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2023-07-27xsk: Honor SO_BINDTODEVICE on bindIlya Maximets
[ Upstream commit f7306acec9aae9893d15e745c8791124d42ab10a ] Initial creation of an AF_XDP socket requires CAP_NET_RAW capability. A privileged process might create the socket and pass it to a non-privileged process for later use. However, that process will be able to bind the socket to any network interface. Even though it will not be able to receive any traffic without modification of the BPF map, the situation is not ideal. Sockets already have a mechanism that can be used to restrict what interface they can be attached to. That is SO_BINDTODEVICE. To change the SO_BINDTODEVICE binding the process will need CAP_NET_RAW. Make xsk_bind() honor the SO_BINDTODEVICE in order to allow safer workflow when non-privileged process is using AF_XDP. The intended workflow is following: 1. First process creates a bare socket with socket(AF_XDP, ...). 2. First process loads the XSK program to the interface. 3. First process adds the socket fd to a BPF map. 4. First process ties socket fd to a particular interface using SO_BINDTODEVICE. 5. First process sends socket fd to a second process. 6. Second process allocates UMEM. 7. Second process binds socket to the interface with bind(...). 8. Second process sends/receives the traffic. All the steps above are possible today if the first process is privileged and the second one has sufficient RLIMIT_MEMLOCK and no capabilities. However, the second process will be able to bind the socket to any interface it wants on step 7 and send traffic from it. With the proposed change, the second process will be able to bind the socket only to a specific interface chosen by the first process at step 4. Fixes: 965a99098443 ("xsk: add support for bind for Rx") Signed-off-by: Ilya Maximets <i.maximets@ovn.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/bpf/20230703175329.3259672-1-i.maximets@ovn.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27xsk: Improve documentation for AF_XDPMagnus Karlsson
[ Upstream commit e0e4f8e938c48b7c5377661fa3e4738901e6a19b ] Added sections on all the bind flags, libbpf, all the setsockopts and all the getsockopts. Also updated the document to reflect the latest features and to correct some spelling errors. v1 -> v2: * Updated XDP program with latest BTF map format * Added one more FAQ entry * Some minor edits and corrections v2 -> v3: * Simplified XDP_SHARED_UMEM example XDP program Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/1571648224-16889-1-git-send-email-magnus.karlsson@intel.com Stable-dep-of: f7306acec9aa ("xsk: Honor SO_BINDTODEVICE on bind") Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-31doc/af_xdp: include unaligned chunk caseKevin Laatz
The addition of unaligned chunks mode, the documentation needs to be updated to indicate that the incoming addr to the fill ring will only be masked if the user application is run in the aligned chunk mode. This patch also adds a line to explicitly indicate that the incoming addr will not be masked if running the user application in the unaligned chunk mode. Signed-off-by: Kevin Laatz <kevin.laatz@intel.com> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-24xsk: sample kernel code is now in libbpfEric Leblond
Fix documentation that mention xdpsock_kern.c which has been replaced by code embedded in libbpf. Signed-off-by: Eric Leblond <eric@regit.org> Acked-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-21Documentation/networking: fix af_xdp.rst Sphinx warningsRandy Dunlap
Fix Sphinx warnings in Documentation/networking/af_xdp.rst by adding indentation: Documentation/networking/af_xdp.rst:319: WARNING: Literal block expected; none found. Documentation/networking/af_xdp.rst:326: WARNING: Literal block expected; none found. Fixes: 0f4a9b7d4ecb ("xsk: add FAQ to facilitate for first time users") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Magnus Karlsson <magnus.karlsson@intel.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-25xsk: add FAQ to facilitate for first time usersMagnus Karlsson
Added an FAQ section in Documentation/networking/af_xdp.rst to help first time users with common problems. As problems are getting identified, entries will be added to the FAQ. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-10-05bpf: typo fix in Documentation/networking/af_xdp.rstKonrad Djimeli
Fix a simple typo: Completetion -> Completion Signed-off-by: Konrad Djimeli <kdjimeli@igalia.com> Acked-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>
2018-05-03samples/bpf: sample application and documentation for AF_XDP socketsMagnus Karlsson
This is a sample application for AF_XDP sockets. The application supports three different modes of operation: rxdrop, txonly and l2fwd. To show-case a simple round-robin load-balancing between a set of sockets in an xskmap, set the RR_LB compile time define option to 1 in "xdpsock.h". v2: The entries variable was calculated twice in {umem,xq}_nb_avail. Co-authored-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>