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 24 static 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(mdev->dev); 29 struct mctp_neigh *neigh; 30 int rc; 31 32 mutex_lock(&net->mctp.neigh_lock); 33 if (mctp_neigh_lookup(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(&neigh->list); 49 neigh->dev = mdev; 50 mctp_dev_hold(neigh->dev); 51 neigh->eid = eid; 52 neigh->source = source; 53 memcpy(neigh->ha, lladdr, lladdr_len); 54 55 list_add_rcu(&neigh->list, &net->mctp.neighbours); 56 rc = 0; 57 out: 58 mutex_unlock(&net->mctp.neigh_lock); 59 return rc; 60 } 61 62 static 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(neigh->dev); 67 kfree(neigh); 68 } 69 70 /* Removes all neighbour entries referring to a device */ 71 void mctp_neigh_remove_dev(struct mctp_dev *mdev) 72 { 73 struct net *net = dev_net(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(&neigh->list); 80 /* TODO: immediate RTM_DELNEIGH */ 81 call_rcu(&neigh->rcu, __mctp_neigh_free); 82 } 83 } 84 85 mutex_unlock(&net->mctp.neigh_lock); 86 } 87 88 // TODO: add a "source" flag so netlink can only delete static neighbours? 89 static int mctp_neigh_remove(struct mctp_dev *mdev, mctp_eid_t eid) 90 { 91 struct net *net = dev_net(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 list_del_rcu(&neigh->list); 99 /* TODO: immediate RTM_DELNEIGH */ 100 call_rcu(&neigh->rcu, __mctp_neigh_free); 101 dropped = true; 102 } 103 } 104 105 mutex_unlock(&net->mctp.neigh_lock); 106 return dropped ? 0 : -ENOENT; 107 } 108 109 static const struct nla_policy nd_mctp_policy[NDA_MAX + 1] = { 110 [NDA_DST] = { .type = NLA_U8 }, 111 [NDA_LLADDR] = { .type = NLA_BINARY, .len = MAX_ADDR_LEN }, 112 }; 113 114 static int mctp_rtm_newneigh(struct sk_buff *skb, struct nlmsghdr *nlh, 115 struct netlink_ext_ack *extack) 116 { 117 struct net *net = sock_net(skb->sk); 118 struct net_device *dev; 119 struct mctp_dev *mdev; 120 struct ndmsg *ndm; 121 struct nlattr *tb[NDA_MAX + 1]; 122 int rc; 123 mctp_eid_t eid; 124 void *lladdr; 125 int lladdr_len; 126 127 rc = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, nd_mctp_policy, 128 extack); 129 if (rc < 0) { 130 NL_SET_ERR_MSG(extack, "lladdr too large?"); 131 return rc; 132 } 133 134 if (!tb[NDA_DST]) { 135 NL_SET_ERR_MSG(extack, "Neighbour EID must be specified"); 136 return -EINVAL; 137 } 138 139 if (!tb[NDA_LLADDR]) { 140 NL_SET_ERR_MSG(extack, "Neighbour lladdr must be specified"); 141 return -EINVAL; 142 } 143 144 eid = nla_get_u8(tb[NDA_DST]); 145 if (!mctp_address_ok(eid)) { 146 NL_SET_ERR_MSG(extack, "Invalid neighbour EID"); 147 return -EINVAL; 148 } 149 150 lladdr = nla_data(tb[NDA_LLADDR]); 151 lladdr_len = nla_len(tb[NDA_LLADDR]); 152 153 ndm = nlmsg_data(nlh); 154 155 dev = __dev_get_by_index(net, ndm->ndm_ifindex); 156 if (!dev) 157 return -ENODEV; 158 159 mdev = mctp_dev_get_rtnl(dev); 160 if (!mdev) 161 return -ENODEV; 162 163 if (lladdr_len != dev->addr_len) { 164 NL_SET_ERR_MSG(extack, "Wrong lladdr length"); 165 return -EINVAL; 166 } 167 168 return mctp_neigh_add(mdev, eid, MCTP_NEIGH_STATIC, 169 lladdr_len, lladdr); 170 } 171 172 static int mctp_rtm_delneigh(struct sk_buff *skb, struct nlmsghdr *nlh, 173 struct netlink_ext_ack *extack) 174 { 175 struct net *net = sock_net(skb->sk); 176 struct nlattr *tb[NDA_MAX + 1]; 177 struct net_device *dev; 178 struct mctp_dev *mdev; 179 struct ndmsg *ndm; 180 int rc; 181 mctp_eid_t eid; 182 183 rc = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, nd_mctp_policy, 184 extack); 185 if (rc < 0) { 186 NL_SET_ERR_MSG(extack, "incorrect format"); 187 return rc; 188 } 189 190 if (!tb[NDA_DST]) { 191 NL_SET_ERR_MSG(extack, "Neighbour EID must be specified"); 192 return -EINVAL; 193 } 194 eid = nla_get_u8(tb[NDA_DST]); 195 196 ndm = nlmsg_data(nlh); 197 dev = __dev_get_by_index(net, ndm->ndm_ifindex); 198 if (!dev) 199 return -ENODEV; 200 201 mdev = mctp_dev_get_rtnl(dev); 202 if (!mdev) 203 return -ENODEV; 204 205 return mctp_neigh_remove(mdev, eid); 206 } 207 208 static int mctp_fill_neigh(struct sk_buff *skb, u32 portid, u32 seq, int event, 209 unsigned int flags, struct mctp_neigh *neigh) 210 { 211 struct net_device *dev = neigh->dev->dev; 212 struct nlmsghdr *nlh; 213 struct ndmsg *hdr; 214 215 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags); 216 if (!nlh) 217 return -EMSGSIZE; 218 219 hdr = nlmsg_data(nlh); 220 hdr->ndm_family = AF_MCTP; 221 hdr->ndm_ifindex = dev->ifindex; 222 hdr->ndm_state = 0; // TODO other state bits? 223 if (neigh->source == MCTP_NEIGH_STATIC) 224 hdr->ndm_state |= NUD_PERMANENT; 225 hdr->ndm_flags = 0; 226 hdr->ndm_type = RTN_UNICAST; // TODO: is loopback RTN_LOCAL? 227 228 if (nla_put_u8(skb, NDA_DST, neigh->eid)) 229 goto cancel; 230 231 if (nla_put(skb, NDA_LLADDR, dev->addr_len, neigh->ha)) 232 goto cancel; 233 234 nlmsg_end(skb, nlh); 235 236 return 0; 237 cancel: 238 nlmsg_cancel(skb, nlh); 239 return -EMSGSIZE; 240 } 241 242 static int mctp_rtm_getneigh(struct sk_buff *skb, struct netlink_callback *cb) 243 { 244 struct net *net = sock_net(skb->sk); 245 int rc, idx, req_ifindex; 246 struct mctp_neigh *neigh; 247 struct ndmsg *ndmsg; 248 struct { 249 int idx; 250 } *cbctx = (void *)cb->ctx; 251 252 ndmsg = nlmsg_data(cb->nlh); 253 req_ifindex = ndmsg->ndm_ifindex; 254 255 idx = 0; 256 rcu_read_lock(); 257 list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) { 258 if (idx < cbctx->idx) 259 goto cont; 260 261 rc = 0; 262 if (req_ifindex == 0 || req_ifindex == neigh->dev->dev->ifindex) 263 rc = mctp_fill_neigh(skb, NETLINK_CB(cb->skb).portid, 264 cb->nlh->nlmsg_seq, 265 RTM_NEWNEIGH, NLM_F_MULTI, neigh); 266 267 if (rc) 268 break; 269 cont: 270 idx++; 271 } 272 rcu_read_unlock(); 273 274 cbctx->idx = idx; 275 return skb->len; 276 } 277 278 int mctp_neigh_lookup(struct mctp_dev *mdev, mctp_eid_t eid, void *ret_hwaddr) 279 { 280 struct net *net = dev_net(mdev->dev); 281 struct mctp_neigh *neigh; 282 int rc = -EHOSTUNREACH; // TODO: or ENOENT? 283 284 rcu_read_lock(); 285 list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) { 286 if (mdev == neigh->dev && eid == neigh->eid) { 287 if (ret_hwaddr) 288 memcpy(ret_hwaddr, neigh->ha, 289 sizeof(neigh->ha)); 290 rc = 0; 291 break; 292 } 293 } 294 rcu_read_unlock(); 295 return rc; 296 } 297 298 /* namespace registration */ 299 static int __net_init mctp_neigh_net_init(struct net *net) 300 { 301 struct netns_mctp *ns = &net->mctp; 302 303 INIT_LIST_HEAD(&ns->neighbours); 304 mutex_init(&ns->neigh_lock); 305 return 0; 306 } 307 308 static void __net_exit mctp_neigh_net_exit(struct net *net) 309 { 310 struct netns_mctp *ns = &net->mctp; 311 struct mctp_neigh *neigh; 312 313 list_for_each_entry(neigh, &ns->neighbours, list) 314 call_rcu(&neigh->rcu, __mctp_neigh_free); 315 } 316 317 /* net namespace implementation */ 318 319 static struct pernet_operations mctp_net_ops = { 320 .init = mctp_neigh_net_init, 321 .exit = mctp_neigh_net_exit, 322 }; 323 324 int __init mctp_neigh_init(void) 325 { 326 rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWNEIGH, 327 mctp_rtm_newneigh, NULL, 0); 328 rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELNEIGH, 329 mctp_rtm_delneigh, NULL, 0); 330 rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETNEIGH, 331 NULL, mctp_rtm_getneigh, 0); 332 333 return register_pernet_subsys(&mctp_net_ops); 334 } 335 336 void __exit mctp_neigh_exit(void) 337 { 338 unregister_pernet_subsys(&mctp_net_ops); 339 rtnl_unregister(PF_MCTP, RTM_GETNEIGH); 340 rtnl_unregister(PF_MCTP, RTM_DELNEIGH); 341 rtnl_unregister(PF_MCTP, RTM_NEWNEIGH); 342 } 343