关于IPv6的原始套接字

想利用原始套接字编写一个可以在发送UDP数据包时更改源地址的程序，v4下已经成功，但在v6下出现问题，没找到对应v4中setsockopt(sockfd, IPPROTO_IP, IP_HDRINCL, &flag, sizeof(flag)); 中IP_HDRINCL对应的套接字选项，请大家指点迷津，谢谢!

我的代码：
#define MAX_SIZE 1024
int main ( int argc, char **argv )
{
int sockfd;
struct sockaddr_in6 addr;
memset ( &addr, 0, sizeof ( struct sockaddr_in6 ) );

unsigned char buffer[ MAX_SIZE ];
memset( buffer, 0, MAX_SIZE);
int addrlen;

const int flag = 1;
if ( ( sockfd = socket ( PF_INET6, SOCK_RAW, IPPROTO_UDP ) ) < 0 )
{
fprintf ( stderr, "Create Error:%s\n", strerror ( errno ) );
exit ( 1 );
}

setsockopt(sockfd, IPPROTO_IPV6, IP_HDRINCL, &flag, sizeof(flag)); // [ ？ ]

struct ip6_hdr *ip6;
struct udphdr *udp;
int head_len = sizeof(struct ip6_hdr) + sizeof(struct udphdr);

ip6 = (struct ip6_hdr*)buffer;
if ( inet_pton ( AF_INET6, "2001:da8:1001:300::1", &ip6->ip6_src ) <= 0 )
{
fprintf ( stderr, "Address Error:%s\n", strerror ( errno ) );
exit ( 1 );
}
if ( inet_pton ( AF_INET6, "2001:da8:1001:230::1", &ip6->ip6_dst ) <= 0 )
{
fprintf ( stderr, "Address Error:%s\n", strerror ( errno ) );
exit ( 1 );
}
ip6->ip6_plen = htons(head_len);
ip6->ip6_nxt = IPPROTO_UDP;
ip6->ip6_hlim = 255 ;

udp = (struct udphdr *)(buffer + sizeof(struct ip6_hdr) );
udp->source = htons( 8888 );
udp->dest = htons( 8888 );
udp->len = htons(sizeof( struct udphdr ));
udp->check = 0;

// [ fill the address struct of the socket ]
addr.sin6_family = AF_INET6;
addr.sin6_port = htons ( 8888 );
if ( inet_pton ( AF_INET6, "2001:da8:1001:230::1", &addr.sin6_addr ) <= 0 )
{
fprintf ( stderr, "Address Error:%s\n", strerror ( errno ) );
exit ( 1 );
}
while(1)
{
addrlen = sizeof ( struct sockaddr_in6 );
sendto ( sockfd, buffer, head_len, 0, ( struct sockaddr * )&addr, addrlen );
}
close ( sockfd );
}