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2018-06-11xsk: silence warning on memory allocation failureBjörn Töpel
syzkaller reported a warning from xdp_umem_pin_pages(): WARNING: CPU: 1 PID: 4537 at mm/slab_common.c:996 kmalloc_slab+0x56/0x70 mm/slab_common.c:996 ... __do_kmalloc mm/slab.c:3713 [inline] __kmalloc+0x25/0x760 mm/slab.c:3727 kmalloc_array include/linux/slab.h:634 [inline] kcalloc include/linux/slab.h:645 [inline] xdp_umem_pin_pages net/xdp/xdp_umem.c:205 [inline] xdp_umem_reg net/xdp/xdp_umem.c:318 [inline] xdp_umem_create+0x5c9/0x10f0 net/xdp/xdp_umem.c:349 xsk_setsockopt+0x443/0x550 net/xdp/xsk.c:531 __sys_setsockopt+0x1bd/0x390 net/socket.c:1935 __do_sys_setsockopt net/socket.c:1946 [inline] __se_sys_setsockopt net/socket.c:1943 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1943 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe This is a warning about attempting to allocate more than KMALLOC_MAX_SIZE memory. The request originates from userspace, and if the request is too big, the kernel is free to deny its allocation. In this patch, the failed allocation attempt is silenced with __GFP_NOWARN. Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Reported-by: syzbot+4abadc5d69117b346506@syzkaller.appspotmail.com Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-07bpf, xdp: fix crash in xdp_umem_unaccount_pagesDaniel Borkmann
syzkaller was able to trigger the following panic for AF_XDP: BUG: KASAN: null-ptr-deref in atomic64_sub include/asm-generic/atomic-instrumented.h:144 [inline] BUG: KASAN: null-ptr-deref in atomic_long_sub include/asm-generic/atomic-long.h:199 [inline] BUG: KASAN: null-ptr-deref in xdp_umem_unaccount_pages.isra.4+0x3d/0x80 net/xdp/xdp_umem.c:135 Write of size 8 at addr 0000000000000060 by task syz-executor246/4527 CPU: 1 PID: 4527 Comm: syz-executor246 Not tainted 4.17.0+ #89 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 kasan_report_error mm/kasan/report.c:352 [inline] kasan_report.cold.7+0x6d/0x2fe mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278 atomic64_sub include/asm-generic/atomic-instrumented.h:144 [inline] atomic_long_sub include/asm-generic/atomic-long.h:199 [inline] xdp_umem_unaccount_pages.isra.4+0x3d/0x80 net/xdp/xdp_umem.c:135 xdp_umem_reg net/xdp/xdp_umem.c:334 [inline] xdp_umem_create+0xd6c/0x10f0 net/xdp/xdp_umem.c:349 xsk_setsockopt+0x443/0x550 net/xdp/xsk.c:531 __sys_setsockopt+0x1bd/0x390 net/socket.c:1935 __do_sys_setsockopt net/socket.c:1946 [inline] __se_sys_setsockopt net/socket.c:1943 [inline] __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1943 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe In xdp_umem_reg() the call to xdp_umem_account_pages() passed with CAP_IPC_LOCK where we didn't need to end up charging rlimit on memlock for the current user and therefore umem->user continues to be NULL. Later on through fault injection syzkaller triggered a failure in either umem->pgs or umem->pages allocation such that we bail out and undo accounting in xdp_umem_unaccount_pages() where we eventually hit the panic since it tries to deref the umem->user. The code is pretty close to mm_account_pinned_pages() and mm_unaccount_pinned_pages() pair and potentially could reuse it even in a later cleanup, and it appears that the initial commit c0c77d8fb787 ("xsk: add user memory registration support sockopt") got this right while later follow-up introduced the bug via a49049ea2576 ("xsk: simplified umem setup"). Fixes: a49049ea2576 ("xsk: simplified umem setup") Reported-by: syzbot+979217770b09ebf5c407@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-06-08xsk: Fix umem fill/completion queue mmap on 32-bitGeert Uytterhoeven
With gcc-4.1.2 on 32-bit: net/xdp/xsk.c:663: warning: integer constant is too large for ‘long’ type net/xdp/xsk.c:665: warning: integer constant is too large for ‘long’ type Add the missing "ULL" suffixes to the large XDP_UMEM_PGOFF_*_RING values to fix this. net/xdp/xsk.c:663: warning: comparison is always false due to limited range of data type net/xdp/xsk.c:665: warning: comparison is always false due to limited range of data type "unsigned long" is 32-bit on 32-bit systems, hence the offset is truncated, and can never be equal to any of the XDP_UMEM_PGOFF_*_RING values. Use loff_t (and the required cast) to fix this. Fixes: 423f38329d267969 ("xsk: add umem fill queue support and mmap") Fixes: fe2308328cd2f26e ("xsk: add umem completion queue support and mmap") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds
Pull networking updates from David Miller: 1) Add Maglev hashing scheduler to IPVS, from Inju Song. 2) Lots of new TC subsystem tests from Roman Mashak. 3) Add TCP zero copy receive and fix delayed acks and autotuning with SO_RCVLOWAT, from Eric Dumazet. 4) Add XDP_REDIRECT support to mlx5 driver, from Jesper Dangaard Brouer. 5) Add ttl inherit support to vxlan, from Hangbin Liu. 6) Properly separate ipv6 routes into their logically independant components. fib6_info for the routing table, and fib6_nh for sets of nexthops, which thus can be shared. From David Ahern. 7) Add bpf_xdp_adjust_tail helper, which can be used to generate ICMP messages from XDP programs. From Nikita V. Shirokov. 8) Lots of long overdue cleanups to the r8169 driver, from Heiner Kallweit. 9) Add BTF ("BPF Type Format"), from Martin KaFai Lau. 10) Add traffic condition monitoring to iwlwifi, from Luca Coelho. 11) Plumb extack down into fib_rules, from Roopa Prabhu. 12) Add Flower classifier offload support to igb, from Vinicius Costa Gomes. 13) Add UDP GSO support, from Willem de Bruijn. 14) Add documentation for eBPF helpers, from Quentin Monnet. 15) Add TLS tx offload to mlx5, from Ilya Lesokhin. 16) Allow applications to be given the number of bytes available to read on a socket via a control message returned from recvmsg(), from Soheil Hassas Yeganeh. 17) Add x86_32 eBPF JIT compiler, from Wang YanQing. 18) Add AF_XDP sockets, with zerocopy support infrastructure as well. From Björn Töpel. 19) Remove indirect load support from all of the BPF JITs and handle these operations in the verifier by translating them into native BPF instead. From Daniel Borkmann. 20) Add GRO support to ipv6 gre tunnels, from Eran Ben Elisha. 21) Allow XDP programs to do lookups in the main kernel routing tables for forwarding. From David Ahern. 22) Allow drivers to store hardware state into an ELF section of kernel dump vmcore files, and use it in cxgb4. From Rahul Lakkireddy. 23) Various RACK and loss detection improvements in TCP, from Yuchung Cheng. 24) Add TCP SACK compression, from Eric Dumazet. 25) Add User Mode Helper support and basic bpfilter infrastructure, from Alexei Starovoitov. 26) Support ports and protocol values in RTM_GETROUTE, from Roopa Prabhu. 27) Support bulking in ->ndo_xdp_xmit() API, from Jesper Dangaard Brouer. 28) Add lots of forwarding selftests, from Petr Machata. 29) Add generic network device failover driver, from Sridhar Samudrala. * ra.kernel.org:/pub/scm/linux/kernel/git/davem/net-next: (1959 commits) strparser: Add __strp_unpause and use it in ktls. rxrpc: Fix terminal retransmission connection ID to include the channel net: hns3: Optimize PF CMDQ interrupt switching process net: hns3: Fix for VF mailbox receiving unknown message net: hns3: Fix for VF mailbox cannot receiving PF response bnx2x: use the right constant Revert "net: sched: cls: Fix offloading when ingress dev is vxlan" net: dsa: b53: Fix for brcm tag issue in Cygnus SoC enic: fix UDP rss bits netdev-FAQ: clarify DaveM's position for stable backports rtnetlink: validate attributes in do_setlink() mlxsw: Add extack messages for port_{un, }split failures netdevsim: Add extack error message for devlink reload devlink: Add extack to reload and port_{un, }split operations net: metrics: add proper netlink validation ipmr: fix error path when ipmr_new_table fails ip6mr: only set ip6mr_table from setsockopt when ip6mr_new_table succeeds net: hns3: remove unused hclgevf_cfg_func_mta_filter netfilter: provide udp*_lib_lookup for nf_tproxy qed*: Utilize FW 8.37.2.0 ...
2018-06-05xsk: wire upp Tx zero-copy functionsMagnus Karlsson
Here we add the functionality required to support zero-copy Tx, and also exposes various zero-copy related functions for the netdevs. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-05xsk: add zero-copy support for RxBjörn Töpel
Extend the xsk_rcv to support the new MEM_TYPE_ZERO_COPY memory, and wireup ndo_bpf call in bind. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-05xsk: introduce xdp_umem_pageBjörn Töpel
The xdp_umem_page holds the address for a page. Trade memory for faster lookup. Later, we'll add DMA address here as well. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-05xsk: moved struct xdp_umem definitionBjörn Töpel
Moved struct xdp_umem to xdp_sock.h, in order to prepare for zero-copy support. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-04xsk: new descriptor addressing schemeBjörn Töpel
Currently, AF_XDP only supports a fixed frame-size memory scheme where each frame is referenced via an index (idx). A user passes the frame index to the kernel, and the kernel acts upon the data. Some NICs, however, do not have a fixed frame-size model, instead they have a model where a memory window is passed to the hardware and multiple frames are filled into that window (referred to as the "type-writer" model). By changing the descriptor format from the current frame index addressing scheme, AF_XDP can in the future be extended to support these kinds of NICs. In the index-based model, an idx refers to a frame of size frame_size. Addressing a frame in the UMEM is done by offseting the UMEM starting address by a global offset, idx * frame_size + offset. Communicating via the fill- and completion-rings are done by means of idx. In this commit, the idx is removed in favor of an address (addr), which is a relative address ranging over the UMEM. To convert an idx-based address to the new addr is simply: addr = idx * frame_size + offset. We also stop referring to the UMEM "frame" as a frame. Instead it is simply called a chunk. To transfer ownership of a chunk to the kernel, the addr of the chunk is passed in the fill-ring. Note, that the kernel will mask addr to make it chunk aligned, so there is no need for userspace to do that. E.g., for a chunk size of 2k, passing an addr of 2048, 2050 or 3000 to the fill-ring will refer to the same chunk. On the completion-ring, the addr will match that of the Tx descriptor, passed to the kernel. Changing the descriptor format to use chunks/addr will allow for future changes to move to a type-writer based model, where multiple frames can reside in one chunk. In this model passing one single chunk into the fill-ring, would potentially result in multiple Rx descriptors. This commit changes the uapi of AF_XDP sockets, and updates the documentation. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-04xsk: proper Rx drop statistics updateBjörn Töpel
Previously, rx_dropped could be updated incorrectly, e.g. if the XDP program redirected the frame to a socket bound to a different queue than where the XDP program was executing. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-04xsk: proper fill queue descriptor validationBjörn Töpel
Previously the fill queue descriptor was not copied to kernel space prior validating it, making it possible for userland to change the descriptor post-kernel-validation. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-22xsk: convert atomic_t to refcount_tBjörn Töpel
Introduce refcount_t, in favor of atomic_t. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-22xsk: simplified umem setupBjörn Töpel
As suggested by Daniel Borkmann, the umem setup code was a too defensive and complex. Here, we reduce the number of checks. Also, the memory pinning is now folded into the umem creation, and we do correct locking. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-22xsk: add missing write- and data-dependency barrierBjörn Töpel
Here, we add a missing write-barrier, and use READ_ONCE for the data-dependency barrier. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-22xsk: remove explicit ring structure from uapiBjörn Töpel
In this commit we remove the explicit ring structure from the the uapi. It is tricky for an uapi to depend on a certain L1 cache line size, since it can differ for variants of the same architecture. Now, we let the user application determine the offsets of the producer, consumer and descriptors by asking the socket via getsockopt. A typical flow would be (Rx ring): struct xdp_mmap_offsets off; struct xdp_desc *ring; u32 *prod, *cons; void *map; ... getsockopt(fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen); map = mmap(NULL, off.rx.desc + NUM_DESCS * sizeof(struct xdp_desc), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, sfd, XDP_PGOFF_RX_RING); prod = map + off.rx.producer; cons = map + off.rx.consumer; ring = map + off.rx.desc; Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-22xsk: proper queue id check at bindMagnus Karlsson
Validate the queue id against both Rx and Tx on the netdev. Also, make sure that the queue exists at xmit time. Reported-by: Jesper Dangaard Brouer <brouer@redhat.com> Tested-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-22xsk: remove rebind supportBjörn Töpel
Supporting rebind, i.e. after a successful bind the process can call bind again without closing the socket, makes the AF_XDP setup state machine more complex. Constrain the state space, by not supporting rebind. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-18xsk: proper '=' alignmentBjörn Töpel
Properly align xsk_proto_ops initialization. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-18xsk: fixed some cases of unnecessary parenthesesBjörn Töpel
Removed some cases of unnecessary parentheses. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-18xsk: remove newline at end of fileBjörn Töpel
Minor cleanup, remove newline at end of Makefile. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-18xsk: clean up SPDX headersBjörn Töpel
Clean up SPDX-License-Identifier and removing licensing leftovers. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-09xsk: fix 64-bit divisionBjörn Töpel
i386 builds report: net/xdp/xdp_umem.o: In function `xdp_umem_reg': xdp_umem.c:(.text+0x47e): undefined reference to `__udivdi3' This fix uses div_u64 instead of the GCC built-in. Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt") Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Reported-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-03xsk: statistics supportMagnus Karlsson
In this commit, a new getsockopt is added: XDP_STATISTICS. This is used to obtain stats from the sockets. v2: getsockopt now returns size of stats structure. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: support for TxMagnus Karlsson
Here, Tx support is added. The user fills the Tx queue with frames to be sent by the kernel, and let's the kernel know using the sendmsg syscall. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: add Tx queue setup and mmap supportMagnus Karlsson
Another setsockopt (XDP_TX_QUEUE) is added to let the process allocate a queue, where the user process can pass frames to be transmitted by the kernel. The mmapping of the queue is done using the XDP_PGOFF_TX_QUEUE offset. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: add umem completion queue support and mmapMagnus Karlsson
Here, we add another setsockopt for registered user memory (umem) called XDP_UMEM_COMPLETION_QUEUE. Using this socket option, the process can ask the kernel to allocate a queue (ring buffer) and also mmap it (XDP_UMEM_PGOFF_COMPLETION_QUEUE) into the process. The queue is used to explicitly pass ownership of umem frames from the kernel to user process. This will be used by the TX path to tell user space that a certain frame has been transmitted and user space can use it for something else, if it wishes. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03bpf: introduce new bpf AF_XDP map type BPF_MAP_TYPE_XSKMAPBjörn Töpel
The xskmap is yet another BPF map, very much inspired by dev/cpu/sockmap, and is a holder of AF_XDP sockets. A user application adds AF_XDP sockets into the map, and by using the bpf_redirect_map helper, an XDP program can redirect XDP frames to an AF_XDP socket. Note that a socket that is bound to certain ifindex/queue index will *only* accept XDP frames from that netdev/queue index. If an XDP program tries to redirect from a netdev/queue index other than what the socket is bound to, the frame will not be received on the socket. A socket can reside in multiple maps. v3: Fixed race and simplified code. v2: Removed one indirection in map lookup. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: add Rx receive functions and poll supportBjörn Töpel
Here the actual receive functions of AF_XDP are implemented, that in a later commit, will be called from the XDP layers. There's one set of functions for the XDP_DRV side and another for XDP_SKB (generic). A new XDP API, xdp_return_buff, is also introduced. Adding xdp_return_buff, which is analogous to xdp_return_frame, but acts upon an struct xdp_buff. The API will be used by AF_XDP in future commits. Support for the poll syscall is also implemented. v2: xskq_validate_id did not update cons_tail. The entries variable was calculated twice in xskq_nb_avail. Squashed xdp_return_buff commit. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: add support for bind for RxMagnus Karlsson
Here, the bind syscall is added. Binding an AF_XDP socket, means associating the socket to an umem, a netdev and a queue index. This can be done in two ways. The first way, creating a "socket from scratch". Create the umem using the XDP_UMEM_REG setsockopt and an associated fill queue with XDP_UMEM_FILL_QUEUE. Create the Rx queue using the XDP_RX_QUEUE setsockopt. Call bind passing ifindex and queue index ("channel" in ethtool speak). The second way to bind a socket, is simply skipping the umem/netdev/queue index, and passing another already setup AF_XDP socket. The new socket will then have the same umem/netdev/queue index as the parent so it will share the same umem. You must also set the flags field in the socket address to XDP_SHARED_UMEM. v2: Use PTR_ERR instead of passing error variable explicitly. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: add Rx queue setup and mmap supportBjörn Töpel
Another setsockopt (XDP_RX_QUEUE) is added to let the process allocate a queue, where the kernel can pass completed Rx frames from the kernel to user process. The mmapping of the queue is done using the XDP_PGOFF_RX_QUEUE offset. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: add umem fill queue support and mmapMagnus Karlsson
Here, we add another setsockopt for registered user memory (umem) called XDP_UMEM_FILL_QUEUE. Using this socket option, the process can ask the kernel to allocate a queue (ring buffer) and also mmap it (XDP_UMEM_PGOFF_FILL_QUEUE) into the process. The queue is used to explicitly pass ownership of umem frames from the user process to the kernel. These frames will in a later patch be filled in with Rx packet data by the kernel. v2: Fixed potential crash in xsk_mmap. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03xsk: add user memory registration support sockoptBjörn Töpel
In this commit the base structure of the AF_XDP address family is set up. Further, we introduce the abilty register a window of user memory to the kernel via the XDP_UMEM_REG setsockopt syscall. The memory window is viewed by an AF_XDP socket as a set of equally large frames. After a user memory registration all frames are "owned" by the user application, and not the kernel. v2: More robust checks on umem creation and unaccount on error. Call set_page_dirty_lock on cleanup. Simplified xdp_umem_reg. Co-authored-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-03net: initial AF_XDP skeletonBjörn Töpel
Buildable skeleton of AF_XDP without any functionality. Just what it takes to register a new address family. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>