diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 40 | ||||
| -rw-r--r-- | Documentation/filesystems/afs.txt | 214 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.txt | 9 | ||||
| -rw-r--r-- | Documentation/keys.txt | 12 | ||||
| -rw-r--r-- | Documentation/networking/bonding.txt | 35 | ||||
| -rw-r--r-- | Documentation/networking/dccp.txt | 10 | ||||
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 31 | ||||
| -rw-r--r-- | Documentation/networking/rxrpc.txt | 859 | ||||
| -rw-r--r-- | Documentation/networking/wan-router.txt | 1 |
9 files changed, 1093 insertions, 118 deletions
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 19b4c96b2a4..6da663607f7 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 - ---------------------------- - What: i8xx_tco watchdog driver When: in 2.6.22 Why: the i8xx_tco watchdog driver has been replaced by the iTCO_wdt @@ -313,3 +292,22 @@ Why: the i8xx_tco watchdog driver has been replaced by the iTCO_wdt Who: Wim Van Sebroeck 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 2f4237dfb8c..12ad6c7f4e5 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 5484ab5efd4..7aaf09b86a5 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 60c665d9cfa..81d9aa09729 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 de809e58092..1da56663083 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 387482e46c4..4504cc59e40 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 702d1d8dd04..af6a63ab902 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 00000000000..cae231b1c13 --- /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 653978dcea7..07dd6d9930a 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 |