user: 这段汇编代码用C语言表示是什么样的:

```asm
<pseudo_header_initial>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x30,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    -0x28(%rbp),%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%eax
  sar    $0x4,%eax
  and    $0xf,%eax
  mov    %eax,-0xc(%rbp)
  movl   $0x0,-0x1c(%rbp)
  movl   $0x0,-0x18(%rbp)
  cmpl   $0x4,-0xc(%rbp)
  jne    L18
  mov    -0x28(%rbp),%rax
  add    $0x24,%rax
  mov    (%rax),%eax
  mov    %eax,-0x1c(%rbp)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%eax
  and    $0xf,%eax
  shl    $0x2,%eax
  mov    %eax,-0x18(%rbp)
  jmp    L124
L18:
  cmpl   $0x6,-0xc(%rbp)
  jne    L137
  mov    -0x28(%rbp),%rax
  add    $0x18,%rax
  mov    (%rax),%eax
  mov    %eax,-0x1c(%rbp)
  movl   $0x28,-0x18(%rbp)
  jmp    L124
L137:
  mov    $0xffff0001,%eax
  jmp    L107
L124:
  cmpl   $0x6,-0x1c(%rbp)
  je     L54
  cmpl   $0x11,-0x1c(%rbp)
  jne    L24
L54:
  movl   $0x0,-0x14(%rbp)
  mov    -0x18(%rbp),%eax
  cltq
  sub    %rax,-0x30(%rbp)
  cmpl   $0x4,-0xc(%rbp)
  jne    L69
  mov    -0x18(%rbp),%ecx
  mov    -0x28(%rbp),%rax
  mov    $0x0,%edx
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <cksum_generic@plt>
  test   %rax,%rax
  je     L139
  mov    $0xffff0002,%eax
  jmp    L107
L139:
  mov    -0x30(%rbp),%rax
  movzwl %ax,%eax
  mov    %rax,%rdi
  call   <htons@plt>
  mov    %eax,%edx
  mov    -0x1c(%rbp),%eax
  shl    $0x8,%eax
  add    %eax,%edx
  mov    -0x8(%rbp),%rax
  add    $0x18,%rax
  mov    (%rax),%eax
  add    %eax,%edx
  mov    -0x8(%rbp),%rax
  add    $0x1c,%rax
  mov    (%rax),%eax
  add    %eax,%edx
  mov    -0x8(%rbp),%rax
  add    $0x20,%rax
  mov    (%rax),%eax
  add    %eax,%edx
  mov    -0x8(%rbp),%rax
  add    $0x24,%rax
  mov    (%rax),%eax
  add    %edx,%eax
  mov    %eax,-0x14(%rbp)
  jmp    L27
L69:
  mov    -0x8(%rbp),%rax
  add    $0x8,%rax
  mov    (%rax),%edx
  mov    -0x1c(%rbp),%eax
  shl    $0x8,%eax
  add    %edx,%eax
  mov    %eax,-0x14(%rbp)
  movl   $0x4,-0x10(%rbp)
  jmp    L117
L23:
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%edx
  mov    -0x10(%rbp),%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,4),%rcx
  mov    -0x8(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%eax
  add    %eax,%edx
  mov    -0x10(%rbp),%eax
  cltq
  add    $0x2,%rax
  lea    0x0(,%rax,4),%rcx
  mov    -0x8(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%eax
  add    %eax,%edx
  mov    -0x10(%rbp),%eax
  cltq
  add    $0x3,%rax
  lea    0x0(,%rax,4),%rcx
  mov    -0x8(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%eax
  add    %edx,%eax
  add    %eax,-0x14(%rbp)
  addl   $0x4,-0x10(%rbp)
L117:
  cmpl   $0x13,-0x10(%rbp)
  jle    L23
L27:
  mov    -0x14(%rbp),%eax
  shr    $0x10,%eax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  movzwl %ax,%eax
  add    %edx,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x14(%rbp),%eax
  shr    $0x10,%eax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  movzwl %ax,%eax
  add    %edx,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x14(%rbp),%eax
  mov    %eax,%edi
  call   <ntohs@plt>
  jmp    L107
L24:
  mov    $0xffff0001,%eax
L107:
  leave
  ret
```

assistant: ```c
uint32_t pseudo_header_initial(const int8_t *buf, size_t len) {
  const uint16_t const *hwbuf = (const uint16_t *)buf;
  int8_t ipv = (buf[0] & 0xF0) >> 4;
  int8_t proto = 0;
  int headersize = 0;
  if (ipv == 4) {
    proto = buf[9];
    headersize = (buf[0] & 0x0F) * 4;
  } else if (ipv == 6) {
    proto = buf[6];
    headersize = 40;
  } else {
    return 0xFFFF0001;
  }
  if (proto == 6 || proto == 17) {
    uint32_t sum = 0;
    len -= headersize;
    if (ipv == 4) {
      if (cksum_generic((unsigned char *)buf, headersize, 0) != 0) {
        return 0xFFFF0002;
      }
      sum = htons(len & 0x0000FFFF) + (proto << 8) + hwbuf[6] + hwbuf[7] + hwbuf[8] + hwbuf[9];
    } else {
      sum = hwbuf[2] + (proto << 8);
      int i;
      for (i = 4; i < 20; i += 4) {
        sum += hwbuf[i] + hwbuf[i + 1] + hwbuf[i + 2] + hwbuf[i + 3];
      }
    }
    sum = ((sum & 0xffff0000) >> 16) + (sum & 0xffff);
    sum = ((sum & 0xffff0000) >> 16) + (sum & 0xffff);
    return ntohs(sum);
  }
  return 0xFFFF0001;
}
```