user: 请将以下的汇编代码转换成C语言代码:

```asm
<build_packet>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x48,%rsp
  mov    %rdi,-0x38(%rbp)
  mov    %esi,-0x3c(%rbp)
  mov    %rdx,-0x48(%rbp)
  mov    -0x38(%rbp),%rax
  mov    %rax,-0x28(%rbp)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%rax
  add    $0x4,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%rax
  add    $0x8,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%rax
  add    $0xc,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%rax
  add    $0x10,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%rax
  add    $0x14,%rax
  movl   $0x2,(%rax)
  mov    -0x28(%rbp),%rax
  mov    0x8(%rax),%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    0x8(%rax),%rax
  add    $0x4,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    0x8(%rax),%rax
  add    $0x8,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    0x8(%rax),%rax
  add    $0xc,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    0x8(%rax),%rax
  add    $0x10,%rax
  movl   $0x0,(%rax)
  mov    -0x28(%rbp),%rax
  mov    0x8(%rax),%rax
  add    $0x14,%rax
  movl   $0x1,(%rax)
  mov    -0x28(%rbp),%rax
  movw   $0x8,0x10(%rax)
  mov    -0x38(%rbp),%rax
  add    $0x18,%rax
  mov    %rax,-0x20(%rbp)
  mov    -0x20(%rbp),%rax
  movl   $0x4,(%rax)
  mov    -0x20(%rbp),%rax
  movl   $0x5,0x4(%rax)
  mov    -0x20(%rbp),%rax
  movq   $0x0,0x40(%rax)
  mov    -0x3c(%rbp),%eax
  sub    $0x18,%eax
  movzwl %ax,%eax
  shl    $0x8,%eax
  mov    %eax,%edx
  mov    -0x3c(%rbp),%eax
  sub    $0x18,%eax
  shr    $0x8,%ax
  or     %edx,%eax
  mov    %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    %dx,0x8(%rax)
  mov    -0x20(%rbp),%rax
  movq   $0x0,0x38(%rax)
  mov    -0x20(%rbp),%rax
  movq   $0x0,0x30(%rax)
  mov    -0x20(%rbp),%rax
  movl   $0x20,0xc(%rax)
  mov    -0x20(%rbp),%rax
  movl   $0x11,0x10(%rax)
  mov    -0x20(%rbp),%rax
  movq   $0x100000a,0x18(%rax)
  mov    -0x48(%rbp),%rax
  mov    %rax,%rdi
  call   <myrand@plt>
  cltq
  shl    $0x18,%rax
  and    $0xff000000,%eax
  mov    %rax,%rbx
  mov    -0x48(%rbp),%rax
  mov    %rax,%rdi
  call   <myrand@plt>
  cltq
  shl    $0x8,%rax
  and    $0xff0000,%eax
  or     %rax,%rbx
  mov    -0x48(%rbp),%rax
  mov    %rax,%rdi
  call   <myrand@plt>
  cltq
  shr    $0x8,%rax
  and    $0xff00,%eax
  or     %rax,%rbx
  mov    -0x48(%rbp),%rax
  mov    %rax,%rdi
  call   <myrand@plt>
  cltq
  shr    $0x18,%rax
  movzbl %al,%eax
  or     %rax,%rbx
  mov    %rbx,%rdx
  mov    -0x20(%rbp),%rax
  mov    %rdx,0x20(%rax)
  mov    -0x20(%rbp),%rax
  movq   $0x0,0x28(%rax)
  mov    -0x20(%rbp),%rax
  mov    0x4(%rax),%edx
  mov    -0x20(%rbp),%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <ip_fast_csum@plt>
  mov    -0x20(%rbp),%rdx
  mov    %rax,0x28(%rdx)
  mov    -0x20(%rbp),%rax
  add    $0x48,%rax
  mov    %rax,-0x18(%rbp)
  mov    -0x48(%rbp),%rax
  mov    %rax,%rdi
  call   <myrand@plt>
  mov    %eax,-0x2c(%rbp)
  mov    -0x2c(%rbp),%eax
  movzwl %ax,%eax
  shl    $0x8,%eax
  mov    %eax,%edx
  mov    -0x2c(%rbp),%eax
  shr    $0x8,%ax
  or     %edx,%eax
  mov    %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    %dx,(%rax)
  mov    -0x2c(%rbp),%eax
  sar    $0x10,%eax
  movzwl %ax,%eax
  shl    $0x8,%eax
  mov    %eax,%edx
  mov    -0x2c(%rbp),%eax
  sar    $0x10,%eax
  shr    $0x8,%ax
  or     %edx,%eax
  mov    %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    %dx,0x2(%rax)
  mov    -0x3c(%rbp),%eax
  sub    $0x60,%eax
  movzwl %ax,%eax
  shl    $0x8,%eax
  mov    %eax,%edx
  mov    -0x3c(%rbp),%eax
  sub    $0x60,%eax
  shr    $0x8,%ax
  or     %edx,%eax
  mov    %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    %dx,0x4(%rax)
  mov    -0x18(%rbp),%rax
  movq   $0x0,0x8(%rax)
  nop
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

assistant: ```c
void build_packet(char *buf, int size, uint64_t *seed) {
  struct ethhdr *eth;
  struct iphdr *ip;
  struct udphdr *udp;
  uint32_t rand_val;
  eth = (struct ethhdr *)buf;
  eth->h_dest[0] = 0x00;
  eth->h_dest[1] = 0x00;
  eth->h_dest[2] = 0x00;
  eth->h_dest[3] = 0x00;
  eth->h_dest[4] = 0x00;
  eth->h_dest[5] = 0x02;
  eth->h_source[0] = 0x00;
  eth->h_source[1] = 0x00;
  eth->h_source[2] = 0x00;
  eth->h_source[3] = 0x00;
  eth->h_source[4] = 0x00;
  eth->h_source[5] = 0x01;
  eth->h_proto = (((((unsigned short)(0x0800) & 0xFF)) << 8) | (((unsigned short)(0x0800) & 0xFF00) >> 8));
  ip = (struct iphdr *)(buf + sizeof(*eth));
  ip->version = 4;
  ip->ihl = 5;
  ip->tos = 0;
  ip->tot_len = (((((unsigned short)(size - sizeof(*eth)) & 0xFF)) << 8) | (((unsigned short)(size - sizeof(*eth)) & 0xFF00) >> 8));
  ip->id = 0;
  ip->frag_off = 0;
  ip->ttl = 32;
  ip->protocol = 17;
  ip->saddr = (((((unsigned long)(0x0A000001) & 0xFF)) << 24) | ((((unsigned long)(0x0A000001) & 0xFF00)) << 8) | ((((unsigned long)(0x0A000001) & 0xFF0000)) >> 8) | ((((unsigned long)(0x0A000001) & 0xFF000000)) >> 24));
  ip->daddr = (((((unsigned long)(myrand(seed)) & 0xFF)) << 24) | ((((unsigned long)(myrand(seed)) & 0xFF00)) << 8) | ((((unsigned long)(myrand(seed)) & 0xFF0000)) >> 8) | ((((unsigned long)(myrand(seed)) & 0xFF000000)) >> 24));
  ip->check = 0;
  ip->check = ip_fast_csum(ip, ip->ihl);
  udp = (struct udphdr *)((char *)ip + sizeof(*ip));
  rand_val = myrand(seed);
  udp->source = (((((unsigned short)(rand_val & 0xFFFF) & 0xFF)) << 8) | (((unsigned short)(rand_val & 0xFFFF) & 0xFF00) >> 8));
  udp->dest = (((((unsigned short)((rand_val >> 16) & 0xFFFF) & 0xFF)) << 8) | (((unsigned short)((rand_val >> 16) & 0xFFFF) & 0xFF00) >> 8));
  udp->len = (((((unsigned short)(size - sizeof(*eth) - sizeof(*ip)) & 0xFF)) << 8) | (((unsigned short)(size - sizeof(*eth) - sizeof(*ip)) & 0xFF00) >> 8));
  udp->check = 0;
}
```