diff options
Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/LICENSE.qlge | 46 | ||||
| -rw-r--r-- | Documentation/networking/can.txt | 44 | ||||
| -rw-r--r-- | Documentation/networking/multiqueue.txt | 54 | ||||
| -rw-r--r-- | Documentation/networking/phonet.txt | 175 | ||||
| -rw-r--r-- | Documentation/networking/regulatory.txt | 194 | ||||
| -rw-r--r-- | Documentation/networking/tproxy.txt | 85 |
6 files changed, 593 insertions, 5 deletions
diff --git a/Documentation/networking/LICENSE.qlge b/Documentation/networking/LICENSE.qlge new file mode 100644 index 0000000..123b6ed --- /dev/null +++ b/Documentation/networking/LICENSE.qlge @@ -0,0 +1,46 @@ +Copyright (c) 2003-2008 QLogic Corporation +QLogic Linux Networking HBA Driver + +This program includes a device driver for Linux 2.6 that may be +distributed with QLogic hardware specific firmware binary file. +You may modify and redistribute the device driver code under the +GNU General Public License as published by the Free Software +Foundation (version 2 or a later version). + +You may redistribute the hardware specific firmware binary file +under the following terms: + + 1. Redistribution of source code (only if applicable), + must retain the above copyright notice, this list of + conditions and the following disclaimer. + + 2. Redistribution in binary form must reproduce the above + copyright notice, this list of conditions and the + following disclaimer in the documentation and/or other + materials provided with the distribution. + + 3. The name of QLogic Corporation may not be used to + endorse or promote products derived from this software + without specific prior written permission + +REGARDLESS OF WHAT LICENSING MECHANISM IS USED OR APPLICABLE, +THIS PROGRAM IS PROVIDED BY QLOGIC CORPORATION "AS IS'' AND ANY +EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR +BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, +EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED +TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON +ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF SUCH DAMAGE. + +USER ACKNOWLEDGES AND AGREES THAT USE OF THIS PROGRAM WILL NOT +CREATE OR GIVE GROUNDS FOR A LICENSE BY IMPLICATION, ESTOPPEL, OR +OTHERWISE IN ANY INTELLECTUAL PROPERTY RIGHTS (PATENT, COPYRIGHT, +TRADE SECRET, MASK WORK, OR OTHER PROPRIETARY RIGHT) EMBODIED IN +ANY OTHER QLOGIC HARDWARE OR SOFTWARE EITHER SOLELY OR IN +COMBINATION WITH THIS PROGRAM. + diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt index 297ba7b..2035bc4 100644 --- a/Documentation/networking/can.txt +++ b/Documentation/networking/can.txt @@ -35,8 +35,9 @@ This file contains 6.1 general settings 6.2 local loopback of sent frames 6.3 CAN controller hardware filters - 6.4 currently supported CAN hardware - 6.5 todo + 6.4 The virtual CAN driver (vcan) + 6.5 currently supported CAN hardware + 6.6 todo 7 Credits @@ -584,7 +585,42 @@ solution for a couple of reasons: @133MHz with four SJA1000 CAN controllers from 2002 under heavy bus load without any problems ... - 6.4 currently supported CAN hardware (September 2007) + 6.4 The virtual CAN driver (vcan) + + Similar to the network loopback devices, vcan offers a virtual local + CAN interface. A full qualified address on CAN consists of + + - a unique CAN Identifier (CAN ID) + - the CAN bus this CAN ID is transmitted on (e.g. can0) + + so in common use cases more than one virtual CAN interface is needed. + + The virtual CAN interfaces allow the transmission and reception of CAN + frames without real CAN controller hardware. Virtual CAN network + devices are usually named 'vcanX', like vcan0 vcan1 vcan2 ... + When compiled as a module the virtual CAN driver module is called vcan.ko + + Since Linux Kernel version 2.6.24 the vcan driver supports the Kernel + netlink interface to create vcan network devices. The creation and + removal of vcan network devices can be managed with the ip(8) tool: + + - Create a virtual CAN network interface: + ip link add type vcan + + - Create a virtual CAN network interface with a specific name 'vcan42': + ip link add dev vcan42 type vcan + + - Remove a (virtual CAN) network interface 'vcan42': + ip link del vcan42 + + The tool 'vcan' from the SocketCAN SVN repository on BerliOS is obsolete. + + Virtual CAN network device creation in older Kernels: + In Linux Kernel versions < 2.6.24 the vcan driver creates 4 vcan + netdevices at module load time by default. This value can be changed + with the module parameter 'numdev'. E.g. 'modprobe vcan numdev=8' + + 6.5 currently supported CAN hardware On the project website http://developer.berlios.de/projects/socketcan there are different drivers available: @@ -603,7 +639,7 @@ solution for a couple of reasons: Please check the Mailing Lists on the berlios OSS project website. - 6.5 todo (September 2007) + 6.6 todo The configuration interface for CAN network drivers is still an open issue that has not been finalized in the socketcan project. Also the diff --git a/Documentation/networking/multiqueue.txt b/Documentation/networking/multiqueue.txt index d391ea6..4caa0e3 100644 --- a/Documentation/networking/multiqueue.txt +++ b/Documentation/networking/multiqueue.txt @@ -24,4 +24,56 @@ netif_{start|stop|wake}_subqueue() functions to manage each queue while the device is still operational. netdev->queue_lock is still used when the device comes online or when it's completely shut down (unregister_netdev(), etc.). -Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com> + +Section 2: Qdisc support for multiqueue devices + +----------------------------------------------- + +Currently two qdiscs are optimized for multiqueue devices. The first is the +default pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue. +A new round-robin qdisc, sch_multiq also supports multiple hardware queues. The +qdisc is responsible for classifying the skb's and then directing the skb's to +bands and queues based on the value in skb->queue_mapping. Use this field in +the base driver to determine which queue to send the skb to. + +sch_multiq has been added for hardware that wishes to avoid head-of-line +blocking. It will cycle though the bands and verify that the hardware queue +associated with the band is not stopped prior to dequeuing a packet. + +On qdisc load, the number of bands is based on the number of queues on the +hardware. Once the association is made, any skb with skb->queue_mapping set, +will be queued to the band associated with the hardware queue. + + +Section 3: Brief howto using MULTIQ for multiqueue devices +--------------------------------------------------------------- + +The userspace command 'tc,' part of the iproute2 package, is used to configure +qdiscs. To add the MULTIQ qdisc to your network device, assuming the device +is called eth0, run the following command: + +# tc qdisc add dev eth0 root handle 1: multiq + +The qdisc will allocate the number of bands to equal the number of queues that +the device reports, and bring the qdisc online. Assuming eth0 has 4 Tx +queues, the band mapping would look like: + +band 0 => queue 0 +band 1 => queue 1 +band 2 => queue 2 +band 3 => queue 3 + +Traffic will begin flowing through each queue based on either the simple_tx_hash +function or based on netdev->select_queue() if you have it defined. + +The behavior of tc filters remains the same. However a new tc action, +skbedit, has been added. Assuming you wanted to route all traffic to a +specific host, for example 192.168.0.3, through a specific queue you could use +this action and establish a filter such as: + +tc filter add dev eth0 parent 1: protocol ip prio 1 u32 \ + match ip dst 192.168.0.3 \ + action skbedit queue_mapping 3 + +Author: Alexander Duyck <alexander.h.duyck@intel.com> +Original Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com> diff --git a/Documentation/networking/phonet.txt b/Documentation/networking/phonet.txt new file mode 100644 index 0000000..0e6e592 --- /dev/null +++ b/Documentation/networking/phonet.txt @@ -0,0 +1,175 @@ +Linux Phonet protocol family +============================ + +Introduction +------------ + +Phonet is a packet protocol used by Nokia cellular modems for both IPC +and RPC. With the Linux Phonet socket family, Linux host processes can +receive and send messages from/to the modem, or any other external +device attached to the modem. The modem takes care of routing. + +Phonet packets can be exchanged through various hardware connections +depending on the device, such as: + - USB with the CDC Phonet interface, + - infrared, + - Bluetooth, + - an RS232 serial port (with a dedicated "FBUS" line discipline), + - the SSI bus with some TI OMAP processors. + + +Packets format +-------------- + +Phonet packets have a common header as follows: + + struct phonethdr { + uint8_t pn_media; /* Media type (link-layer identifier) */ + uint8_t pn_rdev; /* Receiver device ID */ + uint8_t pn_sdev; /* Sender device ID */ + uint8_t pn_res; /* Resource ID or function */ + uint16_t pn_length; /* Big-endian message byte length (minus 6) */ + uint8_t pn_robj; /* Receiver object ID */ + uint8_t pn_sobj; /* Sender object ID */ + }; + +On Linux, the link-layer header includes the pn_media byte (see below). +The next 7 bytes are part of the network-layer header. + +The device ID is split: the 6 higher-order bits consitute the device +address, while the 2 lower-order bits are used for multiplexing, as are +the 8-bit object identifiers. As such, Phonet can be considered as a +network layer with 6 bits of address space and 10 bits for transport +protocol (much like port numbers in IP world). + +The modem always has address number zero. All other device have a their +own 6-bit address. + + +Link layer +---------- + +Phonet links are always point-to-point links. The link layer header +consists of a single Phonet media type byte. It uniquely identifies the +link through which the packet is transmitted, from the modem's +perspective. Each Phonet network device shall prepend and set the media +type byte as appropriate. For convenience, a common phonet_header_ops +link-layer header operations structure is provided. It sets the +media type according to the network device hardware address. + +Linux Phonet network interfaces support a dedicated link layer packets +type (ETH_P_PHONET) which is out of the Ethernet type range. They can +only send and receive Phonet packets. + +The virtual TUN tunnel device driver can also be used for Phonet. This +requires IFF_TUN mode, _without_ the IFF_NO_PI flag. In this case, +there is no link-layer header, so there is no Phonet media type byte. + +Note that Phonet interfaces are not allowed to re-order packets, so +only the (default) Linux FIFO qdisc should be used with them. + + +Network layer +------------- + +The Phonet socket address family maps the Phonet packet header: + + struct sockaddr_pn { + sa_family_t spn_family; /* AF_PHONET */ + uint8_t spn_obj; /* Object ID */ + uint8_t spn_dev; /* Device ID */ + uint8_t spn_resource; /* Resource or function */ + uint8_t spn_zero[...]; /* Padding */ + }; + +The resource field is only used when sending and receiving; +It is ignored by bind() and getsockname(). + + +Low-level datagram protocol +--------------------------- + +Applications can send Phonet messages using the Phonet datagram socket +protocol from the PF_PHONET family. Each socket is bound to one of the +2^10 object IDs available, and can send and receive packets with any +other peer. + + struct sockaddr_pn addr = { .spn_family = AF_PHONET, }; + ssize_t len; + socklen_t addrlen = sizeof(addr); + int fd; + + fd = socket(PF_PHONET, SOCK_DGRAM, 0); + bind(fd, (struct sockaddr *)&addr, sizeof(addr)); + /* ... */ + + sendto(fd, msg, msglen, 0, (struct sockaddr *)&addr, sizeof(addr)); + len = recvfrom(fd, buf, sizeof(buf), 0, + (struct sockaddr *)&addr, &addrlen); + +This protocol follows the SOCK_DGRAM connection-less semantics. +However, connect() and getpeername() are not supported, as they did +not seem useful with Phonet usages (could be added easily). + + +Phonet Pipe protocol +-------------------- + +The Phonet Pipe protocol is a simple sequenced packets protocol +with end-to-end congestion control. It uses the passive listening +socket paradigm. The listening socket is bound to an unique free object +ID. Each listening socket can handle up to 255 simultaneous +connections, one per accept()'d socket. + + int lfd, cfd; + + lfd = socket(PF_PHONET, SOCK_SEQPACKET, PN_PROTO_PIPE); + listen (lfd, INT_MAX); + + /* ... */ + cfd = accept(lfd, NULL, NULL); + for (;;) + { + char buf[...]; + ssize_t len = read(cfd, buf, sizeof(buf)); + + /* ... */ + + write(cfd, msg, msglen); + } + +Connections are established between two endpoints by a "third party" +application. This means that both endpoints are passive; so connect() +is not possible. + +WARNING: +When polling a connected pipe socket for writability, there is an +intrinsic race condition whereby writability might be lost between the +polling and the writing system calls. In this case, the socket will +block until write because possible again, unless non-blocking mode +becomes enabled. + + +The pipe protocol provides two socket options at the SOL_PNPIPE level: + + PNPIPE_ENCAP accepts one integer value (int) of: + + PNPIPE_ENCAP_NONE: The socket operates normally (default). + + PNPIPE_ENCAP_IP: The socket is used as a backend for a virtual IP + interface. This requires CAP_NET_ADMIN capability. GPRS data + support on Nokia modems can use this. Note that the socket cannot + be reliably poll()'d or read() from while in this mode. + + PNPIPE_IFINDEX is a read-only integer value. It contains the + interface index of the network interface created by PNPIPE_ENCAP, + or zero if encapsulation is off. + + +Authors +------- + +Linux Phonet was initially written by Sakari Ailus. +Other contributors include Mikä Liljeberg, Andras Domokos, +Carlos Chinea and Rémi Denis-Courmont. +Copyright (C) 2008 Nokia Corporation. diff --git a/Documentation/networking/regulatory.txt b/Documentation/networking/regulatory.txt new file mode 100644 index 0000000..a96989a --- /dev/null +++ b/Documentation/networking/regulatory.txt @@ -0,0 +1,194 @@ +Linux wireless regulatory documentation +--------------------------------------- + +This document gives a brief review over how the Linux wireless +regulatory infrastructure works. + +More up to date information can be obtained at the project's web page: + +http://wireless.kernel.org/en/developers/Regulatory + +Keeping regulatory domains in userspace +--------------------------------------- + +Due to the dynamic nature of regulatory domains we keep them +in userspace and provide a framework for userspace to upload +to the kernel one regulatory domain to be used as the central +core regulatory domain all wireless devices should adhere to. + +How to get regulatory domains to the kernel +------------------------------------------- + +Userspace gets a regulatory domain in the kernel by having +a userspace agent build it and send it via nl80211. Only +expected regulatory domains will be respected by the kernel. + +A currently available userspace agent which can accomplish this +is CRDA - central regulatory domain agent. Its documented here: + +http://wireless.kernel.org/en/developers/Regulatory/CRDA + +Essentially the kernel will send a udev event when it knows +it needs a new regulatory domain. A udev rule can be put in place +to trigger crda to send the respective regulatory domain for a +specific ISO/IEC 3166 alpha2. + +Below is an example udev rule which can be used: + +# Example file, should be put in /etc/udev/rules.d/regulatory.rules +KERNEL=="regulatory*", ACTION=="change", SUBSYSTEM=="platform", RUN+="/sbin/crda" + +The alpha2 is passed as an environment variable under the variable COUNTRY. + +Who asks for regulatory domains? +-------------------------------- + +* Users + +Users can use iw: + +http://wireless.kernel.org/en/users/Documentation/iw + +An example: + + # set regulatory domain to "Costa Rica" + iw reg set CR + +This will request the kernel to set the regulatory domain to +the specificied alpha2. The kernel in turn will then ask userspace +to provide a regulatory domain for the alpha2 specified by the user +by sending a uevent. + +* Wireless subsystems for Country Information elements + +The kernel will send a uevent to inform userspace a new +regulatory domain is required. More on this to be added +as its integration is added. + +* Drivers + +If drivers determine they need a specific regulatory domain +set they can inform the wireless core using regulatory_hint(). +They have two options -- they either provide an alpha2 so that +crda can provide back a regulatory domain for that country or +they can build their own regulatory domain based on internal +custom knowledge so the wireless core can respect it. + +*Most* drivers will rely on the first mechanism of providing a +regulatory hint with an alpha2. For these drivers there is an additional +check that can be used to ensure compliance based on custom EEPROM +regulatory data. This additional check can be used by drivers by +registering on its struct wiphy a reg_notifier() callback. This notifier +is called when the core's regulatory domain has been changed. The driver +can use this to review the changes made and also review who made them +(driver, user, country IE) and determine what to allow based on its +internal EEPROM data. Devices drivers wishing to be capable of world +roaming should use this callback. More on world roaming will be +added to this document when its support is enabled. + +Device drivers who provide their own built regulatory domain +do not need a callback as the channels registered by them are +the only ones that will be allowed and therefore *additional* +cannels cannot be enabled. + +Example code - drivers hinting an alpha2: +------------------------------------------ + +This example comes from the zd1211rw device driver. You can start +by having a mapping of your device's EEPROM country/regulatory +domain value to to a specific alpha2 as follows: + +static struct zd_reg_alpha2_map reg_alpha2_map[] = { + { ZD_REGDOMAIN_FCC, "US" }, + { ZD_REGDOMAIN_IC, "CA" }, + { ZD_REGDOMAIN_ETSI, "DE" }, /* Generic ETSI, use most restrictive */ + { ZD_REGDOMAIN_JAPAN, "JP" }, + { ZD_REGDOMAIN_JAPAN_ADD, "JP" }, + { ZD_REGDOMAIN_SPAIN, "ES" }, + { ZD_REGDOMAIN_FRANCE, "FR" }, + +Then you can define a routine to map your read EEPROM value to an alpha2, +as follows: + +static int zd_reg2alpha2(u8 regdomain, char *alpha2) +{ + unsigned int i; + struct zd_reg_alpha2_map *reg_map; + for (i = 0; i < ARRAY_SIZE(reg_alpha2_map); i++) { + reg_map = ®_alpha2_map[i]; + if (regdomain == reg_map->reg) { + alpha2[0] = reg_map->alpha2[0]; + alpha2[1] = reg_map->alpha2[1]; + return 0; + } + } + return 1; +} + +Lastly, you can then hint to the core of your discovered alpha2, if a match +was found. You need to do this after you have registered your wiphy. You +are expected to do this during initialization. + + r = zd_reg2alpha2(mac->regdomain, alpha2); + if (!r) + regulatory_hint(hw->wiphy, alpha2, NULL); + +Example code - drivers providing a built in regulatory domain: +-------------------------------------------------------------- + +If you have regulatory information you can obtain from your +driver and you *need* to use this we let you build a regulatory domain +structure and pass it to the wireless core. To do this you should +kmalloc() a structure big enough to hold your regulatory domain +structure and you should then fill it with your data. Finally you simply +call regulatory_hint() with the regulatory domain structure in it. + +Bellow is a simple example, with a regulatory domain cached using the stack. +Your implementation may vary (read EEPROM cache instead, for example). + +Example cache of some regulatory domain + +struct ieee80211_regdomain mydriver_jp_regdom = { + .n_reg_rules = 3, + .alpha2 = "JP", + //.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), + /* IEEE 802.11a, channels 34..48 */ + REG_RULE(5170-20, 5240+20, 40, 6, 20, + NL80211_RRF_PASSIVE_SCAN), + /* IEEE 802.11a, channels 52..64 */ + REG_RULE(5260-20, 5320+20, 40, 6, 20, + NL80211_RRF_NO_IBSS | + NL80211_RRF_DFS), + } +}; + +Then in some part of your code after your wiphy has been registered: + + int r; + struct ieee80211_regdomain *rd; + int size_of_regd; + int num_rules = mydriver_jp_regdom.n_reg_rules; + unsigned int i; + + size_of_regd = sizeof(struct ieee80211_regdomain) + + (num_rules * sizeof(struct ieee80211_reg_rule)); + + rd = kzalloc(size_of_regd, GFP_KERNEL); + if (!rd) + return -ENOMEM; + + memcpy(rd, &mydriver_jp_regdom, sizeof(struct ieee80211_regdomain)); + + for (i=0; i < num_rules; i++) { + memcpy(&rd->reg_rules[i], &mydriver_jp_regdom.reg_rules[i], + sizeof(struct ieee80211_reg_rule)); + } + r = regulatory_hint(hw->wiphy, NULL, rd); + if (r) { + kfree(rd); + return r; + } + diff --git a/Documentation/networking/tproxy.txt b/Documentation/networking/tproxy.txt new file mode 100644 index 0000000..7b5996d --- /dev/null +++ b/Documentation/networking/tproxy.txt @@ -0,0 +1,85 @@ +Transparent proxy support +========================= + +This feature adds Linux 2.2-like transparent proxy support to current kernels. +To use it, enable NETFILTER_TPROXY, the socket match and the TPROXY target in +your kernel config. You will need policy routing too, so be sure to enable that +as well. + + +1. Making non-local sockets work +================================ + +The idea is that you identify packets with destination address matching a local +socket on your box, set the packet mark to a certain value, and then match on that +value using policy routing to have those packets delivered locally: + +# iptables -t mangle -N DIVERT +# iptables -t mangle -A PREROUTING -p tcp -m socket -j DIVERT +# iptables -t mangle -A DIVERT -j MARK --set-mark 1 +# iptables -t mangle -A DIVERT -j ACCEPT + +# ip rule add fwmark 1 lookup 100 +# ip route add local 0.0.0.0/0 dev lo table 100 + +Because of certain restrictions in the IPv4 routing output code you'll have to +modify your application to allow it to send datagrams _from_ non-local IP +addresses. All you have to do is enable the (SOL_IP, IP_TRANSPARENT) socket +option before calling bind: + +fd = socket(AF_INET, SOCK_STREAM, 0); +/* - 8< -*/ +int value = 1; +setsockopt(fd, SOL_IP, IP_TRANSPARENT, &value, sizeof(value)); +/* - 8< -*/ +name.sin_family = AF_INET; +name.sin_port = htons(0xCAFE); +name.sin_addr.s_addr = htonl(0xDEADBEEF); +bind(fd, &name, sizeof(name)); + +A trivial patch for netcat is available here: +http://people.netfilter.org/hidden/tproxy/netcat-ip_transparent-support.patch + + +2. Redirecting traffic +====================== + +Transparent proxying often involves "intercepting" traffic on a router. This is +usually done with the iptables REDIRECT target; however, there are serious +limitations of that method. One of the major issues is that it actually +modifies the packets to change the destination address -- which might not be +acceptable in certain situations. (Think of proxying UDP for example: you won't +be able to find out the original destination address. Even in case of TCP +getting the original destination address is racy.) + +The 'TPROXY' target provides similar functionality without relying on NAT. Simply +add rules like this to the iptables ruleset above: + +# iptables -t mangle -A PREROUTING -p tcp --dport 80 -j TPROXY \ + --tproxy-mark 0x1/0x1 --on-port 50080 + +Note that for this to work you'll have to modify the proxy to enable (SOL_IP, +IP_TRANSPARENT) for the listening socket. + + +3. Iptables extensions +====================== + +To use tproxy you'll need to have the 'socket' and 'TPROXY' modules +compiled for iptables. A patched version of iptables is available +here: http://git.balabit.hu/?p=bazsi/iptables-tproxy.git + + +4. Application support +====================== + +4.1. Squid +---------- + +Squid 3.HEAD has support built-in. To use it, pass +'--enable-linux-netfilter' to configure and set the 'tproxy' option on +the HTTP listener you redirect traffic to with the TPROXY iptables +target. + +For more information please consult the following page on the Squid +wiki: http://wiki.squid-cache.org/Features/Tproxy4 |