1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * File: datagram.c
4  *
5  * Datagram (ISI) Phonet sockets
6  *
7  * Copyright (C) 2008 Nokia Corporation.
8  *
9  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
10  *          Rémi Denis-Courmont
11  */
12 
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/socket.h>
16 #include <asm/ioctls.h>
17 #include <net/sock.h>
18 
19 #include <linux/phonet.h>
20 #include <linux/export.h>
21 #include <net/phonet/phonet.h>
22 
23 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb);
24 
25 /* associated socket ceases to exist */
pn_sock_close(struct sock * sk,long timeout)26 static void pn_sock_close(struct sock *sk, long timeout)
27 {
28 	sk_common_release(sk);
29 }
30 
pn_ioctl(struct sock * sk,int cmd,unsigned long arg)31 static int pn_ioctl(struct sock *sk, int cmd, unsigned long arg)
32 {
33 	struct sk_buff *skb;
34 	int answ;
35 
36 	switch (cmd) {
37 	case SIOCINQ:
38 		lock_sock(sk);
39 		skb = skb_peek(&sk->sk_receive_queue);
40 		answ = skb ? skb->len : 0;
41 		release_sock(sk);
42 		return put_user(answ, (int __user *)arg);
43 
44 	case SIOCPNADDRESOURCE:
45 	case SIOCPNDELRESOURCE: {
46 			u32 res;
47 			if (get_user(res, (u32 __user *)arg))
48 				return -EFAULT;
49 			if (res >= 256)
50 				return -EINVAL;
51 			if (cmd == SIOCPNADDRESOURCE)
52 				return pn_sock_bind_res(sk, res);
53 			else
54 				return pn_sock_unbind_res(sk, res);
55 		}
56 	}
57 
58 	return -ENOIOCTLCMD;
59 }
60 
61 /* Destroy socket. All references are gone. */
pn_destruct(struct sock * sk)62 static void pn_destruct(struct sock *sk)
63 {
64 	skb_queue_purge(&sk->sk_receive_queue);
65 }
66 
pn_init(struct sock * sk)67 static int pn_init(struct sock *sk)
68 {
69 	sk->sk_destruct = pn_destruct;
70 	return 0;
71 }
72 
pn_sendmsg(struct sock * sk,struct msghdr * msg,size_t len)73 static int pn_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
74 {
75 	DECLARE_SOCKADDR(struct sockaddr_pn *, target, msg->msg_name);
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 (target == NULL)
84 		return -EDESTADDRREQ;
85 
86 	if (msg->msg_namelen < sizeof(struct sockaddr_pn))
87 		return -EINVAL;
88 
89 	if (target->spn_family != AF_PHONET)
90 		return -EAFNOSUPPORT;
91 
92 	skb = sock_alloc_send_skb(sk, MAX_PHONET_HEADER + len,
93 					msg->msg_flags & MSG_DONTWAIT, &err);
94 	if (skb == NULL)
95 		return err;
96 	skb_reserve(skb, MAX_PHONET_HEADER);
97 
98 	err = memcpy_from_msg((void *)skb_put(skb, len), msg, len);
99 	if (err < 0) {
100 		kfree_skb(skb);
101 		return err;
102 	}
103 
104 	/*
105 	 * Fill in the Phonet header and
106 	 * finally pass the packet forwards.
107 	 */
108 	err = pn_skb_send(sk, skb, target);
109 
110 	/* If ok, return len. */
111 	return (err >= 0) ? len : err;
112 }
113 
pn_recvmsg(struct sock * sk,struct msghdr * msg,size_t len,int flags,int * addr_len)114 static int pn_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
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_PEEK|MSG_TRUNC|MSG_DONTWAIT|MSG_NOSIGNAL|
123 			MSG_CMSG_COMPAT))
124 		goto out_nofree;
125 
126 	skb = skb_recv_datagram(sk, flags, &rval);
127 	if (skb == NULL)
128 		goto out_nofree;
129 
130 	pn_skb_get_src_sockaddr(skb, &sa);
131 
132 	copylen = skb->len;
133 	if (len < copylen) {
134 		msg->msg_flags |= MSG_TRUNC;
135 		copylen = len;
136 	}
137 
138 	rval = skb_copy_datagram_msg(skb, 0, msg, copylen);
139 	if (rval) {
140 		rval = -EFAULT;
141 		goto out;
142 	}
143 
144 	rval = (flags & MSG_TRUNC) ? skb->len : copylen;
145 
146 	if (msg->msg_name != NULL) {
147 		__sockaddr_check_size(sizeof(sa));
148 		memcpy(msg->msg_name, &sa, sizeof(sa));
149 		*addr_len = sizeof(sa);
150 	}
151 
152 out:
153 	skb_free_datagram(sk, skb);
154 
155 out_nofree:
156 	return rval;
157 }
158 
159 /* Queue an skb for a sock. */
pn_backlog_rcv(struct sock * sk,struct sk_buff * skb)160 static int pn_backlog_rcv(struct sock *sk, struct sk_buff *skb)
161 {
162 	int err = sock_queue_rcv_skb(sk, skb);
163 
164 	if (err < 0)
165 		kfree_skb(skb);
166 	return err ? NET_RX_DROP : NET_RX_SUCCESS;
167 }
168 
169 /* Module registration */
170 static struct proto pn_proto = {
171 	.close		= pn_sock_close,
172 	.ioctl		= pn_ioctl,
173 	.init		= pn_init,
174 	.sendmsg	= pn_sendmsg,
175 	.recvmsg	= pn_recvmsg,
176 	.backlog_rcv	= pn_backlog_rcv,
177 	.hash		= pn_sock_hash,
178 	.unhash		= pn_sock_unhash,
179 	.get_port	= pn_sock_get_port,
180 	.obj_size	= sizeof(struct pn_sock),
181 	.owner		= THIS_MODULE,
182 	.name		= "PHONET",
183 };
184 
185 static const struct phonet_protocol pn_dgram_proto = {
186 	.ops		= &phonet_dgram_ops,
187 	.prot		= &pn_proto,
188 	.sock_type	= SOCK_DGRAM,
189 };
190 
isi_register(void)191 int __init isi_register(void)
192 {
193 	return phonet_proto_register(PN_PROTO_PHONET, &pn_dgram_proto);
194 }
195 
isi_unregister(void)196 void __exit isi_unregister(void)
197 {
198 	phonet_proto_unregister(PN_PROTO_PHONET, &pn_dgram_proto);
199 }
200