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// SPDX-License-Identifier: GPL-2.0-only
/* Unstable XFRM Helpers for TC-BPF hook
*
* These are called from SCHED_CLS BPF programs. Note that it is
* allowed to break compatibility for these functions since the interface they
* are exposed through to BPF programs is explicitly unstable.
*/
#include <linux/bpf.h>
#include <linux/btf_ids.h>
#include <net/dst_metadata.h>
#include <net/xfrm.h>
/* bpf_xfrm_info - XFRM metadata information
*
* Members:
* @if_id - XFRM if_id:
* Transmit: if_id to be used in policy and state lookups
* Receive: if_id of the state matched for the incoming packet
* @link - Underlying device ifindex:
* Transmit: used as the underlying device in VRF routing
* Receive: the device on which the packet had been received
*/
struct bpf_xfrm_info {
u32 if_id;
int link;
};
__bpf_kfunc_start_defs();
/* bpf_skb_get_xfrm_info - Get XFRM metadata
*
* Parameters:
* @skb_ctx - Pointer to ctx (__sk_buff) in TC program
* Cannot be NULL
* @to - Pointer to memory to which the metadata will be copied
* Cannot be NULL
*/
__bpf_kfunc int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to)
{
struct sk_buff *skb = (struct sk_buff *)skb_ctx;
struct xfrm_md_info *info;
info = skb_xfrm_md_info(skb);
if (!info)
return -EINVAL;
to->if_id = info->if_id;
to->link = info->link;
return 0;
}
/* bpf_skb_get_xfrm_info - Set XFRM metadata
*
* Parameters:
* @skb_ctx - Pointer to ctx (__sk_buff) in TC program
* Cannot be NULL
* @from - Pointer to memory from which the metadata will be copied
* Cannot be NULL
*/
__bpf_kfunc int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx, const struct bpf_xfrm_info *from)
{
struct sk_buff *skb = (struct sk_buff *)skb_ctx;
struct metadata_dst *md_dst;
struct xfrm_md_info *info;
if (unlikely(skb_metadata_dst(skb)))
return -EINVAL;
if (!xfrm_bpf_md_dst) {
struct metadata_dst __percpu *tmp;
tmp = metadata_dst_alloc_percpu(0, METADATA_XFRM, GFP_ATOMIC);
if (!tmp)
return -ENOMEM;
if (cmpxchg(&xfrm_bpf_md_dst, NULL, tmp))
metadata_dst_free_percpu(tmp);
}
md_dst = this_cpu_ptr(xfrm_bpf_md_dst);
info = &md_dst->u.xfrm_info;
info->if_id = from->if_id;
info->link = from->link;
skb_dst_force(skb);
info->dst_orig = skb_dst(skb);
dst_hold((struct dst_entry *)md_dst);
skb_dst_set(skb, (struct dst_entry *)md_dst);
return 0;
}
__bpf_kfunc_end_defs();
BTF_KFUNCS_START(xfrm_ifc_kfunc_set)
BTF_ID_FLAGS(func, bpf_skb_get_xfrm_info)
BTF_ID_FLAGS(func, bpf_skb_set_xfrm_info)
BTF_KFUNCS_END(xfrm_ifc_kfunc_set)
static const struct btf_kfunc_id_set xfrm_interface_kfunc_set = {
.owner = THIS_MODULE,
.set = &xfrm_ifc_kfunc_set,
};
int __init register_xfrm_interface_bpf(void)
{
return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
&xfrm_interface_kfunc_set);
}
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