9 files changed, 1093 insertions, 118 deletions

diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 19b4c96b2a49..6da663607f7b 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -211,15 +211,6 @@ Who:   Adrian Bunk <bunk@stusta.de>
 
 ---------------------------
 
-What:   IPv4 only connection tracking/NAT/helpers
-When:   2.6.22
-Why:    The new layer 3 independant connection tracking replaces the old
-        IPv4 only version. After some stabilization of the new code the
-        old one will be removed.
-Who:    Patrick McHardy <kaber@trash.net>
-
----------------------------
-
 What:   ACPI hooks (X86_SPEEDSTEP_CENTRINO_ACPI) in speedstep-centrino driver
 When:   December 2006
 Why:    Speedstep-centrino driver with ACPI hooks and acpi-cpufreq driver are
@@ -294,18 +285,6 @@ Who:	Richard Purdie <rpurdie@rpsys.net>
 
 ---------------------------
 
-What:   Wireless extensions over netlink (CONFIG_NET_WIRELESS_RTNETLINK)
-When:   with the merge of wireless-dev, 2.6.22 or later
-Why:    The option/code is
-         * not enabled on most kernels
-         * not required by any userspace tools (except an experimental one,
-           and even there only for some parts, others use ioctl)
-         * pointless since wext is no longer evolving and the ioctl
-           interface needs to be kept
-Who:    Johannes Berg <johannes@sipsolutions.net>
-
----------------------------
-
 What:   i8xx_tco watchdog driver
 When:   in 2.6.22
 Why:    the i8xx_tco watchdog driver has been replaced by the iTCO_wdt
@@ -313,3 +292,22 @@ Why:	the i8xx_tco watchdog driver has been replaced by the iTCO_wdt
 Who:    Wim Van Sebroeck <wim@iguana.be>
 
 ---------------------------
+
+What:   Multipath cached routing support in ipv4
+When:   in 2.6.23
+Why:    Code was merged, then submitter immediately disappeared leaving
+        us with no maintainer and lots of bugs.  The code should not have
+        been merged in the first place, and many aspects of it's
+        implementation are blocking more critical core networking
+        development.  It's marked EXPERIMENTAL and no distribution
+        enables it because it cause obscure crashes due to unfixable bugs
+        (interfaces don't return errors so memory allocation can't be
+        handled, calling contexts of these interfaces make handling
+        errors impossible too because they get called after we've
+        totally commited to creating a route object, for example).
+        This problem has existed for years and no forward progress
+        has ever been made, and nobody steps up to try and salvage
+        this code, so we're going to finally just get rid of it.
+Who:    David S. Miller <davem@davemloft.net>
+
+---------------------------
diff --git a/Documentation/filesystems/afs.txt b/Documentation/filesystems/afs.txt
index 2f4237dfb8c7..12ad6c7f4e50 100644
--- a/Documentation/filesystems/afs.txt
+++ b/Documentation/filesystems/afs.txt
@@ -1,31 +1,82 @@
+                             ====================
                              kAFS: AFS FILESYSTEM
                              ====================
 
-ABOUT
-=====
+Contents:
+
+ - Overview.
+ - Usage.
+ - Mountpoints.
+ - Proc filesystem.
+ - The cell database.
+ - Security.
+ - Examples.
+
+
+========
+OVERVIEW
+========
 
-This filesystem provides a fairly simple AFS filesystem driver. It is under
-development and only provides very basic facilities. It does not yet support
-the following AFS features:
+This filesystem provides a fairly simple secure AFS filesystem driver. It is
+under development and does not yet provide the full feature set.  The features
+it does support include:
 
-        (*) Write support.
-        (*) Communications security.
-        (*) Local caching.
-        (*) pioctl() system call.
-        (*) Automatic mounting of embedded mountpoints.
+ (*) Security (currently only AFS kaserver and KerberosIV tickets).
 
+ (*) File reading.
 
+ (*) Automounting.
+
+It does not yet support the following AFS features:
+
+ (*) Write support.
+
+ (*) Local caching.
+
+ (*) pioctl() system call.
+
+
+===========
+COMPILATION
+===========
+
+The filesystem should be enabled by turning on the kernel configuration
+options:
+
+        CONFIG_AF_RXRPC         - The RxRPC protocol transport
+        CONFIG_RXKAD            - The RxRPC Kerberos security handler
+        CONFIG_AFS              - The AFS filesystem
+
+Additionally, the following can be turned on to aid debugging:
+
+        CONFIG_AF_RXRPC_DEBUG   - Permit AF_RXRPC debugging to be enabled
+        CONFIG_AFS_DEBUG        - Permit AFS debugging to be enabled
+
+They permit the debugging messages to be turned on dynamically by manipulating
+the masks in the following files:
+
+        /sys/module/af_rxrpc/parameters/debug
+        /sys/module/afs/parameters/debug
+
+
+=====
 USAGE
 =====
 
 When inserting the driver modules the root cell must be specified along with a
 list of volume location server IP addresses:
 
-        insmod rxrpc.o
+        insmod af_rxrpc.o
+        insmod rxkad.o
         insmod kafs.o rootcell=cambridge.redhat.com:172.16.18.73:172.16.18.91
 
-The first module is a driver for the RxRPC remote operation protocol, and the
-second is the actual filesystem driver for the AFS filesystem.
+The first module is the AF_RXRPC network protocol driver.  This provides the
+RxRPC remote operation protocol and may also be accessed from userspace.  See:
+
+        Documentation/networking/rxrpc.txt
+
+The second module is the kerberos RxRPC security driver, and the third module
+is the actual filesystem driver for the AFS filesystem.
 
 Once the module has been loaded, more modules can be added by the following
 procedure:
@@ -33,7 +84,7 @@ procedure:
         echo add grand.central.org 18.7.14.88:128.2.191.224 >/proc/fs/afs/cells
 
 Where the parameters to the "add" command are the name of a cell and a list of
-volume location servers within that cell.
+volume location servers within that cell, with the latter separated by colons.
 
 Filesystems can be mounted anywhere by commands similar to the following:
 
@@ -42,11 +93,6 @@ Filesystems can be mounted anywhere by commands similar to the following:
         mount -t afs "#root.afs." /afs
         mount -t afs "#root.cell." /afs/cambridge
 
-  NB: When using this on Linux 2.4, the mount command has to be different,
-      since the filesystem doesn't have access to the device name argument:
-
-        mount -t afs none /afs -ovol="#root.afs."
-
 Where the initial character is either a hash or a percent symbol depending on
 whether you definitely want a R/W volume (hash) or whether you'd prefer a R/O
 volume, but are willing to use a R/W volume instead (percent).
@@ -60,55 +106,66 @@ named volume will be looked up in the cell specified during insmod.
 Additional cells can be added through /proc (see later section).
 
 
+===========
 MOUNTPOINTS
 ===========
 
-AFS has a concept of mountpoints. These are specially formatted symbolic links
-(of the same form as the "device name" passed to mount). kAFS presents these
-to the user as directories that have special properties:
+AFS has a concept of mountpoints. In AFS terms, these are specially formatted
+symbolic links (of the same form as the "device name" passed to mount).  kAFS
+presents these to the user as directories that have a follow-link capability
+(ie: symbolic link semantics).  If anyone attempts to access them, they will
+automatically cause the target volume to be mounted (if possible) on that site.
 
-  (*) They cannot be listed. Running a program like "ls" on them will incur an
-      EREMOTE error (Object is remote).
+Automatically mounted filesystems will be automatically unmounted approximately
+twenty minutes after they were last used.  Alternatively they can be unmounted
+directly with the umount() system call.
 
-  (*) Other objects can't be looked up inside of them. This also incurs an
-      EREMOTE error.
+Manually unmounting an AFS volume will cause any idle submounts upon it to be
+culled first.  If all are culled, then the requested volume will also be
+unmounted, otherwise error EBUSY will be returned.
 
-  (*) They can be queried with the readlink() system call, which will return
-      the name of the mountpoint to which they point. The "readlink" program
-      will also work.
+This can be used by the administrator to attempt to unmount the whole AFS tree
+mounted on /afs in one go by doing:
 
-  (*) They can be mounted on (which symbolic links can't).
+        umount /afs
 
 
+===============
 PROC FILESYSTEM
 ===============
 
-The rxrpc module creates a number of files in various places in the /proc
-filesystem:
-
-  (*) Firstly, some information files are made available in a directory called
-      "/proc/net/rxrpc/". These list the extant transport endpoint, peer,
-      connection and call records.
-
-  (*) Secondly, some control files are made available in a directory called
-      "/proc/sys/rxrpc/". Currently, all these files can be used for is to
-      turn on various levels of tracing.
-
 The AFS modules creates a "/proc/fs/afs/" directory and populates it:
 
-  (*) A "cells" file that lists cells currently known to the afs module.
+  (*) A "cells" file that lists cells currently known to the afs module and
+      their usage counts:
+
+        [root@andromeda ~]# cat /proc/fs/afs/cells
+        USE NAME
+          3 cambridge.redhat.com
 
   (*) A directory per cell that contains files that list volume location
       servers, volumes, and active servers known within that cell.
 
+        [root@andromeda ~]# cat /proc/fs/afs/cambridge.redhat.com/servers
+        USE ADDR            STATE
+          4 172.16.18.91        0
+        [root@andromeda ~]# cat /proc/fs/afs/cambridge.redhat.com/vlservers
+        ADDRESS
+        172.16.18.91
+        [root@andromeda ~]# cat /proc/fs/afs/cambridge.redhat.com/volumes
+        USE STT VLID[0]  VLID[1]  VLID[2]  NAME
+          1 Val 20000000 20000001 20000002 root.afs
 
+
+=================
 THE CELL DATABASE
 =================
 
-The filesystem maintains an internal database of all the cells it knows and
-the IP addresses of the volume location servers for those cells. The cell to
-which the computer belongs is added to the database when insmod is performed
-by the "rootcell=" argument.
+The filesystem maintains an internal database of all the cells it knows and the
+IP addresses of the volume location servers for those cells.  The cell to which
+the system belongs is added to the database when insmod is performed by the
+"rootcell=" argument or, if compiled in, using a "kafs.rootcell=" argument on
+the kernel command line.
 
 Further cells can be added by commands similar to the following:
 
@@ -118,20 +175,65 @@ Further cells can be added by commands similar to the following:
 No other cell database operations are available at this time.
 
 
+========
+SECURITY
+========
+
+Secure operations are initiated by acquiring a key using the klog program.  A
+very primitive klog program is available at:
+
+        http://people.redhat.com/~dhowells/rxrpc/klog.c
+
+This should be compiled by:
+
+        make klog LDLIBS="-lcrypto -lcrypt -lkrb4 -lkeyutils"
+
+And then run as:
+
+        ./klog
+
+Assuming it's successful, this adds a key of type RxRPC, named for the service
+and cell, eg: "afs@<cellname>".  This can be viewed with the keyctl program or
+by cat'ing /proc/keys:
+
+        [root@andromeda ~]# keyctl show
+        Session Keyring
+               -3 --alswrv      0     0  keyring: _ses.3268
+                2 --alswrv      0     0   \_ keyring: _uid.0
+        111416553 --als--v      0     0   \_ rxrpc: afs@CAMBRIDGE.REDHAT.COM
+
+Currently the username, realm, password and proposed ticket lifetime are
+compiled in to the program.
+
+It is not required to acquire a key before using AFS facilities, but if one is
+not acquired then all operations will be governed by the anonymous user parts
+of the ACLs.
+
+If a key is acquired, then all AFS operations, including mounts and automounts,
+made by a possessor of that key will be secured with that key.
+
+If a file is opened with a particular key and then the file descriptor is
+passed to a process that doesn't have that key (perhaps over an AF_UNIX
+socket), then the operations on the file will be made with key that was used to
+open the file.
+
+
+========
 EXAMPLES
 ========
 
-Here's what I use to test this. Some of the names and IP addresses are local
-to my internal DNS. My "root.afs" partition has a mount point within it for
+Here's what I use to test this.  Some of the names and IP addresses are local
+to my internal DNS.  My "root.afs" partition has a mount point within it for
 some public volumes volumes.
 
-insmod -S /tmp/rxrpc.o 
-insmod -S /tmp/kafs.o rootcell=cambridge.redhat.com:172.16.18.73:172.16.18.91
+insmod /tmp/rxrpc.o
+insmod /tmp/rxkad.o
+insmod /tmp/kafs.o rootcell=cambridge.redhat.com:172.16.18.91
 
 mount -t afs \%root.afs. /afs
 mount -t afs \%cambridge.redhat.com:root.cell. /afs/cambridge.redhat.com/
 
-echo add grand.central.org 18.7.14.88:128.2.191.224 > /proc/fs/afs/cells 
+echo add grand.central.org 18.7.14.88:128.2.191.224 > /proc/fs/afs/cells
 mount -t afs "#grand.central.org:root.cell." /afs/grand.central.org/
 mount -t afs "#grand.central.org:root.archive." /afs/grand.central.org/archive
 mount -t afs "#grand.central.org:root.contrib." /afs/grand.central.org/contrib
@@ -141,15 +243,7 @@ mount -t afs "#grand.central.org:root.service." /afs/grand.central.org/service
 mount -t afs "#grand.central.org:root.software." /afs/grand.central.org/software
 mount -t afs "#grand.central.org:root.user." /afs/grand.central.org/user
 
-umount /afs/grand.central.org/user
-umount /afs/grand.central.org/software
-umount /afs/grand.central.org/service
-umount /afs/grand.central.org/project
-umount /afs/grand.central.org/doc
-umount /afs/grand.central.org/contrib
-umount /afs/grand.central.org/archive
-umount /afs/grand.central.org
-umount /afs/cambridge.redhat.com
 umount /afs
 rmmod kafs
+rmmod rxkad
 rmmod rxrpc
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 5484ab5efd4f..7aaf09b86a55 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1421,6 +1421,15 @@ fewer messages that will be written. Message_burst controls when messages will
 be dropped.  The  default  settings  limit  warning messages to one every five
 seconds.
 
+warnings
+--------
+
+This controls console messages from the networking stack that can occur because
+of problems on the network like duplicate address or bad checksums. Normally,
+this should be enabled, but if the problem persists the messages can be
+disabled.
+
+
 netdev_max_backlog
 ------------------
 
diff --git a/Documentation/keys.txt b/Documentation/keys.txt
index 60c665d9cfaa..81d9aa097298 100644
--- a/Documentation/keys.txt
+++ b/Documentation/keys.txt
@@ -859,6 +859,18 @@ payload contents" for more information.
         void unregister_key_type(struct key_type *type);
 
 
+Under some circumstances, it may be desirable to desirable to deal with a
+bundle of keys.  The facility provides access to the keyring type for managing
+such a bundle:
+
+        struct key_type key_type_keyring;
+
+This can be used with a function such as request_key() to find a specific
+keyring in a process's keyrings.  A keyring thus found can then be searched
+with keyring_search().  Note that it is not possible to use request_key() to
+search a specific keyring, so using keyrings in this way is of limited utility.
+
+
 ===================================
 NOTES ON ACCESSING PAYLOAD CONTENTS
 ===================================
diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index de809e58092f..1da566630831 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -920,40 +920,9 @@ options, you may wish to use the "max_bonds" module parameter,
 documented above.
 
         To create multiple bonding devices with differing options, it
-is necessary to load the bonding driver multiple times.  Note that
-current versions of the sysconfig network initialization scripts
-handle this automatically; if your distro uses these scripts, no
-special action is needed.  See the section Configuring Bonding
-Devices, above, if you're not sure about your network initialization
-scripts.
-
-        To load multiple instances of the module, it is necessary to
-specify a different name for each instance (the module loading system
-requires that every loaded module, even multiple instances of the same
-module, have a unique name).  This is accomplished by supplying
-multiple sets of bonding options in /etc/modprobe.conf, for example:
-        
-alias bond0 bonding
-options bond0 -o bond0 mode=balance-rr miimon=100
-
-alias bond1 bonding
-options bond1 -o bond1 mode=balance-alb miimon=50
-
-        will load the bonding module two times.  The first instance is
-named "bond0" and creates the bond0 device in balance-rr mode with an
-miimon of 100.  The second instance is named "bond1" and creates the
-bond1 device in balance-alb mode with an miimon of 50.
-
-        In some circumstances (typically with older distributions),
-the above does not work, and the second bonding instance never sees
-its options.  In that case, the second options line can be substituted
-as follows:
-
-install bond1 /sbin/modprobe --ignore-install bonding -o bond1 \
-        mode=balance-alb miimon=50
+is necessary to use bonding parameters exported by sysfs, documented
+in the section below.
 
-        This may be repeated any number of times, specifying a new and
-unique name in place of bond1 for each subsequent instance.
 
 3.4 Configuring Bonding Manually via Sysfs
 ------------------------------------------
diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index 387482e46c47..4504cc59e405 100644
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -57,6 +57,16 @@ DCCP_SOCKOPT_SEND_CSCOV is for the receiver and has a different meaning: it
         coverage value are also acceptable. The higher the number, the more
         restrictive this setting (see [RFC 4340, sec. 9.2.1]).
 
+The following two options apply to CCID 3 exclusively and are getsockopt()-only.
+In either case, a TFRC info struct (defined in <linux/tfrc.h>) is returned.
+DCCP_SOCKOPT_CCID_RX_INFO
+        Returns a `struct tfrc_rx_info' in optval; the buffer for optval and
+        optlen must be set to at least sizeof(struct tfrc_rx_info).
+DCCP_SOCKOPT_CCID_TX_INFO
+        Returns a `struct tfrc_tx_info' in optval; the buffer for optval and
+        optlen must be set to at least sizeof(struct tfrc_tx_info).
+
+
 Sysctl variables
 ================
 Several DCCP default parameters can be managed by the following sysctls
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 702d1d8dd04a..af6a63ab9026 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -179,11 +179,31 @@ tcp_fin_timeout - INTEGER
         because they eat maximum 1.5K of memory, but they tend
         to live longer. Cf. tcp_max_orphans.
 
-tcp_frto - BOOLEAN
+tcp_frto - INTEGER
         Enables F-RTO, an enhanced recovery algorithm for TCP retransmission
         timeouts.  It is particularly beneficial in wireless environments
         where packet loss is typically due to random radio interference
-        rather than intermediate router congestion.
+        rather than intermediate router congestion. If set to 1, basic
+        version is enabled. 2 enables SACK enhanced F-RTO, which is
+        EXPERIMENTAL. The basic version can be used also when SACK is
+        enabled for a flow through tcp_sack sysctl.
+
+tcp_frto_response - INTEGER
+        When F-RTO has detected that a TCP retransmission timeout was
+        spurious (i.e, the timeout would have been avoided had TCP set a
+        longer retransmission timeout), TCP has several options what to do
+        next. Possible values are:
+                0 Rate halving based; a smooth and conservative response,
+                  results in halved cwnd and ssthresh after one RTT
+                1 Very conservative response; not recommended because even
+                  though being valid, it interacts poorly with the rest of
+                  Linux TCP, halves cwnd and ssthresh immediately
+                2 Aggressive response; undoes congestion control measures
+                  that are now known to be unnecessary (ignoring the
+                  possibility of a lost retransmission that would require
+                  TCP to be more cautious), cwnd and ssthresh are restored
+                  to the values prior timeout
+        Default: 0 (rate halving based)
 
 tcp_keepalive_time - INTEGER
         How often TCP sends out keepalive messages when keepalive is enabled.
@@ -995,7 +1015,12 @@ bridge-nf-call-ip6tables - BOOLEAN
         Default: 1
 
 bridge-nf-filter-vlan-tagged - BOOLEAN
-        1 : pass bridged vlan-tagged ARP/IP traffic to arptables/iptables.
+        1 : pass bridged vlan-tagged ARP/IP/IPv6 traffic to {arp,ip,ip6}tables.
+        0 : disable this.
+        Default: 1
+
+bridge-nf-filter-pppoe-tagged - BOOLEAN
+        1 : pass bridged pppoe-tagged IP/IPv6 traffic to {ip,ip6}tables.
         0 : disable this.
         Default: 1
 
diff --git a/Documentation/networking/rxrpc.txt b/Documentation/networking/rxrpc.txt
new file mode 100644
index 000000000000..cae231b1c134
--- /dev/null
+++ b/Documentation/networking/rxrpc.txt
@@ -0,0 +1,859 @@
+                            ======================
+                            RxRPC NETWORK PROTOCOL
+                            ======================
+
+The RxRPC protocol driver provides a reliable two-phase transport on top of UDP
+that can be used to perform RxRPC remote operations.  This is done over sockets
+of AF_RXRPC family, using sendmsg() and recvmsg() with control data to send and
+receive data, aborts and errors.
+
+Contents of this document:
+
+ (*) Overview.
+
+ (*) RxRPC protocol summary.
+
+ (*) AF_RXRPC driver model.
+
+ (*) Control messages.
+
+ (*) Socket options.
+
+ (*) Security.
+
+ (*) Example client usage.
+
+ (*) Example server usage.
+
+ (*) AF_RXRPC kernel interface.
+
+
+========
+OVERVIEW
+========
+
+RxRPC is a two-layer protocol.  There is a session layer which provides
+reliable virtual connections using UDP over IPv4 (or IPv6) as the transport
+layer, but implements a real network protocol; and there's the presentation
+layer which renders structured data to binary blobs and back again using XDR
+(as does SunRPC):
+
+                +-------------+
+                | Application |
+                +-------------+
+                |     XDR     |         Presentation
+                +-------------+
+                |    RxRPC    |         Session
+                +-------------+
+                |     UDP     |         Transport
+                +-------------+
+
+
+AF_RXRPC provides:
+
+ (1) Part of an RxRPC facility for both kernel and userspace applications by
+     making the session part of it a Linux network protocol (AF_RXRPC).
+
+ (2) A two-phase protocol.  The client transmits a blob (the request) and then
+     receives a blob (the reply), and the server receives the request and then
+     transmits the reply.
+
+ (3) Retention of the reusable bits of the transport system set up for one call
+     to speed up subsequent calls.
+
+ (4) A secure protocol, using the Linux kernel's key retention facility to
+     manage security on the client end.  The server end must of necessity be
+     more active in security negotiations.
+
+AF_RXRPC does not provide XDR marshalling/presentation facilities.  That is
+left to the application.  AF_RXRPC only deals in blobs.  Even the operation ID
+is just the first four bytes of the request blob, and as such is beyond the
+kernel's interest.
+
+
+Sockets of AF_RXRPC family are:
+
+ (1) created as type SOCK_DGRAM;
+
+ (2) provided with a protocol of the type of underlying transport they're going
+     to use - currently only PF_INET is supported.
+
+
+The Andrew File System (AFS) is an example of an application that uses this and
+that has both kernel (filesystem) and userspace (utility) components.
+
+
+======================
+RXRPC PROTOCOL SUMMARY
+======================
+
+An overview of the RxRPC protocol:
+
+ (*) RxRPC sits on top of another networking protocol (UDP is the only option
+     currently), and uses this to provide network transport.  UDP ports, for
+     example, provide transport endpoints.
+
+ (*) RxRPC supports multiple virtual "connections" from any given transport
+     endpoint, thus allowing the endpoints to be shared, even to the same
+     remote endpoint.
+
+ (*) Each connection goes to a particular "service".  A connection may not go
+     to multiple services.  A service may be considered the RxRPC equivalent of
+     a port number.  AF_RXRPC permits multiple services to share an endpoint.
+
+ (*) Client-originating packets are marked, thus a transport endpoint can be
+     shared between client and server connections (connections have a
+     direction).
+
+ (*) Up to a billion connections may be supported concurrently between one
+     local transport endpoint and one service on one remote endpoint.  An RxRPC
+     connection is described by seven numbers:
+
+        Local address   }
+        Local port      } Transport (UDP) address
+        Remote address  }
+        Remote port     }
+        Direction
+        Connection ID
+        Service ID
+
+ (*) Each RxRPC operation is a "call".  A connection may make up to four
+     billion calls, but only up to four calls may be in progress on a
+     connection at any one time.
+
+ (*) Calls are two-phase and asymmetric: the client sends its request data,
+     which the service receives; then the service transmits the reply data
+     which the client receives.
+
+ (*) The data blobs are of indefinite size, the end of a phase is marked with a
+     flag in the packet.  The number of packets of data making up one blob may
+     not exceed 4 billion, however, as this would cause the sequence number to
+     wrap.
+
+ (*) The first four bytes of the request data are the service operation ID.
+
+ (*) Security is negotiated on a per-connection basis.  The connection is
+     initiated by the first data packet on it arriving.  If security is
+     requested, the server then issues a "challenge" and then the client
+     replies with a "response".  If the response is successful, the security is
+     set for the lifetime of that connection, and all subsequent calls made
+     upon it use that same security.  In the event that the server lets a
+     connection lapse before the client, the security will be renegotiated if
+     the client uses the connection again.
+
+ (*) Calls use ACK packets to handle reliability.  Data packets are also
+     explicitly sequenced per call.
+
+ (*) There are two types of positive acknowledgement: hard-ACKs and soft-ACKs.
+     A hard-ACK indicates to the far side that all the data received to a point
+     has been received and processed; a soft-ACK indicates that the data has
+     been received but may yet be discarded and re-requested.  The sender may
+     not discard any transmittable packets until they've been hard-ACK'd.
+
+ (*) Reception of a reply data packet implicitly hard-ACK's all the data
+     packets that make up the request.
+
+ (*) An call is complete when the request has been sent, the reply has been
+     received and the final hard-ACK on the last packet of the reply has
+     reached the server.
+
+ (*) An call may be aborted by either end at any time up to its completion.
+
+
+=====================
+AF_RXRPC DRIVER MODEL
+=====================
+
+About the AF_RXRPC driver:
+
+ (*) The AF_RXRPC protocol transparently uses internal sockets of the transport
+     protocol to represent transport endpoints.
+
+ (*) AF_RXRPC sockets map onto RxRPC connection bundles.  Actual RxRPC
+     connections are handled transparently.  One client socket may be used to
+     make multiple simultaneous calls to the same service.  One server socket
+     may handle calls from many clients.
+
+ (*) Additional parallel client connections will be initiated to support extra
+     concurrent calls, up to a tunable limit.
+
+ (*) Each connection is retained for a certain amount of time [tunable] after
+     the last call currently using it has completed in case a new call is made
+     that could reuse it.
+
+ (*) Each internal UDP socket is retained [tunable] for a certain amount of
+     time [tunable] after the last connection using it discarded, in case a new
+     connection is made that could use it.
+
+ (*) A client-side connection is only shared between calls if they have have
+     the same key struct describing their security (and assuming the calls
+     would otherwise share the connection).  Non-secured calls would also be
+     able to share connections with each other.
+
+ (*) A server-side connection is shared if the client says it is.
+
+ (*) ACK'ing is handled by the protocol driver automatically, including ping
+     replying.
+
+ (*) SO_KEEPALIVE automatically pings the other side to keep the connection
+     alive [TODO].
+
+ (*) If an ICMP error is received, all calls affected by that error will be
+     aborted with an appropriate network error passed through recvmsg().
+
+
+Interaction with the user of the RxRPC socket:
+
+ (*) A socket is made into a server socket by binding an address with a
+     non-zero service ID.
+
+ (*) In the client, sending a request is achieved with one or more sendmsgs,
+     followed by the reply being received with one or more recvmsgs.
+
+ (*) The first sendmsg for a request to be sent from a client contains a tag to
+     be used in all other sendmsgs or recvmsgs associated with that call.  The
+     tag is carried in the control data.
+
+ (*) connect() is used to supply a default destination address for a client
+     socket.  This may be overridden by supplying an alternate address to the
+     first sendmsg() of a call (struct msghdr::msg_name).
+
+ (*) If connect() is called on an unbound client, a random local port will
+     bound before the operation takes place.
+
+ (*) A server socket may also be used to make client calls.  To do this, the
+     first sendmsg() of the call must specify the target address.  The server's
+     transport endpoint is used to send the packets.
+
+ (*) Once the application has received the last message associated with a call,
+     the tag is guaranteed not to be seen again, and so it can be used to pin
+     client resources.  A new call can then be initiated with the same tag
+     without fear of interference.
+
+ (*) In the server, a request is received with one or more recvmsgs, then the
+     the reply is transmitted with one or more sendmsgs, and then the final ACK
+     is received with a last recvmsg.
+
+ (*) When sending data for a call, sendmsg is given MSG_MORE if there's more
+     data to come on that call.
+
+ (*) When receiving data for a call, recvmsg flags MSG_MORE if there's more
+     data to come for that call.
+
+ (*) When receiving data or messages for a call, MSG_EOR is flagged by recvmsg
+     to indicate the terminal message for that call.
+
+ (*) A call may be aborted by adding an abort control message to the control
+     data.  Issuing an abort terminates the kernel's use of that call's tag.
+     Any messages waiting in the receive queue for that call will be discarded.
+
+ (*) Aborts, busy notifications and challenge packets are delivered by recvmsg,
+     and control data messages will be set to indicate the context.  Receiving
+     an abort or a busy message terminates the kernel's use of that call's tag.
+
+ (*) The control data part of the msghdr struct is used for a number of things:
+
+     (*) The tag of the intended or affected call.
+
+     (*) Sending or receiving errors, aborts and busy notifications.
+
+     (*) Notifications of incoming calls.
+
+     (*) Sending debug requests and receiving debug replies [TODO].
+
+ (*) When the kernel has received and set up an incoming call, it sends a
+     message to server application to let it know there's a new call awaiting
+     its acceptance [recvmsg reports a special control message].  The server
+     application then uses sendmsg to assign a tag to the new call.  Once that
+     is done, the first part of the request data will be delivered by recvmsg.
+
+ (*) The server application has to provide the server socket with a keyring of
+     secret keys corresponding to the security types it permits.  When a secure
+     connection is being set up, the kernel looks up the appropriate secret key
+     in the keyring and then sends a challenge packet to the client and
+     receives a response packet.  The kernel then checks the authorisation of
+     the packet and either aborts the connection or sets up the security.
+
+ (*) The name of the key a client will use to secure its communications is
+     nominated by a socket option.
+
+
+Notes on recvmsg:
+
+ (*) If there's a sequence of data messages belonging to a particular call on
+     the receive queue, then recvmsg will keep working through them until:
+
+     (a) it meets the end of that call's received data,
+
+     (b) it meets a non-data message,
+
+     (c) it meets a message belonging to a different call, or
+
+     (d) it fills the user buffer.
+
+     If recvmsg is called in blocking mode, it will keep sleeping, awaiting the
+     reception of further data, until one of the above four conditions is met.
+
+ (2) MSG_PEEK operates similarly, but will return immediately if it has put any
+     data in the buffer rather than sleeping until it can fill the buffer.
+
+ (3) If a data message is only partially consumed in filling a user buffer,
+     then the remainder of that message will be left on the front of the queue
+     for the next taker.  MSG_TRUNC will never be flagged.
+
+ (4) If there is more data to be had on a call (it hasn't copied the last byte
+     of the last data message in that phase yet), then MSG_MORE will be
+     flagged.
+
+
+================
+CONTROL MESSAGES
+================
+
+AF_RXRPC makes use of control messages in sendmsg() and recvmsg() to multiplex
+calls, to invoke certain actions and to report certain conditions.  These are:
+
+        MESSAGE ID              SRT DATA        MEANING
+        ======================= === =========== ===============================
+        RXRPC_USER_CALL_ID      sr- User ID     App's call specifier
+        RXRPC_ABORT             srt Abort code  Abort code to issue/received
+        RXRPC_ACK               -rt n/a         Final ACK received
+        RXRPC_NET_ERROR         -rt error num   Network error on call
+        RXRPC_BUSY              -rt n/a         Call rejected (server busy)
+        RXRPC_LOCAL_ERROR       -rt error num   Local error encountered
+        RXRPC_NEW_CALL          -r- n/a         New call received
+        RXRPC_ACCEPT            s-- n/a         Accept new call
+
+        (SRT = usable in Sendmsg / delivered by Recvmsg / Terminal message)
+
+ (*) RXRPC_USER_CALL_ID
+
+     This is used to indicate the application's call ID.  It's an unsigned long
+     that the app specifies in the client by attaching it to the first data
+     message or in the server by passing it in association with an RXRPC_ACCEPT
+     message.  recvmsg() passes it in conjunction with all messages except
+     those of the RXRPC_NEW_CALL message.
+
+ (*) RXRPC_ABORT
+
+     This is can be used by an application to abort a call by passing it to
+     sendmsg, or it can be delivered by recvmsg to indicate a remote abort was
+     received.  Either way, it must be associated with an RXRPC_USER_CALL_ID to
+     specify the call affected.  If an abort is being sent, then error EBADSLT
+     will be returned if there is no call with that user ID.
+
+ (*) RXRPC_ACK
+
+     This is delivered to a server application to indicate that the final ACK
+     of a call was received from the client.  It will be associated with an
+     RXRPC_USER_CALL_ID to indicate the call that's now complete.
+
+ (*) RXRPC_NET_ERROR
+
+     This is delivered to an application to indicate that an ICMP error message
+     was encountered in the process of trying to talk to the peer.  An
+     errno-class integer value will be included in the control message data
+     indicating the problem, and an RXRPC_USER_CALL_ID will indicate the call
+     affected.
+
+ (*) RXRPC_BUSY
+
+     This is delivered to a client application to indicate that a call was
+     rejected by the server due to the server being busy.  It will be
+     associated with an RXRPC_USER_CALL_ID to indicate the rejected call.
+
+ (*) RXRPC_LOCAL_ERROR
+
+     This is delivered to an application to indicate that a local error was
+     encountered and that a call has been aborted because of it.  An
+     errno-class integer value will be included in the control message data
+     indicating the problem, and an RXRPC_USER_CALL_ID will indicate the call
+     affected.
+
+ (*) RXRPC_NEW_CALL
+
+     This is delivered to indicate to a server application that a new call has
+     arrived and is awaiting acceptance.  No user ID is associated with this,
+     as a user ID must subsequently be assigned by doing an RXRPC_ACCEPT.
+
+ (*) RXRPC_ACCEPT
+
+     This is used by a server application to attempt to accept a call and
+     assign it a user ID.  It should be associated with an RXRPC_USER_CALL_ID
+     to indicate the user ID to be assigned.  If there is no call to be
+     accepted (it may have timed out, been aborted, etc.), then sendmsg will
+     return error ENODATA.  If the user ID is already in use by another call,
+     then error EBADSLT will be returned.
+
+
+==============
+SOCKET OPTIONS
+==============
+
+AF_RXRPC sockets support a few socket options at the SOL_RXRPC level:
+
+ (*) RXRPC_SECURITY_KEY
+
+     This is used to specify the description of the key to be used.  The key is
+     extracted from the calling process's keyrings with request_key() and
+     should be of "rxrpc" type.
+
+     The optval pointer points to the description string, and optlen indicates
+     how long the string is, without the NUL terminator.
+
+ (*) RXRPC_SECURITY_KEYRING
+
+     Similar to above but specifies a keyring of server secret keys to use (key
+     type "keyring").  See the "Security" section.
+
+ (*) RXRPC_EXCLUSIVE_CONNECTION
+
+     This is used to request that new connections should be used for each call
+     made subsequently on this socket.  optval should be NULL and optlen 0.
+
+ (*) RXRPC_MIN_SECURITY_LEVEL
+
+     This is used to specify the minimum security level required for calls on
+     this socket.  optval must point to an int containing one of the following
+     values:
+
+     (a) RXRPC_SECURITY_PLAIN
+
+         Encrypted checksum only.
+
+     (b) RXRPC_SECURITY_AUTH
+
+         Encrypted checksum plus packet padded and first eight bytes of packet
+         encrypted - which includes the actual packet length.
+
+     (c) RXRPC_SECURITY_ENCRYPTED
+
+         Encrypted checksum plus entire packet padded and encrypted, including
+         actual packet length.
+
+
+========
+SECURITY
+========
+
+Currently, only the kerberos 4 equivalent protocol has been implemented
+(security index 2 - rxkad).  This requires the rxkad module to be loaded and,
+on the client, tickets of the appropriate type to be obtained from the AFS
+kaserver or the kerberos server and installed as "rxrpc" type keys.  This is
+normally done using the klog program.  An example simple klog program can be
+found at:
+
+        http://people.redhat.com/~dhowells/rxrpc/klog.c
+
+The payload provided to add_key() on the client should be of the following
+form:
+
+        struct rxrpc_key_sec2_v1 {
+                uint16_t        security_index; /* 2 */
+                uint16_t        ticket_length;  /* length of ticket[] */
+                uint32_t        expiry;         /* time at which expires */
+                uint8_t         kvno;           /* key version number */
+                uint8_t         __pad[3];
+                uint8_t         session_key[8]; /* DES session key */
+                uint8_t         ticket[0];      /* the encrypted ticket */
+        };
+
+Where the ticket blob is just appended to the above structure.
+
+
+For the server, keys of type "rxrpc_s" must be made available to the server.
+They have a description of "<serviceID>:<securityIndex>" (eg: "52:2" for an
+rxkad key for the AFS VL service).  When such a key is created, it should be
+given the server's secret key as the instantiation data (see the example
+below).
+
+        add_key("rxrpc_s", "52:2", secret_key, 8, keyring);
+
+A keyring is passed to the server socket by naming it in a sockopt.  The server
+socket then looks the server secret keys up in this keyring when secure
+incoming connections are made.  This can be seen in an example program that can
+be found at:
+
+        http://people.redhat.com/~dhowells/rxrpc/listen.c
+
+
+====================
+EXAMPLE CLIENT USAGE
+====================
+
+A client would issue an operation by:
+
+ (1) An RxRPC socket is set up by:
+
+        client = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);
+
+     Where the third parameter indicates the protocol family of the transport
+     socket used - usually IPv4 but it can also be IPv6 [TODO].
+
+ (2) A local address can optionally be bound:
+
+        struct sockaddr_rxrpc srx = {
+                .srx_family     = AF_RXRPC,
+                .srx_service    = 0,  /* we're a client */
+                .transport_type = SOCK_DGRAM,   /* type of transport socket */
+                .transport.sin_family   = AF_INET,
+                .transport.sin_port     = htons(7000), /* AFS callback */
+                .transport.sin_address  = 0,  /* all local interfaces */
+        };
+        bind(client, &srx, sizeof(srx));
+
+     This specifies the local UDP port to be used.  If not given, a random
+     non-privileged port will be used.  A UDP port may be shared between
+     several unrelated RxRPC sockets.  Security is handled on a basis of
+     per-RxRPC virtual connection.
+
+ (3) The security is set:
+
+        const char *key = "AFS:cambridge.redhat.com";
+        setsockopt(client, SOL_RXRPC, RXRPC_SECURITY_KEY, key, strlen(key));
+
+     This issues a request_key() to get the key representing the security
+     context.  The minimum security level can be set:
+
+        unsigned int sec = RXRPC_SECURITY_ENCRYPTED;
+        setsockopt(client, SOL_RXRPC, RXRPC_MIN_SECURITY_LEVEL,
+                   &sec, sizeof(sec));
+
+ (4) The server to be contacted can then be specified (alternatively this can
+     be done through sendmsg):
+
+        struct sockaddr_rxrpc srx = {
+                .srx_family     = AF_RXRPC,
+                .srx_service    = VL_SERVICE_ID,
+                .transport_type = SOCK_DGRAM,   /* type of transport socket */
+                .transport.sin_family   = AF_INET,
+                .transport.sin_port     = htons(7005), /* AFS volume manager */
+                .transport.sin_address  = ...,
+        };
+        connect(client, &srx, sizeof(srx));
+
+ (5) The request data should then be posted to the server socket using a series
+     of sendmsg() calls, each with the following control message attached:
+
+        RXRPC_USER_CALL_ID      - specifies the user ID for this call
+
+     MSG_MORE should be set in msghdr::msg_flags on all but the last part of
+     the request.  Multiple requests may be made simultaneously.
+
+     If a call is intended to go to a destination other then the default
+     specified through connect(), then msghdr::msg_name should be set on the
+     first request message of that call.
+
+ (6) The reply data will then be posted to the server socket for recvmsg() to
+     pick up.  MSG_MORE will be flagged by recvmsg() if there's more reply data
+     for a particular call to be read.  MSG_EOR will be set on the terminal
+     read for a call.
+
+     All data will be delivered with the following control message attached:
+
+        RXRPC_USER_CALL_ID      - specifies the user ID for this call
+
+     If an abort or error occurred, this will be returned in the control data
+     buffer instead, and MSG_EOR will be flagged to indicate the end of that
+     call.
+
+
+====================
+EXAMPLE SERVER USAGE
+====================
+
+A server would be set up to accept operations in the following manner:
+
+ (1) An RxRPC socket is created by:
+
+        server = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);
+
+     Where the third parameter indicates the address type of the transport
+     socket used - usually IPv4.
+
+ (2) Security is set up if desired by giving the socket a keyring with server
+     secret keys in it:
+
+        keyring = add_key("keyring", "AFSkeys", NULL, 0,
+                          KEY_SPEC_PROCESS_KEYRING);
+
+        const char secret_key[8] = {
+                0xa7, 0x83, 0x8a, 0xcb, 0xc7, 0x83, 0xec, 0x94 };
+        add_key("rxrpc_s", "52:2", secret_key, 8, keyring);
+
+        setsockopt(server, SOL_RXRPC, RXRPC_SECURITY_KEYRING, "AFSkeys", 7);
+
+     The keyring can be manipulated after it has been given to the socket. This
+     permits the server to add more keys, replace keys, etc. whilst it is live.
+
+ (2) A local address must then be bound:
+
+        struct sockaddr_rxrpc srx = {
+                .srx_family     = AF_RXRPC,
+                .srx_service    = VL_SERVICE_ID, /* RxRPC service ID */
+                .transport_type = SOCK_DGRAM,   /* type of transport socket */
+                .transport.sin_family   = AF_INET,
+                .transport.sin_port     = htons(7000), /* AFS callback */
+                .transport.sin_address  = 0,  /* all local interfaces */
+        };
+        bind(server, &srx, sizeof(srx));
+
+ (3) The server is then set to listen out for incoming calls:
+
+        listen(server, 100);
+
+ (4) The kernel notifies the server of pending incoming connections by sending
+     it a message for each.  This is received with recvmsg() on the server
+     socket.  It has no data, and has a single dataless control message
+     attached:
+
+        RXRPC_NEW_CALL
+
+     The address that can be passed back by recvmsg() at this point should be
+     ignored since the call for which the message was posted may have gone by
+     the time it is accepted - in which case the first call still on the queue
+     will be accepted.
+
+ (5) The server then accepts the new call by issuing a sendmsg() with two
+     pieces of control data and no actual data:
+
+        RXRPC_ACCEPT            - indicate connection acceptance
+        RXRPC_USER_CALL_ID      - specify user ID for this call
+
+ (6) The first request data packet will then be posted to the server socket for
+     recvmsg() to pick up.  At that point, the RxRPC address for the call can
+     be read from the address fields in the msghdr struct.
+
+     Subsequent request data will be posted to the server socket for recvmsg()
+     to collect as it arrives.  All but the last piece of the request data will
+     be delivered with MSG_MORE flagged.
+
+     All data will be delivered with the following control message attached:
+
+        RXRPC_USER_CALL_ID      - specifies the user ID for this call
+
+ (8) The reply data should then be posted to the server socket using a series
+     of sendmsg() calls, each with the following control messages attached:
+
+        RXRPC_USER_CALL_ID      - specifies the user ID for this call
+
+     MSG_MORE should be set in msghdr::msg_flags on all but the last message
+     for a particular call.
+
+ (9) The final ACK from the client will be posted for retrieval by recvmsg()
+     when it is received.  It will take the form of a dataless message with two
+     control messages attached:
+
+        RXRPC_USER_CALL_ID      - specifies the user ID for this call
+        RXRPC_ACK               - indicates final ACK (no data)
+
+     MSG_EOR will be flagged to indicate that this is the final message for
+     this call.
+
+(10) Up to the point the final packet of reply data is sent, the call can be
+     aborted by calling sendmsg() with a dataless message with the following
+     control messages attached:
+
+        RXRPC_USER_CALL_ID      - specifies the user ID for this call
+        RXRPC_ABORT             - indicates abort code (4 byte data)
+
+     Any packets waiting in the socket's receive queue will be discarded if
+     this is issued.
+
+Note that all the communications for a particular service take place through
+the one server socket, using control messages on sendmsg() and recvmsg() to
+determine the call affected.
+
+
+=========================
+AF_RXRPC KERNEL INTERFACE
+=========================
+
+The AF_RXRPC module also provides an interface for use by in-kernel utilities
+such as the AFS filesystem.  This permits such a utility to:
+
+ (1) Use different keys directly on individual client calls on one socket
+     rather than having to open a whole slew of sockets, one for each key it
+     might want to use.
+
+ (2) Avoid having RxRPC call request_key() at the point of issue of a call or
+     opening of a socket.  Instead the utility is responsible for requesting a
+     key at the appropriate point.  AFS, for instance, would do this during VFS
+     operations such as open() or unlink().  The key is then handed through
+     when the call is initiated.
+
+ (3) Request the use of something other than GFP_KERNEL to allocate memory.
+
+ (4) Avoid the overhead of using the recvmsg() call.  RxRPC messages can be
+     intercepted before they get put into the socket Rx queue and the socket
+     buffers manipulated directly.
+
+To use the RxRPC facility, a kernel utility must still open an AF_RXRPC socket,
+bind an addess as appropriate and listen if it's to be a server socket, but
+then it passes this to the kernel interface functions.
+
+The kernel interface functions are as follows:
+
+ (*) Begin a new client call.
+
+        struct rxrpc_call *
+        rxrpc_kernel_begin_call(struct socket *sock,
+                                struct sockaddr_rxrpc *srx,
+                                struct key *key,
+                                unsigned long user_call_ID,
+                                gfp_t gfp);
+
+     This allocates the infrastructure to make a new RxRPC call and assigns
+     call and connection numbers.  The call will be made on the UDP port that
+     the socket is bound to.  The call will go to the destination address of a
+     connected client socket unless an alternative is supplied (srx is
+     non-NULL).
+
+     If a key is supplied then this will be used to secure the call instead of
+     the key bound to the socket with the RXRPC_SECURITY_KEY sockopt.  Calls
+     secured in this way will still share connections if at all possible.
+
+     The user_call_ID is equivalent to that supplied to sendmsg() in the
+     control data buffer.  It is entirely feasible to use this to point to a
+     kernel data structure.
+
+     If this function is successful, an opaque reference to the RxRPC call is
+     returned.  The caller now holds a reference on this and it must be
+     properly ended.
+
+ (*) End a client call.
+
+        void rxrpc_kernel_end_call(struct rxrpc_call *call);
+
+     This is used to end a previously begun call.  The user_call_ID is expunged
+     from AF_RXRPC's knowledge and will not be seen again in association with
+     the specified call.
+
+ (*) Send data through a call.
+
+        int rxrpc_kernel_send_data(struct rxrpc_call *call, struct msghdr *msg,
+                                   size_t len);
+
+     This is used to supply either the request part of a client call or the
+     reply part of a server call.  msg.msg_iovlen and msg.msg_iov specify the
+     data buffers to be used.  msg_iov may not be NULL and must point
+     exclusively to in-kernel virtual addresses.  msg.msg_flags may be given
+     MSG_MORE if there will be subsequent data sends for this call.
+
+     The msg must not specify a destination address, control data or any flags
+     other than MSG_MORE.  len is the total amount of data to transmit.
+
+ (*) Abort a call.
+
+        void rxrpc_kernel_abort_call(struct rxrpc_call *call, u32 abort_code);
+
+     This is used to abort a call if it's still in an abortable state.  The
+     abort code specified will be placed in the ABORT message sent.
+
+ (*) Intercept received RxRPC messages.
+
+        typedef void (*rxrpc_interceptor_t)(struct sock *sk,
+                                            unsigned long user_call_ID,
+                                            struct sk_buff *skb);
+
+        void
+        rxrpc_kernel_intercept_rx_messages(struct socket *sock,
+                                           rxrpc_interceptor_t interceptor);
+
+     This installs an interceptor function on the specified AF_RXRPC socket.
+     All messages that would otherwise wind up in the socket's Rx queue are
+     then diverted to this function.  Note that care must be taken to process
+     the messages in the right order to maintain DATA message sequentiality.
+
+     The interceptor function itself is provided with the address of the socket
+     and handling the incoming message, the ID assigned by the kernel utility
+     to the call and the socket buffer containing the message.
+
+     The skb->mark field indicates the type of message:
+
+        MARK                            MEANING
+        =============================== =======================================
+        RXRPC_SKB_MARK_DATA             Data message
+        RXRPC_SKB_MARK_FINAL_ACK        Final ACK received for an incoming call
+        RXRPC_SKB_MARK_BUSY             Client call rejected as server busy
+        RXRPC_SKB_MARK_REMOTE_ABORT     Call aborted by peer
+        RXRPC_SKB_MARK_NET_ERROR        Network error detected
+        RXRPC_SKB_MARK_LOCAL_ERROR      Local error encountered
+        RXRPC_SKB_MARK_NEW_CALL         New incoming call awaiting acceptance
+
+     The remote abort message can be probed with rxrpc_kernel_get_abort_code().
+     The two error messages can be probed with rxrpc_kernel_get_error_number().
+     A new call can be accepted with rxrpc_kernel_accept_call().
+
+     Data messages can have their contents extracted with the usual bunch of
+     socket buffer manipulation functions.  A data message can be determined to
+     be the last one in a sequence with rxrpc_kernel_is_data_last().  When a
+     data message has been used up, rxrpc_kernel_data_delivered() should be
+     called on it..
+
+     Non-data messages should be handled to rxrpc_kernel_free_skb() to dispose
+     of.  It is possible to get extra refs on all types of message for later
+     freeing, but this may pin the state of a call until the message is finally
+     freed.
+
+ (*) Accept an incoming call.
+
+        struct rxrpc_call *
+        rxrpc_kernel_accept_call(struct socket *sock,
+                                 unsigned long user_call_ID);
+
+     This is used to accept an incoming call and to assign it a call ID.  This
+     function is similar to rxrpc_kernel_begin_call() and calls accepted must
+     be ended in the same way.
+
+     If this function is successful, an opaque reference to the RxRPC call is
+     returned.  The caller now holds a reference on this and it must be
+     properly ended.
+
+ (*) Reject an incoming call.
+
+        int rxrpc_kernel_reject_call(struct socket *sock);
+
+     This is used to reject the first incoming call on the socket's queue with
+     a BUSY message.  -ENODATA is returned if there were no incoming calls.
+     Other errors may be returned if the call had been aborted (-ECONNABORTED)
+     or had timed out (-ETIME).
+
+ (*) Record the delivery of a data message and free it.
+
+        void rxrpc_kernel_data_delivered(struct sk_buff *skb);
+
+     This is used to record a data message as having been delivered and to
+     update the ACK state for the call.  The socket buffer will be freed.
+
+ (*) Free a message.
+
+        void rxrpc_kernel_free_skb(struct sk_buff *skb);
+
+     This is used to free a non-DATA socket buffer intercepted from an AF_RXRPC
+     socket.
+
+ (*) Determine if a data message is the last one on a call.
+
+        bool rxrpc_kernel_is_data_last(struct sk_buff *skb);
+
+     This is used to determine if a socket buffer holds the last data message
+     to be received for a call (true will be returned if it does, false
+     if not).
+
+     The data message will be part of the reply on a client call and the
+     request on an incoming call.  In the latter case there will be more
+     messages, but in the former case there will not.
+
+ (*) Get the abort code from an abort message.
+
+        u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb);
+
+     This is used to extract the abort code from a remote abort message.
+
+ (*) Get the error number from a local or network error message.
+
+        int rxrpc_kernel_get_error_number(struct sk_buff *skb);
+
+     This is used to extract the error number from a message indicating either
+     a local error occurred or a network error occurred.
diff --git a/Documentation/networking/wan-router.txt b/Documentation/networking/wan-router.txt
index 653978dcea7f..07dd6d9930a1 100644
--- a/Documentation/networking/wan-router.txt
+++ b/Documentation/networking/wan-router.txt
@@ -250,7 +250,6 @@ PRODUCT COMPONENTS AND RELATED FILES
         sdladrv.h       SDLA support module API definitions
         sdlasfm.h       SDLA firmware module definitions
         if_wanpipe.h    WANPIPE Socket definitions
-        if_wanpipe_common.h     WANPIPE Socket/Driver common definitions.
         sdlapci.h       WANPIPE PCI definitions