mctp: Add base socket/protocol definitions

 * Copyright (c) 2021 Google

 */

#include <linux/net.h>

#include <linux/mctp.h>

#include <linux/module.h>

#include <linux/socket.h>

#include <net/sock.h>

struct mctp_sock {

	struct sock	sk;

};

static int mctp_release(struct socket *sock)

{

	struct sock *sk = sock->sk;

	if (sk) {

		sock->sk = NULL;

		sk->sk_prot->close(sk, 0);

	}

	return 0;

}

static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen)

{

	return 0;

}

static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)

{

	return 0;

}

static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,

			int flags)

{

	return 0;

}

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

			   sockptr_t optval, unsigned int optlen)

{

	return -EINVAL;

}

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

			   char __user *optval, int __user *optlen)

{

	return -EINVAL;

}

static const struct proto_ops mctp_dgram_ops = {

	.family		= PF_MCTP,

	.release	= mctp_release,

	.bind		= mctp_bind,

	.connect	= sock_no_connect,

	.socketpair	= sock_no_socketpair,

	.accept		= sock_no_accept,

	.getname	= sock_no_getname,

	.poll		= datagram_poll,

	.ioctl		= sock_no_ioctl,

	.gettstamp	= sock_gettstamp,

	.listen		= sock_no_listen,

	.shutdown	= sock_no_shutdown,

	.setsockopt	= mctp_setsockopt,

	.getsockopt	= mctp_getsockopt,

	.sendmsg	= mctp_sendmsg,

	.recvmsg	= mctp_recvmsg,

	.mmap		= sock_no_mmap,

	.sendpage	= sock_no_sendpage,

};

static void mctp_sk_close(struct sock *sk, long timeout)

{

	sk_common_release(sk);

}

static struct proto mctp_proto = {

	.name		= "MCTP",

	.owner		= THIS_MODULE,

	.obj_size	= sizeof(struct mctp_sock),

	.close		= mctp_sk_close,

};

static int mctp_pf_create(struct net *net, struct socket *sock,

			  int protocol, int kern)

{

	const struct proto_ops *ops;

	struct proto *proto;

	struct sock *sk;

	int rc;

	if (protocol)

		return -EPROTONOSUPPORT;

	/* only datagram sockets are supported */

	if (sock->type != SOCK_DGRAM)

		return -ESOCKTNOSUPPORT;

	proto = &mctp_proto;

	ops = &mctp_dgram_ops;

	sock->state = SS_UNCONNECTED;

	sock->ops = ops;

	sk = sk_alloc(net, PF_MCTP, GFP_KERNEL, proto, kern);

	if (!sk)

		return -ENOMEM;

	sock_init_data(sock, sk);

	rc = 0;

	if (sk->sk_prot->init)

		rc = sk->sk_prot->init(sk);

	if (rc)

		goto err_sk_put;

	return 0;

err_sk_put:

	sock_orphan(sk);

	sock_put(sk);

	return rc;

}

static struct net_proto_family mctp_pf = {

	.family = PF_MCTP,

	.create = mctp_pf_create,

	.owner = THIS_MODULE,

};

static __init int mctp_init(void)

{

	int rc;

	pr_info("mctp: management component transport protocol core\n");

	rc = sock_register(&mctp_pf);

	if (rc)

		return rc;

	rc = proto_register(&mctp_proto, 0);

	if (rc)

		goto err_unreg_sock;

	return 0;

err_unreg_sock:

	sock_unregister(PF_MCTP);

	return rc;

}

static __exit void mctp_exit(void)

{

	proto_unregister(&mctp_proto);

	sock_unregister(PF_MCTP);

}

module_init(mctp_init);

module_exit(mctp_exit);

MODULE_DESCRIPTION("MCTP core");

MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Jeremy Kerr <jk@codeconstruct.com.au>");

MODULE_ALIAS_NETPROTO(PF_MCTP);