--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Management Component Transport Protocol (MCTP) - device implementation.
+ *
+ * Copyright (c) 2021 Code Construct
+ * Copyright (c) 2021 Google
+ */
+
+#include <linux/if_link.h>
+#include <linux/mctp.h>
+#include <linux/netdevice.h>
+#include <linux/rcupdate.h>
+#include <linux/rtnetlink.h>
+
+#include <net/addrconf.h>
+#include <net/netlink.h>
+#include <net/mctp.h>
+#include <net/mctpdevice.h>
+#include <net/sock.h>
+
+struct mctp_dump_cb {
+ int h;
+ int idx;
+ size_t a_idx;
+};
+
+/* unlocked: caller must hold rcu_read_lock */
+struct mctp_dev *__mctp_dev_get(const struct net_device *dev)
+{
+ return rcu_dereference(dev->mctp_ptr);
+}
+
+struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev)
+{
+ return rtnl_dereference(dev->mctp_ptr);
+}
+
+static void mctp_dev_destroy(struct mctp_dev *mdev)
+{
+ struct net_device *dev = mdev->dev;
+
+ dev_put(dev);
+ kfree_rcu(mdev, rcu);
+}
+
+static int mctp_fill_addrinfo(struct sk_buff *skb, struct netlink_callback *cb,
+ struct mctp_dev *mdev, mctp_eid_t eid)
+{
+ struct ifaddrmsg *hdr;
+ struct nlmsghdr *nlh;
+
+ nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+ RTM_NEWADDR, sizeof(*hdr), NLM_F_MULTI);
+ if (!nlh)
+ return -EMSGSIZE;
+
+ hdr = nlmsg_data(nlh);
+ hdr->ifa_family = AF_MCTP;
+ hdr->ifa_prefixlen = 0;
+ hdr->ifa_flags = 0;
+ hdr->ifa_scope = 0;
+ hdr->ifa_index = mdev->dev->ifindex;
+
+ if (nla_put_u8(skb, IFA_LOCAL, eid))
+ goto cancel;
+
+ if (nla_put_u8(skb, IFA_ADDRESS, eid))
+ goto cancel;
+
+ nlmsg_end(skb, nlh);
+
+ return 0;
+
+cancel:
+ nlmsg_cancel(skb, nlh);
+ return -EMSGSIZE;
+}
+
+static int mctp_dump_dev_addrinfo(struct mctp_dev *mdev, struct sk_buff *skb,
+ struct netlink_callback *cb)
+{
+ struct mctp_dump_cb *mcb = (void *)cb->ctx;
+ int rc = 0;
+
+ for (; mcb->a_idx < mdev->num_addrs; mcb->a_idx++) {
+ rc = mctp_fill_addrinfo(skb, cb, mdev, mdev->addrs[mcb->a_idx]);
+ if (rc < 0)
+ break;
+ }
+
+ return rc;
+}
+
+static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct mctp_dump_cb *mcb = (void *)cb->ctx;
+ struct net *net = sock_net(skb->sk);
+ struct hlist_head *head;
+ struct net_device *dev;
+ struct ifaddrmsg *hdr;
+ struct mctp_dev *mdev;
+ int ifindex;
+ int idx, rc;
+
+ hdr = nlmsg_data(cb->nlh);
+ // filter by ifindex if requested
+ ifindex = hdr->ifa_index;
+
+ rcu_read_lock();
+ for (; mcb->h < NETDEV_HASHENTRIES; mcb->h++, mcb->idx = 0) {
+ idx = 0;
+ head = &net->dev_index_head[mcb->h];
+ hlist_for_each_entry_rcu(dev, head, index_hlist) {
+ if (idx >= mcb->idx &&
+ (ifindex == 0 || ifindex == dev->ifindex)) {
+ mdev = __mctp_dev_get(dev);
+ if (mdev) {
+ rc = mctp_dump_dev_addrinfo(mdev,
+ skb, cb);
+ // Error indicates full buffer, this
+ // callback will get retried.
+ if (rc < 0)
+ goto out;
+ }
+ }
+ idx++;
+ // reset for next iteration
+ mcb->a_idx = 0;
+ }
+ }
+out:
+ rcu_read_unlock();
+ mcb->idx = idx;
+
+ return skb->len;
+}
+
+static const struct nla_policy ifa_mctp_policy[IFA_MAX + 1] = {
+ [IFA_ADDRESS] = { .type = NLA_U8 },
+ [IFA_LOCAL] = { .type = NLA_U8 },
+};
+
+static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ struct net *net = sock_net(skb->sk);
+ struct nlattr *tb[IFA_MAX + 1];
+ struct net_device *dev;
+ struct mctp_addr *addr;
+ struct mctp_dev *mdev;
+ struct ifaddrmsg *ifm;
+ unsigned long flags;
+ u8 *tmp_addrs;
+ int rc;
+
+ rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
+ extack);
+ if (rc < 0)
+ return rc;
+
+ ifm = nlmsg_data(nlh);
+
+ if (tb[IFA_LOCAL])
+ addr = nla_data(tb[IFA_LOCAL]);
+ else if (tb[IFA_ADDRESS])
+ addr = nla_data(tb[IFA_ADDRESS]);
+ else
+ return -EINVAL;
+
+ /* find device */
+ dev = __dev_get_by_index(net, ifm->ifa_index);
+ if (!dev)
+ return -ENODEV;
+
+ mdev = mctp_dev_get_rtnl(dev);
+ if (!mdev)
+ return -ENODEV;
+
+ if (!mctp_address_ok(addr->s_addr))
+ return -EINVAL;
+
+ /* Prevent duplicates. Under RTNL so don't need to lock for reading */
+ if (memchr(mdev->addrs, addr->s_addr, mdev->num_addrs))
+ return -EEXIST;
+
+ tmp_addrs = kmalloc(mdev->num_addrs + 1, GFP_KERNEL);
+ if (!tmp_addrs)
+ return -ENOMEM;
+ memcpy(tmp_addrs, mdev->addrs, mdev->num_addrs);
+ tmp_addrs[mdev->num_addrs] = addr->s_addr;
+
+ /* Lock to write */
+ spin_lock_irqsave(&mdev->addrs_lock, flags);
+ mdev->num_addrs++;
+ swap(mdev->addrs, tmp_addrs);
+ spin_unlock_irqrestore(&mdev->addrs_lock, flags);
+
+ kfree(tmp_addrs);
+
+ return 0;
+}
+
+static int mctp_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
+ struct netlink_ext_ack *extack)
+{
+ struct net *net = sock_net(skb->sk);
+ struct nlattr *tb[IFA_MAX + 1];
+ struct net_device *dev;
+ struct mctp_addr *addr;
+ struct mctp_dev *mdev;
+ struct ifaddrmsg *ifm;
+ unsigned long flags;
+ u8 *pos;
+ int rc;
+
+ rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
+ extack);
+ if (rc < 0)
+ return rc;
+
+ ifm = nlmsg_data(nlh);
+
+ if (tb[IFA_LOCAL])
+ addr = nla_data(tb[IFA_LOCAL]);
+ else if (tb[IFA_ADDRESS])
+ addr = nla_data(tb[IFA_ADDRESS]);
+ else
+ return -EINVAL;
+
+ /* find device */
+ dev = __dev_get_by_index(net, ifm->ifa_index);
+ if (!dev)
+ return -ENODEV;
+
+ mdev = mctp_dev_get_rtnl(dev);
+ if (!mdev)
+ return -ENODEV;
+
+ pos = memchr(mdev->addrs, addr->s_addr, mdev->num_addrs);
+ if (!pos)
+ return -ENOENT;
+
+ spin_lock_irqsave(&mdev->addrs_lock, flags);
+ memmove(pos, pos + 1, mdev->num_addrs - 1 - (pos - mdev->addrs));
+ mdev->num_addrs--;
+ spin_unlock_irqrestore(&mdev->addrs_lock, flags);
+
+ return 0;
+}
+
+static struct mctp_dev *mctp_add_dev(struct net_device *dev)
+{
+ struct mctp_dev *mdev;
+
+ ASSERT_RTNL();
+
+ mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+ if (!mdev)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock_init(&mdev->addrs_lock);
+
+ mdev->net = MCTP_INITIAL_DEFAULT_NET;
+
+ /* associate to net_device */
+ rcu_assign_pointer(dev->mctp_ptr, mdev);
+ dev_hold(dev);
+ mdev->dev = dev;
+
+ return mdev;
+}
+
+static int mctp_fill_link_af(struct sk_buff *skb,
+ const struct net_device *dev, u32 ext_filter_mask)
+{
+ struct mctp_dev *mdev;
+
+ mdev = mctp_dev_get_rtnl(dev);
+ if (!mdev)
+ return -ENODATA;
+ if (nla_put_u32(skb, IFLA_MCTP_NET, mdev->net))
+ return -EMSGSIZE;
+ return 0;
+}
+
+static size_t mctp_get_link_af_size(const struct net_device *dev,
+ u32 ext_filter_mask)
+{
+ struct mctp_dev *mdev;
+ unsigned int ret;
+
+ /* caller holds RCU */
+ mdev = __mctp_dev_get(dev);
+ if (!mdev)
+ return 0;
+ ret = nla_total_size(4); /* IFLA_MCTP_NET */
+ return ret;
+}
+
+static const struct nla_policy ifla_af_mctp_policy[IFLA_MCTP_MAX + 1] = {
+ [IFLA_MCTP_NET] = { .type = NLA_U32 },
+};
+
+static int mctp_set_link_af(struct net_device *dev, const struct nlattr *attr,
+ struct netlink_ext_ack *extack)
+{
+ struct nlattr *tb[IFLA_MCTP_MAX + 1];
+ struct mctp_dev *mdev;
+ int rc;
+
+ rc = nla_parse_nested(tb, IFLA_MCTP_MAX, attr, ifla_af_mctp_policy,
+ NULL);
+ if (rc)
+ return rc;
+
+ mdev = mctp_dev_get_rtnl(dev);
+ if (!mdev)
+ return 0;
+
+ if (tb[IFLA_MCTP_NET])
+ WRITE_ONCE(mdev->net, nla_get_u32(tb[IFLA_MCTP_NET]));
+
+ return 0;
+}
+
+static void mctp_unregister(struct net_device *dev)
+{
+ struct mctp_dev *mdev;
+
+ mdev = mctp_dev_get_rtnl(dev);
+
+ if (!mdev)
+ return;
+
+ RCU_INIT_POINTER(mdev->dev->mctp_ptr, NULL);
+
+ kfree(mdev->addrs);
+
+ mctp_dev_destroy(mdev);
+}
+
+static int mctp_register(struct net_device *dev)
+{
+ struct mctp_dev *mdev;
+
+ /* Already registered? */
+ if (rtnl_dereference(dev->mctp_ptr))
+ return 0;
+
+ /* only register specific types; MCTP-specific and loopback for now */
+ if (dev->type != ARPHRD_MCTP && dev->type != ARPHRD_LOOPBACK)
+ return 0;
+
+ mdev = mctp_add_dev(dev);
+ if (IS_ERR(mdev))
+ return PTR_ERR(mdev);
+
+ return 0;
+}
+
+static int mctp_dev_notify(struct notifier_block *this, unsigned long event,
+ void *ptr)
+{
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ int rc;
+
+ switch (event) {
+ case NETDEV_REGISTER:
+ rc = mctp_register(dev);
+ if (rc)
+ return notifier_from_errno(rc);
+ break;
+ case NETDEV_UNREGISTER:
+ mctp_unregister(dev);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct rtnl_af_ops mctp_af_ops = {
+ .family = AF_MCTP,
+ .fill_link_af = mctp_fill_link_af,
+ .get_link_af_size = mctp_get_link_af_size,
+ .set_link_af = mctp_set_link_af,
+};
+
+static struct notifier_block mctp_dev_nb = {
+ .notifier_call = mctp_dev_notify,
+ .priority = ADDRCONF_NOTIFY_PRIORITY,
+};
+
+void __init mctp_device_init(void)
+{
+ register_netdevice_notifier(&mctp_dev_nb);
+
+ rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETADDR,
+ NULL, mctp_dump_addrinfo, 0);
+ rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWADDR,
+ mctp_rtm_newaddr, NULL, 0);
+ rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELADDR,
+ mctp_rtm_deladdr, NULL, 0);
+ rtnl_af_register(&mctp_af_ops);
+}
+
+void __exit mctp_device_exit(void)
+{
+ rtnl_af_unregister(&mctp_af_ops);
+ rtnl_unregister(PF_MCTP, RTM_DELADDR);
+ rtnl_unregister(PF_MCTP, RTM_NEWADDR);
+ rtnl_unregister(PF_MCTP, RTM_GETADDR);
+
+ unregister_netdevice_notifier(&mctp_dev_nb);
+}
projects / platform / kernel / linux-rpi.git / commitdiff