Introduce bpf_xdp_get_buff_len helper in order to return the xdp buffer
total size (linear and paged area)
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
---
include/uapi/linux/bpf.h | 7 +++++++
net/core/filter.c | 23 +++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 7 +++++++
3 files changed, 37 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c4f7892edb2b..9e2c3b12ea49 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4871,6 +4871,12 @@ union bpf_attr {
* Return
* Value specified by user at BPF link creation/attachment time
* or 0, if it was not specified.
+ *
+ * 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), \
@@ -5048,6 +5054,7 @@ union bpf_attr {
FN(timer_cancel), \
FN(get_func_ip), \
FN(get_attach_cookie), \
+ FN(xdp_get_buff_len), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
diff --git a/net/core/filter.c b/net/core/filter.c
index e6a589705813..53eaae2a5463 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3784,6 +3784,27 @@ static const struct bpf_func_proto sk_skb_change_head_proto = {
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_ANYTHING,
};
+
+BPF_CALL_1(bpf_xdp_get_buff_len, struct xdp_buff*, xdp)
+{
+ u64 len = xdp->data_end - xdp->data;
+
+ if (unlikely(xdp_buff_is_mb(xdp))) {
+ struct skb_shared_info *sinfo;
+
+ sinfo = xdp_get_shared_info_from_buff(xdp);
+ len += sinfo->xdp_frags_size;
+ }
+ return len;
+}
+
+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 :
@@ -7513,6 +7534,8 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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:
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c4f7892edb2b..9e2c3b12ea49 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4871,6 +4871,12 @@ union bpf_attr {
* Return
* Value specified by user at BPF link creation/attachment time
* or 0, if it was not specified.
+ *
+ * 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), \
@@ -5048,6 +5054,7 @@ union bpf_attr {
FN(timer_cancel), \
FN(get_func_ip), \
FN(get_attach_cookie), \
+ FN(xdp_get_buff_len), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
--
2.31.1
