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