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// SPDX-License-Identifier: GPL-2.0-only
/* Unstable XFRM state BPF helpers.
*
* 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.h>
#include <linux/btf_ids.h>
#include <net/xdp.h>
#include <net/xfrm.h>
/* bpf_xfrm_state_opts - Options for XFRM state lookup helpers
*
* Members:
* @error - Out parameter, set for any errors encountered
* Values:
* -EINVAL - netns_id is less than -1
* -EINVAL - opts__sz isn't BPF_XFRM_STATE_OPTS_SZ
* -ENONET - No network namespace found for netns_id
* -ENOENT - No xfrm_state found
* @netns_id - Specify the network namespace for lookup
* Values:
* BPF_F_CURRENT_NETNS (-1)
* Use namespace associated with ctx
* [0, S32_MAX]
* Network Namespace ID
* @mark - XFRM mark to match on
* @daddr - Destination address to match on
* @spi - Security parameter index to match on
* @proto - IP protocol to match on (eg. IPPROTO_ESP)
* @family - Protocol family to match on (AF_INET/AF_INET6)
*/
struct bpf_xfrm_state_opts {
s32 error;
s32 netns_id;
u32 mark;
xfrm_address_t daddr;
__be32 spi;
u8 proto;
u16 family;
};
enum {
BPF_XFRM_STATE_OPTS_SZ = sizeof(struct bpf_xfrm_state_opts),
};
__bpf_kfunc_start_defs();
/* bpf_xdp_get_xfrm_state - Get XFRM state
*
* A `struct xfrm_state *`, if found, must be released with a corresponding
* bpf_xdp_xfrm_state_release.
*
* Parameters:
* @ctx - Pointer to ctx (xdp_md) in XDP program
* Cannot be NULL
* @opts - Options for lookup (documented above)
* Cannot be NULL
* @opts__sz - Length of the bpf_xfrm_state_opts structure
* Must be BPF_XFRM_STATE_OPTS_SZ
*/
__bpf_kfunc struct xfrm_state *
bpf_xdp_get_xfrm_state(struct xdp_md *ctx, struct bpf_xfrm_state_opts *opts, u32 opts__sz)
{
struct xdp_buff *xdp = (struct xdp_buff *)ctx;
struct net *net = dev_net(xdp->rxq->dev);
struct xfrm_state *x;
if (!opts || opts__sz < sizeof(opts->error))
return NULL;
if (opts__sz != BPF_XFRM_STATE_OPTS_SZ) {
opts->error = -EINVAL;
return NULL;
}
if (unlikely(opts->netns_id < BPF_F_CURRENT_NETNS)) {
opts->error = -EINVAL;
return NULL;
}
if (opts->netns_id >= 0) {
net = get_net_ns_by_id(net, opts->netns_id);
if (unlikely(!net)) {
opts->error = -ENONET;
return NULL;
}
}
x = xfrm_state_lookup(net, opts->mark, &opts->daddr, opts->spi,
opts->proto, opts->family);
if (opts->netns_id >= 0)
put_net(net);
if (!x)
opts->error = -ENOENT;
return x;
}
/* bpf_xdp_xfrm_state_release - Release acquired xfrm_state object
*
* 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.
*/
__bpf_kfunc void bpf_xdp_xfrm_state_release(struct xfrm_state *x)
{
xfrm_state_put(x);
}
__bpf_kfunc_end_defs();
BTF_KFUNCS_START(xfrm_state_kfunc_set)
BTF_ID_FLAGS(func, bpf_xdp_get_xfrm_state, KF_RET_NULL | KF_ACQUIRE)
BTF_ID_FLAGS(func, bpf_xdp_xfrm_state_release, KF_RELEASE)
BTF_KFUNCS_END(xfrm_state_kfunc_set)
static const struct btf_kfunc_id_set xfrm_state_xdp_kfunc_set = {
.owner = THIS_MODULE,
.set = &xfrm_state_kfunc_set,
};
int __init register_xfrm_state_bpf(void)
{
return register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP,
&xfrm_state_xdp_kfunc_set);
}
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