include/linux/netlink.h

   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
  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 *
  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 /**
  66  * struct netlink_ext_ack - netlink extended ACK report struct
  67  * @_msg: message string to report - don't access directly, use
  68  *      %NL_SET_ERR_MSG
  69  * @bad_attr: attribute with error
  70  */
  71 struct netlink_ext_ack {
  72         const char *_msg;
  73         const struct nlattr *bad_attr;
  74 };
  75
  76 /* Always use this macro, this allows later putting the
  77  * message into a separate section or such for things
  78  * like translation or listing all possible messages.
  79  * Currently string formatting is not supported (due
  80  * to the lack of an output buffer.)
  81  */
  82 #define NL_SET_ERR_MSG(extack, msg) do {        \
  83         static const char _msg[] = (msg);       \
  84                                                 \
  85         (extack)->_msg = _msg;                  \
  86 } while (0)
  87
  88 extern void netlink_kernel_release(struct sock *sk);
  89 extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
  90 extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
  91 extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
  92 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
  93                         const struct netlink_ext_ack *extack);
  94 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
  95
  96 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
  97 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
  98                              __u32 group, gfp_t allocation);
  99 extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
 100         __u32 portid, __u32 group, gfp_t allocation,
 101         int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
 102         void *filter_data);
 103 extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
 104 extern int netlink_register_notifier(struct notifier_block *nb);
 105 extern int netlink_unregister_notifier(struct notifier_block *nb);
 106
 107 /* finegrained unicast helpers: */
 108 struct sock *netlink_getsockbyfilp(struct file *filp);
 109 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
 110                       long *timeo, struct sock *ssk);
 111 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
 112 int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
 113
 114 static inline struct sk_buff *
 115 netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
 116 {
 117         struct sk_buff *nskb;
 118
 119         nskb = skb_clone(skb, gfp_mask);
 120         if (!nskb)
 121                 return NULL;
 122
 123         /* This is a large skb, set destructor callback to release head */
 124         if (is_vmalloc_addr(skb->head))
 125                 nskb->destructor = skb->destructor;
 126
 127         return nskb;
 128 }
 129
 130 /*
 131  *      skb should fit one page. This choice is good for headerless malloc.
 132  *      But we should limit to 8K so that userspace does not have to
 133  *      use enormous buffer sizes on recvmsg() calls just to avoid
 134  *      MSG_TRUNC when PAGE_SIZE is very large.
 135  */
 136 #if PAGE_SIZE < 8192UL
 137 #define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(PAGE_SIZE)
 138 #else
 139 #define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(8192UL)
 140 #endif
 141
 142 #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
 143
 144
 145 struct netlink_callback {
 146         struct sk_buff          *skb;
 147         const struct nlmsghdr   *nlh;
 148         int                     (*start)(struct netlink_callback *);
 149         int                     (*dump)(struct sk_buff * skb,
 150                                         struct netlink_callback *cb);
 151         int                     (*done)(struct netlink_callback *cb);
 152         void                    *data;
 153         /* the module that dump function belong to */
 154         struct module           *module;
 155         u16                     family;
 156         u16                     min_dump_alloc;
 157         unsigned int            prev_seq, seq;
 158         long                    args[6];
 159 };
 160
 161 struct netlink_notify {
 162         struct net *net;
 163         u32 portid;
 164         int protocol;
 165 };
 166
 167 struct nlmsghdr *
 168 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
 169
 170 struct netlink_dump_control {
 171         int (*start)(struct netlink_callback *);
 172         int (*dump)(struct sk_buff *skb, struct netlink_callback *);
 173         int (*done)(struct netlink_callback *);
 174         void *data;
 175         struct module *module;
 176         u16 min_dump_alloc;
 177 };
 178
 179 extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 180                                 const struct nlmsghdr *nlh,
 181                                 struct netlink_dump_control *control);
 182 static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 183                                      const struct nlmsghdr *nlh,
 184                                      struct netlink_dump_control *control)
 185 {
 186         if (!control->module)
 187                 control->module = THIS_MODULE;
 188
 189         return __netlink_dump_start(ssk, skb, nlh, control);
 190 }
 191
 192 struct netlink_tap {
 193         struct net_device *dev;
 194         struct module *module;
 195         struct list_head list;
 196 };
 197
 198 extern int netlink_add_tap(struct netlink_tap *nt);
 199 extern int netlink_remove_tap(struct netlink_tap *nt);
 200
 201 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
 202                           struct user_namespace *ns, int cap);
 203 bool netlink_ns_capable(const struct sk_buff *skb,
 204                         struct user_namespace *ns, int cap);
 205 bool netlink_capable(const struct sk_buff *skb, int cap);
 206 bool netlink_net_capable(const struct sk_buff *skb, int cap);
 207
 208 #endif  /* __LINUX_NETLINK_H */