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Diffstat (limited to 'net/xfrm/xfrm_state_bpf.c')
-rw-r--r--net/xfrm/xfrm_state_bpf.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_state_bpf.c b/net/xfrm/xfrm_state_bpf.c
new file mode 100644
index 000000000000..9e20d4a377f7
--- /dev/null
+++ b/net/xfrm/xfrm_state_bpf.c
@@ -0,0 +1,134 @@
+// 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_SET8_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_SET8_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);
+}