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 #include <net/addrconf.h>
   9
  10 void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
  11 {
  12         static atomic_t ipv6_fragmentation_id;
  13         int old, new;
  14
  15 #if IS_ENABLED(CONFIG_IPV6)
  16         if (rt && !(rt->dst.flags & DST_NOPEER)) {
  17                 struct inet_peer *peer;
  18                 struct net *net;
  19
  20                 net = dev_net(rt->dst.dev);
  21                 peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
  22                 if (peer) {
  23                         fhdr->identification = htonl(inet_getid(peer, 0));
  24                         inet_putpeer(peer);
  25                         return;
  26                 }
  27         }
  28 #endif
  29         do {
  30                 old = atomic_read(&ipv6_fragmentation_id);
  31                 new = old + 1;
  32                 if (!new)
  33                         new = 1;
  34         } while (atomic_cmpxchg(&ipv6_fragmentation_id, old, new) != old);
  35         fhdr->identification = htonl(new);
  36 }
  37 EXPORT_SYMBOL(ipv6_select_ident);
  38
  39 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
  40 {
  41         u16 offset = sizeof(struct ipv6hdr);
  42         struct ipv6_opt_hdr *exthdr =
  43                                 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
  44         unsigned int packet_len = skb_tail_pointer(skb) -
  45                 skb_network_header(skb);
  46         int found_rhdr = 0;
  47         *nexthdr = &ipv6_hdr(skb)->nexthdr;
  48
  49         while (offset + 1 <= packet_len) {
  50
  51                 switch (**nexthdr) {
  52
  53                 case NEXTHDR_HOP:
  54                         break;
  55                 case NEXTHDR_ROUTING:
  56                         found_rhdr = 1;
  57                         break;
  58                 case NEXTHDR_DEST:
  59 #if IS_ENABLED(CONFIG_IPV6_MIP6)
  60                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
  61                                 break;
  62 #endif
  63                         if (found_rhdr)
  64                                 return offset;
  65                         break;
  66                 default :
  67                         return offset;
  68                 }
  69
  70                 offset += ipv6_optlen(exthdr);
  71                 *nexthdr = &exthdr->nexthdr;
  72                 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
  73                                                  offset);
  74         }
  75
  76         return offset;
  77 }
  78 EXPORT_SYMBOL(ip6_find_1stfragopt);
  79
  80 #if IS_ENABLED(CONFIG_IPV6)
  81 int ip6_dst_hoplimit(struct dst_entry *dst)
  82 {
  83         int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
  84         if (hoplimit == 0) {
  85                 struct net_device *dev = dst->dev;
  86                 struct inet6_dev *idev;
  87
  88                 rcu_read_lock();
  89                 idev = __in6_dev_get(dev);
  90                 if (idev)
  91                         hoplimit = idev->cnf.hop_limit;
  92                 else
  93                         hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
  94                 rcu_read_unlock();
  95         }
  96         return hoplimit;
  97 }
  98 EXPORT_SYMBOL(ip6_dst_hoplimit);
  99 #endif
 100
 101 int __ip6_local_out(struct sk_buff *skb)
 102 {
 103         int len;
 104
 105         len = skb->len - sizeof(struct ipv6hdr);
 106         if (len > IPV6_MAXPLEN)
 107                 len = 0;
 108         ipv6_hdr(skb)->payload_len = htons(len);
 109
 110         return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
 111                        skb_dst(skb)->dev, dst_output);
 112 }
 113 EXPORT_SYMBOL_GPL(__ip6_local_out);
 114
 115 int ip6_local_out(struct sk_buff *skb)
 116 {
 117         int err;
 118
 119         err = __ip6_local_out(skb);
 120         if (likely(err == 1))
 121                 err = dst_output(skb);
 122
 123         return err;
 124 }
 125 EXPORT_SYMBOL_GPL(ip6_local_out);