482a8524f8
The generic netlink family builds on top of netlink and provides simplifies access for the less demanding netlink users. It solves the problem of protocol numbers running out by introducing a so called controller taking care of id management and name resolving. Generic netlink modules register themself after filling out their id card (struct genl_family), after successful registration the modules are able to register callbacks to command numbers by filling out a struct genl_ops and calling genl_register_op(). The registered callbacks are invoked with attributes parsed making life of simple modules a lot easier. Although generic netlink modules can request static identifiers, it is recommended to use GENL_ID_GENERATE and to let the controller assign a unique identifier to the module. Userspace applications will then ask the controller and lookup the idenfier by the module name. Due to the current multicast implementation of netlink, the number of generic netlink modules is restricted to 1024 to avoid wasting memory for the per socket multiacst subscription bitmask. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
52 lines
1,017 B
C
52 lines
1,017 B
C
#ifndef __LINUX_GENERIC_NETLINK_H
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#define __LINUX_GENERIC_NETLINK_H
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#include <linux/netlink.h>
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#define GENL_NAMSIZ 16 /* length of family name */
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#define GENL_MIN_ID NLMSG_MIN_TYPE
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#define GENL_MAX_ID 1023
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struct genlmsghdr {
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__u8 cmd;
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__u8 version;
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__u16 reserved;
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};
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#define GENL_HDRLEN NLMSG_ALIGN(sizeof(struct genlmsghdr))
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/*
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* List of reserved static generic netlink identifiers:
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*/
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#define GENL_ID_GENERATE 0
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#define GENL_ID_CTRL NLMSG_MIN_TYPE
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/**************************************************************************
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* Controller
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**************************************************************************/
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enum {
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CTRL_CMD_UNSPEC,
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CTRL_CMD_NEWFAMILY,
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CTRL_CMD_DELFAMILY,
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CTRL_CMD_GETFAMILY,
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CTRL_CMD_NEWOPS,
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CTRL_CMD_DELOPS,
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CTRL_CMD_GETOPS,
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__CTRL_CMD_MAX,
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};
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#define CTRL_CMD_MAX (__CTRL_CMD_MAX - 1)
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enum {
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CTRL_ATTR_UNSPEC,
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CTRL_ATTR_FAMILY_ID,
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CTRL_ATTR_FAMILY_NAME,
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__CTRL_ATTR_MAX,
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};
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#define CTRL_ATTR_MAX (__CTRL_ATTR_MAX - 1)
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#endif /* __LINUX_GENERIC_NETLINK_H */
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