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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)
{
if (*(__be64 *)&ip6h->daddr == p->locator_match)
return p->csum_diff;
else
return compute_csum_diff8((__be32 *)&ip6h->daddr,
(__be32 *)&p->locator);
}
void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
{
__wsum diff;
struct ipv6hdr *ip6h = ipv6_hdr(skb);
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)))) {
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 */
*(__be64 *)&ip6h->daddr = p->locator;
}
static int __init ila_init(void)
{
int ret;
ret = ila_lwt_init();
if (ret)
goto fail_lwt;
fail_lwt:
return ret;
}
static void __exit ila_fini(void)
{
ila_lwt_fini();
}
module_init(ila_init);
module_exit(ila_fini);
MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");
MODULE_LICENSE("GPL");
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