net/ipv6/output_core.c

   1 /*
   2  * IPv6 library code, needed by static components when full IPv6 support is
   3  * not configured or static.  These functions are needed by GSO/GRO implementation.
   4  */
   5 #include <linux/export.h>
   6 #include <net/ipv6.h>
   7 #include <net/ip6_fib.h>
   8
   9 void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
  10 {
  11         static atomic_t ipv6_fragmentation_id;
  12         int old, new;
  13
  14 #if IS_ENABLED(CONFIG_IPV6)
  15         if (rt && !(rt->dst.flags & DST_NOPEER)) {
  16                 struct inet_peer *peer;
  17                 struct net *net;
  18
  19                 net = dev_net(rt->dst.dev);
  20                 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
  21                 if (peer) {
  22                         fhdr->identification = htonl(inet_getid(peer, 0));
  23                         inet_putpeer(peer);
  24                         return;
  25                 }
  26         }
  27 #endif
  28         do {
  29                 old = atomic_read(&ipv6_fragmentation_id);
  30                 new = old + 1;
  31                 if (!new)
  32                         new = 1;
  33         } while (atomic_cmpxchg(&ipv6_fragmentation_id, old, new) != old);
  34         fhdr->identification = htonl(new);
  35 }
  36 EXPORT_SYMBOL(ipv6_select_ident);
  37
  38 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
  39 {
  40         u16 offset = sizeof(struct ipv6hdr);
  41         struct ipv6_opt_hdr *exthdr =
  42                                 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
  43         unsigned int packet_len = skb->tail - skb->network_header;
  44         int found_rhdr = 0;
  45         *nexthdr = &ipv6_hdr(skb)->nexthdr;
  46
  47         while (offset + 1 <= packet_len) {
  48
  49                 switch (**nexthdr) {
  50
  51                 case NEXTHDR_HOP:
  52                         break;
  53                 case NEXTHDR_ROUTING:
  54                         found_rhdr = 1;
  55                         break;
  56                 case NEXTHDR_DEST:
  57 #if IS_ENABLED(CONFIG_IPV6_MIP6)
  58                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
  59                                 break;
  60 #endif
  61                         if (found_rhdr)
  62                                 return offset;
  63                         break;
  64                 default :
  65                         return offset;
  66                 }
  67
  68                 offset += ipv6_optlen(exthdr);
  69                 *nexthdr = &exthdr->nexthdr;
  70                 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
  71                                                  offset);
  72         }
  73
  74         return offset;
  75 }
  76 EXPORT_SYMBOL(ip6_find_1stfragopt);