KFunc `bpf_skb_get_xfrm_info`

v6.2

Get XFRM metadata

Definition

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

Members

to.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

to.link: Underlying device ifindex:

Transmit: used as the underlying device in VRF routing
Receive: the device on which the packet had been received

int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to)

Usage

Docs could be improved

This part of the docs is incomplete, contributions are very welcome

Program types

The following program types can make use of this kfunc:

BPF_PROG_TYPE_SCHED_CLS

Example

// SPDX-License-Identifier: GPL-2.0
#include "vmlinux.h"
#include "bpf_tracing_net.h"
#include <bpf/bpf_helpers.h>

__u32 req_if_id;
__u32 resp_if_id;

int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,
              const struct bpf_xfrm_info *from) __ksym;
int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx,
              struct bpf_xfrm_info *to) __ksym;

SEC("tc")
int set_xfrm_info(struct __sk_buff *skb)
{
    struct bpf_xfrm_info info = { .if_id = req_if_id };

    return bpf_skb_set_xfrm_info(skb, &info) ? TC_ACT_SHOT : TC_ACT_UNSPEC;
}

SEC("tc")
int get_xfrm_info(struct __sk_buff *skb)
{
    struct bpf_xfrm_info info = {};

    if (bpf_skb_get_xfrm_info(skb, &info) < 0)
        return TC_ACT_SHOT;

    resp_if_id = info.if_id;

    return TC_ACT_UNSPEC;
}

char _license[] SEC("license") = "GPL";

KFunc bpf_skb_get_xfrm_info