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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef __LINUX_NETLINK_H
- #define __LINUX_NETLINK_H
- #include <linux/capability.h>
- #include <linux/skbuff.h>
- #include <linux/export.h>
- #include <net/scm.h>
- #include <uapi/linux/netlink.h>
- struct net;
- void do_trace_netlink_extack(const char *msg);
- static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
- {
- return (struct nlmsghdr *)skb->data;
- }
- enum netlink_skb_flags {
- NETLINK_SKB_DST = 0x8, /* Dst set in sendto or sendmsg */
- };
- struct netlink_skb_parms {
- struct scm_creds creds; /* Skb credentials */
- __u32 portid;
- __u32 dst_group;
- __u32 flags;
- struct sock *sk;
- bool nsid_is_set;
- int nsid;
- };
- #define NETLINK_CB(skb) (*(struct netlink_skb_parms*)&((skb)->cb))
- #define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds)
- void netlink_table_grab(void);
- void netlink_table_ungrab(void);
- #define NL_CFG_F_NONROOT_RECV (1 << 0)
- #define NL_CFG_F_NONROOT_SEND (1 << 1)
- /* optional Netlink kernel configuration parameters */
- struct netlink_kernel_cfg {
- unsigned int groups;
- unsigned int flags;
- void (*input)(struct sk_buff *skb);
- struct mutex *cb_mutex;
- int (*bind)(struct net *net, int group);
- void (*unbind)(struct net *net, int group);
- bool (*compare)(struct net *net, struct sock *sk);
- };
- struct sock *__netlink_kernel_create(struct net *net, int unit,
- struct module *module,
- struct netlink_kernel_cfg *cfg);
- static inline struct sock *
- netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
- {
- return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
- }
- /* this can be increased when necessary - don't expose to userland */
- #define NETLINK_MAX_COOKIE_LEN 20
- /**
- * struct netlink_ext_ack - netlink extended ACK report struct
- * @_msg: message string to report - don't access directly, use
- * %NL_SET_ERR_MSG
- * @bad_attr: attribute with error
- * @policy: policy for a bad attribute
- * @miss_type: attribute type which was missing
- * @miss_nest: nest missing an attribute (%NULL if missing top level attr)
- * @cookie: cookie data to return to userspace (for success)
- * @cookie_len: actual cookie data length
- */
- struct netlink_ext_ack {
- const char *_msg;
- const struct nlattr *bad_attr;
- const struct nla_policy *policy;
- const struct nlattr *miss_nest;
- u16 miss_type;
- u8 cookie[NETLINK_MAX_COOKIE_LEN];
- u8 cookie_len;
- };
- /* Always use this macro, this allows later putting the
- * message into a separate section or such for things
- * like translation or listing all possible messages.
- * Currently string formatting is not supported (due
- * to the lack of an output buffer.)
- */
- #define NL_SET_ERR_MSG(extack, msg) do { \
- static const char __msg[] = msg; \
- struct netlink_ext_ack *__extack = (extack); \
- \
- do_trace_netlink_extack(__msg); \
- \
- if (__extack) \
- __extack->_msg = __msg; \
- } while (0)
- #define NL_SET_ERR_MSG_MOD(extack, msg) \
- NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg)
- #define NL_SET_BAD_ATTR_POLICY(extack, attr, pol) do { \
- if ((extack)) { \
- (extack)->bad_attr = (attr); \
- (extack)->policy = (pol); \
- } \
- } while (0)
- #define NL_SET_BAD_ATTR(extack, attr) NL_SET_BAD_ATTR_POLICY(extack, attr, NULL)
- #define NL_SET_ERR_MSG_ATTR_POL(extack, attr, pol, msg) do { \
- static const char __msg[] = msg; \
- struct netlink_ext_ack *__extack = (extack); \
- \
- do_trace_netlink_extack(__msg); \
- \
- if (__extack) { \
- __extack->_msg = __msg; \
- __extack->bad_attr = (attr); \
- __extack->policy = (pol); \
- } \
- } while (0)
- #define NL_SET_ERR_MSG_ATTR(extack, attr, msg) \
- NL_SET_ERR_MSG_ATTR_POL(extack, attr, NULL, msg)
- #define NL_SET_ERR_ATTR_MISS(extack, nest, type) do { \
- struct netlink_ext_ack *__extack = (extack); \
- \
- if (__extack) { \
- __extack->miss_nest = (nest); \
- __extack->miss_type = (type); \
- } \
- } while (0)
- #define NL_REQ_ATTR_CHECK(extack, nest, tb, type) ({ \
- struct nlattr **__tb = (tb); \
- u32 __attr = (type); \
- int __retval; \
- \
- __retval = !__tb[__attr]; \
- if (__retval) \
- NL_SET_ERR_ATTR_MISS((extack), (nest), __attr); \
- __retval; \
- })
- static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack,
- u64 cookie)
- {
- if (!extack)
- return;
- memcpy(extack->cookie, &cookie, sizeof(cookie));
- extack->cookie_len = sizeof(cookie);
- }
- void netlink_kernel_release(struct sock *sk);
- int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
- int netlink_change_ngroups(struct sock *sk, unsigned int groups);
- void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
- void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
- const struct netlink_ext_ack *extack);
- int netlink_has_listeners(struct sock *sk, unsigned int group);
- bool netlink_strict_get_check(struct sk_buff *skb);
- int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
- int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
- __u32 group, gfp_t allocation);
- int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
- int netlink_register_notifier(struct notifier_block *nb);
- int netlink_unregister_notifier(struct notifier_block *nb);
- /* finegrained unicast helpers: */
- struct sock *netlink_getsockbyfilp(struct file *filp);
- int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
- long *timeo, struct sock *ssk);
- void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
- int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
- static inline struct sk_buff *
- netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
- {
- struct sk_buff *nskb;
- nskb = skb_clone(skb, gfp_mask);
- if (!nskb)
- return NULL;
- /* This is a large skb, set destructor callback to release head */
- if (is_vmalloc_addr(skb->head))
- nskb->destructor = skb->destructor;
- return nskb;
- }
- /*
- * skb should fit one page. This choice is good for headerless malloc.
- * But we should limit to 8K so that userspace does not have to
- * use enormous buffer sizes on recvmsg() calls just to avoid
- * MSG_TRUNC when PAGE_SIZE is very large.
- */
- #if PAGE_SIZE < 8192UL
- #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE)
- #else
- #define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL)
- #endif
- #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
- struct netlink_callback {
- struct sk_buff *skb;
- const struct nlmsghdr *nlh;
- int (*dump)(struct sk_buff * skb,
- struct netlink_callback *cb);
- int (*done)(struct netlink_callback *cb);
- void *data;
- /* the module that dump function belong to */
- struct module *module;
- struct netlink_ext_ack *extack;
- u16 family;
- u16 answer_flags;
- u32 min_dump_alloc;
- unsigned int prev_seq, seq;
- bool strict_check;
- union {
- u8 ctx[48];
- /* args is deprecated. Cast a struct over ctx instead
- * for proper type safety.
- */
- long args[6];
- };
- };
- struct netlink_notify {
- struct net *net;
- u32 portid;
- int protocol;
- };
- struct nlmsghdr *
- __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
- struct netlink_dump_control {
- int (*start)(struct netlink_callback *);
- int (*dump)(struct sk_buff *skb, struct netlink_callback *);
- int (*done)(struct netlink_callback *);
- void *data;
- struct module *module;
- u32 min_dump_alloc;
- };
- int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
- const struct nlmsghdr *nlh,
- struct netlink_dump_control *control);
- static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
- const struct nlmsghdr *nlh,
- struct netlink_dump_control *control)
- {
- if (!control->module)
- control->module = THIS_MODULE;
- return __netlink_dump_start(ssk, skb, nlh, control);
- }
- struct netlink_tap {
- struct net_device *dev;
- struct module *module;
- struct list_head list;
- };
- int netlink_add_tap(struct netlink_tap *nt);
- int netlink_remove_tap(struct netlink_tap *nt);
- bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
- struct user_namespace *ns, int cap);
- bool netlink_ns_capable(const struct sk_buff *skb,
- struct user_namespace *ns, int cap);
- bool netlink_capable(const struct sk_buff *skb, int cap);
- bool netlink_net_capable(const struct sk_buff *skb, int cap);
- #endif /* __LINUX_NETLINK_H */
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