Commit 99ce45d5 authored by Jeremy Kerr's avatar Jeremy Kerr Committed by David S. Miller
Browse files

mctp: Implement extended addressing 



This change allows an extended address struct - struct sockaddr_mctp_ext
- to be passed to sendmsg/recvmsg. This allows userspace to specify
output ifindex and physical address information (for sendmsg) or receive
the input ifindex/physaddr for incoming messages (for recvmsg). This is
typically used by userspace for MCTP address discovery and assignment
operations.

The extended addressing facility is conditional on a new sockopt:
MCTP_OPT_ADDR_EXT; userspace must explicitly enable addressing before
the kernel will consume/populate the extended address data.

Includes a fix for an uninitialised var:
Reported-by: default avatarkernel test robot <lkp@intel.com>

Signed-off-by: default avatarJeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 971f5c40

include/linux/socket.h

+1 −0
Original line number Diff line number Diff line
@@ -365,6 +365,7 @@ struct ucred { 
#define SOL_TLS		282

#define SOL_XDP		283

#define SOL_MPTCP	284

#define SOL_MCTP	285



/* IPX options */

#define IPX_TYPE	1

include/net/mctp.h

+9 −4
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


#include <linux/bits.h>

#include <linux/mctp.h>

#include <linux/netdevice.h>

#include <net/net_namespace.h>

#include <net/sock.h>
@@ -58,6 +59,9 @@ struct mctp_sock { 
	mctp_eid_t	bind_addr;

	__u8		bind_type;



	/* sendmsg()/recvmsg() uses struct sockaddr_mctp_ext */

	bool		addr_ext;



	/* list of mctp_sk_key, for incoming tag lookup. updates protected

	 * by sk->net->keys_lock

	 */
@@ -153,7 +157,10 @@ struct mctp_sk_key { 
struct mctp_skb_cb {

	unsigned int	magic;

	unsigned int	net;

	int		ifindex; /* extended/direct addressing if set */

	mctp_eid_t	src;

	unsigned char	halen;

	unsigned char	haddr[MAX_ADDR_LEN];

};



/* skb control-block accessors with a little extra debugging for initial
@@ -177,6 +184,7 @@ static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb) 
{

	struct mctp_skb_cb *cb = (void *)skb->cb;



	BUILD_BUG_ON(sizeof(struct mctp_skb_cb) > sizeof(skb->cb));

	WARN_ON(cb->magic != 0x4d435450);

	return (void *)(skb->cb);

}
@@ -189,8 +197,7 @@ static inline struct mctp_skb_cb *mctp_cb(struct sk_buff *skb) 
 *

 * Updates to the route table are performed under rtnl; all reads under RCU,

 * so routes cannot be referenced over a RCU grace period. Specifically: A

 * caller cannot block between mctp_route_lookup and passing the route to

 * mctp_do_route.

 * caller cannot block between mctp_route_lookup and mctp_route_release()

 */

struct mctp_route {

	mctp_eid_t		min, max;
@@ -210,8 +217,6 @@ struct mctp_route { 
struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,

				     mctp_eid_t daddr);



int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb);



int mctp_local_output(struct sock *sk, struct mctp_route *rt,

		      struct sk_buff *skb, mctp_eid_t daddr, u8 req_tag);

include/uapi/linux/mctp.h

+11 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


#include <linux/types.h>

#include <linux/socket.h>

#include <linux/netdevice.h>



typedef __u8			mctp_eid_t;
@@ -28,6 +29,14 @@ struct sockaddr_mctp { 
	__u8			__smctp_pad1;

};



struct sockaddr_mctp_ext {

	struct sockaddr_mctp	smctp_base;

	int			smctp_ifindex;

	__u8			smctp_halen;

	__u8			__smctp_pad0[3];

	__u8			smctp_haddr[MAX_ADDR_LEN];

};



#define MCTP_NET_ANY		0x0



#define MCTP_ADDR_NULL		0x00
@@ -36,4 +45,6 @@ struct sockaddr_mctp { 
#define MCTP_TAG_MASK		0x07

#define MCTP_TAG_OWNER		0x08



#define MCTP_OPT_ADDR_EXT	1



#endif /* __UAPI_MCTP_H */

net/mctp/af_mctp.c

+76 −10
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
	const int hlen = MCTP_HEADER_MAXLEN + sizeof(struct mctp_hdr);

	int rc, addrlen = msg->msg_namelen;

	struct sock *sk = sock->sk;

	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);

	struct mctp_skb_cb *cb;

	struct mctp_route *rt;

	struct sk_buff *skb;
@@ -100,11 +101,6 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
	if (addr->smctp_network == MCTP_NET_ANY)

		addr->smctp_network = mctp_default_net(sock_net(sk));



	rt = mctp_route_lookup(sock_net(sk), addr->smctp_network,

			       addr->smctp_addr.s_addr);

	if (!rt)

		return -EHOSTUNREACH;



	skb = sock_alloc_send_skb(sk, hlen + 1 + len,

				  msg->msg_flags & MSG_DONTWAIT, &rc);

	if (!skb)
@@ -116,19 +112,45 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
	*(u8 *)skb_put(skb, 1) = addr->smctp_type;



	rc = memcpy_from_msg((void *)skb_put(skb, len), msg, len);

	if (rc < 0) {

		kfree_skb(skb);

		return rc;

	}

	if (rc < 0)

		goto err_free;



	/* set up cb */

	cb = __mctp_cb(skb);

	cb->net = addr->smctp_network;



	/* direct addressing */

	if (msk->addr_ext && addrlen >= sizeof(struct sockaddr_mctp_ext)) {

		DECLARE_SOCKADDR(struct sockaddr_mctp_ext *,

				 extaddr, msg->msg_name);



		if (extaddr->smctp_halen > sizeof(cb->haddr)) {

			rc = -EINVAL;

			goto err_free;

		}



		cb->ifindex = extaddr->smctp_ifindex;

		cb->halen = extaddr->smctp_halen;

		memcpy(cb->haddr, extaddr->smctp_haddr, cb->halen);



		rt = NULL;

	} else {

		rt = mctp_route_lookup(sock_net(sk), addr->smctp_network,

				       addr->smctp_addr.s_addr);

		if (!rt) {

			rc = -EHOSTUNREACH;

			goto err_free;

		}

	}



	rc = mctp_local_output(sk, rt, skb, addr->smctp_addr.s_addr,

			       addr->smctp_tag);



	return rc ? : len;



err_free:

	kfree_skb(skb);

	return rc;

}



static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
@@ -136,6 +158,7 @@ static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 
{

	DECLARE_SOCKADDR(struct sockaddr_mctp *, addr, msg->msg_name);

	struct sock *sk = sock->sk;

	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);

	struct sk_buff *skb;

	size_t msglen;

	u8 type;
@@ -181,6 +204,16 @@ static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 
		addr->smctp_tag = hdr->flags_seq_tag &

					(MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);

		msg->msg_namelen = sizeof(*addr);



		if (msk->addr_ext) {

			DECLARE_SOCKADDR(struct sockaddr_mctp_ext *, ae,

					 msg->msg_name);

			msg->msg_namelen = sizeof(*ae);

			ae->smctp_ifindex = cb->ifindex;

			ae->smctp_halen = cb->halen;

			memset(ae->smctp_haddr, 0x0, sizeof(ae->smctp_haddr));

			memcpy(ae->smctp_haddr, cb->haddr, cb->halen);

		}

	}



	rc = len;
@@ -196,12 +229,45 @@ static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 
static int mctp_setsockopt(struct socket *sock, int level, int optname,

			   sockptr_t optval, unsigned int optlen)

{

	struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk);

	int val;



	if (level != SOL_MCTP)

		return -EINVAL;



	if (optname == MCTP_OPT_ADDR_EXT) {

		if (optlen != sizeof(int))

			return -EINVAL;

		if (copy_from_sockptr(&val, optval, sizeof(int)))

			return -EFAULT;

		msk->addr_ext = val;

		return 0;

	}



	return -ENOPROTOOPT;

}



static int mctp_getsockopt(struct socket *sock, int level, int optname,

			   char __user *optval, int __user *optlen)

{

	struct mctp_sock *msk = container_of(sock->sk, struct mctp_sock, sk);

	int len, val;



	if (level != SOL_MCTP)

		return -EINVAL;



	if (get_user(len, optlen))

		return -EFAULT;



	if (optname == MCTP_OPT_ADDR_EXT) {

		if (len != sizeof(int))

			return -EINVAL;

		val = !!msk->addr_ext;

		if (copy_to_user(optval, &val, len))

			return -EFAULT;

		return 0;

	}



	return -EINVAL;

}

net/mctp/route.c

+73 −25
Original line number Diff line number Diff line
@@ -434,6 +434,7 @@ static unsigned int mctp_route_mtu(struct mctp_route *rt) 


static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb)

{

	struct mctp_skb_cb *cb = mctp_cb(skb);

	struct mctp_hdr *hdr = mctp_hdr(skb);

	char daddr_buf[MAX_ADDR_LEN];

	char *daddr = NULL;
@@ -448,9 +449,14 @@ static int mctp_route_output(struct mctp_route *route, struct sk_buff *skb) 
		return -EMSGSIZE;

	}



	if (cb->ifindex) {

		/* direct route; use the hwaddr we stashed in sendmsg */

		daddr = cb->haddr;

	} else {

		/* If lookup fails let the device handle daddr==NULL */

		if (mctp_neigh_lookup(route->dev, hdr->dest, daddr_buf) == 0)

			daddr = daddr_buf;

	}



	rc = dev_hard_header(skb, skb->dev, ntohs(skb->protocol),

			     daddr, skb->dev->dev_addr, skb->len);
@@ -649,16 +655,6 @@ static struct mctp_route *mctp_route_lookup_null(struct net *net, 
	return NULL;

}



/* sends a skb to rt and releases the route. */

int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb)

{

	int rc;



	rc = rt->output(rt, skb);

	mctp_route_release(rt);

	return rc;

}



static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,

				  unsigned int mtu, u8 tag)

{
@@ -725,7 +721,7 @@ static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb, 
		/* copy message payload */

		skb_copy_bits(skb, pos, skb_transport_header(skb2), size);



		/* do route, but don't drop the rt reference */

		/* do route */

		rc = rt->output(rt, skb2);

		if (rc)

			break;
@@ -734,7 +730,6 @@ static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb, 
		pos += size;

	}



	mctp_route_release(rt);

	consume_skb(skb);

	return rc;

}
@@ -744,15 +739,51 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt, 
{

	struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);

	struct mctp_skb_cb *cb = mctp_cb(skb);

	struct mctp_route tmp_rt;

	struct net_device *dev;

	struct mctp_hdr *hdr;

	unsigned long flags;

	unsigned int mtu;

	mctp_eid_t saddr;

	bool ext_rt;

	int rc;

	u8 tag;



	rc = -ENODEV;



	if (rt) {

		ext_rt = false;

		dev = NULL;



		if (WARN_ON(!rt->dev))

			goto out_release;



	} else if (cb->ifindex) {

		ext_rt = true;

		rt = &tmp_rt;



		rcu_read_lock();

		dev = dev_get_by_index_rcu(sock_net(sk), cb->ifindex);

		if (!dev) {

			rcu_read_unlock();

			return rc;

		}



		rt->dev = __mctp_dev_get(dev);

		rcu_read_unlock();



		if (!rt->dev)

			goto out_release;



		/* establish temporary route - we set up enough to keep

		 * mctp_route_output happy

		 */

		rt->output = mctp_route_output;

		rt->mtu = 0;



	} else {

		return -EINVAL;

	}



	spin_lock_irqsave(&rt->dev->addrs_lock, flags);

	if (rt->dev->num_addrs == 0) {
@@ -765,18 +796,17 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt, 
	spin_unlock_irqrestore(&rt->dev->addrs_lock, flags);



	if (rc)

		return rc;

		goto out_release;



	if (req_tag & MCTP_HDR_FLAG_TO) {

		rc = mctp_alloc_local_tag(msk, saddr, daddr, &tag);

		if (rc)

			return rc;

			goto out_release;

		tag |= MCTP_HDR_FLAG_TO;

	} else {

		tag = req_tag;

	}





	skb->protocol = htons(ETH_P_MCTP);

	skb->priority = 0;

	skb_reset_transport_header(skb);
@@ -796,12 +826,22 @@ int mctp_local_output(struct sock *sk, struct mctp_route *rt, 
	mtu = mctp_route_mtu(rt);



	if (skb->len + sizeof(struct mctp_hdr) <= mtu) {

		hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM |

			tag;

		return mctp_do_route(rt, skb);

		hdr->flags_seq_tag = MCTP_HDR_FLAG_SOM |

			MCTP_HDR_FLAG_EOM | tag;

		rc = rt->output(rt, skb);

	} else {

		return mctp_do_fragment_route(rt, skb, mtu, tag);

		rc = mctp_do_fragment_route(rt, skb, mtu, tag);

	}



out_release:

	if (!ext_rt)

		mctp_route_release(rt);



	if (dev)

		dev_put(dev);



	return rc;



}



/* route management */
@@ -942,8 +982,15 @@ static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev, 
	if (mh->ver < MCTP_VER_MIN || mh->ver > MCTP_VER_MAX)

		goto err_drop;



	/* MCTP drivers must populate halen/haddr */

	if (dev->type == ARPHRD_MCTP) {

		cb = mctp_cb(skb);

	} else {

		cb = __mctp_cb(skb);

		cb->halen = 0;

	}

	cb->net = READ_ONCE(mdev->net);

	cb->ifindex = dev->ifindex;



	rt = mctp_route_lookup(net, cb->net, mh->dest);
@@ -954,7 +1001,8 @@ static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev, 
	if (!rt)

		goto err_drop;



	mctp_do_route(rt, skb);

	rt->output(rt, skb);

	mctp_route_release(rt);



	return NET_RX_SUCCESS;