pn_netlink.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * File: pn_netlink.c
  4 *
  5 * Phonet netlink interface
  6 *
  7 * Copyright (C) 2008 Nokia Corporation.
  8 *
  9 * Authors: Sakari Ailus <sakari.ailus@nokia.com>
 10 *          Remi Denis-Courmont
 11 */
 12
 13#include <linux/kernel.h>
 14#include <linux/netlink.h>
 15#include <linux/phonet.h>
 16#include <linux/slab.h>
 17#include <net/sock.h>
 18#include <net/phonet/pn_dev.h>
 19
 20/* Device address handling */
 21
 22static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr,
 23		     u32 portid, u32 seq, int event);
 24
 25void phonet_address_notify(struct net *net, int event, u32 ifindex, u8 addr)
 26{
 27	struct sk_buff *skb;
 28	int err = -ENOBUFS;
 29
 30	skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
 31			nla_total_size(1), GFP_KERNEL);
 32	if (skb == NULL)
 33		goto errout;
 34
 35	err = fill_addr(skb, ifindex, addr, 0, 0, event);
 36	if (err < 0) {
 37		WARN_ON(err == -EMSGSIZE);
 38		kfree_skb(skb);
 39		goto errout;
 40	}
 41
 42	rtnl_notify(skb, net, 0, RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
 43	return;
 44errout:
 45	rtnl_set_sk_err(net, RTNLGRP_PHONET_IFADDR, err);
 46}
 47
 48static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
 49	[IFA_LOCAL] = { .type = NLA_U8 },
 50};
 51
 52static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
 53		     struct netlink_ext_ack *extack)
 54{
 55	struct net *net = sock_net(skb->sk);
 56	struct nlattr *tb[IFA_MAX+1];
 57	struct net_device *dev;
 58	struct ifaddrmsg *ifm;
 59	int err;
 60	u8 pnaddr;
 61
 62	if (!netlink_capable(skb, CAP_NET_ADMIN))
 63		return -EPERM;
 64
 65	if (!netlink_capable(skb, CAP_SYS_ADMIN))
 66		return -EPERM;
 67
 68	err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
 69				     ifa_phonet_policy, extack);
 70	if (err < 0)
 71		return err;
 72
 73	ifm = nlmsg_data(nlh);
 74	if (tb[IFA_LOCAL] == NULL)
 75		return -EINVAL;
 76	pnaddr = nla_get_u8(tb[IFA_LOCAL]);
 77	if (pnaddr & 3)
 78		/* Phonet addresses only have 6 high-order bits */
 79		return -EINVAL;
 80
 81	rcu_read_lock();
 82
 83	dev = dev_get_by_index_rcu(net, ifm->ifa_index);
 84	if (!dev) {
 85		rcu_read_unlock();
 86		return -ENODEV;
 87	}
 88
 89	if (nlh->nlmsg_type == RTM_NEWADDR)
 90		err = phonet_address_add(dev, pnaddr);
 91	else
 92		err = phonet_address_del(dev, pnaddr);
 93
 94	rcu_read_unlock();
 95
 96	if (!err)
 97		phonet_address_notify(net, nlh->nlmsg_type, ifm->ifa_index, pnaddr);
 98
 99	return err;
100}
101
102static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr,
103		     u32 portid, u32 seq, int event)
104{
105	struct ifaddrmsg *ifm;
106	struct nlmsghdr *nlh;
107
108	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), 0);
109	if (nlh == NULL)
110		return -EMSGSIZE;
111
112	ifm = nlmsg_data(nlh);
113	ifm->ifa_family = AF_PHONET;
114	ifm->ifa_prefixlen = 0;
115	ifm->ifa_flags = IFA_F_PERMANENT;
116	ifm->ifa_scope = RT_SCOPE_LINK;
117	ifm->ifa_index = ifindex;
118	if (nla_put_u8(skb, IFA_LOCAL, addr))
119		goto nla_put_failure;
120	nlmsg_end(skb, nlh);
121	return 0;
122
123nla_put_failure:
124	nlmsg_cancel(skb, nlh);
125	return -EMSGSIZE;
126}
127
128static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
129{
130	int addr_idx = 0, addr_start_idx = cb->args[1];
131	int dev_idx = 0, dev_start_idx = cb->args[0];
132	struct phonet_device_list *pndevs;
133	struct phonet_device *pnd;
134	int err = 0;
135
136	pndevs = phonet_device_list(sock_net(skb->sk));
137
138	rcu_read_lock();
139	list_for_each_entry_rcu(pnd, &pndevs->list, list) {
140		DECLARE_BITMAP(addrs, 64);
141		u8 addr;
142
143		if (dev_idx > dev_start_idx)
144			addr_start_idx = 0;
145		if (dev_idx++ < dev_start_idx)
146			continue;
147
148		addr_idx = 0;
149		memcpy(addrs, pnd->addrs, sizeof(pnd->addrs));
150
151		for_each_set_bit(addr, addrs, 64) {
152			if (addr_idx++ < addr_start_idx)
153				continue;
154
155			err = fill_addr(skb, READ_ONCE(pnd->netdev->ifindex),
156					addr << 2, NETLINK_CB(cb->skb).portid,
157					cb->nlh->nlmsg_seq, RTM_NEWADDR);
158			if (err < 0)
159				goto out;
160		}
161	}
162out:
163	rcu_read_unlock();
164
165	cb->args[0] = dev_idx;
166	cb->args[1] = addr_idx;
167
168	return err;
169}
170
171/* Routes handling */
172
173static int fill_route(struct sk_buff *skb, u32 ifindex, u8 dst,
174		      u32 portid, u32 seq, int event)
175{
176	struct rtmsg *rtm;
177	struct nlmsghdr *nlh;
178
179	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), 0);
180	if (nlh == NULL)
181		return -EMSGSIZE;
182
183	rtm = nlmsg_data(nlh);
184	rtm->rtm_family = AF_PHONET;
185	rtm->rtm_dst_len = 6;
186	rtm->rtm_src_len = 0;
187	rtm->rtm_tos = 0;
188	rtm->rtm_table = RT_TABLE_MAIN;
189	rtm->rtm_protocol = RTPROT_STATIC;
190	rtm->rtm_scope = RT_SCOPE_UNIVERSE;
191	rtm->rtm_type = RTN_UNICAST;
192	rtm->rtm_flags = 0;
193	if (nla_put_u8(skb, RTA_DST, dst) || nla_put_u32(skb, RTA_OIF, ifindex))
194		goto nla_put_failure;
195	nlmsg_end(skb, nlh);
196	return 0;
197
198nla_put_failure:
199	nlmsg_cancel(skb, nlh);
200	return -EMSGSIZE;
201}
202
203void rtm_phonet_notify(struct net *net, int event, u32 ifindex, u8 dst)
204{
205	struct sk_buff *skb;
206	int err = -ENOBUFS;
207
208	skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct rtmsg)) +
209			nla_total_size(1) + nla_total_size(4), GFP_KERNEL);
210	if (skb == NULL)
211		goto errout;
212
213	err = fill_route(skb, ifindex, dst, 0, 0, event);
214	if (err < 0) {
215		WARN_ON(err == -EMSGSIZE);
216		kfree_skb(skb);
217		goto errout;
218	}
219
220	rtnl_notify(skb, net, 0, RTNLGRP_PHONET_ROUTE, NULL, GFP_KERNEL);
221	return;
222errout:
223	rtnl_set_sk_err(net, RTNLGRP_PHONET_ROUTE, err);
224}
225
226static const struct nla_policy rtm_phonet_policy[RTA_MAX+1] = {
227	[RTA_DST] = { .type = NLA_U8 },
228	[RTA_OIF] = { .type = NLA_U32 },
229};
230
231static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
232		      struct netlink_ext_ack *extack)
233{
234	struct net *net = sock_net(skb->sk);
235	struct nlattr *tb[RTA_MAX+1];
236	bool sync_needed = false;
237	struct net_device *dev;
238	struct rtmsg *rtm;
239	u32 ifindex;
240	int err;
241	u8 dst;
242
243	if (!netlink_capable(skb, CAP_NET_ADMIN))
244		return -EPERM;
245
246	if (!netlink_capable(skb, CAP_SYS_ADMIN))
247		return -EPERM;
248
249	err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
250				     rtm_phonet_policy, extack);
251	if (err < 0)
252		return err;
253
254	rtm = nlmsg_data(nlh);
255	if (rtm->rtm_table != RT_TABLE_MAIN || rtm->rtm_type != RTN_UNICAST)
256		return -EINVAL;
257	if (tb[RTA_DST] == NULL || tb[RTA_OIF] == NULL)
258		return -EINVAL;
259	dst = nla_get_u8(tb[RTA_DST]);
260	if (dst & 3) /* Phonet addresses only have 6 high-order bits */
261		return -EINVAL;
262
263	ifindex = nla_get_u32(tb[RTA_OIF]);
264
265	rcu_read_lock();
266
267	dev = dev_get_by_index_rcu(net, ifindex);
268	if (!dev) {
269		rcu_read_unlock();
270		return -ENODEV;
271	}
272
273	if (nlh->nlmsg_type == RTM_NEWROUTE) {
274		err = phonet_route_add(dev, dst);
275	} else {
276		err = phonet_route_del(dev, dst);
277		if (!err)
278			sync_needed = true;
279	}
280
281	rcu_read_unlock();
282
283	if (sync_needed) {
284		synchronize_rcu();
285		dev_put(dev);
286	}
287	if (!err)
288		rtm_phonet_notify(net, nlh->nlmsg_type, ifindex, dst);
289
290	return err;
291}
292
293static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
294{
295	struct net *net = sock_net(skb->sk);
296	int err = 0;
297	u8 addr;
298
299	rcu_read_lock();
300	for (addr = cb->args[0]; addr < 64; addr++) {
301		struct net_device *dev = phonet_route_get_rcu(net, addr << 2);
302
303		if (!dev)
304			continue;
305
306		err = fill_route(skb, READ_ONCE(dev->ifindex), addr << 2,
307				 NETLINK_CB(cb->skb).portid,
308				 cb->nlh->nlmsg_seq, RTM_NEWROUTE);
309		if (err < 0)
310			break;
311	}
312	rcu_read_unlock();
313	cb->args[0] = addr;
314
315	return err;
316}
317
318static const struct rtnl_msg_handler phonet_rtnl_msg_handlers[] __initdata_or_module = {
319	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWADDR,
320	 .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
321	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELADDR,
322	 .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
323	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETADDR,
324	 .dumpit = getaddr_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},
325	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWROUTE,
326	 .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
327	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELROUTE,
328	 .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
329	{.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETROUTE,
330	 .dumpit = route_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},
331};
332
333int __init phonet_netlink_register(void)
334{
335	return rtnl_register_many(phonet_rtnl_msg_handlers);
336}