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12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/printk.h>
15#include <linux/skbuff.h>
16#include <linux/netdevice.h>
17#include <linux/udp.h>
18#include <linux/ipv6.h>
19
20#include <net/dst.h>
21
22#define SKB_SIZE 256
23#define HEAD_SIZE (14+40+8)
24#define TAIL_SIZE 32
25
26#define UDP_PORT 1234
27
28static int __init test_blackholedev_init(void)
29{
30 struct ipv6hdr *ip6h;
31 struct sk_buff *skb;
32 struct ethhdr *ethh;
33 struct udphdr *uh;
34 int data_len;
35 int ret;
36
37 skb = alloc_skb(SKB_SIZE, GFP_KERNEL);
38 if (!skb)
39 return -ENOMEM;
40
41
42 skb_reserve(skb, HEAD_SIZE);
43
44
45 data_len = SKB_SIZE - (HEAD_SIZE + TAIL_SIZE);
46 memset(__skb_put(skb, data_len), 0xf, data_len);
47
48
49
50 uh = (struct udphdr *)skb_push(skb, sizeof(struct udphdr));
51 skb_set_transport_header(skb, 0);
52 uh->source = uh->dest = htons(UDP_PORT);
53 uh->len = htons(data_len);
54 uh->check = 0;
55
56 ip6h = (struct ipv6hdr *)skb_push(skb, sizeof(struct ipv6hdr));
57 skb_set_network_header(skb, 0);
58 ip6h->hop_limit = 32;
59 ip6h->payload_len = data_len + sizeof(struct udphdr);
60 ip6h->nexthdr = IPPROTO_UDP;
61 ip6h->saddr = in6addr_loopback;
62 ip6h->daddr = in6addr_loopback;
63
64 ethh = (struct ethhdr *)skb_push(skb, sizeof(struct ethhdr));
65 skb_set_mac_header(skb, 0);
66
67 skb->protocol = htons(ETH_P_IPV6);
68 skb->pkt_type = PACKET_HOST;
69 skb->dev = blackhole_netdev;
70
71
72 ret = dev_queue_xmit(skb);
73
74 switch (ret) {
75 case NET_XMIT_SUCCESS:
76 pr_warn("dev_queue_xmit() returned NET_XMIT_SUCCESS\n");
77 break;
78 case NET_XMIT_DROP:
79 pr_warn("dev_queue_xmit() returned NET_XMIT_DROP\n");
80 break;
81 case NET_XMIT_CN:
82 pr_warn("dev_queue_xmit() returned NET_XMIT_CN\n");
83 break;
84 default:
85 pr_err("dev_queue_xmit() returned UNKNOWN(%d)\n", ret);
86 }
87
88 return 0;
89}
90
91static void __exit test_blackholedev_exit(void)
92{
93 pr_warn("test_blackholedev module terminating.\n");
94}
95
96module_init(test_blackholedev_init);
97module_exit(test_blackholedev_exit);
98
99MODULE_AUTHOR("Mahesh Bandewar <maheshb@google.com>");
100MODULE_LICENSE("GPL");
101