--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <net/if.h>
+#include <linux/if_tun.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/virtio_net.h>
+#include <netinet/ip.h>
+#include <netinet/udp.h>
+#include "../kselftest_harness.h"
+
+static const char param_dev_tap_name[] = "xmacvtap0";
+static const char param_dev_dummy_name[] = "xdummy0";
+static unsigned char param_hwaddr_src[] = { 0x00, 0xfe, 0x98, 0x14, 0x22, 0x42 };
+static unsigned char param_hwaddr_dest[] = {
+ 0x00, 0xfe, 0x98, 0x94, 0xd2, 0x43
+};
+
+#define MAX_RTNL_PAYLOAD (2048)
+#define PKT_DATA 0xCB
+#define TEST_PACKET_SZ (sizeof(struct virtio_net_hdr) + ETH_HLEN + ETH_MAX_MTU)
+
+static struct rtattr *rtattr_add(struct nlmsghdr *nh, unsigned short type,
+ unsigned short len)
+{
+ struct rtattr *rta =
+ (struct rtattr *)((uint8_t *)nh + RTA_ALIGN(nh->nlmsg_len));
+ rta->rta_type = type;
+ rta->rta_len = RTA_LENGTH(len);
+ nh->nlmsg_len = RTA_ALIGN(nh->nlmsg_len) + RTA_ALIGN(rta->rta_len);
+ return rta;
+}
+
+static struct rtattr *rtattr_begin(struct nlmsghdr *nh, unsigned short type)
+{
+ return rtattr_add(nh, type, 0);
+}
+
+static void rtattr_end(struct nlmsghdr *nh, struct rtattr *attr)
+{
+ uint8_t *end = (uint8_t *)nh + nh->nlmsg_len;
+
+ attr->rta_len = end - (uint8_t *)attr;
+}
+
+static struct rtattr *rtattr_add_str(struct nlmsghdr *nh, unsigned short type,
+ const char *s)
+{
+ struct rtattr *rta = rtattr_add(nh, type, strlen(s));
+
+ memcpy(RTA_DATA(rta), s, strlen(s));
+ return rta;
+}
+
+static struct rtattr *rtattr_add_strsz(struct nlmsghdr *nh, unsigned short type,
+ const char *s)
+{
+ struct rtattr *rta = rtattr_add(nh, type, strlen(s) + 1);
+
+ strcpy(RTA_DATA(rta), s);
+ return rta;
+}
+
+static struct rtattr *rtattr_add_any(struct nlmsghdr *nh, unsigned short type,
+ const void *arr, size_t len)
+{
+ struct rtattr *rta = rtattr_add(nh, type, len);
+
+ memcpy(RTA_DATA(rta), arr, len);
+ return rta;
+}
+
+static int dev_create(const char *dev, const char *link_type,
+ int (*fill_rtattr)(struct nlmsghdr *nh),
+ int (*fill_info_data)(struct nlmsghdr *nh))
+{
+ struct {
+ struct nlmsghdr nh;
+ struct ifinfomsg info;
+ unsigned char data[MAX_RTNL_PAYLOAD];
+ } req;
+ struct rtattr *link_info, *info_data;
+ int ret, rtnl;
+
+ rtnl = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
+ if (rtnl < 0) {
+ fprintf(stderr, "%s: socket %s\n", __func__, strerror(errno));
+ return 1;
+ }
+
+ memset(&req, 0, sizeof(req));
+ req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.info));
+ req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE;
+ req.nh.nlmsg_type = RTM_NEWLINK;
+
+ req.info.ifi_family = AF_UNSPEC;
+ req.info.ifi_type = 1;
+ req.info.ifi_index = 0;
+ req.info.ifi_flags = IFF_BROADCAST | IFF_UP;
+ req.info.ifi_change = 0xffffffff;
+
+ rtattr_add_str(&req.nh, IFLA_IFNAME, dev);
+
+ if (fill_rtattr) {
+ ret = fill_rtattr(&req.nh);
+ if (ret)
+ return ret;
+ }
+
+ link_info = rtattr_begin(&req.nh, IFLA_LINKINFO);
+
+ rtattr_add_strsz(&req.nh, IFLA_INFO_KIND, link_type);
+
+ if (fill_info_data) {
+ info_data = rtattr_begin(&req.nh, IFLA_INFO_DATA);
+ ret = fill_info_data(&req.nh);
+ if (ret)
+ return ret;
+ rtattr_end(&req.nh, info_data);
+ }
+
+ rtattr_end(&req.nh, link_info);
+
+ ret = send(rtnl, &req, req.nh.nlmsg_len, 0);
+ if (ret < 0)
+ fprintf(stderr, "%s: send %s\n", __func__, strerror(errno));
+ ret = (unsigned int)ret != req.nh.nlmsg_len;
+
+ close(rtnl);
+ return ret;
+}
+
+static int dev_delete(const char *dev)
+{
+ struct {
+ struct nlmsghdr nh;
+ struct ifinfomsg info;
+ unsigned char data[MAX_RTNL_PAYLOAD];
+ } req;
+ int ret, rtnl;
+
+ rtnl = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
+ if (rtnl < 0) {
+ fprintf(stderr, "%s: socket %s\n", __func__, strerror(errno));
+ return 1;
+ }
+
+ memset(&req, 0, sizeof(req));
+ req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.info));
+ req.nh.nlmsg_flags = NLM_F_REQUEST;
+ req.nh.nlmsg_type = RTM_DELLINK;
+
+ req.info.ifi_family = AF_UNSPEC;
+
+ rtattr_add_str(&req.nh, IFLA_IFNAME, dev);
+
+ ret = send(rtnl, &req, req.nh.nlmsg_len, 0);
+ if (ret < 0)
+ fprintf(stderr, "%s: send %s\n", __func__, strerror(errno));
+
+ ret = (unsigned int)ret != req.nh.nlmsg_len;
+
+ close(rtnl);
+ return ret;
+}
+
+static int macvtap_fill_rtattr(struct nlmsghdr *nh)
+{
+ int ifindex;
+
+ ifindex = if_nametoindex(param_dev_dummy_name);
+ if (ifindex == 0) {
+ fprintf(stderr, "%s: ifindex %s\n", __func__, strerror(errno));
+ return -errno;
+ }
+
+ rtattr_add_any(nh, IFLA_LINK, &ifindex, sizeof(ifindex));
+ rtattr_add_any(nh, IFLA_ADDRESS, param_hwaddr_src, ETH_ALEN);
+
+ return 0;
+}
+
+static int opentap(const char *devname)
+{
+ int ifindex;
+ char buf[256];
+ int fd;
+ struct ifreq ifr;
+
+ ifindex = if_nametoindex(devname);
+ if (ifindex == 0) {
+ fprintf(stderr, "%s: ifindex %s\n", __func__, strerror(errno));
+ return -errno;
+ }
+
+ sprintf(buf, "/dev/tap%d", ifindex);
+ fd = open(buf, O_RDWR | O_NONBLOCK);
+ if (fd < 0) {
+ fprintf(stderr, "%s: open %s\n", __func__, strerror(errno));
+ return -errno;
+ }
+
+ memset(&ifr, 0, sizeof(ifr));
+ strcpy(ifr.ifr_name, devname);
+ ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR | IFF_MULTI_QUEUE;
+ if (ioctl(fd, TUNSETIFF, &ifr, sizeof(ifr)) < 0)
+ return -errno;
+ return fd;
+}
+
+size_t build_eth(uint8_t *buf, uint16_t proto)
+{
+ struct ethhdr *eth = (struct ethhdr *)buf;
+
+ eth->h_proto = htons(proto);
+ memcpy(eth->h_source, param_hwaddr_src, ETH_ALEN);
+ memcpy(eth->h_dest, param_hwaddr_dest, ETH_ALEN);
+
+ return ETH_HLEN;
+}
+
+static uint32_t add_csum(const uint8_t *buf, int len)
+{
+ uint32_t sum = 0;
+ uint16_t *sbuf = (uint16_t *)buf;
+
+ while (len > 1) {
+ sum += *sbuf++;
+ len -= 2;
+ }
+
+ if (len)
+ sum += *(uint8_t *)sbuf;
+
+ return sum;
+}
+
+static uint16_t finish_ip_csum(uint32_t sum)
+{
+ uint16_t lo = sum & 0xffff;
+ uint16_t hi = sum >> 16;
+
+ return ~(lo + hi);
+
+}
+
+static uint16_t build_ip_csum(const uint8_t *buf, int len,
+ uint32_t sum)
+{
+ sum += add_csum(buf, len);
+ return finish_ip_csum(sum);
+}
+
+static int build_ipv4_header(uint8_t *buf, int payload_len)
+{
+ struct iphdr *iph = (struct iphdr *)buf;
+
+ iph->ihl = 5;
+ iph->version = 4;
+ iph->ttl = 8;
+ iph->tot_len =
+ htons(sizeof(*iph) + sizeof(struct udphdr) + payload_len);
+ iph->id = htons(1337);
+ iph->protocol = IPPROTO_UDP;
+ iph->saddr = htonl((172 << 24) | (17 << 16) | 2);
+ iph->daddr = htonl((172 << 24) | (17 << 16) | 1);
+ iph->check = build_ip_csum(buf, iph->ihl << 2, 0);
+
+ return iph->ihl << 2;
+}
+
+static int build_udp_packet(uint8_t *buf, int payload_len, bool csum_off)
+{
+ const int ip4alen = sizeof(uint32_t);
+ struct udphdr *udph = (struct udphdr *)buf;
+ int len = sizeof(*udph) + payload_len;
+ uint32_t sum = 0;
+
+ udph->source = htons(22);
+ udph->dest = htons(58822);
+ udph->len = htons(len);
+
+ memset(buf + sizeof(struct udphdr), PKT_DATA, payload_len);
+
+ sum = add_csum(buf - 2 * ip4alen, 2 * ip4alen);
+ sum += htons(IPPROTO_UDP) + udph->len;
+
+ if (!csum_off)
+ sum += add_csum(buf, len);
+
+ udph->check = finish_ip_csum(sum);
+
+ return sizeof(*udph) + payload_len;
+}
+
+size_t build_test_packet_valid_udp_gso(uint8_t *buf, size_t payload_len)
+{
+ uint8_t *cur = buf;
+ struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf;
+
+ vh->hdr_len = ETH_HLEN + sizeof(struct iphdr) + sizeof(struct udphdr);
+ vh->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+ vh->csum_start = ETH_HLEN + sizeof(struct iphdr);
+ vh->csum_offset = __builtin_offsetof(struct udphdr, check);
+ vh->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+ vh->gso_size = ETH_DATA_LEN - sizeof(struct iphdr);
+ cur += sizeof(*vh);
+
+ cur += build_eth(cur, ETH_P_IP);
+ cur += build_ipv4_header(cur, payload_len);
+ cur += build_udp_packet(cur, payload_len, true);
+
+ return cur - buf;
+}
+
+size_t build_test_packet_valid_udp_csum(uint8_t *buf, size_t payload_len)
+{
+ uint8_t *cur = buf;
+ struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf;
+
+ vh->flags = VIRTIO_NET_HDR_F_DATA_VALID;
+ vh->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+ cur += sizeof(*vh);
+
+ cur += build_eth(cur, ETH_P_IP);
+ cur += build_ipv4_header(cur, payload_len);
+ cur += build_udp_packet(cur, payload_len, false);
+
+ return cur - buf;
+}
+
+size_t build_test_packet_crash_tap_invalid_eth_proto(uint8_t *buf,
+ size_t payload_len)
+{
+ uint8_t *cur = buf;
+ struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf;
+
+ vh->hdr_len = ETH_HLEN + sizeof(struct iphdr) + sizeof(struct udphdr);
+ vh->flags = 0;
+ vh->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+ vh->gso_size = ETH_DATA_LEN - sizeof(struct iphdr);
+ cur += sizeof(*vh);
+
+ cur += build_eth(cur, 0);
+ cur += sizeof(struct iphdr) + sizeof(struct udphdr);
+ cur += build_ipv4_header(cur, payload_len);
+ cur += build_udp_packet(cur, payload_len, true);
+ cur += payload_len;
+
+ return cur - buf;
+}
+
+FIXTURE(tap)
+{
+ int fd;
+};
+
+FIXTURE_SETUP(tap)
+{
+ int ret;
+
+ ret = dev_create(param_dev_dummy_name, "dummy", NULL, NULL);
+ EXPECT_EQ(ret, 0);
+
+ ret = dev_create(param_dev_tap_name, "macvtap", macvtap_fill_rtattr,
+ NULL);
+ EXPECT_EQ(ret, 0);
+
+ self->fd = opentap(param_dev_tap_name);
+ ASSERT_GE(self->fd, 0);
+}
+
+FIXTURE_TEARDOWN(tap)
+{
+ int ret;
+
+ if (self->fd != -1)
+ close(self->fd);
+
+ ret = dev_delete(param_dev_tap_name);
+ EXPECT_EQ(ret, 0);
+
+ ret = dev_delete(param_dev_dummy_name);
+ EXPECT_EQ(ret, 0);
+}
+
+TEST_F(tap, test_packet_valid_udp_gso)
+{
+ uint8_t pkt[TEST_PACKET_SZ];
+ size_t off;
+ int ret;
+
+ memset(pkt, 0, sizeof(pkt));
+ off = build_test_packet_valid_udp_gso(pkt, 1021);
+ ret = write(self->fd, pkt, off);
+ ASSERT_EQ(ret, off);
+}
+
+TEST_F(tap, test_packet_valid_udp_csum)
+{
+ uint8_t pkt[TEST_PACKET_SZ];
+ size_t off;
+ int ret;
+
+ memset(pkt, 0, sizeof(pkt));
+ off = build_test_packet_valid_udp_csum(pkt, 1024);
+ ret = write(self->fd, pkt, off);
+ ASSERT_EQ(ret, off);
+}
+
+TEST_F(tap, test_packet_crash_tap_invalid_eth_proto)
+{
+ uint8_t pkt[TEST_PACKET_SZ];
+ size_t off;
+ int ret;
+
+ memset(pkt, 0, sizeof(pkt));
+ off = build_test_packet_crash_tap_invalid_eth_proto(pkt, 1024);
+ ret = write(self->fd, pkt, off);
+ ASSERT_EQ(ret, -1);
+ ASSERT_EQ(errno, EINVAL);
+}
+
+TEST_HARNESS_MAIN
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