113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
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// 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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__diag_push();
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__diag_ignore_all("-Wmissing-prototypes",
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"Global functions as their definitions will be in xfrm_interface BTF");
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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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__diag_pop()
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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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