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authorDaniel Borkmann <daniel@iogearbox.net>2017-09-09 01:40:35 +0200
committerDavid S. Miller <davem@davemloft.net>2017-09-08 21:13:09 -0700
commit9beb8bedb05c5f3a353dba62b8fa7cbbb9ec685e (patch)
treea1b746996795ad8ca61eca7380b3bd43e6d750af /net
parenta010a2f6540ecc39f8701c6f7d35e22992c03fb6 (diff)
bpf: make error reporting in bpf_warn_invalid_xdp_action more clear
Differ between illegal XDP action code and just driver unsupported one to provide better feedback when we throw a one-time warning here. Reason is that with 814abfabef3c ("xdp: add bpf_redirect helper function") not all drivers support the new XDP return code yet and thus they will fall into their 'default' case when checking for return codes after program return, which then triggers a bpf_warn_invalid_xdp_action() stating that the return code is illegal, but from XDP perspective it's not. I decided not to place something like a XDP_ACT_MAX define into uapi i) given we don't have this either for all other program types, ii) future action codes could have further encoding there, which would render such define unsuitable and we wouldn't be able to rip it out again, and iii) we rarely add new action codes. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/filter.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 0848df2cd9bf..3a50a9b021e2 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3609,7 +3609,11 @@ static bool xdp_is_valid_access(int off, int size,
void bpf_warn_invalid_xdp_action(u32 act)
{
- WARN_ONCE(1, "Illegal XDP return value %u, expect packet loss\n", act);
+ const u32 act_max = XDP_REDIRECT;
+
+ WARN_ONCE(1, "%s XDP return value %u, expect packet loss!\n",
+ act > act_max ? "Illegal" : "Driver unsupported",
+ act);
}
EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action);