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mctp: Add device handling and netlink interface

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This change adds the infrastructure for managing MCTP netdevices; we add
a pointer to the AF_MCTP-specific data to struct netdevice, and hook up
the rtnetlink operations for adding and removing addresses.

Includes changes from Matt Johnston <matt@codeconstruct.com.au>.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jeremy Kerr 2021-07-29 10:20:44 +08:00 committed by David S. Miller
parent 4b2e69305c
commit 583be982d9
10 changed files with 491 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
MAINTAINERS
View File

@ -11039,6 +11039,7 @@ L: netdev@vger.kernel.org
S: Maintained
F: drivers/net/mctp/
F: include/net/mctp.h
F: include/net/mctpdevice.h
F: net/mctp/
MAN-PAGES: MANUAL PAGES FOR LINUX -- Sections 2, 3, 4, 5, and 7

4
include/linux/netdevice.h
View File

@ -1823,6 +1823,7 @@ enum netdev_ml_priv_type {
* @ieee802154_ptr: IEEE 802.15.4 low-rate Wireless Personal Area Network
* device struct
* @mpls_ptr: mpls_dev struct pointer
* @mctp_ptr: MCTP specific data
*
* @dev_addr: Hw address (before bcast,
* because most packets are unicast)
@ -2110,6 +2111,9 @@ struct net_device {
#if IS_ENABLED(CONFIG_MPLS_ROUTING)
struct mpls_dev __rcu *mpls_ptr;
#endif
#if IS_ENABLED(CONFIG_MCTP)
struct mctp_dev __rcu *mctp_ptr;
#endif
/*
* Cache lines mostly used on receive path (including eth_type_trans())

14
include/net/mctp.h
View File

@ -10,6 +10,7 @@
#define __NET_MCTP_H
#include <linux/bits.h>
#include <linux/mctp.h>
/* MCTP packet definitions */
struct mctp_hdr {
@ -32,4 +33,17 @@ struct mctp_hdr {
#define MCTP_HDR_TAG_SHIFT 0
#define MCTP_HDR_TAG_MASK GENMASK(2, 0)
static inline bool mctp_address_ok(mctp_eid_t eid)
{
return eid >= 8 && eid < 255;
}
static inline struct mctp_hdr *mctp_hdr(struct sk_buff *skb)
{
return (struct mctp_hdr *)skb_network_header(skb);
}
void mctp_device_init(void);
void mctp_device_exit(void);
#endif /* __NET_MCTP_H */

35
include/net/mctpdevice.h Normal file
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@ -0,0 +1,35 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Management Component Transport Protocol (MCTP) - device
* definitions.
*
* Copyright (c) 2021 Code Construct
* Copyright (c) 2021 Google
*/
#ifndef __NET_MCTPDEVICE_H
#define __NET_MCTPDEVICE_H
#include <linux/list.h>
#include <linux/types.h>
#include <linux/refcount.h>
struct mctp_dev {
struct net_device *dev;
unsigned int net;
/* Only modified under RTNL. Reads have addrs_lock held */
u8 *addrs;
size_t num_addrs;
spinlock_t addrs_lock;
struct rcu_head rcu;
};
#define MCTP_INITIAL_DEFAULT_NET 1
struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev);
struct mctp_dev *__mctp_dev_get(const struct net_device *dev);
#endif /* __NET_MCTPDEVICE_H */

3
include/uapi/linux/if_ether.h
View File

@ -151,6 +151,9 @@
#define ETH_P_MAP 0x00F9 /* Qualcomm multiplexing and
* aggregation protocol
*/
#define ETH_P_MCTP 0x00FA /* Management component transport
* protocol packets
*/
/*
* This is an Ethernet frame header.

10
include/uapi/linux/if_link.h
View File

@ -1260,4 +1260,14 @@ struct ifla_rmnet_flags {
__u32 mask;
};
/* MCTP section */
enum {
IFLA_MCTP_UNSPEC,
IFLA_MCTP_NET,
__IFLA_MCTP_MAX,
};
#define IFLA_MCTP_MAX (__IFLA_MCTP_MAX - 1)
#endif /* _UAPI_LINUX_IF_LINK_H */

1
include/uapi/linux/mctp.h
View File

@ -26,6 +26,7 @@ struct sockaddr_mctp {
};
#define MCTP_NET_ANY 0x0
#define MCTP_NET_DEFAULT 0x0
#define MCTP_ADDR_NULL 0x00
#define MCTP_ADDR_ANY 0xff

2
net/mctp/Makefile
View File

@ -1,3 +1,3 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_MCTP) += mctp.o
mctp-objs := af_mctp.o
mctp-objs := af_mctp.o device.o

8
net/mctp/af_mctp.c
View File

@ -6,13 +6,18 @@
* Copyright (c) 2021 Google
*/
#include <linux/if_arp.h>
#include <linux/net.h>
#include <linux/mctp.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <net/mctp.h>
#include <net/mctpdevice.h>
#include <net/sock.h>
/* socket implementation */
struct mctp_sock {
struct sock sk;
};
@ -152,6 +157,8 @@ static __init int mctp_init(void)
if (rc)
goto err_unreg_sock;
mctp_device_init();
return 0;
err_unreg_sock:
@ -162,6 +169,7 @@ err_unreg_sock:
static __exit void mctp_exit(void)
{
mctp_device_exit();
proto_unregister(&mctp_proto);
sock_unregister(PF_MCTP);
}

414
net/mctp/device.c Normal file
View File

@ -0,0 +1,414 @@
// 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);
}