diff options
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt | 10 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/brcm,systemport.txt | 5 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/cpsw.txt | 3 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/dsa/dsa.txt | 20 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/dsa/marvell.txt | 93 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/meson-dwmac.txt | 16 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/snps,dwc-qos-ethernet.txt | 3 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/stmmac.txt | 3 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/net/wireless/ieee80211.txt | 24 | ||||
-rw-r--r-- | Documentation/driver-api/80211/cfg80211.rst | 3 | ||||
-rw-r--r-- | Documentation/networking/dsa/dsa.txt | 24 | ||||
-rw-r--r-- | Documentation/networking/ip-sysctl.txt | 40 | ||||
-rw-r--r-- | Documentation/networking/packet_mmap.txt | 9 | ||||
-rw-r--r-- | Documentation/networking/regulatory.txt | 8 | ||||
-rw-r--r-- | Documentation/siphash.txt | 175 | ||||
-rw-r--r-- | Documentation/sysctl/net.txt | 21 |
16 files changed, 355 insertions, 102 deletions
diff --git a/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt b/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt index fb40891ee606..9a734d808aa7 100644 --- a/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt +++ b/Documentation/devicetree/bindings/net/brcm,bcm7445-switch-v4.0.txt @@ -2,7 +2,7 @@ Required properties: -- compatible: should be "brcm,bcm7445-switch-v4.0" +- compatible: should be "brcm,bcm7445-switch-v4.0" or "brcm,bcm7278-switch-v4.0" - reg: addresses and length of the register sets for the device, must be 6 pairs of register addresses and lengths - interrupts: interrupts for the devices, must be two interrupts @@ -41,6 +41,13 @@ Optional properties: Admission Control Block supports reporting the number of packets in-flight in a switch queue +Port subnodes: + +Optional properties: + +- brcm,use-bcm-hdr: boolean property, if present, indicates that the switch + port has Broadcom tags enabled (per-packet metadata) + Example: switch_top@f0b00000 { @@ -114,6 +121,7 @@ switch_top@f0b00000 { port@0 { label = "gphy"; reg = <0>; + brcm,use-bcm-hdr; }; ... }; diff --git a/Documentation/devicetree/bindings/net/brcm,systemport.txt b/Documentation/devicetree/bindings/net/brcm,systemport.txt index 877da34145b0..83f29e0e11ba 100644 --- a/Documentation/devicetree/bindings/net/brcm,systemport.txt +++ b/Documentation/devicetree/bindings/net/brcm,systemport.txt @@ -1,7 +1,10 @@ * Broadcom BCM7xxx Ethernet Systemport Controller (SYSTEMPORT) Required properties: -- compatible: should be one of "brcm,systemport-v1.00" or "brcm,systemport" +- compatible: should be one of: + "brcm,systemport-v1.00" + "brcm,systemportlite-v1.00" or + "brcm,systemport" - reg: address and length of the register set for the device. - interrupts: interrupts for the device, first cell must be for the rx interrupts, and the second cell should be for the transmit queues. An diff --git a/Documentation/devicetree/bindings/net/cpsw.txt b/Documentation/devicetree/bindings/net/cpsw.txt index ebda7c93453a..7cc15c96ea95 100644 --- a/Documentation/devicetree/bindings/net/cpsw.txt +++ b/Documentation/devicetree/bindings/net/cpsw.txt @@ -23,7 +23,6 @@ Required properties: Optional properties: - ti,hwmods : Must be "cpgmac0" -- no_bd_ram : Must be 0 or 1 - dual_emac : Specifies Switch to act as Dual EMAC - syscon : Phandle to the system control device node, which is the control module device of the am33x @@ -70,7 +69,6 @@ Examples: cpdma_channels = <8>; ale_entries = <1024>; bd_ram_size = <0x2000>; - no_bd_ram = <0>; rx_descs = <64>; mac_control = <0x20>; slaves = <2>; @@ -99,7 +97,6 @@ Examples: cpdma_channels = <8>; ale_entries = <1024>; bd_ram_size = <0x2000>; - no_bd_ram = <0>; rx_descs = <64>; mac_control = <0x20>; slaves = <2>; diff --git a/Documentation/devicetree/bindings/net/dsa/dsa.txt b/Documentation/devicetree/bindings/net/dsa/dsa.txt index a4a570fb2494..cfe8f64eca4f 100644 --- a/Documentation/devicetree/bindings/net/dsa/dsa.txt +++ b/Documentation/devicetree/bindings/net/dsa/dsa.txt @@ -34,13 +34,9 @@ Required properties: Each port children node must have the following mandatory properties: - reg : Describes the port address in the switch -- label : Describes the label associated with this port, which - will become the netdev name. Special labels are - "cpu" to indicate a CPU port and "dsa" to - indicate an uplink/downlink port between switches in - the cluster. -A port labelled "dsa" has the following mandatory property: +An uplink/downlink port between switches in the cluster has the following +mandatory property: - link : Should be a list of phandles to other switch's DSA port. This port is used as the outgoing port @@ -48,12 +44,17 @@ A port labelled "dsa" has the following mandatory property: information must be given, not just the one hop routes to neighbouring switches. -A port labelled "cpu" has the following mandatory property: +A CPU port has the following mandatory property: - ethernet : Should be a phandle to a valid Ethernet device node. This host device is what the switch port is connected to. +A user port has the following optional property: + +- label : Describes the label associated with this port, which + will become the netdev name. + Port child nodes may also contain the following optional standardised properties, described in binding documents: @@ -107,7 +108,6 @@ linked into one DSA cluster. switch0port5: port@5 { reg = <5>; - label = "dsa"; phy-mode = "rgmii-txid"; link = <&switch1port6 &switch2port9>; @@ -119,7 +119,6 @@ linked into one DSA cluster. port@6 { reg = <6>; - label = "cpu"; ethernet = <&fec1>; fixed-link { speed = <100>; @@ -165,7 +164,6 @@ linked into one DSA cluster. switch1port5: port@5 { reg = <5>; - label = "dsa"; link = <&switch2port9>; phy-mode = "rgmii-txid"; fixed-link { @@ -176,7 +174,6 @@ linked into one DSA cluster. switch1port6: port@6 { reg = <6>; - label = "dsa"; phy-mode = "rgmii-txid"; link = <&switch0port5>; fixed-link { @@ -255,7 +252,6 @@ linked into one DSA cluster. switch2port9: port@9 { reg = <9>; - label = "dsa"; phy-mode = "rgmii-txid"; link = <&switch1port5 &switch0port5>; diff --git a/Documentation/devicetree/bindings/net/dsa/marvell.txt b/Documentation/devicetree/bindings/net/dsa/marvell.txt index b3dd6b40e0de..7ef9dbb08957 100644 --- a/Documentation/devicetree/bindings/net/dsa/marvell.txt +++ b/Documentation/devicetree/bindings/net/dsa/marvell.txt @@ -14,9 +14,9 @@ The properties described here are those specific to Marvell devices. Additional required and optional properties can be found in dsa.txt. Required properties: -- compatible : Should be one of "marvell,mv88e6085" or - "marvell,mv88e6190" -- reg : Address on the MII bus for the switch. +- compatible : Should be one of "marvell,mv88e6085" or + "marvell,mv88e6190" +- reg : Address on the MII bus for the switch. Optional properties: @@ -26,30 +26,67 @@ Optional properties: - interrupt-controller : Indicates the switch is itself an interrupt controller. This is used for the PHY interrupts. #interrupt-cells = <2> : Controller uses two cells, number and flag -- mdio : container of PHY and devices on the switches MDIO - bus +- mdio : Container of PHY and devices on the switches MDIO + bus. +- mdio? : Container of PHYs and devices on the external MDIO + bus. The node must contains a compatible string of + "marvell,mv88e6xxx-mdio-external" + Example: - mdio { - #address-cells = <1>; - #size-cells = <0>; - interrupt-parent = <&gpio0>; - interrupts = <27 IRQ_TYPE_LEVEL_LOW>; - interrupt-controller; - #interrupt-cells = <2>; - - switch0: switch@0 { - compatible = "marvell,mv88e6085"; - reg = <0>; - reset-gpios = <&gpio5 1 GPIO_ACTIVE_LOW>; - }; - mdio { - #address-cells = <1>; - #size-cells = <0>; - switch1phy0: switch1phy0@0 { - reg = <0>; - interrupt-parent = <&switch0>; - interrupts = <0 IRQ_TYPE_LEVEL_HIGH>; - }; - }; - }; + mdio { + #address-cells = <1>; + #size-cells = <0>; + interrupt-parent = <&gpio0>; + interrupts = <27 IRQ_TYPE_LEVEL_LOW>; + interrupt-controller; + #interrupt-cells = <2>; + + switch0: switch@0 { + compatible = "marvell,mv88e6085"; + reg = <0>; + reset-gpios = <&gpio5 1 GPIO_ACTIVE_LOW>; + }; + mdio { + #address-cells = <1>; + #size-cells = <0>; + switch1phy0: switch1phy0@0 { + reg = <0>; + interrupt-parent = <&switch0>; + interrupts = <0 IRQ_TYPE_LEVEL_HIGH>; + }; + }; + }; + + mdio { + #address-cells = <1>; + #size-cells = <0>; + interrupt-parent = <&gpio0>; + interrupts = <27 IRQ_TYPE_LEVEL_LOW>; + interrupt-controller; + #interrupt-cells = <2>; + + switch0: switch@0 { + compatible = "marvell,mv88e6390"; + reg = <0>; + reset-gpios = <&gpio5 1 GPIO_ACTIVE_LOW>; + }; + mdio { + #address-cells = <1>; + #size-cells = <0>; + switch1phy0: switch1phy0@0 { + reg = <0>; + interrupt-parent = <&switch0>; + interrupts = <0 IRQ_TYPE_LEVEL_HIGH>; + }; + }; + + mdio1 { + compatible = "marvell,mv88e6xxx-mdio-external"; + #address-cells = <1>; + #size-cells = <0>; + switch1phy9: switch1phy0@9 { + reg = <9>; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/net/meson-dwmac.txt b/Documentation/devicetree/bindings/net/meson-dwmac.txt index 89e62ddc69ca..0703ad3f3c1e 100644 --- a/Documentation/devicetree/bindings/net/meson-dwmac.txt +++ b/Documentation/devicetree/bindings/net/meson-dwmac.txt @@ -25,6 +25,22 @@ Required properties on Meson8b and newer: - "clkin0" - first parent clock of the internal mux - "clkin1" - second parent clock of the internal mux +Optional properties on Meson8b and newer: +- amlogic,tx-delay-ns: The internal RGMII TX clock delay (provided + by this driver) in nanoseconds. Allowed values + are: 0ns, 2ns, 4ns, 6ns. + When phy-mode is set to "rgmii" then the TX + delay should be explicitly configured. When + not configured a fallback of 2ns is used. + When the phy-mode is set to either "rgmii-id" + or "rgmii-txid" the TX clock delay is already + provided by the PHY. In that case this + property should be set to 0ns (which disables + the TX clock delay in the MAC to prevent the + clock from going off because both PHY and MAC + are adding a delay). + Any configuration is ignored when the phy-mode + is set to "rmii". Example for Meson6: diff --git a/Documentation/devicetree/bindings/net/snps,dwc-qos-ethernet.txt b/Documentation/devicetree/bindings/net/snps,dwc-qos-ethernet.txt index d93f71ce8346..21d27aa4c68c 100644 --- a/Documentation/devicetree/bindings/net/snps,dwc-qos-ethernet.txt +++ b/Documentation/devicetree/bindings/net/snps,dwc-qos-ethernet.txt @@ -1,5 +1,8 @@ * Synopsys DWC Ethernet QoS IP version 4.10 driver (GMAC) +This binding is deprecated, but it continues to be supported, but new +features should be preferably added to the stmmac binding document. + This binding supports the Synopsys Designware Ethernet QoS (Quality Of Service) IP block. The IP supports multiple options for bus type, clocking and reset structure, and feature list. Consequently, a number of properties and list diff --git a/Documentation/devicetree/bindings/net/stmmac.txt b/Documentation/devicetree/bindings/net/stmmac.txt index 128da752fec9..d3bfc2b30fb5 100644 --- a/Documentation/devicetree/bindings/net/stmmac.txt +++ b/Documentation/devicetree/bindings/net/stmmac.txt @@ -49,6 +49,8 @@ Optional properties: - snps,force_sf_dma_mode Force DMA to use the Store and Forward mode for both tx and rx. This flag is ignored if force_thresh_dma_mode is set. +- snps,en-tx-lpi-clockgating Enable gating of the MAC TX clock during + TX low-power mode - snps,multicast-filter-bins: Number of multicast filter hash bins supported by this device instance - snps,perfect-filter-entries: Number of perfect filter entries supported @@ -65,7 +67,6 @@ Optional properties: - snps,wr_osr_lmt: max write outstanding req. limit - snps,rd_osr_lmt: max read outstanding req. limit - snps,kbbe: do not cross 1KiB boundary. - - snps,axi_all: align address - snps,blen: this is a vector of supported burst length. - snps,fb: fixed-burst - snps,mb: mixed-burst diff --git a/Documentation/devicetree/bindings/net/wireless/ieee80211.txt b/Documentation/devicetree/bindings/net/wireless/ieee80211.txt new file mode 100644 index 000000000000..f6442b1397f5 --- /dev/null +++ b/Documentation/devicetree/bindings/net/wireless/ieee80211.txt @@ -0,0 +1,24 @@ +Common IEEE 802.11 properties + +This provides documentation of common properties that are valid for all wireless +devices. + +Optional properties: + - ieee80211-freq-limit : list of supported frequency ranges in KHz. This can be + used for devices that in a given config support less channels than + normally. It may happen chipset supports a wide wireless band but it is + limited to some part of it due to used antennas or power amplifier. + An example case for this can be tri-band wireless router with two + identical chipsets used for two different 5 GHz subbands. Using them + incorrectly could not work or decrease performance noticeably. + +Example: + +pcie@0,0 { + reg = <0x0000 0 0 0 0>; + wifi@0,0 { + reg = <0x0000 0 0 0 0>; + ieee80211-freq-limit = <2402000 2482000>, + <5170000 5250000>; + }; +}; diff --git a/Documentation/driver-api/80211/cfg80211.rst b/Documentation/driver-api/80211/cfg80211.rst index b1e149ea6fee..eca534ab6172 100644 --- a/Documentation/driver-api/80211/cfg80211.rst +++ b/Documentation/driver-api/80211/cfg80211.rst @@ -45,6 +45,9 @@ Device registration :functions: wiphy_new .. kernel-doc:: include/net/cfg80211.h + :functions: wiphy_read_of_freq_limits + +.. kernel-doc:: include/net/cfg80211.h :functions: wiphy_register .. kernel-doc:: include/net/cfg80211.h diff --git a/Documentation/networking/dsa/dsa.txt b/Documentation/networking/dsa/dsa.txt index 63912ef34606..b8b40753133e 100644 --- a/Documentation/networking/dsa/dsa.txt +++ b/Documentation/networking/dsa/dsa.txt @@ -295,7 +295,6 @@ DSA currently leverages the following subsystems: - MDIO/PHY library: drivers/net/phy/phy.c, mdio_bus.c - Switchdev: net/switchdev/* - Device Tree for various of_* functions -- HWMON: drivers/hwmon/* MDIO/PHY library ---------------- @@ -349,12 +348,6 @@ Documentation/devicetree/bindings/net/dsa/dsa.txt. PHY/MDIO library helper functions such as of_get_phy_mode(), of_phy_connect() are also used to query per-port PHY specific details: interface connection, MDIO bus location etc.. -HWMON ------ - -Some switch drivers feature internal temperature sensors which are exposed as -regular HWMON devices in /sys/class/hwmon/. - Driver development ================== @@ -495,23 +488,6 @@ Power management BR_STATE_DISABLED and propagating changes to the hardware if this port is disabled while being a bridge member -Hardware monitoring -------------------- - -These callbacks are only available if CONFIG_NET_DSA_HWMON is enabled: - -- get_temp: this function queries the given switch for its temperature - -- get_temp_limit: this function returns the switch current maximum temperature - limit - -- set_temp_limit: this function configures the maximum temperature limit allowed - -- get_temp_alarm: this function returns the critical temperature threshold - returning an alarm notification - -See Documentation/hwmon/sysfs-interface for details. - Bridge layer ------------ diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 7dd65c9cf707..17f2e7791042 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -246,21 +246,12 @@ tcp_dsack - BOOLEAN Allows TCP to send "duplicate" SACKs. tcp_early_retrans - INTEGER - Enable Early Retransmit (ER), per RFC 5827. ER lowers the threshold - for triggering fast retransmit when the amount of outstanding data is - small and when no previously unsent data can be transmitted (such - that limited transmit could be used). Also controls the use of - Tail loss probe (TLP) that converts RTOs occurring due to tail - losses into fast recovery (draft-dukkipati-tcpm-tcp-loss-probe-01). + Tail loss probe (TLP) converts RTOs occurring due to tail + losses into fast recovery (draft-ietf-tcpm-rack). Note that + TLP requires RACK to function properly (see tcp_recovery below) Possible values: - 0 disables ER - 1 enables ER - 2 enables ER but delays fast recovery and fast retransmit - by a fourth of RTT. This mitigates connection falsely - recovers when network has a small degree of reordering - (less than 3 packets). - 3 enables delayed ER and TLP. - 4 enables TLP only. + 0 disables TLP + 3 or 4 enables TLP Default: 3 tcp_ecn - INTEGER @@ -712,18 +703,6 @@ tcp_thin_linear_timeouts - BOOLEAN Documentation/networking/tcp-thin.txt Default: 0 -tcp_thin_dupack - BOOLEAN - Enable dynamic triggering of retransmissions after one dupACK - for thin streams. If set, a check is performed upon reception - of a dupACK to determine if the stream is thin (less than 4 - packets in flight). As long as the stream is found to be thin, - data is retransmitted on the first received dupACK. This - improves retransmission latency for non-aggressive thin - streams, often found to be time-dependent. - For more information on thin streams, see - Documentation/networking/tcp-thin.txt - Default: 0 - tcp_limit_output_bytes - INTEGER Controls TCP Small Queue limit per tcp socket. TCP bulk sender tends to increase packets in flight until it @@ -843,6 +822,15 @@ ip_local_reserved_ports - list of comma separated ranges Default: Empty +ip_unprivileged_port_start - INTEGER + This is a per-namespace sysctl. It defines the first + unprivileged port in the network namespace. Privileged ports + require root or CAP_NET_BIND_SERVICE in order to bind to them. + To disable all privileged ports, set this to 0. It may not + overlap with the ip_local_reserved_ports range. + + Default: 1024 + ip_nonlocal_bind - BOOLEAN If set, allows processes to bind() to non-local IP addresses, which can be quite useful - but may break some applications. diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index daa015af16a0..f3b9e507ab05 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -565,7 +565,7 @@ TPACKET_V1 --> TPACKET_V2: (void *)hdr + TPACKET_ALIGN(sizeof(struct tpacket_hdr)) TPACKET_V2 --> TPACKET_V3: - - Flexible buffer implementation: + - Flexible buffer implementation for RX_RING: 1. Blocks can be configured with non-static frame-size 2. Read/poll is at a block-level (as opposed to packet-level) 3. Added poll timeout to avoid indefinite user-space wait @@ -574,7 +574,12 @@ TPACKET_V2 --> TPACKET_V3: 4.1 block::timeout 4.2 tpkt_hdr::sk_rxhash - RX Hash data available in user space - - Currently only RX_RING available + - TX_RING semantics are conceptually similar to TPACKET_V2; + use tpacket3_hdr instead of tpacket2_hdr, and TPACKET3_HDRLEN + instead of TPACKET2_HDRLEN. In the current implementation, + the tp_next_offset field in the tpacket3_hdr MUST be set to + zero, indicating that the ring does not hold variable sized frames. + Packets with non-zero values of tp_next_offset will be dropped. ------------------------------------------------------------------------------- + AF_PACKET fanout mode diff --git a/Documentation/networking/regulatory.txt b/Documentation/networking/regulatory.txt index 356f791af574..7818b5fe448b 100644 --- a/Documentation/networking/regulatory.txt +++ b/Documentation/networking/regulatory.txt @@ -156,12 +156,12 @@ struct ieee80211_regdomain mydriver_jp_regdom = { //.alpha2 = "99", /* If I have no alpha2 to map it to */ .reg_rules = { /* IEEE 802.11b/g, channels 1..14 */ - REG_RULE(2412-20, 2484+20, 40, 6, 20, 0), + REG_RULE(2412-10, 2484+10, 40, 6, 20, 0), /* IEEE 802.11a, channels 34..48 */ - REG_RULE(5170-20, 5240+20, 40, 6, 20, + REG_RULE(5170-10, 5240+10, 40, 6, 20, NL80211_RRF_NO_IR), /* IEEE 802.11a, channels 52..64 */ - REG_RULE(5260-20, 5320+20, 40, 6, 20, + REG_RULE(5260-10, 5320+10, 40, 6, 20, NL80211_RRF_NO_IR| NL80211_RRF_DFS), } @@ -205,7 +205,7 @@ the data in regdb.c as an alternative to using CRDA. The file net/wireless/db.txt should be kept up-to-date with the db.txt file available in the git repository here: - git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-regdb.git + git://git.kernel.org/pub/scm/linux/kernel/git/sforshee/wireless-regdb.git Again, most users in most situations should be using the CRDA package provided with their distribution, and in most other situations users diff --git a/Documentation/siphash.txt b/Documentation/siphash.txt new file mode 100644 index 000000000000..908d348ff777 --- /dev/null +++ b/Documentation/siphash.txt @@ -0,0 +1,175 @@ + SipHash - a short input PRF +----------------------------------------------- +Written by Jason A. Donenfeld <jason@zx2c4.com> + +SipHash is a cryptographically secure PRF -- a keyed hash function -- that +performs very well for short inputs, hence the name. It was designed by +cryptographers Daniel J. Bernstein and Jean-Philippe Aumasson. It is intended +as a replacement for some uses of: `jhash`, `md5_transform`, `sha_transform`, +and so forth. + +SipHash takes a secret key filled with randomly generated numbers and either +an input buffer or several input integers. It spits out an integer that is +indistinguishable from random. You may then use that integer as part of secure +sequence numbers, secure cookies, or mask it off for use in a hash table. + +1. Generating a key + +Keys should always be generated from a cryptographically secure source of +random numbers, either using get_random_bytes or get_random_once: + +siphash_key_t key; +get_random_bytes(&key, sizeof(key)); + +If you're not deriving your key from here, you're doing it wrong. + +2. Using the functions + +There are two variants of the function, one that takes a list of integers, and +one that takes a buffer: + +u64 siphash(const void *data, size_t len, const siphash_key_t *key); + +And: + +u64 siphash_1u64(u64, const siphash_key_t *key); +u64 siphash_2u64(u64, u64, const siphash_key_t *key); +u64 siphash_3u64(u64, u64, u64, const siphash_key_t *key); +u64 siphash_4u64(u64, u64, u64, u64, const siphash_key_t *key); +u64 siphash_1u32(u32, const siphash_key_t *key); +u64 siphash_2u32(u32, u32, const siphash_key_t *key); +u64 siphash_3u32(u32, u32, u32, const siphash_key_t *key); +u64 siphash_4u32(u32, u32, u32, u32, const siphash_key_t *key); + +If you pass the generic siphash function something of a constant length, it +will constant fold at compile-time and automatically choose one of the +optimized functions. + +3. Hashtable key function usage: + +struct some_hashtable { + DECLARE_HASHTABLE(hashtable, 8); + siphash_key_t key; +}; + +void init_hashtable(struct some_hashtable *table) +{ + get_random_bytes(&table->key, sizeof(table->key)); +} + +static inline hlist_head *some_hashtable_bucket(struct some_hashtable *table, struct interesting_input *input) +{ + return &table->hashtable[siphash(input, sizeof(*input), &table->key) & (HASH_SIZE(table->hashtable) - 1)]; +} + +You may then iterate like usual over the returned hash bucket. + +4. Security + +SipHash has a very high security margin, with its 128-bit key. So long as the +key is kept secret, it is impossible for an attacker to guess the outputs of +the function, even if being able to observe many outputs, since 2^128 outputs +is significant. + +Linux implements the "2-4" variant of SipHash. + +5. Struct-passing Pitfalls + +Often times the XuY functions will not be large enough, and instead you'll +want to pass a pre-filled struct to siphash. When doing this, it's important +to always ensure the struct has no padding holes. The easiest way to do this +is to simply arrange the members of the struct in descending order of size, +and to use offsetendof() instead of sizeof() for getting the size. For +performance reasons, if possible, it's probably a good thing to align the +struct to the right boundary. Here's an example: + +const struct { + struct in6_addr saddr; + u32 counter; + u16 dport; +} __aligned(SIPHASH_ALIGNMENT) combined = { + .saddr = *(struct in6_addr *)saddr, + .counter = counter, + .dport = dport +}; +u64 h = siphash(&combined, offsetofend(typeof(combined), dport), &secret); + +6. Resources + +Read the SipHash paper if you're interested in learning more: +https://131002.net/siphash/siphash.pdf + + +~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~ + +HalfSipHash - SipHash's insecure younger cousin +----------------------------------------------- +Written by Jason A. Donenfeld <jason@zx2c4.com> + +On the off-chance that SipHash is not fast enough for your needs, you might be +able to justify using HalfSipHash, a terrifying but potentially useful +possibility. HalfSipHash cuts SipHash's rounds down from "2-4" to "1-3" and, +even scarier, uses an easily brute-forcable 64-bit key (with a 32-bit output) +instead of SipHash's 128-bit key. However, this may appeal to some +high-performance `jhash` users. + +Danger! + +Do not ever use HalfSipHash except for as a hashtable key function, and only +then when you can be absolutely certain that the outputs will never be +transmitted out of the kernel. This is only remotely useful over `jhash` as a +means of mitigating hashtable flooding denial of service attacks. + +1. Generating a key + +Keys should always be generated from a cryptographically secure source of +random numbers, either using get_random_bytes or get_random_once: + +hsiphash_key_t key; +get_random_bytes(&key, sizeof(key)); + +If you're not deriving your key from here, you're doing it wrong. + +2. Using the functions + +There are two variants of the function, one that takes a list of integers, and +one that takes a buffer: + +u32 hsiphash(const void *data, size_t len, const hsiphash_key_t *key); + +And: + +u32 hsiphash_1u32(u32, const hsiphash_key_t *key); +u32 hsiphash_2u32(u32, u32, const hsiphash_key_t *key); +u32 hsiphash_3u32(u32, u32, u32, const hsiphash_key_t *key); +u32 hsiphash_4u32(u32, u32, u32, u32, const hsiphash_key_t *key); + +If you pass the generic hsiphash function something of a constant length, it +will constant fold at compile-time and automatically choose one of the +optimized functions. + +3. Hashtable key function usage: + +struct some_hashtable { + DECLARE_HASHTABLE(hashtable, 8); + hsiphash_key_t key; +}; + +void init_hashtable(struct some_hashtable *table) +{ + get_random_bytes(&table->key, sizeof(table->key)); +} + +static inline hlist_head *some_hashtable_bucket(struct some_hashtable *table, struct interesting_input *input) +{ + return &table->hashtable[hsiphash(input, sizeof(*input), &table->key) & (HASH_SIZE(table->hashtable) - 1)]; +} + +You may then iterate like usual over the returned hash bucket. + +4. Performance + +HalfSipHash is roughly 3 times slower than JenkinsHash. For many replacements, +this will not be a problem, as the hashtable lookup isn't the bottleneck. And +in general, this is probably a good sacrifice to make for the security and DoS +resistance of HalfSipHash. diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt index f0480f7ea740..b80fbd4e5575 100644 --- a/Documentation/sysctl/net.txt +++ b/Documentation/sysctl/net.txt @@ -61,6 +61,27 @@ The maximum number of packets that kernel can handle on a NAPI interrupt, it's a Per-CPU variable. Default: 64 +dev_weight_rx_bias +-------------- + +RPS (e.g. RFS, aRFS) processing is competing with the registered NAPI poll function +of the driver for the per softirq cycle netdev_budget. This parameter influences +the proportion of the configured netdev_budget that is spent on RPS based packet +processing during RX softirq cycles. It is further meant for making current +dev_weight adaptable for asymmetric CPU needs on RX/TX side of the network stack. +(see dev_weight_tx_bias) It is effective on a per CPU basis. Determination is based +on dev_weight and is calculated multiplicative (dev_weight * dev_weight_rx_bias). +Default: 1 + +dev_weight_tx_bias +-------------- + +Scales the maximum number of packets that can be processed during a TX softirq cycle. +Effective on a per CPU basis. Allows scaling of current dev_weight for asymmetric +net stack processing needs. Be careful to avoid making TX softirq processing a CPU hog. +Calculation is based on dev_weight (dev_weight * dev_weight_tx_bias). +Default: 1 + default_qdisc -------------- |