Commit eaaa3139 authored by Andrey Vagin's avatar Andrey Vagin Committed by David S. Miller
Browse files

netlink: Diag core and basic socket info dumping (v2) 



The netlink_diag can be built as a module, just like it's done in
unix sockets.

The core dumping message carries the basic info about netlink sockets:
family, type and protocol, portis, dst_group, dst_portid, state.

Groups can be received as an optional parameter NETLINK_DIAG_GROUPS.

Netlink sockets cab be filtered by protocols.

The socket inode number and cookie is reserved for future per-socket info
retrieving. The per-protocol filtering is also reserved for future by
requiring the sdiag_protocol to be zero.

The file /proc/net/netlink doesn't provide enough information for
dumping netlink sockets. It doesn't provide dst_group, dst_portid,
groups above 32.

v2: fix NETLINK_DIAG_MAX. Now it's equal to the last constant.

Acked-by: default avatarPavel Emelyanov <xemul@parallels.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarAndrey Vagin <avagin@openvz.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0f29c768

include/uapi/linux/netlink_diag.h

0 → 100644
+42 −0
Original line number Diff line number Diff line 
#ifndef __NETLINK_DIAG_H__

#define __NETLINK_DIAG_H__



#include <linux/types.h>



struct netlink_diag_req {

	__u8	sdiag_family;

	__u8	sdiag_protocol;

	__u16	pad;

	__u32	ndiag_ino;

	__u32	ndiag_show;

	__u32	ndiag_cookie[2];

};



struct netlink_diag_msg {

	__u8	ndiag_family;

	__u8	ndiag_type;

	__u8	ndiag_protocol;

	__u8	ndiag_state;



	__u32	ndiag_portid;

	__u32	ndiag_dst_portid;

	__u32	ndiag_dst_group;

	__u32	ndiag_ino;

	__u32	ndiag_cookie[2];

};



enum {

	NETLINK_DIAG_MEMINFO,

	NETLINK_DIAG_GROUPS,



	__NETLINK_DIAG_MAX,

};



#define NETLINK_DIAG_MAX (__NETLINK_DIAG_MAX - 1)



#define NDIAG_PROTO_ALL		((__u8) ~0)



#define NDIAG_SHOW_MEMINFO	0x00000001 /* show memory info of a socket */

#define NDIAG_SHOW_GROUPS	0x00000002 /* show groups of a netlink socket */



#endif

net/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -217,6 +217,7 @@ source "net/dns_resolver/Kconfig" 
source "net/batman-adv/Kconfig"

source "net/openvswitch/Kconfig"

source "net/vmw_vsock/Kconfig"

source "net/netlink/Kconfig"



config RPS

	boolean

net/netlink/Kconfig

0 → 100644
+10 −0
Original line number Diff line number Diff line 
#

# Netlink Sockets

#



config NETLINK_DIAG

	tristate "NETLINK: socket monitoring interface"

	default n

	---help---

	  Support for NETLINK socket monitoring interface used by the ss tool.

	  If unsure, say Y.

net/netlink/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -3,3 +3,6 @@ 
#



obj-y  				:= af_netlink.o genetlink.o



obj-$(CONFIG_NETLINK_DIAG)	+= netlink_diag.o

netlink_diag-y			:= diag.o

net/netlink/diag.c

0 → 100644
+188 −0
Original line number Diff line number Diff line 
#include <linux/module.h>



#include <net/sock.h>

#include <linux/netlink.h>

#include <linux/sock_diag.h>

#include <linux/netlink_diag.h>



#include "af_netlink.h"



static int sk_diag_dump_groups(struct sock *sk, struct sk_buff *nlskb)

{

	struct netlink_sock *nlk = nlk_sk(sk);



	if (nlk->groups == NULL)

		return 0;



	return nla_put(nlskb, NETLINK_DIAG_GROUPS, NLGRPSZ(nlk->ngroups),

		       nlk->groups);

}



static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,

			struct netlink_diag_req *req,

			u32 portid, u32 seq, u32 flags, int sk_ino)

{

	struct nlmsghdr *nlh;

	struct netlink_diag_msg *rep;

	struct netlink_sock *nlk = nlk_sk(sk);



	nlh = nlmsg_put(skb, portid, seq, SOCK_DIAG_BY_FAMILY, sizeof(*rep),

			flags);

	if (!nlh)

		return -EMSGSIZE;



	rep = nlmsg_data(nlh);

	rep->ndiag_family	= AF_NETLINK;

	rep->ndiag_type		= sk->sk_type;

	rep->ndiag_protocol	= sk->sk_protocol;

	rep->ndiag_state	= sk->sk_state;



	rep->ndiag_ino		= sk_ino;

	rep->ndiag_portid	= nlk->portid;

	rep->ndiag_dst_portid	= nlk->dst_portid;

	rep->ndiag_dst_group	= nlk->dst_group;

	sock_diag_save_cookie(sk, rep->ndiag_cookie);



	if ((req->ndiag_show & NDIAG_SHOW_GROUPS) &&

	    sk_diag_dump_groups(sk, skb))

		goto out_nlmsg_trim;



	if ((req->ndiag_show & NDIAG_SHOW_MEMINFO) &&

	    sock_diag_put_meminfo(sk, skb, NETLINK_DIAG_MEMINFO))

		goto out_nlmsg_trim;



	return nlmsg_end(skb, nlh);



out_nlmsg_trim:

	nlmsg_cancel(skb, nlh);

	return -EMSGSIZE;

}



static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,

				int protocol, int s_num)

{

	struct netlink_table *tbl = &nl_table[protocol];

	struct nl_portid_hash *hash = &tbl->hash;

	struct net *net = sock_net(skb->sk);

	struct netlink_diag_req *req;

	struct sock *sk;

	int ret = 0, num = 0, i;



	req = nlmsg_data(cb->nlh);



	for (i = 0; i <= hash->mask; i++) {

		sk_for_each(sk, &hash->table[i]) {

			if (!net_eq(sock_net(sk), net))

				continue;

			if (num < s_num) {

				num++;

				continue;

			}



			if (sk_diag_fill(sk, skb, req,

					 NETLINK_CB(cb->skb).portid,

					 cb->nlh->nlmsg_seq,

					 NLM_F_MULTI,

					 sock_i_ino(sk)) < 0) {

				ret = 1;

				goto done;

			}



			num++;

		}

	}



	sk_for_each_bound(sk, &tbl->mc_list) {

		if (sk_hashed(sk))

			continue;

		if (!net_eq(sock_net(sk), net))

			continue;

		if (num < s_num) {

			num++;

			continue;

		}



		if (sk_diag_fill(sk, skb, req,

				 NETLINK_CB(cb->skb).portid,

				 cb->nlh->nlmsg_seq,

				 NLM_F_MULTI,

				 sock_i_ino(sk)) < 0) {

			ret = 1;

			goto done;

		}

		num++;

	}

done:

	cb->args[0] = num;

	cb->args[1] = protocol;



	return ret;

}



static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)

{

	struct netlink_diag_req *req;

	int s_num = cb->args[0];



	req = nlmsg_data(cb->nlh);



	read_lock(&nl_table_lock);



	if (req->sdiag_protocol == NDIAG_PROTO_ALL) {

		int i;



		for (i = cb->args[1]; i < MAX_LINKS; i++) {

			if (__netlink_diag_dump(skb, cb, i, s_num))

				break;

			s_num = 0;

		}

	} else {

		if (req->sdiag_protocol >= MAX_LINKS) {

			read_unlock(&nl_table_lock);

			return -ENOENT;

		}



		__netlink_diag_dump(skb, cb, req->sdiag_protocol, s_num);

	}



	read_unlock(&nl_table_lock);



	return skb->len;

}



static int netlink_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)

{

	int hdrlen = sizeof(struct netlink_diag_req);

	struct net *net = sock_net(skb->sk);



	if (nlmsg_len(h) < hdrlen)

		return -EINVAL;



	if (h->nlmsg_flags & NLM_F_DUMP) {

		struct netlink_dump_control c = {

			.dump = netlink_diag_dump,

		};

		return netlink_dump_start(net->diag_nlsk, skb, h, &c);

	} else

		return -EOPNOTSUPP;

}



static const struct sock_diag_handler netlink_diag_handler = {

	.family = AF_NETLINK,

	.dump = netlink_diag_handler_dump,

};



static int __init netlink_diag_init(void)

{

	return sock_diag_register(&netlink_diag_handler);

}



static void __exit netlink_diag_exit(void)

{

	sock_diag_unregister(&netlink_diag_handler);

}



module_init(netlink_diag_init);

module_exit(netlink_diag_exit);

MODULE_LICENSE("GPL");

MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 16 /* AF_NETLINK */);

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