// SPDX-License-Identifier: GPL-2.0/* * This tests the blackhole_dev that is created during the * net subsystem initialization. The test this module performs is * by injecting an skb into the stack with skb->dev as the * blackhole_dev and expects kernel to behave in a sane manner * (in other words, *not crash*)! * * Copyright (c) 2018, Mahesh Bandewar <maheshb@google.com> */ #include <kunit/test.h>#include <linux/module.h>#include <linux/skbuff.h>#include <linux/netdevice.h>#include <linux/udp.h>#include <linux/ipv6.h> #include <net/dst.h> #define SKB_SIZE  256#define HEAD_SIZE (14+40+8)	/* Ether + IPv6 + UDP */#define TAIL_SIZE 32		/* random tail-room */ #define UDP_PORT 1234 static void test_blackholedev(struct kunit *test){	struct ipv6hdr *ip6h;	struct sk_buff *skb;	struct udphdr *uh;	int data_len; 	skb = alloc_skb(SKB_SIZE, GFP_KERNEL);	KUNIT_ASSERT_NOT_NULL(test, skb); 	/* Reserve head-room for the headers */	skb_reserve(skb, HEAD_SIZE); 	/* Add data to the skb */	data_len = SKB_SIZE - (HEAD_SIZE + TAIL_SIZE);	memset(__skb_put(skb, data_len), 0xf, data_len); 	/* Add protocol data */	/* (Transport) UDP */	uh = (struct udphdr *)skb_push(skb, sizeof(struct udphdr));	skb_set_transport_header(skb, 0);	uh->source = uh->dest = htons(UDP_PORT);	udp_set_len_short(uh, data_len);	uh->check = 0;	/* (Network) IPv6 */	ip6h = (struct ipv6hdr *)skb_push(skb, sizeof(struct ipv6hdr));	skb_set_network_header(skb, 0);	ip6h->hop_limit = 32;	ip6h->payload_len = htons(data_len + sizeof(struct udphdr));	ip6h->nexthdr = IPPROTO_UDP;	ip6h->saddr = in6addr_loopback;	ip6h->daddr = in6addr_loopback;	/* Ether */	skb_push(skb, sizeof(struct ethhdr));	skb_set_mac_header(skb, 0); 	skb->protocol = htons(ETH_P_IPV6);	skb->pkt_type = PACKET_HOST;	skb->dev = blackhole_netdev; 	/* Now attempt to send the packet */	KUNIT_EXPECT_EQ(test, dev_queue_xmit(skb), NET_XMIT_SUCCESS);} static struct kunit_case blackholedev_cases[] = {	KUNIT_CASE(test_blackholedev),	{},}; static struct kunit_suite blackholedev_suite = {	.name = "blackholedev",	.test_cases = blackholedev_cases,}; kunit_test_suite(blackholedev_suite); MODULE_AUTHOR("Mahesh Bandewar <maheshb@google.com>");MODULE_DESCRIPTION("module test of the blackhole_dev");MODULE_LICENSE("GPL");