bpf: Add function for XDP meta data length check

This commit prepares to use the XDP meta data length check in multiple
places by making it into a static inline function instead of a literal.

Co-developed-by: Cody Haas <chaas@riotgames.com>
Co-developed-by: Lisa Watanabe <lwatanabe@riotgames.com>
Signed-off-by: Cody Haas <chaas@riotgames.com>
Signed-off-by: Lisa Watanabe <lwatanabe@riotgames.com>
Signed-off-by: Zvi Effron <zeffron@riotgames.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210707221657.3985075-2-zeffron@riotgames.com

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 5533f0a..ad5b02d 100644 (file)
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -276,6 +276,11 @@ xdp_data_meta_unsupported(const struct xdp_buff *xdp)
        return unlikely(xdp->data_meta > xdp->data);
 }
 
+static inline bool xdp_metalen_invalid(unsigned long metalen)
+{
+       return (metalen & (sizeof(__u32) - 1)) || (metalen > 32);
+}
+
 struct xdp_attachment_info {
        struct bpf_prog *prog;
        u32 flags;

diff --git a/net/core/filter.c b/net/core/filter.c
index d70187c..f2c15b2 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -77,6 +77,7 @@
 #include <net/transp_v6.h>
 #include <linux/btf_ids.h>
 #include <net/tls.h>
+#include <net/xdp.h>
 
 static const struct bpf_func_proto *
 bpf_sk_base_func_proto(enum bpf_func_id func_id);
@@ -3880,8 +3881,7 @@ BPF_CALL_2(bpf_xdp_adjust_meta, struct xdp_buff *, xdp, int, offset)
        if (unlikely(meta < xdp_frame_end ||
                     meta > xdp->data))
                return -EINVAL;
-       if (unlikely((metalen & (sizeof(__u32) - 1)) ||
-                    (metalen > 32)))
+       if (unlikely(xdp_metalen_invalid(metalen)))
                return -EACCES;
 
        xdp->data_meta = meta;