user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<connect_nb>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x60,%rsp
  mov    %edi,-0x44(%rbp)
  mov    %rsi,-0x50(%rbp)
  mov    %edx,-0x48(%rbp)
  mov    %ecx,-0x54(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movl   $0x1,-0x38(%rbp)
  mov    D34(%rip),%rax
  mov    (%rax),%edx
  mov    D60(%rip),%rax
  mov    (%rax),%esi
  lea    -0x38(%rbp),%rcx
  mov    -0x44(%rbp),%eax
  mov    $0x4,%r8d
  mov    %eax,%edi
  call   <setsockopt@plt>
  test   %rax,%rax
  jns    L120
  mov    $0xffffffff,%eax
  jmp    L98
L120:
  mov    D122(%rip),%rax
  mov    (%rax),%ecx
  mov    -0x44(%rbp),%eax
  mov    $0x0,%edx
  mov    %ecx,%esi
  mov    %eax,%edi
  call   <fcntl@plt>
  mov    %eax,-0x38(%rbp)
  mov    -0x38(%rbp),%edx
  mov    D91(%rip),%rax
  mov    (%rax),%eax
  or     %eax,%edx
  mov    D90(%rip),%rax
  mov    (%rax),%ecx
  mov    -0x44(%rbp),%eax
  mov    %ecx,%esi
  mov    %eax,%edi
  call   <fcntl@plt>
  mov    -0x48(%rbp),%edx
  mov    -0x50(%rbp),%rcx
  mov    -0x44(%rbp),%eax
  mov    %rcx,%rsi
  mov    %eax,%edi
  call   <connect@plt>
  mov    %eax,-0x24(%rbp)
  cmpl   $0x0,-0x24(%rbp)
  jns    L97
  mov    D135(%rip),%rax
  mov    (%rax),%edx
  mov    D103(%rip),%rax
  mov    (%rax),%eax
  cmp    %eax,%edx
  je     L97
  mov    $0xffffffff,%eax
  jmp    L98
L97:
  cmpl   $0x0,-0x24(%rbp)
  je     L34
  lea    -0x2c(%rbp),%rax
  mov    %rax,%rdi
  call   <FD_ZERO@plt>
  lea    -0x2c(%rbp),%rdx
  mov    -0x44(%rbp),%eax
  mov    %rdx,%rsi
  mov    %eax,%edi
  call   <FD_SET@plt>
  lea    -0x28(%rbp),%rax
  mov    %rax,%rdi
  call   <FD_ZERO@plt>
  lea    -0x28(%rbp),%rdx
  mov    -0x44(%rbp),%eax
  mov    %rdx,%rsi
  mov    %eax,%edi
  call   <FD_SET@plt>
  mov    -0x54(%rbp),%eax
  mov    %eax,-0x20(%rbp)
  movq   $0x0,-0x18(%rbp)
  mov    -0x44(%rbp),%eax
  lea    0x1(%rax),%edi
  lea    -0x20(%rbp),%rcx
  lea    -0x28(%rbp),%rdx
  lea    -0x2c(%rbp),%rax
  mov    %rcx,%r8
  mov    $0x0,%ecx
  mov    %rax,%rsi
  call   <select@plt>
  test   %rax,%rax
  jne    L52
  mov    D62(%rip),%rax
  mov    (%rax),%edx
  mov    D135(%rip),%rax
  mov    %edx,(%rax)
  mov    $0xffffffff,%eax
  jmp    L98
L52:
  lea    -0x2c(%rbp),%rdx
  mov    -0x44(%rbp),%eax
  mov    %rdx,%rsi
  mov    %eax,%edi
  call   <FD_ISSET@plt>
  test   %rax,%rax
  jne    L48
  lea    -0x28(%rbp),%rdx
  mov    -0x44(%rbp),%eax
  mov    %rdx,%rsi
  mov    %eax,%edi
  call   <FD_ISSET@plt>
  test   %rax,%rax
  je     L34
L48:
  movl   $0x4,-0x30(%rbp)
  mov    D16(%rip),%rax
  mov    (%rax),%edx
  mov    D60(%rip),%rax
  mov    (%rax),%esi
  lea    -0x30(%rbp),%rdi
  lea    -0x34(%rbp),%rcx
  mov    -0x44(%rbp),%eax
  mov    %rdi,%r8
  mov    %eax,%edi
  call   <getsockopt@plt>
  test   %rax,%rax
  jns    L14
  mov    -0x44(%rbp),%eax
  mov    %eax,%edi
  call   <close@plt>
  mov    $0xffffffff,%eax
  jmp    L98
L14:
  mov    -0x34(%rbp),%eax
  test   %eax,%eax
  je     L151
  mov    -0x44(%rbp),%eax
  mov    %eax,%edi
  call   <close@plt>
  mov    -0x34(%rbp),%edx
  mov    D135(%rip),%rax
  mov    %edx,(%rax)
  mov    $0xffffffff,%eax
  jmp    L98
L151:
  mov    -0x38(%rbp),%edx
  mov    D90(%rip),%rax
  mov    (%rax),%ecx
  mov    -0x44(%rbp),%eax
  mov    %ecx,%esi
  mov    %eax,%edi
  call   <fcntl@plt>
  mov    $0x0,%eax
  jmp    L98
L34:
  mov    D67(%rip),%rax
  mov    (%rax),%edx
  mov    D135(%rip),%rax
  mov    %edx,(%rax)
  mov    $0xffffffff,%eax
L98:
  mov    -0x8(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L46
  call   <__stack_chk_fail@plt>
L46:
  leave
  ret
```

assistant: ```c
int connect_nb(int fd, struct sockaddr *dest, socklen_t len, int timeout) {
  int ret, flags = 1, err;
  unsigned l;
  fd_set rfds, wfds;
  struct timeval tv;
  if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (void *)&flags, sizeof(flags)) < 0)
    return -1;
  flags = fcntl(fd, F_GETFL, 0);
  fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  ret = connect(fd, dest, len);
  if ((ret < 0) && (errno != EINPROGRESS))
    return -1;
  if (ret != 0) {
    FD_ZERO(&rfds);
    FD_SET(fd, &rfds);
    FD_ZERO(&wfds);
    FD_SET(fd, &wfds);
    tv.tv_sec = timeout;
    tv.tv_usec = 0;
    if (select(fd + 1, &rfds, &wfds, NULL, &tv) == 0) {
      errno = ETIMEDOUT;
      return -1;
    }
    if (FD_ISSET(fd, &rfds) || FD_ISSET(fd, &wfds)) {
      l = sizeof(err);
      if (getsockopt(fd, SOL_SOCKET, SO_ERROR, (void *)&err, &l) < 0) {
        close(fd);
        return -1;
      }
      if (err != 0) {
        close(fd);
        errno = err;
        return -1;
      }
      fcntl(fd, F_SETFL, flags);
      return 0;
    }
  }
  errno = EIO;
  return -1;
}
```