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#include "lib/tunnel_encaps.h"
static
int decode_encap(const void *p, size_t sub_tlv_len, void *encap, size_t *encap_size, u16 *flags)
{
if (sub_tlv_len > *encap_size) {
log(L_TRACE "WG: encapsulation len error %d > %d", sub_tlv_len, *encap_size);
return -1;
}
memcpy(encap, p, sub_tlv_len);
*encap_size = sub_tlv_len;
*flags |= FLAG_BGP_TUNNEL_ENCAP_A_SUB_TLV_ENCAP;
return 0;
}
static
int decode_color(const void *p, size_t sub_tlv_len, u32 *color, u16 *flags)
{
if (sub_tlv_len != 8) {
log(L_TRACE "WG: color len error %d", sub_tlv_len);
return -1;
}
if (get_u16(p) != 0x030b) {
log(L_TRACE "WG: color error %04x", get_u16(p));
return -1;
}
*color = get_u32(p+2);
*flags |= FLAG_BGP_TUNNEL_ENCAP_A_SUB_TLV_COLOR;
return 0;
}
static
int decode_udp_dest_port(const void *p, size_t sub_tlv_len, u16 *udp_dest_port, u16 *flags)
{
if (sub_tlv_len != 2) {
log(L_TRACE "WG: udp dest port len error %d", sub_tlv_len);
return -1;
}
*udp_dest_port = get_u16(p);
*flags |= FLAG_BGP_TUNNEL_ENCAP_A_SUB_TLV_UDP_DEST_PORT;
return 0;
}
static
int decode_tunnel_ep(const void *p, size_t sub_tlv_len, u32 *as4, ip_addr *tunnel_ep, u16 *flags)
{
if (sub_tlv_len < 6) {
log(L_TRACE "WG: tunnel ep len error");
return -1;
}
*as4 = get_u32(p);
u16 af = get_u16(p + 4);
switch (af) {
case NET_IP4:
if (sub_tlv_len != 10) {
log(L_TRACE "WG: IPv4 len error %d", sub_tlv_len);
return -1;
}
*tunnel_ep = ipa_from_ip4(get_ip4(p + 6));
*flags |= FLAG_BGP_TUNNEL_ENCAP_A_SUB_TLV_TUNNEL_EP;
return 0;
case NET_IP6:
if (sub_tlv_len != 22) {
log(L_TRACE "WG: IPv6 len error %d", sub_tlv_len);
return -1;
}
*tunnel_ep = ipa_from_ip6(get_ip6(p + 6));
*flags |= FLAG_BGP_TUNNEL_ENCAP_A_SUB_TLV_TUNNEL_EP;
return 0;
default:
log(L_TRACE "WG: Address family error %d", af);
return -1;
}
}
static
int decode_sub_tlv(const u8 *p, size_t len, void *encap, size_t *encap_size,
u32 *tunnel_ep_as, ip_addr *tunnel_ep_addr,
u32 *color, u16 *udp_dest_port, u16 *flags)
{
if (len < 3) {
log(L_TRACE "WG: sub_tlv len error %d", len);
return -1;
}
const u8 *first = p;
const u8 *last = p + len;
int type = get_u8(p++);
u16 sub_tlv_len = 0;
log(L_TRACE "WG: sub tlv type %d", type);
if (type >= 0 && type <= 127) {
sub_tlv_len = get_u8(p);
p++;
} else if (type >= 128 && type <= 255) {
sub_tlv_len = get_u16(p);
p += 2;
} else {
log(L_TRACE "WG: sub_tlv type error %d", type);
return -1;
}
log(L_TRACE "WG: sub tlv len %d", sub_tlv_len);
if (p + sub_tlv_len > last) {
log(L_TRACE "WG: sub_tlv value len error %d", sub_tlv_len);
return -1;
}
int res = 0;
switch (type) {
case BGP_TUNNEL_ENCAP_A_SUB_TLV_ENCAP:
res = decode_encap(p, sub_tlv_len, encap, encap_size, flags);
break;
case BGP_TUNNEL_ENCAP_A_SUB_TLV_TUNNEL_EP:
res = decode_tunnel_ep(p, sub_tlv_len, tunnel_ep_as, tunnel_ep_addr, flags);
break;
case BGP_TUNNEL_ENCAP_A_SUB_TLV_COLOR:
res = decode_color(p, sub_tlv_len, color, flags);
break;
case BGP_TUNNEL_ENCAP_A_SUB_TLV_UDP_DEST_PORT:
res = decode_udp_dest_port(p, sub_tlv_len, udp_dest_port, flags);
break;
default:
/* Skip unsupported sub-TLV. */
res = 0;
break;
}
if (res < 0)
return res;
return p - first + sub_tlv_len;
}
int decode_tunnel_encap(const eattr *e, u16 wg_tunnel_type, void *encap, size_t *encap_size, u32 *as4, ip_addr *tunnel_ep, u32 *color, u16 *udp_port, u16 *flags)
{
const u8 *p = e->u.ptr->data;
int len = e->u.ptr->length;
if (len < 4) {
log(L_TRACE "WG: tunnel_encap len error %d", len);
return -1;
}
u16 tunnel_type = get_u16(p);
log(L_DEBUG "WG: tunnel type %d", tunnel_type);
if (tunnel_type != wg_tunnel_type) {
log(L_TRACE "WG: tunnel type error %d", tunnel_type);
return -1;
}
u16 value_length = get_u16(p + 2);
log(L_TRACE "WG: tunnel encap value len %d", value_length);
if (len < value_length + 4) {
log(L_TRACE "WG: tunnel encap len error %d", value_length);
return -1;
}
for (const u8 *cur = p + 4; cur < p + 4 + value_length;) {
int res = decode_sub_tlv(cur, value_length, encap, encap_size, as4, tunnel_ep, color, udp_port, flags);
if (res < 0) {
log(L_TRACE "WG: decode error %d", res);
return res;
}
cur += res;
}
return 0;
}
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