diff options
| author | Jakub Sitnicki <jakub@cloudflare.com> | 2025-08-14 11:59:28 +0200 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2025-08-18 10:29:42 -0700 |
| commit | 6877cd392baecf816c2ba896a9d42874628004a5 (patch) | |
| tree | 13fa85d0eca4b82cf9cef66df15c1da5c5f28776 /kernel/bpf/helpers.c | |
| parent | 89d912e494f786e79f69ed9d567a8842c71dbb03 (diff) | |
bpf: Enable read/write access to skb metadata through a dynptr
Now that we can create a dynptr to skb metadata, make reads to the metadata
area possible with bpf_dynptr_read() or through a bpf_dynptr_slice(), and
make writes to the metadata area possible with bpf_dynptr_write() or
through a bpf_dynptr_slice_rdwr().
Note that for cloned skbs which share data with the original, we limit the
skb metadata dynptr to be read-only since we don't unclone on a
bpf_dynptr_write to metadata.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250814-skb-metadata-thru-dynptr-v7-2-8a39e636e0fb@cloudflare.com
Diffstat (limited to 'kernel/bpf/helpers.c')
| -rw-r--r-- | kernel/bpf/helpers.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 9552b32208c5..cdffd74ddbe6 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1781,7 +1781,8 @@ static int __bpf_dynptr_read(void *dst, u32 len, const struct bpf_dynptr_kern *s case BPF_DYNPTR_TYPE_XDP: return __bpf_xdp_load_bytes(src->data, src->offset + offset, dst, len); case BPF_DYNPTR_TYPE_SKB_META: - return -EOPNOTSUPP; /* not implemented */ + memmove(dst, bpf_skb_meta_pointer(src->data, src->offset + offset), len); + return 0; default: WARN_ONCE(true, "bpf_dynptr_read: unknown dynptr type %d\n", type); return -EFAULT; @@ -1839,7 +1840,10 @@ int __bpf_dynptr_write(const struct bpf_dynptr_kern *dst, u32 offset, void *src, return -EINVAL; return __bpf_xdp_store_bytes(dst->data, dst->offset + offset, src, len); case BPF_DYNPTR_TYPE_SKB_META: - return -EOPNOTSUPP; /* not implemented */ + if (flags) + return -EINVAL; + memmove(bpf_skb_meta_pointer(dst->data, dst->offset + offset), src, len); + return 0; default: WARN_ONCE(true, "bpf_dynptr_write: unknown dynptr type %d\n", type); return -EFAULT; @@ -2716,7 +2720,7 @@ __bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr *p, u32 offset, return buffer__opt; } case BPF_DYNPTR_TYPE_SKB_META: - return NULL; /* not implemented */ + return bpf_skb_meta_pointer(ptr->data, ptr->offset + offset); default: WARN_ONCE(true, "unknown dynptr type %d\n", type); return NULL; |