pn_netlink.c revision 660f706d931d4795d341805e083a8091af74fa88 
1/*
2 * File: pn_netlink.c
3 *
4 * Phonet netlink interface
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
9 * Original author: Sakari Ailus <sakari.ailus@nokia.com>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * version 2 as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23 * 02110-1301 USA
24 */
25
26#include <linux/kernel.h>
27#include <linux/netlink.h>
28#include <linux/phonet.h>
29#include <net/sock.h>
30#include <net/phonet/pn_dev.h>
31
32static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
33		     u32 pid, u32 seq, int event);
34
35static void rtmsg_notify(int event, struct net_device *dev, u8 addr)
36{
37	struct sk_buff *skb;
38	int err = -ENOBUFS;
39
40	skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
41			nla_total_size(1), GFP_KERNEL);
42	if (skb == NULL)
43		goto errout;
44	err = fill_addr(skb, dev, addr, 0, 0, event);
45	if (err < 0) {
46		WARN_ON(err == -EMSGSIZE);
47		kfree_skb(skb);
48		goto errout;
49	}
50	err = rtnl_notify(skb, dev_net(dev), 0,
51			  RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
52errout:
53	if (err < 0)
54		rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);
55}
56
57static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
58	[IFA_LOCAL] = { .type = NLA_U8 },
59};
60
61static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *attr)
62{
63	struct net *net = sock_net(skb->sk);
64	struct nlattr *tb[IFA_MAX+1];
65	struct net_device *dev;
66	struct ifaddrmsg *ifm;
67	int err;
68	u8 pnaddr;
69
70	if (!capable(CAP_SYS_ADMIN))
71		return -EPERM;
72
73	ASSERT_RTNL();
74
75	err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_phonet_policy);
76	if (err < 0)
77		return err;
78
79	ifm = nlmsg_data(nlh);
80	if (tb[IFA_LOCAL] == NULL)
81		return -EINVAL;
82	pnaddr = nla_get_u8(tb[IFA_LOCAL]);
83	if (pnaddr & 3)
84		/* Phonet addresses only have 6 high-order bits */
85		return -EINVAL;
86
87	dev = __dev_get_by_index(net, ifm->ifa_index);
88	if (dev == NULL)
89		return -ENODEV;
90
91	if (nlh->nlmsg_type == RTM_NEWADDR)
92		err = phonet_address_add(dev, pnaddr);
93	else
94		err = phonet_address_del(dev, pnaddr);
95	if (!err)
96		rtmsg_notify(nlh->nlmsg_type, dev, pnaddr);
97	return err;
98}
99
100static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
101			u32 pid, u32 seq, int event)
102{
103	struct ifaddrmsg *ifm;
104	struct nlmsghdr *nlh;
105
106	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*ifm), 0);
107	if (nlh == NULL)
108		return -EMSGSIZE;
109
110	ifm = nlmsg_data(nlh);
111	ifm->ifa_family = AF_PHONET;
112	ifm->ifa_prefixlen = 0;
113	ifm->ifa_flags = IFA_F_PERMANENT;
114	ifm->ifa_scope = RT_SCOPE_LINK;
115	ifm->ifa_index = dev->ifindex;
116	NLA_PUT_U8(skb, IFA_LOCAL, addr);
117	return nlmsg_end(skb, nlh);
118
119nla_put_failure:
120	nlmsg_cancel(skb, nlh);
121	return -EMSGSIZE;
122}
123
124static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
125{
126	struct net *net = sock_net(skb->sk);
127	struct phonet_device *pnd;
128	int dev_idx = 0, dev_start_idx = cb->args[0];
129	int addr_idx = 0, addr_start_idx = cb->args[1];
130
131	spin_lock_bh(&pndevs.lock);
132	list_for_each_entry(pnd, &pndevs.list, list) {
133		u8 addr;
134
135		if (!net_eq(dev_net(pnd->netdev), net))
136			continue;
137		if (dev_idx > dev_start_idx)
138			addr_start_idx = 0;
139		if (dev_idx++ < dev_start_idx)
140			continue;
141
142		addr_idx = 0;
143		for (addr = find_first_bit(pnd->addrs, 64); addr < 64;
144			addr = find_next_bit(pnd->addrs, 64, 1+addr)) {
145			if (addr_idx++ < addr_start_idx)
146				continue;
147
148			if (fill_addr(skb, pnd->netdev, addr << 2,
149					 NETLINK_CB(cb->skb).pid,
150					cb->nlh->nlmsg_seq, RTM_NEWADDR))
151				goto out;
152		}
153	}
154
155out:
156	spin_unlock_bh(&pndevs.lock);
157	cb->args[0] = dev_idx;
158	cb->args[1] = addr_idx;
159
160	return skb->len;
161}
162
163int __init phonet_netlink_register(void)
164{
165	int err = __rtnl_register(PF_PHONET, RTM_NEWADDR, addr_doit, NULL);
166	if (err)
167		return err;
168
169	/* Further __rtnl_register() cannot fail */
170	__rtnl_register(PF_PHONET, RTM_DELADDR, addr_doit, NULL);
171	__rtnl_register(PF_PHONET, RTM_GETADDR, NULL, getaddr_dumpit);
172	return 0;
173}
174