On 11/29/22 5:20 AM, Eyal Birger wrote:
diff --git a/net/xfrm/xfrm_interface_bpf.c b/net/xfrm/xfrm_interface_bpf.c new file mode 100644 index 000000000000..757e15857dbf --- /dev/null +++ b/net/xfrm/xfrm_interface_bpf.c @@ -0,0 +1,100 @@ +// 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>
+struct bpf_xfrm_info {
No need to introduce a bpf variant of the "struct xfrm_md_info" (more on this later).
- u32 if_id;
- int link;
+};
+static struct metadata_dst __percpu *xfrm_md_dst; +__diag_push(); +__diag_ignore_all("-Wmissing-prototypes",
"Global functions as their definitions will be in xfrm_interface BTF");+__used noinline +int bpf_skb_get_xfrm_info(struct __sk_buff *skb_ctx, struct bpf_xfrm_info *to)
This kfunc is not needed. It only reads the skb->_skb_refdst. The new kfunc bpf_rdonly_cast() can be used. Take a look at the bpf_rdonly_cast() usages in the selftests/bpf/progs/type_cast.c. It was in bpf-next only but should also be in net-next now.
+{
- struct sk_buff *skb = (struct sk_buff *)skb_ctx;
- struct xfrm_md_info *info;
- memset(to, 0, sizeof(*to));
- info = skb_xfrm_md_info(skb);
- if (!info)
return -EINVAL;- to->if_id = info->if_id;
- to->link = info->link;
- return 0;
+}
+__used noinline +int bpf_skb_set_xfrm_info(struct __sk_buff *skb_ctx,
const struct bpf_xfrm_info *from)
Directly use "const struct xfrm_md_info *from" instead. This kfunc can check from->dst_orig != NULL and return -EINVAL. It will then have a consistent API with the bpf_rdonly_cast() mentioned above.
+{
- 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;- md_dst = this_cpu_ptr(xfrm_md_dst);
- info = &md_dst->u.xfrm_info;
- memset(info, 0, sizeof(*info));
Unnecessary memset here. Everything should have been initialized below. bpf_skb_set_tunnel_key() needs memset but not here.
- 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) +{
- int err;
- xfrm_md_dst = metadata_dst_alloc_percpu(0, METADATA_XFRM,
GFP_KERNEL);
May be DEFINE_PER_CPU() instead?
- if (!xfrm_md_dst)
return -ENOMEM;- err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
&xfrm_interface_kfunc_set);- if (err < 0) {
cleanup_xfrm_interface_bpf();return err;- }
- return 0;
+}
+void __exit cleanup_xfrm_interface_bpf(void) +{
- metadata_dst_free_percpu(xfrm_md_dst);
+}