// https://syzkaller.appspot.com/bug?id=a16dc073dda2f14b653fe06dda971f87ecf9296a
// autogenerated by syzkaller (http://github.com/google/syzkaller)

#define _GNU_SOURCE

#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/if.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <net/if_arp.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <unistd.h>

const int kFailStatus = 67;
const int kRetryStatus = 69;

__attribute__((noreturn)) static void doexit(int status)
{
  volatile unsigned i;
  syscall(__NR_exit_group, status);
  for (i = 0;; i++) {
  }
}

__attribute__((noreturn)) static void fail(const char* msg, ...)
{
  int e = errno;
  fflush(stdout);
  va_list args;
  va_start(args, msg);
  vfprintf(stderr, msg, args);
  va_end(args);
  fprintf(stderr, " (errno %d)\n", e);
  doexit((e == ENOMEM || e == EAGAIN) ? kRetryStatus : kFailStatus);
}

#define BITMASK_LEN(type, bf_len) (type)((1ull << (bf_len)) - 1)

#define BITMASK_LEN_OFF(type, bf_off, bf_len)                          \
  (type)(BITMASK_LEN(type, (bf_len)) << (bf_off))

#define STORE_BY_BITMASK(type, addr, val, bf_off, bf_len)              \
  if ((bf_off) == 0 && (bf_len) == 0) {                                \
    *(type*)(addr) = (type)(val);                                      \
  } else {                                                             \
    type new_val = *(type*)(addr);                                     \
    new_val &= ~BITMASK_LEN_OFF(type, (bf_off), (bf_len));             \
    new_val |= ((type)(val)&BITMASK_LEN(type, (bf_len))) << (bf_off);  \
    *(type*)(addr) = new_val;                                          \
  }

static void vsnprintf_check(char* str, size_t size, const char* format,
                            va_list args)
{
  int rv;

  rv = vsnprintf(str, size, format, args);
  if (rv < 0)
    fail("tun: snprintf failed");
  if ((size_t)rv >= size)
    fail("tun: string '%s...' doesn't fit into buffer", str);
}

static void snprintf_check(char* str, size_t size, const char* format,
                           ...)
{
  va_list args;

  va_start(args, format);
  vsnprintf_check(str, size, format, args);
  va_end(args);
}

#define COMMAND_MAX_LEN 128

static void execute_command(const char* format, ...)
{
  va_list args;
  char command[COMMAND_MAX_LEN];
  int rv;

  va_start(args, format);

  vsnprintf_check(command, sizeof(command), format, args);
  rv = system(command);
  if (rv != 0)
    fail("tun: command \"%s\" failed with code %d", &command[0], rv);

  va_end(args);
}

static int tunfd = -1;

#define SYZ_TUN_MAX_PACKET_SIZE 1000

#define MAX_PIDS 32
#define ADDR_MAX_LEN 32

#define LOCAL_MAC "aa:aa:aa:aa:aa:%02hx"
#define REMOTE_MAC "bb:bb:bb:bb:bb:%02hx"

#define LOCAL_IPV4 "172.20.%d.170"
#define REMOTE_IPV4 "172.20.%d.187"

#define LOCAL_IPV6 "fe80::%02hxaa"
#define REMOTE_IPV6 "fe80::%02hxbb"

static void initialize_tun(uint64_t pid)
{
  if (pid >= MAX_PIDS)
    fail("tun: no more than %d executors", MAX_PIDS);
  int id = pid;

  tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
  if (tunfd == -1)
    fail("tun: can't open /dev/net/tun");

  char iface[IFNAMSIZ];
  snprintf_check(iface, sizeof(iface), "syz%d", id);

  struct ifreq ifr;
  memset(&ifr, 0, sizeof(ifr));
  strncpy(ifr.ifr_name, iface, IFNAMSIZ);
  ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0)
    fail("tun: ioctl(TUNSETIFF) failed");

  char local_mac[ADDR_MAX_LEN];
  snprintf_check(local_mac, sizeof(local_mac), LOCAL_MAC, id);
  char remote_mac[ADDR_MAX_LEN];
  snprintf_check(remote_mac, sizeof(remote_mac), REMOTE_MAC, id);

  char local_ipv4[ADDR_MAX_LEN];
  snprintf_check(local_ipv4, sizeof(local_ipv4), LOCAL_IPV4, id);
  char remote_ipv4[ADDR_MAX_LEN];
  snprintf_check(remote_ipv4, sizeof(remote_ipv4), REMOTE_IPV4, id);

  char local_ipv6[ADDR_MAX_LEN];
  snprintf_check(local_ipv6, sizeof(local_ipv6), LOCAL_IPV6, id);
  char remote_ipv6[ADDR_MAX_LEN];
  snprintf_check(remote_ipv6, sizeof(remote_ipv6), REMOTE_IPV6, id);

  execute_command("sysctl -w net.ipv6.conf.%s.accept_dad=0", iface);

  execute_command("sysctl -w net.ipv6.conf.%s.router_solicitations=0",
                  iface);

  execute_command("ip link set dev %s address %s", iface, local_mac);
  execute_command("ip addr add %s/24 dev %s", local_ipv4, iface);
  execute_command("ip -6 addr add %s/120 dev %s", local_ipv6, iface);
  execute_command("ip neigh add %s lladdr %s dev %s nud permanent",
                  remote_ipv4, remote_mac, iface);
  execute_command("ip -6 neigh add %s lladdr %s dev %s nud permanent",
                  remote_ipv6, remote_mac, iface);
  execute_command("ip link set dev %s up", iface);
}

static void setup_tun(uint64_t pid, bool enable_tun)
{
  if (enable_tun)
    initialize_tun(pid);
}

struct csum_inet {
  uint32_t acc;
};

static void csum_inet_init(struct csum_inet* csum)
{
  csum->acc = 0;
}

static void csum_inet_update(struct csum_inet* csum,
                             const uint8_t* data, size_t length)
{
  if (length == 0)
    return;

  size_t i;
  for (i = 0; i < length - 1; i += 2)
    csum->acc += *(uint16_t*)&data[i];

  if (length & 1)
    csum->acc += (uint16_t)data[length - 1];

  while (csum->acc > 0xffff)
    csum->acc = (csum->acc & 0xffff) + (csum->acc >> 16);
}

static uint16_t csum_inet_digest(struct csum_inet* csum)
{
  return ~csum->acc;
}

static uintptr_t syz_emit_ethernet(uintptr_t a0, uintptr_t a1)
{

  if (tunfd < 0)
    return (uintptr_t)-1;

  int64_t length = a0;
  char* data = (char*)a1;
  return write(tunfd, data, length);
}

long r[117];
void* thr(void* arg)
{
  switch ((long)arg) {
  case 0:
    r[0] = syscall(__NR_mmap, 0x20000000ul, 0xf02000ul, 0x3ul, 0x32ul,
                   r[0], 0x0ul);
    break;
  case 1:
    r[1] = syscall(__NR_socket, 0x2ul, 0x2ul, 0x0ul);
    break;
  case 2:
    *(uint16_t*)0x20afbff0 = (uint16_t)0x2;
    *(uint16_t*)0x20afbff2 = (uint16_t)0x224e;
    *(uint32_t*)0x20afbff4 = (uint32_t)0x10000e0;
    *(uint8_t*)0x20afbff8 = (uint8_t)0x0;
    *(uint8_t*)0x20afbff9 = (uint8_t)0x0;
    *(uint8_t*)0x20afbffa = (uint8_t)0x0;
    *(uint8_t*)0x20afbffb = (uint8_t)0x0;
    *(uint8_t*)0x20afbffc = (uint8_t)0x0;
    *(uint8_t*)0x20afbffd = (uint8_t)0x0;
    *(uint8_t*)0x20afbffe = (uint8_t)0x0;
    *(uint8_t*)0x20afbfff = (uint8_t)0x0;
    r[13] = syscall(__NR_bind, r[1], 0x20afbff0ul, 0x10ul);
    break;
  case 3:
    *(uint8_t*)0x2005cfbe = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfbf = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc0 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc1 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc2 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc3 = (uint8_t)0x0;
    *(uint8_t*)0x2005cfc4 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc5 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc6 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc7 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc8 = (uint8_t)0xbb;
    *(uint8_t*)0x2005cfc9 = (uint8_t)0x0;
    *(uint16_t*)0x2005cfca = (uint16_t)0x8;
    STORE_BY_BITMASK(uint8_t, 0x2005cfcc, 0xb, 0, 4);
    STORE_BY_BITMASK(uint8_t, 0x2005cfcc, 0x4, 4, 4);
    STORE_BY_BITMASK(uint8_t, 0x2005cfcd, 0x0, 0, 2);
    STORE_BY_BITMASK(uint8_t, 0x2005cfcd, 0x0, 2, 6);
    *(uint16_t*)0x2005cfce = (uint16_t)0x3400;
    *(uint16_t*)0x2005cfd0 = (uint16_t)0x0;
    *(uint16_t*)0x2005cfd2 = (uint16_t)0x0;
    *(uint8_t*)0x2005cfd4 = (uint8_t)0x0;
    *(uint8_t*)0x2005cfd5 = (uint8_t)0x11;
    *(uint16_t*)0x2005cfd6 = (uint16_t)0x0;
    *(uint8_t*)0x2005cfd8 = (uint8_t)0xac;
    *(uint8_t*)0x2005cfd9 = (uint8_t)0x14;
    *(uint8_t*)0x2005cfda = (uint8_t)0x0;
    *(uint8_t*)0x2005cfdb = (uint8_t)0xbb;
    *(uint32_t*)0x2005cfdc = (uint32_t)0x10000e0;
    *(uint8_t*)0x2005cfe0 = (uint8_t)0x44;
    *(uint8_t*)0x2005cfe1 = (uint8_t)0x18;
    *(uint8_t*)0x2005cfe2 = (uint8_t)0x9;
    STORE_BY_BITMASK(uint8_t, 0x2005cfe3, 0x3, 0, 4);
    STORE_BY_BITMASK(uint8_t, 0x2005cfe3, 0x2, 4, 4);
    *(uint8_t*)0x2005cfe4 = (uint8_t)0xac;
    *(uint8_t*)0x2005cfe5 = (uint8_t)0x14;
    *(uint8_t*)0x2005cfe6 = (uint8_t)0x0;
    *(uint8_t*)0x2005cfe7 = (uint8_t)0xbb;
    *(uint32_t*)0x2005cfe8 = (uint32_t)0x6000000;
    *(uint32_t*)0x2005cfec = (uint32_t)0x1000100;
    *(uint32_t*)0x2005cff0 = (uint32_t)0xffffffff;
    *(uint32_t*)0x2005cff4 = (uint32_t)0x6000000;
    *(uint16_t*)0x2005cff8 = (uint16_t)0x204e;
    *(uint16_t*)0x2005cffa = (uint16_t)0x224e;
    *(uint16_t*)0x2005cffc = (uint16_t)0x800;
    *(uint16_t*)0x2005cffe = (uint16_t)0x0;
    struct csum_inet csum_59;
    csum_inet_init(&csum_59);
    csum_inet_update(&csum_59, (const uint8_t*)0x2005cfd8, 4);
    csum_inet_update(&csum_59, (const uint8_t*)0x2005cfdc, 4);
    uint16_t csum_59_chunk_2 = 0x1100;
    csum_inet_update(&csum_59, (const uint8_t*)&csum_59_chunk_2, 2);
    uint16_t csum_59_chunk_3 = 0x800;
    csum_inet_update(&csum_59, (const uint8_t*)&csum_59_chunk_3, 2);
    csum_inet_update(&csum_59, (const uint8_t*)0x2005cff8, 8);
    *(uint16_t*)0x2005cffe = csum_inet_digest(&csum_59);
    struct csum_inet csum_60;
    csum_inet_init(&csum_60);
    csum_inet_update(&csum_60, (const uint8_t*)0x2005cfcc, 44);
    *(uint16_t*)0x2005cfd6 = csum_inet_digest(&csum_60);
    r[61] = syz_emit_ethernet(0x42ul, 0x2005cfbeul);
    break;
  case 4:
    *(uint16_t*)0x20efeff0 = (uint16_t)0x2;
    *(uint16_t*)0x20efeff2 = (uint16_t)0x234e;
    *(uint8_t*)0x20efeff4 = (uint8_t)0xac;
    *(uint8_t*)0x20efeff5 = (uint8_t)0x14;
    *(uint8_t*)0x20efeff6 = (uint8_t)0x0;
    *(uint8_t*)0x20efeff7 = (uint8_t)0xaa;
    *(uint8_t*)0x20efeff8 = (uint8_t)0x0;
    *(uint8_t*)0x20efeff9 = (uint8_t)0x0;
    *(uint8_t*)0x20efeffa = (uint8_t)0x0;
    *(uint8_t*)0x20efeffb = (uint8_t)0x0;
    *(uint8_t*)0x20efeffc = (uint8_t)0x0;
    *(uint8_t*)0x20efeffd = (uint8_t)0x0;
    *(uint8_t*)0x20efeffe = (uint8_t)0x0;
    *(uint8_t*)0x20efefff = (uint8_t)0x0;
    r[76] = syscall(__NR_recvfrom, r[1], 0x20efdf4dul, 0x0ul, 0x10042ul,
                    0x20efeff0ul, 0x10ul);
    break;
  case 5:
    memcpy((void*)0x20ec0000,
           "\xc1\x17\x7c\x63\x84\xfc\x5f\x3e\xfd\x9f\x92\x8d\x95\x84"
           "\xb0\xbd\xb7\xcc\x73\x2c\x5b\xb8\xfe\xc5\x8b\x78\xd3\x9e"
           "\xd5\x69\xc8\xd9\x9b\xd5\xda\x1e\x5a\x53\x0c\xa8\xa5\x8d"
           "\xd8\x07\x77\xf1\xd1\xef\x43\x96\x88\x04\x59\x5f\x79\xc8"
           "\x95\xab\x76\x79\x4d\x66\x63\xb7\x1a\xee\x44\x71\x0d\x53"
           "\xdd\xb8\x30\x2c\x5a\x45\xdb\x3f\xfc\xf2\xf2\x54\x3d\x7f"
           "\x1c\x05\xe7\x0f\xc0\xbf\xab\xb4\xa4\xfa\x22\x50\x9b\x15"
           "\x5f\x21\xe6\x77\x75\x4e\x1b\x81\xa6\xc9\xdf\x3c\x8b\x21"
           "\x40\xbb\x2d\xb8\x30\xf4\x38\x4d\x95\x58\xf2\x1c\x92\xaa"
           "\xb5\x56\xe1\xa7\x00\x66\x67\x77\x7d\x30\xdd\x36\xc8\x33"
           "\xc3\xfc\x03",
           143);
    r[78] = syscall(__NR_setsockopt, r[1], 0x0ul, 0x7ul, 0x20ec0000ul,
                    0x8ful);
    break;
  case 6:
    r[79] = syscall(__NR_socket, 0x10ul, 0x3ul, 0xful);
    break;
  case 7:
    *(uint32_t*)0x20bf9000 = (uint32_t)0x3;
    *(uint16_t*)0x20bf9008 = (uint16_t)0x2;
    *(uint16_t*)0x20bf900a = (uint16_t)0x204e;
    *(uint32_t*)0x20bf900c = (uint32_t)0x10000e0;
    *(uint8_t*)0x20bf9010 = (uint8_t)0x0;
    *(uint8_t*)0x20bf9011 = (uint8_t)0x0;
    *(uint8_t*)0x20bf9012 = (uint8_t)0x0;
    *(uint8_t*)0x20bf9013 = (uint8_t)0x0;
    *(uint8_t*)0x20bf9014 = (uint8_t)0x0;
    *(uint8_t*)0x20bf9015 = (uint8_t)0x0;
    *(uint8_t*)0x20bf9016 = (uint8_t)0x0;
    *(uint8_t*)0x20bf9017 = (uint8_t)0x0;
    *(uint64_t*)0x20bf9018 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9020 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9028 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9030 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9038 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9040 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9048 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9050 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9058 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9060 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9068 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9070 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9078 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9080 = (uint64_t)0x0;
    *(uint64_t*)0x20bf9088 = (uint64_t)0x0;
    r[107] = syscall(__NR_setsockopt, r[0], 0x0ul, 0x2aul, 0x20bf9000ul,
                     0x90ul);
    break;
  case 8:
    *(uint16_t*)0x20efefa0 = (uint16_t)0x27;
    *(uint32_t*)0x20efefa4 = (uint32_t)0x4;
    *(uint32_t*)0x20efefa8 = (uint32_t)0x4;
    *(uint32_t*)0x20efefac = (uint32_t)0x5;
    *(uint8_t*)0x20efefb0 = (uint8_t)0x2;
    *(uint8_t*)0x20efefb1 = (uint8_t)0x6;
    memcpy((void*)0x20efefb2,
           "\x7d\xa1\x29\x19\x03\xcc\x67\x2f\xa7\x82\xe1\xf8\x5d\xed"
           "\x83\x4f\x39\x8f\x94\xdd\x44\xf2\xae\xc1\x9e\x13\xcd\xb6"
           "\x7a\x88\x47\x7c\xb5\x64\x70\x88\x31\x70\x1f\x0e\xc4\x0c"
           "\x51\x4d\xae\x9a\x0d\xf2\xaf\x76\x16\xb5\xb0\xc5\xdf\x9b"
           "\x5b\x5d\x97\x1f\x45\x67\x8d",
           63);
    *(uint64_t*)0x20efeff8 = (uint64_t)0xc6;
    r[116] = syscall(__NR_recvfrom, r[1], 0x207af000ul, 0x0ul, 0x0ul,
                     0x20efefa0ul, 0x60ul);
    break;
  }
  return 0;
}

void loop()
{
  long i;
  pthread_t th[18];

  memset(r, -1, sizeof(r));
  for (i = 0; i < 9; i++) {
    pthread_create(&th[i], 0, thr, (void*)i);
    usleep(rand() % 10000);
  }
  usleep(rand() % 100000);
}

int main()
{
  setup_tun(0, true);
  loop();
  return 0;
}