datagram.c revision 766e9037cc139ee25ed93ee5ad11e1450c4b99f6 
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/socket.h>
28#include <asm/ioctls.h>
29#include <net/sock.h>
30
31#include <linux/phonet.h>
32#include <net/phonet/phonet.h>
33
34static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb);
35
36/* associated socket ceases to exist */
37static void pn_sock_close(struct sock *sk, long timeout)
38{
39	sk_common_release(sk);
40}
41
42static int pn_ioctl(struct sock *sk, int cmd, unsigned long arg)
43{
44	struct sk_buff *skb;
45	int answ;
46
47	switch (cmd) {
48	case SIOCINQ:
49		lock_sock(sk);
50		skb = skb_peek(&sk->sk_receive_queue);
51		answ = skb ? skb->len : 0;
52		release_sock(sk);
53		return put_user(answ, (int __user *)arg);
54	}
55
56	return -ENOIOCTLCMD;
57}
58
59/* Destroy socket. All references are gone. */
60static void pn_destruct(struct sock *sk)
61{
62	skb_queue_purge(&sk->sk_receive_queue);
63}
64
65static int pn_init(struct sock *sk)
66{
67	sk->sk_destruct = pn_destruct;
68	return 0;
69}
70
71static int pn_sendmsg(struct kiocb *iocb, struct sock *sk,
72			struct msghdr *msg, size_t len)
73{
74	struct sockaddr_pn *target;
75	struct sk_buff *skb;
76	int err;
77
78	if (msg->msg_flags & MSG_OOB)
79		return -EOPNOTSUPP;
80
81	if (msg->msg_name == NULL)
82		return -EDESTADDRREQ;
83
84	if (msg->msg_namelen < sizeof(struct sockaddr_pn))
85		return -EINVAL;
86
87	target = (struct sockaddr_pn *)msg->msg_name;
88	if (target->spn_family != AF_PHONET)
89		return -EAFNOSUPPORT;
90
91	skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
92					msg->msg_flags & MSG_DONTWAIT, &err);
93	if (skb == NULL)
94		return err;
95	skb_reserve(skb, MAX_PHONET_HEADER);
96
97	err = memcpy_fromiovec((void *)skb_put(skb, len), msg->msg_iov, len);
98	if (err < 0) {
99		kfree_skb(skb);
100		return err;
101	}
102
103	/*
104	 * Fill in the Phonet header and
105	 * finally pass the packet forwards.
106	 */
107	err = pn_skb_send(sk, skb, target);
108
109	/* If ok, return len. */
110	return (err >= 0) ? len : err;
111}
112
113static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
114			struct msghdr *msg, size_t len, int noblock,
115			int flags, int *addr_len)
116{
117	struct sk_buff *skb = NULL;
118	struct sockaddr_pn sa;
119	int rval = -EOPNOTSUPP;
120	int copylen;
121
122	if (flags & MSG_OOB)
123		goto out_nofree;
124
125	if (addr_len)
126		*addr_len = sizeof(sa);
127
128	skb = skb_recv_datagram(sk, flags, noblock, &rval);
129	if (skb == NULL)
130		goto out_nofree;
131
132	pn_skb_get_src_sockaddr(skb, &sa);
133
134	copylen = skb->len;
135	if (len < copylen) {
136		msg->msg_flags |= MSG_TRUNC;
137		copylen = len;
138	}
139
140	rval = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copylen);
141	if (rval) {
142		rval = -EFAULT;
143		goto out;
144	}
145
146	rval = (flags & MSG_TRUNC) ? skb->len : copylen;
147
148	if (msg->msg_name != NULL)
149		memcpy(msg->msg_name, &sa, sizeof(struct sockaddr_pn));
150
151out:
152	skb_free_datagram(sk, skb);
153
154out_nofree:
155	return rval;
156}
157
158/* Queue an skb for a sock. */
159static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
160{
161	int err = sock_queue_rcv_skb(sk, skb);
162
163	if (err < 0)
164		kfree_skb(skb);
165	return err ? NET_RX_DROP : NET_RX_SUCCESS;
166}
167
168/* Module registration */
169static struct proto pn_proto = {
170	.close		= pn_sock_close,
171	.ioctl		= pn_ioctl,
172	.init		= pn_init,
173	.sendmsg	= pn_sendmsg,
174	.recvmsg	= pn_recvmsg,
175	.backlog_rcv	= pn_backlog_rcv,
176	.hash		= pn_sock_hash,
177	.unhash		= pn_sock_unhash,
178	.get_port	= pn_sock_get_port,
179	.obj_size	= sizeof(struct pn_sock),
180	.owner		= THIS_MODULE,
181	.name		= "PHONET",
182};
183
184static struct phonet_protocol pn_dgram_proto = {
185	.ops		= &phonet_dgram_ops,
186	.prot		= &pn_proto,
187	.sock_type	= SOCK_DGRAM,
188};
189
190int __init isi_register(void)
191{
192	return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
193}
194
195void __exit isi_unregister(void)
196{
197	phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
198}
199