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/ipv6.h>
8 #include <linux/in6.h>
9 #include <linux/udp.h>
10 #include <bpf/bpf_endian.h>
11 #include "test_xdp_do_redirect.skel.h"
12
13 #define SYS(fmt, ...) \
14 ({ \
15 char cmd[1024]; \
16 snprintf(cmd, sizeof(cmd), fmt, ##__VA_ARGS__); \
17 if (!ASSERT_OK(system(cmd), cmd)) \
18 goto out; \
19 })
20
21 struct udp_packet {
22 struct ethhdr eth;
23 struct ipv6hdr iph;
24 struct udphdr udp;
25 __u8 payload[64 - sizeof(struct udphdr)
26 - sizeof(struct ethhdr) - sizeof(struct ipv6hdr)];
27 } __packed;
28
29 static struct udp_packet pkt_udp = {
30 .eth.h_proto = __bpf_constant_htons(ETH_P_IPV6),
31 .eth.h_dest = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55},
32 .eth.h_source = {0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb},
33 .iph.version = 6,
34 .iph.nexthdr = IPPROTO_UDP,
35 .iph.payload_len = bpf_htons(sizeof(struct udp_packet)
36 - offsetof(struct udp_packet, udp)),
37 .iph.hop_limit = 2,
38 .iph.saddr.s6_addr16 = {bpf_htons(0xfc00), 0, 0, 0, 0, 0, 0, bpf_htons(1)},
39 .iph.daddr.s6_addr16 = {bpf_htons(0xfc00), 0, 0, 0, 0, 0, 0, bpf_htons(2)},
40 .udp.source = bpf_htons(1),
41 .udp.dest = bpf_htons(1),
42 .udp.len = bpf_htons(sizeof(struct udp_packet)
43 - offsetof(struct udp_packet, udp)),
44 .payload = {0x42}, /* receiver XDP program matches on this */
45 };
46
attach_tc_prog(struct bpf_tc_hook * hook,int fd)47 static int attach_tc_prog(struct bpf_tc_hook *hook, int fd)
48 {
49 DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 1, .prog_fd = fd);
50 int ret;
51
52 ret = bpf_tc_hook_create(hook);
53 if (!ASSERT_OK(ret, "create tc hook"))
54 return ret;
55
56 ret = bpf_tc_attach(hook, &opts);
57 if (!ASSERT_OK(ret, "bpf_tc_attach")) {
58 bpf_tc_hook_destroy(hook);
59 return ret;
60 }
61
62 return 0;
63 }
64
65 /* The maximum permissible size is: PAGE_SIZE - sizeof(struct xdp_page_head) -
66 * sizeof(struct skb_shared_info) - XDP_PACKET_HEADROOM = 3368 bytes
67 */
68 #define MAX_PKT_SIZE 3368
test_max_pkt_size(int fd)69 static void test_max_pkt_size(int fd)
70 {
71 char data[MAX_PKT_SIZE + 1] = {};
72 int err;
73 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
74 .data_in = &data,
75 .data_size_in = MAX_PKT_SIZE,
76 .flags = BPF_F_TEST_XDP_LIVE_FRAMES,
77 .repeat = 1,
78 );
79 err = bpf_prog_test_run_opts(fd, &opts);
80 ASSERT_OK(err, "prog_run_max_size");
81
82 opts.data_size_in += 1;
83 err = bpf_prog_test_run_opts(fd, &opts);
84 ASSERT_EQ(err, -EINVAL, "prog_run_too_big");
85 }
86
87 #define NUM_PKTS 10000
serial_test_xdp_do_redirect(void)88 void serial_test_xdp_do_redirect(void)
89 {
90 int err, xdp_prog_fd, tc_prog_fd, ifindex_src, ifindex_dst;
91 char data[sizeof(pkt_udp) + sizeof(__u32)];
92 struct test_xdp_do_redirect *skel = NULL;
93 struct nstoken *nstoken = NULL;
94 struct bpf_link *link;
95
96 struct xdp_md ctx_in = { .data = sizeof(__u32),
97 .data_end = sizeof(data) };
98 DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
99 .data_in = &data,
100 .data_size_in = sizeof(data),
101 .ctx_in = &ctx_in,
102 .ctx_size_in = sizeof(ctx_in),
103 .flags = BPF_F_TEST_XDP_LIVE_FRAMES,
104 .repeat = NUM_PKTS,
105 .batch_size = 64,
106 );
107 DECLARE_LIBBPF_OPTS(bpf_tc_hook, tc_hook,
108 .attach_point = BPF_TC_INGRESS);
109
110 memcpy(&data[sizeof(__u32)], &pkt_udp, sizeof(pkt_udp));
111 *((__u32 *)data) = 0x42; /* metadata test value */
112
113 skel = test_xdp_do_redirect__open();
114 if (!ASSERT_OK_PTR(skel, "skel"))
115 return;
116
117 /* The XDP program we run with bpf_prog_run() will cycle through all
118 * three xmit (PASS/TX/REDIRECT) return codes starting from above, and
119 * ending up with PASS, so we should end up with two packets on the dst
120 * iface and NUM_PKTS-2 in the TC hook. We match the packets on the UDP
121 * payload.
122 */
123 SYS("ip netns add testns");
124 nstoken = open_netns("testns");
125 if (!ASSERT_OK_PTR(nstoken, "setns"))
126 goto out;
127
128 SYS("ip link add veth_src type veth peer name veth_dst");
129 SYS("ip link set dev veth_src address 00:11:22:33:44:55");
130 SYS("ip link set dev veth_dst address 66:77:88:99:aa:bb");
131 SYS("ip link set dev veth_src up");
132 SYS("ip link set dev veth_dst up");
133 SYS("ip addr add dev veth_src fc00::1/64");
134 SYS("ip addr add dev veth_dst fc00::2/64");
135 SYS("ip neigh add fc00::2 dev veth_src lladdr 66:77:88:99:aa:bb");
136
137 /* We enable forwarding in the test namespace because that will cause
138 * the packets that go through the kernel stack (with XDP_PASS) to be
139 * forwarded back out the same interface (because of the packet dst
140 * combined with the interface addresses). When this happens, the
141 * regular forwarding path will end up going through the same
142 * veth_xdp_xmit() call as the XDP_REDIRECT code, which can cause a
143 * deadlock if it happens on the same CPU. There's a local_bh_disable()
144 * in the test_run code to prevent this, but an earlier version of the
145 * code didn't have this, so we keep the test behaviour to make sure the
146 * bug doesn't resurface.
147 */
148 SYS("sysctl -qw net.ipv6.conf.all.forwarding=1");
149
150 ifindex_src = if_nametoindex("veth_src");
151 ifindex_dst = if_nametoindex("veth_dst");
152 if (!ASSERT_NEQ(ifindex_src, 0, "ifindex_src") ||
153 !ASSERT_NEQ(ifindex_dst, 0, "ifindex_dst"))
154 goto out;
155
156 memcpy(skel->rodata->expect_dst, &pkt_udp.eth.h_dest, ETH_ALEN);
157 skel->rodata->ifindex_out = ifindex_src; /* redirect back to the same iface */
158 skel->rodata->ifindex_in = ifindex_src;
159 ctx_in.ingress_ifindex = ifindex_src;
160 tc_hook.ifindex = ifindex_src;
161
162 if (!ASSERT_OK(test_xdp_do_redirect__load(skel), "load"))
163 goto out;
164
165 link = bpf_program__attach_xdp(skel->progs.xdp_count_pkts, ifindex_dst);
166 if (!ASSERT_OK_PTR(link, "prog_attach"))
167 goto out;
168 skel->links.xdp_count_pkts = link;
169
170 tc_prog_fd = bpf_program__fd(skel->progs.tc_count_pkts);
171 if (attach_tc_prog(&tc_hook, tc_prog_fd))
172 goto out;
173
174 xdp_prog_fd = bpf_program__fd(skel->progs.xdp_redirect);
175 err = bpf_prog_test_run_opts(xdp_prog_fd, &opts);
176 if (!ASSERT_OK(err, "prog_run"))
177 goto out_tc;
178
179 /* wait for the packets to be flushed */
180 kern_sync_rcu();
181
182 /* There will be one packet sent through XDP_REDIRECT and one through
183 * XDP_TX; these will show up on the XDP counting program, while the
184 * rest will be counted at the TC ingress hook (and the counting program
185 * resets the packet payload so they don't get counted twice even though
186 * they are re-xmited out the veth device
187 */
188 ASSERT_EQ(skel->bss->pkts_seen_xdp, 2, "pkt_count_xdp");
189 ASSERT_EQ(skel->bss->pkts_seen_zero, 2, "pkt_count_zero");
190 ASSERT_EQ(skel->bss->pkts_seen_tc, NUM_PKTS - 2, "pkt_count_tc");
191
192 test_max_pkt_size(bpf_program__fd(skel->progs.xdp_count_pkts));
193
194 out_tc:
195 bpf_tc_hook_destroy(&tc_hook);
196 out:
197 if (nstoken)
198 close_netns(nstoken);
199 system("ip netns del testns");
200 test_xdp_do_redirect__destroy(skel);
201 }
202