1/*
2 * File: datagram.c
3 *
4 * Datagram (ISI) Phonet sockets
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
9 * Original author: Sakari Ailus <sakari.ailus@nokia.com>
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * version 2 as published by the Free Software Foundation.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23 * 02110-1301 USA
24 */
25
26#include <linux/kernel.h>
27#include <linux/slab.h>
28#include <linux/socket.h>
29#include <asm/ioctls.h>
30#include <net/sock.h>
31
32#include <linux/phonet.h>
33#include <net/phonet/phonet.h>
34
35static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb);
36
37/* associated socket ceases to exist */
38static void pn_sock_close(struct sock *sk, long timeout)
39{
40	sk_common_release(sk);
41}
42
43static int pn_ioctl(struct sock *sk, int cmd, unsigned long arg)
44{
45	struct sk_buff *skb;
46	int answ;
47
48	switch (cmd) {
49	case SIOCINQ:
50		lock_sock(sk);
51		skb = skb_peek(&sk->sk_receive_queue);
52		answ = skb ? skb->len : 0;
53		release_sock(sk);
54		return put_user(answ, (int __user *)arg);
55	}
56
57	return -ENOIOCTLCMD;
58}
59
60/* Destroy socket. All references are gone. */
61static void pn_destruct(struct sock *sk)
62{
63	skb_queue_purge(&sk->sk_receive_queue);
64}
65
66static int pn_init(struct sock *sk)
67{
68	sk->sk_destruct = pn_destruct;
69	return 0;
70}
71
72static int pn_sendmsg(struct kiocb *iocb, struct sock *sk,
73			struct msghdr *msg, size_t len)
74{
75	struct sockaddr_pn *target;
76	struct sk_buff *skb;
77	int err;
78
79	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|
80				MSG_CMSG_COMPAT))
81		return -EOPNOTSUPP;
82
83	if (msg->msg_name == NULL)
84		return -EDESTADDRREQ;
85
86	if (msg->msg_namelen < sizeof(struct sockaddr_pn))
87		return -EINVAL;
88
89	target = (struct sockaddr_pn *)msg->msg_name;
90	if (target->spn_family != AF_PHONET)
91		return -EAFNOSUPPORT;
92
93	skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
94					msg->msg_flags & MSG_DONTWAIT, &err);
95	if (skb == NULL)
96		return err;
97	skb_reserve(skb, MAX_PHONET_HEADER);
98
99	err = memcpy_fromiovec((void *)skb_put(skb, len), msg->msg_iov, len);
100	if (err < 0) {
101		kfree_skb(skb);
102		return err;
103	}
104
105	/*
106	 * Fill in the Phonet header and
107	 * finally pass the packet forwards.
108	 */
109	err = pn_skb_send(sk, skb, target);
110
111	/* If ok, return len. */
112	return (err >= 0) ? len : err;
113}
114
115static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
116			struct msghdr *msg, size_t len, int noblock,
117			int flags, int *addr_len)
118{
119	struct sk_buff *skb = NULL;
120	struct sockaddr_pn sa;
121	int rval = -EOPNOTSUPP;
122	int copylen;
123
124	if (flags & ~(MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_NOSIGNAL|
125			MSG_CMSG_COMPAT))
126		goto out_nofree;
127
128	if (addr_len)
129		*addr_len = sizeof(sa);
130
131	skb = skb_recv_datagram(sk, flags, noblock, &rval);
132	if (skb == NULL)
133		goto out_nofree;
134
135	pn_skb_get_src_sockaddr(skb, &sa);
136
137	copylen = skb->len;
138	if (len < copylen) {
139		msg->msg_flags |= MSG_TRUNC;
140		copylen = len;
141	}
142
143	rval = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copylen);
144	if (rval) {
145		rval = -EFAULT;
146		goto out;
147	}
148
149	rval = (flags & MSG_TRUNC) ? skb->len : copylen;
150
151	if (msg->msg_name != NULL)
152		memcpy(msg->msg_name, &sa, sizeof(struct sockaddr_pn));
153
154out:
155	skb_free_datagram(sk, skb);
156
157out_nofree:
158	return rval;
159}
160
161/* Queue an skb for a sock. */
162static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
163{
164	int err = sock_queue_rcv_skb(sk, skb);
165
166	if (err < 0)
167		kfree_skb(skb);
168	return err ? NET_RX_DROP : NET_RX_SUCCESS;
169}
170
171/* Module registration */
172static struct proto pn_proto = {
173	.close		= pn_sock_close,
174	.ioctl		= pn_ioctl,
175	.init		= pn_init,
176	.sendmsg	= pn_sendmsg,
177	.recvmsg	= pn_recvmsg,
178	.backlog_rcv	= pn_backlog_rcv,
179	.hash		= pn_sock_hash,
180	.unhash		= pn_sock_unhash,
181	.get_port	= pn_sock_get_port,
182	.obj_size	= sizeof(struct pn_sock),
183	.owner		= THIS_MODULE,
184	.name		= "PHONET",
185};
186
187static struct phonet_protocol pn_dgram_proto = {
188	.ops		= &phonet_dgram_ops,
189	.prot		= &pn_proto,
190	.sock_type	= SOCK_DGRAM,
191};
192
193int __init isi_register(void)
194{
195	return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
196}
197
198void __exit isi_unregister(void)
199{
200	phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
201}
202