561 lines
12 KiB
C
561 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Management Component Transport Protocol (MCTP) - device implementation.
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*
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* Copyright (c) 2021 Code Construct
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* Copyright (c) 2021 Google
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*/
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#include <linux/if_arp.h>
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#include <linux/if_link.h>
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#include <linux/mctp.h>
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#include <linux/netdevice.h>
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#include <linux/rcupdate.h>
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#include <linux/rtnetlink.h>
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#include <net/addrconf.h>
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#include <net/netlink.h>
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#include <net/mctp.h>
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#include <net/mctpdevice.h>
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#include <net/sock.h>
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struct mctp_dump_cb {
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int h;
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int idx;
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size_t a_idx;
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};
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/* unlocked: caller must hold rcu_read_lock.
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* Returned mctp_dev has its refcount incremented, or NULL if unset.
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*/
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struct mctp_dev *__mctp_dev_get(const struct net_device *dev)
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{
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struct mctp_dev *mdev = rcu_dereference(dev->mctp_ptr);
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/* RCU guarantees that any mdev is still live.
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* Zero refcount implies a pending free, return NULL.
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*/
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if (mdev)
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if (!refcount_inc_not_zero(&mdev->refs))
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return NULL;
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return mdev;
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}
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/* Returned mctp_dev does not have refcount incremented. The returned pointer
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* remains live while rtnl_lock is held, as that prevents mctp_unregister()
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*/
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struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev)
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{
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return rtnl_dereference(dev->mctp_ptr);
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}
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static int mctp_addrinfo_size(void)
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{
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return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
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+ nla_total_size(1) // IFA_LOCAL
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+ nla_total_size(1) // IFA_ADDRESS
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;
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}
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/* flag should be NLM_F_MULTI for dump calls */
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static int mctp_fill_addrinfo(struct sk_buff *skb,
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struct mctp_dev *mdev, mctp_eid_t eid,
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int msg_type, u32 portid, u32 seq, int flag)
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{
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struct ifaddrmsg *hdr;
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struct nlmsghdr *nlh;
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nlh = nlmsg_put(skb, portid, seq,
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msg_type, sizeof(*hdr), flag);
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if (!nlh)
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return -EMSGSIZE;
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hdr = nlmsg_data(nlh);
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hdr->ifa_family = AF_MCTP;
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hdr->ifa_prefixlen = 0;
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hdr->ifa_flags = 0;
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hdr->ifa_scope = 0;
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hdr->ifa_index = mdev->dev->ifindex;
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if (nla_put_u8(skb, IFA_LOCAL, eid))
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goto cancel;
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if (nla_put_u8(skb, IFA_ADDRESS, eid))
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goto cancel;
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nlmsg_end(skb, nlh);
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return 0;
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cancel:
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nlmsg_cancel(skb, nlh);
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return -EMSGSIZE;
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}
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static int mctp_dump_dev_addrinfo(struct mctp_dev *mdev, struct sk_buff *skb,
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struct netlink_callback *cb)
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{
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struct mctp_dump_cb *mcb = (void *)cb->ctx;
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u32 portid, seq;
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int rc = 0;
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portid = NETLINK_CB(cb->skb).portid;
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seq = cb->nlh->nlmsg_seq;
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for (; mcb->a_idx < mdev->num_addrs; mcb->a_idx++) {
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rc = mctp_fill_addrinfo(skb, mdev, mdev->addrs[mcb->a_idx],
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RTM_NEWADDR, portid, seq, NLM_F_MULTI);
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if (rc < 0)
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break;
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}
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return rc;
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}
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static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb)
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{
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struct mctp_dump_cb *mcb = (void *)cb->ctx;
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struct net *net = sock_net(skb->sk);
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struct hlist_head *head;
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struct net_device *dev;
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struct ifaddrmsg *hdr;
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struct mctp_dev *mdev;
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int ifindex;
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int idx = 0, rc;
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hdr = nlmsg_data(cb->nlh);
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// filter by ifindex if requested
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ifindex = hdr->ifa_index;
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rcu_read_lock();
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for (; mcb->h < NETDEV_HASHENTRIES; mcb->h++, mcb->idx = 0) {
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idx = 0;
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head = &net->dev_index_head[mcb->h];
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hlist_for_each_entry_rcu(dev, head, index_hlist) {
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if (idx >= mcb->idx &&
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(ifindex == 0 || ifindex == dev->ifindex)) {
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mdev = __mctp_dev_get(dev);
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if (mdev) {
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rc = mctp_dump_dev_addrinfo(mdev,
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skb, cb);
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mctp_dev_put(mdev);
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// Error indicates full buffer, this
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// callback will get retried.
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if (rc < 0)
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goto out;
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}
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}
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idx++;
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// reset for next iteration
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mcb->a_idx = 0;
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}
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}
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out:
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rcu_read_unlock();
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mcb->idx = idx;
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return skb->len;
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}
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static void mctp_addr_notify(struct mctp_dev *mdev, mctp_eid_t eid, int msg_type,
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struct sk_buff *req_skb, struct nlmsghdr *req_nlh)
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{
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u32 portid = NETLINK_CB(req_skb).portid;
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struct net *net = dev_net(mdev->dev);
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struct sk_buff *skb;
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int rc = -ENOBUFS;
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skb = nlmsg_new(mctp_addrinfo_size(), GFP_KERNEL);
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if (!skb)
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goto out;
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rc = mctp_fill_addrinfo(skb, mdev, eid, msg_type,
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portid, req_nlh->nlmsg_seq, 0);
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if (rc < 0) {
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WARN_ON_ONCE(rc == -EMSGSIZE);
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goto out;
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}
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rtnl_notify(skb, net, portid, RTNLGRP_MCTP_IFADDR, req_nlh, GFP_KERNEL);
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return;
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out:
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kfree_skb(skb);
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rtnl_set_sk_err(net, RTNLGRP_MCTP_IFADDR, rc);
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}
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static const struct nla_policy ifa_mctp_policy[IFA_MAX + 1] = {
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[IFA_ADDRESS] = { .type = NLA_U8 },
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[IFA_LOCAL] = { .type = NLA_U8 },
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};
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static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct netlink_ext_ack *extack)
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{
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struct net *net = sock_net(skb->sk);
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struct nlattr *tb[IFA_MAX + 1];
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struct net_device *dev;
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struct mctp_addr *addr;
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struct mctp_dev *mdev;
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struct ifaddrmsg *ifm;
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unsigned long flags;
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u8 *tmp_addrs;
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int rc;
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rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
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extack);
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if (rc < 0)
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return rc;
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ifm = nlmsg_data(nlh);
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if (tb[IFA_LOCAL])
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addr = nla_data(tb[IFA_LOCAL]);
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else if (tb[IFA_ADDRESS])
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addr = nla_data(tb[IFA_ADDRESS]);
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else
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return -EINVAL;
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/* find device */
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dev = __dev_get_by_index(net, ifm->ifa_index);
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if (!dev)
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return -ENODEV;
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mdev = mctp_dev_get_rtnl(dev);
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if (!mdev)
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return -ENODEV;
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if (!mctp_address_unicast(addr->s_addr))
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return -EINVAL;
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/* Prevent duplicates. Under RTNL so don't need to lock for reading */
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if (memchr(mdev->addrs, addr->s_addr, mdev->num_addrs))
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return -EEXIST;
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tmp_addrs = kmalloc(mdev->num_addrs + 1, GFP_KERNEL);
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if (!tmp_addrs)
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return -ENOMEM;
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memcpy(tmp_addrs, mdev->addrs, mdev->num_addrs);
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tmp_addrs[mdev->num_addrs] = addr->s_addr;
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/* Lock to write */
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spin_lock_irqsave(&mdev->addrs_lock, flags);
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mdev->num_addrs++;
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swap(mdev->addrs, tmp_addrs);
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spin_unlock_irqrestore(&mdev->addrs_lock, flags);
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kfree(tmp_addrs);
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mctp_addr_notify(mdev, addr->s_addr, RTM_NEWADDR, skb, nlh);
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mctp_route_add_local(mdev, addr->s_addr);
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return 0;
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}
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static int mctp_rtm_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh,
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struct netlink_ext_ack *extack)
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{
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struct net *net = sock_net(skb->sk);
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struct nlattr *tb[IFA_MAX + 1];
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struct net_device *dev;
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struct mctp_addr *addr;
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struct mctp_dev *mdev;
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struct ifaddrmsg *ifm;
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unsigned long flags;
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u8 *pos;
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int rc;
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rc = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_mctp_policy,
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extack);
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if (rc < 0)
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return rc;
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ifm = nlmsg_data(nlh);
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if (tb[IFA_LOCAL])
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addr = nla_data(tb[IFA_LOCAL]);
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else if (tb[IFA_ADDRESS])
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addr = nla_data(tb[IFA_ADDRESS]);
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else
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return -EINVAL;
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/* find device */
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dev = __dev_get_by_index(net, ifm->ifa_index);
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if (!dev)
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return -ENODEV;
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mdev = mctp_dev_get_rtnl(dev);
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if (!mdev)
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return -ENODEV;
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pos = memchr(mdev->addrs, addr->s_addr, mdev->num_addrs);
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if (!pos)
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return -ENOENT;
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rc = mctp_route_remove_local(mdev, addr->s_addr);
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// we can ignore -ENOENT in the case a route was already removed
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if (rc < 0 && rc != -ENOENT)
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return rc;
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spin_lock_irqsave(&mdev->addrs_lock, flags);
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memmove(pos, pos + 1, mdev->num_addrs - 1 - (pos - mdev->addrs));
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mdev->num_addrs--;
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spin_unlock_irqrestore(&mdev->addrs_lock, flags);
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mctp_addr_notify(mdev, addr->s_addr, RTM_DELADDR, skb, nlh);
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return 0;
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}
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void mctp_dev_hold(struct mctp_dev *mdev)
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{
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refcount_inc(&mdev->refs);
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}
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void mctp_dev_put(struct mctp_dev *mdev)
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{
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if (mdev && refcount_dec_and_test(&mdev->refs)) {
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kfree(mdev->addrs);
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dev_put(mdev->dev);
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kfree_rcu(mdev, rcu);
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}
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}
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void mctp_dev_release_key(struct mctp_dev *dev, struct mctp_sk_key *key)
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__must_hold(&key->lock)
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{
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if (!dev)
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return;
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if (dev->ops && dev->ops->release_flow)
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dev->ops->release_flow(dev, key);
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key->dev = NULL;
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mctp_dev_put(dev);
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}
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void mctp_dev_set_key(struct mctp_dev *dev, struct mctp_sk_key *key)
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__must_hold(&key->lock)
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{
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mctp_dev_hold(dev);
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key->dev = dev;
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}
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static struct mctp_dev *mctp_add_dev(struct net_device *dev)
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{
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struct mctp_dev *mdev;
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ASSERT_RTNL();
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mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
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if (!mdev)
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return ERR_PTR(-ENOMEM);
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spin_lock_init(&mdev->addrs_lock);
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mdev->net = mctp_default_net(dev_net(dev));
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/* associate to net_device */
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refcount_set(&mdev->refs, 1);
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rcu_assign_pointer(dev->mctp_ptr, mdev);
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dev_hold(dev);
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mdev->dev = dev;
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return mdev;
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}
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static int mctp_fill_link_af(struct sk_buff *skb,
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const struct net_device *dev, u32 ext_filter_mask)
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{
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struct mctp_dev *mdev;
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mdev = mctp_dev_get_rtnl(dev);
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if (!mdev)
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return -ENODATA;
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if (nla_put_u32(skb, IFLA_MCTP_NET, mdev->net))
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return -EMSGSIZE;
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return 0;
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}
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static size_t mctp_get_link_af_size(const struct net_device *dev,
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u32 ext_filter_mask)
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{
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struct mctp_dev *mdev;
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unsigned int ret;
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/* caller holds RCU */
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mdev = __mctp_dev_get(dev);
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if (!mdev)
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return 0;
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ret = nla_total_size(4); /* IFLA_MCTP_NET */
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mctp_dev_put(mdev);
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return ret;
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}
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static const struct nla_policy ifla_af_mctp_policy[IFLA_MCTP_MAX + 1] = {
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[IFLA_MCTP_NET] = { .type = NLA_U32 },
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};
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static int mctp_set_link_af(struct net_device *dev, const struct nlattr *attr,
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struct netlink_ext_ack *extack)
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{
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struct nlattr *tb[IFLA_MCTP_MAX + 1];
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struct mctp_dev *mdev;
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int rc;
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rc = nla_parse_nested(tb, IFLA_MCTP_MAX, attr, ifla_af_mctp_policy,
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NULL);
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if (rc)
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return rc;
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mdev = mctp_dev_get_rtnl(dev);
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if (!mdev)
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return 0;
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if (tb[IFLA_MCTP_NET])
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WRITE_ONCE(mdev->net, nla_get_u32(tb[IFLA_MCTP_NET]));
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return 0;
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}
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/* Matches netdev types that should have MCTP handling */
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static bool mctp_known(struct net_device *dev)
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{
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/* only register specific types (inc. NONE for TUN devices) */
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return dev->type == ARPHRD_MCTP ||
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dev->type == ARPHRD_LOOPBACK ||
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dev->type == ARPHRD_NONE;
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}
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static void mctp_unregister(struct net_device *dev)
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{
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struct mctp_dev *mdev;
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mdev = mctp_dev_get_rtnl(dev);
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if (mdev && !mctp_known(dev)) {
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// Sanity check, should match what was set in mctp_register
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netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d",
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__func__, dev->type);
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return;
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}
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if (!mdev)
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return;
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RCU_INIT_POINTER(mdev->dev->mctp_ptr, NULL);
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mctp_route_remove_dev(mdev);
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mctp_neigh_remove_dev(mdev);
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mctp_dev_put(mdev);
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}
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static int mctp_register(struct net_device *dev)
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{
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struct mctp_dev *mdev;
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/* Already registered? */
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mdev = rtnl_dereference(dev->mctp_ptr);
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if (mdev) {
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if (!mctp_known(dev))
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netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d",
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__func__, dev->type);
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return 0;
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}
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/* only register specific types */
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if (!mctp_known(dev))
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return 0;
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mdev = mctp_add_dev(dev);
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if (IS_ERR(mdev))
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return PTR_ERR(mdev);
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return 0;
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}
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static int mctp_dev_notify(struct notifier_block *this, unsigned long event,
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void *ptr)
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{
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struct net_device *dev = netdev_notifier_info_to_dev(ptr);
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int rc;
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switch (event) {
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case NETDEV_REGISTER:
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rc = mctp_register(dev);
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if (rc)
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return notifier_from_errno(rc);
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break;
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case NETDEV_UNREGISTER:
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mctp_unregister(dev);
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break;
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}
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return NOTIFY_OK;
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}
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static int mctp_register_netdevice(struct net_device *dev,
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const struct mctp_netdev_ops *ops)
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{
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struct mctp_dev *mdev;
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mdev = mctp_add_dev(dev);
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if (IS_ERR(mdev))
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return PTR_ERR(mdev);
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mdev->ops = ops;
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return register_netdevice(dev);
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}
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int mctp_register_netdev(struct net_device *dev,
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const struct mctp_netdev_ops *ops)
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{
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int rc;
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rtnl_lock();
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rc = mctp_register_netdevice(dev, ops);
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rtnl_unlock();
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return rc;
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}
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EXPORT_SYMBOL_GPL(mctp_register_netdev);
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void mctp_unregister_netdev(struct net_device *dev)
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{
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|
unregister_netdev(dev);
|
|
}
|
|
EXPORT_SYMBOL_GPL(mctp_unregister_netdev);
|
|
|
|
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);
|
|
}
|