user: 请从给定的汇编指令推导出C源代码：

```asm
<router_advertisement>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x90,%rsp
  mov    %rdi,-0x78(%rbp)
  mov    %rsi,-0x80(%rbp)
  mov    %rdx,-0x88(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movl   $0x0,-0x68(%rbp)
  movl   $0x0,-0x64(%rbp)
  movl   $0x0,-0x60(%rbp)
  movq   $0x0,-0x50(%rbp)
  movq   $0x0,-0x48(%rbp)
  movq   $0x0,-0x40(%rbp)
  movq   $0x0,-0x38(%rbp)
  movq   $0x0,-0x30(%rbp)
  movq   $0x0,-0x28(%rbp)
  movq   $0x0,-0x20(%rbp)
  movq   $0x0,-0x18(%rbp)
  movl   $0xff,-0x50(%rbp)
  movl   $0x2,-0x4c(%rbp)
  movl   $0x1,-0x14(%rbp)
  movl   $0xfd20,-0x5c(%rbp)
  movl   $0x7530,-0x58(%rbp)
  movl   $0x3e8,-0x54(%rbp)
  addl   $0x8,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x80(%rbp),%rax
  mov    $0x10,%edx
  mov    %rax,%rsi
  mov    %rcx,%rdi
  call   <memcpy@plt>
  addl   $0x10,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  lea    -0x50(%rbp),%rax
  mov    $0x10,%edx
  mov    %rax,%rsi
  mov    %rcx,%rdi
  call   <memcpy@plt>
  addl   $0x10,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movb   $0x86,(%rax)
  addl   $0x1,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  addl   $0x1,-0x68(%rbp)
  addl   $0x2,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  addl   $0x1,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  addl   $0x1,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x5c(%rbp),%eax
  sar    $0x8,%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  movslq %eax,%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x1(%rax),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x5c(%rbp),%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x1(%rax),%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  addl   $0x2,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x58(%rbp),%eax
  shr    $0x18,%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  movslq %eax,%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x1(%rax),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x58(%rbp),%eax
  sar    $0x10,%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x1(%rax),%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x2(%rax),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x58(%rbp),%eax
  sar    $0x8,%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x2(%rax),%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x3(%rax),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x58(%rbp),%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x3(%rax),%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  addl   $0x4,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x54(%rbp),%eax
  shr    $0x18,%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  movslq %eax,%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x1(%rax),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x54(%rbp),%eax
  sar    $0x10,%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x1(%rax),%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x2(%rax),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x54(%rbp),%eax
  sar    $0x8,%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x2(%rax),%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x3(%rax),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%edx
  mov    -0x54(%rbp),%eax
  mov    %eax,%esi
  mov    -0x68(%rbp),%eax
  cltq
  lea    0x3(%rax),%rcx
  mov    -0x78(%rbp),%rax
  add    %rcx,%rax
  or     %esi,%edx
  mov    %dl,(%rax)
  addl   $0x4,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movb   $0x1,(%rax)
  addl   $0x1,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movb   $0x1,(%rax)
  addl   $0x1,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x78(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x88(%rbp),%rax
  mov    $0x6,%edx
  mov    %rax,%rsi
  mov    %rcx,%rdi
  call   <memcpy@plt>
  addl   $0x6,-0x68(%rbp)
  mov    -0x68(%rbp),%eax
  sub    $0x28,%eax
  mov    %eax,-0x60(%rbp)
  mov    -0x60(%rbp),%eax
  sar    $0x8,%eax
  mov    %eax,%edx
  mov    -0x78(%rbp),%rax
  add    $0x4,%rax
  mov    %dl,(%rax)
  mov    -0x78(%rbp),%rax
  add    $0x5,%rax
  mov    -0x60(%rbp),%edx
  mov    %dl,(%rax)
  mov    -0x68(%rbp),%edx
  mov    -0x78(%rbp),%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <checksum_icmpv6@plt>
  mov    %eax,-0x64(%rbp)
  mov    -0x64(%rbp),%eax
  sar    $0x8,%eax
  mov    %eax,%edx
  mov    -0x78(%rbp),%rax
  add    $0x2a,%rax
  mov    %dl,(%rax)
  mov    -0x78(%rbp),%rax
  add    $0x2b,%rax
  mov    -0x64(%rbp),%edx
  mov    %dl,(%rax)
  mov    -0x78(%rbp),%rax
  mov    -0x8(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L8
  call   <__stack_chk_fail@plt>
L8:
  leave
  ret
```

assistant: ```c
char *router_advertisement(char *buffer, uint8_t *IPv6_address, uint8_t *mac_address) {
  int offset = 0;
  uint16_t checksum = 0;
  uint16_t payload_length = 0;
  uint8_t dst_address[16] = {0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01};
  uint16_t router_lifetime = 64800;
  uint32_t reachable_time = 30000;
  uint32_t retrans_time = 1000;
  offset += 8;
  memcpy(&buffer[offset], &IPv6_address[0], 16);
  offset += 16;
  memcpy(&buffer[offset], &dst_address[0], 16);
  offset += 16;
  buffer[offset] = 0x86;
  offset += 1;
  buffer[offset] = 0;
  offset += 1;
  offset += 2;
  buffer[offset] = 0;
  offset += 1;
  buffer[offset] = 0;
  offset += 1;
  buffer[offset] |= (router_lifetime >> 8) & 255;
  buffer[offset + 1] |= (router_lifetime)&255;
  offset += 2;
  buffer[offset] |= (reachable_time >> 24) & 255;
  buffer[offset + 1] |= (reachable_time >> 16) & 255;
  buffer[offset + 2] |= (reachable_time >> 8) & 255;
  buffer[offset + 3] |= (reachable_time)&255;
  offset += 4;
  buffer[offset] |= (retrans_time >> 24) & 255;
  buffer[offset + 1] |= (retrans_time >> 16) & 255;
  buffer[offset + 2] |= (retrans_time >> 8) & 255;
  buffer[offset + 3] |= (retrans_time)&255;
  offset += 4;
  buffer[offset] = 0x01;
  offset += 1;
  buffer[offset] = 0x01;
  offset += 1;
  memcpy(&buffer[offset], &mac_address[0], 6);
  offset += 6;
  payload_length = (offset - 40);
  buffer[4] = (payload_length >> 8) & 255;
  buffer[5] = (payload_length >> 0) & 255;
  checksum = checksum_icmpv6(buffer, (offset));
  buffer[42] = (checksum >> 8) & 255;
  buffer[43] = (checksum >> 0) & 255;
  return buffer;
}
```