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-rw-r--r--net/mctp/neigh.c343
1 files changed, 343 insertions, 0 deletions
diff --git a/net/mctp/neigh.c b/net/mctp/neigh.c
new file mode 100644
index 000000000..ffa0f9e09
--- /dev/null
+++ b/net/mctp/neigh.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Management Component Transport Protocol (MCTP) - routing
+ * implementation.
+ *
+ * This is currently based on a simple routing table, with no dst cache. The
+ * number of routes should stay fairly small, so the lookup cost is small.
+ *
+ * Copyright (c) 2021 Code Construct
+ * Copyright (c) 2021 Google
+ */
+
+#include <linux/idr.h>
+#include <linux/mctp.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <linux/skbuff.h>
+
+#include <net/mctp.h>
+#include <net/mctpdevice.h>
+#include <net/netlink.h>
+#include <net/sock.h>
+
+static int mctp_neigh_add(struct mctp_dev *mdev, mctp_eid_t eid,
+ enum mctp_neigh_source source,
+ size_t lladdr_len, const void *lladdr)
+{
+ struct net *net = dev_net(mdev->dev);
+ struct mctp_neigh *neigh;
+ int rc;
+
+ mutex_lock(&net->mctp.neigh_lock);
+ if (mctp_neigh_lookup(mdev, eid, NULL) == 0) {
+ rc = -EEXIST;
+ goto out;
+ }
+
+ if (lladdr_len > sizeof(neigh->ha)) {
+ rc = -EINVAL;
+ goto out;
+ }
+
+ neigh = kzalloc(sizeof(*neigh), GFP_KERNEL);
+ if (!neigh) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ INIT_LIST_HEAD(&neigh->list);
+ neigh->dev = mdev;
+ mctp_dev_hold(neigh->dev);
+ neigh->eid = eid;
+ neigh->source = source;
+ memcpy(neigh->ha, lladdr, lladdr_len);
+
+ list_add_rcu(&neigh->list, &net->mctp.neighbours);
+ rc = 0;
+out:
+ mutex_unlock(&net->mctp.neigh_lock);
+ return rc;
+}
+
+static void __mctp_neigh_free(struct rcu_head *rcu)
+{
+ struct mctp_neigh *neigh = container_of(rcu, struct mctp_neigh, rcu);
+
+ mctp_dev_put(neigh->dev);
+ kfree(neigh);
+}
+
+/* Removes all neighbour entries referring to a device */
+void mctp_neigh_remove_dev(struct mctp_dev *mdev)
+{
+ struct net *net = dev_net(mdev->dev);
+ struct mctp_neigh *neigh, *tmp;
+
+ mutex_lock(&net->mctp.neigh_lock);
+ list_for_each_entry_safe(neigh, tmp, &net->mctp.neighbours, list) {
+ if (neigh->dev == mdev) {
+ list_del_rcu(&neigh->list);
+ /* TODO: immediate RTM_DELNEIGH */
+ call_rcu(&neigh->rcu, __mctp_neigh_free);
+ }
+ }
+
+ mutex_unlock(&net->mctp.neigh_lock);
+}
+
+static int mctp_neigh_remove(struct mctp_dev *mdev, mctp_eid_t eid,
+ enum mctp_neigh_source source)
+{
+ struct net *net = dev_net(mdev->dev);
+ struct mctp_neigh *neigh, *tmp;
+ bool dropped = false;
+
+ mutex_lock(&net->mctp.neigh_lock);
+ list_for_each_entry_safe(neigh, tmp, &net->mctp.neighbours, list) {
+ if (neigh->dev == mdev && neigh->eid == eid &&
+ neigh->source == source) {
+ list_del_rcu(&neigh->list);
+ /* TODO: immediate RTM_DELNEIGH */
+ call_rcu(&neigh->rcu, __mctp_neigh_free);
+ dropped = true;
+ }
+ }
+
+ mutex_unlock(&net->mctp.neigh_lock);
+ return dropped ? 0 : -ENOENT;
+}
+
+static const struct nla_policy nd_mctp_policy[NDA_MAX + 1] = {
+ [NDA_DST] = { .type = NLA_U8 },
+ [NDA_LLADDR] = { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
+};
+
+static int mctp_rtm_newneigh(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ struct net *net = sock_net(skb->sk);
+ struct net_device *dev;
+ struct mctp_dev *mdev;
+ struct ndmsg *ndm;
+ struct nlattr *tb[NDA_MAX + 1];
+ int rc;
+ mctp_eid_t eid;
+ void *lladdr;
+ int lladdr_len;
+
+ rc = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, nd_mctp_policy,
+ extack);
+ if (rc < 0) {
+ NL_SET_ERR_MSG(extack, "lladdr too large?");
+ return rc;
+ }
+
+ if (!tb[NDA_DST]) {
+ NL_SET_ERR_MSG(extack, "Neighbour EID must be specified");
+ return -EINVAL;
+ }
+
+ if (!tb[NDA_LLADDR]) {
+ NL_SET_ERR_MSG(extack, "Neighbour lladdr must be specified");
+ return -EINVAL;
+ }
+
+ eid = nla_get_u8(tb[NDA_DST]);
+ if (!mctp_address_unicast(eid)) {
+ NL_SET_ERR_MSG(extack, "Invalid neighbour EID");
+ return -EINVAL;
+ }
+
+ lladdr = nla_data(tb[NDA_LLADDR]);
+ lladdr_len = nla_len(tb[NDA_LLADDR]);
+
+ ndm = nlmsg_data(nlh);
+
+ dev = __dev_get_by_index(net, ndm->ndm_ifindex);
+ if (!dev)
+ return -ENODEV;
+
+ mdev = mctp_dev_get_rtnl(dev);
+ if (!mdev)
+ return -ENODEV;
+
+ if (lladdr_len != dev->addr_len) {
+ NL_SET_ERR_MSG(extack, "Wrong lladdr length");
+ return -EINVAL;
+ }
+
+ return mctp_neigh_add(mdev, eid, MCTP_NEIGH_STATIC,
+ lladdr_len, lladdr);
+}
+
+static int mctp_rtm_delneigh(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ struct net *net = sock_net(skb->sk);
+ struct nlattr *tb[NDA_MAX + 1];
+ struct net_device *dev;
+ struct mctp_dev *mdev;
+ struct ndmsg *ndm;
+ int rc;
+ mctp_eid_t eid;
+
+ rc = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, nd_mctp_policy,
+ extack);
+ if (rc < 0) {
+ NL_SET_ERR_MSG(extack, "incorrect format");
+ return rc;
+ }
+
+ if (!tb[NDA_DST]) {
+ NL_SET_ERR_MSG(extack, "Neighbour EID must be specified");
+ return -EINVAL;
+ }
+ eid = nla_get_u8(tb[NDA_DST]);
+
+ ndm = nlmsg_data(nlh);
+ dev = __dev_get_by_index(net, ndm->ndm_ifindex);
+ if (!dev)
+ return -ENODEV;
+
+ mdev = mctp_dev_get_rtnl(dev);
+ if (!mdev)
+ return -ENODEV;
+
+ return mctp_neigh_remove(mdev, eid, MCTP_NEIGH_STATIC);
+}
+
+static int mctp_fill_neigh(struct sk_buff *skb, u32 portid, u32 seq, int event,
+ unsigned int flags, struct mctp_neigh *neigh)
+{
+ struct net_device *dev = neigh->dev->dev;
+ struct nlmsghdr *nlh;
+ struct ndmsg *hdr;
+
+ nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags);
+ if (!nlh)
+ return -EMSGSIZE;
+
+ hdr = nlmsg_data(nlh);
+ hdr->ndm_family = AF_MCTP;
+ hdr->ndm_ifindex = dev->ifindex;
+ hdr->ndm_state = 0; // TODO other state bits?
+ if (neigh->source == MCTP_NEIGH_STATIC)
+ hdr->ndm_state |= NUD_PERMANENT;
+ hdr->ndm_flags = 0;
+ hdr->ndm_type = RTN_UNICAST; // TODO: is loopback RTN_LOCAL?
+
+ if (nla_put_u8(skb, NDA_DST, neigh->eid))
+ goto cancel;
+
+ if (nla_put(skb, NDA_LLADDR, dev->addr_len, neigh->ha))
+ goto cancel;
+
+ nlmsg_end(skb, nlh);
+
+ return 0;
+cancel:
+ nlmsg_cancel(skb, nlh);
+ return -EMSGSIZE;
+}
+
+static int mctp_rtm_getneigh(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct net *net = sock_net(skb->sk);
+ int rc, idx, req_ifindex;
+ struct mctp_neigh *neigh;
+ struct ndmsg *ndmsg;
+ struct {
+ int idx;
+ } *cbctx = (void *)cb->ctx;
+
+ ndmsg = nlmsg_data(cb->nlh);
+ req_ifindex = ndmsg->ndm_ifindex;
+
+ idx = 0;
+ rcu_read_lock();
+ list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) {
+ if (idx < cbctx->idx)
+ goto cont;
+
+ rc = 0;
+ if (req_ifindex == 0 || req_ifindex == neigh->dev->dev->ifindex)
+ rc = mctp_fill_neigh(skb, NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq,
+ RTM_NEWNEIGH, NLM_F_MULTI, neigh);
+
+ if (rc)
+ break;
+cont:
+ idx++;
+ }
+ rcu_read_unlock();
+
+ cbctx->idx = idx;
+ return skb->len;
+}
+
+int mctp_neigh_lookup(struct mctp_dev *mdev, mctp_eid_t eid, void *ret_hwaddr)
+{
+ struct net *net = dev_net(mdev->dev);
+ struct mctp_neigh *neigh;
+ int rc = -EHOSTUNREACH; // TODO: or ENOENT?
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) {
+ if (mdev == neigh->dev && eid == neigh->eid) {
+ if (ret_hwaddr)
+ memcpy(ret_hwaddr, neigh->ha,
+ sizeof(neigh->ha));
+ rc = 0;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ return rc;
+}
+
+/* namespace registration */
+static int __net_init mctp_neigh_net_init(struct net *net)
+{
+ struct netns_mctp *ns = &net->mctp;
+
+ INIT_LIST_HEAD(&ns->neighbours);
+ mutex_init(&ns->neigh_lock);
+ return 0;
+}
+
+static void __net_exit mctp_neigh_net_exit(struct net *net)
+{
+ struct netns_mctp *ns = &net->mctp;
+ struct mctp_neigh *neigh;
+
+ list_for_each_entry(neigh, &ns->neighbours, list)
+ call_rcu(&neigh->rcu, __mctp_neigh_free);
+}
+
+/* net namespace implementation */
+
+static struct pernet_operations mctp_net_ops = {
+ .init = mctp_neigh_net_init,
+ .exit = mctp_neigh_net_exit,
+};
+
+int __init mctp_neigh_init(void)
+{
+ rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWNEIGH,
+ mctp_rtm_newneigh, NULL, 0);
+ rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELNEIGH,
+ mctp_rtm_delneigh, NULL, 0);
+ rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETNEIGH,
+ NULL, mctp_rtm_getneigh, 0);
+
+ return register_pernet_subsys(&mctp_net_ops);
+}
+
+void __exit mctp_neigh_exit(void)
+{
+ unregister_pernet_subsys(&mctp_net_ops);
+ rtnl_unregister(PF_MCTP, RTM_GETNEIGH);
+ rtnl_unregister(PF_MCTP, RTM_DELNEIGH);
+ rtnl_unregister(PF_MCTP, RTM_NEWNEIGH);
+}