linux/net/mctp/neigh.c
Jeremy Kerr cb196b7259 mctp: replace mctp_address_ok with more fine-grained helpers
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>
2022-02-18 21:24:28 -08:00

344 lines
7.9 KiB
C

// 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);
}