| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef __LINUX_NETLINK_H |
| 3 | #define __LINUX_NETLINK_H |
| 4 | |
| 5 | |
| 6 | #include <linux/capability.h> |
| 7 | #include <linux/skbuff.h> |
| 8 | #include <linux/export.h> |
| 9 | #include <net/scm.h> |
| 10 | #include <uapi/linux/netlink.h> |
| 11 | |
| 12 | struct net; |
| 13 | |
| 14 | static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb) |
| 15 | { |
| 16 | return (struct nlmsghdr *)skb->data; |
| 17 | } |
| 18 | |
| 19 | enum netlink_skb_flags { |
| 20 | NETLINK_SKB_MMAPED = 0x1, /* Packet data is mmaped */ |
| 21 | NETLINK_SKB_TX = 0x2, /* Packet was sent by userspace */ |
| 22 | NETLINK_SKB_DELIVERED = 0x4, /* Packet was delivered */ |
| 23 | NETLINK_SKB_DST = 0x8, /* Dst set in sendto or sendmsg */ |
| 24 | }; |
| 25 | |
| 26 | struct netlink_skb_parms { |
| 27 | struct scm_creds creds; /* Skb credentials */ |
| 28 | __u32 portid; |
| 29 | __u32 dst_group; |
| 30 | __u32 flags; |
| 31 | struct sock *sk; |
| 32 | bool nsid_is_set; |
| 33 | int nsid; |
| 34 | }; |
| 35 | |
| 36 | #define NETLINK_CB(skb) (*(struct netlink_skb_parms*)&((skb)->cb)) |
| 37 | #define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds) |
| 38 | |
| 39 | |
| 40 | extern void netlink_table_grab(void); |
| 41 | extern void netlink_table_ungrab(void); |
| 42 | |
| 43 | #define NL_CFG_F_NONROOT_RECV (1 << 0) |
| 44 | #define NL_CFG_F_NONROOT_SEND (1 << 1) |
| 45 | |
| 46 | /* optional Netlink kernel configuration parameters */ |
| 47 | struct netlink_kernel_cfg { |
| 48 | unsigned int groups; |
| 49 | unsigned int flags; |
| 50 | void (*input)(struct sk_buff *skb); |
| 51 | struct mutex *cb_mutex; |
| 52 | int (*bind)(struct net *net, int group); |
| 53 | void (*unbind)(struct net *net, int group); |
| 54 | bool (*compare)(struct net *net, struct sock *sk); |
| 55 | }; |
| 56 | |
| 57 | extern struct sock *__netlink_kernel_create(struct net *net, int unit, |
| 58 | struct module *module, |
| 59 | struct netlink_kernel_cfg *cfg); |
| 60 | static inline struct sock * |
| 61 | netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg) |
| 62 | { |
| 63 | return __netlink_kernel_create(net, unit, THIS_MODULE, cfg); |
| 64 | } |
| 65 | |
| 66 | /* this can be increased when necessary - don't expose to userland */ |
| 67 | #define NETLINK_MAX_COOKIE_LEN 20 |
| 68 | |
| 69 | /** |
| 70 | * struct netlink_ext_ack - netlink extended ACK report struct |
| 71 | * @_msg: message string to report - don't access directly, use |
| 72 | * %NL_SET_ERR_MSG |
| 73 | * @bad_attr: attribute with error |
| 74 | * @cookie: cookie data to return to userspace (for success) |
| 75 | * @cookie_len: actual cookie data length |
| 76 | */ |
| 77 | struct netlink_ext_ack { |
| 78 | const char *_msg; |
| 79 | const struct nlattr *bad_attr; |
| 80 | u8 cookie[NETLINK_MAX_COOKIE_LEN]; |
| 81 | u8 cookie_len; |
| 82 | }; |
| 83 | |
| 84 | /* Always use this macro, this allows later putting the |
| 85 | * message into a separate section or such for things |
| 86 | * like translation or listing all possible messages. |
| 87 | * Currently string formatting is not supported (due |
| 88 | * to the lack of an output buffer.) |
| 89 | */ |
| 90 | #define NL_SET_ERR_MSG(extack, msg) do { \ |
| 91 | static const char __msg[] = (msg); \ |
| 92 | struct netlink_ext_ack *__extack = (extack); \ |
| 93 | \ |
| 94 | if (__extack) \ |
| 95 | __extack->_msg = __msg; \ |
| 96 | } while (0) |
| 97 | |
| 98 | #define NL_SET_ERR_MSG_MOD(extack, msg) \ |
| 99 | NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg) |
| 100 | |
| 101 | #define NL_SET_BAD_ATTR(extack, attr) do { \ |
| 102 | if ((extack)) \ |
| 103 | (extack)->bad_attr = (attr); \ |
| 104 | } while (0) |
| 105 | |
| 106 | #define NL_SET_ERR_MSG_ATTR(extack, attr, msg) do { \ |
| 107 | static const char __msg[] = (msg); \ |
| 108 | struct netlink_ext_ack *__extack = (extack); \ |
| 109 | \ |
| 110 | if (__extack) { \ |
| 111 | __extack->_msg = __msg; \ |
| 112 | __extack->bad_attr = (attr); \ |
| 113 | } \ |
| 114 | } while (0) |
| 115 | |
| 116 | extern void netlink_kernel_release(struct sock *sk); |
| 117 | extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups); |
| 118 | extern int netlink_change_ngroups(struct sock *sk, unsigned int groups); |
| 119 | extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group); |
| 120 | extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, |
| 121 | const struct netlink_ext_ack *extack); |
| 122 | extern int netlink_has_listeners(struct sock *sk, unsigned int group); |
| 123 | |
| 124 | extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock); |
| 125 | extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid, |
| 126 | __u32 group, gfp_t allocation); |
| 127 | extern int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, |
| 128 | __u32 portid, __u32 group, gfp_t allocation, |
| 129 | int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data), |
| 130 | void *filter_data); |
| 131 | extern int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code); |
| 132 | extern int netlink_register_notifier(struct notifier_block *nb); |
| 133 | extern int netlink_unregister_notifier(struct notifier_block *nb); |
| 134 | |
| 135 | /* finegrained unicast helpers: */ |
| 136 | struct sock *netlink_getsockbyfilp(struct file *filp); |
| 137 | int netlink_attachskb(struct sock *sk, struct sk_buff *skb, |
| 138 | long *timeo, struct sock *ssk); |
| 139 | void netlink_detachskb(struct sock *sk, struct sk_buff *skb); |
| 140 | int netlink_sendskb(struct sock *sk, struct sk_buff *skb); |
| 141 | |
| 142 | static inline struct sk_buff * |
| 143 | netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask) |
| 144 | { |
| 145 | struct sk_buff *nskb; |
| 146 | |
| 147 | nskb = skb_clone(skb, gfp_mask); |
| 148 | if (!nskb) |
| 149 | return NULL; |
| 150 | |
| 151 | /* This is a large skb, set destructor callback to release head */ |
| 152 | if (is_vmalloc_addr(skb->head)) |
| 153 | nskb->destructor = skb->destructor; |
| 154 | |
| 155 | return nskb; |
| 156 | } |
| 157 | |
| 158 | /* |
| 159 | * skb should fit one page. This choice is good for headerless malloc. |
| 160 | * But we should limit to 8K so that userspace does not have to |
| 161 | * use enormous buffer sizes on recvmsg() calls just to avoid |
| 162 | * MSG_TRUNC when PAGE_SIZE is very large. |
| 163 | */ |
| 164 | #if PAGE_SIZE < 8192UL |
| 165 | #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE) |
| 166 | #else |
| 167 | #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL) |
| 168 | #endif |
| 169 | |
| 170 | #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN) |
| 171 | |
| 172 | |
| 173 | struct netlink_callback { |
| 174 | struct sk_buff *skb; |
| 175 | const struct nlmsghdr *nlh; |
| 176 | int (*start)(struct netlink_callback *); |
| 177 | int (*dump)(struct sk_buff * skb, |
| 178 | struct netlink_callback *cb); |
| 179 | int (*done)(struct netlink_callback *cb); |
| 180 | void *data; |
| 181 | /* the module that dump function belong to */ |
| 182 | struct module *module; |
| 183 | u16 family; |
| 184 | u16 min_dump_alloc; |
| 185 | unsigned int prev_seq, seq; |
| 186 | long args[6]; |
| 187 | }; |
| 188 | |
| 189 | struct netlink_notify { |
| 190 | struct net *net; |
| 191 | u32 portid; |
| 192 | int protocol; |
| 193 | }; |
| 194 | |
| 195 | struct nlmsghdr * |
| 196 | __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags); |
| 197 | |
| 198 | struct netlink_dump_control { |
| 199 | int (*start)(struct netlink_callback *); |
| 200 | int (*dump)(struct sk_buff *skb, struct netlink_callback *); |
| 201 | int (*done)(struct netlink_callback *); |
| 202 | void *data; |
| 203 | struct module *module; |
| 204 | u16 min_dump_alloc; |
| 205 | }; |
| 206 | |
| 207 | extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, |
| 208 | const struct nlmsghdr *nlh, |
| 209 | struct netlink_dump_control *control); |
| 210 | static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, |
| 211 | const struct nlmsghdr *nlh, |
| 212 | struct netlink_dump_control *control) |
| 213 | { |
| 214 | if (!control->module) |
| 215 | control->module = THIS_MODULE; |
| 216 | |
| 217 | return __netlink_dump_start(ssk, skb, nlh, control); |
| 218 | } |
| 219 | |
| 220 | struct netlink_tap { |
| 221 | struct net_device *dev; |
| 222 | struct module *module; |
| 223 | struct list_head list; |
| 224 | }; |
| 225 | |
| 226 | extern int netlink_add_tap(struct netlink_tap *nt); |
| 227 | extern int netlink_remove_tap(struct netlink_tap *nt); |
| 228 | |
| 229 | bool __netlink_ns_capable(const struct netlink_skb_parms *nsp, |
| 230 | struct user_namespace *ns, int cap); |
| 231 | bool netlink_ns_capable(const struct sk_buff *skb, |
| 232 | struct user_namespace *ns, int cap); |
| 233 | bool netlink_capable(const struct sk_buff *skb, int cap); |
| 234 | bool netlink_net_capable(const struct sk_buff *skb, int cap); |
| 235 | |
| 236 | #endif /* __LINUX_NETLINK_H */ |