KFunc bpf_xdp_xfrm_state_release
Release acquired xfrm_state object
Definition
This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects the program if any references remain in the program in all of the explored states.
Parameters
x: Pointer to referenced xfrm_state object, obtained using bpf_xdp_get_xfrm_state
void bpf_xdp_xfrm_state_release(struct xfrm_state *x)
Note
This kfunc releases the pointer passed in to it. There can be only one referenced pointer that can be passed in. All copies of the pointer being released are invalidated as a result of invoking this kfunc.
Usage
The intent for this kfunc is to support software RSS (via XDP) for the ongoing/upcoming IPsec per-CPU work. 1
Program types
The following program types can make use of this kfunc:
Example
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2016 VMware
* Copyright (c) 2016 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
volatile int xfrm_replay_window = 0;
SEC("xdp")
int xfrm_get_state_xdp(struct xdp_md *xdp)
{
struct bpf_xfrm_state_opts opts = {};
struct xfrm_state *x = NULL;
struct ip_esp_hdr *esph;
struct bpf_dynptr ptr;
u8 esph_buf[8] = {};
u8 iph_buf[20] = {};
struct iphdr *iph;
u32 off;
if (bpf_dynptr_from_xdp(xdp, 0, &ptr))
goto out;
off = sizeof(struct ethhdr);
iph = bpf_dynptr_slice(&ptr, off, iph_buf, sizeof(iph_buf));
if (!iph || iph->protocol != IPPROTO_ESP)
goto out;
off += sizeof(struct iphdr);
esph = bpf_dynptr_slice(&ptr, off, esph_buf, sizeof(esph_buf));
if (!esph)
goto out;
opts.netns_id = BPF_F_CURRENT_NETNS;
opts.daddr.a4 = iph->daddr;
opts.spi = esph->spi;
opts.proto = IPPROTO_ESP;
opts.family = AF_INET;
x = bpf_xdp_get_xfrm_state(xdp, &opts, sizeof(opts));
if (!x)
goto out;
if (!x->replay_esn)
goto out;
xfrm_replay_window = x->replay_esn->replay_window;
out:
if (x)
bpf_xdp_xfrm_state_release(x);
return XDP_PASS;
}
char _license[] SEC("license") = "GPL";