diff options
Diffstat (limited to 'include/net/genetlink.h')
| -rw-r--r-- | include/net/genetlink.h | 267 |
1 files changed, 235 insertions, 32 deletions
diff --git a/include/net/genetlink.h b/include/net/genetlink.h index e55ec1597ce7..a03d56765832 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -2,26 +2,40 @@ #ifndef __NET_GENERIC_NETLINK_H #define __NET_GENERIC_NETLINK_H -#include <linux/genetlink.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_ops; +struct genl_split_ops; struct genl_info; /** * struct genl_family - generic netlink family - * @id: protocol family identifier (private) * @hdrsize: length of user specific header in bytes * @name: name of family * @version: protocol version @@ -35,65 +49,101 @@ struct genl_info; * 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 - * @mcgrp_offset: starting number of multicast group IDs in this family - * (private) + * @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 { - int id; /* private */ unsigned int hdrsize; char name[GENL_NAMSIZ]; unsigned int version; unsigned int maxattr; - unsigned int mcgrp_offset; /* private */ 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_ops *ops, + int (*pre_doit)(const struct genl_split_ops *ops, struct sk_buff *skb, struct genl_info *info); - void (*post_doit)(const struct genl_ops *ops, + 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 - * @userhdr: user specific header * @attrs: netlink attributes * @_net: network namespace - * @user_ptr: user pointers + * @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; - struct nlmsghdr * nlhdr; + const struct genl_family *family; + const struct nlmsghdr * nlhdr; struct genlmsghdr * genlhdr; - void * userhdr; struct nlattr ** attrs; possible_net_t _net; - void * user_ptr[2]; + union { + u8 ctx[NETLINK_CTX_SIZE]; + void * user_ptr[2]; + }; struct netlink_ext_ack *extack; }; -static inline struct net *genl_info_net(struct genl_info *info) +static inline struct net *genl_info_net(const struct genl_info *info) { return read_pnet(&info->_net); } @@ -103,8 +153,23 @@ 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), @@ -115,7 +180,7 @@ enum genl_validate_flags { * struct genl_small_ops - generic netlink operations (small version) * @cmd: command identifier * @internal_flags: flags used by the family - * @flags: flags + * @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 @@ -136,7 +201,7 @@ struct genl_small_ops { * struct genl_ops - generic netlink operations * @cmd: command identifier * @internal_flags: flags used by the family - * @flags: flags + * @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 @@ -161,15 +226,66 @@ struct genl_ops { }; /** - * struct genl_info - info that is available during dumpit op call - * @family: generic netlink family - for internal genl code usage - * @ops: generic netlink ops - for internal genl code usage + * 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 { - const struct genl_family *family; - struct genl_ops op; - struct nlattr **attrs; + struct genl_split_ops op; + struct genl_info info; }; static inline const struct genl_dumpit_info * @@ -178,6 +294,40 @@ 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, @@ -186,11 +336,37 @@ void genl_notify(const struct genl_family *family, struct sk_buff *skb, 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. + * Returns: pointer to netlink header. */ static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr) { @@ -259,7 +435,7 @@ static inline void genl_dump_check_consistent(struct netlink_callback *cb, * @flags: netlink message flags * @cmd: generic netlink command * - * Returns pointer to user specific header + * Returns: pointer to user specific header */ static inline void *genlmsg_put_reply(struct sk_buff *skb, struct genl_info *info, @@ -292,6 +468,35 @@ static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr) } /** + * 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 @@ -304,10 +509,8 @@ 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) { - if (WARN_ON_ONCE(group >= family->n_mcgrps)) - return -EINVAL; - group = family->mcgrp_offset + group; - return nlmsg_multicast(net->genl_sock, skb, portid, group, flags); + return genlmsg_multicast_netns_filtered(family, net, skb, portid, + group, flags, NULL, NULL); } /** @@ -332,16 +535,16 @@ static inline int genlmsg_multicast(const struct genl_family *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); + 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 */ @@ -361,7 +564,7 @@ static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info) } /** - * gennlmsg_data - head of message payload + * genlmsg_data - head of message payload * @gnlh: genetlink message header */ static inline void *genlmsg_data(const struct genlmsghdr *gnlh) |