1 // SPDX-License-Identifier: GPL-2.0
2 #include <test_progs.h>
3 #include <network_helpers.h>
4 #include <net/if.h>
5 #include "empty_skb.skel.h"
6 
7 #define SYS(cmd) ({ \
8 	if (!ASSERT_OK(system(cmd), (cmd))) \
9 		goto out; \
10 })
11 
12 void test_empty_skb(void)
13 {
14 	LIBBPF_OPTS(bpf_test_run_opts, tattr);
15 	struct empty_skb *bpf_obj = NULL;
16 	struct nstoken *tok = NULL;
17 	struct bpf_program *prog;
18 	char eth_hlen_pp[15];
19 	char eth_hlen[14];
20 	int veth_ifindex;
21 	int ipip_ifindex;
22 	int err;
23 	int i;
24 
25 	struct {
26 		const char *msg;
27 		const void *data_in;
28 		__u32 data_size_in;
29 		int *ifindex;
30 		int err;
31 		int ret;
32 		bool success_on_tc;
33 	} tests[] = {
34 		/* Empty packets are always rejected. */
35 
36 		{
37 			/* BPF_PROG_RUN ETH_HLEN size check */
38 			.msg = "veth empty ingress packet",
39 			.data_in = NULL,
40 			.data_size_in = 0,
41 			.ifindex = &veth_ifindex,
42 			.err = -EINVAL,
43 		},
44 		{
45 			/* BPF_PROG_RUN ETH_HLEN size check */
46 			.msg = "ipip empty ingress packet",
47 			.data_in = NULL,
48 			.data_size_in = 0,
49 			.ifindex = &ipip_ifindex,
50 			.err = -EINVAL,
51 		},
52 
53 		/* ETH_HLEN-sized packets:
54 		 * - can not be redirected at LWT_XMIT
55 		 * - can be redirected at TC to non-tunneling dest
56 		 */
57 
58 		{
59 			/* __bpf_redirect_common */
60 			.msg = "veth ETH_HLEN packet ingress",
61 			.data_in = eth_hlen,
62 			.data_size_in = sizeof(eth_hlen),
63 			.ifindex = &veth_ifindex,
64 			.ret = -ERANGE,
65 			.success_on_tc = true,
66 		},
67 		{
68 			/* __bpf_redirect_no_mac
69 			 *
70 			 * lwt: skb->len=0 <= skb_network_offset=0
71 			 * tc: skb->len=14 <= skb_network_offset=14
72 			 */
73 			.msg = "ipip ETH_HLEN packet ingress",
74 			.data_in = eth_hlen,
75 			.data_size_in = sizeof(eth_hlen),
76 			.ifindex = &ipip_ifindex,
77 			.ret = -ERANGE,
78 		},
79 
80 		/* ETH_HLEN+1-sized packet should be redirected. */
81 
82 		{
83 			.msg = "veth ETH_HLEN+1 packet ingress",
84 			.data_in = eth_hlen_pp,
85 			.data_size_in = sizeof(eth_hlen_pp),
86 			.ifindex = &veth_ifindex,
87 		},
88 		{
89 			.msg = "ipip ETH_HLEN+1 packet ingress",
90 			.data_in = eth_hlen_pp,
91 			.data_size_in = sizeof(eth_hlen_pp),
92 			.ifindex = &ipip_ifindex,
93 		},
94 	};
95 
96 	SYS("ip netns add empty_skb");
97 	tok = open_netns("empty_skb");
98 	SYS("ip link add veth0 type veth peer veth1");
99 	SYS("ip link set dev veth0 up");
100 	SYS("ip link set dev veth1 up");
101 	SYS("ip addr add 10.0.0.1/8 dev veth0");
102 	SYS("ip addr add 10.0.0.2/8 dev veth1");
103 	veth_ifindex = if_nametoindex("veth0");
104 
105 	SYS("ip link add ipip0 type ipip local 10.0.0.1 remote 10.0.0.2");
106 	SYS("ip link set ipip0 up");
107 	SYS("ip addr add 192.168.1.1/16 dev ipip0");
108 	ipip_ifindex = if_nametoindex("ipip0");
109 
110 	bpf_obj = empty_skb__open_and_load();
111 	if (!ASSERT_OK_PTR(bpf_obj, "open skeleton"))
112 		goto out;
113 
114 	for (i = 0; i < ARRAY_SIZE(tests); i++) {
115 		bpf_object__for_each_program(prog, bpf_obj->obj) {
116 			char buf[128];
117 			bool at_tc = !strncmp(bpf_program__section_name(prog), "tc", 2);
118 
119 			tattr.data_in = tests[i].data_in;
120 			tattr.data_size_in = tests[i].data_size_in;
121 
122 			tattr.data_size_out = 0;
123 			bpf_obj->bss->ifindex = *tests[i].ifindex;
124 			bpf_obj->bss->ret = 0;
125 			err = bpf_prog_test_run_opts(bpf_program__fd(prog), &tattr);
126 			sprintf(buf, "err: %s [%s]", tests[i].msg, bpf_program__name(prog));
127 
128 			if (at_tc && tests[i].success_on_tc)
129 				ASSERT_GE(err, 0, buf);
130 			else
131 				ASSERT_EQ(err, tests[i].err, buf);
132 			sprintf(buf, "ret: %s [%s]", tests[i].msg, bpf_program__name(prog));
133 			if (at_tc && tests[i].success_on_tc)
134 				ASSERT_GE(bpf_obj->bss->ret, 0, buf);
135 			else
136 				ASSERT_EQ(bpf_obj->bss->ret, tests[i].ret, buf);
137 		}
138 	}
139 
140 out:
141 	if (bpf_obj)
142 		empty_skb__destroy(bpf_obj);
143 	if (tok)
144 		close_netns(tok);
145 	system("ip netns del empty_skb");
146 }
147