1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Management Component Transport Protocol (MCTP) - routing
4 * implementation.
5 *
6 * This is currently based on a simple routing table, with no dst cache. The
7 * number of routes should stay fairly small, so the lookup cost is small.
8 *
9 * Copyright (c) 2021 Code Construct
10 * Copyright (c) 2021 Google
11 */
12
13#include <linux/idr.h>
14#include <linux/mctp.h>
15#include <linux/netdevice.h>
16#include <linux/rtnetlink.h>
17#include <linux/skbuff.h>
18
19#include <net/mctp.h>
20#include <net/mctpdevice.h>
21#include <net/netlink.h>
22#include <net/sock.h>
23
24static int mctp_neigh_add(struct mctp_dev *mdev, mctp_eid_t eid,
25 enum mctp_neigh_source source,
26 size_t lladdr_len, const void *lladdr)
27{
28 struct net *net = dev_net(dev: mdev->dev);
29 struct mctp_neigh *neigh;
30 int rc;
31
32 mutex_lock(&net->mctp.neigh_lock);
33 if (mctp_neigh_lookup(dev: mdev, eid, NULL) == 0) {
34 rc = -EEXIST;
35 goto out;
36 }
37
38 if (lladdr_len > sizeof(neigh->ha)) {
39 rc = -EINVAL;
40 goto out;
41 }
42
43 neigh = kzalloc(sizeof(*neigh), GFP_KERNEL);
44 if (!neigh) {
45 rc = -ENOMEM;
46 goto out;
47 }
48 INIT_LIST_HEAD(list: &neigh->list);
49 neigh->dev = mdev;
50 mctp_dev_hold(mdev: neigh->dev);
51 neigh->eid = eid;
52 neigh->source = source;
53 memcpy(neigh->ha, lladdr, lladdr_len);
54
55 list_add_rcu(new: &neigh->list, head: &net->mctp.neighbours);
56 rc = 0;
57out:
58 mutex_unlock(lock: &net->mctp.neigh_lock);
59 return rc;
60}
61
62static void __mctp_neigh_free(struct rcu_head *rcu)
63{
64 struct mctp_neigh *neigh = container_of(rcu, struct mctp_neigh, rcu);
65
66 mctp_dev_put(mdev: neigh->dev);
67 kfree(objp: neigh);
68}
69
70/* Removes all neighbour entries referring to a device */
71void mctp_neigh_remove_dev(struct mctp_dev *mdev)
72{
73 struct net *net = dev_net(dev: mdev->dev);
74 struct mctp_neigh *neigh, *tmp;
75
76 mutex_lock(&net->mctp.neigh_lock);
77 list_for_each_entry_safe(neigh, tmp, &net->mctp.neighbours, list) {
78 if (neigh->dev == mdev) {
79 list_del_rcu(entry: &neigh->list);
80 /* TODO: immediate RTM_DELNEIGH */
81 call_rcu(head: &neigh->rcu, func: __mctp_neigh_free);
82 }
83 }
84
85 mutex_unlock(lock: &net->mctp.neigh_lock);
86}
87
88static int mctp_neigh_remove(struct mctp_dev *mdev, mctp_eid_t eid,
89 enum mctp_neigh_source source)
90{
91 struct net *net = dev_net(dev: mdev->dev);
92 struct mctp_neigh *neigh, *tmp;
93 bool dropped = false;
94
95 mutex_lock(&net->mctp.neigh_lock);
96 list_for_each_entry_safe(neigh, tmp, &net->mctp.neighbours, list) {
97 if (neigh->dev == mdev && neigh->eid == eid &&
98 neigh->source == source) {
99 list_del_rcu(entry: &neigh->list);
100 /* TODO: immediate RTM_DELNEIGH */
101 call_rcu(head: &neigh->rcu, func: __mctp_neigh_free);
102 dropped = true;
103 }
104 }
105
106 mutex_unlock(lock: &net->mctp.neigh_lock);
107 return dropped ? 0 : -ENOENT;
108}
109
110static const struct nla_policy nd_mctp_policy[NDA_MAX + 1] = {
111 [NDA_DST] = { .type = NLA_U8 },
112 [NDA_LLADDR] = { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
113};
114
115static int mctp_rtm_newneigh(struct sk_buff *skb, struct nlmsghdr *nlh,
116 struct netlink_ext_ack *extack)
117{
118 struct net *net = sock_net(sk: skb->sk);
119 struct net_device *dev;
120 struct mctp_dev *mdev;
121 struct ndmsg *ndm;
122 struct nlattr *tb[NDA_MAX + 1];
123 int rc;
124 mctp_eid_t eid;
125 void *lladdr;
126 int lladdr_len;
127
128 rc = nlmsg_parse(nlh, hdrlen: sizeof(*ndm), tb, NDA_MAX, policy: nd_mctp_policy,
129 extack);
130 if (rc < 0) {
131 NL_SET_ERR_MSG(extack, "lladdr too large?");
132 return rc;
133 }
134
135 if (!tb[NDA_DST]) {
136 NL_SET_ERR_MSG(extack, "Neighbour EID must be specified");
137 return -EINVAL;
138 }
139
140 if (!tb[NDA_LLADDR]) {
141 NL_SET_ERR_MSG(extack, "Neighbour lladdr must be specified");
142 return -EINVAL;
143 }
144
145 eid = nla_get_u8(nla: tb[NDA_DST]);
146 if (!mctp_address_unicast(eid)) {
147 NL_SET_ERR_MSG(extack, "Invalid neighbour EID");
148 return -EINVAL;
149 }
150
151 lladdr = nla_data(nla: tb[NDA_LLADDR]);
152 lladdr_len = nla_len(nla: tb[NDA_LLADDR]);
153
154 ndm = nlmsg_data(nlh);
155
156 dev = __dev_get_by_index(net, ifindex: ndm->ndm_ifindex);
157 if (!dev)
158 return -ENODEV;
159
160 mdev = mctp_dev_get_rtnl(dev);
161 if (!mdev)
162 return -ENODEV;
163
164 if (lladdr_len != dev->addr_len) {
165 NL_SET_ERR_MSG(extack, "Wrong lladdr length");
166 return -EINVAL;
167 }
168
169 return mctp_neigh_add(mdev, eid, source: MCTP_NEIGH_STATIC,
170 lladdr_len, lladdr);
171}
172
173static int mctp_rtm_delneigh(struct sk_buff *skb, struct nlmsghdr *nlh,
174 struct netlink_ext_ack *extack)
175{
176 struct net *net = sock_net(sk: skb->sk);
177 struct nlattr *tb[NDA_MAX + 1];
178 struct net_device *dev;
179 struct mctp_dev *mdev;
180 struct ndmsg *ndm;
181 int rc;
182 mctp_eid_t eid;
183
184 rc = nlmsg_parse(nlh, hdrlen: sizeof(*ndm), tb, NDA_MAX, policy: nd_mctp_policy,
185 extack);
186 if (rc < 0) {
187 NL_SET_ERR_MSG(extack, "incorrect format");
188 return rc;
189 }
190
191 if (!tb[NDA_DST]) {
192 NL_SET_ERR_MSG(extack, "Neighbour EID must be specified");
193 return -EINVAL;
194 }
195 eid = nla_get_u8(nla: tb[NDA_DST]);
196
197 ndm = nlmsg_data(nlh);
198 dev = __dev_get_by_index(net, ifindex: ndm->ndm_ifindex);
199 if (!dev)
200 return -ENODEV;
201
202 mdev = mctp_dev_get_rtnl(dev);
203 if (!mdev)
204 return -ENODEV;
205
206 return mctp_neigh_remove(mdev, eid, source: MCTP_NEIGH_STATIC);
207}
208
209static int mctp_fill_neigh(struct sk_buff *skb, u32 portid, u32 seq, int event,
210 unsigned int flags, struct mctp_neigh *neigh)
211{
212 struct net_device *dev = neigh->dev->dev;
213 struct nlmsghdr *nlh;
214 struct ndmsg *hdr;
215
216 nlh = nlmsg_put(skb, portid, seq, type: event, payload: sizeof(*hdr), flags);
217 if (!nlh)
218 return -EMSGSIZE;
219
220 hdr = nlmsg_data(nlh);
221 hdr->ndm_family = AF_MCTP;
222 hdr->ndm_ifindex = dev->ifindex;
223 hdr->ndm_state = 0; // TODO other state bits?
224 if (neigh->source == MCTP_NEIGH_STATIC)
225 hdr->ndm_state |= NUD_PERMANENT;
226 hdr->ndm_flags = 0;
227 hdr->ndm_type = RTN_UNICAST; // TODO: is loopback RTN_LOCAL?
228
229 if (nla_put_u8(skb, attrtype: NDA_DST, value: neigh->eid))
230 goto cancel;
231
232 if (nla_put(skb, attrtype: NDA_LLADDR, attrlen: dev->addr_len, data: neigh->ha))
233 goto cancel;
234
235 nlmsg_end(skb, nlh);
236
237 return 0;
238cancel:
239 nlmsg_cancel(skb, nlh);
240 return -EMSGSIZE;
241}
242
243static int mctp_rtm_getneigh(struct sk_buff *skb, struct netlink_callback *cb)
244{
245 struct net *net = sock_net(sk: skb->sk);
246 int rc, idx, req_ifindex;
247 struct mctp_neigh *neigh;
248 struct ndmsg *ndmsg;
249 struct {
250 int idx;
251 } *cbctx = (void *)cb->ctx;
252
253 ndmsg = nlmsg_payload(nlh: cb->nlh, len: sizeof(*ndmsg));
254 if (!ndmsg)
255 return -EINVAL;
256
257 req_ifindex = ndmsg->ndm_ifindex;
258
259 idx = 0;
260 rcu_read_lock();
261 list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) {
262 if (idx < cbctx->idx)
263 goto cont;
264
265 rc = 0;
266 if (req_ifindex == 0 || req_ifindex == neigh->dev->dev->ifindex)
267 rc = mctp_fill_neigh(skb, NETLINK_CB(cb->skb).portid,
268 seq: cb->nlh->nlmsg_seq,
269 RTM_NEWNEIGH, NLM_F_MULTI, neigh);
270
271 if (rc)
272 break;
273cont:
274 idx++;
275 }
276 rcu_read_unlock();
277
278 cbctx->idx = idx;
279 return skb->len;
280}
281
282int mctp_neigh_lookup(struct mctp_dev *mdev, mctp_eid_t eid, void *ret_hwaddr)
283{
284 struct net *net = dev_net(dev: mdev->dev);
285 struct mctp_neigh *neigh;
286 int rc = -EHOSTUNREACH; // TODO: or ENOENT?
287
288 rcu_read_lock();
289 list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) {
290 if (mdev == neigh->dev && eid == neigh->eid) {
291 if (ret_hwaddr)
292 memcpy(ret_hwaddr, neigh->ha,
293 sizeof(neigh->ha));
294 rc = 0;
295 break;
296 }
297 }
298 rcu_read_unlock();
299 return rc;
300}
301
302/* namespace registration */
303static int __net_init mctp_neigh_net_init(struct net *net)
304{
305 struct netns_mctp *ns = &net->mctp;
306
307 INIT_LIST_HEAD(list: &ns->neighbours);
308 mutex_init(&ns->neigh_lock);
309 return 0;
310}
311
312static void __net_exit mctp_neigh_net_exit(struct net *net)
313{
314 struct netns_mctp *ns = &net->mctp;
315 struct mctp_neigh *neigh;
316
317 list_for_each_entry(neigh, &ns->neighbours, list)
318 call_rcu(head: &neigh->rcu, func: __mctp_neigh_free);
319}
320
321/* net namespace implementation */
322
323static struct pernet_operations mctp_net_ops = {
324 .init = mctp_neigh_net_init,
325 .exit = mctp_neigh_net_exit,
326};
327
328static const struct rtnl_msg_handler mctp_neigh_rtnl_msg_handlers[] = {
329 {THIS_MODULE, PF_MCTP, RTM_NEWNEIGH, mctp_rtm_newneigh, NULL, 0},
330 {THIS_MODULE, PF_MCTP, RTM_DELNEIGH, mctp_rtm_delneigh, NULL, 0},
331 {THIS_MODULE, PF_MCTP, RTM_GETNEIGH, NULL, mctp_rtm_getneigh, 0},
332};
333
334int __init mctp_neigh_init(void)
335{
336 int err;
337
338 err = register_pernet_subsys(&mctp_net_ops);
339 if (err)
340 return err;
341
342 err = rtnl_register_many(mctp_neigh_rtnl_msg_handlers);
343 if (err)
344 unregister_pernet_subsys(&mctp_net_ops);
345
346 return err;
347}
348
349void mctp_neigh_exit(void)
350{
351 rtnl_unregister_many(mctp_neigh_rtnl_msg_handlers);
352 unregister_pernet_subsys(&mctp_net_ops);
353}
354

source code of linux/net/mctp/neigh.c