1 files changed, 85 insertions, 0 deletions
diff --git a/lib/tests/blackhole_dev_kunit.c b/lib/tests/blackhole_dev_kunit.c
new file mode 100644
index 000000000000..06834ab35f43
--- /dev/null
+++ b/lib/tests/blackhole_dev_kunit.c
@@ -0,0 +1,85 @@
+// 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);
+	uh->len = htons(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");