From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Fri, 21 Jan 2022 11:09:54 +0100
Subject: bpf: introduce bpf_xdp_get_buff_len helper
Patch-mainline: v5.18-rc1
Git-commit: 0165cc817075cf701e4289838f1d925ff1911b3e
References: jsc#PED-373
Introduce bpf_xdp_get_buff_len helper in order to return the xdp buffer
total size (linear and paged area)
Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/aac9ac3504c84026cf66a3c71b7c5ae89bc991be.1642758637.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Acked-by: Shung-Hsi <shung-hsi.yu@suse.com>
---
include/net/xdp.h | 14 ++++++++++++++
include/uapi/linux/bpf.h | 7 +++++++
net/core/filter.c | 15 +++++++++++++++
tools/include/uapi/linux/bpf.h | 7 +++++++
4 files changed, 43 insertions(+)
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -145,6 +145,20 @@ xdp_get_shared_info_from_buff(struct xdp
return (struct skb_shared_info *)xdp_data_hard_end(xdp);
}
+static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp)
+{
+ unsigned int len = xdp->data_end - xdp->data;
+ struct skb_shared_info *sinfo;
+
+ if (likely(!xdp_buff_has_frags(xdp)))
+ goto out;
+
+ sinfo = xdp_get_shared_info_from_buff(xdp);
+ len += sinfo->xdp_frags_size;
+out:
+ return len;
+}
+
struct xdp_frame {
void *data;
u16 len;
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5054,6 +5054,12 @@ union bpf_attr {
* This helper is currently supported by cgroup programs only.
* Return
* 0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_xdp_get_buff_len(struct xdp_buff *xdp_md)
+ * Description
+ * Get the total size of a given xdp buff (linear and paged area)
+ * Return
+ * The total size of a given xdp buffer.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5244,6 +5250,7 @@ union bpf_attr {
FN(get_func_arg_cnt), \
FN(get_retval), \
FN(set_retval), \
+ FN(xdp_get_buff_len), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3803,6 +3803,19 @@ static const struct bpf_func_proto sk_sk
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_ANYTHING,
};
+
+BPF_CALL_1(bpf_xdp_get_buff_len, struct xdp_buff*, xdp)
+{
+ return xdp_get_buff_len(xdp);
+}
+
+static const struct bpf_func_proto bpf_xdp_get_buff_len_proto = {
+ .func = bpf_xdp_get_buff_len,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_PTR_TO_CTX,
+};
+
static unsigned long xdp_get_metalen(const struct xdp_buff *xdp)
{
return xdp_data_meta_unsupported(xdp) ? 0 :
@@ -7553,6 +7566,8 @@ xdp_func_proto(enum bpf_func_id func_id,
return &bpf_xdp_redirect_map_proto;
case BPF_FUNC_xdp_adjust_tail:
return &bpf_xdp_adjust_tail_proto;
+ case BPF_FUNC_xdp_get_buff_len:
+ return &bpf_xdp_get_buff_len_proto;
case BPF_FUNC_fib_lookup:
return &bpf_xdp_fib_lookup_proto;
case BPF_FUNC_check_mtu:
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5057,6 +5057,12 @@ union bpf_attr {
* This helper is currently supported by cgroup programs only.
* Return
* 0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_xdp_get_buff_len(struct xdp_buff *xdp_md)
+ * Description
+ * Get the total size of a given xdp buff (linear and paged area)
+ * Return
+ * The total size of a given xdp buffer.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5247,6 +5253,7 @@ union bpf_attr {
FN(get_func_arg_cnt), \
FN(get_retval), \
FN(set_retval), \
+ FN(xdp_get_buff_len), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper