include/net/netfilter/nf_queue.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _NF_QUEUE_H
   3 #define _NF_QUEUE_H
   4
   5 #include <linux/ip.h>
   6 #include <linux/ipv6.h>
   7 #include <linux/jhash.h>
   8
   9 /* Each queued (to userspace) skbuff has one of these. */
  10 struct nf_queue_entry {
  11         struct list_head        list;
  12         struct sk_buff          *skb;
  13         unsigned int            id;
  14         unsigned int            hook_index;     /* index in hook_entries->hook[] */
  15
  16         struct nf_hook_state    state;
  17         u16                     size; /* sizeof(entry) + saved route keys */
  18
  19         /* extra space to store route keys */
  20 };
  21
  22 #define nf_queue_entry_reroute(x) ((void *)x + sizeof(struct nf_queue_entry))
  23
  24 /* Packet queuing */
  25 struct nf_queue_handler {
  26         int             (*outfn)(struct nf_queue_entry *entry,
  27                                  unsigned int queuenum);
  28         unsigned int    (*nf_hook_drop)(struct net *net);
  29 };
  30
  31 void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh);
  32 void nf_unregister_queue_handler(struct net *net);
  33 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict);
  34
  35 void nf_queue_entry_get_refs(struct nf_queue_entry *entry);
  36 void nf_queue_entry_release_refs(struct nf_queue_entry *entry);
  37
  38 static inline void init_hashrandom(u32 *jhash_initval)
  39 {
  40         while (*jhash_initval == 0)
  41                 *jhash_initval = prandom_u32();
  42 }
  43
  44 static inline u32 hash_v4(const struct iphdr *iph, u32 initval)
  45 {
  46         /* packets in either direction go into same queue */
  47         if ((__force u32)iph->saddr < (__force u32)iph->daddr)
  48                 return jhash_3words((__force u32)iph->saddr,
  49                         (__force u32)iph->daddr, iph->protocol, initval);
  50
  51         return jhash_3words((__force u32)iph->daddr,
  52                         (__force u32)iph->saddr, iph->protocol, initval);
  53 }
  54
  55 static inline u32 hash_v6(const struct ipv6hdr *ip6h, u32 initval)
  56 {
  57         u32 a, b, c;
  58
  59         if ((__force u32)ip6h->saddr.s6_addr32[3] <
  60             (__force u32)ip6h->daddr.s6_addr32[3]) {
  61                 a = (__force u32) ip6h->saddr.s6_addr32[3];
  62                 b = (__force u32) ip6h->daddr.s6_addr32[3];
  63         } else {
  64                 b = (__force u32) ip6h->saddr.s6_addr32[3];
  65                 a = (__force u32) ip6h->daddr.s6_addr32[3];
  66         }
  67
  68         if ((__force u32)ip6h->saddr.s6_addr32[1] <
  69             (__force u32)ip6h->daddr.s6_addr32[1])
  70                 c = (__force u32) ip6h->saddr.s6_addr32[1];
  71         else
  72                 c = (__force u32) ip6h->daddr.s6_addr32[1];
  73
  74         return jhash_3words(a, b, c, initval);
  75 }
  76
  77 static inline u32 hash_bridge(const struct sk_buff *skb, u32 initval)
  78 {
  79         struct ipv6hdr *ip6h, _ip6h;
  80         struct iphdr *iph, _iph;
  81
  82         switch (eth_hdr(skb)->h_proto) {
  83         case htons(ETH_P_IP):
  84                 iph = skb_header_pointer(skb, skb_network_offset(skb),
  85                                          sizeof(*iph), &_iph);
  86                 if (iph)
  87                         return hash_v4(iph, initval);
  88                 break;
  89         case htons(ETH_P_IPV6):
  90                 ip6h = skb_header_pointer(skb, skb_network_offset(skb),
  91                                           sizeof(*ip6h), &_ip6h);
  92                 if (ip6h)
  93                         return hash_v6(ip6h, initval);
  94                 break;
  95         }
  96
  97         return 0;
  98 }
  99
 100 static inline u32
 101 nfqueue_hash(const struct sk_buff *skb, u16 queue, u16 queues_total, u8 family,
 102              u32 initval)
 103 {
 104         switch (family) {
 105         case NFPROTO_IPV4:
 106                 queue += reciprocal_scale(hash_v4(ip_hdr(skb), initval),
 107                                           queues_total);
 108                 break;
 109         case NFPROTO_IPV6:
 110                 queue += reciprocal_scale(hash_v6(ipv6_hdr(skb), initval),
 111                                           queues_total);
 112                 break;
 113         case NFPROTO_BRIDGE:
 114                 queue += reciprocal_scale(hash_bridge(skb, initval),
 115                                           queues_total);
 116                 break;
 117         }
 118
 119         return queue;
 120 }
 121
 122 #endif /* _NF_QUEUE_H */