6 files changed, 593 insertions, 5 deletions

diff --git a/Documentation/networking/LICENSE.qlge b/Documentation/networking/LICENSE.qlge
new file mode 100644
index 000000000000..123b6edd7f18
--- /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 297ba7b1ccaf..2035bc4932f2 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 d391ea631141..4caa0e314cc2 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 000000000000..0e6e592f4f55
--- /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 000000000000..a96989a8ff35
--- /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 = &reg_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 000000000000..7b5996d9357e
--- /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