int
ip_hdr_set_ttl_and_tos(struct iphdr *iph, int ttl, int tos)
{
struct ip6_hdr *ip6h;
if (iph->version == 4) {
/*XXX It seems that there is a bug in uClibc that causes ttl=0 in
* OpenWRT. This is a quick workaround */
if (ttl != 0) {
iph->ttl = ttl;
}
iph->tos = tos;
/* We need to recompute the checksum since we have changed the TTL
* and TOS header fields.
*
* New checksum must be computed with the checksum header field
* with 0s */
iph->check = 0;
iph->check = ip_checksum((uint16_t*) iph, sizeof(struct iphdr));
} else if (iph->version == 6) {
ip6h = (struct ip6_hdr *) iph;
/*XXX It seems that there is a bug in uClibc that causes ttl=0 in
* OpenWRT. This is a quick workaround */
if (ttl != 0) {
/* ttl = Hops limit in IPv6 */
ip6h->ip6_hops = ttl;
}
/* tos = Traffic class field in IPv6 */
IPV6_SET_TC(ip6h, tos);
} else {
return(BAD);
}
return(GOOD);
}
void add_ip_header (
char *position,
char *original_packet_position,
int ip_payload_length,
lisp_addr_t *src_addr,
lisp_addr_t *dst_addr)
{
struct iphdr *iph = NULL;
struct iphdr *inner_iph = NULL;
struct ip6_hdr *ip6h = NULL;
struct ip6_hdr *inner_ip6h = NULL;
uint8_t tos = 0;
uint8_t ttl = 0;
inner_iph = (struct iphdr *) original_packet_position;
/* We SHOULD copy ttl and tos fields from the inner packet to the encapsulated one */
if (inner_iph->version == 4 ) {
tos = inner_iph->tos;
ttl = inner_iph->ttl;
} else {
inner_ip6h = (struct ip6_hdr *) original_packet_position;
ttl = inner_ip6h->ip6_hops; /* ttl = Hops limit in IPv6 */
//tos = (inner_ip6h->ip6_flow & 0x0ff00000) >> 20; /* 4 bits version, 8 bits Traffic Class, 20 bits flow-ID */
tos = IPV6_GET_TC(*inner_ip6h); /* tos = Traffic class field in IPv6 */
}
/*
* Construct and add the outer ip header
*/
switch (dst_addr->afi){
case AF_INET:
iph = (struct iphdr *) position;
iph->version = 4;
//iph->ihl = sizeof ( struct iphdr ) >>2;
iph->ihl = 5; /* Minimal IPv4 header */ /*XXX Beware, hardcoded. Supposing no IP options */
iph->tos = tos;
iph->tot_len = htons(ip_payload_length);
iph->frag_off = htons(IP_DF); /* Do not fragment flag. See 5.4.1 in LISP RFC (6830) */
iph->ttl = ttl;
iph->protocol = IPPROTO_UDP;
iph->check = 0; //Computed by the NIC (checksum offloading)
iph->daddr = dst_addr->address.ip.s_addr;
iph->saddr = src_addr->address.ip.s_addr;
break;
case AF_INET6:
ip6h = ( struct ip6_hdr *) position;
IPV6_SET_VERSION(ip6h, 6);
IPV6_SET_TC(ip6h,tos);
IPV6_SET_FLOW_LABEL(ip6h,0);
ip6h->ip6_plen = htons(ip_payload_length);
ip6h->ip6_nxt = IPPROTO_UDP;
ip6h->ip6_hops = ttl;
memcopy_lisp_addr(&(ip6h->ip6_dst),dst_addr);
memcopy_lisp_addr(&(ip6h->ip6_src),src_addr);
break;
default:
break;
}
}
void process_input_packet(int fd,
int afi,
int tun_receive_fd)
{
uint8_t *packet = NULL;
int length = 0;
uint8_t ttl = 0;
uint8_t tos = 0;
struct lisphdr *lisp_hdr = NULL;
struct iphdr *iph = NULL;
struct ip6_hdr *ip6h = NULL;
struct udphdr *udph = NULL;
if ((packet = (uint8_t *) malloc(MAX_IP_PACKET))==NULL){
lispd_log_msg(LISP_LOG_ERR,"process_input_packet: Couldn't allocate space for packet: %s", strerror(errno));
return;
}
memset(packet,0,MAX_IP_PACKET);
if (get_data_packet (fd,
afi,
packet,
&length,
&ttl,
&tos) == BAD){
lispd_log_msg(LISP_LOG_DEBUG_2,"process_input_packet: get_data_packet error: %s", strerror(errno));
free(packet);
return;
}
if(afi == AF_INET){
/* With input RAW UDP sockets in IPv4, we get the whole external IPv4 packet */
udph = (struct udphdr *) CO(packet,sizeof(struct iphdr));
}else{
/* With input RAW UDP sockets in IPv6, we get the whole external UDP packet */
udph = (struct udphdr *) packet;
}
/* With input RAW UDP sockets, we receive all UDP packets, we only want lisp data ones */
if(ntohs(udph->dest) != LISP_DATA_PORT){
free(packet);
//lispd_log_msg(LISP_LOG_DEBUG_3,"INPUT (No LISP data): UDP dest: %d ",ntohs(udph->dest));
return;
}
lisp_hdr = (struct lisphdr *) CO(udph,sizeof(struct udphdr));
length = length - sizeof(struct udphdr) - sizeof(struct lisphdr);
iph = (struct iphdr *) CO(lisp_hdr,sizeof(struct lisphdr));
lispd_log_msg(LISP_LOG_DEBUG_3,"INPUT (4341): Inner src: %s | Inner dst: %s ",
get_char_from_lisp_addr_t(extract_src_addr_from_packet((char *)iph)),
get_char_from_lisp_addr_t(extract_dst_addr_from_packet((char *)iph)));
if (iph->version == 4) {
if(ttl!=0){ /*XXX It seems that there is a bug in uClibc that causes ttl=0 in OpenWRT. This is a quick workaround */
iph->ttl = ttl;
}
iph->tos = tos;
/* We need to recompute the checksum since we have changed the TTL and TOS header fields */
iph->check = 0; /* New checksum must be computed with the checksum header field with 0s */
iph->check = ip_checksum((uint16_t*) iph, sizeof(struct iphdr));
}else{
ip6h = ( struct ip6_hdr *) iph;
if(ttl!=0){ /*XXX It seems that there is a bug in uClibc that causes ttl=0 in OpenWRT. This is a quick workaround */
ip6h->ip6_hops = ttl; /* ttl = Hops limit in IPv6 */
}
IPV6_SET_TC(ip6h,tos); /* tos = Traffic class field in IPv6 */
}
if ((write(tun_receive_fd, iph, length)) < 0){
lispd_log_msg(LISP_LOG_DEBUG_2,"lisp_input: write error: %s\n ", strerror(errno));
}
free(packet);
}