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 /* this can be increased when necessary - don't expose to userland */ 66 #define NETLINK_MAX_COOKIE_LEN 20 67 68 /** 69 * struct netlink_ext_ack - netlink extended ACK report struct 70 * @_msg: message string to report - don't access directly, use 71 * %NL_SET_ERR_MSG 72 * @bad_attr: attribute with error 73 * @cookie: cookie data to return to userspace (for success) 74 * @cookie_len: actual cookie data length 75 */ 76 struct netlink_ext_ack { 77 const char *_msg; 78 const struct nlattr *bad_attr; 79 u8 cookie[NETLINK_MAX_COOKIE_LEN]; 80 u8 cookie_len; 81 }; 82 83 /* Always use this macro, this allows later putting the 84 * message into a separate section or such for things 85 * like translation or listing all possible messages. 86 * Currently string formatting is not supported (due 87 * to the lack of an output buffer.) 88 */ 89 #define NL_SET_ERR_MSG(extack, msg) do { \ 90 static const char __msg[] = (msg); \ 91 struct netlink_ext_ack *__extack = (extack); \ 92 \ 93 if (__extack) \ 94 __extack->_msg = __msg; \ 95 } while (0) 96 97 #define NL_SET_ERR_MSG_MOD(extack, msg) \ 98 NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg) 99 100 #define NL_SET_BAD_ATTR(extack, attr) do { \ 101 if ((extack)) \ 102 (extack)->bad_attr = (attr); \ 103 } while (0) 104 105 #define NL_SET_ERR_MSG_ATTR(extack, attr, msg) do { \ 106 static const char __msg[] = (msg); \ 107 struct netlink_ext_ack *__extack = (extack); \ 108 \ 109 if (__extack) { \ 110 __extack->_msg = __msg; \ 111 __extack->bad_attr = (attr); \ 112 } \ 113 } while (0) 114 115 extern void netlink_kernel_release(struct sock *sk); 116 extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups); 117 extern int netlink_change_ngroups(struct sock *sk, unsigned int groups); 118 extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group); 119 extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, 120 const struct netlink_ext_ack *extack); 121 extern int netlink_has_listeners(struct sock *sk, unsigned int group); 122 123 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock); 124 extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid, 125 __u32 group, gfp_t allocation); 126 extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, 127 __u32 portid, __u32 group, gfp_t allocation, 128 int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data), 129 void *filter_data); 130 extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code); 131 extern int netlink_register_notifier(struct notifier_block *nb); 132 extern int netlink_unregister_notifier(struct notifier_block *nb); 133 134 /* finegrained unicast helpers: */ 135 struct sock *netlink_getsockbyfilp(struct file *filp); 136 int netlink_attachskb(struct sock *sk, struct sk_buff *skb, 137 long *timeo, struct sock *ssk); 138 void netlink_detachskb(struct sock *sk, struct sk_buff *skb); 139 int netlink_sendskb(struct sock *sk, struct sk_buff *skb); 140 141 static inline struct sk_buff * 142 netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask) 143 { 144 struct sk_buff *nskb; 145 146 nskb = skb_clone(skb, gfp_mask); 147 if (!nskb) 148 return NULL; 149 150 /* This is a large skb, set destructor callback to release head */ 151 if (is_vmalloc_addr(skb->head)) 152 nskb->destructor = skb->destructor; 153 154 return nskb; 155 } 156 157 /* 158 * skb should fit one page. This choice is good for headerless malloc. 159 * But we should limit to 8K so that userspace does not have to 160 * use enormous buffer sizes on recvmsg() calls just to avoid 161 * MSG_TRUNC when PAGE_SIZE is very large. 162 */ 163 #if PAGE_SIZE < 8192UL 164 #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE) 165 #else 166 #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL) 167 #endif 168 169 #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN) 170 171 172 struct netlink_callback { 173 struct sk_buff *skb; 174 const struct nlmsghdr *nlh; 175 int (*start)(struct netlink_callback *); 176 int (*dump)(struct sk_buff * skb, 177 struct netlink_callback *cb); 178 int (*done)(struct netlink_callback *cb); 179 void *data; 180 /* the module that dump function belong to */ 181 struct module *module; 182 u16 family; 183 u16 min_dump_alloc; 184 unsigned int prev_seq, seq; 185 long args[6]; 186 }; 187 188 struct netlink_notify { 189 struct net *net; 190 u32 portid; 191 int protocol; 192 }; 193 194 struct nlmsghdr * 195 __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags); 196 197 struct netlink_dump_control { 198 int (*start)(struct netlink_callback *); 199 int (*dump)(struct sk_buff *skb, struct netlink_callback *); 200 int (*done)(struct netlink_callback *); 201 void *data; 202 struct module *module; 203 u16 min_dump_alloc; 204 }; 205 206 extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 207 const struct nlmsghdr *nlh, 208 struct netlink_dump_control *control); 209 static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, 210 const struct nlmsghdr *nlh, 211 struct netlink_dump_control *control) 212 { 213 if (!control->module) 214 control->module = THIS_MODULE; 215 216 return __netlink_dump_start(ssk, skb, nlh, control); 217 } 218 219 struct netlink_tap { 220 struct net_device *dev; 221 struct module *module; 222 struct list_head list; 223 }; 224 225 extern int netlink_add_tap(struct netlink_tap *nt); 226 extern int netlink_remove_tap(struct netlink_tap *nt); 227 228 bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, 229 struct user_namespace *ns, int cap); 230 bool netlink_ns_capable(const struct sk_buff *skb, 231 struct user_namespace *ns, int cap); 232 bool netlink_capable(const struct sk_buff *skb, int cap); 233 bool netlink_net_capable(const struct sk_buff *skb, int cap); 234 235 #endif /* __LINUX_NETLINK_H */ 236