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Diffstat (limited to 'net/xfrm/xfrm_interface_bpf.c')
-rw-r--r--net/xfrm/xfrm_interface_bpf.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c
new file mode 100644
index 000000000000..1ef2162cebcf
--- /dev/null
+++ b/net/xfrm/xfrm_interface_bpf.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Unstable XFRM Helpers for TC-BPF hook
+ *
+ * These are called from SCHED_CLS BPF programs. 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_ids.h>
+
+#include <net/dst_metadata.h>
+#include <net/xfrm.h>
+
+/* bpf_xfrm_info - XFRM metadata information
+ *
+ * Members:
+ * @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
+ * @link - Underlying device ifindex:
+ * Transmit: used as the underlying device in VRF routing
+ * Receive: the device on which the packet had been received
+ */
+struct bpf_xfrm_info {
+ u32 if_id;
+ int link;
+};
+
+__diag_push();
+__diag_ignore_all("-Wmissing-prototypes",
+ "Global functions as their definitions will be in xfrm_interface BTF");
+
+/* bpf_skb_get_xfrm_info - Get XFRM metadata
+ *
+ * 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
+ */
+__used noinline
+int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to)
+{
+ struct sk_buff *skb = (struct sk_buff *)skb_ctx;
+ struct xfrm_md_info *info;
+
+ info = skb_xfrm_md_info(skb);
+ if (!info)
+ return -EINVAL;
+
+ to->if_id = info->if_id;
+ to->link = info->link;
+ return 0;
+}
+
+/* bpf_skb_get_xfrm_info - Set XFRM metadata
+ *
+ * Parameters:
+ * @skb_ctx - Pointer to ctx (__sk_buff) in TC program
+ * Cannot be NULL
+ * @from - Pointer to memory from which the metadata will be copied
+ * Cannot be NULL
+ */
+__used noinline
+int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,
+ const struct bpf_xfrm_info *from)
+{
+ struct sk_buff *skb = (struct sk_buff *)skb_ctx;
+ struct metadata_dst *md_dst;
+ struct xfrm_md_info *info;
+
+ if (unlikely(skb_metadata_dst(skb)))
+ return -EINVAL;
+
+ if (!xfrm_bpf_md_dst) {
+ struct metadata_dst __percpu *tmp;
+
+ tmp = metadata_dst_alloc_percpu(0, METADATA_XFRM, GFP_ATOMIC);
+ if (!tmp)
+ return -ENOMEM;
+ if (cmpxchg(&xfrm_bpf_md_dst, NULL, tmp))
+ metadata_dst_free_percpu(tmp);
+ }
+ md_dst = this_cpu_ptr(xfrm_bpf_md_dst);
+
+ info = &md_dst->u.xfrm_info;
+
+ info->if_id = from->if_id;
+ info->link = from->link;
+ skb_dst_force(skb);
+ info->dst_orig = skb_dst(skb);
+
+ dst_hold((struct dst_entry *)md_dst);
+ skb_dst_set(skb, (struct dst_entry *)md_dst);
+ return 0;
+}
+
+__diag_pop()
+
+BTF_SET8_START(xfrm_ifc_kfunc_set)
+BTF_ID_FLAGS(func, bpf_skb_get_xfrm_info)
+BTF_ID_FLAGS(func, bpf_skb_set_xfrm_info)
+BTF_SET8_END(xfrm_ifc_kfunc_set)
+
+static const struct btf_kfunc_id_set xfrm_interface_kfunc_set = {
+ .owner = THIS_MODULE,
+ .set = &xfrm_ifc_kfunc_set,
+};
+
+int __init register_xfrm_interface_bpf(void)
+{
+ return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
+ &xfrm_interface_kfunc_set);
+}