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path: root/tools/include/uapi/linux/bpf.h
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2023-03-01bpf: Add bpf_dynptr_slice and bpf_dynptr_slice_rdwrJoanne Koong
Two new kfuncs are added, bpf_dynptr_slice and bpf_dynptr_slice_rdwr. The user must pass in a buffer to store the contents of the data slice if a direct pointer to the data cannot be obtained. For skb and xdp type dynptrs, these two APIs are the only way to obtain a data slice. However, for other types of dynptrs, there is no difference between bpf_dynptr_slice(_rdwr) and bpf_dynptr_data. For skb type dynptrs, the data is copied into the user provided buffer if any of the data is not in the linear portion of the skb. For xdp type dynptrs, the data is copied into the user provided buffer if the data is between xdp frags. If the skb is cloned and a call to bpf_dynptr_data_rdwr is made, then the skb will be uncloned (see bpf_unclone_prologue()). Please note that any bpf_dynptr_write() automatically invalidates any prior data slices of the skb dynptr. This is because the skb may be cloned or may need to pull its paged buffer into the head. As such, any bpf_dynptr_write() will automatically have its prior data slices invalidated, even if the write is to data in the skb head of an uncloned skb. Please note as well that any other helper calls that change the underlying packet buffer (eg bpf_skb_pull_data()) invalidates any data slices of the skb dynptr as well, for the same reasons. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Link: https://lore.kernel.org/r/20230301154953.641654-10-joannelkoong@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-01bpf: Add xdp dynptrsJoanne Koong
Add xdp dynptrs, which are dynptrs whose underlying pointer points to a xdp_buff. The dynptr acts on xdp data. xdp dynptrs have two main benefits. One is that they allow operations on sizes that are not statically known at compile-time (eg variable-sized accesses). Another is that parsing the packet data through dynptrs (instead of through direct access of xdp->data and xdp->data_end) can be more ergonomic and less brittle (eg does not need manual if checking for being within bounds of data_end). For reads and writes on the dynptr, this includes reading/writing from/to and across fragments. Data slices through the bpf_dynptr_data API are not supported; instead bpf_dynptr_slice() and bpf_dynptr_slice_rdwr() should be used. For examples of how xdp dynptrs can be used, please see the attached selftests. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Link: https://lore.kernel.org/r/20230301154953.641654-9-joannelkoong@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-01bpf: Add skb dynptrsJoanne Koong
Add skb dynptrs, which are dynptrs whose underlying pointer points to a skb. The dynptr acts on skb data. skb dynptrs have two main benefits. One is that they allow operations on sizes that are not statically known at compile-time (eg variable-sized accesses). Another is that parsing the packet data through dynptrs (instead of through direct access of skb->data and skb->data_end) can be more ergonomic and less brittle (eg does not need manual if checking for being within bounds of data_end). For bpf prog types that don't support writes on skb data, the dynptr is read-only (bpf_dynptr_write() will return an error) For reads and writes through the bpf_dynptr_read() and bpf_dynptr_write() interfaces, reading and writing from/to data in the head as well as from/to non-linear paged buffers is supported. Data slices through the bpf_dynptr_data API are not supported; instead bpf_dynptr_slice() and bpf_dynptr_slice_rdwr() (added in subsequent commit) should be used. For examples of how skb dynptrs can be used, please see the attached selftests. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Link: https://lore.kernel.org/r/20230301154953.641654-8-joannelkoong@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-17bpf: Add BPF_FIB_LOOKUP_SKIP_NEIGH for bpf_fib_lookupMartin KaFai Lau
The bpf_fib_lookup() also looks up the neigh table. This was done before bpf_redirect_neigh() was added. In the use case that does not manage the neigh table and requires bpf_fib_lookup() to lookup a fib to decide if it needs to redirect or not, the bpf prog can depend only on using bpf_redirect_neigh() to lookup the neigh. It also keeps the neigh entries fresh and connected. This patch adds a bpf_fib_lookup flag, SKIP_NEIGH, to avoid the double neigh lookup when the bpf prog always call bpf_redirect_neigh() to do the neigh lookup. The params->smac output is skipped together when SKIP_NEIGH is set because bpf_redirect_neigh() will figure out the smac also. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230217205515.3583372-1-martin.lau@linux.dev
2023-02-13bpf: Add basic bpf_rb_{root,node} supportDave Marchevsky
This patch adds special BPF_RB_{ROOT,NODE} btf_field_types similar to BPF_LIST_{HEAD,NODE}, adds the necessary plumbing to detect the new types, and adds bpf_rb_root_free function for freeing bpf_rb_root in map_values. structs bpf_rb_root and bpf_rb_node are opaque types meant to obscure structs rb_root_cached rb_node, respectively. btf_struct_access will prevent BPF programs from touching these special fields automatically now that they're recognized. btf_check_and_fixup_fields now groups list_head and rb_root together as "graph root" fields and {list,rb}_node as "graph node", and does same ownership cycle checking as before. Note that this function does _not_ prevent ownership type mixups (e.g. rb_root owning list_node) - that's handled by btf_parse_graph_root. After this patch, a bpf program can have a struct bpf_rb_root in a map_value, but not add anything to nor do anything useful with it. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Link: https://lore.kernel.org/r/20230214004017.2534011-2-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-03bpf: fix typo in header for bpf_perf_prog_read_valueFlorian Lehner
Fix a simple typo in the documentation for bpf_perf_prog_read_value. Signed-off-by: Florian Lehner <dev@der-flo.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/r/20230203121439.25884-1-dev@der-flo.net Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-02-02tools/bpf: Use tab instead of white spaces to sync bpf.hTiezhu Yang
Just silence the following build warning: Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h' Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Link: https://lore.kernel.org/r/1675319486-27744-2-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-23bpf: Introduce device-bound XDP programsStanislav Fomichev
New flag BPF_F_XDP_DEV_BOUND_ONLY plus all the infra to have a way to associate a netdev with a BPF program at load time. netdevsim checks are dropped in favor of generic check in dev_xdp_attach. Cc: John Fastabend <john.fastabend@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Willem de Bruijn <willemb@google.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Anatoly Burakov <anatoly.burakov@intel.com> Cc: Alexander Lobakin <alexandr.lobakin@intel.com> Cc: Magnus Karlsson <magnus.karlsson@gmail.com> Cc: Maryam Tahhan <mtahhan@redhat.com> Cc: xdp-hints@xdp-project.net Cc: netdev@vger.kernel.org Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20230119221536.3349901-6-sdf@google.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-15bpf: Add ipip6 and ip6ip decap support for bpf_skb_adjust_room()Ziyang Xuan
Add ipip6 and ip6ip decap support for bpf_skb_adjust_room(). Main use case is for using cls_bpf on ingress hook to decapsulate IPv4 over IPv6 and IPv6 over IPv4 tunnel packets. Add two new flags BPF_F_ADJ_ROOM_DECAP_L3_IPV{4,6} to indicate the new IP header version after decapsulating the outer IP header. Suggested-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/b268ec7f0ff9431f4f43b1b40ab856ebb28cb4e1.1673574419.git.william.xuanziyang@huawei.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-12-19bpf: Add flag BPF_F_NO_TUNNEL_KEY to bpf_skb_set_tunnel_key()Christian Ehrig
This patch allows to remove TUNNEL_KEY from the tunnel flags bitmap when using bpf_skb_set_tunnel_key by providing a BPF_F_NO_TUNNEL_KEY flag. On egress, the resulting tunnel header will not contain a tunnel key if the protocol and implementation supports it. At the moment bpf_tunnel_key wants a user to specify a numeric tunnel key. This will wrap the inner packet into a tunnel header with the key bit and value set accordingly. This is problematic when using a tunnel protocol that supports optional tunnel keys and a receiving tunnel device that is not expecting packets with the key bit set. The receiver won't decapsulate and drop the packet. RFC 2890 and RFC 2784 GRE tunnels are examples where this flag is useful. It allows for generating packets, that can be decapsulated by a GRE tunnel device not operating in collect metadata mode or not expecting the key bit set. Signed-off-by: Christian Ehrig <cehrig@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20221218051734.31411-1-cehrig@cloudflare.com
2022-12-08bpf: Rework process_dynptr_funcKumar Kartikeya Dwivedi
Recently, user ringbuf support introduced a PTR_TO_DYNPTR register type for use in callback state, because in case of user ringbuf helpers, there is no dynptr on the stack that is passed into the callback. To reflect such a state, a special register type was created. However, some checks have been bypassed incorrectly during the addition of this feature. First, for arg_type with MEM_UNINIT flag which initialize a dynptr, they must be rejected for such register type. Secondly, in the future, there are plans to add dynptr helpers that operate on the dynptr itself and may change its offset and other properties. In all of these cases, PTR_TO_DYNPTR shouldn't be allowed to be passed to such helpers, however the current code simply returns 0. The rejection for helpers that release the dynptr is already handled. For fixing this, we take a step back and rework existing code in a way that will allow fitting in all classes of helpers and have a coherent model for dealing with the variety of use cases in which dynptr is used. First, for ARG_PTR_TO_DYNPTR, it can either be set alone or together with a DYNPTR_TYPE_* constant that denotes the only type it accepts. Next, helpers which initialize a dynptr use MEM_UNINIT to indicate this fact. To make the distinction clear, use MEM_RDONLY flag to indicate that the helper only operates on the memory pointed to by the dynptr, not the dynptr itself. In C parlance, it would be equivalent to taking the dynptr as a point to const argument. When either of these flags are not present, the helper is allowed to mutate both the dynptr itself and also the memory it points to. Currently, the read only status of the memory is not tracked in the dynptr, but it would be trivial to add this support inside dynptr state of the register. With these changes and renaming PTR_TO_DYNPTR to CONST_PTR_TO_DYNPTR to better reflect its usage, it can no longer be passed to helpers that initialize a dynptr, i.e. bpf_dynptr_from_mem, bpf_ringbuf_reserve_dynptr. A note to reviewers is that in code that does mark_stack_slots_dynptr, and unmark_stack_slots_dynptr, we implicitly rely on the fact that PTR_TO_STACK reg is the only case that can reach that code path, as one cannot pass CONST_PTR_TO_DYNPTR to helpers that don't set MEM_RDONLY. In both cases such helpers won't be setting that flag. The next patch will add a couple of selftest cases to make sure this doesn't break. Fixes: 205715673844 ("bpf: Add bpf_user_ringbuf_drain() helper") Acked-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221207204141.308952-4-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-23bpf: Update bpf_{g,s}etsockopt() documentationJi Rongfeng
* append missing optnames to the end * simplify bpf_getsockopt()'s doc Signed-off-by: Ji Rongfeng <SikoJobs@outlook.com> Link: https://lore.kernel.org/r/DU0P192MB15479B86200B1216EC90E162D6099@DU0P192MB1547.EURP192.PROD.OUTLOOK.COM Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-11-14bpf: Support bpf_list_head in map valuesKumar Kartikeya Dwivedi
Add the support on the map side to parse, recognize, verify, and build metadata table for a new special field of the type struct bpf_list_head. To parameterize the bpf_list_head for a certain value type and the list_node member it will accept in that value type, we use BTF declaration tags. The definition of bpf_list_head in a map value will be done as follows: struct foo { struct bpf_list_node node; int data; }; struct map_value { struct bpf_list_head head __contains(foo, node); }; Then, the bpf_list_head only allows adding to the list 'head' using the bpf_list_node 'node' for the type struct foo. The 'contains' annotation is a BTF declaration tag composed of four parts, "contains:name:node" where the name is then used to look up the type in the map BTF, with its kind hardcoded to BTF_KIND_STRUCT during the lookup. The node defines name of the member in this type that has the type struct bpf_list_node, which is actually used for linking into the linked list. For now, 'kind' part is hardcoded as struct. This allows building intrusive linked lists in BPF, using container_of to obtain pointer to entry, while being completely type safe from the perspective of the verifier. The verifier knows exactly the type of the nodes, and knows that list helpers return that type at some fixed offset where the bpf_list_node member used for this list exists. The verifier also uses this information to disallow adding types that are not accepted by a certain list. For now, no elements can be added to such lists. Support for that is coming in future patches, hence draining and freeing items is done with a TODO that will be resolved in a future patch. Note that the bpf_list_head_free function moves the list out to a local variable under the lock and releases it, doing the actual draining of the list items outside the lock. While this helps with not holding the lock for too long pessimizing other concurrent list operations, it is also necessary for deadlock prevention: unless every function called in the critical section would be notrace, a fentry/fexit program could attach and call bpf_map_update_elem again on the map, leading to the same lock being acquired if the key matches and lead to a deadlock. While this requires some special effort on part of the BPF programmer to trigger and is highly unlikely to occur in practice, it is always better if we can avoid such a condition. While notrace would prevent this, doing the draining outside the lock has advantages of its own, hence it is used to also fix the deadlock related problem. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20221114191547.1694267-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-11-11bpf: Add hwtstamp field for the sockops progMartin KaFai Lau
The bpf-tc prog has already been able to access the skb_hwtstamps(skb)->hwtstamp. This patch extends the same hwtstamp access to the sockops prog. In sockops, the skb is also available to the bpf prog during the BPF_SOCK_OPS_PARSE_HDR_OPT_CB event. There is a use case that the hwtstamp will be useful to the sockops prog to better measure the one-way-delay when the sender has put the tx timestamp in the tcp header option. Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20221107230420.4192307-2-martin.lau@linux.dev
2022-10-25bpf: Implement cgroup storage available to non-cgroup-attached bpf progsYonghong Song
Similar to sk/inode/task storage, implement similar cgroup local storage. There already exists a local storage implementation for cgroup-attached bpf programs. See map type BPF_MAP_TYPE_CGROUP_STORAGE and helper bpf_get_local_storage(). But there are use cases such that non-cgroup attached bpf progs wants to access cgroup local storage data. For example, tc egress prog has access to sk and cgroup. It is possible to use sk local storage to emulate cgroup local storage by storing data in socket. But this is a waste as it could be lots of sockets belonging to a particular cgroup. Alternatively, a separate map can be created with cgroup id as the key. But this will introduce additional overhead to manipulate the new map. A cgroup local storage, similar to existing sk/inode/task storage, should help for this use case. The life-cycle of storage is managed with the life-cycle of the cgroup struct. i.e. the storage is destroyed along with the owning cgroup with a call to bpf_cgrp_storage_free() when cgroup itself is deleted. The userspace map operations can be done by using a cgroup fd as a key passed to the lookup, update and delete operations. Typically, the following code is used to get the current cgroup: struct task_struct *task = bpf_get_current_task_btf(); ... task->cgroups->dfl_cgrp ... and in structure task_struct definition: struct task_struct { .... struct css_set __rcu *cgroups; .... } With sleepable program, accessing task->cgroups is not protected by rcu_read_lock. So the current implementation only supports non-sleepable program and supporting sleepable program will be the next step together with adding rcu_read_lock protection for rcu tagged structures. Since map name BPF_MAP_TYPE_CGROUP_STORAGE has been used for old cgroup local storage support, the new map name BPF_MAP_TYPE_CGRP_STORAGE is used for cgroup storage available to non-cgroup-attached bpf programs. The old cgroup storage supports bpf_get_local_storage() helper to get the cgroup data. The new cgroup storage helper bpf_cgrp_storage_get() can provide similar functionality. While old cgroup storage pre-allocates storage memory, the new mechanism can also pre-allocate with a user space bpf_map_update_elem() call to avoid potential run-time memory allocation failure. Therefore, the new cgroup storage can provide all functionality w.r.t. the old one. So in uapi bpf.h, the old BPF_MAP_TYPE_CGROUP_STORAGE is alias to BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED to indicate the old cgroup storage can be deprecated since the new one can provide the same functionality. Acked-by: David Vernet <void@manifault.com> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221026042850.673791-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-10-06bpf: explicitly define BPF_FUNC_xxx integer valuesAndrii Nakryiko
Historically enum bpf_func_id's BPF_FUNC_xxx enumerators relied on implicit sequential values being assigned by compiler. This is convenient, as new BPF helpers are always added at the very end, but it also has its downsides, some of them being: - with over 200 helpers now it's very hard to know what's each helper's ID, which is often important to know when working with BPF assembly (e.g., by dumping raw bpf assembly instructions with llvm-objdump -d command). it's possible to work around this by looking into vmlinux.h, dumping /sys/btf/kernel/vmlinux, looking at libbpf-provided bpf_helper_defs.h, etc. But it always feels like an unnecessary step and one should be able to quickly figure this out from UAPI header. - when backporting and cherry-picking only some BPF helpers onto older kernels it's important to be able to skip some enum values for helpers that weren't backported, but preserve absolute integer IDs to keep BPF helper IDs stable so that BPF programs stay portable across upstream and backported kernels. While neither problem is insurmountable, they come up frequently enough and are annoying enough to warrant improving the situation. And for the backporting the problem can easily go unnoticed for a while, especially if backport is done with people not very familiar with BPF subsystem overall. Anyways, it's easy to fix this by making sure that __BPF_FUNC_MAPPER macro provides explicit helper IDs. Unfortunately that would potentially break existing users that use UAPI-exposed __BPF_FUNC_MAPPER and are expected to pass macro that accepts only symbolic helper identifier (e.g., map_lookup_elem for bpf_map_lookup_elem() helper). As such, we need to introduce a new macro (___BPF_FUNC_MAPPER) which would specify both identifier and integer ID, but in such a way as to allow existing __BPF_FUNC_MAPPER be expressed in terms of new ___BPF_FUNC_MAPPER macro. And that's what this patch is doing. To avoid duplication and allow __BPF_FUNC_MAPPER stay *exactly* the same, ___BPF_FUNC_MAPPER accepts arbitrary "context" arguments, which can be used to pass any extra macros, arguments, and whatnot. In our case we use this to pass original user-provided macro that expects single argument and __BPF_FUNC_MAPPER is using it's own three-argument __BPF_FUNC_MAPPER_APPLY intermediate macro to impedance-match new and old "callback" macros. Once we resolve this, we use new ___BPF_FUNC_MAPPER to define enum bpf_func_id with explicit values. The other users of __BPF_FUNC_MAPPER in kernel (namely in kernel/bpf/disasm.c) are kept exactly the same both as demonstration that backwards compat works, but also to avoid unnecessary code churn. Note that new ___BPF_FUNC_MAPPER() doesn't forcefully insert comma between values, as that might not be appropriate in all possible cases where ___BPF_FUNC_MAPPER might be used by users. This doesn't reduce usability, as it's trivial to insert that comma inside "callback" macro. To validate all the manually specified IDs are exactly right, we used BTF to compare before and after values: $ bpftool btf dump file ~/linux-build/default/vmlinux | rg bpf_func_id -A 211 > after.txt $ git stash # stach UAPI changes $ make -j90 ... re-building kernel without UAPI changes ... $ bpftool btf dump file ~/linux-build/default/vmlinux | rg bpf_func_id -A 211 > before.txt $ diff -u before.txt after.txt --- before.txt 2022-10-05 10:48:18.119195916 -0700 +++ after.txt 2022-10-05 10:46:49.446615025 -0700 @@ -1,4 +1,4 @@ -[14576] ENUM 'bpf_func_id' encoding=UNSIGNED size=4 vlen=211 +[9560] ENUM 'bpf_func_id' encoding=UNSIGNED size=4 vlen=211 'BPF_FUNC_unspec' val=0 'BPF_FUNC_map_lookup_elem' val=1 'BPF_FUNC_map_update_elem' val=2 As can be seen from diff above, the only thing that changed was resulting BTF type ID of ENUM bpf_func_id, not any of the enumerators, their names or integer values. The only other place that needed fixing was scripts/bpf_doc.py used to generate man pages and bpf_helper_defs.h header for libbpf and selftests. That script is tightly-coupled to exact shape of ___BPF_FUNC_MAPPER macro definition, so had to be trivially adapted. Cc: Quentin Monnet <quentin@isovalent.com> Reported-by: Andrea Terzolo <andrea.terzolo@polito.it> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/r/20221006042452.2089843-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-10-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Merge in the left-over fixes before the net-next pull-request. Conflicts: drivers/net/ethernet/mediatek/mtk_ppe.c ae3ed15da588 ("net: ethernet: mtk_eth_soc: fix state in __mtk_foe_entry_clear") 9d8cb4c096ab ("net: ethernet: mtk_eth_soc: add foe_entry_size to mtk_eth_soc") https://lore.kernel.org/all/6cb6893b-4921-a068-4c30-1109795110bb@tessares.net/ kernel/bpf/helpers.c 8addbfc7b308 ("bpf: Gate dynptr API behind CAP_BPF") 5679ff2f138f ("bpf: Move bpf_loop and bpf_for_each_map_elem under CAP_BPF") 8a67f2de9b1d ("bpf: expose bpf_strtol and bpf_strtoul to all program types") https://lore.kernel.org/all/20221003201957.13149-1-daniel@iogearbox.net/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-28bpf: Handle bpf_link_info for the parameterized task BPF iterators.Kui-Feng Lee
Add new fields to bpf_link_info that users can query it through bpf_obj_get_info_by_fd(). Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/bpf/20220926184957.208194-3-kuifeng@fb.com
2022-09-28bpf: Parameterize task iterators.Kui-Feng Lee
Allow creating an iterator that loops through resources of one thread/process. People could only create iterators to loop through all resources of files, vma, and tasks in the system, even though they were interested in only the resources of a specific task or process. Passing the additional parameters, people can now create an iterator to go through all resources or only the resources of a task. Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/bpf/20220926184957.208194-2-kuifeng@fb.com
2022-09-26bpf: Return value in kprobe get_func_ip only for entry addressJiri Olsa
Changing return value of kprobe's version of bpf_get_func_ip to return zero if the attach address is not on the function's entry point. For kprobes attached in the middle of the function we can't easily get to the function address especially now with the CONFIG_X86_KERNEL_IBT support. If user cares about current IP for kprobes attached within the function body, they can get it with PT_REGS_IP(ctx). Suggested-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Martynas Pumputis <m@lambda.lt> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20220926153340.1621984-6-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-21bpf: Add bpf_user_ringbuf_drain() helperDavid Vernet
In a prior change, we added a new BPF_MAP_TYPE_USER_RINGBUF map type which will allow user-space applications to publish messages to a ring buffer that is consumed by a BPF program in kernel-space. In order for this map-type to be useful, it will require a BPF helper function that BPF programs can invoke to drain samples from the ring buffer, and invoke callbacks on those samples. This change adds that capability via a new BPF helper function: bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx, u64 flags) BPF programs may invoke this function to run callback_fn() on a series of samples in the ring buffer. callback_fn() has the following signature: long callback_fn(struct bpf_dynptr *dynptr, void *context); Samples are provided to the callback in the form of struct bpf_dynptr *'s, which the program can read using BPF helper functions for querying struct bpf_dynptr's. In order to support bpf_ringbuf_drain(), a new PTR_TO_DYNPTR register type is added to the verifier to reflect a dynptr that was allocated by a helper function and passed to a BPF program. Unlike PTR_TO_STACK dynptrs which are allocated on the stack by a BPF program, PTR_TO_DYNPTR dynptrs need not use reference tracking, as the BPF helper is trusted to properly free the dynptr before returning. The verifier currently only supports PTR_TO_DYNPTR registers that are also DYNPTR_TYPE_LOCAL. Note that while the corresponding user-space libbpf logic will be added in a subsequent patch, this patch does contain an implementation of the .map_poll() callback for BPF_MAP_TYPE_USER_RINGBUF maps. This .map_poll() callback guarantees that an epoll-waiting user-space producer will receive at least one event notification whenever at least one sample is drained in an invocation of bpf_user_ringbuf_drain(), provided that the function is not invoked with the BPF_RB_NO_WAKEUP flag. If the BPF_RB_FORCE_WAKEUP flag is provided, a wakeup notification is sent even if no sample was drained. Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220920000100.477320-3-void@manifault.com
2022-09-21bpf: Define new BPF_MAP_TYPE_USER_RINGBUF map typeDavid Vernet
We want to support a ringbuf map type where samples are published from user-space, to be consumed by BPF programs. BPF currently supports a kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF map type. We'll need to define a new map type for user-space -> kernel, as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply to a user-space producer ring buffer, and we'll want to add one or more helper functions that would not apply for a kernel-producer ring buffer. This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type definition. The map type is useless in its current form, as there is no way to access or use it for anything until we one or more BPF helpers. A follow-on patch will therefore add a new helper function that allows BPF programs to run callbacks on samples that are published to the ring buffer. Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
2022-09-21bpf, cgroup: Reject prog_attach_flags array when effective queryPu Lehui
Attach flags is only valid for attached progs of this layer cgroup, but not for effective progs. For querying with EFFECTIVE flags, exporting attach flags does not make sense. So when effective query, we reject prog_attach_flags array and don't need to populate it. Also we limit attach_flags to output 0 during effective query. Fixes: b79c9fc9551b ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP") Signed-off-by: Pu Lehui <pulehui@huawei.com> Link: https://lore.kernel.org/r/20220921104604.2340580-2-pulehui@huaweicloud.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-09-06bpf: Update descriptions for helpers bpf_get_func_arg[_cnt]()Yonghong Song
Now instead of the number of arguments, the number of registers holding argument values are stored in trampoline. Update the description of bpf_get_func_arg[_cnt]() helpers. Previous programs without struct arguments should continue to work as usual. Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220831152657.2078805-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-02bpf: Support getting tunnel flagsShmulik Ladkani
Existing 'bpf_skb_get_tunnel_key' extracts various tunnel parameters (id, ttl, tos, local and remote) but does not expose ip_tunnel_info's tun_flags to the BPF program. It makes sense to expose tun_flags to the BPF program. Assume for example multiple GRE tunnels maintained on a single GRE interface in collect_md mode. The program expects origins to initiate over GRE, however different origins use different GRE characteristics (e.g. some prefer to use GRE checksum, some do not; some pass a GRE key, some do not, etc..). A BPF program getting tun_flags can therefore remember the relevant flags (e.g. TUNNEL_CSUM, TUNNEL_SEQ...) for each initiating remote. In the reply path, the program can use 'bpf_skb_set_tunnel_key' in order to correctly reply to the remote, using similar characteristics, based on the stored tunnel flags. Introduce BPF_F_TUNINFO_FLAGS flag for bpf_skb_get_tunnel_key. If specified, 'bpf_tunnel_key->tunnel_flags' is set with the tun_flags. Decided to use the existing unused 'tunnel_ext' as the storage for the 'tunnel_flags' in order to avoid changing bpf_tunnel_key's layout. Also, the following has been considered during the design: 1. Convert the "interesting" internal TUNNEL_xxx flags back to BPF_F_yyy and place into the new 'tunnel_flags' field. This has 2 drawbacks: - The BPF_F_yyy flags are from *set_tunnel_key* enumeration space, e.g. BPF_F_ZERO_CSUM_TX. It is awkward that it is "returned" into tunnel_flags from a *get_tunnel_key* call. - Not all "interesting" TUNNEL_xxx flags can be mapped to existing BPF_F_yyy flags, and it doesn't make sense to create new BPF_F_yyy flags just for purposes of the returned tunnel_flags. 2. Place key.tun_flags into 'tunnel_flags' but mask them, keeping only "interesting" flags. That's ok, but the drawback is that what's "interesting" for my usecase might be limiting for other usecases. Therefore I decided to expose what's in key.tun_flags *as is*, which seems most flexible. The BPF user can just choose to ignore bits he's not interested in. The TUNNEL_xxx are also UAPI, so no harm exposing them back in the get_tunnel_key call. Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220831144010.174110-1-shmulik.ladkani@gmail.com
2022-08-26bpf: Fix a few typos in BPF helpers documentationQuentin Monnet
Address a few typos in the documentation for the BPF helper functions. They were reported by Jakub [0], who ran spell checkers on the generated man page [1]. [0] https://lore.kernel.org/linux-man/d22dcd47-023c-8f52-d369-7b5308e6c842@gmail.com/T/#mb02e7d4b7fb61d98fa914c77b581184e9a9537af [1] https://lore.kernel.org/linux-man/eb6a1e41-c48e-ac45-5154-ac57a2c76108@gmail.com/T/#m4a8d1b003616928013ffcd1450437309ab652f9f v3: Do not copy unrelated (and breaking) elements to tools/ header v2: Turn a ',' into a ';' Reported-by: Jakub Wilk <jwilk@jwilk.net> Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220825220806.107143-1-quentin@isovalent.com
2022-08-25bpf: Add CGROUP prefix to cgroup_iter_orderHao Luo
bpf_cgroup_iter_order is globally visible but the entries do not have CGROUP prefix. As requested by Andrii, put a CGROUP in the names in bpf_cgroup_iter_order. This patch fixes two previous commits: one introduced the API and the other uses the API in bpf selftest (that is, the selftest cgroup_hierarchical_stats). I tested this patch via the following command: test_progs -t cgroup,iter,btf_dump Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter") Fixes: 88886309d2e8 ("selftests/bpf: add a selftest for cgroup hierarchical stats collection") Suggested-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/r/20220825223936.1865810-1-haoluo@google.com Signed-off-by: Martin KaFai Lau <kafai@fb.com>
2022-08-25bpf: Introduce cgroup iterHao Luo
Cgroup_iter is a type of bpf_iter. It walks over cgroups in four modes: - walking a cgroup's descendants in pre-order. - walking a cgroup's descendants in post-order. - walking a cgroup's ancestors. - process only the given cgroup. When attaching cgroup_iter, one can set a cgroup to the iter_link created from attaching. This cgroup is passed as a file descriptor or cgroup id and serves as the starting point of the walk. If no cgroup is specified, the starting point will be the root cgroup v2. For walking descendants, one can specify the order: either pre-order or post-order. For walking ancestors, the walk starts at the specified cgroup and ends at the root. One can also terminate the walk early by returning 1 from the iter program. Note that because walking cgroup hierarchy holds cgroup_mutex, the iter program is called with cgroup_mutex held. Currently only one session is supported, which means, depending on the volume of data bpf program intends to send to user space, the number of cgroups that can be walked is limited. For example, given the current buffer size is 8 * PAGE_SIZE, if the program sends 64B data for each cgroup, assuming PAGE_SIZE is 4kb, the total number of cgroups that can be walked is 512. This is a limitation of cgroup_iter. If the output data is larger than the kernel buffer size, after all data in the kernel buffer is consumed by user space, the subsequent read() syscall will signal EOPNOTSUPP. In order to work around, the user may have to update their program to reduce the volume of data sent to output. For example, skip some uninteresting cgroups. In future, we may extend bpf_iter flags to allow customizing buffer size. Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/r/20220824233117.1312810-2-haoluo@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-23bpf: update bpf_{g,s}et_retval documentationStanislav Fomichev
* replace 'syscall' with 'upper layers', still mention that it's being exported via syscall errno * describe what happens in set_retval(-EPERM) + return 1 * describe what happens with bind's 'return 3' Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20220823222555.523590-5-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-23bpf, flow_dissector: Introduce BPF_FLOW_DISSECTOR_CONTINUE retcode for bpf progsShmulik Ladkani
Currently, attaching BPF_PROG_TYPE_FLOW_DISSECTOR programs completely replaces the flow-dissector logic with custom dissection logic. This forces implementors to write programs that handle dissection for any flows expected in the namespace. It makes sense for flow-dissector BPF programs to just augment the dissector with custom logic (e.g. dissecting certain flows or custom protocols), while enjoying the broad capabilities of the standard dissector for any other traffic. Introduce BPF_FLOW_DISSECTOR_CONTINUE retcode. Flow-dissector BPF programs may return this to indicate no dissection was made, and fallback to the standard dissector is requested. Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Stanislav Fomichev <sdf@google.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20220821113519.116765-3-shmulik.ladkani@gmail.com
2022-08-15bpf: Clear up confusion in bpf_skb_adjust_room()'s documentationQuentin Monnet
Adding or removing room space _below_ layers 2 or 3, as the description mentions, is ambiguous. This was written with a mental image of the packet with layer 2 at the top, layer 3 under it, and so on. But it has led users to believe that it was on lower layers (before the beginning of the L2 and L3 headers respectively). Let's make it more explicit, and specify between which layers the room space is adjusted. Reported-by: Rumen Telbizov <rumen.telbizov@menlosecurity.com> Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220812153727.224500-3-quentin@isovalent.com
2022-08-09bpf: Add BPF-helper for accessing CLOCK_TAIJesper Dangaard Brouer
Commit 3dc6ffae2da2 ("timekeeping: Introduce fast accessor to clock tai") introduced a fast and NMI-safe accessor for CLOCK_TAI. Especially in time sensitive networks (TSN), where all nodes are synchronized by Precision Time Protocol (PTP), it's helpful to have the possibility to generate timestamps based on CLOCK_TAI instead of CLOCK_MONOTONIC. With a BPF helper for TAI in place, it becomes very convenient to correlate activity across different machines in the network. Use cases for such a BPF helper include functionalities such as Tx launch time (e.g. ETF and TAPRIO Qdiscs) and timestamping. Note: CLOCK_TAI is nothing new per se, only the NMI-safe variant of it is. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> [Kurt: Wrote changelog and renamed helper] Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de> Link: https://lore.kernel.org/r/20220809060803.5773-2-kurt@linutronix.de Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-08bpf: Improve docstring for BPF_F_USER_BUILD_ID flagDave Marchevsky
Most tools which use bpf_get_stack or bpf_get_stackid symbolicate the stack - meaning the stack of addresses in the target process' address space is transformed into meaningful symbol names. The BPF_F_USER_BUILD_ID flag eases this process by finding the build_id of the file-backed vma which the address falls in and translating the address to an offset within the backing file. To be more specific, the offset is a "file offset" from the beginning of the backing file. The symbols in ET_DYN ELF objects have a st_value which is also described as an "offset" - but an offset in the process address space, relative to the base address of the object. It's necessary to translate between the "file offset" and "virtual address offset" during symbolication before they can be directly compared. Failure to do so can lead to confusing bugs, so this patch clarifies language in the documentation in an attempt to keep this from happening. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220808164723.3107500-1-davemarchevsky@fb.com
2022-07-22Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski
Daniel Borkmann says: ==================== bpf-next 2022-07-22 We've added 73 non-merge commits during the last 12 day(s) which contain a total of 88 files changed, 3458 insertions(+), 860 deletions(-). The main changes are: 1) Implement BPF trampoline for arm64 JIT, from Xu Kuohai. 2) Add ksyscall/kretsyscall section support to libbpf to simplify tracing kernel syscalls through kprobe mechanism, from Andrii Nakryiko. 3) Allow for livepatch (KLP) and BPF trampolines to attach to the same kernel function, from Song Liu & Jiri Olsa. 4) Add new kfunc infrastructure for netfilter's CT e.g. to insert and change entries, from Kumar Kartikeya Dwivedi & Lorenzo Bianconi. 5) Add a ksym BPF iterator to allow for more flexible and efficient interactions with kernel symbols, from Alan Maguire. 6) Bug fixes in libbpf e.g. for uprobe binary path resolution, from Dan Carpenter. 7) Fix BPF subprog function names in stack traces, from Alexei Starovoitov. 8) libbpf support for writing custom perf event readers, from Jon Doron. 9) Switch to use SPDX tag for BPF helper man page, from Alejandro Colomar. 10) Fix xsk send-only sockets when in busy poll mode, from Maciej Fijalkowski. 11) Reparent BPF maps and their charging on memcg offlining, from Roman Gushchin. 12) Multiple follow-up fixes around BPF lsm cgroup infra, from Stanislav Fomichev. 13) Use bootstrap version of bpftool where possible to speed up builds, from Pu Lehui. 14) Cleanup BPF verifier's check_func_arg() handling, from Joanne Koong. 15) Make non-prealloced BPF map allocations low priority to play better with memcg limits, from Yafang Shao. 16) Fix BPF test runner to reject zero-length data for skbs, from Zhengchao Shao. 17) Various smaller cleanups and improvements all over the place. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (73 commits) bpf: Simplify bpf_prog_pack_[size|mask] bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch) bpf, x64: Allow to use caller address from stack ftrace: Allow IPMODIFY and DIRECT ops on the same function ftrace: Add modify_ftrace_direct_multi_nolock bpf/selftests: Fix couldn't retrieve pinned program in xdp veth test bpf: Fix build error in case of !CONFIG_DEBUG_INFO_BTF selftests/bpf: Fix test_verifier failed test in unprivileged mode selftests/bpf: Add negative tests for new nf_conntrack kfuncs selftests/bpf: Add tests for new nf_conntrack kfuncs selftests/bpf: Add verifier tests for trusted kfunc args net: netfilter: Add kfuncs to set and change CT status net: netfilter: Add kfuncs to set and change CT timeout net: netfilter: Add kfuncs to allocate and insert CT net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup bpf: Add documentation for kfuncs bpf: Add support for forcing kfunc args to be trusted bpf: Switch to new kfunc flags infrastructure tools/resolve_btfids: Add support for 8-byte BTF sets bpf: Introduce 8-byte BTF set ... ==================== Link: https://lore.kernel.org/r/20220722221218.29943-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-19bpf: fix bpf_skb_pull_data documentationJoanne Koong
Fix documentation for bpf_skb_pull_data() helper for when len == 0. Fixes: fa15601ab31e ("bpf: add documentation for eBPF helpers (33-41)") Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Acked-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/r/20220715193800.3940070-1-joannelkoong@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
include/net/sock.h 310731e2f161 ("net: Fix data-races around sysctl_mem.") e70f3c701276 ("Revert "net: set SK_MEM_QUANTUM to 4096"") https://lore.kernel.org/all/20220711120211.7c8b7cba@canb.auug.org.au/ net/ipv4/fib_semantics.c 747c14307214 ("ip: fix dflt addr selection for connected nexthop") d62607c3fe45 ("net: rename reference+tracking helpers") net/tls/tls.h include/net/tls.h 3d8c51b25a23 ("net/tls: Check for errors in tls_device_init") 587903142308 ("tls: create an internal header") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-07-08bpf: Add flags arg to bpf_dynptr_read and bpf_dynptr_write APIsJoanne Koong
Commit 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write") added the bpf_dynptr_write() and bpf_dynptr_read() APIs. However, it will be needed for some dynptr types to pass in flags as well (e.g. when writing to a skb, the user may like to invalidate the hash or recompute the checksum). This patch adds a "u64 flags" arg to the bpf_dynptr_read() and bpf_dynptr_write() APIs before their UAPI signature freezes where we then cannot change them anymore with a 5.19.x released kernel. Fixes: 13bbbfbea759 ("bpf: Add bpf_dynptr_read and bpf_dynptr_write") Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20220706232547.4016651-1-joannelkoong@gmail.com
2022-07-05bpf: Introduce TYPE_MATCH related constants/macrosDaniel Müller
In order to provide type match support we require a new type of relocation which, in turn, requires toolchain support. Recent LLVM/Clang versions support a new value for the last argument to the __builtin_preserve_type_info builtin, for example. With this change we introduce the necessary constants into relevant header files, mirroring what the compiler may support. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220628160127.607834-2-deso@posteo.net
2022-06-29tools/bpf: Sync btf_ids.h to toolsStanislav Fomichev
Has been slowly getting out of sync, let's update it. resolve_btfids usage has been updated to match the header changes. Also bring new parts of tools/include/uapi/linux/bpf.h. Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20220628174314.1216643-8-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-29bpf: per-cgroup lsm flavorStanislav Fomichev
Allow attaching to lsm hooks in the cgroup context. Attaching to per-cgroup LSM works exactly like attaching to other per-cgroup hooks. New BPF_LSM_CGROUP is added to trigger new mode; the actual lsm hook we attach to is signaled via existing attach_btf_id. For the hooks that have 'struct socket' or 'struct sock' as its first argument, we use the cgroup associated with that socket. For the rest, we use 'current' cgroup (this is all on default hierarchy == v2 only). Note that for some hooks that work on 'struct sock' we still take the cgroup from 'current' because some of them work on the socket that hasn't been properly initialized yet. Behind the scenes, we allocate a shim program that is attached to the trampoline and runs cgroup effective BPF programs array. This shim has some rudimentary ref counting and can be shared between several programs attaching to the same lsm hook from different cgroups. Note that this patch bloats cgroup size because we add 211 cgroup_bpf_attach_type(s) for simplicity sake. This will be addressed in the subsequent patch. Also note that we only add non-sleepable flavor for now. To enable sleepable use-cases, bpf_prog_run_array_cg has to grab trace rcu, shim programs have to be freed via trace rcu, cgroup_bpf.effective should be also trace-rcu-managed + maybe some other changes that I'm not aware of. Reviewed-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20220628174314.1216643-4-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-16bpf: Add helpers to issue and check SYN cookies in XDPMaxim Mikityanskiy
The new helpers bpf_tcp_raw_{gen,check}_syncookie_ipv{4,6} allow an XDP program to generate SYN cookies in response to TCP SYN packets and to check those cookies upon receiving the first ACK packet (the final packet of the TCP handshake). Unlike bpf_tcp_{gen,check}_syncookie these new helpers don't need a listening socket on the local machine, which allows to use them together with synproxy to accelerate SYN cookie generation. Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Link: https://lore.kernel.org/r/20220615134847.3753567-4-maximmi@nvidia.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-06-16bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookieMaxim Mikityanskiy
bpf_tcp_gen_syncookie expects the full length of the TCP header (with all options), and bpf_tcp_check_syncookie accepts lengths bigger than sizeof(struct tcphdr). Fix the documentation that says these lengths should be exactly sizeof(struct tcphdr). While at it, fix a typo in the name of struct ipv6hdr. Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Link: https://lore.kernel.org/r/20220615134847.3753567-2-maximmi@nvidia.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-23bpf: Add dynptr data slicesJoanne Koong
This patch adds a new helper function void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len); which returns a pointer to the underlying data of a dynptr. *len* must be a statically known value. The bpf program may access the returned data slice as a normal buffer (eg can do direct reads and writes), since the verifier associates the length with the returned pointer, and enforces that no out of bounds accesses occur. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220523210712.3641569-6-joannelkoong@gmail.com
2022-05-23bpf: Add bpf_dynptr_read and bpf_dynptr_writeJoanne Koong
This patch adds two helper functions, bpf_dynptr_read and bpf_dynptr_write: long bpf_dynptr_read(void *dst, u32 len, struct bpf_dynptr *src, u32 offset); long bpf_dynptr_write(struct bpf_dynptr *dst, u32 offset, void *src, u32 len); The dynptr passed into these functions must be valid dynptrs that have been initialized. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220523210712.3641569-5-joannelkoong@gmail.com
2022-05-23bpf: Dynptr support for ring buffersJoanne Koong
Currently, our only way of writing dynamically-sized data into a ring buffer is through bpf_ringbuf_output but this incurs an extra memcpy cost. bpf_ringbuf_reserve + bpf_ringbuf_commit avoids this extra memcpy, but it can only safely support reservation sizes that are statically known since the verifier cannot guarantee that the bpf program won’t access memory outside the reserved space. The bpf_dynptr abstraction allows for dynamically-sized ring buffer reservations without the extra memcpy. There are 3 new APIs: long bpf_ringbuf_reserve_dynptr(void *ringbuf, u32 size, u64 flags, struct bpf_dynptr *ptr); void bpf_ringbuf_submit_dynptr(struct bpf_dynptr *ptr, u64 flags); void bpf_ringbuf_discard_dynptr(struct bpf_dynptr *ptr, u64 flags); These closely follow the functionalities of the original ringbuf APIs. For example, all ringbuffer dynptrs that have been reserved must be either submitted or discarded before the program exits. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20220523210712.3641569-4-joannelkoong@gmail.com
2022-05-23bpf: Add bpf_dynptr_from_mem for local dynptrsJoanne Koong
This patch adds a new api bpf_dynptr_from_mem: long bpf_dynptr_from_mem(void *data, u32 size, u64 flags, struct bpf_dynptr *ptr); which initializes a dynptr to point to a bpf program's local memory. For now only local memory that is of reg type PTR_TO_MAP_VALUE is supported. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220523210712.3641569-3-joannelkoong@gmail.com
2022-05-23bpf: Add verifier support for dynptrsJoanne Koong
This patch adds the bulk of the verifier work for supporting dynamic pointers (dynptrs) in bpf. A bpf_dynptr is opaque to the bpf program. It is a 16-byte structure defined internally as: struct bpf_dynptr_kern { void *data; u32 size; u32 offset; } __aligned(8); The upper 8 bits of *size* is reserved (it contains extra metadata about read-only status and dynptr type). Consequently, a dynptr only supports memory less than 16 MB. There are different types of dynptrs (eg malloc, ringbuf, ...). In this patchset, the most basic one, dynptrs to a bpf program's local memory, is added. For now only local memory that is of reg type PTR_TO_MAP_VALUE is supported. In the verifier, dynptr state information will be tracked in stack slots. When the program passes in an uninitialized dynptr (ARG_PTR_TO_DYNPTR | MEM_UNINIT), the stack slots corresponding to the frame pointer where the dynptr resides at are marked STACK_DYNPTR. For helper functions that take in initialized dynptrs (eg bpf_dynptr_read + bpf_dynptr_write which are added later in this patchset), the verifier enforces that the dynptr has been initialized properly by checking that their corresponding stack slots have been marked as STACK_DYNPTR. The 6th patch in this patchset adds test cases that the verifier should successfully reject, such as for example attempting to use a dynptr after doing a direct write into it inside the bpf program. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20220523210712.3641569-2-joannelkoong@gmail.com
2022-05-20bpf: Add bpf_skc_to_mptcp_sock_protoGeliang Tang
This patch implements a new struct bpf_func_proto, named bpf_skc_to_mptcp_sock_proto. Define a new bpf_id BTF_SOCK_TYPE_MPTCP, and a new helper bpf_skc_to_mptcp_sock(), which invokes another new helper bpf_mptcp_sock_from_subflow() in net/mptcp/bpf.c to get struct mptcp_sock from a given subflow socket. v2: Emit BTF type, add func_id checks in verifier.c and bpf_trace.c, remove build check for CONFIG_BPF_JIT v5: Drop EXPORT_SYMBOL (Martin) Co-developed-by: Nicolas Rybowski <nicolas.rybowski@tessares.net> Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Geliang Tang <geliang.tang@suse.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220519233016.105670-2-mathew.j.martineau@linux.intel.com
2022-05-11bpf: add bpf_map_lookup_percpu_elem for percpu mapFeng Zhou
Add new ebpf helpers bpf_map_lookup_percpu_elem. The implementation method is relatively simple, refer to the implementation method of map_lookup_elem of percpu map, increase the parameters of cpu, and obtain it according to the specified cpu. Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com> Link: https://lore.kernel.org/r/20220511093854.411-2-zhoufeng.zf@bytedance.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-10bpf, x86: Attach a cookie to fentry/fexit/fmod_ret/lsm.Kui-Feng Lee
Pass a cookie along with BPF_LINK_CREATE requests. Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie. The cookie of a bpf_tracing_link is available by calling bpf_get_attach_cookie when running the BPF program of the attached link. The value of a cookie will be set at bpf_tramp_run_ctx by the trampoline of the link. Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com