[RFC PATCH bpf-next v1 7/7] selftests/bpf: cover bpf_xdp_metadata_rx_csum in xdp_metadata
From: Vladimir Vdovin <hidden>
Date: 2026-06-30 19:18:12
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest, xdp (express data path) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds, David S. Miller, Jakub Kicinski, Jesper Dangaard Brouer, John Fastabend
Call bpf_xdp_metadata_rx_csum() in the xdp_metadata program and export the status to userspace. veth surfaces skb->ip_summed: a frame injected via AF_XDP carries no checksum context (XDP_CSUM_NONE), while one sent through the stack is CHECKSUM_PARTIAL (XDP_CSUM_VERIFIED). Assert each. Signed-off-by: Vladimir Vdovin <redacted> --- tools/testing/selftests/bpf/prog_tests/xdp_metadata.c | 10 ++++++++++ tools/testing/selftests/bpf/progs/xdp_metadata.c | 9 +++++++++ tools/testing/selftests/bpf/xdp_metadata.h | 8 ++++++++ 3 files changed, 27 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
index 5c31054ad4a4..77f55696eb78 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_metadata.c@@ -310,6 +310,16 @@ static int verify_xsk_metadata(struct xsk *xsk, bool sent_from_af_xdp) if (!ASSERT_NEQ(meta->rx_hash, 0, "rx_hash")) return -1; + /* veth surfaces the checksum verdict from skb->ip_summed. A packet + * injected via AF_XDP carries no checksum context and is CHECKSUM_NONE, + * while one sent through the stack is CHECKSUM_PARTIAL and reads back as + * verified. + */ + if (!ASSERT_EQ(meta->rx_csum_status, + sent_from_af_xdp ? XDP_META_CSUM_NONE : XDP_META_CSUM_VERIFIED, + "rx_csum_status")) + return -1; + if (!sent_from_af_xdp) { if (!ASSERT_NEQ(meta->rx_hash_type & XDP_RSS_TYPE_L4, 0, "rx_hash_type")) return -1;
diff --git a/tools/testing/selftests/bpf/progs/xdp_metadata.c b/tools/testing/selftests/bpf/progs/xdp_metadata.c
index 09bb8a038d52..0089c6c5a2e4 100644
--- a/tools/testing/selftests/bpf/progs/xdp_metadata.c
+++ b/tools/testing/selftests/bpf/progs/xdp_metadata.c@@ -33,6 +33,8 @@ extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash, extern int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx, __be16 *vlan_proto, __u16 *vlan_tci) __ksym; +extern int bpf_xdp_metadata_rx_csum(const struct xdp_md *ctx, + enum xdp_csum_status *csum_status) __ksym; SEC("xdp") int rx(struct xdp_md *ctx)
@@ -43,6 +45,7 @@ int rx(struct xdp_md *ctx) struct udphdr *udp = NULL; struct iphdr *iph = NULL; struct xdp_meta *meta; + enum xdp_csum_status csum_status; u64 timestamp = -1; int ret;
@@ -99,6 +102,12 @@ int rx(struct xdp_md *ctx) bpf_xdp_metadata_rx_vlan_tag(ctx, &meta->rx_vlan_proto, &meta->rx_vlan_tci); + ret = bpf_xdp_metadata_rx_csum(ctx, &csum_status); + if (ret < 0) + meta->rx_csum_err = ret; + else + meta->rx_csum_status = csum_status; + return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS); }
diff --git a/tools/testing/selftests/bpf/xdp_metadata.h b/tools/testing/selftests/bpf/xdp_metadata.h
index 87318ad1117a..ba1b2902b371 100644
--- a/tools/testing/selftests/bpf/xdp_metadata.h
+++ b/tools/testing/selftests/bpf/xdp_metadata.h@@ -30,6 +30,10 @@ enum xdp_meta_field { XDP_META_FIELD_VLAN_TAG = BIT(2), }; +/* Mirror of enum xdp_csum_status (include/net/xdp.h) for userspace asserts. */ +#define XDP_META_CSUM_NONE 0 +#define XDP_META_CSUM_VERIFIED 1 + struct xdp_meta { union { __u64 rx_timestamp;
@@ -48,5 +52,9 @@ struct xdp_meta { }; __s32 rx_vlan_tag_err; }; + union { + __u32 rx_csum_status; + __s32 rx_csum_err; + }; enum xdp_meta_field hint_valid; };
--
2.47.0