lib/csum.h

   1 /*
   2  * Copyright (c) 2008, 2011, 2015 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef CSUM_H
  18 #define CSUM_H 1
  19
  20 #include <stddef.h>
  21 #include <stdint.h>
  22 #include "openvswitch/types.h"
  23
  24 struct in6_addr;
  25
  26 ovs_be16 csum(const void *, size_t);
  27 uint32_t csum_continue(uint32_t partial, const void *, size_t);
  28 ovs_be16 csum_finish(uint32_t partial);
  29 ovs_be16 recalc_csum16(ovs_be16 old_csum, ovs_be16 old_u16, ovs_be16 new_u16);
  30 ovs_be16 recalc_csum32(ovs_be16 old_csum, ovs_be32 old_u32, ovs_be32 new_u32);
  31 ovs_be16 recalc_csum48(ovs_be16 old_csum, const struct eth_addr old_mac,
  32                        const struct eth_addr new_mac);
  33 ovs_be16 recalc_csum128(ovs_be16 old_csum, ovs_16aligned_be32 old_u32[4],
  34                         const struct in6_addr *);
  35
  36 #ifndef __CHECKER__
  37 /* Adds the 16 bits in 'new' to the partial IP checksum 'partial' and returns
  38  * the updated checksum.  (To start a new checksum, pass 0 for 'partial'.  To
  39  * obtain the finished checksum, pass the return value to csum_finish().) */
  40 static inline uint32_t
  41 csum_add16(uint32_t partial, ovs_be16 new)
  42 {
  43     return partial + new;
  44 }
  45
  46 /* Adds the 32 bits in 'new' to the partial IP checksum 'partial' and returns
  47  * the updated checksum.  (To start a new checksum, pass 0 for 'partial'.  To
  48  * obtain the finished checksum, pass the return value to csum_finish().) */
  49 static inline uint32_t
  50 csum_add32(uint32_t partial, ovs_be32 new)
  51 {
  52     return partial + (new >> 16) + (new & 0xffff);
  53 }
  54 #else
  55 uint32_t csum_add16(uint32_t partial, ovs_be16);
  56 uint32_t csum_add32(uint32_t partial, ovs_be32);
  57 #endif
  58
  59 #endif /* csum.h */