diff options
Diffstat (limited to 'vnet/vnet/map/ip4_map.c')
| -rw-r--r-- | vnet/vnet/map/ip4_map.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/vnet/vnet/map/ip4_map.c b/vnet/vnet/map/ip4_map.c index 6ed176c8e60..c8ee2764f23 100644 --- a/vnet/vnet/map/ip4_map.c +++ b/vnet/vnet/map/ip4_map.c @@ -156,6 +156,28 @@ ip4_map_ip6_lookup_bypass (vlib_buffer_t *p0, ip4_header_t *ip) } /* + * ip4_map_ttl + */ +static inline void +ip4_map_decrement_ttl (ip4_header_t *ip, u8 *error) +{ + i32 ttl = ip->ttl; + + /* Input node should have reject packets with ttl 0. */ + ASSERT (ip->ttl > 0); + + u32 checksum = ip->checksum + clib_host_to_net_u16(0x0100); + checksum += checksum >= 0xffff; + ip->checksum = checksum; + ttl -= 1; + ip->ttl = ttl; + *error = ttl <= 0 ? IP4_ERROR_TIME_EXPIRED : *error; + + /* Verify checksum. */ + ASSERT (ip->checksum == ip4_header_checksum(ip)); +} + +/* * ip4_map */ static uword @@ -345,6 +367,9 @@ ip4_map (vlib_main_t *vm, */ port0 = ip4_map_port_and_security_check(d0, ip40, &next0, &error0); + /* Decrement IPv4 TTL */ + ip4_map_decrement_ttl(ip40, &error0); + /* MAP calc */ u32 da40 = clib_net_to_host_u32(ip40->dst_address.as_u32); u16 dp40 = clib_net_to_host_u16(port0); |