[linux.git] / net / phonet / af_phonet.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * File: af_phonet.c
 *
 * Phonet protocols family
 *
 * Copyright (C) 2008 Nokia Corporation.
 *
 * Authors: Sakari Ailus <[email protected]>
 *          Rémi Denis-Courmont
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/unaligned.h>
#include <net/sock.h>

#include <linux/if_phonet.h>
#include <linux/phonet.h>
#include <net/phonet/phonet.h>
#include <net/phonet/pn_dev.h>

/* Transport protocol registration */
static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;

static const struct phonet_protocol *phonet_proto_get(unsigned int protocol)
{
	const struct phonet_protocol *pp;

	if (protocol >= PHONET_NPROTO)
		return NULL;

	rcu_read_lock();
	pp = rcu_dereference(proto_tab[protocol]);
	if (pp && !try_module_get(pp->prot->owner))
		pp = NULL;
	rcu_read_unlock();

	return pp;
}

static inline void phonet_proto_put(const struct phonet_protocol *pp)
{
	module_put(pp->prot->owner);
}

/* protocol family functions */

static int pn_socket_create(struct net *net, struct socket *sock, int protocol,
			    int kern)
{
	struct sock *sk;
	struct pn_sock *pn;
	const struct phonet_protocol *pnp;
	int err;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;

	if (protocol == 0) {
		/* Default protocol selection */
		switch (sock->type) {
		case SOCK_DGRAM:
			protocol = PN_PROTO_PHONET;
			break;
		case SOCK_SEQPACKET:
			protocol = PN_PROTO_PIPE;
			break;
		default:
			return -EPROTONOSUPPORT;
		}
	}

	pnp = phonet_proto_get(protocol);
	if (pnp == NULL &&
	    request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
		pnp = phonet_proto_get(protocol);

	if (pnp == NULL)
		return -EPROTONOSUPPORT;
	if (sock->type != pnp->sock_type) {
		err = -EPROTONOSUPPORT;
		goto out;
	}

	sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot, kern);
	if (sk == NULL) {
		err = -ENOMEM;
		goto out;
	}

	sock_init_data(sock, sk);
	sock->state = SS_UNCONNECTED;
	sock->ops = pnp->ops;
	sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
	sk->sk_protocol = protocol;
	pn = pn_sk(sk);
	pn->sobject = 0;
	pn->dobject = 0;
	pn->resource = 0;
	sk->sk_prot->init(sk);
	err = 0;

out:
	phonet_proto_put(pnp);
	return err;
}

static const struct net_proto_family phonet_proto_family = {
	.family = PF_PHONET,
	.create = pn_socket_create,
	.owner = THIS_MODULE,
};

/* Phonet device header operations */
static int pn_header_create(struct sk_buff *skb, struct net_device *dev,
				unsigned short type, const void *daddr,
				const void *saddr, unsigned int len)
{
	u8 *media = skb_push(skb, 1);

	if (type != ETH_P_PHONET)
		return -1;

	if (!saddr)
		saddr = dev->dev_addr;
	*media = *(const u8 *)saddr;
	return 1;
}

static int pn_header_parse(const struct sk_buff *skb, unsigned char *haddr)
{
	const u8 *media = skb_mac_header(skb);
	*haddr = *media;
	return 1;
}

const struct header_ops phonet_header_ops = {
	.create = pn_header_create,
	.parse = pn_header_parse,
};
EXPORT_SYMBOL(phonet_header_ops);

/*
 * Prepends an ISI header and sends a datagram.
 */
static int pn_send(struct sk_buff *skb, struct net_device *dev,
			u16 dst, u16 src, u8 res)
{
	struct phonethdr *ph;
	int err;

	if (skb->len + 2 > 0xffff /* Phonet length field limit */ ||
	    skb->len + sizeof(struct phonethdr) > dev->mtu) {
		err = -EMSGSIZE;
		goto drop;
	}

	/* Broadcast sending is not implemented */
	if (pn_addr(dst) == PNADDR_BROADCAST) {
		err = -EOPNOTSUPP;
		goto drop;
	}

	skb_reset_transport_header(skb);
	WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
	skb_push(skb, sizeof(struct phonethdr));
	skb_reset_network_header(skb);
	ph = pn_hdr(skb);
	ph->pn_rdev = pn_dev(dst);
	ph->pn_sdev = pn_dev(src);
	ph->pn_res = res;
	ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
	ph->pn_robj = pn_obj(dst);
	ph->pn_sobj = pn_obj(src);

	skb->protocol = htons(ETH_P_PHONET);
	skb->priority = 0;
	skb->dev = dev;

	if (skb->pkt_type == PACKET_LOOPBACK) {
		skb_reset_mac_header(skb);
		skb_orphan(skb);
		err = netif_rx(skb) ? -ENOBUFS : 0;
	} else {
		err = dev_hard_header(skb, dev, ntohs(skb->protocol),
					NULL, NULL, skb->len);
		if (err < 0) {
			err = -EHOSTUNREACH;
			goto drop;
		}
		err = dev_queue_xmit(skb);
		if (unlikely(err > 0))
			err = net_xmit_errno(err);
	}

	return err;
drop:
	kfree_skb(skb);
	return err;
}

static int pn_raw_send(const void *data, int len, struct net_device *dev,
			u16 dst, u16 src, u8 res)
{
	struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
	if (skb == NULL)
		return -ENOMEM;

	if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0)
		skb->pkt_type = PACKET_LOOPBACK;

	skb_reserve(skb, MAX_PHONET_HEADER);
	__skb_put(skb, len);
	skb_copy_to_linear_data(skb, data, len);
	return pn_send(skb, dev, dst, src, res);
}

/*
 * Create a Phonet header for the skb and send it out. Returns
 * non-zero error code if failed. The skb is freed then.
 */
int pn_skb_send(struct sock *sk, struct sk_buff *skb,
		const struct sockaddr_pn *target)
{
	struct net *net = sock_net(sk);
	struct net_device *dev;
	struct pn_sock *pn = pn_sk(sk);
	int err;
	u16 src, dst;
	u8 daddr, saddr, res;

	src = pn->sobject;
	if (target != NULL) {
		dst = pn_sockaddr_get_object(target);
		res = pn_sockaddr_get_resource(target);
	} else {
		dst = pn->dobject;
		res = pn->resource;
	}
	daddr = pn_addr(dst);

	err = -EHOSTUNREACH;
	if (sk->sk_bound_dev_if)
		dev = dev_get_by_index(net, sk->sk_bound_dev_if);
	else if (phonet_address_lookup(net, daddr) == 0) {
		dev = phonet_device_get(net);
		skb->pkt_type = PACKET_LOOPBACK;
	} else if (dst == 0) {
		/* Resource routing (small race until phonet_rcv()) */
		struct sock *sk = pn_find_sock_by_res(net, res);
		if (sk)	{
			sock_put(sk);
			dev = phonet_device_get(net);
			skb->pkt_type = PACKET_LOOPBACK;
		} else
			dev = phonet_route_output(net, daddr);
	} else
		dev = phonet_route_output(net, daddr);

	if (!dev || !(dev->flags & IFF_UP))
		goto drop;

	saddr = phonet_address_get(dev, daddr);
	if (saddr == PN_NO_ADDR)
		goto drop;

	if (!pn_addr(src))
		src = pn_object(saddr, pn_obj(src));

	err = pn_send(skb, dev, dst, src, res);
	dev_put(dev);
	return err;

drop:
	kfree_skb(skb);
	dev_put(dev);
	return err;
}
EXPORT_SYMBOL(pn_skb_send);

/* Do not send an error message in response to an error message */
static inline int can_respond(struct sk_buff *skb)
{
	const struct phonethdr *ph;
	const struct phonetmsg *pm;
	u8 submsg_id;

	if (!pskb_may_pull(skb, 3))
		return 0;

	ph = pn_hdr(skb);
	if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
		return 0;
	if (ph->pn_res == PN_COMMGR) /* indications */
		return 0;

	ph = pn_hdr(skb); /* re-acquires the pointer */
	pm = pn_msg(skb);
	if (pm->pn_msg_id != PN_COMMON_MESSAGE)
		return 1;
	submsg_id = (ph->pn_res == PN_PREFIX)
		? pm->pn_e_submsg_id : pm->pn_submsg_id;
	if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
		pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
		return 1;
	return 0;
}

static int send_obj_unreachable(struct sk_buff *rskb)
{
	const struct phonethdr *oph = pn_hdr(rskb);
	const struct phonetmsg *opm = pn_msg(rskb);
	struct phonetmsg resp;

	memset(&resp, 0, sizeof(resp));
	resp.pn_trans_id = opm->pn_trans_id;
	resp.pn_msg_id = PN_COMMON_MESSAGE;
	if (oph->pn_res == PN_PREFIX) {
		resp.pn_e_res_id = opm->pn_e_res_id;
		resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
		resp.pn_e_orig_msg_id = opm->pn_msg_id;
		resp.pn_e_status = 0;
	} else {
		resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
		resp.pn_orig_msg_id = opm->pn_msg_id;
		resp.pn_status = 0;
	}
	return pn_raw_send(&resp, sizeof(resp), rskb->dev,
				pn_object(oph->pn_sdev, oph->pn_sobj),
				pn_object(oph->pn_rdev, oph->pn_robj),
				oph->pn_res);
}

static int send_reset_indications(struct sk_buff *rskb)
{
	struct phonethdr *oph = pn_hdr(rskb);
	static const u8 data[4] = {
		0x00 /* trans ID */, 0x10 /* subscribe msg */,
		0x00 /* subscription count */, 0x00 /* dummy */
	};

	return pn_raw_send(data, sizeof(data), rskb->dev,
				pn_object(oph->pn_sdev, 0x00),
				pn_object(oph->pn_rdev, oph->pn_robj),
				PN_COMMGR);
}


/* packet type functions */

/*
 * Stuff received packets to associated sockets.
 * On error, returns non-zero and releases the skb.
 */
static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
			struct packet_type *pkttype,
			struct net_device *orig_dev)
{
	struct net *net = dev_net(dev);
	struct phonethdr *ph;
	struct sockaddr_pn sa;
	u16 len;

	skb = skb_share_check(skb, GFP_ATOMIC);
	if (!skb)
		return NET_RX_DROP;

	/* check we have at least a full Phonet header */
	if (!pskb_pull(skb, sizeof(struct phonethdr)))
		goto out;

	/* check that the advertised length is correct */
	ph = pn_hdr(skb);
	len = get_unaligned_be16(&ph->pn_length);
	if (len < 2)
		goto out;
	len -= 2;
	if ((len > skb->len) || pskb_trim(skb, len))
		goto out;
	skb_reset_transport_header(skb);

	pn_skb_get_dst_sockaddr(skb, &sa);

	/* check if this is broadcasted */
	if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) {
		pn_deliver_sock_broadcast(net, skb);
		goto out;
	}

	/* resource routing */
	if (pn_sockaddr_get_object(&sa) == 0) {
		struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource);
		if (sk)
			return sk_receive_skb(sk, skb, 0);
	}

	/* check if we are the destination */
	if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) {
		/* Phonet packet input */
		struct sock *sk = pn_find_sock_by_sa(net, &sa);

		if (sk)
			return sk_receive_skb(sk, skb, 0);

		if (can_respond(skb)) {
			send_obj_unreachable(skb);
			send_reset_indications(skb);
		}
	} else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
		goto out; /* Race between address deletion and loopback */
	else {
		/* Phonet packet routing */
		struct net_device *out_dev;

		out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa));
		if (!out_dev) {
			net_dbg_ratelimited("No Phonet route to %02X\n",
					    pn_sockaddr_get_addr(&sa));
			goto out;
		}

		__skb_push(skb, sizeof(struct phonethdr));
		skb->dev = out_dev;
		if (out_dev == dev) {
			net_dbg_ratelimited("Phonet loop to %02X on %s\n",
					    pn_sockaddr_get_addr(&sa),
					    dev->name);
			goto out_dev;
		}
		/* Some drivers (e.g. TUN) do not allocate HW header space */
		if (skb_cow_head(skb, out_dev->hard_header_len))
			goto out_dev;

		if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL,
					skb->len) < 0)
			goto out_dev;
		dev_queue_xmit(skb);
		dev_put(out_dev);
		return NET_RX_SUCCESS;
out_dev:
		dev_put(out_dev);
	}

out:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static struct packet_type phonet_packet_type __read_mostly = {
	.type = cpu_to_be16(ETH_P_PHONET),
	.func = phonet_rcv,
};

static DEFINE_MUTEX(proto_tab_lock);

int __init_or_module phonet_proto_register(unsigned int protocol,
				const struct phonet_protocol *pp)
{
	int err = 0;

	if (protocol >= PHONET_NPROTO)
		return -EINVAL;

	err = proto_register(pp->prot, 1);
	if (err)
		return err;

	mutex_lock(&proto_tab_lock);
	if (proto_tab[protocol])
		err = -EBUSY;
	else
		rcu_assign_pointer(proto_tab[protocol], pp);
	mutex_unlock(&proto_tab_lock);

	return err;
}
EXPORT_SYMBOL(phonet_proto_register);

void phonet_proto_unregister(unsigned int protocol,
			const struct phonet_protocol *pp)
{
	mutex_lock(&proto_tab_lock);
	BUG_ON(proto_tab[protocol] != pp);
	RCU_INIT_POINTER(proto_tab[protocol], NULL);
	mutex_unlock(&proto_tab_lock);
	synchronize_rcu();
	proto_unregister(pp->prot);
}
EXPORT_SYMBOL(phonet_proto_unregister);

/* Module registration */
static int __init phonet_init(void)
{
	int err;

	err = phonet_device_init();
	if (err)
		return err;

	pn_sock_init();
	err = sock_register(&phonet_proto_family);
	if (err) {
		printk(KERN_ALERT
			"phonet protocol family initialization failed\n");
		goto err_sock;
	}

	dev_add_pack(&phonet_packet_type);
	phonet_sysctl_init();

	err = isi_register();
	if (err)
		goto err;
	return 0;

err:
	phonet_sysctl_exit();
	sock_unregister(PF_PHONET);
	dev_remove_pack(&phonet_packet_type);
err_sock:
	phonet_device_exit();
	return err;
}

static void __exit phonet_exit(void)
{
	isi_unregister();
	phonet_sysctl_exit();
	sock_unregister(PF_PHONET);
	dev_remove_pack(&phonet_packet_type);
	phonet_device_exit();
}

module_init(phonet_init);
module_exit(phonet_exit);
MODULE_DESCRIPTION("Phonet protocol stack for Linux");
MODULE_LICENSE("GPL");
MODULE_ALIAS_NETPROTO(PF_PHONET);
Commit	Line	Data
2b27bdcc	1	// SPDX-License-Identifier: GPL-2.0-only
4b07b3f6 RDC	2	/*
	3	* File: af_phonet.c
	4	*
	5	* Phonet protocols family
	6	*
	7	* Copyright (C) 2008 Nokia Corporation.
	8	*
31fdc555 RDC	9	* Authors: Sakari Ailus <[email protected]>
31fdc555 RDC	10	* Rémi Denis-Courmont
4b07b3f6 RDC	11	*/
	12
	13	#include <linux/kernel.h>
	14	#include <linux/module.h>
5a0e3ad6	15	#include <linux/slab.h>
5f60d5f6	16	#include <linux/unaligned.h>
4b07b3f6 RDC	17	#include <net/sock.h>
	18
	19	#include <linux/if_phonet.h>
	20	#include <linux/phonet.h>
	21	#include <net/phonet/phonet.h>
f8ff6028	22	#include <net/phonet/pn_dev.h>
4b07b3f6	23
566521d6	24	/* Transport protocol registration */
548ec114	25	static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly;
566521d6	26
548ec114	27	static const struct phonet_protocol *phonet_proto_get(unsigned int protocol)
566521d6	28	{
548ec114	29	const struct phonet_protocol *pp;
566521d6 AD	30
	31	if (protocol >= PHONET_NPROTO)
	32	return NULL;
	33
7ed0132f	34	rcu_read_lock();
b2a5decd	35	pp = rcu_dereference(proto_tab[protocol]);
566521d6 AD	36	if (pp && !try_module_get(pp->prot->owner))
566521d6 AD	37	pp = NULL;
7ed0132f	38	rcu_read_unlock();
566521d6 AD	39
	40	return pp;
	41	}
	42
548ec114	43	static inline void phonet_proto_put(const struct phonet_protocol *pp)
566521d6 AD	44	{
	45	module_put(pp->prot->owner);
	46	}
4b07b3f6 RDC	47
	48	/* protocol family functions */
	49
3f378b68 EP	50	static int pn_socket_create(struct net net, struct socket sock, int protocol,
3f378b68 EP	51	int kern)
4b07b3f6	52	{
ba113a94 RDC	53	struct sock *sk;
ba113a94 RDC	54	struct pn_sock *pn;
548ec114	55	const struct phonet_protocol *pnp;
4b07b3f6 RDC	56	int err;
4b07b3f6 RDC	57
4b07b3f6 RDC	58	if (!capable(CAP_SYS_ADMIN))
	59	return -EPERM;
	60
	61	if (protocol == 0) {
	62	/* Default protocol selection */
	63	switch (sock->type) {
	64	case SOCK_DGRAM:
	65	protocol = PN_PROTO_PHONET;
	66	break;
9641458d RDC	67	case SOCK_SEQPACKET:
	68	protocol = PN_PROTO_PIPE;
	69	break;
4b07b3f6 RDC	70	default:
	71	return -EPROTONOSUPPORT;
	72	}
	73	}
	74
	75	pnp = phonet_proto_get(protocol);
25532824 RDC	76	if (pnp == NULL &&
	77	request_module("net-pf-%d-proto-%d", PF_PHONET, protocol) == 0)
	78	pnp = phonet_proto_get(protocol);
95a5afca	79
4b07b3f6 RDC	80	if (pnp == NULL)
	81	return -EPROTONOSUPPORT;
	82	if (sock->type != pnp->sock_type) {
	83	err = -EPROTONOSUPPORT;
	84	goto out;
	85	}
	86
11aa9c28	87	sk = sk_alloc(net, PF_PHONET, GFP_KERNEL, pnp->prot, kern);
ba113a94 RDC	88	if (sk == NULL) {
	89	err = -ENOMEM;
	90	goto out;
	91	}
	92
	93	sock_init_data(sock, sk);
	94	sock->state = SS_UNCONNECTED;
	95	sock->ops = pnp->ops;
	96	sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
	97	sk->sk_protocol = protocol;
	98	pn = pn_sk(sk);
	99	pn->sobject = 0;
a8059512	100	pn->dobject = 0;
ba113a94 RDC	101	pn->resource = 0;
	102	sk->sk_prot->init(sk);
	103	err = 0;
4b07b3f6 RDC	104
	105	out:
	106	phonet_proto_put(pnp);
	107	return err;
	108	}
	109
ec1b4cf7	110	static const struct net_proto_family phonet_proto_family = {
25532824	111	.family = PF_PHONET,
4b07b3f6 RDC	112	.create = pn_socket_create,
	113	.owner = THIS_MODULE,
	114	};
	115
5f77076d RDC	116	/* Phonet device header operations */
	117	static int pn_header_create(struct sk_buff skb, struct net_device dev,
	118	unsigned short type, const void *daddr,
95c96174	119	const void *saddr, unsigned int len)
5f77076d RDC	120	{
	121	u8 *media = skb_push(skb, 1);
	122
	123	if (type != ETH_P_PHONET)
	124	return -1;
	125
	126	if (!saddr)
	127	saddr = dev->dev_addr;
	128	media = (const u8 *)saddr;
	129	return 1;
	130	}
	131
	132	static int pn_header_parse(const struct sk_buff skb, unsigned char haddr)
	133	{
	134	const u8 *media = skb_mac_header(skb);
	135	haddr = media;
	136	return 1;
	137	}
	138
64237470	139	const struct header_ops phonet_header_ops = {
5f77076d RDC	140	.create = pn_header_create,
	141	.parse = pn_header_parse,
	142	};
	143	EXPORT_SYMBOL(phonet_header_ops);
	144
107d0d9b RDC	145	/*
	146	* Prepends an ISI header and sends a datagram.
	147	*/
	148	static int pn_send(struct sk_buff skb, struct net_device dev,
63d57cd6	149	u16 dst, u16 src, u8 res)
107d0d9b RDC	150	{
	151	struct phonethdr *ph;
	152	int err;
	153
ebfe92ca RDC	154	if (skb->len + 2 > 0xffff /* Phonet length field limit */ \|\|
ebfe92ca RDC	155	skb->len + sizeof(struct phonethdr) > dev->mtu) {
107d0d9b RDC	156	err = -EMSGSIZE;
	157	goto drop;
	158	}
	159
18a1166d RDC	160	/* Broadcast sending is not implemented */
	161	if (pn_addr(dst) == PNADDR_BROADCAST) {
	162	err = -EOPNOTSUPP;
	163	goto drop;
	164	}
	165
107d0d9b RDC	166	skb_reset_transport_header(skb);
	167	WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
	168	skb_push(skb, sizeof(struct phonethdr));
	169	skb_reset_network_header(skb);
	170	ph = pn_hdr(skb);
	171	ph->pn_rdev = pn_dev(dst);
	172	ph->pn_sdev = pn_dev(src);
	173	ph->pn_res = res;
	174	ph->pn_length = __cpu_to_be16(skb->len + 2 - sizeof(*ph));
	175	ph->pn_robj = pn_obj(dst);
	176	ph->pn_sobj = pn_obj(src);
	177
	178	skb->protocol = htons(ETH_P_PHONET);
	179	skb->priority = 0;
	180	skb->dev = dev;
	181
aa6c45f3	182	if (skb->pkt_type == PACKET_LOOPBACK) {
107d0d9b	183	skb_reset_mac_header(skb);
107d0d9b	184	skb_orphan(skb);
63d57cd6	185	err = netif_rx(skb) ? -ENOBUFS : 0;
107d0d9b RDC	186	} else {
	187	err = dev_hard_header(skb, dev, ntohs(skb->protocol),
	188	NULL, NULL, skb->len);
	189	if (err < 0) {
	190	err = -EHOSTUNREACH;
	191	goto drop;
	192	}
	193	err = dev_queue_xmit(skb);
b765e84f RDC	194	if (unlikely(err > 0))
b765e84f RDC	195	err = net_xmit_errno(err);
107d0d9b RDC	196	}
	197
	198	return err;
	199	drop:
	200	kfree_skb(skb);
	201	return err;
	202	}
	203
be0c52bf RDC	204	static int pn_raw_send(const void data, int len, struct net_device dev,
	205	u16 dst, u16 src, u8 res)
	206	{
	207	struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
	208	if (skb == NULL)
	209	return -ENOMEM;
	210
aa6c45f3 RDC	211	if (phonet_address_lookup(dev_net(dev), pn_addr(dst)) == 0)
	212	skb->pkt_type = PACKET_LOOPBACK;
	213
be0c52bf RDC	214	skb_reserve(skb, MAX_PHONET_HEADER);
	215	__skb_put(skb, len);
	216	skb_copy_to_linear_data(skb, data, len);
63d57cd6	217	return pn_send(skb, dev, dst, src, res);
be0c52bf RDC	218	}
be0c52bf RDC	219
107d0d9b RDC	220	/*
	221	* Create a Phonet header for the skb and send it out. Returns
	222	* non-zero error code if failed. The skb is freed then.
	223	*/
	224	int pn_skb_send(struct sock sk, struct sk_buff skb,
	225	const struct sockaddr_pn *target)
	226	{
aa6c45f3	227	struct net *net = sock_net(sk);
107d0d9b RDC	228	struct net_device *dev;
	229	struct pn_sock *pn = pn_sk(sk);
	230	int err;
a8059512 RDC	231	u16 src, dst;
	232	u8 daddr, saddr, res;
	233
	234	src = pn->sobject;
	235	if (target != NULL) {
	236	dst = pn_sockaddr_get_object(target);
	237	res = pn_sockaddr_get_resource(target);
	238	} else {
	239	dst = pn->dobject;
	240	res = pn->resource;
	241	}
	242	daddr = pn_addr(dst);
107d0d9b RDC	243
	244	err = -EHOSTUNREACH;
	245	if (sk->sk_bound_dev_if)
aa6c45f3 RDC	246	dev = dev_get_by_index(net, sk->sk_bound_dev_if);
	247	else if (phonet_address_lookup(net, daddr) == 0) {
	248	dev = phonet_device_get(net);
	249	skb->pkt_type = PACKET_LOOPBACK;
c69d4407	250	} else if (dst == 0) {
b6a563b2	251	/* Resource routing (small race until phonet_rcv()) */
c69d4407	252	struct sock *sk = pn_find_sock_by_res(net, res);
b6a563b2 RDC	253	if (sk) {
	254	sock_put(sk);
	255	dev = phonet_device_get(net);
	256	skb->pkt_type = PACKET_LOOPBACK;
	257	} else
	258	dev = phonet_route_output(net, daddr);
aa6c45f3 RDC	259	} else
	260	dev = phonet_route_output(net, daddr);
	261
107d0d9b RDC	262	if (!dev \|\| !(dev->flags & IFF_UP))
	263	goto drop;
	264
	265	saddr = phonet_address_get(dev, daddr);
	266	if (saddr == PN_NO_ADDR)
	267	goto drop;
	268
107d0d9b RDC	269	if (!pn_addr(src))
	270	src = pn_object(saddr, pn_obj(src));
	271
63d57cd6	272	err = pn_send(skb, dev, dst, src, res);
107d0d9b RDC	273	dev_put(dev);
	274	return err;
	275
	276	drop:
	277	kfree_skb(skb);
1160dfa1	278	dev_put(dev);
107d0d9b RDC	279	return err;
	280	}
	281	EXPORT_SYMBOL(pn_skb_send);
	282
be0c52bf RDC	283	/* Do not send an error message in response to an error message */
	284	static inline int can_respond(struct sk_buff *skb)
	285	{
	286	const struct phonethdr *ph;
	287	const struct phonetmsg *pm;
	288	u8 submsg_id;
	289
	290	if (!pskb_may_pull(skb, 3))
	291	return 0;
	292
	293	ph = pn_hdr(skb);
be0c52bf RDC	294	if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
be0c52bf RDC	295	return 0;
c3a90c78 RDC	296	if (ph->pn_res == PN_COMMGR) /* indications */
c3a90c78 RDC	297	return 0;
be0c52bf RDC	298
	299	ph = pn_hdr(skb); /* re-acquires the pointer */
	300	pm = pn_msg(skb);
	301	if (pm->pn_msg_id != PN_COMMON_MESSAGE)
	302	return 1;
	303	submsg_id = (ph->pn_res == PN_PREFIX)
	304	? pm->pn_e_submsg_id : pm->pn_submsg_id;
	305	if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
	306	pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
	307	return 1;
	308	return 0;
	309	}
	310
	311	static int send_obj_unreachable(struct sk_buff *rskb)
	312	{
	313	const struct phonethdr *oph = pn_hdr(rskb);
	314	const struct phonetmsg *opm = pn_msg(rskb);
	315	struct phonetmsg resp;
	316
	317	memset(&resp, 0, sizeof(resp));
	318	resp.pn_trans_id = opm->pn_trans_id;
	319	resp.pn_msg_id = PN_COMMON_MESSAGE;
	320	if (oph->pn_res == PN_PREFIX) {
	321	resp.pn_e_res_id = opm->pn_e_res_id;
	322	resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
	323	resp.pn_e_orig_msg_id = opm->pn_msg_id;
	324	resp.pn_e_status = 0;
	325	} else {
	326	resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
	327	resp.pn_orig_msg_id = opm->pn_msg_id;
	328	resp.pn_status = 0;
	329	}
	330	return pn_raw_send(&resp, sizeof(resp), rskb->dev,
	331	pn_object(oph->pn_sdev, oph->pn_sobj),
	332	pn_object(oph->pn_rdev, oph->pn_robj),
	333	oph->pn_res);
	334	}
	335
	336	static int send_reset_indications(struct sk_buff *rskb)
	337	{
	338	struct phonethdr *oph = pn_hdr(rskb);
	339	static const u8 data[4] = {
	340	0x00 /* trans ID /, 0x10 / subscribe msg */,
	341	0x00 /* subscription count /, 0x00 / dummy */
	342	};
	343
	344	return pn_raw_send(data, sizeof(data), rskb->dev,
	345	pn_object(oph->pn_sdev, 0x00),
c3a90c78 RDC	346	pn_object(oph->pn_rdev, oph->pn_robj),
c3a90c78 RDC	347	PN_COMMGR);
be0c52bf RDC	348	}
	349
	350
4b07b3f6 RDC	351	/* packet type functions */
	352
	353	/*
	354	* Stuff received packets to associated sockets.
	355	* On error, returns non-zero and releases the skb.
	356	*/
	357	static int phonet_rcv(struct sk_buff skb, struct net_device dev,
	358	struct packet_type *pkttype,
	359	struct net_device *orig_dev)
	360	{
4b8f704b	361	struct net *net = dev_net(dev);
4b07b3f6 RDC	362	struct phonethdr *ph;
	363	struct sockaddr_pn sa;
	364	u16 len;
	365
7aaed57c ED	366	skb = skb_share_check(skb, GFP_ATOMIC);
	367	if (!skb)
	368	return NET_RX_DROP;
	369
4b07b3f6 RDC	370	/* check we have at least a full Phonet header */
	371	if (!pskb_pull(skb, sizeof(struct phonethdr)))
	372	goto out;
	373
	374	/* check that the advertised length is correct */
	375	ph = pn_hdr(skb);
	376	len = get_unaligned_be16(&ph->pn_length);
	377	if (len < 2)
	378	goto out;
	379	len -= 2;
	380	if ((len > skb->len) \|\| pskb_trim(skb, len))
	381	goto out;
	382	skb_reset_transport_header(skb);
	383
	384	pn_skb_get_dst_sockaddr(skb, &sa);
4b07b3f6	385
f14001fc RDC	386	/* check if this is broadcasted */
	387	if (pn_sockaddr_get_addr(&sa) == PNADDR_BROADCAST) {
	388	pn_deliver_sock_broadcast(net, skb);
	389	goto out;
	390	}
	391
b6a563b2 RDC	392	/* resource routing */
	393	if (pn_sockaddr_get_object(&sa) == 0) {
	394	struct sock *sk = pn_find_sock_by_res(net, sa.spn_resource);
	395	if (sk)
	396	return sk_receive_skb(sk, skb, 0);
	397	}
	398
4b8f704b	399	/* check if we are the destination */
	400	if (phonet_address_lookup(net, pn_sockaddr_get_addr(&sa)) == 0) {
	401	/* Phonet packet input */
	402	struct sock *sk = pn_find_sock_by_sa(net, &sa);
	403
	404	if (sk)
	405	return sk_receive_skb(sk, skb, 0);
	406
be0c52bf RDC	407	if (can_respond(skb)) {
	408	send_obj_unreachable(skb);
	409	send_reset_indications(skb);
	410	}
86a0a1e5 RDC	411	} else if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
	412	goto out; /* Race between address deletion and loopback */
	413	else {
	414	/* Phonet packet routing */
	415	struct net_device *out_dev;
	416
	417	out_dev = phonet_route_output(net, pn_sockaddr_get_addr(&sa));
	418	if (!out_dev) {
ba7a46f1 JP	419	net_dbg_ratelimited("No Phonet route to %02X\n",
ba7a46f1 JP	420	pn_sockaddr_get_addr(&sa));
86a0a1e5 RDC	421	goto out;
	422	}
	423
	424	__skb_push(skb, sizeof(struct phonethdr));
	425	skb->dev = out_dev;
	426	if (out_dev == dev) {
ba7a46f1 JP	427	net_dbg_ratelimited("Phonet loop to %02X on %s\n",
	428	pn_sockaddr_get_addr(&sa),
	429	dev->name);
86a0a1e5 RDC	430	goto out_dev;
	431	}
	432	/* Some drivers (e.g. TUN) do not allocate HW header space */
	433	if (skb_cow_head(skb, out_dev->hard_header_len))
	434	goto out_dev;
	435
	436	if (dev_hard_header(skb, out_dev, ETH_P_PHONET, NULL, NULL,
	437	skb->len) < 0)
	438	goto out_dev;
	439	dev_queue_xmit(skb);
	440	dev_put(out_dev);
	441	return NET_RX_SUCCESS;
	442	out_dev:
	443	dev_put(out_dev);
be0c52bf	444	}
ba113a94	445
4b07b3f6 RDC	446	out:
	447	kfree_skb(skb);
	448	return NET_RX_DROP;
	449	}
	450
7546dd97	451	static struct packet_type phonet_packet_type __read_mostly = {
09640e63	452	.type = cpu_to_be16(ETH_P_PHONET),
4b07b3f6 RDC	453	.func = phonet_rcv,
	454	};
	455
7ed0132f RDC	456	static DEFINE_MUTEX(proto_tab_lock);
7ed0132f RDC	457
facb4edc	458	int __init_or_module phonet_proto_register(unsigned int protocol,
548ec114	459	const struct phonet_protocol *pp)
4b07b3f6 RDC	460	{
	461	int err = 0;
	462
	463	if (protocol >= PHONET_NPROTO)
	464	return -EINVAL;
	465
	466	err = proto_register(pp->prot, 1);
	467	if (err)
	468	return err;
	469
7ed0132f	470	mutex_lock(&proto_tab_lock);
4b07b3f6 RDC	471	if (proto_tab[protocol])
	472	err = -EBUSY;
	473	else
cf778b00	474	rcu_assign_pointer(proto_tab[protocol], pp);
7ed0132f	475	mutex_unlock(&proto_tab_lock);
4b07b3f6 RDC	476
	477	return err;
	478	}
	479	EXPORT_SYMBOL(phonet_proto_register);
	480
548ec114 LZ	481	void phonet_proto_unregister(unsigned int protocol,
548ec114 LZ	482	const struct phonet_protocol *pp)
4b07b3f6	483	{
7ed0132f	484	mutex_lock(&proto_tab_lock);
4b07b3f6	485	BUG_ON(proto_tab[protocol] != pp);
a9b3cd7f	486	RCU_INIT_POINTER(proto_tab[protocol], NULL);
7ed0132f RDC	487	mutex_unlock(&proto_tab_lock);
7ed0132f RDC	488	synchronize_rcu();
4b07b3f6 RDC	489	proto_unregister(pp->prot);
	490	}
	491	EXPORT_SYMBOL(phonet_proto_unregister);
	492
4b07b3f6 RDC	493	/* Module registration */
	494	static int __init phonet_init(void)
	495	{
	496	int err;
	497
76e02cf6	498	err = phonet_device_init();
	499	if (err)
	500	return err;
	501
6b0d07ba	502	pn_sock_init();
4b07b3f6 RDC	503	err = sock_register(&phonet_proto_family);
	504	if (err) {
	505	printk(KERN_ALERT
	506	"phonet protocol family initialization failed\n");
76e02cf6	507	goto err_sock;
4b07b3f6 RDC	508	}
	509
	510	dev_add_pack(&phonet_packet_type);
87ab4e20	511	phonet_sysctl_init();
107d0d9b RDC	512
	513	err = isi_register();
	514	if (err)
	515	goto err;
4b07b3f6	516	return 0;
107d0d9b RDC	517
107d0d9b RDC	518	err:
87ab4e20	519	phonet_sysctl_exit();
25532824	520	sock_unregister(PF_PHONET);
107d0d9b	521	dev_remove_pack(&phonet_packet_type);
76e02cf6	522	err_sock:
107d0d9b RDC	523	phonet_device_exit();
107d0d9b RDC	524	return err;
4b07b3f6 RDC	525	}
	526
	527	static void __exit phonet_exit(void)
	528	{
107d0d9b	529	isi_unregister();
87ab4e20	530	phonet_sysctl_exit();
25532824	531	sock_unregister(PF_PHONET);
4b07b3f6	532	dev_remove_pack(&phonet_packet_type);
f8ff6028	533	phonet_device_exit();
4b07b3f6 RDC	534	}
	535
	536	module_init(phonet_init);
	537	module_exit(phonet_exit);
	538	MODULE_DESCRIPTION("Phonet protocol stack for Linux");
	539	MODULE_LICENSE("GPL");
25532824	540	MODULE_ALIAS_NETPROTO(PF_PHONET);