/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __NET_GENERIC_NETLINK_H #define __NET_GENERIC_NETLINK_H #include <linux/net.h> #include <net/netlink.h> #include <net/net_namespace.h> #include <uapi/linux/genetlink.h> #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN) /* Non-parallel generic netlink requests are serialized by a global lock. */ void genl_lock(void); void genl_unlock(void); #define MODULE_ALIAS_GENL_FAMILY(family) \ MODULE_ALIAS_NET_PF_PROTO_NAME(PF_NETLINK, NETLINK_GENERIC, "-family-" family) /* Binding to multicast group requires %CAP_NET_ADMIN */ #define GENL_MCAST_CAP_NET_ADMIN BIT(0) /* Binding to multicast group requires %CAP_SYS_ADMIN */ #define GENL_MCAST_CAP_SYS_ADMIN BIT(1) /** * struct genl_multicast_group - generic netlink multicast group * @name: name of the multicast group, names are per-family * @flags: GENL_MCAST_* flags */ struct genl_multicast_group { char name[GENL_NAMSIZ]; u8 flags; }; struct genl_split_ops; struct genl_info; /** * struct genl_family - generic netlink family * @hdrsize: length of user specific header in bytes * @name: name of family * @version: protocol version * @maxattr: maximum number of attributes supported * @policy: netlink policy * @netnsok: set to true if the family can handle network * namespaces and should be presented in all of them * @parallel_ops: operations can be called in parallel and aren't * synchronized by the core genetlink code * @pre_doit: called before an operation's doit callback, it may * do additional, common, filtering and return an error * @post_doit: called after an operation's doit callback, it may * undo operations done by pre_doit, for example release locks * @bind: called when family multicast group is added to a netlink socket * @unbind: called when family multicast group is removed from a netlink socket * @module: pointer to the owning module (set to THIS_MODULE) * @mcgrps: multicast groups used by this family * @n_mcgrps: number of multicast groups * @resv_start_op: first operation for which reserved fields of the header * can be validated and policies are required (see below); * new families should leave this field at zero * @ops: the operations supported by this family * @n_ops: number of operations supported by this family * @small_ops: the small-struct operations supported by this family * @n_small_ops: number of small-struct operations supported by this family * @split_ops: the split do/dump form of operation definition * @n_split_ops: number of entries in @split_ops, note that with split do/dump * ops the number of entries is not the same as number of commands * @sock_priv_size: the size of per-socket private memory * @sock_priv_init: the per-socket private memory initializer * @sock_priv_destroy: the per-socket private memory destructor * * Attribute policies (the combination of @policy and @maxattr fields) * can be attached at the family level or at the operation level. * If both are present the per-operation policy takes precedence. * For operations before @resv_start_op lack of policy means that the core * will perform no attribute parsing or validation. For newer operations * if policy is not provided core will reject all TLV attributes. */ struct genl_family { unsigned int hdrsize; char name[GENL_NAMSIZ]; unsigned int version; unsigned int maxattr; u8 netnsok:1; u8 parallel_ops:1; u8 n_ops; u8 n_small_ops; u8 n_split_ops; u8 n_mcgrps; u8 resv_start_op; const struct nla_policy *policy; int (*pre_doit)(const struct genl_split_ops *ops, struct sk_buff *skb, struct genl_info *info); void (*post_doit)(const struct genl_split_ops *ops, struct sk_buff *skb, struct genl_info *info); int (*bind)(int mcgrp); void (*unbind)(int mcgrp); const struct genl_ops * ops; const struct genl_small_ops *small_ops; const struct genl_split_ops *split_ops; const struct genl_multicast_group *mcgrps; struct module *module; size_t sock_priv_size; void (*sock_priv_init)(void *priv); void (*sock_priv_destroy)(void *priv); /* private: internal use only */ /* protocol family identifier */ int id; /* starting number of multicast group IDs in this family */ unsigned int mcgrp_offset; /* list of per-socket privs */ struct xarray *sock_privs; }; /** * struct genl_info - receiving information * @snd_seq: sending sequence number * @snd_portid: netlink portid of sender * @family: generic netlink family * @nlhdr: netlink message header * @genlhdr: generic netlink message header * @attrs: netlink attributes * @_net: network namespace * @ctx: storage space for the use by the family * @user_ptr: user pointers (deprecated, use ctx instead) * @extack: extended ACK report struct */ struct genl_info { u32 snd_seq; u32 snd_portid; const struct genl_family *family; const struct nlmsghdr * nlhdr; struct genlmsghdr * genlhdr; struct nlattr ** attrs; possible_net_t _net; union { u8 ctx[NETLINK_CTX_SIZE]; void * user_ptr[2]; }; struct netlink_ext_ack *extack; }; static inline struct net *genl_info_net(const struct genl_info *info) { return read_pnet(&info->_net); } static inline void genl_info_net_set(struct genl_info *info, struct net *net) { write_pnet(&info->_net, net); } static inline void *genl_info_userhdr(const struct genl_info *info) { return (u8 *)info->genlhdr + GENL_HDRLEN; } #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg) #define GENL_SET_ERR_MSG_FMT(info, msg, args...) \ NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args) /* Report that a root attribute is missing */ #define GENL_REQ_ATTR_CHECK(info, attr) ({ \ const struct genl_info *__info = (info); \ \ NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \ }) enum genl_validate_flags { GENL_DONT_VALIDATE_STRICT = BIT(0), GENL_DONT_VALIDATE_DUMP = BIT(1), GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2), }; /** * struct genl_small_ops - generic netlink operations (small version) * @cmd: command identifier * @internal_flags: flags used by the family * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM) * @validate: validation flags from enum genl_validate_flags * @doit: standard command callback * @dumpit: callback for dumpers * * This is a cut-down version of struct genl_ops for users who don't need * most of the ancillary infra and want to save space. */ struct genl_small_ops { int (*doit)(struct sk_buff *skb, struct genl_info *info); int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb); u8 cmd; u8 internal_flags; u8 flags; u8 validate; }; /** * struct genl_ops - generic netlink operations * @cmd: command identifier * @internal_flags: flags used by the family * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM) * @maxattr: maximum number of attributes supported * @policy: netlink policy (takes precedence over family policy) * @validate: validation flags from enum genl_validate_flags * @doit: standard command callback * @start: start callback for dumps * @dumpit: callback for dumpers * @done: completion callback for dumps */ struct genl_ops { int (*doit)(struct sk_buff *skb, struct genl_info *info); int (*start)(struct netlink_callback *cb); int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb); int (*done)(struct netlink_callback *cb); const struct nla_policy *policy; unsigned int maxattr; u8 cmd; u8 internal_flags; u8 flags; u8 validate; }; /** * struct genl_split_ops - generic netlink operations (do/dump split version) * @cmd: command identifier * @internal_flags: flags used by the family * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM) * @validate: validation flags from enum genl_validate_flags * @policy: netlink policy (takes precedence over family policy) * @maxattr: maximum number of attributes supported * * Do callbacks: * @pre_doit: called before an operation's @doit callback, it may * do additional, common, filtering and return an error * @doit: standard command callback * @post_doit: called after an operation's @doit callback, it may * undo operations done by pre_doit, for example release locks * * Dump callbacks: * @start: start callback for dumps * @dumpit: callback for dumpers * @done: completion callback for dumps * * Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags. * Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags. * Exactly one of those flags must be set. */ struct genl_split_ops { union { struct { int (*pre_doit)(const struct genl_split_ops *ops, struct sk_buff *skb, struct genl_info *info); int (*doit)(struct sk_buff *skb, struct genl_info *info); void (*post_doit)(const struct genl_split_ops *ops, struct sk_buff *skb, struct genl_info *info); }; struct { int (*start)(struct netlink_callback *cb); int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb); int (*done)(struct netlink_callback *cb); }; }; const struct nla_policy *policy; unsigned int maxattr; u8 cmd; u8 internal_flags; u8 flags; u8 validate; }; /** * struct genl_dumpit_info - info that is available during dumpit op call * @op: generic netlink ops - for internal genl code usage * @attrs: netlink attributes * @info: struct genl_info describing the request */ struct genl_dumpit_info { struct genl_split_ops op; struct genl_info info; }; static inline const struct genl_dumpit_info * genl_dumpit_info(struct netlink_callback *cb) { return cb->data; } static inline const struct genl_info * genl_info_dump(struct netlink_callback *cb) { return &genl_dumpit_info(cb)->info; } /** * genl_info_init_ntf() - initialize genl_info for notifications * @info: genl_info struct to set up * @family: pointer to the genetlink family * @cmd: command to be used in the notification * * Initialize a locally declared struct genl_info to pass to various APIs. * Intended to be used when creating notifications. */ static inline void genl_info_init_ntf(struct genl_info *info, const struct genl_family *family, u8 cmd) { struct genlmsghdr *hdr = (void *) &info->user_ptr[0]; memset(info, 0, sizeof(*info)); info->family = family; info->genlhdr = hdr; hdr->cmd = cmd; } static inline bool genl_info_is_ntf(const struct genl_info *info) { return !info->nlhdr; } void *__genl_sk_priv_get(struct genl_family *family, struct sock *sk); void *genl_sk_priv_get(struct genl_family *family, struct sock *sk); int genl_register_family(struct genl_family *family); int genl_unregister_family(const struct genl_family *family); void genl_notify(const struct genl_family *family, struct sk_buff *skb, struct genl_info *info, u32 group, gfp_t flags); void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, const struct genl_family *family, int flags, u8 cmd); static inline void * __genlmsg_iput(struct sk_buff *skb, const struct genl_info *info, int flags) { return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family, flags, info->genlhdr->cmd); } /** * genlmsg_iput - start genetlink message based on genl_info * @skb: skb in which message header will be placed * @info: genl_info as provided to do/dump handlers * * Convenience wrapper which starts a genetlink message based on * information in user request. @info should be either the struct passed * by genetlink core to do/dump handlers (when constructing replies to * such requests) or a struct initialized by genl_info_init_ntf() * when constructing notifications. * * Returns: pointer to new genetlink header. */ static inline void * genlmsg_iput(struct sk_buff *skb, const struct genl_info *info) { return __genlmsg_iput(skb, info, 0); } /** * genlmsg_nlhdr - Obtain netlink header from user specified header * @user_hdr: user header as returned from genlmsg_put() * * Returns: pointer to netlink header. */ static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr) { return (struct nlmsghdr *)((char *)user_hdr - GENL_HDRLEN - NLMSG_HDRLEN); } /** * genlmsg_parse_deprecated - parse attributes of a genetlink message * @nlh: netlink message header * @family: genetlink message family * @tb: destination array with maxtype+1 elements * @maxtype: maximum attribute type to be expected * @policy: validation policy * @extack: extended ACK report struct */ static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh, const struct genl_family *family, struct nlattr *tb[], int maxtype, const struct nla_policy *policy, struct netlink_ext_ack *extack) { return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, policy, NL_VALIDATE_LIBERAL, extack); } /** * genlmsg_parse - parse attributes of a genetlink message * @nlh: netlink message header * @family: genetlink message family * @tb: destination array with maxtype+1 elements * @maxtype: maximum attribute type to be expected * @policy: validation policy * @extack: extended ACK report struct */ static inline int genlmsg_parse(const struct nlmsghdr *nlh, const struct genl_family *family, struct nlattr *tb[], int maxtype, const struct nla_policy *policy, struct netlink_ext_ack *extack) { return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, policy, NL_VALIDATE_STRICT, extack); } /** * genl_dump_check_consistent - check if sequence is consistent and advertise if not * @cb: netlink callback structure that stores the sequence number * @user_hdr: user header as returned from genlmsg_put() * * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it * simpler to use with generic netlink. */ static inline void genl_dump_check_consistent(struct netlink_callback *cb, void *user_hdr) { nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr)); } /** * genlmsg_put_reply - Add generic netlink header to a reply message * @skb: socket buffer holding the message * @info: receiver info * @family: generic netlink family * @flags: netlink message flags * @cmd: generic netlink command * * Returns: pointer to user specific header */ static inline void *genlmsg_put_reply(struct sk_buff *skb, struct genl_info *info, const struct genl_family *family, int flags, u8 cmd) { return genlmsg_put(skb, info->snd_portid, info->snd_seq, family, flags, cmd); } /** * genlmsg_end - Finalize a generic netlink message * @skb: socket buffer the message is stored in * @hdr: user specific header */ static inline void genlmsg_end(struct sk_buff *skb, void *hdr) { nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); } /** * genlmsg_cancel - Cancel construction of a generic netlink message * @skb: socket buffer the message is stored in * @hdr: generic netlink message header */ static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) { if (hdr) nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN); } /** * genlmsg_multicast_netns_filtered - multicast a netlink message * to a specific netns with filter * function * @family: the generic netlink family * @net: the net namespace * @skb: netlink message as socket buffer * @portid: own netlink portid to avoid sending to yourself * @group: offset of multicast group in groups array * @flags: allocation flags * @filter: filter function * @filter_data: filter function private data * * Return: 0 on success, negative error code for failure. */ static inline int genlmsg_multicast_netns_filtered(const struct genl_family *family, struct net *net, struct sk_buff *skb, u32 portid, unsigned int group, gfp_t flags, netlink_filter_fn filter, void *filter_data) { if (WARN_ON_ONCE(group >= family->n_mcgrps)) return -EINVAL; group = family->mcgrp_offset + group; return nlmsg_multicast_filtered(net->genl_sock, skb, portid, group, flags, filter, filter_data); } /** * genlmsg_multicast_netns - multicast a netlink message to a specific netns * @family: the generic netlink family * @net: the net namespace * @skb: netlink message as socket buffer * @portid: own netlink portid to avoid sending to yourself * @group: offset of multicast group in groups array * @flags: allocation flags */ static inline int genlmsg_multicast_netns(const struct genl_family *family, struct net *net, struct sk_buff *skb, u32 portid, unsigned int group, gfp_t flags) { return genlmsg_multicast_netns_filtered(family, net, skb, portid, group, flags, NULL, NULL); } /** * genlmsg_multicast - multicast a netlink message to the default netns * @family: the generic netlink family * @skb: netlink message as socket buffer * @portid: own netlink portid to avoid sending to yourself * @group: offset of multicast group in groups array * @flags: allocation flags */ static inline int genlmsg_multicast(const struct genl_family *family, struct sk_buff *skb, u32 portid, unsigned int group, gfp_t flags) { return genlmsg_multicast_netns(family, &init_net, skb, portid, group, flags); } /** * genlmsg_multicast_allns - multicast a netlink message to all net namespaces * @family: the generic netlink family * @skb: netlink message as socket buffer * @portid: own netlink portid to avoid sending to yourself * @group: offset of multicast group in groups array * * This function must hold the RTNL or rcu_read_lock(). */ int genlmsg_multicast_allns(const struct genl_family *family, struct sk_buff *skb, u32 portid, unsigned int group); /** * genlmsg_unicast - unicast a netlink message * @net: network namespace to look up @portid in * @skb: netlink message as socket buffer * @portid: netlink portid of the destination socket */ static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid) { return nlmsg_unicast(net->genl_sock, skb, portid); } /** * genlmsg_reply - reply to a request * @skb: netlink message to be sent back * @info: receiver information */ static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) { return genlmsg_unicast(genl_info_net(info), skb, info->snd_portid); } /** * genlmsg_data - head of message payload * @gnlh: genetlink message header */ static inline void *genlmsg_data(const struct genlmsghdr *gnlh) { return ((unsigned char *) gnlh + GENL_HDRLEN); } /** * genlmsg_len - length of message payload * @gnlh: genetlink message header */ static inline int genlmsg_len(const struct genlmsghdr *gnlh) { struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh - NLMSG_HDRLEN); return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN); } /** * genlmsg_msg_size - length of genetlink message not including padding * @payload: length of message payload */ static inline int genlmsg_msg_size(int payload) { return GENL_HDRLEN + payload; } /** * genlmsg_total_size - length of genetlink message including padding * @payload: length of message payload */ static inline int genlmsg_total_size(int payload) { return NLMSG_ALIGN(genlmsg_msg_size(payload)); } /** * genlmsg_new - Allocate a new generic netlink message * @payload: size of the message payload * @flags: the type of memory to allocate. */ static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags) { return nlmsg_new(genlmsg_total_size(payload), flags); } /** * genl_set_err - report error to genetlink broadcast listeners * @family: the generic netlink family * @net: the network namespace to report the error to * @portid: the PORTID of a process that we want to skip (if any) * @group: the broadcast group that will notice the error * (this is the offset of the multicast group in the groups array) * @code: error code, must be negative (as usual in kernelspace) * * This function returns the number of broadcast listeners that have set the * NETLINK_RECV_NO_ENOBUFS socket option. */ static inline int genl_set_err(const struct genl_family *family, struct net *net, u32 portid, u32 group, int code) { if (WARN_ON_ONCE(group >= family->n_mcgrps)) return -EINVAL; group = family->mcgrp_offset + group; return netlink_set_err(net->genl_sock, portid, group, code); } static inline int genl_has_listeners(const struct genl_family *family, struct net *net, unsigned int group) { if (WARN_ON_ONCE(group >= family->n_mcgrps)) return -EINVAL; group = family->mcgrp_offset + group; return netlink_has_listeners(net->genl_sock, group); } #endif /* __NET_GENERIC_NETLINK_H */
