diff options
Diffstat (limited to 'Documentation/networking')
| -rw-r--r-- | Documentation/networking/00-INDEX | 3 | ||||
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 3 | ||||
| -rw-r--r-- | Documentation/networking/l2tp.txt | 169 | ||||
| -rw-r--r-- | Documentation/networking/multiqueue.txt | 111 | ||||
| -rw-r--r-- | Documentation/networking/netdevices.txt | 38 | ||||
| -rw-r--r-- | Documentation/networking/sk98lin.txt | 568 | ||||
| -rw-r--r-- | Documentation/networking/spider_net.txt | 204 |
7 files changed, 517 insertions, 579 deletions
diff --git a/Documentation/networking/00-INDEX b/Documentation/networking/00-INDEX index 153d84d281e6..d63f480afb74 100644 --- a/Documentation/networking/00-INDEX +++ b/Documentation/networking/00-INDEX @@ -96,9 +96,6 @@ routing.txt - the new routing mechanism shaper.txt - info on the module that can shape/limit transmitted traffic. -sk98lin.txt - - Marvell Yukon Chipset / SysKonnect SK-98xx compliant Gigabit - Ethernet Adapter family driver info skfp.txt - SysKonnect FDDI (SK-5xxx, Compaq Netelligent) driver info. smc9.txt diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 8f6067ea5e3e..32c2e9da5f3a 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -880,8 +880,7 @@ accept_redirects - BOOLEAN accept_source_route - INTEGER Accept source routing (routing extension header). - > 0: Accept routing header. - = 0: Accept only routing header type 2. + >= 0: Accept only routing header type 2. < 0: Do not accept routing header. Default: 0 diff --git a/Documentation/networking/l2tp.txt b/Documentation/networking/l2tp.txt new file mode 100644 index 000000000000..2451f551c505 --- /dev/null +++ b/Documentation/networking/l2tp.txt @@ -0,0 +1,169 @@ +This brief document describes how to use the kernel's PPPoL2TP driver +to provide L2TP functionality. L2TP is a protocol that tunnels one or +more PPP sessions over a UDP tunnel. It is commonly used for VPNs +(L2TP/IPSec) and by ISPs to tunnel subscriber PPP sessions over an IP +network infrastructure. + +Design +====== + +The PPPoL2TP driver, drivers/net/pppol2tp.c, provides a mechanism by +which PPP frames carried through an L2TP session are passed through +the kernel's PPP subsystem. The standard PPP daemon, pppd, handles all +PPP interaction with the peer. PPP network interfaces are created for +each local PPP endpoint. + +The L2TP protocol http://www.faqs.org/rfcs/rfc2661.html defines L2TP +control and data frames. L2TP control frames carry messages between +L2TP clients/servers and are used to setup / teardown tunnels and +sessions. An L2TP client or server is implemented in userspace and +will use a regular UDP socket per tunnel. L2TP data frames carry PPP +frames, which may be PPP control or PPP data. The kernel's PPP +subsystem arranges for PPP control frames to be delivered to pppd, +while data frames are forwarded as usual. + +Each tunnel and session within a tunnel is assigned a unique tunnel_id +and session_id. These ids are carried in the L2TP header of every +control and data packet. The pppol2tp driver uses them to lookup +internal tunnel and/or session contexts. Zero tunnel / session ids are +treated specially - zero ids are never assigned to tunnels or sessions +in the network. In the driver, the tunnel context keeps a pointer to +the tunnel UDP socket. The session context keeps a pointer to the +PPPoL2TP socket, as well as other data that lets the driver interface +to the kernel PPP subsystem. + +Note that the pppol2tp kernel driver handles only L2TP data frames; +L2TP control frames are simply passed up to userspace in the UDP +tunnel socket. The kernel handles all datapath aspects of the +protocol, including data packet resequencing (if enabled). + +There are a number of requirements on the userspace L2TP daemon in +order to use the pppol2tp driver. + +1. Use a UDP socket per tunnel. + +2. Create a single PPPoL2TP socket per tunnel bound to a special null + session id. This is used only for communicating with the driver but + must remain open while the tunnel is active. Opening this tunnel + management socket causes the driver to mark the tunnel socket as an + L2TP UDP encapsulation socket and flags it for use by the + referenced tunnel id. This hooks up the UDP receive path via + udp_encap_rcv() in net/ipv4/udp.c. PPP data frames are never passed + in this special PPPoX socket. + +3. Create a PPPoL2TP socket per L2TP session. This is typically done + by starting pppd with the pppol2tp plugin and appropriate + arguments. A PPPoL2TP tunnel management socket (Step 2) must be + created before the first PPPoL2TP session socket is created. + +When creating PPPoL2TP sockets, the application provides information +to the driver about the socket in a socket connect() call. Source and +destination tunnel and session ids are provided, as well as the file +descriptor of a UDP socket. See struct pppol2tp_addr in +include/linux/if_ppp.h. Note that zero tunnel / session ids are +treated specially. When creating the per-tunnel PPPoL2TP management +socket in Step 2 above, zero source and destination session ids are +specified, which tells the driver to prepare the supplied UDP file +descriptor for use as an L2TP tunnel socket. + +Userspace may control behavior of the tunnel or session using +setsockopt and ioctl on the PPPoX socket. The following socket +options are supported:- + +DEBUG - bitmask of debug message categories. See below. +SENDSEQ - 0 => don't send packets with sequence numbers + 1 => send packets with sequence numbers +RECVSEQ - 0 => receive packet sequence numbers are optional + 1 => drop receive packets without sequence numbers +LNSMODE - 0 => act as LAC. + 1 => act as LNS. +REORDERTO - reorder timeout (in millisecs). If 0, don't try to reorder. + +Only the DEBUG option is supported by the special tunnel management +PPPoX socket. + +In addition to the standard PPP ioctls, a PPPIOCGL2TPSTATS is provided +to retrieve tunnel and session statistics from the kernel using the +PPPoX socket of the appropriate tunnel or session. + +Debugging +========= + +The driver supports a flexible debug scheme where kernel trace +messages may be optionally enabled per tunnel and per session. Care is +needed when debugging a live system since the messages are not +rate-limited and a busy system could be swamped. Userspace uses +setsockopt on the PPPoX socket to set a debug mask. + +The following debug mask bits are available: + +PPPOL2TP_MSG_DEBUG verbose debug (if compiled in) +PPPOL2TP_MSG_CONTROL userspace - kernel interface +PPPOL2TP_MSG_SEQ sequence numbers handling +PPPOL2TP_MSG_DATA data packets + +Sample Userspace Code +===================== + +1. Create tunnel management PPPoX socket + + kernel_fd = socket(AF_PPPOX, SOCK_DGRAM, PX_PROTO_OL2TP); + if (kernel_fd >= 0) { + struct sockaddr_pppol2tp sax; + struct sockaddr_in const *peer_addr; + + peer_addr = l2tp_tunnel_get_peer_addr(tunnel); + memset(&sax, 0, sizeof(sax)); + sax.sa_family = AF_PPPOX; + sax.sa_protocol = PX_PROTO_OL2TP; + sax.pppol2tp.fd = udp_fd; /* fd of tunnel UDP socket */ + sax.pppol2tp.addr.sin_addr.s_addr = peer_addr->sin_addr.s_addr; + sax.pppol2tp.addr.sin_port = peer_addr->sin_port; + sax.pppol2tp.addr.sin_family = AF_INET; + sax.pppol2tp.s_tunnel = tunnel_id; + sax.pppol2tp.s_session = 0; /* special case: mgmt socket */ + sax.pppol2tp.d_tunnel = 0; + sax.pppol2tp.d_session = 0; /* special case: mgmt socket */ + + if(connect(kernel_fd, (struct sockaddr *)&sax, sizeof(sax) ) < 0 ) { + perror("connect failed"); + result = -errno; + goto err; + } + } + +2. Create session PPPoX data socket + + struct sockaddr_pppol2tp sax; + int fd; + + /* Note, the target socket must be bound already, else it will not be ready */ + sax.sa_family = AF_PPPOX; + sax.sa_protocol = PX_PROTO_OL2TP; + sax.pppol2tp.fd = tunnel_fd; + sax.pppol2tp.addr.sin_addr.s_addr = addr->sin_addr.s_addr; + sax.pppol2tp.addr.sin_port = addr->sin_port; + sax.pppol2tp.addr.sin_family = AF_INET; + sax.pppol2tp.s_tunnel = tunnel_id; + sax.pppol2tp.s_session = session_id; + sax.pppol2tp.d_tunnel = peer_tunnel_id; + sax.pppol2tp.d_session = peer_session_id; + + /* session_fd is the fd of the session's PPPoL2TP socket. + * tunnel_fd is the fd of the tunnel UDP socket. + */ + fd = connect(session_fd, (struct sockaddr *)&sax, sizeof(sax)); + if (fd < 0 ) { + return -errno; + } + return 0; + +Miscellanous +============ + +The PPPoL2TP driver was developed as part of the OpenL2TP project by +Katalix Systems Ltd. OpenL2TP is a full-featured L2TP client / server, +designed from the ground up to have the L2TP datapath in the +kernel. The project also implemented the pppol2tp plugin for pppd +which allows pppd to use the kernel driver. Details can be found at +http://openl2tp.sourceforge.net. diff --git a/Documentation/networking/multiqueue.txt b/Documentation/networking/multiqueue.txt new file mode 100644 index 000000000000..00b60cce2224 --- /dev/null +++ b/Documentation/networking/multiqueue.txt @@ -0,0 +1,111 @@ + + HOWTO for multiqueue network device support + =========================================== + +Section 1: Base driver requirements for implementing multiqueue support +Section 2: Qdisc support for multiqueue devices +Section 3: Brief howto using PRIO or RR for multiqueue devices + + +Intro: Kernel support for multiqueue devices +--------------------------------------------------------- + +Kernel support for multiqueue devices is only an API that is presented to the +netdevice layer for base drivers to implement. This feature is part of the +core networking stack, and all network devices will be running on the +multiqueue-aware stack. If a base driver only has one queue, then these +changes are transparent to that driver. + + +Section 1: Base driver requirements for implementing multiqueue support +----------------------------------------------------------------------- + +Base drivers are required to use the new alloc_etherdev_mq() or +alloc_netdev_mq() functions to allocate the subqueues for the device. The +underlying kernel API will take care of the allocation and deallocation of +the subqueue memory, as well as netdev configuration of where the queues +exist in memory. + +The base driver will also need to manage the queues as it does the global +netdev->queue_lock today. Therefore base drivers should use the +netif_{start|stop|wake}_subqueue() functions to manage each queue while the +device is still operational. netdev->queue_lock is still used when the device +comes online or when it's completely shut down (unregister_netdev(), etc.). + +Finally, the base driver should indicate that it is a multiqueue device. The +feature flag NETIF_F_MULTI_QUEUE should be added to the netdev->features +bitmap on device initialization. Below is an example from e1000: + +#ifdef CONFIG_E1000_MQ + if ( (adapter->hw.mac.type == e1000_82571) || + (adapter->hw.mac.type == e1000_82572) || + (adapter->hw.mac.type == e1000_80003es2lan)) + netdev->features |= NETIF_F_MULTI_QUEUE; +#endif + + +Section 2: Qdisc support for multiqueue devices +----------------------------------------------- + +Currently two qdiscs support multiqueue devices. A new round-robin qdisc, +sch_rr, and sch_prio. The qdisc is responsible for classifying the skb's to +bands and queues, and will store the queue mapping into skb->queue_mapping. +Use this field in the base driver to determine which queue to send the skb +to. + +sch_rr has been added for hardware that doesn't want scheduling policies from +software, so it's a straight round-robin qdisc. It uses the same syntax and +classification priomap that sch_prio uses, so it should be intuitive to +configure for people who've used sch_prio. + +The PRIO qdisc naturally plugs into a multiqueue device. If PRIO has been +built with NET_SCH_PRIO_MQ, then upon load, it will make sure the number of +bands requested is equal to the number of queues on the hardware. If they +are equal, it sets a one-to-one mapping up between the queues and bands. If +they're not equal, it will not load the qdisc. This is the same behavior +for RR. Once the association is made, any skb that is classified will have +skb->queue_mapping set, which will allow the driver to properly queue skb's +to multiple queues. + + +Section 3: Brief howto using PRIO and RR for multiqueue devices +--------------------------------------------------------------- + +The userspace command 'tc,' part of the iproute2 package, is used to configure +qdiscs. To add the PRIO qdisc to your network device, assuming the device is +called eth0, run the following command: + +# tc qdisc add dev eth0 root handle 1: prio bands 4 multiqueue + +This will create 4 bands, 0 being highest priority, and associate those bands +to the queues on your NIC. Assuming eth0 has 4 Tx queues, the band mapping +would look like: + +band 0 => queue 0 +band 1 => queue 1 +band 2 => queue 2 +band 3 => queue 3 + +Traffic will begin flowing through each queue if your TOS values are assigning +traffic across the various bands. For example, ssh traffic will always try to +go out band 0 based on TOS -> Linux priority conversion (realtime traffic), +so it will be sent out queue 0. ICMP traffic (pings) fall into the "normal" +traffic classification, which is band 1. Therefore pings will be send out +queue 1 on the NIC. + +Note the use of the multiqueue keyword. This is only in versions of iproute2 +that support multiqueue networking devices; if this is omitted when loading +a qdisc onto a multiqueue device, the qdisc will load and operate the same +if it were loaded onto a single-queue device (i.e. - sends all traffic to +queue 0). + +Another alternative to multiqueue band allocation can be done by using the +multiqueue option and specify 0 bands. If this is the case, the qdisc will +allocate the number of bands to equal the number of queues that the device +reports, and bring the qdisc online. + +The behavior of tc filters remains the same, where it will override TOS priority +classification. + + +Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com> diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt index ce1361f95243..37869295fc70 100644 --- a/Documentation/networking/netdevices.txt +++ b/Documentation/networking/netdevices.txt @@ -20,6 +20,30 @@ private data which gets freed when the network device is freed. If separately allocated data is attached to the network device (dev->priv) then it is up to the module exit handler to free that. +MTU +=== +Each network device has a Maximum Transfer Unit. The MTU does not +include any link layer protocol overhead. Upper layer protocols must +not pass a socket buffer (skb) to a device to transmit with more data +than the mtu. The MTU does not include link layer header overhead, so +for example on Ethernet if the standard MTU is 1500 bytes used, the +actual skb will contain up to 1514 bytes because of the Ethernet +header. Devices should allow for the 4 byte VLAN header as well. + +Segmentation Offload (GSO, TSO) is an exception to this rule. The +upper layer protocol may pass a large socket buffer to the device +transmit routine, and the device will break that up into separate +packets based on the current MTU. + +MTU is symmetrical and applies both to receive and transmit. A device +must be able to receive at least the maximum size packet allowed by +the MTU. A network device may use the MTU as mechanism to size receive +buffers, but the device should allow packets with VLAN header. With +standard Ethernet mtu of 1500 bytes, the device should allow up to +1518 byte packets (1500 + 14 header + 4 tag). The device may either: +drop, truncate, or pass up oversize packets, but dropping oversize +packets is preferred. + struct net_device synchronization rules ======================================= @@ -43,16 +67,17 @@ dev->get_stats: dev->hard_start_xmit: Synchronization: netif_tx_lock spinlock. + When the driver sets NETIF_F_LLTX in dev->features this will be called without holding netif_tx_lock. In this case the driver has to lock by itself when needed. It is recommended to use a try lock - for this and return -1 when the spin lock fails. + for this and return NETDEV_TX_LOCKED when the spin lock fails. The locking there should also properly protect against - set_multicast_list - Context: Process with BHs disabled or BH (timer). - Notes: netif_queue_stopped() is guaranteed false - Interrupts must be enabled when calling hard_start_xmit. - (Interrupts must also be enabled when enabling the BH handler.) + set_multicast_list. + + Context: Process with BHs disabled or BH (timer), + will be called with interrupts disabled by netconsole. + Return codes: o NETDEV_TX_OK everything ok. o NETDEV_TX_BUSY Cannot transmit packet, try later @@ -74,4 +99,5 @@ dev->poll: Synchronization: __LINK_STATE_RX_SCHED bit in dev->state. See dev_close code and comments in net/core/dev.c for more info. Context: softirq + will be called with interrupts disabled by netconsole. diff --git a/Documentation/networking/sk98lin.txt b/Documentation/networking/sk98lin.txt deleted file mode 100644 index 8590a954df1d..000000000000 --- a/Documentation/networking/sk98lin.txt +++ /dev/null @@ -1,568 +0,0 @@ -(C)Copyright 1999-2004 Marvell(R). -All rights reserved -=========================================================================== - -sk98lin.txt created 13-Feb-2004 - -Readme File for sk98lin v6.23 -Marvell Yukon/SysKonnect SK-98xx Gigabit Ethernet Adapter family driver for LINUX - -This file contains - 1 Overview - 2 Required Files - 3 Installation - 3.1 Driver Installation - 3.2 Inclusion of adapter at system start - 4 Driver Parameters - 4.1 Per-Port Parameters - 4.2 Adapter Parameters - 5 Large Frame Support - 6 VLAN and Link Aggregation Support (IEEE 802.1, 802.1q, 802.3ad) - 7 Troubleshooting - -=========================================================================== - - -1 Overview -=========== - -The sk98lin driver supports the Marvell Yukon and SysKonnect -SK-98xx/SK-95xx compliant Gigabit Ethernet Adapter on Linux. It has -been tested with Linux on Intel/x86 machines. -*** - - -2 Required Files -================= - -The linux kernel source. -No additional files required. -*** - - -3 Installation -=============== - -It is recommended to download the latest version of the driver from the -SysKonnect web site www.syskonnect.com. If you have downloaded the latest -driver, the Linux kernel has to be patched before the driver can be -installed. For details on how to patch a Linux kernel, refer to the -patch.txt file. - -3.1 Driver Installation ------------------------- - -The following steps describe the actions that are required to install -the driver and to start it manually. These steps should be carried -out for the initial driver setup. Once confirmed to be ok, they can -be included in the system start. - -NOTE 1: To perform the following tasks you need 'root' access. - -NOTE 2: In case of problems, please read the section "Troubleshooting" - below. - -The driver can either be integrated into the kernel or it can be compiled -as a module. Select the appropriate option during the kernel -configuration. - -Compile/use the driver as a module ----------------------------------- -To compile the driver, go to the directory /usr/src/linux and -execute the command "make menuconfig" or "make xconfig" and proceed as -follows: - -To integrate the driver permanently into the kernel, proceed as follows: - -1. Select the menu "Network device support" and then "Ethernet(1000Mbit)" -2. Mark "Marvell Yukon Chipset / SysKonnect SK-98xx family support" - with (*) -3. Build a new kernel when the configuration of the above options is - finished. -4. Install the new kernel. -5. Reboot your system. - -To use the driver as a module, proceed as follows: - -1. Enable 'loadable module support' in the kernel. -2. For automatic driver start, enable the 'Kernel module loader'. -3. Select the menu "Network device support" and then "Ethernet(1000Mbit)" -4. Mark "Marvell Yukon Chipset / SysKonnect SK-98xx family support" - with (M) -5. Execute the command "make modules". -6. Execute the command "make modules_install". - The appropriate modules will be installed. -7. Reboot your system. - - -Load the module manually ------------------------- -To load the module manually, proceed as follows: - -1. Enter "modprobe sk98lin". -2. If a Marvell Yukon or SysKonnect SK-98xx adapter is installed in - your computer and you have a /proc file system, execute the command: - "ls /proc/net/sk98lin/" - This should produce an output containing a line with the following - format: - eth0 eth1 ... - which indicates that your adapter has been found and initialized. - - NOTE 1: If you have more than one Marvell Yukon or SysKonnect SK-98xx - adapter installed, the adapters will be listed as 'eth0', - 'eth1', 'eth2', etc. - For each adapter, repeat steps 3 and 4 below. - - NOTE 2: If you have other Ethernet adapters installed, your Marvell - Yukon or SysKonnect SK-98xx adapter will be mapped to the - next available number, e.g. 'eth1'. The mapping is executed - automatically. - The module installation message (displayed either in a system - log file or on the console) prints a line for each adapter - found containing the corresponding 'ethX'. - -3. Select an IP address and assign it to the respective adapter by - entering: - ifconfig eth0 <ip-address> - With this command, the adapter is connected to the Ethernet. - - SK-98xx Gigabit Ethernet Server Adapters: The yellow LED on the adapter - is now active, the link status LED of the primary port is active and - the link status LED of the secondary port (on dual port adapters) is - blinking (if the ports are connected to a switch or hub). - SK-98xx V2.0 Gigabit Ethernet Adapters: The link status LED is active. - In addition, you will receive a status message on the console stating - "ethX: network connection up using port Y" and showing the selected - connection parameters (x stands for the ethernet device number - (0,1,2, etc), y stands for the port name (A or B)). - - NOTE: If you are in doubt about IP addresses, ask your network - administrator for assistance. - -4. Your adapter should now be fully operational. - Use 'ping <otherstation>' to verify the connection to other computers - on your network. -5. To check the adapter configuration view /proc/net/sk98lin/[devicename]. - For example by executing: - "cat /proc/net/sk98lin/eth0" - -Unload the module ------------------ -To stop and unload the driver modules, proceed as follows: - -1. Execute the command "ifconfig eth0 down". -2. Execute the command "rmmod sk98lin". - -3.2 Inclusion of adapter at system start ------------------------------------------ - -Since a large number of different Linux distributions are -available, we are unable to describe a general installation procedure -for the driver module. -Because the driver is now integrated in the kernel, installation should -be easy, using the standard mechanism of your distribution. -Refer to the distribution's manual for installation of ethernet adapters. - -*** - -4 Driver Parameters -==================== - -Parameters can be set at the command line after the module has been -loaded with the command 'modprobe'. -In some distributions, the configuration tools are able to pass parameters -to the driver module. - -If you use the kernel module loader, you can set driver parameters -in the file /etc/modprobe.conf (or /etc/modules.conf in 2.4 or earlier). -To set the driver parameters in this file, proceed as follows: - -1. Insert a line of the form : - options sk98lin ... - For "...", the same syntax is required as described for the command - line parameters of modprobe below. -2. To activate the new parameters, either reboot your computer - or - unload and reload the driver. - The syntax of the driver parameters is: - - modprobe sk98lin parameter=value1[,value2[,value3...]] - - where value1 refers to the first adapter, value2 to the second etc. - -NOTE: All parameters are case sensitive. Write them exactly as shown - below. - -Example: -Suppose you have two adapters. You want to set auto-negotiation -on the first adapter to ON and on the second adapter to OFF. -You also want to set DuplexCapabilities on the first adapter -to FULL, and on the second adapter to HALF. -Then, you must enter: - - modprobe sk98lin AutoNeg_A=On,Off DupCap_A=Full,Half - -NOTE: The number of adapters that can be configured this way is - limited in the driver (file skge.c, constant SK_MAX_CARD_PARAM). - The current limit is 16. If you happen to install - more adapters, adjust this and recompile. - - -4.1 Per-Port Parameters ------------------------- - -These settings are available for each port on the adapter. -In the following description, '?' stands for the port for -which you set the parameter (A or B). - -Speed ------ -Parameter: Speed_? -Values: 10, 100, 1000, Auto -Default: Auto - -This parameter is used to set the speed capabilities. It is only valid -for the SK-98xx V2.0 copper adapters. -Usually, the speed is negotiated between the two ports during link -establishment. If this fails, a port can be forced to a specific setting -with this parameter. - -Auto-Negotiation ----------------- -Parameter: AutoNeg_? -Values: On, Off, Sense -Default: On - -The "Sense"-mode automatically detects whether the link partner supports -auto-negotiation or not. - -Duplex Capabilities -------------------- -Parameter: DupCap_? -Values: Half, Full, Both -Default: Both - -This parameters is only relevant if auto-negotiation for this port is -not set to "Sense". If auto-negotiation is set to "On", all three values -are possible. If it is set to "Off", only "Full" and "Half" are allowed. -This parameter is useful if your link partner does not support all -possible combinations. - -Flow Control ------------- -Parameter: FlowCtrl_? -Values: Sym, SymOrRem, LocSend, None -Default: SymOrRem - -This parameter can be used to set the flow control capabilities the -port reports during auto-negotiation. It can be set for each port -individually. -Possible modes: - -- Sym = Symmetric: both link partners are allowed to send - PAUSE frames - -- SymOrRem = SymmetricOrRemote: both or only remote partner - are allowed to send PAUSE frames - -- LocSend = LocalSend: only local link partner is allowed - to send PAUSE frames - -- None = no link partner is allowed to send PAUSE frames - -NOTE: This parameter is ignored if auto-negotiation is set to "Off". - -Role in Master-Slave-Negotiation (1000Base-T only) --------------------------------------------------- -Parameter: Role_? -Values: Auto, Master, Slave -Default: Auto - -This parameter is only valid for the SK-9821 and SK-9822 adapters. -For two 1000Base-T ports to communicate, one must take the role of the -master (providing timing information), while the other must be the -slave. Usually, this is negotiated between the two ports during link -establishment. If this fails, a port can be forced to a specific setting -with this parameter. - - -4.2 Adapter Parameters ------------------------ - -Connection Type (SK-98xx V2.0 copper adapters only) ---------------- -Parameter: ConType -Values: Auto, 100FD, 100HD, 10FD, 10HD -Default: Auto - -The parameter 'ConType' is a combination of all five per-port parameters -within one single parameter. This simplifies the configuration of both ports -of an adapter card! The different values of this variable reflect the most -meaningful combinations of port parameters. - -The following table shows the values of 'ConType' and the corresponding -combinations of the per-port parameters: - - ConType | DupCap AutoNeg FlowCtrl Role Speed - ----------+------------------------------------------------------ - Auto | Both On SymOrRem Auto Auto - 100FD | Full Off None Auto (ignored) 100 - 100HD | Half Off None Auto (ignored) 100 - 10FD | Full Off None Auto (ignored) 10 - 10HD | Half Off None Auto (ignored) 10 - -Stating any other port parameter together with this 'ConType' variable -will result in a merged configuration of those settings. This due to -the fact, that the per-port parameters (e.g. Speed_? ) have a higher -priority than the combined variable 'ConType'. - -NOTE: This parameter is always used on both ports of the adapter card. - -Interrupt Moderation --------------------- -Parameter: Moderation -Values: None, Static, Dynamic -Default: None - -Interrupt moderation is employed to limit the maximum number of interrupts -the driver has to serve. That is, one or more interrupts (which indicate any -transmit or receive packet to be processed) are queued until the driver -processes them. When queued interrupts are to be served, is determined by the -'IntsPerSec' parameter, which is explained later below. - -Possible modes: - - -- None - No interrupt moderation is applied on the adapter card. - Therefore, each transmit or receive interrupt is served immediately - as soon as it appears on the interrupt line of the adapter card. - - -- Static - Interrupt moderation is applied on the adapter card. - All transmit and receive interrupts are queued until a complete - moderation interval ends. If such a moderation interval ends, all - queued interrupts are processed in one big bunch without any delay. - The term 'static' reflects the fact, that interrupt moderation is - always enabled, regardless how much network load is currently - passing via a particular interface. In addition, the duration of - the moderation interval has a fixed length that never changes while - the driver is operational. - - -- Dynamic - Interrupt moderation might be applied on the adapter card, - depending on the load of the system. If the driver detects that the - system load is too high, the driver tries to shield the system against - too much network load by enabling interrupt moderation. If - at a later - time - the CPU utilization decreases again (or if the network load is - negligible) the interrupt moderation will automatically be disabled. - -Interrupt moderation should be used when the driver has to handle one or more -interfaces with a high network load, which - as a consequence - leads also to a -high CPU utilization. When moderation is applied in such high network load -situations, CPU load might be reduced by 20-30%. - -NOTE: The drawback of using interrupt moderation is an increase of the round- -trip-time (RTT), due to the queueing and serving of interrupts at dedicated -moderation times. - -Interrupts per second ---------------------- -Parameter: IntsPerSec -Values: 30...40000 (interrupts per second) -Default: 2000 - -This parameter is only used if either static or dynamic interrupt moderation -is used on a network adapter card. Using this parameter if no moderation is -applied will lead to no action performed. - -This parameter determines the length of any interrupt moderation interval. -Assuming that static interrupt moderation is to be used, an 'IntsPerSec' -parameter value of 2000 will lead to an interrupt moderation interval of -500 microseconds. - -NOTE: The duration of the moderation interval is to be chosen with care. -At first glance, selecting a very long duration (e.g. only 100 interrupts per -second) seems to be meaningful, but the increase of packet-processing delay -is tremendous. On the other hand, selecting a very short moderation time might -compensate the use of any moderation being applied. - - -Preferred Port --------------- -Parameter: PrefPort -Values: A, B -Default: A - -This is used to force the preferred port to A or B (on dual-port network -adapters). The preferred port is the one that is used if both are detected -as fully functional. - -RLMT Mode (Redundant Link Management Technology) ------------------------------------------------- -Parameter: RlmtMode -Values: CheckLinkState,CheckLocalPort, CheckSeg, DualNet -Default: CheckLinkState - -RLMT monitors the status of the port. If the link of the active port -fails, RLMT switches immediately to the standby link. The virtual link is -maintained as long as at least one 'physical' link is up. - -Possible modes: - - -- CheckLinkState - Check link state only: RLMT uses the link state - reported by the adapter hardware for each individual port to - determine whether a port can be used for all network traffic or - not. - - -- CheckLocalPort - In this mode, RLMT monitors the network path - between the two ports of an adapter by regularly exchanging packets - between them. This mode requires a network configuration in which - the two ports are able to "see" each other (i.e. there must not be - any router between the ports). - - -- CheckSeg - Check local port and segmentation: This mode supports the - same functions as the CheckLocalPort mode and additionally checks - network segmentation between the ports. Therefore, this mode is only - to be used if Gigabit Ethernet switches are installed on the network - that have been configured to use the Spanning Tree protocol. - - -- DualNet - In this mode, ports A and B are used as separate devices. - If you have a dual port adapter, port A will be configured as eth0 - and port B as eth1. Both ports can be used independently with - distinct IP addresses. The preferred port setting is not used. - RLMT is turned off. - -NOTE: RLMT modes CLP and CLPSS are designed to operate in configurations - where a network path between the ports on one adapter exists. - Moreover, they are not designed to work where adapters are connected - back-to-back. -*** - - -5 Large Frame Support -====================== - -The driver supports large frames (also called jumbo frames). Using large -frames can result in an improved throughput if transferring large amounts -of data. -To enable large frames, set the MTU (maximum transfer unit) of the -interface to the desired value (up to 9000), execute the following -command: - ifconfig eth0 mtu 9000 -This will only work if you have two adapters connected back-to-back -or if you use a switch that supports large frames. When using a switch, -it should be configured to allow large frames and auto-negotiation should -be set to OFF. The setting must be configured on all adapters that can be -reached by the large frames. If one adapter is not set to receive large -frames, it will simply drop them. - -You can switch back to the standard ethernet frame size by executing the -following command: - ifconfig eth0 mtu 1500 - -To permanently configure this setting, add a script with the 'ifconfig' -line to the system startup sequence (named something like "S99sk98lin" -in /etc/rc.d/rc2.d). -*** - - -6 VLAN and Link Aggregation Support (IEEE 802.1, 802.1q, 802.3ad) -================================================================== - -The Marvell Yukon/SysKonnect Linux drivers are able to support VLAN and -Link Aggregation according to IEEE standards 802.1, 802.1q, and 802.3ad. -These features are only available after installation of open source -modules available on the Internet: -For VLAN go to: http://www.candelatech.com/~greear/vlan.html -For Link Aggregation go to: http://www.st.rim.or.jp/~yumo - -NOTE: SysKonnect GmbH does not offer any support for these open source - modules and does not take the responsibility for any kind of - failures or problems arising in connection with these modules. - -NOTE: Configuring Link Aggregation on a SysKonnect dual link adapter may - cause problems when unloading the driver. - - -7 Troubleshooting -================== - -If any problems occur during the installation process, check the -following list: - - -Problem: The SK-98xx adapter cannot be found by the driver. -Solution: In /proc/pci search for the following entry: - 'Ethernet controller: SysKonnect SK-98xx ...' - If this entry exists, the SK-98xx or SK-98xx V2.0 adapter has - been found by the system and should be operational. - If this entry does not exist or if the file '/proc/pci' is not - found, there may be a hardware problem or the PCI support may - not be enabled in your kernel. - The adapter can be checked using the diagnostics program which - is available on the SysKonnect web site: - www.syskonnect.com - - Some COMPAQ machines have problems dealing with PCI under Linux. - This problem is described in the 'PCI howto' document - (included in some distributions or available from the - web, e.g. at 'www.linux.org'). - - -Problem: Programs such as 'ifconfig' or 'route' cannot be found or the - error message 'Operation not permitted' is displayed. -Reason: You are not logged in as user 'root'. -Solution: Logout and login as 'root' or change to 'root' via 'su'. - - -Problem: Upon use of the command 'ping <address>' the message - "ping: sendto: Network is unreachable" is displayed. -Reason: Your route is not set correctly. -Solution: If you are using RedHat, you probably forgot to set up the - route in the 'network configuration'. - Check the existing routes with the 'route' command and check - if an entry for 'eth0' exists, and if so, if it is set correctly. - - -Problem: The driver can be started, the adapter is connected to the - network, but you cannot receive or transmit any packets; - e.g. 'ping' does not work. -Reason: There is an incorrect route in your routing table. -Solution: Check the routing table with the command 'route' and read the - manual help pages dealing with routes (enter 'man route'). - -NOTE: Although the 2.2.x kernel versions generate the routing entry - automatically, problems of this kind may occur here as well. We've - come across a situation in which the driver started correctly at - system start, but after the driver has been removed and reloaded, - the route of the adapter's network pointed to the 'dummy0'device - and had to be corrected manually. - - -Problem: Your computer should act as a router between multiple - IP subnetworks (using multiple adapters), but computers in - other subnetworks cannot be reached. -Reason: Either the router's kernel is not configured for IP forwarding - or the routing table and gateway configuration of at least one - computer is not working. - -Problem: Upon driver start, the following error message is displayed: - "eth0: -- ERROR -- - Class: internal Software error - Nr: 0xcc - Msg: SkGeInitPort() cannot init running ports" -Reason: You are using a driver compiled for single processor machines - on a multiprocessor machine with SMP (Symmetric MultiProcessor) - kernel. -Solution: Configure your kernel appropriately and recompile the kernel or - the modules. - - - -If your problem is not listed here, please contact SysKonnect's technical -support for help (linux@syskonnect.de). -When contacting our technical support, please ensure that the following -information is available: -- System Manufacturer and HW Informations (CPU, Memory... ) -- PCI-Boards in your system -- Distribution -- Kernel version -- Driver version -*** - - - -***End of Readme File*** diff --git a/Documentation/networking/spider_net.txt b/Documentation/networking/spider_net.txt new file mode 100644 index 000000000000..4b4adb8eb14f --- /dev/null +++ b/Documentation/networking/spider_net.txt @@ -0,0 +1,204 @@ + + The Spidernet Device Driver + =========================== + +Written by Linas Vepstas <linas@austin.ibm.com> + +Version of 7 June 2007 + +Abstract +======== +This document sketches the structure of portions of the spidernet +device driver in the Linux kernel tree. The spidernet is a gigabit +ethernet device built into the Toshiba southbridge commonly used +in the SONY Playstation 3 and the IBM QS20 Cell blade. + +The Structure of the RX Ring. +============================= +The receive (RX) ring is a circular linked list of RX descriptors, +together with three pointers into the ring that are used to manage its +contents. + +The elements of the ring are called "descriptors" or "descrs"; they +describe the received data. This includes a pointer to a buffer +containing the received data, the buffer size, and various status bits. + +There are three primary states that a descriptor can be in: "empty", +"full" and "not-in-use". An "empty" or "ready" descriptor is ready +to receive data from the hardware. A "full" descriptor has data in it, +and is waiting to be emptied and processed by the OS. A "not-in-use" +descriptor is neither empty or full; it is simply not ready. It may +not even have a data buffer in it, or is otherwise unusable. + +During normal operation, on device startup, the OS (specifically, the +spidernet device driver) allocates a set of RX descriptors and RX +buffers. These are all marked "empty", ready to receive data. This +ring is handed off to the hardware, which sequentially fills in the +buffers, and marks them "full". The OS follows up, taking the full +buffers, processing them, and re-marking them empty. + +This filling and emptying is managed by three pointers, the "head" +and "tail" pointers, managed by the OS, and a hardware current +descriptor pointer (GDACTDPA). The GDACTDPA points at the descr +currently being filled. When this descr is filled, the hardware +marks it full, and advances the GDACTDPA by one. Thus, when there is +flowing RX traffic, every descr behind it should be marked "full", +and everything in front of it should be "empty". If the hardware +discovers that the current descr is not empty, it will signal an +interrupt, and halt processing. + +The tail pointer tails or trails the hardware pointer. When the +hardware is ahead, the tail pointer will be pointing at a "full" +descr. The OS will process this descr, and then mark it "not-in-use", +and advance the tail pointer. Thus, when there is flowing RX traffic, +all of the descrs in front of the tail pointer should be "full", and +all of those behind it should be "not-in-use". When RX traffic is not +flowing, then the tail pointer can catch up to the hardware pointer. +The OS will then note that the current tail is "empty", and halt +processing. + +The head pointer (somewhat mis-named) follows after the tail pointer. +When traffic is flowing, then the head pointer will be pointing at +a "not-in-use" descr. The OS will perform various housekeeping duties +on this descr. This includes allocating a new data buffer and +dma-mapping it so as to make it visible to the hardware. The OS will +then mark the descr as "empty", ready to receive data. Thus, when there +is flowing RX traffic, everything in front of the head pointer should +be "not-in-use", and everything behind it should be "empty". If no +RX traffic is flowing, then the head pointer can catch up to the tail +pointer, at which point the OS will notice that the head descr is +"empty", and it will halt processing. + +Thus, in an idle system, the GDACTDPA, tail and head pointers will +all be pointing at the same descr, which should be "empty". All of the +other descrs in the ring should be "empty" as well. + +The show_rx_chain() routine will print out the the locations of the +GDACTDPA, tail and head pointers. It will also summarize the contents +of the ring, starting at the tail pointer, and listing the status +of the descrs that follow. + +A typical example of the output, for a nearly idle system, might be + +net eth1: Total number of descrs=256 +net eth1: Chain tail located at descr=20 +net eth1: Chain head is at 20 +net eth1: HW curr desc (GDACTDPA) is at 21 +net eth1: Have 1 descrs with stat=x40800101 +net eth1: HW next desc (GDACNEXTDA) is at 22 +net eth1: Last 255 descrs with stat=xa0800000 + +In the above, the hardware has filled in one descr, number 20. Both +head and tail are pointing at 20, because it has not yet been emptied. +Meanwhile, hw is pointing at 21, which is free. + +The "Have nnn decrs" refers to the descr starting at the tail: in this +case, nnn=1 descr, starting at descr 20. The "Last nnn descrs" refers +to all of the rest of the descrs, from the last status change. The "nnn" +is a count of how many descrs have exactly the same status. + +The status x4... corresponds to "full" and status xa... corresponds +to "empty". The actual value printed is RXCOMST_A. + +In the device driver source code, a different set of names are +used for these same concepts, so that + +"empty" == SPIDER_NET_DESCR_CARDOWNED == 0xa +"full" == SPIDER_NET_DESCR_FRAME_END == 0x4 +"not in use" == SPIDER_NET_DESCR_NOT_IN_USE == 0xf + + +The RX RAM full bug/feature +=========================== + +As long as the OS can empty out the RX buffers at a rate faster than +the hardware can fill them, there is no problem. If, for some reason, +the OS fails to empty the RX ring fast enough, the hardware GDACTDPA +pointer will catch up to the head, notice the not-empty condition, +ad stop. However, RX packets may still continue arriving on the wire. +The spidernet chip can save some limited number of these in local RAM. +When this local ram fills up, the spider chip will issue an interrupt +indicating this (GHIINT0STS will show ERRINT, and the GRMFLLINT bit +will be set in GHIINT1STS). When the RX ram full condition occurs, +a certain bug/feature is triggered that has to be specially handled. +This section describes the special handling for this condition. + +When the OS finally has a chance to run, it will empty out the RX ring. +In particular, it will clear the descriptor on which the hardware had +stopped. However, once the hardware has decided that a certain +descriptor is invalid, it will not restart at that descriptor; instead +it will restart at the next descr. This potentially will lead to a +deadlock condition, as the tail pointer will be pointing at this descr, +which, from the OS point of view, is empty; the OS will be waiting for +this descr to be filled. However, the hardware has skipped this descr, +and is filling the next descrs. Since the OS doesn't see this, there +is a potential deadlock, with the OS waiting for one descr to fill, +while the hardware is waiting for a different set of descrs to become +empty. + +A call to show_rx_chain() at this point indicates the nature of the +problem. A typical print when the network is hung shows the following: + +net eth1: Spider RX RAM full, incoming packets might be discarded! +net eth1: Total number of descrs=256 +net eth1: Chain tail located at descr=255 +net eth1: Chain head is at 255 +net eth1: HW curr desc (GDACTDPA) is at 0 +net eth1: Have 1 descrs with stat=xa0800000 +net eth1: HW next desc (GDACNEXTDA) is at 1 +net eth1: Have 127 descrs with stat=x40800101 +net eth1: Have 1 descrs with stat=x40800001 +net eth1: Have 126 descrs with stat=x40800101 +net eth1: Last 1 descrs with stat=xa0800000 + +Both the tail and head pointers are pointing at descr 255, which is +marked xa... which is "empty". Thus, from the OS point of view, there +is nothing to be done. In particular, there is the implicit assumption +that everything in front of the "empty" descr must surely also be empty, +as explained in the last section. The OS is waiting for descr 255 to +become non-empty, which, in this case, will never happen. + +The HW pointer is at descr 0. This descr is marked 0x4.. or "full". +Since its already full, the hardware can do nothing more, and thus has +halted processing. Notice that descrs 0 through 254 are all marked +"full", while descr 254 and 255 are empty. (The "Last 1 descrs" is +descr 254, since tail was at 255.) Thus, the system is deadlocked, +and there can be no forward progress; the OS thinks there's nothing +to do, and the hardware has nowhere to put incoming data. + +This bug/feature is worked around with the spider_net_resync_head_ptr() +routine. When the driver receives RX interrupts, but an examination +of the RX chain seems to show it is empty, then it is probable that +the hardware has skipped a descr or two (sometimes dozens under heavy +network conditions). The spider_net_resync_head_ptr() subroutine will +search the ring for the next full descr, and the driver will resume +operations there. Since this will leave "holes" in the ring, there +is also a spider_net_resync_tail_ptr() that will skip over such holes. + +As of this writing, the spider_net_resync() strategy seems to work very +well, even under heavy network loads. + + +The TX ring +=========== +The TX ring uses a low-watermark interrupt scheme to make sure that +the TX queue is appropriately serviced for large packet sizes. + +For packet sizes greater than about 1KBytes, the kernel can fill +the TX ring quicker than the device can drain it. Once the ring +is full, the netdev is stopped. When there is room in the ring, +the netdev needs to be reawakened, so that more TX packets are placed +in the ring. The hardware can empty the ring about four times per jiffy, +so its not appropriate to wait for the poll routine to refill, since +the poll routine runs only once per jiffy. The low-watermark mechanism +marks a descr about 1/4th of the way from the bottom of the queue, so +that an interrupt is generated when the descr is processed. This +interrupt wakes up the netdev, which can then refill the queue. +For large packets, this mechanism generates a relatively small number +of interrupts, about 1K/sec. For smaller packets, this will drop to zero +interrupts, as the hardware can empty the queue faster than the kernel +can fill it. + + + ======= END OF DOCUMENT ======== + |
