Update xdp_adjst_head_shrnk_data to use bpf_dynptr_slice to read the
data right after the headers, instead of bpf_xdp_load_bytes.
This may avoid a copy by returning a direct pointer to the dynptr data.
Also, use bpf_dynptr_read and bpf_dynptr_write to move the headers,
instead of bpf_xdp_load_bytes and bpf_xdp_store_bytes.
Signed-off-by: Nimrod Oren <noren@xxxxxxxxxx>
Reviewed-by: Carolina Jubran <cjubran@xxxxxxxxxx>
Reviewed-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
---
.../selftests/net/lib/xdp_native.bpf.c | 35 +++++++------------
1 file changed, 12 insertions(+), 23 deletions(-)
diff --git a/tools/testing/selftests/net/lib/xdp_native.bpf.c b/tools/testing/selftests/net/lib/xdp_native.bpf.c
index ff768fbc8606..71172d32c529 100644
--- a/tools/testing/selftests/net/lib/xdp_native.bpf.c
+++ b/tools/testing/selftests/net/lib/xdp_native.bpf.c
@@ -398,10 +398,11 @@ static int xdp_adjst_tail(struct xdp_md *ctx, __u16 port)
static int xdp_adjst_head_shrnk_data(struct xdp_md *ctx, __u64 hdr_len,
__u32 offset)
{
- char tmp_buff[MAX_ADJST_OFFSET];
+ char tmp_buff[MAX_ADJST_OFFSET] = {0};
+ struct bpf_dynptr ptr;
struct udphdr *udph;
- void *offset_ptr;
__u32 udp_csum = 0;
+ void *data = NULL;
/* Update the length information in the IP and UDP headers before
* adjusting the headroom. This simplifies accessing the relevant
@@ -414,37 +415,25 @@ static int xdp_adjst_head_shrnk_data(struct xdp_md *ctx, __u64 hdr_len,
if (!udph)
return -1;
- offset = (offset & 0x1ff) >= MAX_ADJST_OFFSET ? MAX_ADJST_OFFSET :
- offset & 0xff;
- if (offset == 0)
- return -1;
-
- if (bpf_xdp_load_bytes(ctx, hdr_len, tmp_buff, offset) < 0)
+ bpf_dynptr_from_xdp(ctx, 0, &ptr);
+ data = bpf_dynptr_slice(&ptr, hdr_len, tmp_buff, sizeof(tmp_buff));
+ if (!data)
return -1;
- udp_csum = bpf_csum_diff((__be32 *)tmp_buff, offset, 0, 0, udp_csum);
+ udp_csum = bpf_csum_diff(data, offset, 0, 0, udp_csum);
udph->check = (__u16)csum_fold_helper(udp_csum);
- if (bpf_xdp_load_bytes(ctx, 0, tmp_buff, MAX_ADJST_OFFSET) < 0)
- return -1;
-
- if (bpf_xdp_adjust_head(ctx, offset) < 0)
- return -1;
-
- if (offset > MAX_ADJST_OFFSET)
- return -1;
-
- if (hdr_len > MAX_ADJST_OFFSET || hdr_len == 0)
- return -1;
-
/* Added here to handle clang complain about negative value */
hdr_len = hdr_len & 0xff;
- if (hdr_len == 0)
+ if (bpf_dynptr_read(tmp_buff, hdr_len, &ptr, 0, 0) < 0)
return -1;
- if (bpf_xdp_store_bytes(ctx, 0, tmp_buff, hdr_len) < 0)
+ if (bpf_dynptr_write(&ptr, offset, tmp_buff, hdr_len, 0) < 0)
+ return -1;
+
+ if (bpf_xdp_adjust_head(ctx, offset) < 0)
return -1;
return 0;
--
2.45.0
