struct udphdr *build_ip_header(
uint8_t *cur_ptr,
lisp_addr_t *src_addr,
lisp_addr_t *dst_addr,
int ip_len)
{
struct ip *iph;
struct ip6_hdr *ip6h;
struct udphdr *udph;
switch (src_addr->afi) {
case AF_INET:
ip_len = ip_len + sizeof(struct ip);
iph = (struct ip *) cur_ptr;
iph->ip_hl = 5;
iph->ip_v = IPVERSION;
iph->ip_tos = 0;
iph->ip_len = htons(ip_len);
iph->ip_id = htons(get_IP_ID());
iph->ip_off = 0; /* XXX Control packets can be fragmented */
iph->ip_ttl = 255;
iph->ip_p = IPPROTO_UDP;
iph->ip_src.s_addr = src_addr->address.ip.s_addr;
iph->ip_dst.s_addr = dst_addr->address.ip.s_addr;
iph->ip_sum = 0;
iph->ip_sum = ip_checksum((uint16_t *)cur_ptr, sizeof(struct ip));
udph = (struct udphdr *) CO(iph,sizeof(struct ip));
break;
case AF_INET6:
ip6h = (struct ip6_hdr *) cur_ptr;
ip6h->ip6_hops = 255;
ip6h->ip6_vfc = (IP6VERSION << 4);
ip6h->ip6_nxt = IPPROTO_UDP;
ip6h->ip6_plen = htons(ip_len);
memcpy(ip6h->ip6_src.s6_addr,
src_addr->address.ipv6.s6_addr,
sizeof(struct in6_addr));
memcpy(ip6h->ip6_dst.s6_addr,
dst_addr->address.ipv6.s6_addr,
sizeof(struct in6_addr));
udph = (struct udphdr *) CO(ip6h,sizeof(struct ip6_hdr));
break;
default:
lispd_log_msg(LISP_LOG_DEBUG_2,"build_ip_header: Uknown AFI of the source address: %d",src_addr->afi);
return(NULL);
}
return(udph);
}
struct ip *
pkt_push_ipv4(lbuf_t *b, struct in_addr *src, struct in_addr *dst, int proto)
{
struct ip *iph;
iph = lbuf_push_uninit(b, sizeof(struct ip));
/* XXX: assume no other headers */
iph->ip_hl = 5;
iph->ip_v = IPVERSION;
iph->ip_tos = 0;
iph->ip_len = htons(lbuf_size(b));
iph->ip_id = htons(get_IP_ID());
/* Do not fragment flag. See 5.4.1 in LISP RFC (6830)
* TODO: decide if we allow fragments in case of control */
iph->ip_off = htons(IP_DF);
iph->ip_ttl = 255;
iph->ip_p = proto;
iph->ip_src.s_addr = src->s_addr;
iph->ip_dst.s_addr = dst->s_addr;
/* FIXME: ip checksum could be offloaded to NIC*/
/* iph->ip_sum = 0; */
iph->ip_sum = ip_checksum((uint16_t *) iph, sizeof(struct ip));
return(iph);
}
