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#include <linux/netfilter.h>
  9#include <linux/rhashtable-types.h>
 10#include <linux/skbuff.h>
 11
 12/* Each queued (to userspace) skbuff has one of these. */
 13struct nf_queue_entry {
 14	struct list_head	list;
 15	struct rhash_head	hash_node;
 16	struct sk_buff		*skb;
 17	unsigned int		id;
 18	unsigned int		hook_index;	/* index in hook_entries->hook[] */
 19#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
 20	struct net_device	*physin;
 21	struct net_device	*physout;
 22#endif
 23	struct nf_hook_state	state;
 24	bool			nf_ct_is_unconfirmed;
 25	u16			size; /* sizeof(entry) + saved route keys */
 26
 27	/* extra space to store route keys */
 28};
 29
 30#define nf_queue_entry_reroute(x) ((void *)x + sizeof(struct nf_queue_entry))
 31
 32/* Packet queuing */
 33struct nf_queue_handler {
 34	int		(*outfn)(struct nf_queue_entry *entry,
 35				 unsigned int queuenum);
 36	void		(*nf_hook_drop)(struct net *net);
 37};
 38
 39void nf_register_queue_handler(const struct nf_queue_handler *qh);
 40void nf_unregister_queue_handler(void);
 41
 42bool nf_queue_entry_get_refs(struct nf_queue_entry *entry);
 43void nf_queue_entry_free(struct nf_queue_entry *entry);
 44
 45static inline void init_hashrandom(u32 *jhash_initval)
 46{
 47	while (*jhash_initval == 0)
 48		*jhash_initval = get_random_u32();
 49}
 50
 51static inline u32 hash_v4(const struct iphdr *iph, u32 initval)
 52{
 53	/* packets in either direction go into same queue */
 54	if ((__force u32)iph->saddr < (__force u32)iph->daddr)
 55		return jhash_3words((__force u32)iph->saddr,
 56			(__force u32)iph->daddr, iph->protocol, initval);
 57
 58	return jhash_3words((__force u32)iph->daddr,
 59			(__force u32)iph->saddr, iph->protocol, initval);
 60}
 61
 62static inline u32 hash_v6(const struct ipv6hdr *ip6h, u32 initval)
 63{
 64	u32 a, b, c;
 65
 66	if ((__force u32)ip6h->saddr.s6_addr32[3] <
 67	    (__force u32)ip6h->daddr.s6_addr32[3]) {
 68		a = (__force u32) ip6h->saddr.s6_addr32[3];
 69		b = (__force u32) ip6h->daddr.s6_addr32[3];
 70	} else {
 71		b = (__force u32) ip6h->saddr.s6_addr32[3];
 72		a = (__force u32) ip6h->daddr.s6_addr32[3];
 73	}
 74
 75	if ((__force u32)ip6h->saddr.s6_addr32[1] <
 76	    (__force u32)ip6h->daddr.s6_addr32[1])
 77		c = (__force u32) ip6h->saddr.s6_addr32[1];
 78	else
 79		c = (__force u32) ip6h->daddr.s6_addr32[1];
 80
 81	return jhash_3words(a, b, c, initval);
 82}
 83
 84static inline u32 hash_bridge(const struct sk_buff *skb, u32 initval)
 85{
 86	struct ipv6hdr *ip6h, _ip6h;
 87	struct iphdr *iph, _iph;
 88
 89	switch (eth_hdr(skb)->h_proto) {
 90	case htons(ETH_P_IP):
 91		iph = skb_header_pointer(skb, skb_network_offset(skb),
 92					 sizeof(*iph), &_iph);
 93		if (iph)
 94			return hash_v4(iph, initval);
 95		break;
 96	case htons(ETH_P_IPV6):
 97		ip6h = skb_header_pointer(skb, skb_network_offset(skb),
 98					  sizeof(*ip6h), &_ip6h);
 99		if (ip6h)
100			return hash_v6(ip6h, initval);
101		break;
102	}
103
104	return 0;
105}
106
107static inline u32
108nfqueue_hash(const struct sk_buff *skb, u16 queue, u16 queues_total, u8 family,
109	     u32 initval)
110{
111	switch (family) {
112	case NFPROTO_IPV4:
113		queue += reciprocal_scale(hash_v4(ip_hdr(skb), initval),
114					  queues_total);
115		break;
116	case NFPROTO_IPV6:
117		queue += reciprocal_scale(hash_v6(ipv6_hdr(skb), initval),
118					  queues_total);
119		break;
120	case NFPROTO_BRIDGE:
121		queue += reciprocal_scale(hash_bridge(skb, initval),
122					  queues_total);
123		break;
124	}
125
126	return queue;
127}
128
129int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
130	     unsigned int index, unsigned int verdict);
131
132#endif /* _NF_QUEUE_H */