1 #ifndef __LINUX_NETLINK_H
2 #define __LINUX_NETLINK_H
3
4
5 #include <linux/capability.h>
6 #include <linux/skbuff.h>
7 #include <linux/export.h>
8 #include <net/scm.h>
9 #include <uapi/linux/netlink.h>
10
11 struct net;
12
nlmsg_hdr(const struct sk_buff * skb)13 static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
14 {
15 return (struct nlmsghdr *)skb->data;
16 }
17
18 enum netlink_skb_flags {
19 NETLINK_SKB_MMAPED = 0x1, /* Packet data is mmaped */
20 NETLINK_SKB_TX = 0x2, /* Packet was sent by userspace */
21 NETLINK_SKB_DELIVERED = 0x4, /* Packet was delivered */
22 NETLINK_SKB_DST = 0x8, /* Dst set in sendto or sendmsg */
23 };
24
25 struct netlink_skb_parms {
26 struct scm_creds creds; /* Skb credentials */
27 __u32 portid;
28 __u32 dst_group;
29 __u32 flags;
30 struct sock *sk;
31 bool nsid_is_set;
32 int nsid;
33 };
34
35 #define NETLINK_CB(skb) (*(struct netlink_skb_parms*)&((skb)->cb))
36 #define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds)
37
38
39 extern void netlink_table_grab(void);
40 extern void netlink_table_ungrab(void);
41
42 #define NL_CFG_F_NONROOT_RECV (1 << 0)
43 #define NL_CFG_F_NONROOT_SEND (1 << 1)
44
45 /* optional Netlink kernel configuration parameters */
46 struct netlink_kernel_cfg {
47 unsigned int groups;
48 unsigned int flags;
49 void (*input)(struct sk_buff *skb);
50 struct mutex *cb_mutex;
51 int (*bind)(struct net *net, int group);
52 void (*unbind)(struct net *net, int group);
53 bool (*compare)(struct net *net, struct sock *sk);
54 };
55
56 extern struct sock *__netlink_kernel_create(struct net *net, int unit,
57 struct module *module,
58 struct netlink_kernel_cfg *cfg);
59 static inline struct sock *
netlink_kernel_create(struct net * net,int unit,struct netlink_kernel_cfg * cfg)60 netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
61 {
62 return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
63 }
64
65 extern void netlink_kernel_release(struct sock *sk);
66 extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
67 extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
68 extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
69 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
70 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
71
72 extern struct sk_buff *__netlink_alloc_skb(struct sock *ssk, unsigned int size,
73 unsigned int ldiff, u32 dst_portid,
74 gfp_t gfp_mask);
75 static inline struct sk_buff *
netlink_alloc_skb(struct sock * ssk,unsigned int size,u32 dst_portid,gfp_t gfp_mask)76 netlink_alloc_skb(struct sock *ssk, unsigned int size, u32 dst_portid,
77 gfp_t gfp_mask)
78 {
79 return __netlink_alloc_skb(ssk, size, 0, dst_portid, gfp_mask);
80 }
81
82 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
83 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
84 __u32 group, gfp_t allocation);
85 extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
86 __u32 portid, __u32 group, gfp_t allocation,
87 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
88 void *filter_data);
89 extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
90 extern int netlink_register_notifier(struct notifier_block *nb);
91 extern int netlink_unregister_notifier(struct notifier_block *nb);
92
93 /* finegrained unicast helpers: */
94 struct sock *netlink_getsockbyfilp(struct file *filp);
95 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
96 long *timeo, struct sock *ssk);
97 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
98 int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
99
100 static inline struct sk_buff *
netlink_skb_clone(struct sk_buff * skb,gfp_t gfp_mask)101 netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
102 {
103 struct sk_buff *nskb;
104
105 nskb = skb_clone(skb, gfp_mask);
106 if (!nskb)
107 return NULL;
108
109 /* This is a large skb, set destructor callback to release head */
110 if (is_vmalloc_addr(skb->head))
111 nskb->destructor = skb->destructor;
112
113 return nskb;
114 }
115
116 /*
117 * skb should fit one page. This choice is good for headerless malloc.
118 * But we should limit to 8K so that userspace does not have to
119 * use enormous buffer sizes on recvmsg() calls just to avoid
120 * MSG_TRUNC when PAGE_SIZE is very large.
121 */
122 #if PAGE_SIZE < 8192UL
123 #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE)
124 #else
125 #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL)
126 #endif
127
128 #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
129
130
131 struct netlink_callback {
132 struct sk_buff *skb;
133 const struct nlmsghdr *nlh;
134 int (*dump)(struct sk_buff * skb,
135 struct netlink_callback *cb);
136 int (*done)(struct netlink_callback *cb);
137 void *data;
138 /* the module that dump function belong to */
139 struct module *module;
140 u16 family;
141 u16 min_dump_alloc;
142 unsigned int prev_seq, seq;
143 long args[6];
144 };
145
146 struct netlink_notify {
147 struct net *net;
148 u32 portid;
149 int protocol;
150 };
151
152 struct nlmsghdr *
153 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
154
155 struct netlink_dump_control {
156 int (*dump)(struct sk_buff *skb, struct netlink_callback *);
157 int (*done)(struct netlink_callback *);
158 void *data;
159 struct module *module;
160 u16 min_dump_alloc;
161 };
162
163 extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
164 const struct nlmsghdr *nlh,
165 struct netlink_dump_control *control);
netlink_dump_start(struct sock * ssk,struct sk_buff * skb,const struct nlmsghdr * nlh,struct netlink_dump_control * control)166 static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
167 const struct nlmsghdr *nlh,
168 struct netlink_dump_control *control)
169 {
170 if (!control->module)
171 control->module = THIS_MODULE;
172
173 return __netlink_dump_start(ssk, skb, nlh, control);
174 }
175
176 struct netlink_tap {
177 struct net_device *dev;
178 struct module *module;
179 struct list_head list;
180 };
181
182 extern int netlink_add_tap(struct netlink_tap *nt);
183 extern int netlink_remove_tap(struct netlink_tap *nt);
184
185 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
186 struct user_namespace *ns, int cap);
187 bool netlink_ns_capable(const struct sk_buff *skb,
188 struct user_namespace *ns, int cap);
189 bool netlink_capable(const struct sk_buff *skb, int cap);
190 bool netlink_net_capable(const struct sk_buff *skb, int cap);
191
192 #endif /* __LINUX_NETLINK_H */
193