RE: [PATCHv17 bpf-next 6/6] selftests/bpf: add xdp_redirect_multi test

Hangbin Liu wrote:

Add a bpf selftest for new helper xdp_redirect_map_multi(). In this
test we have 3 forward groups and 1 exclude group. The test will
redirect each interface's packets to all the interfaces in the forward
group, and exclude the interface in exclude map. We will also test both
DEVMAP and DEVMAP_HASH with xdp generic and drv.

For more test details, you can find it in the test script. Here is
the test result.
]# ./test_xdp_redirect_multi.sh
Pass: xdpgeneric arp ns1-2
Pass: xdpgeneric arp ns1-3
Pass: xdpgeneric arp ns1-4
Pass: xdpgeneric ping ns1-2
Pass: xdpgeneric ping ns1-3
Pass: xdpgeneric ping ns1-4
Pass: xdpgeneric ping6 ns2-1
Pass: xdpgeneric ping6 ns2-3
Pass: xdpgeneric ping6 ns2-4
Pass: xdpdrv arp ns1-2
Pass: xdpdrv arp ns1-3
Pass: xdpdrv arp ns1-4
Pass: xdpdrv ping ns1-2
Pass: xdpdrv ping ns1-3
Pass: xdpdrv ping ns1-4
Pass: xdpdrv ping6 ns2-1
Pass: xdpdrv ping6 ns2-3
Pass: xdpdrv ping6 ns2-4
Pass: xdpegress mac ns1-2
Pass: xdpegress mac ns1-3
Pass: xdpegress mac ns1-4
Pass: xdpegress ping ns1-2
Pass: xdpegress ping ns1-3
Pass: xdpegress ping ns1-4
Summary: PASS 24, FAIL 0

Acked-by: Toke Høiland-Jørgensen <redacted>
Signed-off-by: Hangbin Liu <redacted>

---
v16-v17: no update
v15: use bpf_object__find_program_by_name instead of
     bpf_object__find_program_by_title
v14: no update, only rebase the code
v13: remove setrlimit
v12: add devmap prog test on egress
v9: use NULL directly for arg2 and redefine the maps with btf format
---

[...]

+SEC("xdp_devmap/map_prog")
+int xdp_devmap_prog(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	__u32 key = ctx->egress_ifindex;
+	struct ethhdr *eth = data;
+	__u64 nh_off;
+	__be64 *mac;
+
+	nh_off = sizeof(*eth);
+	if (data + nh_off > data_end)
+		return XDP_DROP;
+
+	mac = bpf_map_lookup_elem(&mac_map, &key);
+	if (mac)
+		__builtin_memcpy(eth->h_source, mac, ETH_ALEN);
+
+	return XDP_PASS;
+}

Might be nice to also have a test for XDP_DROP. I guess the
above 'data + nh_off > data' case should not happen.

Otherwise, its not the most elegant, but testing XDP at the moment
doesn't fit into the normal test framework very well either.

Acked-by: John Fastabend <john.fastabend@gmail.com>