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ila: add checksum neutral ILA translations

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Support checksum neutral ILA as described in the ILA draft. The low
order 16 bits of the identifier are used to contain the checksum
adjustment value.

The csum-mode parameter is added to described checksum processing. There
are three values:
 - adjust transport checksum (previous behavior)
 - do checksum neutral mapping
 - do nothing

On output the csum-mode in the ila_params is checked and acted on. If
mode is checksum neutral mapping then to mapping and set C-bit.

On input, C-bit is checked. If it is set checksum-netural mapping is
done (regardless of csum-mode in ila params) and C-bit will be cleared.
If it is not set then action in csum-mode is taken.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert
2016-04-23 11:46:57 -07:00
committed by David S. Miller
parent 642c2c9558
commit 90bfe662db
5 changed files with 112 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
net/ipv6/ila/ila_common.c
View File

@@ -17,21 +17,50 @@ static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
{
struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
if (iaddr->loc.v64 == p->locator_match.v64)
if (p->locator_match.v64)
return p->csum_diff;
else
return compute_csum_diff8((__be32 *)&iaddr->loc,
(__be32 *)&p->locator);
}
void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
static void ila_csum_do_neutral(struct ila_addr *iaddr,
struct ila_params *p)
{
__sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
__wsum diff, fval;
/* Check if checksum adjust value has been cached */
if (p->locator_match.v64) {
diff = p->csum_diff;
} else {
diff = compute_csum_diff8((__be32 *)iaddr,
(__be32 *)&p->locator);
}
fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
~CSUM_NEUTRAL_FLAG : CSUM_NEUTRAL_FLAG);
diff = csum_add(diff, fval);
*adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
/* Flip the csum-neutral bit. Either we are doing a SIR->ILA
* translation with ILA_CSUM_NEUTRAL_MAP as the csum_method
* and the C-bit is not set, or we are doing an ILA-SIR
* tranlsation and the C-bit is set.
*/
iaddr->ident.csum_neutral ^= 1;
}
static void ila_csum_adjust_transport(struct sk_buff *skb,
struct ila_params *p)
{
__wsum diff;
struct ipv6hdr *ip6h = ipv6_hdr(skb);
struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
size_t nhoff = sizeof(struct ipv6hdr);
/* First update checksum */
switch (ip6h->nexthdr) {
case NEXTHDR_TCP:
if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
@@ -74,6 +103,45 @@ void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
iaddr->loc = p->locator;
}
void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
{
struct ipv6hdr *ip6h = ipv6_hdr(skb);
struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
/* First deal with the transport checksum */
if (ila_csum_neutral_set(iaddr->ident)) {
/* C-bit is set in the locator indicating that this
* is a locator being translated to a SIR address.
* Perform (receiver) checksum-neutral translation.
*/
ila_csum_do_neutral(iaddr, p);
} else {
switch (p->csum_mode) {
case ILA_CSUM_ADJUST_TRANSPORT:
ila_csum_adjust_transport(skb, p);
break;
case ILA_CSUM_NEUTRAL_MAP:
ila_csum_do_neutral(iaddr, p);
break;
case ILA_CSUM_NO_ACTION:
break;
}
}
/* Now change destination address */
iaddr->loc = p->locator;
}
void ila_init_saved_csum(struct ila_params *p)
{
if (!p->locator_match.v64)
return;
p->csum_diff = compute_csum_diff8(
(__be32 *)&p->locator_match,
(__be32 *)&p->locator);
}
static int __init ila_init(void)
{
int ret;