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 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 *
  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 *
 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                     (*start)(struct netlink_callback *);
 135         int                     (*dump)(struct sk_buff * skb,
 136                                         struct netlink_callback *cb);
 137         int                     (*done)(struct netlink_callback *cb);
 138         void                    *data;
 139         /* the module that dump function belong to */
 140         struct module           *module;
 141         u16                     family;
 142         u16                     min_dump_alloc;
 143         unsigned int            prev_seq, seq;
 144         long                    args[6];
 145 };
 146
 147 struct netlink_notify {
 148         struct net *net;
 149         u32 portid;
 150         int protocol;
 151 };
 152
 153 struct nlmsghdr *
 154 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
 155
 156 struct netlink_dump_control {
 157         int (*start)(struct netlink_callback *);
 158         int (*dump)(struct sk_buff *skb, struct netlink_callback *);
 159         int (*done)(struct netlink_callback *);
 160         void *data;
 161         struct module *module;
 162         u16 min_dump_alloc;
 163 };
 164
 165 extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 166                                 const struct nlmsghdr *nlh,
 167                                 struct netlink_dump_control *control);
 168 static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 169                                      const struct nlmsghdr *nlh,
 170                                      struct netlink_dump_control *control)
 171 {
 172         if (!control->module)
 173                 control->module = THIS_MODULE;
 174
 175         return __netlink_dump_start(ssk, skb, nlh, control);
 176 }
 177
 178 struct netlink_tap {
 179         struct net_device *dev;
 180         struct module *module;
 181         struct list_head list;
 182 };
 183
 184 extern int netlink_add_tap(struct netlink_tap *nt);
 185 extern int netlink_remove_tap(struct netlink_tap *nt);
 186
 187 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
 188                           struct user_namespace *ns, int cap);
 189 bool netlink_ns_capable(const struct sk_buff *skb,
 190                         struct user_namespace *ns, int cap);
 191 bool netlink_capable(const struct sk_buff *skb, int cap);
 192 bool netlink_net_capable(const struct sk_buff *skb, int cap);
 193
 194 #endif  /* __LINUX_NETLINK_H */