[PATCH v9 bpf-next 13/14] bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature

Lorenzo Bianconi
2021-06-14T12:52:03Z

introduce xdp_shared_info pointer in bpf_test_finish signature in order
to copy back paged data from a xdp multi-buff frame to userspace buffer

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
net/bpf/test_run.c | 47 ++++++++++++++++++++++++++++++++++++++--------
1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 5e2c8478ae18..e6b15e3d2086 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -128,7 +128,8 @@ static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat,

static int bpf_test_finish(const union bpf_attr *kattr,
union bpf_attr __user *uattr, const void *data,
- u32 size, u32 retval, u32 duration)
+ struct skb_shared_info *sinfo, u32 size,
+ u32 retval, u32 duration)
{
void __user *data_out = u64_to_user_ptr(kattr->test.data_out);
int err = -EFAULT;
@@ -143,8 +144,36 @@ static int bpf_test_finish(const union bpf_attr *kattr,
err = -ENOSPC;
}

- if (data_out && copy_to_user(data_out, data, copy_size))
- goto out;
+ if (data_out) {
+ int len = sinfo ? copy_size - sinfo->data_len : copy_size;
+
+ if (copy_to_user(data_out, data, len))
+ goto out;
+
+ if (sinfo) {
+ int i, offset = len, data_len;
+
+ for (i = 0; i < sinfo->nr_frags; i++) {
+ skb_frag_t *frag = &sinfo->frags[i];
+
+ if (offset >= copy_size) {
+ err = -ENOSPC;
+ break;
+ }
+
+ data_len = min_t(int, copy_size - offset,
+ skb_frag_size(frag));
+
+ if (copy_to_user(data_out + offset,
+ skb_frag_address(frag),
+ data_len))
+ goto out;
+
+ offset += data_len;
+ }
+ }
+ }
+
if (copy_to_user(&uattr->test.data_size_out, &size, sizeof(size)))
goto out;
if (copy_to_user(&uattr->test.retval, &retval, sizeof(retval)))
@@ -673,7 +702,8 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
/* bpf program can never convert linear skb to non-linear */
if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
size = skb_headlen(skb);
- ret = bpf_test_finish(kattr, uattr, skb->data, size, retval, duration);
+ ret = bpf_test_finish(kattr, uattr, skb->data, NULL, size, retval,
+ duration);
if (!ret)
ret = bpf_ctx_finish(kattr, uattr, ctx,
sizeof(struct __sk_buff));
@@ -755,7 +785,8 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
goto out;

size = xdp.data_end - xdp.data + sinfo->data_len;
- ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);
+ ret = bpf_test_finish(kattr, uattr, xdp.data, sinfo, size, retval,
+ duration);

out:
bpf_prog_change_xdp(prog, NULL);
@@ -841,8 +872,8 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
if (ret < 0)
goto out;

- ret = bpf_test_finish(kattr, uattr, &flow_keys, sizeof(flow_keys),
- retval, duration);
+ ret = bpf_test_finish(kattr, uattr, &flow_keys, NULL,
+ sizeof(flow_keys), retval, duration);
if (!ret)
ret = bpf_ctx_finish(kattr, uattr, user_ctx,
sizeof(struct bpf_flow_keys));
@@ -946,7 +977,7 @@ int bpf_prog_test_run_sk_lookup(struct bpf_prog *prog, const union bpf_attr *kat
user_ctx->cookie = sock_gen_cookie(ctx.selected_sk);
}

- ret = bpf_test_finish(kattr, uattr, NULL, 0, retval, duration);
+ ret = bpf_test_finish(kattr, uattr, NULL, NULL, 0, retval, duration);
if (!ret)
ret = bpf_ctx_finish(kattr, uattr, user_ctx, sizeof(*user_ctx));

--
2.31.1