[ovs-dev] [sparse 14/18] csum: Annotate byte order to match actual usage.

[Ethan Jackson]

Looks Good.

Ethan

On Fri, May 6, 2011 at 13:16, Ben Pfaff <blp at nicira.com> wrote:
> The IP checksum algorithm yields identical results regardless of whether
> arithmetic little-endian or big-endian, but in practice OVS only passes in
> big-endian data, so it seems reasonable to annotate these functions that
> way.
> ---
>  lib/csum.c |   22 +++++++++++-----------
>  lib/csum.h |   15 ++++++++-------
>  2 files changed, 19 insertions(+), 18 deletions(-)
>
> diff --git a/lib/csum.c b/lib/csum.c
> index 33ec28b..668d710 100644
> --- a/lib/csum.c
> +++ b/lib/csum.c
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2008, 2009, 2010 Nicira Networks.
> + * Copyright (c) 2008, 2009, 2010, 2011 Nicira Networks.
>  *
>  * Licensed under the Apache License, Version 2.0 (the "License");
>  * you may not use this file except in compliance with the License.
> @@ -24,7 +24,7 @@
>  * consists of a packet in network byte order, then the return value is a value
>  * in network byte order, and if 'data' consists of a data structure in host
>  * byte order, then the return value is in host byte order. */
> -uint16_t
> +ovs_be16
>  csum(const void *data, size_t n)
>  {
>     return csum_finish(csum_continue(0, data, n));
> @@ -34,7 +34,7 @@ csum(const void *data, size_t n)
>  * the updated checksum.  (To start a new checksum, pass 0 for 'partial'.  To
>  * obtain the finished checksum, pass the return value to csum_finish().) */
>  uint32_t
> -csum_add16(uint32_t partial, uint16_t new)
> +csum_add16(uint32_t partial, ovs_be16 new)
>  {
>     return partial + new;
>  }
> @@ -43,7 +43,7 @@ csum_add16(uint32_t partial, uint16_t new)
>  * the updated checksum.  (To start a new checksum, pass 0 for 'partial'.  To
>  * obtain the finished checksum, pass the return value to csum_finish().) */
>  uint32_t
> -csum_add32(uint32_t partial, uint32_t new)
> +csum_add32(uint32_t partial, ovs_be32 new)
>  {
>     return partial + (new >> 16) + (new & 0xffff);
>  }
> @@ -56,10 +56,10 @@ csum_add32(uint32_t partial, uint32_t new)
>  uint32_t
>  csum_continue(uint32_t partial, const void *data_, size_t n)
>  {
> -    const uint16_t *data = data_;
> +    const ovs_be16 *data = data_;
>
>     for (; n > 1; n -= 2, data++) {
> -        partial = csum_add16(partial, get_unaligned_u16(data));
> +        partial = csum_add16(partial, get_unaligned_be16(data));
>     }
>     if (n) {
>         partial += *(uint8_t *) data;
> @@ -74,7 +74,7 @@ csum_continue(uint32_t partial, const void *data_, size_t n)
>  * if the data consist of a packet in network byte order, then the return value
>  * is a value in network byte order, and if the data are a data structure in
>  * host byte order, then the return value is in host byte order. */
> -uint16_t
> +ovs_be16
>  csum_finish(uint32_t partial)
>  {
>     while (partial >> 16) {
> @@ -86,8 +86,8 @@ csum_finish(uint32_t partial)
>  /* Returns the new checksum for a packet in which the checksum field previously
>  * contained 'old_csum' and in which a field that contained 'old_u16' was
>  * changed to contain 'new_u16'. */
> -uint16_t
> -recalc_csum16(uint16_t old_csum, uint16_t old_u16, uint16_t new_u16)
> +ovs_be16
> +recalc_csum16(ovs_be16 old_csum, ovs_be16 old_u16, ovs_be16 new_u16)
>  {
>     /* Ones-complement arithmetic is endian-independent, so this code does not
>      * use htons() or ntohs().
> @@ -103,8 +103,8 @@ recalc_csum16(uint16_t old_csum, uint16_t old_u16, uint16_t new_u16)
>  /* Returns the new checksum for a packet in which the checksum field previously
>  * contained 'old_csum' and in which a field that contained 'old_u32' was
>  * changed to contain 'new_u32'. */
> -uint16_t
> -recalc_csum32(uint16_t old_csum, uint32_t old_u32, uint32_t new_u32)
> +ovs_be16
> +recalc_csum32(ovs_be16 old_csum, ovs_be32 old_u32, ovs_be32 new_u32)
>  {
>     return recalc_csum16(recalc_csum16(old_csum, old_u32, new_u32),
>                          old_u32 >> 16, new_u32 >> 16);
> diff --git a/lib/csum.h b/lib/csum.h
> index 5213055..e5f35e9 100644
> --- a/lib/csum.h
> +++ b/lib/csum.h
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2008 Nicira Networks.
> + * Copyright (c) 2008, 2011 Nicira Networks.
>  *
>  * Licensed under the Apache License, Version 2.0 (the "License");
>  * you may not use this file except in compliance with the License.
> @@ -19,13 +19,14 @@
>
>  #include <stddef.h>
>  #include <stdint.h>
> +#include "openvswitch/types.h"
>
> -uint16_t csum(const void *, size_t);
> -uint32_t csum_add16(uint32_t partial, uint16_t);
> -uint32_t csum_add32(uint32_t partial, uint32_t);
> +ovs_be16 csum(const void *, size_t);
> +uint32_t csum_add16(uint32_t partial, ovs_be16);
> +uint32_t csum_add32(uint32_t partial, ovs_be32);
>  uint32_t csum_continue(uint32_t partial, const void *, size_t);
> -uint16_t csum_finish(uint32_t partial);
> -uint16_t recalc_csum16(uint16_t old_csum, uint16_t old_u16, uint16_t new_u16);
> -uint16_t recalc_csum32(uint16_t old_csum, uint32_t old_u32, uint32_t new_u32);
> +ovs_be16 csum_finish(uint32_t partial);
> +ovs_be16 recalc_csum16(ovs_be16 old_csum, ovs_be16 old_u16, ovs_be16 new_u16);
> +ovs_be16 recalc_csum32(ovs_be16 old_csum, ovs_be32 old_u32, ovs_be32 new_u32);
>
>  #endif /* csum.h */
> --
> 1.7.4.4
>
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