+ const u32 fragment_first = ip4_get_fragment_offset_bytes (ip0);
+ const u32 fragment_length =
+ clib_net_to_host_u16 (ip0->length) - ip4_header_bytes (ip0);
+ const u32 fragment_last = fragment_first + fragment_length - 1;
+ if (fragment_first > fragment_last || fragment_first + fragment_length > UINT16_MAX - 20 || (fragment_length < 8 && ip4_get_fragment_more (ip0))) // 8 is minimum frag length per RFC 791
+ {
+ next0 = IP4_REASSEMBLY_NEXT_DROP;
+ error0 = IP4_ERROR_REASS_MALFORMED_PACKET;
+ }
+ else
+ {
+ ip4_reass_key_t k;
+ k.as_u64[0] =
+ (u64) vnet_buffer (b0)->sw_if_index[VLIB_RX] |
+ (u64) ip0->src_address.as_u32 << 32;
+ k.as_u64[1] =
+ (u64) ip0->dst_address.as_u32 |
+ (u64) ip0->fragment_id << 32 | (u64) ip0->protocol << 48;
+
+ ip4_reass_t *reass =
+ ip4_reass_find_or_create (vm, rm, rt, &k,
+ &vec_drop_timeout);
+
+ if (reass)
+ {
+ switch (ip4_reass_update
+ (vm, node, rm, rt, reass, &bi0, &next0, &error0,
+ &vec_drop_overlap, &vec_drop_compress,
+ is_feature))
+ {
+ case IP4_REASS_RC_OK:
+ /* nothing to do here */
+ break;
+ case IP4_REASS_RC_INTERNAL_ERROR:
+ /* drop everything and start with a clean slate */
+ ip4_reass_on_timeout (vm, rm, reass,
+ &vec_drop_internal_error);
+ ip4_reass_free (rm, rt, reass);
+ goto next_packet;
+ break;
+ }
+ }
+ else
+ {
+ next0 = IP4_REASSEMBLY_NEXT_DROP;
+ error0 = IP4_ERROR_REASS_LIMIT_REACHED;
+ }
+ }