/*
* Construct an IGMP message in the output packet buffer. The caller may
* have already placed data in that buffer, of length 'datalen'.
*/
void buildIgmp(uint32_t src, uint32_t dst, int type, int code, uint32_t group, int datalen) {
struct ip *ip;
struct igmp *igmp;
extern int curttl;
ip = (struct ip *)send_buf;
ip->ip_src.s_addr = src;
ip->ip_dst.s_addr = dst;
ip_set_len(ip, IP_HEADER_RAOPT_LEN + IGMP_MINLEN + datalen);
if (IN_MULTICAST(ntohl(dst))) {
ip->ip_ttl = curttl;
} else {
ip->ip_ttl = MAXTTL;
}
/* Add Router Alert option */
((u_char*)send_buf+MIN_IP_HEADER_LEN)[0] = IPOPT_RA;
((u_char*)send_buf+MIN_IP_HEADER_LEN)[1] = 0x04;
((u_char*)send_buf+MIN_IP_HEADER_LEN)[2] = 0x00;
((u_char*)send_buf+MIN_IP_HEADER_LEN)[3] = 0x00;
igmp = (struct igmp *)(send_buf + IP_HEADER_RAOPT_LEN);
igmp->igmp_type = type;
igmp->igmp_code = code;
igmp->igmp_group.s_addr = group;
igmp->igmp_cksum = 0;
igmp->igmp_cksum = inetChksum((u_short *)igmp,
IP_HEADER_RAOPT_LEN + datalen);
}
/*
* Construct an IGMP message in the output packet buffer. The caller may
* have already placed data in that buffer, of length 'datalen'.
*/
void buildIgmp(uint32 src, uint32 dst, int type, int code, uint32 group, int datalen) {
struct ip *ip;
struct igmp *igmp;
extern int curttl;
ip = (struct ip *)send_buf;
ip->ip_src.s_addr = src;
ip->ip_dst.s_addr = dst;
ip->ip_len = MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen;
ip->ip_len = htons(ip->ip_len);
if (IN_MULTICAST(ntohl(dst))) {
ip->ip_ttl = curttl;
} else {
ip->ip_ttl = MAXTTL;
}
igmp = (struct igmp *)(send_buf + MIN_IP_HEADER_LEN);
igmp->igmp_type = type;
igmp->igmp_code = code;
igmp->igmp_group.s_addr = group;
igmp->igmp_cksum = 0;
igmp->igmp_cksum = inetChksum((u_short *)igmp,
IGMP_MINLEN + datalen);
}