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android_kernel_xiaomi_sm8350/include/linux/netlink.h
Evgeniy Polyakov 7672d0b544 [NET]: Add netlink connector. 
Kernel connector - new userspace <-> kernel space easy to use
communication module which implements easy to use bidirectional
message bus using netlink as it's backend.  Connector was created to
eliminate complex skb handling both in send and receive message bus
direction.

Connector driver adds possibility to connect various agents using as
one of it's backends netlink based network.  One must register
callback and identifier. When driver receives special netlink message
with appropriate identifier, appropriate callback will be called.

From the userspace point of view it's quite straightforward:

	socket();
	bind();
	send();
	recv();

But if kernelspace want to use full power of such connections, driver
writer must create special sockets, must know about struct sk_buff
handling...  Connector allows any kernelspace agents to use netlink
based networking for inter-process communication in a significantly
easier way:

int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *));
void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask);

struct cb_id
{
	__u32			idx;
	__u32			val;
};

idx and val are unique identifiers which must be registered in
connector.h for in-kernel usage.  void (*callback) (void *) - is a
callback function which will be called when message with above idx.val
will be received by connector core.

Using connector completely hides low-level transport layer from it's
users.

Connector uses new netlink ability to have many groups in one socket.

[ Incorporating many cleanups and fixes by myself and
  Andrew Morton -DaveM ]

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-11 19:15:07 -07:00

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#ifndef __LINUX_NETLINK_H
#define __LINUX_NETLINK_H
#include <linux/socket.h> /* for sa_family_t */
#include <linux/types.h>
#define NETLINK_ROUTE 0 /* Routing/device hook */
#define NETLINK_W1 1 /* 1-wire subsystem */
#define NETLINK_USERSOCK 2 /* Reserved for user mode socket protocols */
#define NETLINK_FIREWALL 3 /* Firewalling hook */
#define NETLINK_INET_DIAG 4 /* INET socket monitoring */
#define NETLINK_NFLOG 5 /* netfilter/iptables ULOG */
#define NETLINK_XFRM 6 /* ipsec */
#define NETLINK_SELINUX 7 /* SELinux event notifications */
#define NETLINK_ISCSI 8 /* Open-iSCSI */
#define NETLINK_AUDIT 9 /* auditing */
#define NETLINK_FIB_LOOKUP 10
#define NETLINK_CONNECTOR 11
#define NETLINK_NETFILTER 12 /* netfilter subsystem */
#define NETLINK_IP6_FW 13
#define NETLINK_DNRTMSG 14 /* DECnet routing messages */
#define NETLINK_KOBJECT_UEVENT 15 /* Kernel messages to userspace */
#define MAX_LINKS 32
struct sockaddr_nl
{
sa_family_t nl_family; /* AF_NETLINK */
unsigned short nl_pad; /* zero */
__u32 nl_pid; /* process pid */
__u32 nl_groups; /* multicast groups mask */
};
struct nlmsghdr
{
__u32 nlmsg_len; /* Length of message including header */
__u16 nlmsg_type; /* Message content */
__u16 nlmsg_flags; /* Additional flags */
__u32 nlmsg_seq; /* Sequence number */
__u32 nlmsg_pid; /* Sending process PID */
};
/* Flags values */
#define NLM_F_REQUEST 1 /* It is request message. */
#define NLM_F_MULTI 2 /* Multipart message, terminated by NLMSG_DONE */
#define NLM_F_ACK 4 /* Reply with ack, with zero or error code */
#define NLM_F_ECHO 8 /* Echo this request */
/* Modifiers to GET request */
#define NLM_F_ROOT 0x100 /* specify tree root */
#define NLM_F_MATCH 0x200 /* return all matching */
#define NLM_F_ATOMIC 0x400 /* atomic GET */
#define NLM_F_DUMP (NLM_F_ROOT|NLM_F_MATCH)
/* Modifiers to NEW request */
#define NLM_F_REPLACE 0x100 /* Override existing */
#define NLM_F_EXCL 0x200 /* Do not touch, if it exists */
#define NLM_F_CREATE 0x400 /* Create, if it does not exist */
#define NLM_F_APPEND 0x800 /* Add to end of list */
/*
4.4BSD ADD NLM_F_CREATE|NLM_F_EXCL
4.4BSD CHANGE NLM_F_REPLACE
True CHANGE NLM_F_CREATE|NLM_F_REPLACE
Append NLM_F_CREATE
Check NLM_F_EXCL
*/
#define NLMSG_ALIGNTO 4
#define NLMSG_ALIGN(len) ( ((len)+NLMSG_ALIGNTO-1) & ~(NLMSG_ALIGNTO-1) )
#define NLMSG_LENGTH(len) ((len)+NLMSG_ALIGN(sizeof(struct nlmsghdr)))
#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(len))
#define NLMSG_DATA(nlh) ((void*)(((char*)nlh) + NLMSG_LENGTH(0)))
#define NLMSG_NEXT(nlh,len) ((len) -= NLMSG_ALIGN((nlh)->nlmsg_len), \
(struct nlmsghdr*)(((char*)(nlh)) + NLMSG_ALIGN((nlh)->nlmsg_len)))
#define NLMSG_OK(nlh,len) ((len) >= (int)sizeof(struct nlmsghdr) && \
(nlh)->nlmsg_len >= sizeof(struct nlmsghdr) && \
(nlh)->nlmsg_len <= (len))
#define NLMSG_PAYLOAD(nlh,len) ((nlh)->nlmsg_len - NLMSG_SPACE((len)))
#define NLMSG_NOOP 0x1 /* Nothing. */
#define NLMSG_ERROR 0x2 /* Error */
#define NLMSG_DONE 0x3 /* End of a dump */
#define NLMSG_OVERRUN 0x4 /* Data lost */
struct nlmsgerr
{
int error;
struct nlmsghdr msg;
};
#define NETLINK_ADD_MEMBERSHIP 1
#define NETLINK_DROP_MEMBERSHIP 2
#define NETLINK_PKTINFO 3
struct nl_pktinfo
{
__u32 group;
};
#define NET_MAJOR 36 /* Major 36 is reserved for networking */
enum {
NETLINK_UNCONNECTED = 0,
NETLINK_CONNECTED,
};
#ifdef __KERNEL__
#include <linux/capability.h>
#include <linux/skbuff.h>
struct netlink_skb_parms
{
struct ucred creds; /* Skb credentials */
__u32 pid;
__u32 dst_pid;
__u32 dst_group;
kernel_cap_t eff_cap;
__u32 loginuid; /* Login (audit) uid */
};
#define NETLINK_CB(skb) (*(struct netlink_skb_parms*)&((skb)->cb))
#define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds)
extern struct sock *netlink_kernel_create(int unit, unsigned int groups, void (*input)(struct sock *sk, int len), struct module *module);
extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 pid, int nonblock);
extern int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 pid,
__u32 group, unsigned int __nocast allocation);
extern void netlink_set_err(struct sock *ssk, __u32 pid, __u32 group, int code);
extern int netlink_register_notifier(struct notifier_block *nb);
extern int netlink_unregister_notifier(struct notifier_block *nb);
/* finegrained unicast helpers: */
struct sock *netlink_getsockbyfilp(struct file *filp);
int netlink_attachskb(struct sock *sk, struct sk_buff *skb, int nonblock, long timeo);
void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
int netlink_sendskb(struct sock *sk, struct sk_buff *skb, int protocol);
/*
* skb should fit one page. This choice is good for headerless malloc.
*/
#define NLMSG_GOODORDER 0
#define NLMSG_GOODSIZE (SKB_MAX_ORDER(0, NLMSG_GOODORDER))
struct netlink_callback
{
struct sk_buff *skb;
struct nlmsghdr *nlh;
int (*dump)(struct sk_buff * skb, struct netlink_callback *cb);
int (*done)(struct netlink_callback *cb);
int family;
long args[5];
};
struct netlink_notify
{
int pid;
int protocol;
};
static __inline__ struct nlmsghdr *
__nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags)
{
struct nlmsghdr *nlh;
int size = NLMSG_LENGTH(len);
nlh = (struct nlmsghdr*)skb_put(skb, NLMSG_ALIGN(size));
nlh->nlmsg_type = type;
nlh->nlmsg_len = size;
nlh->nlmsg_flags = flags;
nlh->nlmsg_pid = pid;
nlh->nlmsg_seq = seq;
memset(NLMSG_DATA(nlh) + len, 0, NLMSG_ALIGN(size) - size);
return nlh;
}
#define NLMSG_NEW(skb, pid, seq, type, len, flags) \
({ if (skb_tailroom(skb) < (int)NLMSG_SPACE(len)) \
goto nlmsg_failure; \
__nlmsg_put(skb, pid, seq, type, len, flags); })
#define NLMSG_PUT(skb, pid, seq, type, len) \
NLMSG_NEW(skb, pid, seq, type, len, 0)
#define NLMSG_NEW_ANSWER(skb, cb, type, len, flags) \
NLMSG_NEW(skb, NETLINK_CB((cb)->skb).pid, \
(cb)->nlh->nlmsg_seq, type, len, flags)
#define NLMSG_END(skb, nlh) \
({ (nlh)->nlmsg_len = (skb)->tail - (unsigned char *) (nlh); \
(skb)->len; })
#define NLMSG_CANCEL(skb, nlh) \
({ skb_trim(skb, (unsigned char *) (nlh) - (skb)->data); \
-1; })
extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
struct nlmsghdr *nlh,
int (*dump)(struct sk_buff *skb, struct netlink_callback*),
int (*done)(struct netlink_callback*));
#define NL_NONROOT_RECV 0x1
#define NL_NONROOT_SEND 0x2
extern void netlink_set_nonroot(int protocol, unsigned flag);
#endif /* __KERNEL__ */
#endif /* __LINUX_NETLINK_H */
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