273 Maximum number of packets, queued on the INPUT side, when the interface
292 receives packets faster than kernel can proces 274 receives packets faster than kernel can process them.
293 275
294 netdev_rss_key 276 netdev_rss_key
295 -------------- 277 --------------
296 278
297 RSS (Receive Side Scaling) enabled drivers use 279 RSS (Receive Side Scaling) enabled drivers use a 40 bytes host key that is
298 randomly generated. 280 randomly generated.
299 Some user space might need to gather its conte 281 Some user space might need to gather its content even if drivers do not
300 provide ethtool -x support yet. 282 provide ethtool -x support yet.
301 283
302 :: 284 ::
303 285
304 myhost:~# cat /proc/sys/net/core/netdev_rss_ 286 myhost:~# cat /proc/sys/net/core/netdev_rss_key
305 84:50:f4:00:a8:15:d1:a7:e9:7f:1d:60:35:c7:47 287 84:50:f4:00:a8:15:d1:a7:e9:7f:1d:60:35:c7:47:25:42:97:74:ca:56:bb:b6:a1:d8: ... (52 bytes total)
306 288
307 File contains nul bytes if no driver ever call 289 File contains nul bytes if no driver ever called netdev_rss_key_fill() function.
308 290
309 Note: 291 Note:
310 /proc/sys/net/core/netdev_rss_key contains 5 292 /proc/sys/net/core/netdev_rss_key contains 52 bytes of key,
311 but most drivers only use 40 bytes of it. 293 but most drivers only use 40 bytes of it.
312 294
313 :: 295 ::
314 296
315 myhost:~# ethtool -x eth0 297 myhost:~# ethtool -x eth0
316 RX flow hash indirection table for eth0 with 298 RX flow hash indirection table for eth0 with 8 RX ring(s):
317 0: 0 1 2 3 4 5 299 0: 0 1 2 3 4 5 6 7
318 RSS hash key: 300 RSS hash key:
319 84:50:f4:00:a8:15:d1:a7:e9:7f:1d:60:35:c7:47 301 84:50:f4:00:a8:15:d1:a7:e9:7f:1d:60:35:c7:47:25:42:97:74:ca:56:bb:b6:a1:d8:43:e3:c9:0c:fd:17:55:c2:3a:4d:69:ed:f1:42:89
320 302
321 netdev_tstamp_prequeue 303 netdev_tstamp_prequeue
322 ---------------------- 304 ----------------------
323 305
324 If set to 0, RX packet timestamps can be sampl 306 If set to 0, RX packet timestamps can be sampled after RPS processing, when
325 the target CPU processes packets. It might giv 307 the target CPU processes packets. It might give some delay on timestamps, but
326 permit to distribute the load on several cpus. 308 permit to distribute the load on several cpus.
327 309
328 If set to 1 (default), timestamps are sampled 310 If set to 1 (default), timestamps are sampled as soon as possible, before
329 queueing. 311 queueing.
330 312
331 netdev_unregister_timeout_secs <<
332 ------------------------------ <<
333 <<
334 Unregister network device timeout in seconds. <<
335 This option controls the timeout (in seconds) <<
336 waiting for a network device refcount to drop <<
337 unregistration. A lower value may be useful du <<
338 a leaked reference faster. A larger value may <<
339 warnings on slow/loaded systems. <<
340 Default value is 10, minimum 1, maximum 3600. <<
341 <<
342 skb_defer_max <<
343 ------------- <<
344 <<
345 Max size (in skbs) of the per-cpu list of skbs <<
346 by the cpu which allocated them. Used by TCP s <<
347 <<
348 Default: 64 <<
349 <<
350 optmem_max 313 optmem_max
351 ---------- 314 ----------
352 315
353 Maximum ancillary buffer size allowed per sock 316 Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence
354 of struct cmsghdr structures with appended dat !! 317 of struct cmsghdr structures with appended data.
355 optmem_max as a limit for its internal structu <<
356 <<
357 Default : 128 KB <<
358 318
359 fb_tunnels_only_for_init_net 319 fb_tunnels_only_for_init_net
360 ---------------------------- 320 ----------------------------
361 321
362 Controls if fallback tunnels (like tunl0, gre0 322 Controls if fallback tunnels (like tunl0, gre0, gretap0, erspan0,
363 sit0, ip6tnl0, ip6gre0) are automatically crea !! 323 sit0, ip6tnl0, ip6gre0) are automatically created when a new
364 (a) value = 0; respective fallback tunnels are !! 324 network namespace is created, if corresponding tunnel is present
365 loaded in every net namespaces (backward compa !! 325 in initial network namespace.
366 (b) value = 1; [kcmd value: initns] respective !! 326 If set to 1, these devices are not automatically created, and
367 created only in init net namespace and every o !! 327 user space is responsible for creating them if needed.
368 not have them. <<
369 (c) value = 2; [kcmd value: none] fallback tun <<
370 when a module is loaded in any of the net name <<
371 "2" is pointless after boot if these modules a <<
372 a kernel command-line option that can change t <<
373 Documentation/admin-guide/kernel-parameters.tx <<
374 <<
375 Not creating fallback tunnels gives control to <<
376 whatever is needed only and avoid creating dev <<
377 328
378 Default : 0 (for compatibility reasons) 329 Default : 0 (for compatibility reasons)
379 330
380 devconf_inherit_init_net 331 devconf_inherit_init_net
381 ------------------------ 332 ------------------------
382 333
383 Controls if a new network namespace should inh 334 Controls if a new network namespace should inherit all current
384 settings under /proc/sys/net/{ipv4,ipv6}/conf/ 335 settings under /proc/sys/net/{ipv4,ipv6}/conf/{all,default}/. By
385 default, we keep the current behavior: for IPv 336 default, we keep the current behavior: for IPv4 we inherit all current
386 settings from init_net and for IPv6 we reset a 337 settings from init_net and for IPv6 we reset all settings to default.
387 338
388 If set to 1, both IPv4 and IPv6 settings are f 339 If set to 1, both IPv4 and IPv6 settings are forced to inherit from
389 current ones in init_net. If set to 2, both IP 340 current ones in init_net. If set to 2, both IPv4 and IPv6 settings are
390 forced to reset to their default values. If se !! 341 forced to reset to their default values.
391 settings are forced to inherit from current on <<
392 new netns has been created. <<
393 342
394 Default : 0 (for compatibility reasons) 343 Default : 0 (for compatibility reasons)
395 344
396 txrehash <<
397 -------- <<
398 <<
399 Controls default hash rethink behaviour on soc <<
400 to SOCK_TXREHASH_DEFAULT (i. e. not overridden <<
401 <<
402 If set to 1 (default), hash rethink is perform <<
403 If set to 0, hash rethink is not performed. <<
404 <<
405 gro_normal_batch <<
406 ---------------- <<
407 <<
408 Maximum number of the segments to batch up on <<
409 exits GRO, either as a coalesced superframe or <<
410 GRO has decided not to coalesce, it is placed <<
411 list is then passed to the stack when the numb <<
412 gro_normal_batch limit. <<
413 <<
414 high_order_alloc_disable <<
415 ------------------------ <<
416 <<
417 By default the allocator for page frags tries <<
418 on x86). While the default behavior gives good <<
419 might have hit a contention in page allocation <<
420 true on older kernels (< 5.14) when high-order <<
421 lists. This allows to opt-in for order-0 alloc <<
422 historical importance. <<
423 <<
424 Default: 0 <<
425 <<
426 2. /proc/sys/net/unix - Parameters for Unix do 345 2. /proc/sys/net/unix - Parameters for Unix domain sockets
427 ---------------------------------------------- 346 ----------------------------------------------------------
428 347
429 There is only one file in this directory. 348 There is only one file in this directory.
430 unix_dgram_qlen limits the max number of datag 349 unix_dgram_qlen limits the max number of datagrams queued in Unix domain
431 socket's buffer. It will not take effect unles 350 socket's buffer. It will not take effect unless PF_UNIX flag is specified.
432 351
433 352
434 3. /proc/sys/net/ipv4 - IPV4 settings 353 3. /proc/sys/net/ipv4 - IPV4 settings
435 ------------------------------------- 354 -------------------------------------
436 Please see: Documentation/networking/ip-sysctl !! 355 Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for
437 Documentation/admin-guide/sysctl/net.rst for d !! 356 descriptions of these entries.
438 357
439 358
440 4. Appletalk 359 4. Appletalk
441 ------------ 360 ------------
442 361
443 The /proc/sys/net/appletalk directory holds 362 The /proc/sys/net/appletalk directory holds the Appletalk configuration data
444 when Appletalk is loaded. The configurable par 363 when Appletalk is loaded. The configurable parameters are:
445 364
446 aarp-expiry-time 365 aarp-expiry-time
447 ---------------- 366 ----------------
448 367
449 The amount of time we keep an ARP entry bef 368 The amount of time we keep an ARP entry before expiring it. Used to age out
450 old hosts. 369 old hosts.
451 370
452 aarp-resolve-time 371 aarp-resolve-time
453 ----------------- 372 -----------------
454 373
455 The amount of time we will spend trying to res 374 The amount of time we will spend trying to resolve an Appletalk address.
456 375
457 aarp-retransmit-limit 376 aarp-retransmit-limit
458 --------------------- 377 ---------------------
459 378
460 The number of times we will retransmit a query 379 The number of times we will retransmit a query before giving up.
461 380
462 aarp-tick-time 381 aarp-tick-time
463 -------------- 382 --------------
464 383
465 Controls the rate at which expires are checked 384 Controls the rate at which expires are checked.
466 385
467 The directory /proc/net/appletalk holds the 386 The directory /proc/net/appletalk holds the list of active Appletalk sockets
468 on a machine. 387 on a machine.
469 388
470 The fields indicate the DDP type, the local 389 The fields indicate the DDP type, the local address (in network:node format)
471 the remote address, the size of the transmi 390 the remote address, the size of the transmit pending queue, the size of the
472 received queue (bytes waiting for application 391 received queue (bytes waiting for applications to read) the state and the uid
473 owning the socket. 392 owning the socket.
474 393
475 /proc/net/atalk_iface lists all the interfa 394 /proc/net/atalk_iface lists all the interfaces configured for appletalk.It
476 shows the name of the interface, its Appleta 395 shows the name of the interface, its Appletalk address, the network range on
477 that address (or network number for phase 1 396 that address (or network number for phase 1 networks), and the status of the
478 interface. 397 interface.
479 398
480 /proc/net/atalk_route lists each known netw 399 /proc/net/atalk_route lists each known network route. It lists the target
481 (network) that the route leads to, the router 400 (network) that the route leads to, the router (may be directly connected), the
482 route flags, and the device the route is using 401 route flags, and the device the route is using.
483 402
484 5. TIPC 403 5. TIPC
485 ------- 404 -------
486 405
487 tipc_rmem 406 tipc_rmem
488 --------- 407 ---------
489 408
490 The TIPC protocol now has a tunable for the re 409 The TIPC protocol now has a tunable for the receive memory, similar to the
491 tcp_rmem - i.e. a vector of 3 INTEGERs: (min, 410 tcp_rmem - i.e. a vector of 3 INTEGERs: (min, default, max)
492 411
493 :: 412 ::
494 413
495 # cat /proc/sys/net/tipc/tipc_rmem 414 # cat /proc/sys/net/tipc/tipc_rmem
496 4252725 34021800 68043600 415 4252725 34021800 68043600
497 # 416 #
498 417
499 The max value is set to CONN_OVERLOAD_LIMIT, a 418 The max value is set to CONN_OVERLOAD_LIMIT, and the default and min values
500 are scaled (shifted) versions of that same val 419 are scaled (shifted) versions of that same value. Note that the min value
501 is not at this point in time used in any meani 420 is not at this point in time used in any meaningful way, but the triplet is
502 preserved in order to be consistent with thing 421 preserved in order to be consistent with things like tcp_rmem.
503 422
504 named_timeout 423 named_timeout
505 ------------- 424 -------------
506 425
507 TIPC name table updates are distributed asynch 426 TIPC name table updates are distributed asynchronously in a cluster, without
508 any form of transaction handling. This means t 427 any form of transaction handling. This means that different race scenarios are
509 possible. One such is that a name withdrawal s 428 possible. One such is that a name withdrawal sent out by one node and received
510 by another node may arrive after a second, ove 429 by another node may arrive after a second, overlapping name publication already
511 has been accepted from a third node, although 430 has been accepted from a third node, although the conflicting updates
512 originally may have been issued in the correct 431 originally may have been issued in the correct sequential order.
513 If named_timeout is nonzero, failed topology u 432 If named_timeout is nonzero, failed topology updates will be placed on a defer
514 queue until another event arrives that clears 433 queue until another event arrives that clears the error, or until the timeout
515 expires. Value is in milliseconds. 434 expires. Value is in milliseconds.
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.