pn_netlink.c

/*
 * File: pn_netlink.c
 *
 * Phonet netlink interface
 *
 * Copyright (C) 2008 Nokia Corporation.
 *
 * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
 * Original author: Sakari Ailus <sakari.ailus@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/kernel.h>
#include <linux/netlink.h>
#include <linux/phonet.h>
#include <net/sock.h>
#include <net/phonet/pn_dev.h>

static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
		     u32 pid, u32 seq, int event);

static void rtmsg_notify(int event, struct net_device *dev, u8 addr)
{
	struct sk_buff *skb;
	int err = -ENOBUFS;

	skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
			nla_total_size(1), GFP_KERNEL);
	if (skb == NULL)
		goto errout;
	err = fill_addr(skb, dev, addr, 0, 0, event);
	if (err < 0) {
		WARN_ON(err == -EMSGSIZE);
		kfree_skb(skb);
		goto errout;
	}
	err = rtnl_notify(skb, dev_net(dev), 0,
			  RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
errout:
	if (err < 0)
		rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);
}

static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
	[IFA_LOCAL] = { .type = NLA_U8 },
};

static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *attr)
{
	struct net *net = sock_net(skb->sk);
	struct nlattr *tb[IFA_MAX+1];
	struct net_device *dev;
	struct ifaddrmsg *ifm;
	int err;
	u8 pnaddr;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	ASSERT_RTNL();

	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_phonet_policy);
	if (err < 0)
		return err;

	ifm = nlmsg_data(nlh);
	if (tb[IFA_LOCAL] == NULL)
		return -EINVAL;
	pnaddr = nla_get_u8(tb[IFA_LOCAL]);
	if (pnaddr & 3)
		/* Phonet addresses only have 6 high-order bits */
		return -EINVAL;

	dev = __dev_get_by_index(net, ifm->ifa_index);
	if (dev == NULL)
		return -ENODEV;

	if (nlh->nlmsg_type == RTM_NEWADDR)
		err = phonet_address_add(dev, pnaddr);
	else
		err = phonet_address_del(dev, pnaddr);
	if (!err)
		rtmsg_notify(nlh->nlmsg_type, dev, pnaddr);
	return err;
}

static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
			u32 pid, u32 seq, int event)
{
	struct ifaddrmsg *ifm;
	struct nlmsghdr *nlh;

	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*ifm), 0);
	if (nlh == NULL)
		return -EMSGSIZE;

	ifm = nlmsg_data(nlh);
	ifm->ifa_family = AF_PHONET;
	ifm->ifa_prefixlen = 0;
	ifm->ifa_flags = IFA_F_PERMANENT;
	ifm->ifa_scope = RT_SCOPE_LINK;
	ifm->ifa_index = dev->ifindex;
	NLA_PUT_U8(skb, IFA_LOCAL, addr);
	return nlmsg_end(skb, nlh);

nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return -EMSGSIZE;
}

static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct phonet_device *pnd;
	int dev_idx = 0, dev_start_idx = cb->args[0];
	int addr_idx = 0, addr_start_idx = cb->args[1];

	spin_lock_bh(&pndevs.lock);
	list_for_each_entry(pnd, &pndevs.list, list) {
		u8 addr;

		if (dev_idx > dev_start_idx)
			addr_start_idx = 0;
		if (dev_idx++ < dev_start_idx)
			continue;

		addr_idx = 0;
		for (addr = find_first_bit(pnd->addrs, 64); addr < 64;
			addr = find_next_bit(pnd->addrs, 64, 1+addr)) {
			if (addr_idx++ < addr_start_idx)
				continue;

			if (fill_addr(skb, pnd->netdev, addr << 2,
					 NETLINK_CB(cb->skb).pid,
					cb->nlh->nlmsg_seq, RTM_NEWADDR))
				goto out;
		}
	}

out:
	spin_unlock_bh(&pndevs.lock);
	cb->args[0] = dev_idx;
	cb->args[1] = addr_idx;

	return skb->len;
}

void __init phonet_netlink_register(void)
{
	rtnl_register(PF_PHONET, RTM_NEWADDR, addr_doit, NULL);
	rtnl_register(PF_PHONET, RTM_DELADDR, addr_doit, NULL);
	rtnl_register(PF_PHONET, RTM_GETADDR, NULL, getaddr_dumpit);
}