tools/testing/selftests/bpf/prog_tests/xdp_do_redirect.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <test_progs.h>
   3 #include <network_helpers.h>
   4 #include <net/if.h>
   5 #include <linux/if_ether.h>
   6 #include <linux/if_packet.h>
   7 #include <linux/if_link.h>
   8 #include <linux/ipv6.h>
   9 #include <linux/in6.h>
  10 #include <linux/udp.h>
  11 #include <bpf/bpf_endian.h>
  12 #include <uapi/linux/netdev.h>
  13 #include "test_xdp_do_redirect.skel.h"
  14
  15 struct udp_packet {
  16         struct ethhdr eth;
  17         struct ipv6hdr iph;
  18         struct udphdr udp;
  19         __u8 payload[64 - sizeof(struct udphdr)
  20                      - sizeof(struct ethhdr) - sizeof(struct ipv6hdr)];
  21 } __packed;
  22
  23 static struct udp_packet pkt_udp = {
  24         .eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
  25         .eth.h_dest = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55},
  26         .eth.h_source = {0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb},
  27         .iph.version = 6,
  28         .iph.nexthdr = IPPROTO_UDP,
  29         .iph.payload_len = bpf_htons(sizeof(struct udp_packet)
  30                                      - offsetof(struct udp_packet, udp)),
  31         .iph.hop_limit = 2,
  32         .iph.saddr.s6_addr16 = {bpf_htons(0xfc00), 0, 0, 0, 0, 0, 0, bpf_htons(1)},
  33         .iph.daddr.s6_addr16 = {bpf_htons(0xfc00), 0, 0, 0, 0, 0, 0, bpf_htons(2)},
  34         .udp.source = bpf_htons(1),
  35         .udp.dest = bpf_htons(1),
  36         .udp.len = bpf_htons(sizeof(struct udp_packet)
  37                              - offsetof(struct udp_packet, udp)),
  38         .payload = {0x42}, /* receiver XDP program matches on this */
  39 };
  40
  41 static int attach_tc_prog(struct bpf_tc_hook *hook, int fd)
  42 {
  43         DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 1, .prog_fd = fd);
  44         int ret;
  45
  46         ret = bpf_tc_hook_create(hook);
  47         if (!ASSERT_OK(ret, "create tc hook"))
  48                 return ret;
  49
  50         ret = bpf_tc_attach(hook, &opts);
  51         if (!ASSERT_OK(ret, "bpf_tc_attach")) {
  52                 bpf_tc_hook_destroy(hook);
  53                 return ret;
  54         }
  55
  56         return 0;
  57 }
  58
  59 /* The maximum permissible size is: PAGE_SIZE - sizeof(struct xdp_page_head) -
  60  * SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) - XDP_PACKET_HEADROOM =
  61  * 3408 bytes for 64-byte cacheline and 3216 for 256-byte one.
  62  */
  63 #if defined(__s390x__)
  64 #define MAX_PKT_SIZE 3216
  65 #else
  66 #define MAX_PKT_SIZE 3408
  67 #endif
  68 static void test_max_pkt_size(int fd)
  69 {
  70         char data[MAX_PKT_SIZE + 1] = {};
  71         int err;
  72         DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
  73                             .data_in = &data,
  74                             .data_size_in = MAX_PKT_SIZE,
  75                             .flags = BPF_F_TEST_XDP_LIVE_FRAMES,
  76                             .repeat = 1,
  77                 );
  78         err = bpf_prog_test_run_opts(fd, &opts);
  79         ASSERT_OK(err, "prog_run_max_size");
  80
  81         opts.data_size_in += 1;
  82         err = bpf_prog_test_run_opts(fd, &opts);
  83         ASSERT_EQ(err, -EINVAL, "prog_run_too_big");
  84 }
  85
  86 #define NUM_PKTS 10000
  87 void test_xdp_do_redirect(void)
  88 {
  89         int err, xdp_prog_fd, tc_prog_fd, ifindex_src, ifindex_dst;
  90         char data[sizeof(pkt_udp) + sizeof(__u32)];
  91         struct test_xdp_do_redirect *skel = NULL;
  92         struct nstoken *nstoken = NULL;
  93         struct bpf_link *link;
  94         LIBBPF_OPTS(bpf_xdp_query_opts, query_opts);
  95         struct xdp_md ctx_in = { .data = sizeof(__u32),
  96                                  .data_end = sizeof(data) };
  97         DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
  98                             .data_in = &data,
  99                             .data_size_in = sizeof(data),
 100                             .ctx_in = &ctx_in,
 101                             .ctx_size_in = sizeof(ctx_in),
 102                             .flags = BPF_F_TEST_XDP_LIVE_FRAMES,
 103                             .repeat = NUM_PKTS,
 104                             .batch_size = 64,
 105                 );
 106         DECLARE_LIBBPF_OPTS(bpf_tc_hook, tc_hook,
 107                             .attach_point = BPF_TC_INGRESS);
 108
 109         memcpy(&data[sizeof(__u32)], &pkt_udp, sizeof(pkt_udp));
 110         *((__u32 *)data) = 0x42; /* metadata test value */
 111
 112         skel = test_xdp_do_redirect__open();
 113         if (!ASSERT_OK_PTR(skel, "skel"))
 114                 return;
 115
 116         /* The XDP program we run with bpf_prog_run() will cycle through all
 117          * three xmit (PASS/TX/REDIRECT) return codes starting from above, and
 118          * ending up with PASS, so we should end up with two packets on the dst
 119          * iface and NUM_PKTS-2 in the TC hook. We match the packets on the UDP
 120          * payload.
 121          */
 122         SYS(out, "ip netns add testns");
 123         nstoken = open_netns("testns");
 124         if (!ASSERT_OK_PTR(nstoken, "setns"))
 125                 goto out;
 126
 127         SYS(out, "ip link add veth_src type veth peer name veth_dst");
 128         SYS(out, "ip link set dev veth_src address 00:11:22:33:44:55");
 129         SYS(out, "ip link set dev veth_dst address 66:77:88:99:aa:bb");
 130         SYS(out, "ip link set dev veth_src up");
 131         SYS(out, "ip link set dev veth_dst up");
 132         SYS(out, "ip addr add dev veth_src fc00::1/64");
 133         SYS(out, "ip addr add dev veth_dst fc00::2/64");
 134         SYS(out, "ip neigh add fc00::2 dev veth_src lladdr 66:77:88:99:aa:bb");
 135
 136         /* We enable forwarding in the test namespace because that will cause
 137          * the packets that go through the kernel stack (with XDP_PASS) to be
 138          * forwarded back out the same interface (because of the packet dst
 139          * combined with the interface addresses). When this happens, the
 140          * regular forwarding path will end up going through the same
 141          * veth_xdp_xmit() call as the XDP_REDIRECT code, which can cause a
 142          * deadlock if it happens on the same CPU. There's a local_bh_disable()
 143          * in the test_run code to prevent this, but an earlier version of the
 144          * code didn't have this, so we keep the test behaviour to make sure the
 145          * bug doesn't resurface.
 146          */
 147         SYS(out, "sysctl -qw net.ipv6.conf.all.forwarding=1");
 148
 149         ifindex_src = if_nametoindex("veth_src");
 150         ifindex_dst = if_nametoindex("veth_dst");
 151         if (!ASSERT_NEQ(ifindex_src, 0, "ifindex_src") ||
 152             !ASSERT_NEQ(ifindex_dst, 0, "ifindex_dst"))
 153                 goto out;
 154
 155         /* Check xdp features supported by veth driver */
 156         err = bpf_xdp_query(ifindex_src, XDP_FLAGS_DRV_MODE, &query_opts);
 157         if (!ASSERT_OK(err, "veth_src bpf_xdp_query"))
 158                 goto out;
 159
 160         if (!ASSERT_EQ(query_opts.feature_flags,
 161                        NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
 162                        NETDEV_XDP_ACT_NDO_XMIT | NETDEV_XDP_ACT_RX_SG |
 163                        NETDEV_XDP_ACT_NDO_XMIT_SG,
 164                        "veth_src query_opts.feature_flags"))
 165                 goto out;
 166
 167         err = bpf_xdp_query(ifindex_dst, XDP_FLAGS_DRV_MODE, &query_opts);
 168         if (!ASSERT_OK(err, "veth_dst bpf_xdp_query"))
 169                 goto out;
 170
 171         if (!ASSERT_EQ(query_opts.feature_flags,
 172                        NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
 173                        NETDEV_XDP_ACT_NDO_XMIT | NETDEV_XDP_ACT_RX_SG |
 174                        NETDEV_XDP_ACT_NDO_XMIT_SG,
 175                        "veth_dst query_opts.feature_flags"))
 176                 goto out;
 177
 178         memcpy(skel->rodata->expect_dst, &pkt_udp.eth.h_dest, ETH_ALEN);
 179         skel->rodata->ifindex_out = ifindex_src; /* redirect back to the same iface */
 180         skel->rodata->ifindex_in = ifindex_src;
 181         ctx_in.ingress_ifindex = ifindex_src;
 182         tc_hook.ifindex = ifindex_src;
 183
 184         if (!ASSERT_OK(test_xdp_do_redirect__load(skel), "load"))
 185                 goto out;
 186
 187         link = bpf_program__attach_xdp(skel->progs.xdp_count_pkts, ifindex_dst);
 188         if (!ASSERT_OK_PTR(link, "prog_attach"))
 189                 goto out;
 190         skel->links.xdp_count_pkts = link;
 191
 192         tc_prog_fd = bpf_program__fd(skel->progs.tc_count_pkts);
 193         if (attach_tc_prog(&tc_hook, tc_prog_fd))
 194                 goto out;
 195
 196         xdp_prog_fd = bpf_program__fd(skel->progs.xdp_redirect);
 197         err = bpf_prog_test_run_opts(xdp_prog_fd, &opts);
 198         if (!ASSERT_OK(err, "prog_run"))
 199                 goto out_tc;
 200
 201         /* wait for the packets to be flushed */
 202         kern_sync_rcu();
 203
 204         /* There will be one packet sent through XDP_REDIRECT and one through
 205          * XDP_TX; these will show up on the XDP counting program, while the
 206          * rest will be counted at the TC ingress hook (and the counting program
 207          * resets the packet payload so they don't get counted twice even though
 208          * they are re-xmited out the veth device
 209          */
 210         ASSERT_EQ(skel->bss->pkts_seen_xdp, 2, "pkt_count_xdp");
 211         ASSERT_EQ(skel->bss->pkts_seen_zero, 2, "pkt_count_zero");
 212         ASSERT_EQ(skel->bss->pkts_seen_tc, NUM_PKTS - 2, "pkt_count_tc");
 213
 214         test_max_pkt_size(bpf_program__fd(skel->progs.xdp_count_pkts));
 215
 216 out_tc:
 217         bpf_tc_hook_destroy(&tc_hook);
 218 out:
 219         if (nstoken)
 220                 close_netns(nstoken);
 221         SYS_NOFAIL("ip netns del testns");
 222         test_xdp_do_redirect__destroy(skel);
 223 }