1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * This tests the blackhole_dev that is created during the
4 * net subsystem initialization. The test this module performs is
5 * by injecting an skb into the stack with skb->dev as the
6 * blackhole_dev and expects kernel to behave in a sane manner
7 * (in other words, *not crash*)!
8 *
9 * Copyright (c) 2018, Mahesh Bandewar <maheshb@google.com>
10 */
11
12 #include <kunit/test.h>
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/netdevice.h>
16 #include <linux/udp.h>
17 #include <linux/ipv6.h>
18
19 #include <net/dst.h>
20
21 #define SKB_SIZE 256
22 #define HEAD_SIZE (14+40+8) /* Ether + IPv6 + UDP */
23 #define TAIL_SIZE 32 /* random tail-room */
24
25 #define UDP_PORT 1234
26
test_blackholedev(struct kunit * test)27 static void test_blackholedev(struct kunit *test)
28 {
29 struct ipv6hdr *ip6h;
30 struct sk_buff *skb;
31 struct udphdr *uh;
32 int data_len;
33
34 skb = alloc_skb(SKB_SIZE, GFP_KERNEL);
35 KUNIT_ASSERT_NOT_NULL(test, skb);
36
37 /* Reserve head-room for the headers */
38 skb_reserve(skb, HEAD_SIZE);
39
40 /* Add data to the skb */
41 data_len = SKB_SIZE - (HEAD_SIZE + TAIL_SIZE);
42 memset(__skb_put(skb, data_len), 0xf, data_len);
43
44 /* Add protocol data */
45 /* (Transport) UDP */
46 uh = (struct udphdr *)skb_push(skb, sizeof(struct udphdr));
47 skb_set_transport_header(skb, 0);
48 uh->source = uh->dest = htons(UDP_PORT);
49 uh->len = htons(data_len);
50 uh->check = 0;
51 /* (Network) IPv6 */
52 ip6h = (struct ipv6hdr *)skb_push(skb, sizeof(struct ipv6hdr));
53 skb_set_network_header(skb, 0);
54 ip6h->hop_limit = 32;
55 ip6h->payload_len = htons(data_len + sizeof(struct udphdr));
56 ip6h->nexthdr = IPPROTO_UDP;
57 ip6h->saddr = in6addr_loopback;
58 ip6h->daddr = in6addr_loopback;
59 /* Ether */
60 skb_push(skb, sizeof(struct ethhdr));
61 skb_set_mac_header(skb, 0);
62
63 skb->protocol = htons(ETH_P_IPV6);
64 skb->pkt_type = PACKET_HOST;
65 skb->dev = blackhole_netdev;
66
67 /* Now attempt to send the packet */
68 KUNIT_EXPECT_EQ(test, dev_queue_xmit(skb), NET_XMIT_SUCCESS);
69 }
70
71 static struct kunit_case blackholedev_cases[] = {
72 KUNIT_CASE(test_blackholedev),
73 {},
74 };
75
76 static struct kunit_suite blackholedev_suite = {
77 .name = "blackholedev",
78 .test_cases = blackholedev_cases,
79 };
80
81 kunit_test_suite(blackholedev_suite);
82
83 MODULE_AUTHOR("Mahesh Bandewar <maheshb@google.com>");
84 MODULE_DESCRIPTION("module test of the blackhole_dev");
85 MODULE_LICENSE("GPL");
86