1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _NETFILTER_NETDEV_H_
#define _NETFILTER_NETDEV_H_
#include <linux/netfilter.h>
#include <linux/netdevice.h>
#ifdef CONFIG_NETFILTER_INGRESS
static inline bool nf_hook_ingress_active(const struct sk_buff *skb)
{
#ifdef CONFIG_JUMP_LABEL
if (!static_key_false(&nf_hooks_needed[NFPROTO_NETDEV][NF_NETDEV_INGRESS]))
return false;
#endif
return rcu_access_pointer(skb->dev->nf_hooks_ingress);
}
/* caller must hold rcu_read_lock */
static inline int nf_hook_ingress(struct sk_buff *skb)
{
struct nf_hook_entries *e = rcu_dereference(skb->dev->nf_hooks_ingress);
struct nf_hook_state state;
int ret;
/* Must recheck the ingress hook head, in the event it became NULL
* after the check in nf_hook_ingress_active evaluated to true.
*/
if (unlikely(!e))
return 0;
nf_hook_state_init(&state, NF_NETDEV_INGRESS,
NFPROTO_NETDEV, skb->dev, NULL, NULL,
dev_net(skb->dev), NULL);
ret = nf_hook_slow(skb, &state, e, 0);
if (ret == 0)
return -1;
return ret;
}
#else /* CONFIG_NETFILTER_INGRESS */
static inline int nf_hook_ingress_active(struct sk_buff *skb)
{
return 0;
}
static inline int nf_hook_ingress(struct sk_buff *skb)
{
return 0;
}
#endif /* CONFIG_NETFILTER_INGRESS */
#ifdef CONFIG_NETFILTER_EGRESS
static inline bool nf_hook_egress_active(void)
{
#ifdef CONFIG_JUMP_LABEL
if (!static_key_false(&nf_hooks_needed[NFPROTO_NETDEV][NF_NETDEV_EGRESS]))
return false;
#endif
return true;
}
/**
* nf_hook_egress - classify packets before transmission
* @skb: packet to be classified
* @rc: result code which shall be returned by __dev_queue_xmit() on failure
* @dev: netdev whose egress hooks shall be applied to @skb
*
* Returns @skb on success or %NULL if the packet was consumed or filtered.
* Caller must hold rcu_read_lock.
*
* On ingress, packets are classified first by tc, then by netfilter.
* On egress, the order is reversed for symmetry. Conceptually, tc and
* netfilter can be thought of as layers, with netfilter layered above tc:
* When tc redirects a packet to another interface, netfilter is not applied
* because the packet is on the tc layer.
*
* The nf_skip_egress flag controls whether netfilter is applied on egress.
* It is updated by __netif_receive_skb_core() and __dev_queue_xmit() when the
* packet passes through tc and netfilter. Because __dev_queue_xmit() may be
* called recursively by tunnel drivers such as vxlan, the flag is reverted to
* false after sch_handle_egress(). This ensures that netfilter is applied
* both on the overlay and underlying network.
*/
static inline struct sk_buff *nf_hook_egress(struct sk_buff *skb, int *rc,
struct net_device *dev)
{
struct nf_hook_entries *e;
struct nf_hook_state state;
int ret;
#ifdef CONFIG_NETFILTER_SKIP_EGRESS
if (skb->nf_skip_egress)
return skb;
#endif
e = rcu_dereference(dev->nf_hooks_egress);
if (!e)
return skb;
nf_hook_state_init(&state, NF_NETDEV_EGRESS,
NFPROTO_NETDEV, dev, NULL, NULL,
dev_net(dev), NULL);
ret = nf_hook_slow(skb, &state, e, 0);
if (ret == 1) {
return skb;
} else if (ret < 0) {
*rc = NET_XMIT_DROP;
return NULL;
} else { /* ret == 0 */
*rc = NET_XMIT_SUCCESS;
return NULL;
}
}
#else /* CONFIG_NETFILTER_EGRESS */
static inline bool nf_hook_egress_active(void)
{
return false;
}
static inline struct sk_buff *nf_hook_egress(struct sk_buff *skb, int *rc,
struct net_device *dev)
{
return skb;
}
#endif /* CONFIG_NETFILTER_EGRESS */
static inline void nf_skip_egress(struct sk_buff *skb, bool skip)
{
#ifdef CONFIG_NETFILTER_SKIP_EGRESS
skb->nf_skip_egress = skip;
#endif
}
static inline void nf_hook_netdev_init(struct net_device *dev)
{
#ifdef CONFIG_NETFILTER_INGRESS
RCU_INIT_POINTER(dev->nf_hooks_ingress, NULL);
#endif
#ifdef CONFIG_NETFILTER_EGRESS
RCU_INIT_POINTER(dev->nf_hooks_egress, NULL);
#endif
}
#endif /* _NETFILTER_NETDEV_H_ */
|
