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net: Generalize checksum_init functions 

Create a general __skb_checksum_validate function (actually a
macro) to subsume the various checksum_init functions. This
function can either init the checksum, or do the full validation
(logically checksum_init+skb_check_complete)-- a flag specifies
if full vaidation is performed. Also, there is a flag to the function
to indicate that zero checksums are allowed (to support optional
UDP checksums).

Added several stub functions for calling __skb_checksum_validate.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2014-05-02 16:29:18 -07:00 committed by David S. Miller
parent 20fce54fa7
commit 76ba0aae67
1 changed files with 93 additions and 0 deletions
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93
include/linux/skbuff.h
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@ -2741,6 +2741,99 @@ static inline __sum16 skb_checksum_complete(struct sk_buff *skb)
0 : __skb_checksum_complete(skb);
}
/* Check if we need to perform checksum complete validation.
*
* Returns true if checksum complete is needed, false otherwise
* (either checksum is unnecessary or zero checksum is allowed).
*/
static inline bool __skb_checksum_validate_needed(struct sk_buff *skb,
bool zero_okay,
__sum16 check)
{
if (skb_csum_unnecessary(skb)) {
return false;
} else if (zero_okay && !check) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
return false;
}
return true;
}
/* For small packets <= CHECKSUM_BREAK peform checksum complete directly
* in checksum_init.
*/
#define CHECKSUM_BREAK 76
/* Validate (init) checksum based on checksum complete.
*
* Return values:
* 0: checksum is validated or try to in skb_checksum_complete. In the latter
* case the ip_summed will not be CHECKSUM_UNNECESSARY and the pseudo
* checksum is stored in skb->csum for use in __skb_checksum_complete
* non-zero: value of invalid checksum
*
*/
static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb,
bool complete,
__wsum psum)
{
if (skb->ip_summed == CHECKSUM_COMPLETE) {
if (!csum_fold(csum_add(psum, skb->csum))) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
return 0;
}
}
skb->csum = psum;
if (complete || skb->len <= CHECKSUM_BREAK)
return __skb_checksum_complete(skb);
return 0;
}
static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto)
{
return 0;
}
/* Perform checksum validate (init). Note that this is a macro since we only
* want to calculate the pseudo header which is an input function if necessary.
* First we try to validate without any computation (checksum unnecessary) and
* then calculate based on checksum complete calling the function to compute
* pseudo header.
*
* Return values:
* 0: checksum is validated or try to in skb_checksum_complete
* non-zero: value of invalid checksum
*/
#define __skb_checksum_validate(skb, proto, complete, \
zero_okay, check, compute_pseudo) \
({ \
__sum16 __ret = 0; \
if (__skb_checksum_validate_needed(skb, zero_okay, check)) \
__ret = __skb_checksum_validate_complete(skb, \
complete, compute_pseudo(skb, proto)); \
__ret; \
})
#define skb_checksum_init(skb, proto, compute_pseudo) \
__skb_checksum_validate(skb, proto, false, false, 0, compute_pseudo)
#define skb_checksum_init_zero_check(skb, proto, check, compute_pseudo) \
__skb_checksum_validate(skb, proto, false, true, check, compute_pseudo)
#define skb_checksum_validate(skb, proto, compute_pseudo) \
__skb_checksum_validate(skb, proto, true, false, 0, compute_pseudo)
#define skb_checksum_validate_zero_check(skb, proto, check, \
compute_pseudo) \
__skb_checksum_validate_(skb, proto, true, true, check, compute_pseudo)
#define skb_checksum_simple_validate(skb) \
__skb_checksum_validate(skb, 0, true, false, 0, null_compute_pseudo)
#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
void nf_conntrack_destroy(struct nf_conntrack *nfct);
static inline void nf_conntrack_put(struct nf_conntrack *nfct)