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 };
  32
  33 #define NETLINK_CB(skb)         (*(struct netlink_skb_parms*)&((skb)->cb))
  34 #define NETLINK_CREDS(skb)      (&NETLINK_CB((skb)).creds)
  35
  36
  37 extern void netlink_table_grab(void);
  38 extern void netlink_table_ungrab(void);
  39
  40 #define NL_CFG_F_NONROOT_RECV   (1 << 0)
  41 #define NL_CFG_F_NONROOT_SEND   (1 << 1)
  42
  43 /* optional Netlink kernel configuration parameters */
  44 struct netlink_kernel_cfg {
  45         unsigned int    groups;
  46         unsigned int    flags;
  47         void            (*input)(struct sk_buff *skb);
  48         struct mutex    *cb_mutex;
  49         void            (*bind)(int group);
  50 };
  51
  52 extern struct sock *__netlink_kernel_create(struct net *net, int unit,
  53                                             struct module *module,
  54                                             struct netlink_kernel_cfg *cfg);
  55 static inline struct sock *
  56 netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
  57 {
  58         return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
  59 }
  60
  61 extern void netlink_kernel_release(struct sock *sk);
  62 extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
  63 extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
  64 extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
  65 extern void netlink_clear_multicast_users(struct sock *sk, unsigned int group);
  66 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
  67 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
  68 extern struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
  69                                          u32 dst_portid, gfp_t gfp_mask);
  70 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
  71 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
  72                              __u32 group, gfp_t allocation);
  73 extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
  74         __u32 portid, __u32 group, gfp_t allocation,
  75         int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
  76         void *filter_data);
  77 extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
  78 extern int netlink_register_notifier(struct notifier_block *nb);
  79 extern int netlink_unregister_notifier(struct notifier_block *nb);
  80
  81 /* finegrained unicast helpers: */
  82 struct sock *netlink_getsockbyfilp(struct file *filp);
  83 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
  84                       long *timeo, struct sock *ssk);
  85 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
  86 int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
  87
  88 /*
  89  *      skb should fit one page. This choice is good for headerless malloc.
  90  *      But we should limit to 8K so that userspace does not have to
  91  *      use enormous buffer sizes on recvmsg() calls just to avoid
  92  *      MSG_TRUNC when PAGE_SIZE is very large.
  93  */
  94 #if PAGE_SIZE < 8192UL
  95 #define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(PAGE_SIZE)
  96 #else
  97 #define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(8192UL)
  98 #endif
  99
 100 #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
 101
 102
 103 struct netlink_callback {
 104         struct sk_buff          *skb;
 105         const struct nlmsghdr   *nlh;
 106         int                     (*dump)(struct sk_buff * skb,
 107                                         struct netlink_callback *cb);
 108         int                     (*done)(struct netlink_callback *cb);
 109         void                    *data;
 110         /* the module that dump function belong to */
 111         struct module           *module;
 112         u16                     family;
 113         u16                     min_dump_alloc;
 114         unsigned int            prev_seq, seq;
 115         long                    args[6];
 116 };
 117
 118 struct netlink_notify {
 119         struct net *net;
 120         int portid;
 121         int protocol;
 122 };
 123
 124 struct nlmsghdr *
 125 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
 126
 127 struct netlink_dump_control {
 128         int (*dump)(struct sk_buff *skb, struct netlink_callback *);
 129         int (*done)(struct netlink_callback *);
 130         void *data;
 131         struct module *module;
 132         u16 min_dump_alloc;
 133 };
 134
 135 extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 136                                 const struct nlmsghdr *nlh,
 137                                 struct netlink_dump_control *control);
 138 static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 139                                      const struct nlmsghdr *nlh,
 140                                      struct netlink_dump_control *control)
 141 {
 142         if (!control->module)
 143                 control->module = THIS_MODULE;
 144
 145         return __netlink_dump_start(ssk, skb, nlh, control);
 146 }
 147
 148 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
 149                           struct user_namespace *ns, int cap);
 150 bool netlink_ns_capable(const struct sk_buff *skb,
 151                         struct user_namespace *ns, int cap);
 152 bool netlink_capable(const struct sk_buff *skb, int cap);
 153 bool netlink_net_capable(const struct sk_buff *skb, int cap);
 154
 155 #endif  /* __LINUX_NETLINK_H */