datagram.c revision 342dfc306fb32155314dad277f3c3686b83fb9f1 
1/*
2 * File: datagram.c
3 *
4 * Datagram (ISI) Phonet sockets
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Authors: Sakari Ailus <sakari.ailus@nokia.com>
9 *          Rémi Denis-Courmont
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 <linux/export.h>
34#include <net/phonet/phonet.h>
35
36static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb);
37
38/* associated socket ceases to exist */
39static void pn_sock_close(struct sock *sk, long timeout)
40{
41	sk_common_release(sk);
42}
43
44static int pn_ioctl(struct sock *sk, int cmd, unsigned long arg)
45{
46	struct sk_buff *skb;
47	int answ;
48
49	switch (cmd) {
50	case SIOCINQ:
51		lock_sock(sk);
52		skb = skb_peek(&sk->sk_receive_queue);
53		answ = skb ? skb->len : 0;
54		release_sock(sk);
55		return put_user(answ, (int __user *)arg);
56
57	case SIOCPNADDRESOURCE:
58	case SIOCPNDELRESOURCE: {
59			u32 res;
60			if (get_user(res, (u32 __user *)arg))
61				return -EFAULT;
62			if (res >= 256)
63				return -EINVAL;
64			if (cmd == SIOCPNADDRESOURCE)
65				return pn_sock_bind_res(sk, res);
66			else
67				return pn_sock_unbind_res(sk, res);
68		}
69	}
70
71	return -ENOIOCTLCMD;
72}
73
74/* Destroy socket. All references are gone. */
75static void pn_destruct(struct sock *sk)
76{
77	skb_queue_purge(&sk->sk_receive_queue);
78}
79
80static int pn_init(struct sock *sk)
81{
82	sk->sk_destruct = pn_destruct;
83	return 0;
84}
85
86static int pn_sendmsg(struct kiocb *iocb, struct sock *sk,
87			struct msghdr *msg, size_t len)
88{
89	DECLARE_SOCKADDR(struct sockaddr_pn *, target, msg->msg_name);
90	struct sk_buff *skb;
91	int err;
92
93	if (msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL|
94				MSG_CMSG_COMPAT))
95		return -EOPNOTSUPP;
96
97	if (target == NULL)
98		return -EDESTADDRREQ;
99
100	if (msg->msg_namelen < sizeof(struct sockaddr_pn))
101		return -EINVAL;
102
103	if (target->spn_family != AF_PHONET)
104		return -EAFNOSUPPORT;
105
106	skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
107					msg->msg_flags & MSG_DONTWAIT, &err);
108	if (skb == NULL)
109		return err;
110	skb_reserve(skb, MAX_PHONET_HEADER);
111
112	err = memcpy_fromiovec((void *)skb_put(skb, len), msg->msg_iov, len);
113	if (err < 0) {
114		kfree_skb(skb);
115		return err;
116	}
117
118	/*
119	 * Fill in the Phonet header and
120	 * finally pass the packet forwards.
121	 */
122	err = pn_skb_send(sk, skb, target);
123
124	/* If ok, return len. */
125	return (err >= 0) ? len : err;
126}
127
128static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
129			struct msghdr *msg, size_t len, int noblock,
130			int flags, int *addr_len)
131{
132	struct sk_buff *skb = NULL;
133	struct sockaddr_pn sa;
134	int rval = -EOPNOTSUPP;
135	int copylen;
136
137	if (flags & ~(MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_NOSIGNAL|
138			MSG_CMSG_COMPAT))
139		goto out_nofree;
140
141	skb = skb_recv_datagram(sk, flags, noblock, &rval);
142	if (skb == NULL)
143		goto out_nofree;
144
145	pn_skb_get_src_sockaddr(skb, &sa);
146
147	copylen = skb->len;
148	if (len < copylen) {
149		msg->msg_flags |= MSG_TRUNC;
150		copylen = len;
151	}
152
153	rval = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copylen);
154	if (rval) {
155		rval = -EFAULT;
156		goto out;
157	}
158
159	rval = (flags & MSG_TRUNC) ? skb->len : copylen;
160
161	if (msg->msg_name != NULL) {
162		__sockaddr_check_size(sizeof(sa));
163		memcpy(msg->msg_name, &sa, sizeof(sa));
164		*addr_len = sizeof(sa);
165	}
166
167out:
168	skb_free_datagram(sk, skb);
169
170out_nofree:
171	return rval;
172}
173
174/* Queue an skb for a sock. */
175static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
176{
177	int err = sock_queue_rcv_skb(sk, skb);
178
179	if (err < 0)
180		kfree_skb(skb);
181	return err ? NET_RX_DROP : NET_RX_SUCCESS;
182}
183
184/* Module registration */
185static struct proto pn_proto = {
186	.close		= pn_sock_close,
187	.ioctl		= pn_ioctl,
188	.init		= pn_init,
189	.sendmsg	= pn_sendmsg,
190	.recvmsg	= pn_recvmsg,
191	.backlog_rcv	= pn_backlog_rcv,
192	.hash		= pn_sock_hash,
193	.unhash		= pn_sock_unhash,
194	.get_port	= pn_sock_get_port,
195	.obj_size	= sizeof(struct pn_sock),
196	.owner		= THIS_MODULE,
197	.name		= "PHONET",
198};
199
200static struct phonet_protocol pn_dgram_proto = {
201	.ops		= &phonet_dgram_ops,
202	.prot		= &pn_proto,
203	.sock_type	= SOCK_DGRAM,
204};
205
206int __init isi_register(void)
207{
208	return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
209}
210
211void __exit isi_unregister(void)
212{
213	phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
214}
215