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Commit 9a4595bc authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETLINK]: Add set/getsockopt options to support more than 32 groups 



NETLINK_ADD_MEMBERSHIP/NETLINK_DROP_MEMBERSHIP are used to join/leave
groups, NETLINK_PKTINFO is used to enable nl_pktinfo control messages
for received packets to get the extended destination group number.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f7fa9b10

include/linux/netlink.h

+9 −0
Original line number Diff line number Diff line
@@ -90,6 +90,15 @@ struct nlmsgerr 
	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 {

include/linux/socket.h

+1 −0
Original line number Diff line number Diff line
@@ -272,6 +272,7 @@ struct ucred { 
#define SOL_NETBEUI	267

#define SOL_LLC		268

#define SOL_DCCP	269

#define SOL_NETLINK	270



/* IPX options */

#define IPX_TYPE	1

net/netlink/af_netlink.c

+93 −2
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ struct netlink_sock { 
};



#define NETLINK_KERNEL_SOCKET	0x1

#define NETLINK_RECV_PKTINFO	0x2



static inline struct netlink_sock *nlk_sk(struct sock *sk)

{
@@ -946,6 +947,94 @@ void netlink_set_err(struct sock *ssk, u32 pid, u32 group, int code) 
	read_unlock(&nl_table_lock);

}



static int netlink_setsockopt(struct socket *sock, int level, int optname,

                              char __user *optval, int optlen)

{

	struct sock *sk = sock->sk;

	struct netlink_sock *nlk = nlk_sk(sk);

	int val = 0, err;



	if (level != SOL_NETLINK)

		return -ENOPROTOOPT;



	if (optlen >= sizeof(int) &&

	    get_user(val, (int __user *)optval))

		return -EFAULT;



	switch (optname) {

	case NETLINK_PKTINFO:

		if (val)

			nlk->flags |= NETLINK_RECV_PKTINFO;

		else

			nlk->flags &= ~NETLINK_RECV_PKTINFO;

		err = 0;

		break;

	case NETLINK_ADD_MEMBERSHIP:

	case NETLINK_DROP_MEMBERSHIP: {

		unsigned int subscriptions;

		int old, new = optname == NETLINK_ADD_MEMBERSHIP ? 1 : 0;



		if (!netlink_capable(sock, NL_NONROOT_RECV))

			return -EPERM;

		if (!val || val - 1 >= nlk->ngroups)

			return -EINVAL;

		netlink_table_grab();

		old = test_bit(val - 1, nlk->groups);

		subscriptions = nlk->subscriptions - old + new;

		if (new)

			__set_bit(val - 1, nlk->groups);

		else

			__clear_bit(val - 1, nlk->groups);

		netlink_update_subscriptions(sk, subscriptions);

		netlink_table_ungrab();

		err = 0;

		break;

	}

	default:

		err = -ENOPROTOOPT;

	}

	return err;

}



static int netlink_getsockopt(struct socket *sock, int level, int optname,

                              char __user *optval, int __user *optlen)

{

	struct sock *sk = sock->sk;

	struct netlink_sock *nlk = nlk_sk(sk);

	int len, val, err;



	if (level != SOL_NETLINK)

		return -ENOPROTOOPT;



	if (get_user(len, optlen))

		return -EFAULT;

	if (len < 0)

		return -EINVAL;



	switch (optname) {

	case NETLINK_PKTINFO:

		if (len < sizeof(int))

			return -EINVAL;

		len = sizeof(int);

		val = nlk->flags & NETLINK_RECV_PKTINFO ? 1 : 0;

		put_user(len, optlen);

		put_user(val, optval);

		err = 0;

		break;

	default:

		err = -ENOPROTOOPT;

	}

	return err;

}



static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)

{

	struct nl_pktinfo info;



	info.group = NETLINK_CB(skb).dst_group;

	put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);

}



static inline void netlink_rcv_wake(struct sock *sk)

{

	struct netlink_sock *nlk = nlk_sk(sk);
@@ -1091,6 +1180,8 @@ static int netlink_recvmsg(struct kiocb *kiocb, struct socket *sock, 
		netlink_dump(sk);



	scm_recv(sock, msg, siocb->scm, flags);

	if (nlk->flags & NETLINK_RECV_PKTINFO)

		netlink_cmsg_recv_pktinfo(msg, skb);



out:

	netlink_rcv_wake(sk);
@@ -1465,8 +1556,8 @@ static struct proto_ops netlink_ops = { 
	.ioctl =	sock_no_ioctl,

	.listen =	sock_no_listen,

	.shutdown =	sock_no_shutdown,

	.setsockopt =	sock_no_setsockopt,

	.getsockopt =	sock_no_getsockopt,

	.setsockopt =	netlink_setsockopt,

	.getsockopt =	netlink_getsockopt,

	.sendmsg =	netlink_sendmsg,

	.recvmsg =	netlink_recvmsg,

	.mmap =		sock_no_mmap,