/* Process encapsulated map request header: lisp header and the interal IP and
* UDP header */
int
lisp_msg_ecm_decap(lbuf_t *pkt, uint16_t *src_port)
{
uint16_t ipsum = 0;
uint16_t udpsum = 0;
int udp_len = 0;
struct udphdr *udph;
struct ip *iph;
/* this is the new start of the packet */
lisp_msg_pull_ecm_hdr(pkt);
/* Set and extract inner layer 3 packet */
lbuf_reset_l3(pkt);
iph = pkt_pull_ip(pkt);
/* Set and extract inner layer 4 packet */
lbuf_reset_l4(pkt);
udph = pkt_pull_udp(pkt);
/* Set the beginning of the LISP msg*/
lbuf_reset_lisp(pkt);
/* This should overwrite the external port (dst_port in map-reply =
* inner src_port in encap map-request) */
*src_port = ntohs(udph->source);
#ifdef BSD
udp_len = ntohs(udph->uh_ulen);
#else
udp_len = ntohs(udph->len);
#endif
/* Verify the checksums. */
if (iph->ip_v == IPVERSION) {
ipsum = ip_checksum((uint16_t *) iph, sizeof(struct ip));
if (ipsum != 0) {
OOR_LOG(LDBG_2, "IP checksum failed.");
}
}
/* Verify UDP checksum only if different from 0.
* This means we ACCEPT UDP checksum 0! */
if (udph->check != 0) {
udpsum = udp_checksum(udph, udp_len, iph,
ip_version_to_sock_afi(iph->ip_v));
if (udpsum != 0) {
OOR_LOG(LDBG_2, "UDP checksum failed.");
return (BAD);
}
}
OOR_LOG(LDBG_2, "%s, inner IP: %s -> %s, inner UDP: %d -> %d",
lisp_msg_hdr_to_char(pkt),
ip_to_char(&iph->ip_src, ip_version_to_sock_afi(iph->ip_v)),
ip_to_char(&iph->ip_dst, ip_version_to_sock_afi(iph->ip_v)),
ntohs(udph->source), ntohs(udph->dest));
return (GOOD);
}
int
tun_read_and_decap_pkt(int sock, lbuf_t *b, uint32_t *iid)
{
uint8_t ttl = 0, tos = 0;
int afi;
struct udphdr *udph;
lisp_data_hdr_t *lisph;
vxlan_gpe_hdr_t *vxlanh;
int port;
if (sock_data_recv(sock, b, &afi, &ttl, &tos) != GOOD) {
return(BAD);
}
if (afi == AF_INET){
/* With input RAW UDP sockets in IPv4, we get the whole external
* IPv4 packet */
lbuf_reset_ip(b);
pkt_pull_ip(b);
lbuf_reset_udp(b);
}else{
/* With input RAW UDP sockets in IPv6, we get the whole external
* UDP packet */
lbuf_reset_udp(b);
}
udph = pkt_pull_udp(b);
/* FILTER UDP: with input RAW UDP sockets, we receive all UDP packets,
* we only want LISP data ones */
switch (ntohs(udph->dest)){
case LISP_DATA_PORT:
lisph = lisp_data_pull_hdr(b);
if (LDHDR_LSB_BIT(lisph)){
*iid = lisp_data_hdr_get_iid(lisph);
}else{
*iid = 0;
}
port = LISP_DATA_PORT;
break;
case VXLAN_GPE_DATA_PORT:
vxlanh = vxlan_gpe_data_pull_hdr(b);
if (VXLAN_HDR_VNI_BIT(vxlanh)){
*iid = vxlan_gpe_hdr_get_vni(vxlanh);
}
port = VXLAN_GPE_DATA_PORT;
break;
default:
return (ERR_NOT_ENCAP);
}
/* RESET L3: prepare for output */
lbuf_reset_l3(b);
/* UPDATE IP TOS and TTL. Checksum is also updated for IPv4
* NOTE: we always assume an IP payload*/
ip_hdr_set_ttl_and_tos(lbuf_data(b), ttl, tos);
OOR_LOG(LDBG_3, "INPUT (%d): %s",port, ip_src_and_dst_to_char(lbuf_l3(b),
"Inner IP: %s -> %s"));
return(GOOD);
}