@@ -123,6 +123,6 @@ $(OUTPUT)/reuseport_bpf_numa: LDLIBS += -lnuma
 $(OUTPUT)/tcp_mmap: LDLIBS += -lpthread -lcrypto
 $(OUTPUT)/tcp_inq: LDLIBS += -lpthread
 $(OUTPUT)/bind_bhash: LDLIBS += -lpthread
-$(OUTPUT)/io_uring_zerocopy_tx: CFLAGS += -I../../../include/
+$(OUTPUT)/io_uring_zerocopy_tx $(OUTPUT)/tun: CFLAGS += -I../../../include/
 
 include bpf.mk

@@ -2,21 +2,37 @@
 
 #define _GNU_SOURCE
 
+#include <endian.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <linux/if.h>
+#include <net/if.h>
+#include <netinet/ip.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/compiler.h>
+#include <linux/icmp.h>
+#include <linux/if_arp.h>
 #include <linux/if_tun.h>
+#include <linux/ipv6.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
-#include <sys/ioctl.h>
-#include <sys/socket.h>
+#include <linux/sockios.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/virtio_net.h>
 
 #include "../kselftest_harness.h"
 
+#define TUN_HWADDR_SOURCE { 0x02, 0x00, 0x00, 0x00, 0x00, 0x00 }
+#define TUN_HWADDR_DEST { 0x02, 0x00, 0x00, 0x00, 0x00, 0x01 }
+#define TUN_IPADDR_SOURCE htonl((172 << 24) | (17 << 16) | 0)
+#define TUN_IPADDR_DEST htonl((172 << 24) | (17 << 16) | 1)
+
 static int tun_attach(int fd, char *dev)
 {
 	struct ifreq ifr;

@@ -39,7 +55,7 @@ static int tun_detach(int fd, char *dev)
 	return ioctl(fd, TUNSETQUEUE, (void *) &ifr);
 }
 
-static int tun_alloc(char *dev)
+static int tun_alloc(char *dev, short flags)
 {
 	struct ifreq ifr;
 	int fd, err;

@@ -52,7 +68,8 @@ static int tun_alloc(char *dev)
 
 	memset(&ifr, 0, sizeof(ifr));
 	strcpy(ifr.ifr_name, dev);
-	ifr.ifr_flags = IFF_TAP | IFF_NAPI | IFF_MULTI_QUEUE;
+	ifr.ifr_flags = flags | IFF_TAP | IFF_NAPI | IFF_NO_PI |
+			IFF_MULTI_QUEUE;
 
 	err = ioctl(fd, TUNSETIFF, (void *) &ifr);
 	if (err < 0) {

@@ -64,6 +81,40 @@ static int tun_alloc(char *dev)
 	return fd;
 }
 
+static bool tun_add_to_bridge(int local_fd, const char *name)
+{
+	struct ifreq ifreq = {
+		.ifr_name = "xbridge",
+		.ifr_ifindex = if_nametoindex(name)
+	};
+
+	if (!ifreq.ifr_ifindex) {
+		perror("if_nametoindex");
+		return false;
+	}
+
+	if (ioctl(local_fd, SIOCBRADDIF, &ifreq)) {
+		perror("SIOCBRADDIF");
+		return false;
+	}
+
+	return true;
+}
+
+static bool tun_set_flags(int local_fd, const char *name, short flags)
+{
+	struct ifreq ifreq = { .ifr_flags = flags };
+
+	strcpy(ifreq.ifr_name, name);
+
+	if (ioctl(local_fd, SIOCSIFFLAGS, &ifreq)) {
+		perror("SIOCSIFFLAGS");
+		return false;
+	}
+
+	return true;
+}
+
 static int tun_delete(char *dev)
 {
 	struct {

@@ -102,6 +153,156 @@ static int tun_delete(char *dev)
 	return ret;
 }
 
+static uint32_t tun_sum(const void *buf, size_t len)
+{
+	const uint16_t *sbuf = buf;
+	uint32_t sum = 0;
+
+	while (len > 1) {
+		sum += *sbuf++;
+		len -= 2;
+	}
+
+	if (len)
+		sum += *(uint8_t *)sbuf;
+
+	return sum;
+}
+
+static uint16_t tun_build_ip_check(uint32_t sum)
+{
+	return ~((sum & 0xffff) + (sum >> 16));
+}
+
+static uint32_t tun_build_ip_pseudo_sum(const void *iphdr)
+{
+	uint16_t tot_len = ntohs(((struct iphdr *)iphdr)->tot_len);
+
+	return tun_sum((char *)iphdr + offsetof(struct iphdr, saddr), 8) +
+	       htons(((struct iphdr *)iphdr)->protocol) +
+	       htons(tot_len - sizeof(struct iphdr));
+}
+
+static uint32_t tun_build_ipv6_pseudo_sum(const void *ipv6hdr)
+{
+	return tun_sum((char *)ipv6hdr + offsetof(struct ipv6hdr, saddr), 32) +
+	       ((struct ipv6hdr *)ipv6hdr)->payload_len +
+	       htons(((struct ipv6hdr *)ipv6hdr)->nexthdr);
+}
+
+static void tun_build_ethhdr(struct ethhdr *ethhdr, uint16_t proto)
+{
+	*ethhdr = (struct ethhdr) {
+		.h_dest = TUN_HWADDR_DEST,
+		.h_source = TUN_HWADDR_SOURCE,
+		.h_proto = htons(proto)
+	};
+}
+
+static void tun_build_iphdr(void *dest, uint16_t len, uint8_t protocol)
+{
+	struct iphdr iphdr = {
+		.ihl = sizeof(iphdr) / 4,
+		.version = 4,
+		.tot_len = htons(sizeof(iphdr) + len),
+		.ttl = 255,
+		.protocol = protocol,
+		.saddr = TUN_IPADDR_SOURCE,
+		.daddr = TUN_IPADDR_DEST
+	};
+
+	iphdr.check = tun_build_ip_check(tun_sum(&iphdr, sizeof(iphdr)));
+	memcpy(dest, &iphdr, sizeof(iphdr));
+}
+
+static void tun_build_ipv6hdr(void *dest, uint16_t len, uint8_t protocol)
+{
+	struct ipv6hdr ipv6hdr = {
+		.version = 6,
+		.payload_len = htons(len),
+		.nexthdr = protocol,
+		.saddr = {
+			.s6_addr32 = {
+				htonl(0xffff0000), 0, 0, TUN_IPADDR_SOURCE
+			}
+		},
+		.daddr = {
+			.s6_addr32 = {
+				htonl(0xffff0000), 0, 0, TUN_IPADDR_DEST
+			}
+		},
+	};
+
+	memcpy(dest, &ipv6hdr, sizeof(ipv6hdr));
+}
+
+static void tun_build_tcphdr(void *dest, uint32_t sum)
+{
+	struct tcphdr tcphdr = {
+		.source = htons(9),
+		.dest = htons(9),
+		.fin = 1,
+		.doff = sizeof(tcphdr) / 4,
+	};
+	uint32_t tcp_sum = tun_sum(&tcphdr, sizeof(tcphdr));
+
+	tcphdr.check = tun_build_ip_check(sum + tcp_sum);
+	memcpy(dest, &tcphdr, sizeof(tcphdr));
+}
+
+static void tun_build_udphdr(void *dest, uint32_t sum)
+{
+	struct udphdr udphdr = {
+		.source = htons(9),
+		.dest = htons(9),
+		.len = htons(sizeof(udphdr)),
+	};
+	uint32_t udp_sum = tun_sum(&udphdr, sizeof(udphdr));
+
+	udphdr.check = tun_build_ip_check(sum + udp_sum);
+	memcpy(dest, &udphdr, sizeof(udphdr));
+}
+
+static bool tun_vnet_hash_check(int source_fd, const int *dest_fds,
+				const void *buffer, size_t len,
+				uint8_t flags,
+				uint16_t hash_report, uint32_t hash_value)
+{
+	size_t read_len = sizeof(struct virtio_net_hdr_v1_hash) + len;
+	struct virtio_net_hdr_v1_hash *read_buffer;
+	struct virtio_net_hdr_v1_hash hdr = {
+		.hdr = { .flags = flags },
+		.hash_value = htole32(hash_value),
+		.hash_report = htole16(hash_report)
+	};
+	int ret;
+	int txq = hash_report ? hash_value & 1 : 2;
+
+	if (write(source_fd, buffer, len) != len) {
+		perror("write");
+		return false;
+	}
+
+	read_buffer = malloc(read_len);
+	if (!read_buffer) {
+		perror("malloc");
+		return false;
+	}
+
+	ret = read(dest_fds[txq], read_buffer, read_len);
+	if (ret != read_len) {
+		perror("read");
+		free(read_buffer);
+		return false;
+	}
+
+	ret = !memcmp(read_buffer, &hdr, sizeof(*read_buffer)) &&
+	      !memcmp(read_buffer + 1, buffer, len);
+
+	free(read_buffer);
+	return ret;
+}
+
 FIXTURE(tun)
 {
 	char ifname[IFNAMSIZ];

@@ -112,10 +313,10 @@ FIXTURE_SETUP(tun)
 {
 	memset(self->ifname, 0, sizeof(self->ifname));
 
-	self->fd = tun_alloc(self->ifname);
+	self->fd = tun_alloc(self->ifname, 0);
 	ASSERT_GE(self->fd, 0);
 
-	self->fd2 = tun_alloc(self->ifname);
+	self->fd2 = tun_alloc(self->ifname, 0);
 	ASSERT_GE(self->fd2, 0);
 }
 

@@ -168,7 +369,7 @@ FIXTURE(tun_deleted)
 FIXTURE_SETUP(tun_deleted)
 {
 	self->ifname[0] = 0;
-	self->fd = tun_alloc(self->ifname);
+	self->fd = tun_alloc(self->ifname, 0);
 	ASSERT_LE(0, self->fd);
 
 	ASSERT_EQ(0, tun_delete(self->ifname))

@@ -233,4 +434,342 @@ TEST_F(tun_deleted, setvnethash)
 	EXPECT_EQ(EBADFD, errno);
 }
 
+FIXTURE(tun_vnet_hash)
+{
+	int local_fd;
+	int source_fd;
+	int dest_fds[3];
+};
+
+FIXTURE_SETUP(tun_vnet_hash)
+{
+	static const struct {
+		struct tun_vnet_hash hdr;
+		struct tun_vnet_hash_rss rss;
+		uint16_t rss_indirection_table[2];
+		uint8_t rss_key[40];
+	} vnet_hash = {
+		.hdr = {
+			.flags = TUN_VNET_HASH_REPORT | TUN_VNET_HASH_RSS,
+			.types = VIRTIO_NET_RSS_HASH_TYPE_IPv4 |
+				VIRTIO_NET_RSS_HASH_TYPE_TCPv4 |
+				VIRTIO_NET_RSS_HASH_TYPE_UDPv4 |
+				VIRTIO_NET_RSS_HASH_TYPE_IPv6 |
+				VIRTIO_NET_RSS_HASH_TYPE_TCPv6 |
+				VIRTIO_NET_RSS_HASH_TYPE_UDPv6
+		},
+		.rss = { .indirection_table_mask = 1, .unclassified_queue = 5 },
+		.rss_indirection_table = { 3, 4 },
+		.rss_key = {
+			0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2,
+			0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0,
+			0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4,
+			0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c,
+			0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa
+		}
+	};
+
+	struct {
+		struct virtio_net_hdr_v1_hash vnet_hdr;
+		struct ethhdr ethhdr;
+		struct arphdr arphdr;
+		unsigned char sender_hwaddr[6];
+		uint32_t sender_ipaddr;
+		unsigned char target_hwaddr[6];
+		uint32_t target_ipaddr;
+	} __packed packet = {
+		.ethhdr = {
+			.h_source = TUN_HWADDR_SOURCE,
+			.h_dest = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
+			.h_proto = htons(ETH_P_ARP)
+		},
+		.arphdr = {
+			.ar_hrd = htons(ARPHRD_ETHER),
+			.ar_pro = htons(ETH_P_IP),
+			.ar_hln = ETH_ALEN,
+			.ar_pln = 4,
+			.ar_op = htons(ARPOP_REQUEST)
+		},
+		.sender_hwaddr = TUN_HWADDR_DEST,
+		.sender_ipaddr = TUN_IPADDR_DEST,
+		.target_ipaddr = TUN_IPADDR_DEST
+	};
+
+	struct tun_vnet_hash cap;
+	char source_ifname[IFNAMSIZ] = "";
+	char dest_ifname[IFNAMSIZ] = "";
+	int i;
+
+	self->local_fd = socket(AF_LOCAL, SOCK_STREAM, 0);
+	ASSERT_LE(0, self->local_fd);
+
+	self->source_fd = tun_alloc(source_ifname, 0);
+	ASSERT_LE(0, self->source_fd) {
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	i = ioctl(self->source_fd, TUNGETVNETHASHCAP, &cap);
+	if (i == -1 && errno == EINVAL) {
+		EXPECT_EQ(0, close(self->local_fd));
+		SKIP(return, "TUNGETVNETHASHCAP not supported");
+	}
+
+	ASSERT_EQ(0, i)
+		EXPECT_EQ(0, close(self->local_fd));
+
+	if ((cap.flags & vnet_hash.hdr.flags) != vnet_hash.hdr.flags) {
+		EXPECT_EQ(0, close(self->local_fd));
+		SKIP(return, "Lacks some hash flag support");
+	}
+
+	if ((cap.types & vnet_hash.hdr.types) != vnet_hash.hdr.types) {
+		EXPECT_EQ(0, close(self->local_fd));
+		SKIP(return, "Lacks some hash type support");
+	}
+
+	ASSERT_TRUE(tun_set_flags(self->local_fd, source_ifname, IFF_UP))
+		EXPECT_EQ(0, close(self->local_fd));
+
+	self->dest_fds[0] = tun_alloc(dest_ifname, IFF_VNET_HDR);
+	ASSERT_LE(0, self->dest_fds[0]) {
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	i = sizeof(struct virtio_net_hdr_v1_hash);
+	ASSERT_EQ(0, ioctl(self->dest_fds[0], TUNSETVNETHDRSZ, &i)) {
+		EXPECT_EQ(0, close(self->dest_fds[0]));
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	i = 1;
+	ASSERT_EQ(0, ioctl(self->dest_fds[0], TUNSETVNETLE, &i)) {
+		EXPECT_EQ(0, close(self->dest_fds[0]));
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	ASSERT_TRUE(tun_set_flags(self->local_fd, dest_ifname, IFF_UP)) {
+		EXPECT_EQ(0, close(self->dest_fds[0]));
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	ASSERT_EQ(sizeof(packet),
+		  write(self->dest_fds[0], &packet, sizeof(packet))) {
+		EXPECT_EQ(0, close(self->dest_fds[0]));
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	ASSERT_EQ(0, ioctl(self->dest_fds[0], TUNSETVNETHASH, &vnet_hash)) {
+		EXPECT_EQ(0, close(self->dest_fds[0]));
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	for (i = 1; i < ARRAY_SIZE(self->dest_fds); i++) {
+		self->dest_fds[i] = tun_alloc(dest_ifname, IFF_VNET_HDR);
+		ASSERT_LE(0, self->dest_fds[i]) {
+			while (i) {
+				i--;
+				EXPECT_EQ(0, close(self->local_fd));
+			}
+
+			EXPECT_EQ(0, close(self->source_fd));
+			EXPECT_EQ(0, close(self->local_fd));
+		}
+	}
+
+	ASSERT_EQ(0, ioctl(self->local_fd, SIOCBRADDBR, "xbridge")) {
+		EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge"));
+
+		for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++)
+			EXPECT_EQ(0, close(self->dest_fds[i]));
+
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	ASSERT_TRUE(tun_add_to_bridge(self->local_fd, source_ifname)) {
+		EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge"));
+
+		for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++)
+			EXPECT_EQ(0, close(self->dest_fds[i]));
+
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	ASSERT_TRUE(tun_add_to_bridge(self->local_fd, dest_ifname)) {
+		EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge"));
+
+		for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++)
+			EXPECT_EQ(0, close(self->dest_fds[i]));
+
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	ASSERT_TRUE(tun_set_flags(self->local_fd, "xbridge", IFF_UP)) {
+		EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge"));
+
+		for (i = 0; i < ARRAY_SIZE(self->dest_fds); i++)
+			EXPECT_EQ(0, close(self->dest_fds[i]));
+
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+}
+
+FIXTURE_TEARDOWN(tun_vnet_hash)
+{
+	ASSERT_TRUE(tun_set_flags(self->local_fd, "xbridge", 0)) {
+		for (size_t i = 0; i < ARRAY_SIZE(self->dest_fds); i++)
+			EXPECT_EQ(0, close(self->dest_fds[i]));
+
+		EXPECT_EQ(0, close(self->source_fd));
+		EXPECT_EQ(0, close(self->local_fd));
+	}
+
+	EXPECT_EQ(0, ioctl(self->local_fd, SIOCBRDELBR, "xbridge"));
+
+	for (size_t i = 0; i < ARRAY_SIZE(self->dest_fds); i++)
+		EXPECT_EQ(0, close(self->dest_fds[i]));
+
+	EXPECT_EQ(0, close(self->source_fd));
+	EXPECT_EQ(0, close(self->local_fd));
+}
+
+TEST_F(tun_vnet_hash, unclassified)
+{
+	struct {
+		struct ethhdr ethhdr;
+		struct iphdr iphdr;
+	} __packed packet;
+
+	tun_build_ethhdr(&packet.ethhdr, ETH_P_LOOPBACK);
+
+	EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds,
+					&packet, sizeof(packet), 0,
+					VIRTIO_NET_HASH_REPORT_NONE, 0));
+}
+
+TEST_F(tun_vnet_hash, ipv4)
+{
+	struct {
+		struct ethhdr ethhdr;
+		struct iphdr iphdr;
+	} __packed packet;
+
+	tun_build_ethhdr(&packet.ethhdr, ETH_P_IP);
+	tun_build_iphdr(&packet.iphdr, 0, 253);
+
+	EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds,
+					&packet, sizeof(packet), 0,
+					VIRTIO_NET_HASH_REPORT_IPv4,
+					0x6e45d952));
+}
+
+TEST_F(tun_vnet_hash, tcpv4)
+{
+	struct {
+		struct ethhdr ethhdr;
+		struct iphdr iphdr;
+		struct tcphdr tcphdr;
+	} __packed packet;
+
+	tun_build_ethhdr(&packet.ethhdr, ETH_P_IP);
+	tun_build_iphdr(&packet.iphdr, sizeof(struct tcphdr), IPPROTO_TCP);
+
+	tun_build_tcphdr(&packet.tcphdr,
+			 tun_build_ip_pseudo_sum(&packet.iphdr));
+
+	EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds,
+					&packet, sizeof(packet),
+					VIRTIO_NET_HDR_F_DATA_VALID,
+					VIRTIO_NET_HASH_REPORT_TCPv4,
+					0xfb63539a));
+}
+
+TEST_F(tun_vnet_hash, udpv4)
+{
+	struct {
+		struct ethhdr ethhdr;
+		struct iphdr iphdr;
+		struct udphdr udphdr;
+	} __packed packet;
+
+	tun_build_ethhdr(&packet.ethhdr, ETH_P_IP);
+	tun_build_iphdr(&packet.iphdr, sizeof(struct udphdr), IPPROTO_UDP);
+
+	tun_build_udphdr(&packet.udphdr,
+			 tun_build_ip_pseudo_sum(&packet.iphdr));
+
+	EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds,
+					&packet, sizeof(packet),
+					VIRTIO_NET_HDR_F_DATA_VALID,
+					VIRTIO_NET_HASH_REPORT_UDPv4,
+					0xfb63539a));
+}
+
+TEST_F(tun_vnet_hash, ipv6)
+{
+	struct {
+		struct ethhdr ethhdr;
+		struct ipv6hdr ipv6hdr;
+	} __packed packet;
+
+	tun_build_ethhdr(&packet.ethhdr, ETH_P_IPV6);
+	tun_build_ipv6hdr(&packet.ipv6hdr, 0, 253);
+
+	EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds,
+					&packet, sizeof(packet), 0,
+					VIRTIO_NET_HASH_REPORT_IPv6,
+					0xd6eb560f));
+}
+
+TEST_F(tun_vnet_hash, tcpv6)
+{
+	struct {
+		struct ethhdr ethhdr;
+		struct ipv6hdr ipv6hdr;
+		struct tcphdr tcphdr;
+	} __packed packet;
+
+	tun_build_ethhdr(&packet.ethhdr, ETH_P_IPV6);
+	tun_build_ipv6hdr(&packet.ipv6hdr, sizeof(struct tcphdr), IPPROTO_TCP);
+
+	tun_build_tcphdr(&packet.tcphdr,
+			 tun_build_ipv6_pseudo_sum(&packet.ipv6hdr));
+
+	EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds,
+					&packet, sizeof(packet),
+					VIRTIO_NET_HDR_F_DATA_VALID,
+					VIRTIO_NET_HASH_REPORT_TCPv6,
+					0xc2b9f251));
+}
+
+TEST_F(tun_vnet_hash, udpv6)
+{
+	struct {
+		struct ethhdr ethhdr;
+		struct ipv6hdr ipv6hdr;
+		struct udphdr udphdr;
+	} __packed packet;
+
+	tun_build_ethhdr(&packet.ethhdr, ETH_P_IPV6);
+	tun_build_ipv6hdr(&packet.ipv6hdr, sizeof(struct udphdr), IPPROTO_UDP);
+
+	tun_build_udphdr(&packet.udphdr,
+			 tun_build_ipv6_pseudo_sum(&packet.ipv6hdr));
+
+	EXPECT_TRUE(tun_vnet_hash_check(self->source_fd, self->dest_fds,
+					&packet, sizeof(packet),
+					VIRTIO_NET_HDR_F_DATA_VALID,
+					VIRTIO_NET_HASH_REPORT_UDPv6,
+					0xc2b9f251));
+}
+
 TEST_HARNESS_MAIN