Re: [PATCH bpf-next v4 12/14] selftests/bpf: test_xdp_veth: Add XDP broadcast redirection tests

On 1/30/25 11:21 PM, Bastien Curutchet (eBPF Foundation) wrote:

+#define BROADCAST_REDIRECT_SKEL_NB 2 +static void xdp_veth_broadcast_redirect(u32 attach_flags, u64 redirect_flags) +{

• struct prog_configuration prog_cfg[VETH_PAIRS_COUNT] = {

• {
  

• 	.local_name = "xdp_redirect_map_multi_prog",
  

• 	.remote_name = "xdp_count_0",
  

• 	.local_flags = attach_flags,
  

• 	.remote_flags = attach_flags,
  

• },
  

• {
  

• 	.local_name = "xdp_redirect_map_multi_prog",
  

• 	.remote_name = "xdp_count_1",
  

• 	.local_flags = attach_flags,
  

• 	.remote_flags = attach_flags,
  

• },
  

• {
  

• 	.local_name = "xdp_redirect_map_multi_prog",
  

• 	.remote_name = "xdp_count_2",
  

• 	.local_flags = attach_flags,
  

• 	.remote_flags = attach_flags,
  

• }
  

• };
• struct bpf_object *bpf_objs[BROADCAST_REDIRECT_SKEL_NB];
• struct xdp_redirect_multi_kern *xdp_redirect_multi_kern;
• struct veth_configuration net_config[VETH_PAIRS_COUNT];
• struct xdp_redirect_map *xdp_redirect_map;
• struct bpf_devmap_val devmap_val = {};
• u16 protocol = ETH_P_IP;
• int group_map;
• int flags_map;
• int cnt_map;
• u64 cnt = 0;
• int i, err;
• xdp_redirect_multi_kern = xdp_redirect_multi_kern__open_and_load();
• if (!ASSERT_OK_PTR(xdp_redirect_multi_kern, "xdp_redirect_multi_kern__open_and_load"))

• return;
  

• xdp_redirect_map = xdp_redirect_map__open_and_load();
• if (!ASSERT_OK_PTR(xdp_redirect_map, "xdp_redirect_map__open_and_load"))

• goto destroy_xdp_redirect_multi_kern;
  

• if (!ASSERT_OK(create_network(net_config), "create network"))

• goto destroy_xdp_redirect_map;
  

• group_map = bpf_map__fd(xdp_redirect_multi_kern->maps.map_all);
• if (!ASSERT_OK_FD(group_map, "open map_all"))

• goto destroy_xdp_redirect_map;
  

• flags_map = bpf_map__fd(xdp_redirect_multi_kern->maps.redirect_flags);
• if (!ASSERT_OK_FD(group_map, "open map_all"))

• goto destroy_xdp_redirect_map;
  

• err = bpf_map_update_elem(flags_map, &protocol, &redirect_flags, BPF_NOEXIST);
• if (!ASSERT_OK(err, "init IP count"))

• goto destroy_xdp_redirect_map;
  

• cnt_map = bpf_map__fd(xdp_redirect_map->maps.rxcnt);
• if (!ASSERT_OK_FD(cnt_map, "open rxcnt map"))

• goto destroy_xdp_redirect_map;
  

• bpf_objs[0] = xdp_redirect_multi_kern->obj;
• bpf_objs[1] = xdp_redirect_map->obj;
• for (i = 0; i < VETH_PAIRS_COUNT; i++) {

• int ifindex = if_nametoindex(net_config[i].local_veth);
  

• if (attach_programs_to_veth_pair(bpf_objs, BROADCAST_REDIRECT_SKEL_NB,
  

• 				 net_config, prog_cfg, i))
  

• 	goto destroy_xdp_redirect_map;
  

• SYS(destroy_xdp_redirect_map,
  

•     "ip -n %s neigh add %s lladdr 00:00:00:00:00:01 dev %s",
  

•     net_config[i].namespace, IP_NEIGH, net_config[i].remote_veth);
  

• devmap_val.ifindex = ifindex;
  

• err = bpf_map_update_elem(group_map, &ifindex, &devmap_val, 0);
  

I ran this test in a loop and failed at this line permanently (errno E2BIG -7) after enough iterations. I believe the problem is the group_map (aka "map_all" in the BPF program) has a max_entries 1024 and ifindex can go beyond 1024 after some "./test_progs" iterations. Understood that it is likely an existing assumption in the "map_all" definition but it needs to be addressed first before moving to test_progs.

• if (!ASSERT_OK(err, "bpf_map_update_elem"))
  

• 	goto destroy_xdp_redirect_map;
  

• }
• SYS_NOFAIL("ip netns exec %s ping %s -i 0.1 -c 4 -W1 > /dev/null ",

•     net_config[0].namespace, IP_NEIGH);
  

• for (i = 0; i < VETH_PAIRS_COUNT; i++) {

• err =  bpf_map_lookup_elem(cnt_map, &i, &cnt);
  

• if (!ASSERT_OK(err, "get IP cnt"))
  

• 	goto destroy_xdp_redirect_map;
  

• if (redirect_flags & BPF_F_EXCLUDE_INGRESS)
  

• 	/* veth11 shouldn't receive the ICMP requests;
  

• 	 * others should
  

• 	 */
  

• 	ASSERT_EQ(cnt, i ? 4 : 0, "compare IP cnt");
  

• else
  

• 	/* All remote veth should receive the ICMP requests */
  

• 	ASSERT_EQ(cnt, 4, "compare IP cnt");
  

• }

+destroy_xdp_redirect_map:

• xdp_redirect_map__destroy(xdp_redirect_map);

+destroy_xdp_redirect_multi_kern:

• xdp_redirect_multi_kern__destroy(xdp_redirect_multi_kern);
• cleanup_network(net_config);

+}

• void test_xdp_veth_redirect(void) { if (test__start_subtest("0"))

@@ -284,3 +411,26 @@ void test_xdp_veth_redirect(void) if (test__start_subtest("SKB_MODE")) xdp_veth_redirect(XDP_FLAGS_SKB_MODE); }

+void test_xdp_veth_broadcast_redirect(void) +{

• if (test__start_subtest("0/BROADCAST"))

• xdp_veth_broadcast_redirect(0, BPF_F_BROADCAST);
  

• if (test__start_subtest("0/(BROADCAST | EXCLUDE_INGRESS)"))

• xdp_veth_broadcast_redirect(0, BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS);
  

• if (test__start_subtest("DRV_MODE/BROADCAST"))

• xdp_veth_broadcast_redirect(XDP_FLAGS_DRV_MODE, BPF_F_BROADCAST);
  

• if (test__start_subtest("DRV_MODE/(BROADCAST | EXCLUDE_INGRESS)"))

• xdp_veth_broadcast_redirect(XDP_FLAGS_DRV_MODE,
  

• 			    BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS);
  

• if (test__start_subtest("SKB_MODE/BROADCAST"))

• xdp_veth_broadcast_redirect(XDP_FLAGS_SKB_MODE, BPF_F_BROADCAST);
  

• if (test__start_subtest("SKB_MODE/(BROADCAST | EXCLUDE_INGRESS)"))

• xdp_veth_broadcast_redirect(XDP_FLAGS_SKB_MODE,
  

• 			    BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS);
  

+} diff --git a/tools/testing/selftests/bpf/progs/xdp_redirect_map.c b/tools/testing/selftests/bpf/progs/xdp_redirect_map.c index 682dda8dabbc9abbb5d1b0b22dd5f81124142e79..14385df71d7fc40c3b0ee5c6ea0760d0e7336d71 100644 --- a/tools/testing/selftests/bpf/progs/xdp_redirect_map.c +++ b/tools/testing/selftests/bpf/progs/xdp_redirect_map.c @@ -1,7 +1,11 @@ // SPDX-License-Identifier: GPL-2.0 +#include <linux/if_ether.h> +#include <linux/ip.h>

I have compiler error complaining about __always_inline not defined. Likely ordering issue and environment specific. Regardless, I believe the ip.h is unnecessary, so better clean it up.

I am going to land the patch 1-10 and change the cover letter a little to reflect the fact that patch 11-14 will be a followup. Please post the remaining patches after fixing the bpf_map_update_elem issue. Thanks.

• #include <linux/bpf.h> #include <bpf/bpf_helpers.h>

+#include <bpf/bpf_endian.h> struct { __uint(type, BPF_MAP_TYPE_DEVMAP); @@ -28,4 +32,49 @@ int xdp_redirect_map_2(struct xdp_md *xdp) return bpf_redirect_map(&tx_port, 2, 0); } +struct {

• __uint(type, BPF_MAP_TYPE_ARRAY);
• __uint(max_entries, 3);
• __type(key, __u32);
• __type(value, __u64);

+} rxcnt SEC(".maps");

+static int xdp_count(struct xdp_md *xdp, __u32 key) +{

• void *data_end = (void *)(long)xdp->data_end;
• void *data = (void *)(long)xdp->data;
• struct ethhdr *eth = data;
• __u64 *count;
• if (data + sizeof(*eth) > data_end)

• return XDP_DROP;
  

• if (bpf_htons(eth->h_proto) == ETH_P_IP) {

• /* We only count IPv4 packets */
  

• count = bpf_map_lookup_elem(&rxcnt, &key);
  

• if (count)
  

• 	*count += 1;
  

• }
• return XDP_PASS;

+}

+SEC("xdp") +int xdp_count_0(struct xdp_md *xdp) +{

• return xdp_count(xdp, 0);

+}

+SEC("xdp") +int xdp_count_1(struct xdp_md *xdp) +{

• return xdp_count(xdp, 1);

+}

+SEC("xdp") +int xdp_count_2(struct xdp_md *xdp) +{

• return xdp_count(xdp, 2);

+}

• char _license[] SEC("license") = "GPL";