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![Jeremy Kerr](/assets/img/avatar_default.png)
Currently, we have mctp_address_ok(), which checks if an EID is in the "valid" range of 8-254 inclusive. However, 0 and 255 may also be valid addresses, depending on context. 0 is the NULL EID, which may be set when physical addressing is used. 255 is valid as a destination address for broadcasts. This change renames mctp_address_ok to mctp_address_unicast, and adds similar helpers for broadcast and null EIDs, which will be used in an upcoming commit. Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
343 lines
7.9 KiB
C
343 lines
7.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Management Component Transport Protocol (MCTP) - routing
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* implementation.
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*
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* This is currently based on a simple routing table, with no dst cache. The
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* number of routes should stay fairly small, so the lookup cost is small.
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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/idr.h>
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#include <linux/mctp.h>
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#include <linux/netdevice.h>
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#include <linux/rtnetlink.h>
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#include <linux/skbuff.h>
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#include <net/mctp.h>
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#include <net/mctpdevice.h>
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#include <net/netlink.h>
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#include <net/sock.h>
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static int mctp_neigh_add(struct mctp_dev *mdev, mctp_eid_t eid,
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enum mctp_neigh_source source,
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size_t lladdr_len, const void *lladdr)
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{
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struct net *net = dev_net(mdev->dev);
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struct mctp_neigh *neigh;
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int rc;
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mutex_lock(&net->mctp.neigh_lock);
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if (mctp_neigh_lookup(mdev, eid, NULL) == 0) {
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rc = -EEXIST;
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goto out;
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}
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if (lladdr_len > sizeof(neigh->ha)) {
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rc = -EINVAL;
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goto out;
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}
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neigh = kzalloc(sizeof(*neigh), GFP_KERNEL);
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if (!neigh) {
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rc = -ENOMEM;
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goto out;
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}
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INIT_LIST_HEAD(&neigh->list);
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neigh->dev = mdev;
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mctp_dev_hold(neigh->dev);
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neigh->eid = eid;
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neigh->source = source;
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memcpy(neigh->ha, lladdr, lladdr_len);
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list_add_rcu(&neigh->list, &net->mctp.neighbours);
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rc = 0;
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out:
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mutex_unlock(&net->mctp.neigh_lock);
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return rc;
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}
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static void __mctp_neigh_free(struct rcu_head *rcu)
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{
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struct mctp_neigh *neigh = container_of(rcu, struct mctp_neigh, rcu);
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mctp_dev_put(neigh->dev);
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kfree(neigh);
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}
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/* Removes all neighbour entries referring to a device */
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void mctp_neigh_remove_dev(struct mctp_dev *mdev)
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{
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struct net *net = dev_net(mdev->dev);
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struct mctp_neigh *neigh, *tmp;
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mutex_lock(&net->mctp.neigh_lock);
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list_for_each_entry_safe(neigh, tmp, &net->mctp.neighbours, list) {
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if (neigh->dev == mdev) {
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list_del_rcu(&neigh->list);
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/* TODO: immediate RTM_DELNEIGH */
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call_rcu(&neigh->rcu, __mctp_neigh_free);
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}
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}
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mutex_unlock(&net->mctp.neigh_lock);
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}
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static int mctp_neigh_remove(struct mctp_dev *mdev, mctp_eid_t eid,
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enum mctp_neigh_source source)
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{
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struct net *net = dev_net(mdev->dev);
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struct mctp_neigh *neigh, *tmp;
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bool dropped = false;
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mutex_lock(&net->mctp.neigh_lock);
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list_for_each_entry_safe(neigh, tmp, &net->mctp.neighbours, list) {
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if (neigh->dev == mdev && neigh->eid == eid &&
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neigh->source == source) {
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list_del_rcu(&neigh->list);
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/* TODO: immediate RTM_DELNEIGH */
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call_rcu(&neigh->rcu, __mctp_neigh_free);
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dropped = true;
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}
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}
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mutex_unlock(&net->mctp.neigh_lock);
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return dropped ? 0 : -ENOENT;
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}
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static const struct nla_policy nd_mctp_policy[NDA_MAX + 1] = {
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[NDA_DST] = { .type = NLA_U8 },
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[NDA_LLADDR] = { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
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};
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static int mctp_rtm_newneigh(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 net_device *dev;
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struct mctp_dev *mdev;
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struct ndmsg *ndm;
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struct nlattr *tb[NDA_MAX + 1];
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int rc;
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mctp_eid_t eid;
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void *lladdr;
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int lladdr_len;
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rc = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, nd_mctp_policy,
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extack);
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if (rc < 0) {
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NL_SET_ERR_MSG(extack, "lladdr too large?");
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return rc;
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}
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if (!tb[NDA_DST]) {
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NL_SET_ERR_MSG(extack, "Neighbour EID must be specified");
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return -EINVAL;
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}
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if (!tb[NDA_LLADDR]) {
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NL_SET_ERR_MSG(extack, "Neighbour lladdr must be specified");
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return -EINVAL;
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}
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eid = nla_get_u8(tb[NDA_DST]);
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if (!mctp_address_unicast(eid)) {
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NL_SET_ERR_MSG(extack, "Invalid neighbour EID");
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return -EINVAL;
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}
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lladdr = nla_data(tb[NDA_LLADDR]);
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lladdr_len = nla_len(tb[NDA_LLADDR]);
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ndm = nlmsg_data(nlh);
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dev = __dev_get_by_index(net, ndm->ndm_ifindex);
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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 (lladdr_len != dev->addr_len) {
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NL_SET_ERR_MSG(extack, "Wrong lladdr length");
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return -EINVAL;
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}
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return mctp_neigh_add(mdev, eid, MCTP_NEIGH_STATIC,
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lladdr_len, lladdr);
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}
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static int mctp_rtm_delneigh(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[NDA_MAX + 1];
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struct net_device *dev;
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struct mctp_dev *mdev;
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struct ndmsg *ndm;
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int rc;
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mctp_eid_t eid;
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rc = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, nd_mctp_policy,
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extack);
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if (rc < 0) {
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NL_SET_ERR_MSG(extack, "incorrect format");
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return rc;
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}
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if (!tb[NDA_DST]) {
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NL_SET_ERR_MSG(extack, "Neighbour EID must be specified");
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return -EINVAL;
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}
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eid = nla_get_u8(tb[NDA_DST]);
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ndm = nlmsg_data(nlh);
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dev = __dev_get_by_index(net, ndm->ndm_ifindex);
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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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return mctp_neigh_remove(mdev, eid, MCTP_NEIGH_STATIC);
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}
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static int mctp_fill_neigh(struct sk_buff *skb, u32 portid, u32 seq, int event,
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unsigned int flags, struct mctp_neigh *neigh)
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{
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struct net_device *dev = neigh->dev->dev;
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struct nlmsghdr *nlh;
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struct ndmsg *hdr;
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nlh = nlmsg_put(skb, portid, seq, event, sizeof(*hdr), flags);
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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->ndm_family = AF_MCTP;
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hdr->ndm_ifindex = dev->ifindex;
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hdr->ndm_state = 0; // TODO other state bits?
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if (neigh->source == MCTP_NEIGH_STATIC)
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hdr->ndm_state |= NUD_PERMANENT;
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hdr->ndm_flags = 0;
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hdr->ndm_type = RTN_UNICAST; // TODO: is loopback RTN_LOCAL?
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if (nla_put_u8(skb, NDA_DST, neigh->eid))
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goto cancel;
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if (nla_put(skb, NDA_LLADDR, dev->addr_len, neigh->ha))
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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_rtm_getneigh(struct sk_buff *skb, struct netlink_callback *cb)
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{
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struct net *net = sock_net(skb->sk);
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int rc, idx, req_ifindex;
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struct mctp_neigh *neigh;
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struct ndmsg *ndmsg;
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struct {
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int idx;
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} *cbctx = (void *)cb->ctx;
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ndmsg = nlmsg_data(cb->nlh);
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req_ifindex = ndmsg->ndm_ifindex;
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idx = 0;
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rcu_read_lock();
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list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) {
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if (idx < cbctx->idx)
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goto cont;
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rc = 0;
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if (req_ifindex == 0 || req_ifindex == neigh->dev->dev->ifindex)
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rc = mctp_fill_neigh(skb, NETLINK_CB(cb->skb).portid,
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cb->nlh->nlmsg_seq,
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RTM_NEWNEIGH, NLM_F_MULTI, neigh);
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if (rc)
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break;
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cont:
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idx++;
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}
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rcu_read_unlock();
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cbctx->idx = idx;
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return skb->len;
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}
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int mctp_neigh_lookup(struct mctp_dev *mdev, mctp_eid_t eid, void *ret_hwaddr)
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{
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struct net *net = dev_net(mdev->dev);
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struct mctp_neigh *neigh;
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int rc = -EHOSTUNREACH; // TODO: or ENOENT?
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rcu_read_lock();
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list_for_each_entry_rcu(neigh, &net->mctp.neighbours, list) {
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if (mdev == neigh->dev && eid == neigh->eid) {
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if (ret_hwaddr)
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memcpy(ret_hwaddr, neigh->ha,
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sizeof(neigh->ha));
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rc = 0;
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break;
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}
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}
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rcu_read_unlock();
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return rc;
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}
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/* namespace registration */
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static int __net_init mctp_neigh_net_init(struct net *net)
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{
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struct netns_mctp *ns = &net->mctp;
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INIT_LIST_HEAD(&ns->neighbours);
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mutex_init(&ns->neigh_lock);
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return 0;
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}
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static void __net_exit mctp_neigh_net_exit(struct net *net)
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{
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struct netns_mctp *ns = &net->mctp;
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struct mctp_neigh *neigh;
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list_for_each_entry(neigh, &ns->neighbours, list)
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call_rcu(&neigh->rcu, __mctp_neigh_free);
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}
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/* net namespace implementation */
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static struct pernet_operations mctp_net_ops = {
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.init = mctp_neigh_net_init,
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.exit = mctp_neigh_net_exit,
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};
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int __init mctp_neigh_init(void)
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{
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rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_NEWNEIGH,
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mctp_rtm_newneigh, NULL, 0);
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rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_DELNEIGH,
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mctp_rtm_delneigh, NULL, 0);
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rtnl_register_module(THIS_MODULE, PF_MCTP, RTM_GETNEIGH,
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NULL, mctp_rtm_getneigh, 0);
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return register_pernet_subsys(&mctp_net_ops);
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}
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void __exit mctp_neigh_exit(void)
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{
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unregister_pernet_subsys(&mctp_net_ops);
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rtnl_unregister(PF_MCTP, RTM_GETNEIGH);
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rtnl_unregister(PF_MCTP, RTM_DELNEIGH);
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rtnl_unregister(PF_MCTP, RTM_NEWNEIGH);
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}
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