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 #include <net/secure_seq.h>
  10
  11 void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
  12 {
  13         static atomic_t ipv6_fragmentation_id;
  14         struct in6_addr addr;
  15         int old, new;
  16
  17 #if IS_ENABLED(CONFIG_IPV6)
  18         struct inet_peer *peer;
  19         struct net *net;
  20
  21         net = dev_net(rt->dst.dev);
  22         peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
  23         if (peer) {
  24                 fhdr->identification = htonl(inet_getid(peer, 0));
  25                 inet_putpeer(peer);
  26                 return;
  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
  36         addr = rt->rt6i_dst.addr;
  37         addr.s6_addr32[0] ^= (__force __be32)new;
  38         fhdr->identification = htonl(secure_ipv6_id(addr.s6_addr32));
  39 }
  40 EXPORT_SYMBOL(ipv6_select_ident);
  41
  42 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
  43 {
  44         u16 offset = sizeof(struct ipv6hdr);
  45         struct ipv6_opt_hdr *exthdr =
  46                                 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
  47         unsigned int packet_len = skb_tail_pointer(skb) -
  48                 skb_network_header(skb);
  49         int found_rhdr = 0;
  50         *nexthdr = &ipv6_hdr(skb)->nexthdr;
  51
  52         while (offset + 1 <= packet_len) {
  53
  54                 switch (**nexthdr) {
  55
  56                 case NEXTHDR_HOP:
  57                         break;
  58                 case NEXTHDR_ROUTING:
  59                         found_rhdr = 1;
  60                         break;
  61                 case NEXTHDR_DEST:
  62 #if IS_ENABLED(CONFIG_IPV6_MIP6)
  63                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
  64                                 break;
  65 #endif
  66                         if (found_rhdr)
  67                                 return offset;
  68                         break;
  69                 default :
  70                         return offset;
  71                 }
  72
  73                 offset += ipv6_optlen(exthdr);
  74                 *nexthdr = &exthdr->nexthdr;
  75                 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
  76                                                  offset);
  77         }
  78
  79         return offset;
  80 }
  81 EXPORT_SYMBOL(ip6_find_1stfragopt);
  82
  83 #if IS_ENABLED(CONFIG_IPV6)
  84 int ip6_dst_hoplimit(struct dst_entry *dst)
  85 {
  86         int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
  87         if (hoplimit == 0) {
  88                 struct net_device *dev = dst->dev;
  89                 struct inet6_dev *idev;
  90
  91                 rcu_read_lock();
  92                 idev = __in6_dev_get(dev);
  93                 if (idev)
  94                         hoplimit = idev->cnf.hop_limit;
  95                 else
  96                         hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
  97                 rcu_read_unlock();
  98         }
  99         return hoplimit;
 100 }
 101 EXPORT_SYMBOL(ip6_dst_hoplimit);
 102 #endif
 103
 104 int __ip6_local_out(struct sk_buff *skb)
 105 {
 106         int len;
 107
 108         len = skb->len - sizeof(struct ipv6hdr);
 109         if (len > IPV6_MAXPLEN)
 110                 len = 0;
 111         ipv6_hdr(skb)->payload_len = htons(len);
 112
 113         return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
 114                        skb_dst(skb)->dev, dst_output);
 115 }
 116 EXPORT_SYMBOL_GPL(__ip6_local_out);
 117
 118 int ip6_local_out(struct sk_buff *skb)
 119 {
 120         int err;
 121
 122         err = __ip6_local_out(skb);
 123         if (likely(err == 1))
 124                 err = dst_output(skb);
 125
 126         return err;
 127 }
 128 EXPORT_SYMBOL_GPL(ip6_local_out);