net/xfrm/xfrm_state_bpf.c

Source file repositories/reference/linux-study-clean/net/xfrm/xfrm_state_bpf.c

File Facts

System
Linux kernel
Corpus path
net/xfrm/xfrm_state_bpf.c
Extension
.c
Size
3546 bytes
Lines
135
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

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__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)

Annotation

Implementation Notes