Merge tag 'trace-printf-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...

[drm/drm-misc.git] / include / net / genetlink.h

/* 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, not 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 */