datagram.c revision bc3b2d7fb9b014d75ebb79ba371a763dbab5e8cf 
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 <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	struct sockaddr_pn *target;
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 (msg->msg_name == NULL)
98		return -EDESTADDRREQ;
99
100	if (msg->msg_namelen < sizeof(struct sockaddr_pn))
101		return -EINVAL;
102
103	target = (struct sockaddr_pn *)msg->msg_name;
104	if (target->spn_family != AF_PHONET)
105		return -EAFNOSUPPORT;
106
107	skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
108					msg->msg_flags & MSG_DONTWAIT, &err);
109	if (skb == NULL)
110		return err;
111	skb_reserve(skb, MAX_PHONET_HEADER);
112
113	err = memcpy_fromiovec((void *)skb_put(skb, len), msg->msg_iov, len);
114	if (err < 0) {
115		kfree_skb(skb);
116		return err;
117	}
118
119	/*
120	 * Fill in the Phonet header and
121	 * finally pass the packet forwards.
122	 */
123	err = pn_skb_send(sk, skb, target);
124
125	/* If ok, return len. */
126	return (err >= 0) ? len : err;
127}
128
129static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
130			struct msghdr *msg, size_t len, int noblock,
131			int flags, int *addr_len)
132{
133	struct sk_buff *skb = NULL;
134	struct sockaddr_pn sa;
135	int rval = -EOPNOTSUPP;
136	int copylen;
137
138	if (flags & ~(MSG_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_NOSIGNAL|
139			MSG_CMSG_COMPAT))
140		goto out_nofree;
141
142	if (addr_len)
143		*addr_len = sizeof(sa);
144
145	skb = skb_recv_datagram(sk, flags, noblock, &rval);
146	if (skb == NULL)
147		goto out_nofree;
148
149	pn_skb_get_src_sockaddr(skb, &sa);
150
151	copylen = skb->len;
152	if (len < copylen) {
153		msg->msg_flags |= MSG_TRUNC;
154		copylen = len;
155	}
156
157	rval = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copylen);
158	if (rval) {
159		rval = -EFAULT;
160		goto out;
161	}
162
163	rval = (flags & MSG_TRUNC) ? skb->len : copylen;
164
165	if (msg->msg_name != NULL)
166		memcpy(msg->msg_name, &sa, sizeof(struct sockaddr_pn));
167
168out:
169	skb_free_datagram(sk, skb);
170
171out_nofree:
172	return rval;
173}
174
175/* Queue an skb for a sock. */
176static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
177{
178	int err = sock_queue_rcv_skb(sk, skb);
179
180	if (err < 0)
181		kfree_skb(skb);
182	return err ? NET_RX_DROP : NET_RX_SUCCESS;
183}
184
185/* Module registration */
186static struct proto pn_proto = {
187	.close		= pn_sock_close,
188	.ioctl		= pn_ioctl,
189	.init		= pn_init,
190	.sendmsg	= pn_sendmsg,
191	.recvmsg	= pn_recvmsg,
192	.backlog_rcv	= pn_backlog_rcv,
193	.hash		= pn_sock_hash,
194	.unhash		= pn_sock_unhash,
195	.get_port	= pn_sock_get_port,
196	.obj_size	= sizeof(struct pn_sock),
197	.owner		= THIS_MODULE,
198	.name		= "PHONET",
199};
200
201static struct phonet_protocol pn_dgram_proto = {
202	.ops		= &phonet_dgram_ops,
203	.prot		= &pn_proto,
204	.sock_type	= SOCK_DGRAM,
205};
206
207int __init isi_register(void)
208{
209	return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
210}
211
212void __exit isi_unregister(void)
213{
214	phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
215}
216