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391145ba2a
BPF kfuncs are meant to be called from BPF programs. Accordingly, most
kfuncs are not called from anywhere in the kernel, which the
-Wmissing-prototypes warning is unhappy about. We've peppered
__diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are
defined in the codebase to suppress this warning.
This patch adds two macros meant to bound one or many kfunc definitions.
All existing kfunc definitions which use these __diag calls to suppress
-Wmissing-prototypes are migrated to use the newly-introduced macros.
A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the
__bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier
version of this patch [0] and another recent mailing list thread [1].
In the future we might need to ignore different warnings or do other
kfunc-specific things. This change will make it easier to make such
modifications for all kfunc defs.
[0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/
[1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Unstable XFRM Helpers for TC-BPF hook
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*
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* These are called from SCHED_CLS BPF programs. Note that it is
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* allowed to break compatibility for these functions since the interface they
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* are exposed through to BPF programs is explicitly unstable.
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*/
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#include <linux/bpf.h>
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#include <linux/btf_ids.h>
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#include <net/dst_metadata.h>
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#include <net/xfrm.h>
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/* bpf_xfrm_info - XFRM metadata information
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*
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* Members:
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* @if_id - XFRM if_id:
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* Transmit: if_id to be used in policy and state lookups
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* Receive: if_id of the state matched for the incoming packet
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* @link - Underlying device ifindex:
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* Transmit: used as the underlying device in VRF routing
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* Receive: the device on which the packet had been received
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*/
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struct bpf_xfrm_info {
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u32 if_id;
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int link;
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};
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__bpf_kfunc_start_defs();
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/* bpf_skb_get_xfrm_info - Get XFRM metadata
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*
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* Parameters:
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* @skb_ctx - Pointer to ctx (__sk_buff) in TC program
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* Cannot be NULL
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* @to - Pointer to memory to which the metadata will be copied
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* Cannot be NULL
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*/
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__bpf_kfunc int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to)
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{
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struct sk_buff *skb = (struct sk_buff *)skb_ctx;
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struct xfrm_md_info *info;
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info = skb_xfrm_md_info(skb);
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if (!info)
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return -EINVAL;
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to->if_id = info->if_id;
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to->link = info->link;
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return 0;
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}
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/* bpf_skb_get_xfrm_info - Set XFRM metadata
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*
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* Parameters:
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* @skb_ctx - Pointer to ctx (__sk_buff) in TC program
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* Cannot be NULL
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* @from - Pointer to memory from which the metadata will be copied
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* Cannot be NULL
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*/
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__bpf_kfunc int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx, const struct bpf_xfrm_info *from)
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{
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struct sk_buff *skb = (struct sk_buff *)skb_ctx;
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struct metadata_dst *md_dst;
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struct xfrm_md_info *info;
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if (unlikely(skb_metadata_dst(skb)))
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return -EINVAL;
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if (!xfrm_bpf_md_dst) {
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struct metadata_dst __percpu *tmp;
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tmp = metadata_dst_alloc_percpu(0, METADATA_XFRM, GFP_ATOMIC);
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if (!tmp)
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return -ENOMEM;
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if (cmpxchg(&xfrm_bpf_md_dst, NULL, tmp))
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metadata_dst_free_percpu(tmp);
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}
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md_dst = this_cpu_ptr(xfrm_bpf_md_dst);
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info = &md_dst->u.xfrm_info;
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info->if_id = from->if_id;
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info->link = from->link;
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skb_dst_force(skb);
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info->dst_orig = skb_dst(skb);
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dst_hold((struct dst_entry *)md_dst);
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skb_dst_set(skb, (struct dst_entry *)md_dst);
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return 0;
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}
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__bpf_kfunc_end_defs();
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BTF_SET8_START(xfrm_ifc_kfunc_set)
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BTF_ID_FLAGS(func, bpf_skb_get_xfrm_info)
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BTF_ID_FLAGS(func, bpf_skb_set_xfrm_info)
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BTF_SET8_END(xfrm_ifc_kfunc_set)
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static const struct btf_kfunc_id_set xfrm_interface_kfunc_set = {
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.owner = THIS_MODULE,
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.set = &xfrm_ifc_kfunc_set,
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};
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int __init register_xfrm_interface_bpf(void)
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{
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return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
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&xfrm_interface_kfunc_set);
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}
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