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* mpls: handle device renames for per-device sysctlsRobert Shearman2015-06-121-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a device is renamed and the original name is subsequently reused for a new device, the following warning is generated: sysctl duplicate entry: /net/mpls/conf/veth0//input CPU: 3 PID: 1379 Comm: ip Not tainted 4.1.0-rc4+ #20 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 0000000000000000 0000000000000000 ffffffff81566aaf 0000000000000000 ffffffff81236279 ffff88002f7d7f00 0000000000000000 ffff88000db336d8 ffff88000db33698 0000000000000005 ffff88002e046000 ffff8800168c9280 Call Trace: [<ffffffff81566aaf>] ? dump_stack+0x40/0x50 [<ffffffff81236279>] ? __register_sysctl_table+0x289/0x5a0 [<ffffffffa051a24f>] ? mpls_dev_notify+0x1ff/0x300 [mpls_router] [<ffffffff8108db7f>] ? notifier_call_chain+0x4f/0x70 [<ffffffff81470e72>] ? register_netdevice+0x2b2/0x480 [<ffffffffa0524748>] ? veth_newlink+0x178/0x2d3 [veth] [<ffffffff8147f84c>] ? rtnl_newlink+0x73c/0x8e0 [<ffffffff8147f27a>] ? rtnl_newlink+0x16a/0x8e0 [<ffffffff81459ff2>] ? __kmalloc_reserve.isra.30+0x32/0x90 [<ffffffff8147ccfd>] ? rtnetlink_rcv_msg+0x8d/0x250 [<ffffffff8145b027>] ? __alloc_skb+0x47/0x1f0 [<ffffffff8149badb>] ? __netlink_lookup+0xab/0xe0 [<ffffffff8147cc70>] ? rtnetlink_rcv+0x30/0x30 [<ffffffff8149e7a0>] ? netlink_rcv_skb+0xb0/0xd0 [<ffffffff8147cc64>] ? rtnetlink_rcv+0x24/0x30 [<ffffffff8149df17>] ? netlink_unicast+0x107/0x1a0 [<ffffffff8149e4be>] ? netlink_sendmsg+0x50e/0x630 [<ffffffff8145209c>] ? sock_sendmsg+0x3c/0x50 [<ffffffff81452beb>] ? ___sys_sendmsg+0x27b/0x290 [<ffffffff811bd258>] ? mem_cgroup_try_charge+0x88/0x110 [<ffffffff811bd5b6>] ? mem_cgroup_commit_charge+0x56/0xa0 [<ffffffff811d7700>] ? do_filp_open+0x30/0xa0 [<ffffffff8145336e>] ? __sys_sendmsg+0x3e/0x80 [<ffffffff8156c3f2>] ? system_call_fastpath+0x16/0x75 Fix this by unregistering the previous sysctl table (registered for the path containing the original device name) and re-registering the table for the path containing the new device name. Fixes: 37bde79979c3 ("mpls: Per-device enabling of packet input") Reported-by: Scott Feldman <sfeldma@gmail.com> Signed-off-by: Robert Shearman <rshearma@brocade.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: fix possible use after free of deviceRobert Shearman2015-06-082-1/+2
| | | | | | | | | | | | | | The mpls device is used in an RCU read context without a lock being held. As the memory is freed without waiting for the RCU grace period to elapse, the freed memory could still be in use. Address this by using kfree_rcu to free the memory for the mpls device after the RCU grace period has elapsed. Fixes: 03c57747a702 ("mpls: Per-device MPLS state") Signed-off-by: Robert Shearman <rshearma@brocade.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Change reserved label names to be consistent with netbsdTom Herbert2015-05-101-9/+9
| | | | | | | | Since these are now visible to userspace it is nice to be consistent with BSD (sys/netmpls/mpls.h in netBSD). Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Move reserved label definitionsTom Herbert2015-05-062-19/+9
| | | | | | | Move to include/uapi/linux/mpls.h to be externally visibile. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Prevent use of implicit NULL label as outgoing labelRobert Shearman2015-04-221-0/+9
| | | | | | | | | | | The reserved implicit-NULL label isn't allowed to appear in the label stack for packets, so make it an error for the control plane to specify it as an outgoing label. Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Robert Shearman <rshearma@brocade.com> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Per-device enabling of packet inputRobert Shearman2015-04-222-2/+69
| | | | | | | | | | | | | | | | | | | | | | An MPLS network is a single trust domain where the edges must be in control of what labels make their way into the core. The simplest way of ensuring this is for the edge device to always impose the labels, and not allow forward labeled traffic from untrusted neighbours. This is achieved by allowing a per-device configuration of whether MPLS traffic input from that interface should be processed or not. To be secure by default, the default state is changed to MPLS being disabled on all interfaces unless explicitly enabled and no global option is provided to change the default. Whilst this differs from other protocols (e.g. IPv6), network operators are used to explicitly enabling MPLS forwarding on interfaces, and with the number of links to the MPLS core typically fairly low this doesn't present too much of a burden on operators. Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Robert Shearman <rshearma@brocade.com> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Per-device MPLS stateRobert Shearman2015-04-222-2/+51
| | | | | | | | | | | | | | Add per-device MPLS state to supported interfaces. Use the presence of this state in mpls_route_add to determine that this is a supported interface. Use the presence of mpls_dev to drop packets that arrived on an unsupported interface - previously they were allowed through. Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Robert Shearman <rshearma@brocade.com> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: In mpls_egress verify the packet length.Eric W. Biederman2015-03-131-1/+16
| | | | | | | | | | | | | Reobert Shearman noticed that mpls_egress is failing to verify that the bytes to be examined are in fact present in the packet before mpls_egress reads those bytes. As suggested by David Miller reduce this to a single pskb_may_pull call so that we don't do unnecessary work in the fast path. Reported-by: Robert Shearman <rshearma@brocade.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Allow mpls_gso and mpls_router to be built as modulesRobert Shearman2015-03-112-4/+6
| | | | | | | | | | | | | CONFIG_MPLS=m doesn't result in a kernel module being built because it applies to the net/mpls directory, rather than to .o files. So revert the MPLS menuitem to being a boolean and make MPLS_GSO and MPLS_ROUTING tristates to allow mpls_gso and mpls_router modules to be produced as desired. Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Robert Shearman <rshearma@brocade.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Spelling: s/conceved/conceived/, s/as/a/Geert Uytterhoeven2015-03-091-2/+2
| | | | | | Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* neigh: Use neigh table index for neigh_packet_xmitEric W. Biederman2015-03-091-13/+22
| | | | | | | | | Remove a little bit of unnecessary work when transmitting a packet with neigh_packet_xmit. Use the neighbour table index not the address family as a parameter. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Correct the ttl decrement.Eric W. Biederman2015-03-091-1/+1
| | | | | | | | | | | | According to RFC3032 section 2.4.2 packets with an outgoing ttl of 0 MUST NOT be forwarded. According to section 2.4.1 an outgoing TTL of 0 comes from an incomming TTL <= 1. Therefore any packets that is received with a ttl <= 1 should not have it's ttl decremented and forwarded. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Better error code for unsupported option.Eric W. Biederman2015-03-091-1/+1
| | | | | Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Cleanup the rcu usage in the code.Eric W. Biederman2015-03-091-26/+47
| | | | | | | | | | | | | | | Sparse was generating a lot of warnings mostly from missing annotations in the code. Add missing annotations and in a few cases tweak the code for performance by moving work before loops. This also fixes a problematic ommision of rcu_assign_pointer and rcu_dereference. Hopefully with complete rcu annotations any new rcu errors will stick out like a sore thumb. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Fix the kzalloc argument order in mpls_rt_allocEric W. Biederman2015-03-091-1/+1
| | | | | | | | | | *Blink* I got the argument order wrong to kzalloc and the code was working properly when tested. *Blink* Fix that. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Properly validate RTA_VIA payload lengthRobert Shearman2015-03-061-1/+4
| | | | | | | | | | | | | If the nla length is less than 2 then the nla data could be accessed beyond the accessible bounds. So ensure that the nla is big enough to at least read the via_family before doing so. Replace magic value of 2. Fixes: 03c0566542f4 ("mpls: Basic support for adding and removing routes") Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Robert Shearman <rshearma@brocade.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: using vzalloc requires including vmalloc.hStephen Rothwell2015-03-061-0/+1
| | | | | | | | | | | | | Fixes this build error: net/mpls/af_mpls.c: In function 'resize_platform_label_table': net/mpls/af_mpls.c:767:4: error: implicit declaration of function 'vzalloc' [-Werror=implicit-function-declaration] labels = vzalloc(size); ^ Fixes: 7720c01f3f59 ("mpls: Add a sysctl to control the size of the mpls label table") Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: rtm_mpls_policy[] can be staticWu Fengguang2015-03-041-1/+1
| | | | | Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Multicast route table change notificationsEric W. Biederman2015-03-041-0/+60
| | | | | | | | | | | | | | Unlike IPv4 this code notifies on all cases where mpls routes are added or removed and it never automatically removes routes. Avoiding both the userspace confusion that is caused by omitting route updates and the possibility of a flood of netlink traffic when an interface goes doew. For now reserved labels are handled automatically and userspace is not notified. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Netlink commands to add, remove, and dump routesEric W. Biederman2015-03-041-0/+229
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change adds two new netlink routing attributes: RTA_VIA and RTA_NEWDST. RTA_VIA specifies the specifies the next machine to send a packet to like RTA_GATEWAY. RTA_VIA differs from RTA_GATEWAY in that it includes the address family of the address of the next machine to send a packet to. Currently the MPLS code supports addresses in AF_INET, AF_INET6 and AF_PACKET. For AF_INET and AF_INET6 the destination mac address is acquired from the neighbour table. For AF_PACKET the destination mac_address is specified in the netlink configuration. I think raw destination mac address support with the family AF_PACKET will prove useful. There is MPLS-TP which is defined to operate on machines that do not support internet packets of any flavor. Further seem to be corner cases where it can be useful. At this point I don't care much either way. RTA_NEWDST specifies the destination address to forward the packet with. MPLS typically changes it's destination address at every hop. For a swap operation RTA_NEWDST is specified with a length of one label. For a push operation RTA_NEWDST is specified with two or more labels. For a pop operation RTA_NEWDST is not specified or equivalently an emtpy RTAN_NEWDST is specified. Those new netlink attributes are used to implement handling of rt-netlink RTM_NEWROUTE, RTM_DELROUTE, and RTM_GETROUTE messages, to maintain the MPLS label table. rtm_to_route_config parses a netlink RTM_NEWROUTE or RTM_DELROUTE message, verify no unhandled attributes or unhandled values are present and sets up the data structures for mpls_route_add and mpls_route_del. I did my best to match up with the existing conventions with the caveats that MPLS addresses are all destination-specific-addresses, and so don't properly have a scope. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Functions for reading and wrinting mpls labels over netlinkEric W. Biederman2015-03-042-0/+60
| | | | | | | | | | | | | | | | | | | Reading and writing addresses in network byte order in netlink is traditional and I see no reason to change that. MPLS is interesting as effectively it has variabely length addresses (the MPLS label stack). To represent these variable length addresses in netlink I use a valid MPLS label stack (complete with stop bit). This achieves two things: a well defined existing format is used, and the data can be interpreted without looking at it's length. Not needed to look at the length to decode the variable length network representation allows existing userspace functions such as inet_ntop to be used without needed to change their prototype. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Basic support for adding and removing routesEric W. Biederman2015-03-041-0/+133
| | | | | | | | | | | | | | | | | | | | | | | | mpls_route_add and mpls_route_del implement the basic logic for adding and removing Next Hop Label Forwarding Entries from the MPLS input label map. The addition and subtraction is done in a way that is consistent with how the existing routing table in Linux are maintained. Thus all of the work to deal with NLM_F_APPEND, NLM_F_EXCL, NLM_F_REPLACE, and NLM_F_CREATE. Cases that are not clearly defined such as changing the interpretation of the mpls reserved labels is not allowed. Because it seems like the right thing to do adding an MPLS route without specifying an input label and allowing the kernel to pick a free label table entry is supported. The implementation is currently less than optimal but that can be changed. As I don't have anything else to test with only ethernet and the loopback device are the only two device types currently supported for forwarding MPLS over. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Add a sysctl to control the size of the mpls label tableEric W. Biederman2015-03-041-0/+146
| | | | | | | | | | | | | | | | This sysctl gives two benefits. By defaulting the table size to 0 mpls even when compiled in and enabled defaults to not forwarding any packets. This prevents unpleasant surprises for users. The other benefit is that as mpls labels are allocated locally a dense table a small dense label table may be used which saves memory and is extremely simple and efficient to implement. This sysctl allows userspace to choose the restrictions on the label table size userspace applications need to cope with. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Basic routing supportEric W. Biederman2015-03-044-0/+411
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change adds a new Kconfig option MPLS_ROUTING. The core of this change is the code to look at an mpls packet received from another machine. Look that packet up in a routing table and forward the packet on. Support of MPLS over ATM is not considered or attempted here. This implemntation follows RFC3032 and implements the MPLS shim header that can pass over essentially any network. What RFC3021 refers to as the as the Incoming Label Map (ILM) I call net->mpls.platform_label[]. What RFC3031 refers to as the Next Label Hop Forwarding Entry (NHLFE) I call mpls_route. Though calling it the label fordwarding information base (lfib) might also be valid. Further the implemntation forwards packets as described in RFC3032. There is no need and given the original motivation for MPLS a strong discincentive to have a flexible label forwarding path. In essence the logic is the topmost label is read, looked up, removed, and replaced by 0 or more new lables and the sent out the specified interface to it's next hop. Quite a few optional features are not implemented here. Among them are generation of ICMP errors when the TTL is exceeded or the packet is larger than the next hop MTU (those conditions are detected and the packets are dropped instead of generating an icmp error). The traffic class field is always set to 0. The implementation focuses on IP over MPLS and does not handle egress of other kinds of protocols. Instead of implementing coordination with the neighbour table and sorting out how to input next hops in a different address family (for which there is value). I was lazy and implemented a next hop mac address instead. The code is simpler and there are flavor of MPLS such as MPLS-TP where neither an IPv4 nor an IPv6 next hop is appropriate so a next hop by mac address would need to be implemented at some point. Two new definitions AF_MPLS and PF_MPLS are exposed to userspace. Decoding the mpls header must be done by first byeswapping a 32bit bit endian word into the local cpu endian and then bit shifting to extract the pieces. There is no C bit-field that can represent a wire format mpls header on a little endian machine as the low bits of the 20bit label wind up in the wrong half of third byte. Therefore internally everything is deal with in cpu native byte order except when writing to and reading from a packet. For management simplicity if a label is configured to forward out an interface that is down the packet is dropped early. Similarly if an network interface is removed rt_dev is updated to NULL (so no reference is preserved) and any packets for that label are dropped. Keeping the label entries in the kernel allows the kernel label table to function as the definitive source of which labels are allocated and which are not. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Refactor how the mpls module is builtEric W. Biederman2015-03-041-1/+17
| | | | | | | | | This refactoring is needed to allow more than just mpls gso support to be built into the mpls moddule. Reviewed-by: Simon Horman <horms@verge.net.au> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: mark some potential candidates __read_mostlyDaniel Borkmann2015-01-311-2/+2
| | | | | | | | They are all either written once or extremly rarely (e.g. from init code), so we can move them to the .data..read_mostly section. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Fix allowed protocols for mpls gsoPravin B Shelar2014-12-241-4/+1
| | | | | | | | | MPLS and Tunnel GSO does not work together. Reject packet which request such GSO. Fixes: 0d89d2035f ("MPLS: Add limited GSO support"). Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Remove MPLS GSO feature.Pravin B Shelar2014-11-061-2/+1
| | | | | | | | Device can export MPLS GSO support in dev->mpls_features same way it export vlan features in dev->vlan_features. So it is safe to remove NETIF_F_GSO_MPLS redundant flag. Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
* mpls: Allow mpls_gso to be built as modulePravin B Shelar2014-10-311-1/+1
| | | | | | | | | | Kconfig already allows mpls to be built as module. Following patch fixes Makefile to do same. CC: Simon Horman <simon.horman@netronome.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* mpls: Fix mpls_gso handler.Pravin B Shelar2014-10-311-2/+1
| | | | | | | | | mpls gso handler needs to pull skb after segmenting skb. CC: Simon Horman <simon.horman@netronome.com> Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: gso: use feature flag argument in all protocol gso handlersFlorian Westphal2014-10-201-1/+1
| | | | | | | | | | | | | | | | | | | | skb_gso_segment() has a 'features' argument representing offload features available to the output path. A few handlers, e.g. GRE, instead re-fetch the features of skb->dev and use those instead of the provided ones when handing encapsulation/tunnels. Depending on dev->hw_enc_features of the output device skb_gso_segment() can then return NULL even when the caller has disabled all GSO feature bits, as segmentation of inner header thinks device will take care of segmentation. This e.g. affects the tbf scheduler, which will silently drop GRE-encap GSO skbs that did not fit the remaining token quota as the segmentation does not work when device supports corresponding hw offload capabilities. Cc: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Remove gso_send_check as an offload callbackTom Herbert2014-09-261-7/+0
| | | | | | | | | | The send_check logic was only interesting in cases of TCP offload and UDP UFO where the checksum needed to be initialized to the pseudo header checksum. Now we've moved that logic into the related gso_segment functions so gso_send_check is no longer needed. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* gre: Call gso_make_checksumTom Herbert2014-06-051-0/+1
| | | | | | | | | | | Call gso_make_checksum. This should have the benefit of using a checksum that may have been previously computed for the packet. This also adds NETIF_F_GSO_GRE_CSUM to differentiate devices that offload GRE GSO with and without the GRE checksum offloaed. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* ipip: add GSO/TSO supportEric Dumazet2013-10-201-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now inet_gso_segment() is stackable, its relatively easy to implement GSO/TSO support for IPIP Performance results, when segmentation is done after tunnel device (as no NIC is yet enabled for TSO IPIP support) : Before patch : lpq83:~# ./netperf -H 7.7.9.84 -Cc MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 87380 16384 16384 10.00 3357.88 5.09 3.70 2.983 2.167 After patch : lpq83:~# ./netperf -H 7.7.9.84 -Cc MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 87380 16384 16384 10.00 7710.19 4.52 6.62 1.152 1.687 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* MPLS: Add limited GSO supportSimon Horman2013-05-283-0/+121
In the case where a non-MPLS packet is received and an MPLS stack is added it may well be the case that the original skb is GSO but the NIC used for transmit does not support GSO of MPLS packets. The aim of this code is to provide GSO in software for MPLS packets whose skbs are GSO. SKB Usage: When an implementation adds an MPLS stack to a non-MPLS packet it should do the following to skb metadata: * Set skb->inner_protocol to the old non-MPLS ethertype of the packet. skb->inner_protocol is added by this patch. * Set skb->protocol to the new MPLS ethertype of the packet. * Set skb->network_header to correspond to the end of the L3 header, including the MPLS label stack. I have posted a patch, "[PATCH v3.29] datapath: Add basic MPLS support to kernel" which adds MPLS support to the kernel datapath of Open vSwtich. That patch sets the above requirements in datapath/actions.c:push_mpls() and was used to exercise this code. The datapath patch is against the Open vSwtich tree but it is intended that it be added to the Open vSwtich code present in the mainline Linux kernel at some point. Features: I believe that the approach that I have taken is at least partially consistent with the handling of other protocols. Jesse, I understand that you have some ideas here. I am more than happy to change my implementation. This patch adds dev->mpls_features which may be used by devices to advertise features supported for MPLS packets. A new NETIF_F_MPLS_GSO feature is added for devices which support hardware MPLS GSO offload. Currently no devices support this and MPLS GSO always falls back to software. Alternate Implementation: One possible alternate implementation is to teach netif_skb_features() and skb_network_protocol() about MPLS, in a similar way to their understanding of VLANs. I believe this would avoid the need for net/mpls/mpls_gso.c and in particular the calls to __skb_push() and __skb_push() in mpls_gso_segment(). I have decided on the implementation in this patch as it should not introduce any overhead in the case where mpls_gso is not compiled into the kernel or inserted as a module. MPLS GSO suggested by Jesse Gross. Based in part on "v4 GRE: Add TCP segmentation offload for GRE" by Pravin B Shelar. Cc: Jesse Gross <jesse@nicira.com> Cc: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: Simon Horman <horms@verge.net.au> Signed-off-by: David S. Miller <davem@davemloft.net>
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