user: 下面的汇编指令对应的C源代码是什么:

```asm
<request_mac>:
  endbr64
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x68,%rsp
  mov    %edi,%ebp
  mov    %rdx,%rbx
  mov    %ecx,0xc(%rsp)
  mov    %fs:0x28,%rax
  mov    %rax,0x58(%rsp)
  xor    %eax,%eax
  movl   $0xffffffff,0x52(%rsp)
  movw   $0xffff,0x56(%rsp)
  lea    0x10(%rsp),%r12
  mov    %r12,%rdi
  call   <set_ifr_name@plt>
  movq   $0x0,0x20(%rsp)
  movq   $0x0,0x28(%rsp)
  movq   $0x0,0x30(%rsp)
  movq   $0x0,0x38(%rsp)
  movq   $0x0,0x40(%rsp)
  mov    D46(%rip),%rax
  mov    (%rax),%eax
  mov    %eax,0x3c(%rsp)
  mov    %r12,%rsi
  mov    %ebp,%edi
  call   <get_ifr_ifindex@plt>
  mov    %eax,0x38(%rsp)
  mov    D29(%rip),%r13
  mov    0x0(%r13),%eax
  mov    %eax,0x20(%rsp)
  mov    D6(%rip),%rax
  mov    (%rax),%edi
  call   <htons@plt>
  mov    %rax,0x30(%rsp)
  lea    0x52(%rsp),%rsi
  mov    0x0(%r13),%edx
  mov    0x28(%rsp),%rdi
  mov    $0x0,%eax
  call   <memcpy@plt>
  mov    D18(%rip),%rax
  mov    (%rax),%edi
  call   <htons@plt>
  mov    %rax,0x38(%rbx)
  mov    D28(%rip),%rax
  mov    (%rax),%edi
  call   <htons@plt>
  mov    %rax,0x30(%rbx)
  mov    0x0(%r13),%eax
  mov    %eax,(%rbx)
  movl   $0x4,0x4(%rbx)
  mov    D35(%rip),%rax
  mov    (%rax),%edi
  call   <htons@plt>
  mov    %rax,0x28(%rbx)
  lea    0x20(%rbx),%rdi
  mov    $0x4,%edx
  mov    $0x0,%esi
  call   <memset@plt>
  lea    0xc(%rsp),%rsi
  lea    0x8(%rbx),%rdi
  mov    $0x8,%edx
  mov    $0x0,%eax
  call   <memcpy@plt>
  mov    %r12,%rsi
  mov    %ebp,%edi
  call   <get_ifr_hwaddr@plt>
  lea    0x10(%rbx),%rdi
  mov    $0x8,%edx
  mov    0x18(%rsp),%rsi
  mov    $0x0,%eax
  call   <memcpy@plt>
  mov    %r12,%rsi
  mov    %ebp,%edi
  call   <get_ifr_addr@plt>
  mov    0x10(%rsp),%rax
  lea    0x2(%rax),%rsi
  lea    0x18(%rbx),%rdi
  mov    $0x8,%edx
  mov    $0x0,%eax
  call   <memcpy@plt>
  mov    $0x28,%r9d
  lea    0x20(%rsp),%r8
  mov    $0x0,%ecx
  mov    $0x40,%edx
  mov    %rbx,%rsi
  mov    %ebp,%edi
  call   <sendto@plt>
  cmp    $0xffffffff,%eax
  je     L40
L67:
  mov    $0x0,%ecx
  mov    $0x40,%edx
  mov    %rbx,%rsi
  mov    %ebp,%edi
  call   <recv@plt>
  cmp    $0xffffffff,%eax
  je     L15
  test   %eax,%eax
  je     L67
L33:
  mov    0x18(%rbx),%rdx
  mov    0xc(%rdx),%eax
  shl    $0x18,%eax
  mov    0x8(%rdx),%ecx
  shl    $0x10,%ecx
  or     %ecx,%eax
  or     (%rdx),%eax
  mov    0x4(%rdx),%edx
  shl    $0x8,%edx
  or     %edx,%eax
  cmp    %eax,0xc(%rsp)
  jne    L67
  mov    0x58(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L57
  add    $0x68,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  ret
L40:
  mov    D78(%rip),%rax
  mov    (%rax),%edi
  call   <strerror@plt>
  mov    %eax,%edi
  call   <die@plt>
  jmp    L67
L15:
  mov    D78(%rip),%rax
  mov    (%rax),%edi
  call   <strerror@plt>
  mov    %eax,%edi
  call   <die@plt>
  jmp    L33
L57:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void request_mac(int fd, const char *if_name, struct ether_arp *req, uint32_t ip_addr) {
  const unsigned char ether_broadcast_addr[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
  struct ifreq ifr;
  set_ifr_name(&ifr, if_name);
  struct sockaddr_ll addr = {0};
  addr.sll_family = AF_PACKET;
  addr.sll_ifindex = get_ifr_ifindex(fd, &ifr);
  addr.sll_halen = ETHER_ADDR_LEN;
  addr.sll_protocol = htons(ETH_P_ARP);
  memcpy(addr.sll_addr, ether_broadcast_addr, ETHER_ADDR_LEN);
  req->arp_hrd = htons(ARPHRD_ETHER);
  req->arp_pro = htons(ETH_P_IP);
  req->arp_hln = ETHER_ADDR_LEN;
  req->arp_pln = sizeof(in_addr_t);
  req->arp_op = htons(ARPOP_REQUEST);
  memset(&req->arp_tha, 0, sizeof(req->arp_tha));
  memcpy(&req->arp_tpa, &ip_addr, sizeof(req->arp_tpa));
  get_ifr_hwaddr(fd, &ifr);
  memcpy(&req->arp_sha, (unsigned char *)ifr.ifr_hwaddr.sa_data, sizeof(req->arp_sha));
  get_ifr_addr(fd, &ifr);
  memcpy(&req->arp_spa, (unsigned char *)ifr.ifr_addr.sa_data + 2, sizeof(req->arp_spa));
  if (sendto(fd, req, sizeof(struct ether_arp), 0, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
    die(strerror(errno));
  }
  while (1) {
    int len = recv(fd, req, sizeof(struct ether_arp), 0);
    if (len == -1) {
      die(strerror(errno));
    }
    if (len == 0) {
      continue;
    }
    unsigned int from_addr = (req->arp_spa[3] << 24) | (req->arp_spa[2] << 16) | (req->arp_spa[1] << 8) | (req->arp_spa[0] << 0);
    if (from_addr != ip_addr) {
      continue;
    }
    break;
  }
}
```