ila_common.c
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#include <linux/errno.h>
#include <linux/ip.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/types.h>
#include <net/checksum.h>
#include <net/ip.h>
#include <net/ip6_fib.h>
#include <net/lwtunnel.h>
#include <net/protocol.h>
#include <uapi/linux/ila.h>
#include "ila.h"
static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
{
struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
if (p->locator_match.v64)
return p->csum_diff;
else
return compute_csum_diff8((__be32 *)&iaddr->loc,
(__be32 *)&p->locator);
}
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 *)&p->locator,
(__be32 *)iaddr);
}
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);
switch (ip6h->nexthdr) {
case NEXTHDR_TCP:
if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
struct tcphdr *th = (struct tcphdr *)
(skb_network_header(skb) + nhoff);
diff = get_csum_diff(ip6h, p);
inet_proto_csum_replace_by_diff(&th->check, skb,
diff, true);
}
break;
case NEXTHDR_UDP:
if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
struct udphdr *uh = (struct udphdr *)
(skb_network_header(skb) + nhoff);
if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
diff = get_csum_diff(ip6h, p);
inet_proto_csum_replace_by_diff(&uh->check, skb,
diff, true);
if (!uh->check)
uh->check = CSUM_MANGLED_0;
}
}
break;
case NEXTHDR_ICMP:
if (likely(pskb_may_pull(skb,
nhoff + sizeof(struct icmp6hdr)))) {
struct icmp6hdr *ih = (struct icmp6hdr *)
(skb_network_header(skb) + nhoff);
diff = get_csum_diff(ip6h, p);
inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
diff, true);
}
break;
}
/* Now change destination address */
iaddr->loc = p->locator;
}
void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
bool set_csum_neutral)
{
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.
*/
if (!set_csum_neutral)
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,
(__be32 *)&p->locator_match);
}
static int __init ila_init(void)
{
int ret;
ret = ila_lwt_init();
if (ret)
goto fail_lwt;
ret = ila_xlat_init();
if (ret)
goto fail_xlat;
return 0;
fail_xlat:
ila_lwt_fini();
fail_lwt:
return ret;
}
static void __exit ila_fini(void)
{
ila_xlat_fini();
ila_lwt_fini();
}
module_init(ila_init);
module_exit(ila_fini);
MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");
MODULE_LICENSE("GPL");