From e06e7c615877026544ad7f8b309d1a3706410383 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sun, 10 Jun 2007 17:22:39 -0700 Subject: [IPV4]: The scheduled removal of multipath cached routing support. With help from Chris Wedgwood. Signed-off-by: David S. Miller --- Documentation/feature-removal-schedule.txt | 19 ------------------- 1 file changed, 19 deletions(-) (limited to 'Documentation') diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 3a159dac04f..484250dcdbe 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -262,25 +262,6 @@ Who: Richard Purdie --------------------------- -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 - ---------------------------- - What: read_dev_chars(), read_conf_data{,_lpm}() (s390 common I/O layer) When: December 2007 Why: These functions are a leftover from 2.4 times. They have several -- cgit v1.2.3 From 58e50a904ec78caf4ca938801c031413b0d3f962 Mon Sep 17 00:00:00 2001 From: James Chapman Date: Wed, 27 Jun 2007 15:53:49 -0700 Subject: [L2TP]: Add PPPoL2TP in-kernel documentation Signed-off-by: James Chapman Signed-off-by: David S. Miller --- Documentation/networking/l2tp.txt | 169 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 Documentation/networking/l2tp.txt (limited to 'Documentation') diff --git a/Documentation/networking/l2tp.txt b/Documentation/networking/l2tp.txt new file mode 100644 index 00000000000..2451f551c50 --- /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. -- cgit v1.2.3 From a093bf006e09a305e95ff0938c0a18b7520aef67 Mon Sep 17 00:00:00 2001 From: Peter P Waskiewicz Jr Date: Thu, 28 Jun 2007 20:45:47 -0700 Subject: [NET]: [DOC] Multiqueue hardware support documentation Add a brief howto to Documentation/networking for multiqueue. It explains how to use the multiqueue API in a driver to support multiqueue paths from the stack, as well as the qdiscs to use for feeding a multiqueue device. Signed-off-by: Peter P Waskiewicz Jr Signed-off-by: David S. Miller --- Documentation/networking/multiqueue.txt | 111 ++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 Documentation/networking/multiqueue.txt (limited to 'Documentation') diff --git a/Documentation/networking/multiqueue.txt b/Documentation/networking/multiqueue.txt new file mode 100644 index 00000000000..00b60cce222 --- /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. -- cgit v1.2.3 From 3569b621ceba0a9cfb80e24c0bd19fd632ccee25 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Sat, 7 Jul 2007 22:38:07 -0700 Subject: [NETFILTER]: ipt_SAME: add to feature-removal-schedule Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- Documentation/feature-removal-schedule.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 484250dcdbe..062fc2e79c8 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -311,3 +311,11 @@ Who: Tejun Heo --------------------------- +What: iptables SAME target +When: 1.1. 2008 +Files: net/ipv4/netfilter/ipt_SAME.c, include/linux/netfilter_ipv4/ipt_SAME.h +Why: Obsolete for multiple years now, NAT core provides the same behaviour. + Unfixable broken wrt. 32/64 bit cleanness. +Who: Patrick McHardy + +--------------------------- -- cgit v1.2.3 From 1722933323b70f44b0548131604f1f3454c2aa8f Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sat, 7 Jul 2007 22:59:14 -0700 Subject: [NET]: netdevice locking assumptions documentation Update the documentation about locking assumptions. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- Documentation/networking/netdevices.txt | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt index ce1361f9524..a6cab674b67 100644 --- a/Documentation/networking/netdevices.txt +++ b/Documentation/networking/netdevices.txt @@ -20,7 +20,6 @@ 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. - struct net_device synchronization rules ======================================= dev->open: @@ -43,16 +42,17 @@ 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 +74,5 @@ 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. -- cgit v1.2.3 From 1c8c7d64169dc4b1ae3d8cd1bf35ea0a099b50ad Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sat, 7 Jul 2007 23:03:44 -0700 Subject: [NET]: netdevice mtu assumptions documentation Document the expectations about device MTU handling. The documentation about oversize packet handling is probably too loose. IMHO devices should drop oversize packets for robustness, but many devices allow it now. For example, if you set mtu to 1200 bytes, most ether devices will allow a 1500 byte frame in. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- Documentation/networking/netdevices.txt | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'Documentation') diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt index a6cab674b67..37869295fc7 100644 --- a/Documentation/networking/netdevices.txt +++ b/Documentation/networking/netdevices.txt @@ -20,6 +20,31 @@ 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 ======================================= dev->open: -- cgit v1.2.3 From bb4dbf9e61d0801927e7df2569bb3dd8287ea301 Mon Sep 17 00:00:00 2001 From: YOSHIFUJI Hideaki Date: Tue, 10 Jul 2007 22:55:49 -0700 Subject: [IPV6]: Do not send RH0 anymore. Based on . Signed-off-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index af6a63ab902..09c184e41cf 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -874,8 +874,7 @@ 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 -- cgit v1.2.3