Commit eb328111 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

[GENL]: Provide more information to userspace about registered genl families 



Additionaly exports the following information when providing
the list of registered generic netlink families:
  - protocol version
  - header size
  - maximum number of attributes
  - list of available operations including
      - id
      - flags
      - avaiability of policy and doit/dumpit function

libnl HEAD provides a utility to read this new information:

	0x0010 nlctrl version 1
	    hdrsize 0 maxattr 6
	      op GETFAMILY (0x03) [POLICY,DOIT,DUMPIT]
	0x0011 NLBL_MGMT version 1
	    hdrsize 0 maxattr 0
	      op unknown (0x02) [DOIT]
	      op unknown (0x03) [DOIT]
	      ....

Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 78e5b891

include/linux/genetlink.h

+18 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ struct genlmsghdr { 


#define GENL_HDRLEN	NLMSG_ALIGN(sizeof(struct genlmsghdr))



#define GENL_ADMIN_PERM		0x01



/*

 * List of reserved static generic netlink identifiers:

 */
@@ -43,9 +45,25 @@ enum { 
	CTRL_ATTR_UNSPEC,

	CTRL_ATTR_FAMILY_ID,

	CTRL_ATTR_FAMILY_NAME,

	CTRL_ATTR_VERSION,

	CTRL_ATTR_HDRSIZE,

	CTRL_ATTR_MAXATTR,

	CTRL_ATTR_OPS,

	__CTRL_ATTR_MAX,

};



#define CTRL_ATTR_MAX (__CTRL_ATTR_MAX - 1)



enum {

	CTRL_ATTR_OP_UNSPEC,

	CTRL_ATTR_OP_ID,

	CTRL_ATTR_OP_FLAGS,

	CTRL_ATTR_OP_POLICY,

	CTRL_ATTR_OP_DOIT,

	CTRL_ATTR_OP_DUMPIT,

	__CTRL_ATTR_OP_MAX,

};



#define CTRL_ATTR_OP_MAX (__CTRL_ATTR_OP_MAX - 1)



#endif	/* __LINUX_GENERIC_NETLINK_H */

include/net/genetlink.h

+0 −2
Original line number Diff line number Diff line
@@ -27,8 +27,6 @@ struct genl_family 
	struct list_head	family_list;	/* private */

};



#define GENL_ADMIN_PERM		0x01



/**

 * struct genl_info - receiving information

 * @snd_seq: sending sequence number

net/netlink/genetlink.c

+40 −0
Original line number Diff line number Diff line
@@ -387,7 +387,10 @@ static void genl_rcv(struct sock *sk, int len) 
static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,

			  u32 flags, struct sk_buff *skb, u8 cmd)

{

	struct nlattr *nla_ops;

	struct genl_ops *ops;

	void *hdr;

	int idx = 1;



	hdr = genlmsg_put(skb, pid, seq, GENL_ID_CTRL, 0, flags, cmd,

			  family->version);
@@ -396,6 +399,37 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq, 


	NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, family->name);

	NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, family->id);

	NLA_PUT_U32(skb, CTRL_ATTR_VERSION, family->version);

	NLA_PUT_U32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize);

	NLA_PUT_U32(skb, CTRL_ATTR_MAXATTR, family->maxattr);



	nla_ops = nla_nest_start(skb, CTRL_ATTR_OPS);

	if (nla_ops == NULL)

		goto nla_put_failure;



	list_for_each_entry(ops, &family->ops_list, ops_list) {

		struct nlattr *nest;



		nest = nla_nest_start(skb, idx++);

		if (nest == NULL)

			goto nla_put_failure;



		NLA_PUT_U32(skb, CTRL_ATTR_OP_ID, ops->cmd);

		NLA_PUT_U32(skb, CTRL_ATTR_OP_FLAGS, ops->flags);



		if (ops->policy)

			NLA_PUT_FLAG(skb, CTRL_ATTR_OP_POLICY);



		if (ops->doit)

			NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DOIT);



		if (ops->dumpit)

			NLA_PUT_FLAG(skb, CTRL_ATTR_OP_DUMPIT);



		nla_nest_end(skb, nest);

	}



	nla_nest_end(skb, nla_ops);



	return genlmsg_end(skb, hdr);
@@ -411,6 +445,9 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 
	int chains_to_skip = cb->args[0];

	int fams_to_skip = cb->args[1];



	if (chains_to_skip != 0)

		genl_lock();



	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {

		if (i < chains_to_skip)

			continue;
@@ -428,6 +465,9 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb) 
	}



errout:

	if (chains_to_skip != 0)

		genl_unlock();



	cb->args[0] = i;

	cb->args[1] = n;

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