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Message-Id: <24653990e17e80c430632526d53916a23d92085c.1627463617.git.lorenzo@kernel.org>
Date: Wed, 28 Jul 2021 11:38:16 +0200
From: Lorenzo Bianconi <lorenzo@...nel.org>
To: bpf@...r.kernel.org, netdev@...r.kernel.org
Cc: lorenzo.bianconi@...hat.com, davem@...emloft.net, kuba@...nel.org,
ast@...nel.org, daniel@...earbox.net, shayagr@...zon.com,
john.fastabend@...il.com, dsahern@...nel.org, brouer@...hat.com,
echaudro@...hat.com, jasowang@...hat.com,
alexander.duyck@...il.com, saeed@...nel.org,
maciej.fijalkowski@...el.com, magnus.karlsson@...el.com,
tirthendu.sarkar@...el.com, toke@...hat.com
Subject: [PATCH v10 bpf-next 11/18] bpf: introduce bpf_xdp_get_buff_len helper
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@...nel.org>
---
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 2db6925e04f4..ddbf9ccc2f74 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4847,6 +4847,12 @@ union bpf_attr {
* Get address of the traced function (for tracing and kprobe programs).
* Return
* Address of the traced function.
+ *
+ * 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), \
@@ -5023,6 +5029,7 @@ union bpf_attr {
FN(timer_start), \
FN(timer_cancel), \
FN(get_func_ip), \
+ 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 e60e300b10cd..e3d34da19ef2 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3801,6 +3801,27 @@ 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;
+}
+
+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 :
@@ -7493,6 +7514,8 @@ 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 2db6925e04f4..ddbf9ccc2f74 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4847,6 +4847,12 @@ union bpf_attr {
* Get address of the traced function (for tracing and kprobe programs).
* Return
* Address of the traced function.
+ *
+ * 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), \
@@ -5023,6 +5029,7 @@ union bpf_attr {
FN(timer_start), \
FN(timer_cancel), \
FN(get_func_ip), \
+ FN(xdp_get_buff_len), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
--
2.31.1
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