net/ipv6/ila/ila_common.c

   1 #include <linux/errno.h>
   2 #include <linux/ip.h>
   3 #include <linux/kernel.h>
   4 #include <linux/module.h>
   5 #include <linux/skbuff.h>
   6 #include <linux/socket.h>
   7 #include <linux/types.h>
   8 #include <net/checksum.h>
   9 #include <net/ip.h>
  10 #include <net/ip6_fib.h>
  11 #include <net/lwtunnel.h>
  12 #include <net/protocol.h>
  13 #include <uapi/linux/ila.h>
  14 #include "ila.h"
  15
  16 static __wsum get_csum_diff(struct ipv6hdr *ip6h, struct ila_params *p)
  17 {
  18         if (*(__be64 *)&ip6h->daddr == p->locator_match)
  19                 return p->csum_diff;
  20         else
  21                 return compute_csum_diff8((__be32 *)&ip6h->daddr,
  22                                           (__be32 *)&p->locator);
  23 }
  24
  25 void update_ipv6_locator(struct sk_buff *skb, struct ila_params *p)
  26 {
  27         __wsum diff;
  28         struct ipv6hdr *ip6h = ipv6_hdr(skb);
  29         size_t nhoff = sizeof(struct ipv6hdr);
  30
  31         /* First update checksum */
  32         switch (ip6h->nexthdr) {
  33         case NEXTHDR_TCP:
  34                 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
  35                         struct tcphdr *th = (struct tcphdr *)
  36                                         (skb_network_header(skb) + nhoff);
  37
  38                         diff = get_csum_diff(ip6h, p);
  39                         inet_proto_csum_replace_by_diff(&th->check, skb,
  40                                                         diff, true);
  41                 }
  42                 break;
  43         case NEXTHDR_UDP:
  44                 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
  45                         struct udphdr *uh = (struct udphdr *)
  46                                         (skb_network_header(skb) + nhoff);
  47
  48                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
  49                                 diff = get_csum_diff(ip6h, p);
  50                                 inet_proto_csum_replace_by_diff(&uh->check, skb,
  51                                                                 diff, true);
  52                                 if (!uh->check)
  53                                         uh->check = CSUM_MANGLED_0;
  54                         }
  55                 }
  56                 break;
  57         case NEXTHDR_ICMP:
  58                 if (likely(pskb_may_pull(skb,
  59                                          nhoff + sizeof(struct icmp6hdr)))) {
  60                         struct icmp6hdr *ih = (struct icmp6hdr *)
  61                                         (skb_network_header(skb) + nhoff);
  62
  63                         diff = get_csum_diff(ip6h, p);
  64                         inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
  65                                                         diff, true);
  66                 }
  67                 break;
  68         }
  69
  70         /* Now change destination address */
  71         *(__be64 *)&ip6h->daddr = p->locator;
  72 }
  73
  74 static int __init ila_init(void)
  75 {
  76         int ret;
  77
  78         ret = ila_lwt_init();
  79
  80         if (ret)
  81                 goto fail_lwt;
  82
  83         ret = ila_xlat_init();
  84         if (ret)
  85                 goto fail_xlat;
  86
  87         return 0;
  88 fail_xlat:
  89         ila_lwt_fini();
  90 fail_lwt:
  91         return ret;
  92 }
  93
  94 static void __exit ila_fini(void)
  95 {
  96         ila_xlat_fini();
  97         ila_lwt_fini();
  98 }
  99
 100 module_init(ila_init);
 101 module_exit(ila_fini);
 102 MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");
 103 MODULE_LICENSE("GPL");