/* 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
* @user_ptr: user pointers
* @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;
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
* @flags: allocation flags
*
* 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, gfp_t flags);
/**
* 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 */
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