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         struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
  19
  20         if (p->locator_match.v64)
  21                 return p->csum_diff;
  22         else
  23                 return compute_csum_diff8((__be32 *)&iaddr->loc,
  24                                           (__be32 *)&p->locator);
  25 }
  26
  27 static void ila_csum_do_neutral(struct ila_addr *iaddr,
  28                                 struct ila_params *p)
  29 {
  30         __sum16 *adjust = (__force __sum16 *)&iaddr->ident.v16[3];
  31         __wsum diff, fval;
  32
  33         /* Check if checksum adjust value has been cached */
  34         if (p->locator_match.v64) {
  35                 diff = p->csum_diff;
  36         } else {
  37                 diff = compute_csum_diff8((__be32 *)&p->locator,
  38                                           (__be32 *)iaddr);
  39         }
  40
  41         fval = (__force __wsum)(ila_csum_neutral_set(iaddr->ident) ?
  42                         CSUM_NEUTRAL_FLAG : ~CSUM_NEUTRAL_FLAG);
  43
  44         diff = csum_add(diff, fval);
  45
  46         *adjust = ~csum_fold(csum_add(diff, csum_unfold(*adjust)));
  47
  48         /* Flip the csum-neutral bit. Either we are doing a SIR->ILA
  49          * translation with ILA_CSUM_NEUTRAL_MAP as the csum_method
  50          * and the C-bit is not set, or we are doing an ILA-SIR
  51          * tranlsation and the C-bit is set.
  52          */
  53         iaddr->ident.csum_neutral ^= 1;
  54 }
  55
  56 static void ila_csum_adjust_transport(struct sk_buff *skb,
  57                                       struct ila_params *p)
  58 {
  59         __wsum diff;
  60         struct ipv6hdr *ip6h = ipv6_hdr(skb);
  61         struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
  62         size_t nhoff = sizeof(struct ipv6hdr);
  63
  64         switch (ip6h->nexthdr) {
  65         case NEXTHDR_TCP:
  66                 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct tcphdr)))) {
  67                         struct tcphdr *th = (struct tcphdr *)
  68                                         (skb_network_header(skb) + nhoff);
  69
  70                         diff = get_csum_diff(ip6h, p);
  71                         inet_proto_csum_replace_by_diff(&th->check, skb,
  72                                                         diff, true);
  73                 }
  74                 break;
  75         case NEXTHDR_UDP:
  76                 if (likely(pskb_may_pull(skb, nhoff + sizeof(struct udphdr)))) {
  77                         struct udphdr *uh = (struct udphdr *)
  78                                         (skb_network_header(skb) + nhoff);
  79
  80                         if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
  81                                 diff = get_csum_diff(ip6h, p);
  82                                 inet_proto_csum_replace_by_diff(&uh->check, skb,
  83                                                                 diff, true);
  84                                 if (!uh->check)
  85                                         uh->check = CSUM_MANGLED_0;
  86                         }
  87                 }
  88                 break;
  89         case NEXTHDR_ICMP:
  90                 if (likely(pskb_may_pull(skb,
  91                                          nhoff + sizeof(struct icmp6hdr)))) {
  92                         struct icmp6hdr *ih = (struct icmp6hdr *)
  93                                         (skb_network_header(skb) + nhoff);
  94
  95                         diff = get_csum_diff(ip6h, p);
  96                         inet_proto_csum_replace_by_diff(&ih->icmp6_cksum, skb,
  97                                                         diff, true);
  98                 }
  99                 break;
 100         }
 101
 102         /* Now change destination address */
 103         iaddr->loc = p->locator;
 104 }
 105
 106 void ila_update_ipv6_locator(struct sk_buff *skb, struct ila_params *p,
 107                              bool set_csum_neutral)
 108 {
 109         struct ipv6hdr *ip6h = ipv6_hdr(skb);
 110         struct ila_addr *iaddr = ila_a2i(&ip6h->daddr);
 111
 112         /* First deal with the transport checksum */
 113         if (ila_csum_neutral_set(iaddr->ident)) {
 114                 /* C-bit is set in the locator indicating that this
 115                  * is a locator being translated to a SIR address.
 116                  * Perform (receiver) checksum-neutral translation.
 117                  */
 118                 if (!set_csum_neutral)
 119                         ila_csum_do_neutral(iaddr, p);
 120         } else {
 121                 switch (p->csum_mode) {
 122                 case ILA_CSUM_ADJUST_TRANSPORT:
 123                         ila_csum_adjust_transport(skb, p);
 124                         break;
 125                 case ILA_CSUM_NEUTRAL_MAP:
 126                         ila_csum_do_neutral(iaddr, p);
 127                         break;
 128                 case ILA_CSUM_NO_ACTION:
 129                         break;
 130                 }
 131         }
 132
 133         /* Now change destination address */
 134         iaddr->loc = p->locator;
 135 }
 136
 137 void ila_init_saved_csum(struct ila_params *p)
 138 {
 139         if (!p->locator_match.v64)
 140                 return;
 141
 142         p->csum_diff = compute_csum_diff8(
 143                                 (__be32 *)&p->locator,
 144                                 (__be32 *)&p->locator_match);
 145 }
 146
 147 static int __init ila_init(void)
 148 {
 149         int ret;
 150
 151         ret = ila_lwt_init();
 152
 153         if (ret)
 154                 goto fail_lwt;
 155
 156         ret = ila_xlat_init();
 157         if (ret)
 158                 goto fail_xlat;
 159
 160         return 0;
 161 fail_xlat:
 162         ila_lwt_fini();
 163 fail_lwt:
 164         return ret;
 165 }
 166
 167 static void __exit ila_fini(void)
 168 {
 169         ila_xlat_fini();
 170         ila_lwt_fini();
 171 }
 172
 173 module_init(ila_init);
 174 module_exit(ila_fini);
 175 MODULE_ALIAS_RTNL_LWT(ILA);
 176 MODULE_AUTHOR("Tom Herbert <tom@herbertland.com>");
 177 MODULE_LICENSE("GPL");