diff options
Diffstat (limited to 'include/net/genetlink.h')
| -rw-r--r-- | include/net/genetlink.h | 430 |
1 files changed, 430 insertions, 0 deletions
diff --git a/include/net/genetlink.h b/include/net/genetlink.h new file mode 100644 index 000000000..a9af1cc8c --- /dev/null +++ b/include/net/genetlink.h @@ -0,0 +1,430 @@ +#ifndef __NET_GENERIC_NETLINK_H +#define __NET_GENERIC_NETLINK_H + +#include <linux/genetlink.h> +#include <net/netlink.h> +#include <net/net_namespace.h> + +#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN) + +/** + * struct genl_multicast_group - generic netlink multicast group + * @name: name of the multicast group, names are per-family + */ +struct genl_multicast_group { + char name[GENL_NAMSIZ]; +}; + +struct genl_ops; +struct genl_info; + +/** + * struct genl_family - generic netlink family + * @id: protocol family idenfitier + * @hdrsize: length of user specific header in bytes + * @name: name of family + * @version: protocol version + * @maxattr: maximum number of attributes supported + * @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 + * @mcast_bind: a socket bound to the given multicast group (which + * is given as the offset into the groups array) + * @mcast_unbind: a socket was unbound from the given multicast group. + * Note that unbind() will not be called symmetrically if the + * generic netlink family is removed while there are still open + * sockets. + * @attrbuf: buffer to store parsed attributes + * @family_list: family list + * @mcgrps: multicast groups used by this family (private) + * @n_mcgrps: number of multicast groups (private) + * @mcgrp_offset: starting number of multicast group IDs in this family + * @ops: the operations supported by this family (private) + * @n_ops: number of operations supported by this family (private) + */ +struct genl_family { + unsigned int id; + unsigned int hdrsize; + char name[GENL_NAMSIZ]; + unsigned int version; + unsigned int maxattr; + bool netnsok; + bool parallel_ops; + int (*pre_doit)(const struct genl_ops *ops, + struct sk_buff *skb, + struct genl_info *info); + void (*post_doit)(const struct genl_ops *ops, + struct sk_buff *skb, + struct genl_info *info); + int (*mcast_bind)(struct net *net, int group); + void (*mcast_unbind)(struct net *net, int group); + struct nlattr ** attrbuf; /* private */ + const struct genl_ops * ops; /* private */ + const struct genl_multicast_group *mcgrps; /* private */ + unsigned int n_ops; /* private */ + unsigned int n_mcgrps; /* private */ + unsigned int mcgrp_offset; /* private */ + struct list_head family_list; /* private */ + struct module *module; +}; + +/** + * struct genl_info - receiving information + * @snd_seq: sending sequence number + * @snd_portid: netlink portid of sender + * @nlhdr: netlink message header + * @genlhdr: generic netlink message header + * @userhdr: user specific header + * @attrs: netlink attributes + * @_net: network namespace + * @user_ptr: user pointers + * @dst_sk: destination socket + */ +struct genl_info { + u32 snd_seq; + u32 snd_portid; + struct nlmsghdr * nlhdr; + struct genlmsghdr * genlhdr; + void * userhdr; + struct nlattr ** attrs; + possible_net_t _net; + void * user_ptr[2]; + struct sock * dst_sk; +}; + +static inline struct net *genl_info_net(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); +} + +/** + * struct genl_ops - generic netlink operations + * @cmd: command identifier + * @internal_flags: flags used by the family + * @flags: flags + * @policy: attribute validation policy + * @doit: standard command callback + * @dumpit: callback for dumpers + * @done: completion callback for dumps + * @ops_list: operations list + */ +struct genl_ops { + const struct nla_policy *policy; + int (*doit)(struct sk_buff *skb, + struct genl_info *info); + int (*dumpit)(struct sk_buff *skb, + struct netlink_callback *cb); + int (*done)(struct netlink_callback *cb); + u8 cmd; + u8 internal_flags; + u8 flags; +}; + +int __genl_register_family(struct genl_family *family); + +static inline int genl_register_family(struct genl_family *family) +{ + family->module = THIS_MODULE; + return __genl_register_family(family); +} + +/** + * genl_register_family_with_ops - register a generic netlink family with ops + * @family: generic netlink family + * @ops: operations to be registered + * @n_ops: number of elements to register + * + * Registers the specified family and operations from the specified table. + * Only one family may be registered with the same family name or identifier. + * + * The family id may equal GENL_ID_GENERATE causing an unique id to + * be automatically generated and assigned. + * + * Either a doit or dumpit callback must be specified for every registered + * operation or the function will fail. Only one operation structure per + * command identifier may be registered. + * + * See include/net/genetlink.h for more documenation on the operations + * structure. + * + * Return 0 on success or a negative error code. + */ +static inline int +_genl_register_family_with_ops_grps(struct genl_family *family, + const struct genl_ops *ops, size_t n_ops, + const struct genl_multicast_group *mcgrps, + size_t n_mcgrps) +{ + family->module = THIS_MODULE; + family->ops = ops; + family->n_ops = n_ops; + family->mcgrps = mcgrps; + family->n_mcgrps = n_mcgrps; + return __genl_register_family(family); +} + +#define genl_register_family_with_ops(family, ops) \ + _genl_register_family_with_ops_grps((family), \ + (ops), ARRAY_SIZE(ops), \ + NULL, 0) +#define genl_register_family_with_ops_groups(family, ops, grps) \ + _genl_register_family_with_ops_grps((family), \ + (ops), ARRAY_SIZE(ops), \ + (grps), ARRAY_SIZE(grps)) + +int genl_unregister_family(struct genl_family *family); +void genl_notify(struct genl_family *family, + struct sk_buff *skb, struct net *net, u32 portid, + u32 group, struct nlmsghdr *nlh, gfp_t flags); + +struct sk_buff *genlmsg_new_unicast(size_t payload, struct genl_info *info, + gfp_t flags); +void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, + struct genl_family *family, int flags, u8 cmd); + +/** + * genlmsg_nlhdr - Obtain netlink header from user specified header + * @user_hdr: user header as returned from genlmsg_put() + * @family: generic netlink family + * + * Returns pointer to netlink header. + */ +static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr, + struct genl_family *family) +{ + return (struct nlmsghdr *)((char *)user_hdr - + family->hdrsize - + GENL_HDRLEN - + NLMSG_HDRLEN); +} + +/** + * 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 + * */ +static inline int genlmsg_parse(const struct nlmsghdr *nlh, + const struct genl_family *family, + struct nlattr *tb[], int maxtype, + const struct nla_policy *policy) +{ + return nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype, + policy); +} + +/** + * 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() + * @family: generic netlink family + * + * 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, + struct genl_family *family) +{ + nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family)); +} + +/** + * 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, + 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 - 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(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); +} + +/** + * 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(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(struct genl_family *family, + struct sk_buff *skb, u32 portid, + unsigned int group, gfp_t flags); + +/** + * genlmsg_unicast - unicast a netlink message + * @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); +} + +/** + * gennlmsg_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(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(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 */ |