linux/include/net/netfilter/nf_queue.h
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   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#include <linux/netfilter.h>
   9#include <linux/skbuff.h>
  10
  11/* Each queued (to userspace) skbuff has one of these. */
  12struct nf_queue_entry {
  13        struct list_head        list;
  14        struct sk_buff          *skb;
  15        unsigned int            id;
  16        unsigned int            hook_index;     /* index in hook_entries->hook[] */
  17
  18        struct nf_hook_state    state;
  19        u16                     size; /* sizeof(entry) + saved route keys */
  20
  21        /* extra space to store route keys */
  22};
  23
  24#define nf_queue_entry_reroute(x) ((void *)x + sizeof(struct nf_queue_entry))
  25
  26/* Packet queuing */
  27struct nf_queue_handler {
  28        int             (*outfn)(struct nf_queue_entry *entry,
  29                                 unsigned int queuenum);
  30        void            (*nf_hook_drop)(struct net *net);
  31};
  32
  33void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh);
  34void nf_unregister_queue_handler(struct net *net);
  35void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict);
  36
  37void nf_queue_entry_get_refs(struct nf_queue_entry *entry);
  38void nf_queue_entry_release_refs(struct nf_queue_entry *entry);
  39
  40static inline void init_hashrandom(u32 *jhash_initval)
  41{
  42        while (*jhash_initval == 0)
  43                *jhash_initval = prandom_u32();
  44}
  45
  46static inline u32 hash_v4(const struct iphdr *iph, u32 initval)
  47{
  48        /* packets in either direction go into same queue */
  49        if ((__force u32)iph->saddr < (__force u32)iph->daddr)
  50                return jhash_3words((__force u32)iph->saddr,
  51                        (__force u32)iph->daddr, iph->protocol, initval);
  52
  53        return jhash_3words((__force u32)iph->daddr,
  54                        (__force u32)iph->saddr, iph->protocol, initval);
  55}
  56
  57static inline u32 hash_v6(const struct ipv6hdr *ip6h, u32 initval)
  58{
  59        u32 a, b, c;
  60
  61        if ((__force u32)ip6h->saddr.s6_addr32[3] <
  62            (__force u32)ip6h->daddr.s6_addr32[3]) {
  63                a = (__force u32) ip6h->saddr.s6_addr32[3];
  64                b = (__force u32) ip6h->daddr.s6_addr32[3];
  65        } else {
  66                b = (__force u32) ip6h->saddr.s6_addr32[3];
  67                a = (__force u32) ip6h->daddr.s6_addr32[3];
  68        }
  69
  70        if ((__force u32)ip6h->saddr.s6_addr32[1] <
  71            (__force u32)ip6h->daddr.s6_addr32[1])
  72                c = (__force u32) ip6h->saddr.s6_addr32[1];
  73        else
  74                c = (__force u32) ip6h->daddr.s6_addr32[1];
  75
  76        return jhash_3words(a, b, c, initval);
  77}
  78
  79static inline u32 hash_bridge(const struct sk_buff *skb, u32 initval)
  80{
  81        struct ipv6hdr *ip6h, _ip6h;
  82        struct iphdr *iph, _iph;
  83
  84        switch (eth_hdr(skb)->h_proto) {
  85        case htons(ETH_P_IP):
  86                iph = skb_header_pointer(skb, skb_network_offset(skb),
  87                                         sizeof(*iph), &_iph);
  88                if (iph)
  89                        return hash_v4(iph, initval);
  90                break;
  91        case htons(ETH_P_IPV6):
  92                ip6h = skb_header_pointer(skb, skb_network_offset(skb),
  93                                          sizeof(*ip6h), &_ip6h);
  94                if (ip6h)
  95                        return hash_v6(ip6h, initval);
  96                break;
  97        }
  98
  99        return 0;
 100}
 101
 102static inline u32
 103nfqueue_hash(const struct sk_buff *skb, u16 queue, u16 queues_total, u8 family,
 104             u32 initval)
 105{
 106        switch (family) {
 107        case NFPROTO_IPV4:
 108                queue += reciprocal_scale(hash_v4(ip_hdr(skb), initval),
 109                                          queues_total);
 110                break;
 111        case NFPROTO_IPV6:
 112                queue += reciprocal_scale(hash_v6(ipv6_hdr(skb), initval),
 113                                          queues_total);
 114                break;
 115        case NFPROTO_BRIDGE:
 116                queue += reciprocal_scale(hash_bridge(skb, initval),
 117                                          queues_total);
 118                break;
 119        }
 120
 121        return queue;
 122}
 123
 124int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
 125             unsigned int index, unsigned int verdict);
 126
 127#endif /* _NF_QUEUE_H */
 128