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 };
  23
  24 struct netlink_skb_parms {
  25         struct scm_creds        creds;          /* Skb credentials      */
  26         __u32                   portid;
  27         __u32                   dst_group;
  28         __u32                   flags;
  29         struct sock             *sk;
  30 };
  31
  32 #define NETLINK_CB(skb)         (*(struct netlink_skb_parms*)&((skb)->cb))
  33 #define NETLINK_CREDS(skb)      (&NETLINK_CB((skb)).creds)
  34
  35
  36 extern void netlink_table_grab(void);
  37 extern void netlink_table_ungrab(void);
  38
  39 #define NL_CFG_F_NONROOT_RECV   (1 << 0)
  40 #define NL_CFG_F_NONROOT_SEND   (1 << 1)
  41
  42 /* optional Netlink kernel configuration parameters */
  43 struct netlink_kernel_cfg {
  44         unsigned int    groups;
  45         unsigned int    flags;
  46         void            (*input)(struct sk_buff *skb);
  47         struct mutex    *cb_mutex;
  48         void            (*bind)(int group);
  49         bool            (*compare)(struct net *net, struct sock *sk);
  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_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
  66 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
  67 extern struct sk_buff *netlink_alloc_skb(struct sock *ssk, unsigned int size,
  68                                          u32 dst_portid, gfp_t gfp_mask);
  69 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
  70 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
  71                              __u32 group, gfp_t allocation);
  72 extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
  73         __u32 portid, __u32 group, gfp_t allocation,
  74         int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
  75         void *filter_data);
  76 extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
  77 extern int netlink_register_notifier(struct notifier_block *nb);
  78 extern int netlink_unregister_notifier(struct notifier_block *nb);
  79
  80 /* finegrained unicast helpers: */
  81 struct sock *netlink_getsockbyfilp(struct file *filp);
  82 int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
  83                       long *timeo, struct sock *ssk);
  84 void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
  85 int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
  86
  87 static inline struct sk_buff *
  88 netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
  89 {
  90         struct sk_buff *nskb;
  91
  92         nskb = skb_clone(skb, gfp_mask);
  93         if (!nskb)
  94                 return NULL;
  95
  96         /* This is a large skb, set destructor callback to release head */
  97         if (is_vmalloc_addr(skb->head))
  98                 nskb->destructor = skb->destructor;
  99
 100         return nskb;
 101 }
 102
 103 /*
 104  *      skb should fit one page. This choice is good for headerless malloc.
 105  *      But we should limit to 8K so that userspace does not have to
 106  *      use enormous buffer sizes on recvmsg() calls just to avoid
 107  *      MSG_TRUNC when PAGE_SIZE is very large.
 108  */
 109 #if PAGE_SIZE < 8192UL
 110 #define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(PAGE_SIZE)
 111 #else
 112 #define NLMSG_GOODSIZE  SKB_WITH_OVERHEAD(8192UL)
 113 #endif
 114
 115 #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
 116
 117
 118 struct netlink_callback {
 119         struct sk_buff          *skb;
 120         const struct nlmsghdr   *nlh;
 121         int                     (*dump)(struct sk_buff * skb,
 122                                         struct netlink_callback *cb);
 123         int                     (*done)(struct netlink_callback *cb);
 124         void                    *data;
 125         /* the module that dump function belong to */
 126         struct module           *module;
 127         u16                     family;
 128         u16                     min_dump_alloc;
 129         unsigned int            prev_seq, seq;
 130         long                    args[6];
 131 };
 132
 133 struct netlink_notify {
 134         struct net *net;
 135         int portid;
 136         int protocol;
 137 };
 138
 139 struct nlmsghdr *
 140 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
 141
 142 struct netlink_dump_control {
 143         int (*dump)(struct sk_buff *skb, struct netlink_callback *);
 144         int (*done)(struct netlink_callback *);
 145         void *data;
 146         struct module *module;
 147         u16 min_dump_alloc;
 148 };
 149
 150 extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 151                                 const struct nlmsghdr *nlh,
 152                                 struct netlink_dump_control *control);
 153 static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
 154                                      const struct nlmsghdr *nlh,
 155                                      struct netlink_dump_control *control)
 156 {
 157         if (!control->module)
 158                 control->module = THIS_MODULE;
 159
 160         return __netlink_dump_start(ssk, skb, nlh, control);
 161 }
 162
 163 struct netlink_tap {
 164         struct net_device *dev;
 165         struct module *module;
 166         struct list_head list;
 167 };
 168
 169 extern int netlink_add_tap(struct netlink_tap *nt);
 170 extern int netlink_remove_tap(struct netlink_tap *nt);
 171
 172 #endif  /* __LINUX_NETLINK_H */