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1/*
2 * File: pep-gprs.c
3 *
4 * GPRS over Phonet pipe end point socket
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Author: Rémi Denis-Courmont
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * version 2 as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22 * 02110-1301 USA
23 */
24
25#include <linux/kernel.h>
26#include <linux/netdevice.h>
27#include <linux/if_ether.h>
28#include <linux/if_arp.h>
29#include <net/sock.h>
30
31#include <linux/if_phonet.h>
32#include <net/tcp_states.h>
33#include <net/phonet/gprs.h>
34
35#define GPRS_DEFAULT_MTU 1400
36
37struct gprs_dev {
38 struct sock *sk;
39 void (*old_state_change)(struct sock *);
40 void (*old_data_ready)(struct sock *);
41 void (*old_write_space)(struct sock *);
42
43 struct net_device *dev;
44};
45
46static __be16 gprs_type_trans(struct sk_buff *skb)
47{
48 const u8 *pvfc;
49 u8 buf;
50
51 pvfc = skb_header_pointer(skb, 0, 1, &buf);
52 if (!pvfc)
53 return htons(0);
54 /* Look at IP version field */
55 switch (*pvfc >> 4) {
56 case 4:
57 return htons(ETH_P_IP);
58 case 6:
59 return htons(ETH_P_IPV6);
60 }
61 return htons(0);
62}
63
64static void gprs_writeable(struct gprs_dev *gp)
65{
66 struct net_device *dev = gp->dev;
67
68 if (pep_writeable(gp->sk))
69 netif_wake_queue(dev);
70}
71
72/*
73 * Socket callbacks
74 */
75
76static void gprs_state_change(struct sock *sk)
77{
78 struct gprs_dev *gp = sk->sk_user_data;
79
80 if (sk->sk_state == TCP_CLOSE_WAIT) {
81 struct net_device *dev = gp->dev;
82
83 netif_stop_queue(dev);
84 netif_carrier_off(dev);
85 }
86}
87
88static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb)
89{
90 struct net_device *dev = gp->dev;
91 int err = 0;
92 __be16 protocol = gprs_type_trans(skb);
93
94 if (!protocol) {
95 err = -EINVAL;
96 goto drop;
97 }
98
99 if (skb_headroom(skb) & 3) {
100 struct sk_buff *rskb, *fs;
101 int flen = 0;
102
103 /* Phonet Pipe data header may be misaligned (3 bytes),
104 * so wrap the IP packet as a single fragment of an head-less
105 * socket buffer. The network stack will pull what it needs,
106 * but at least, the whole IP payload is not memcpy'd. */
107 rskb = netdev_alloc_skb(dev, 0);
108 if (!rskb) {
109 err = -ENOBUFS;
110 goto drop;
111 }
112 skb_shinfo(rskb)->frag_list = skb;
113 rskb->len += skb->len;
114 rskb->data_len += rskb->len;
115 rskb->truesize += rskb->len;
116
117 /* Avoid nested fragments */
118 skb_walk_frags(skb, fs)
119 flen += fs->len;
120 skb->next = skb_shinfo(skb)->frag_list;
121 skb_frag_list_init(skb);
122 skb->len -= flen;
123 skb->data_len -= flen;
124 skb->truesize -= flen;
125
126 skb = rskb;
127 }
128
129 skb->protocol = protocol;
130 skb_reset_mac_header(skb);
131 skb->dev = dev;
132
133 if (likely(dev->flags & IFF_UP)) {
134 dev->stats.rx_packets++;
135 dev->stats.rx_bytes += skb->len;
136 netif_rx(skb);
137 skb = NULL;
138 } else
139 err = -ENODEV;
140
141drop:
142 if (skb) {
143 dev_kfree_skb(skb);
144 dev->stats.rx_dropped++;
145 }
146 return err;
147}
148
149static void gprs_data_ready(struct sock *sk)
150{
151 struct gprs_dev *gp = sk->sk_user_data;
152 struct sk_buff *skb;
153
154 while ((skb = pep_read(sk)) != NULL) {
155 skb_orphan(skb);
156 gprs_recv(gp, skb);
157 }
158}
159
160static void gprs_write_space(struct sock *sk)
161{
162 struct gprs_dev *gp = sk->sk_user_data;
163
164 if (netif_running(gp->dev))
165 gprs_writeable(gp);
166}
167
168/*
169 * Network device callbacks
170 */
171
172static int gprs_open(struct net_device *dev)
173{
174 struct gprs_dev *gp = netdev_priv(dev);
175
176 gprs_writeable(gp);
177 return 0;
178}
179
180static int gprs_close(struct net_device *dev)
181{
182 netif_stop_queue(dev);
183 return 0;
184}
185
186static netdev_tx_t gprs_xmit(struct sk_buff *skb, struct net_device *dev)
187{
188 struct gprs_dev *gp = netdev_priv(dev);
189 struct sock *sk = gp->sk;
190 int len, err;
191
192 switch (skb->protocol) {
193 case htons(ETH_P_IP):
194 case htons(ETH_P_IPV6):
195 break;
196 default:
197 dev_kfree_skb(skb);
198 return NETDEV_TX_OK;
199 }
200
201 skb_orphan(skb);
202 skb_set_owner_w(skb, sk);
203 len = skb->len;
204 err = pep_write(sk, skb);
205 if (err) {
206 net_dbg_ratelimited("%s: TX error (%d)\n", dev->name, err);
207 dev->stats.tx_aborted_errors++;
208 dev->stats.tx_errors++;
209 } else {
210 dev->stats.tx_packets++;
211 dev->stats.tx_bytes += len;
212 }
213
214 netif_stop_queue(dev);
215 if (pep_writeable(sk))
216 netif_wake_queue(dev);
217 return NETDEV_TX_OK;
218}
219
220static int gprs_set_mtu(struct net_device *dev, int new_mtu)
221{
222 if ((new_mtu < 576) || (new_mtu > (PHONET_MAX_MTU - 11)))
223 return -EINVAL;
224
225 dev->mtu = new_mtu;
226 return 0;
227}
228
229static const struct net_device_ops gprs_netdev_ops = {
230 .ndo_open = gprs_open,
231 .ndo_stop = gprs_close,
232 .ndo_start_xmit = gprs_xmit,
233 .ndo_change_mtu = gprs_set_mtu,
234};
235
236static void gprs_setup(struct net_device *dev)
237{
238 dev->features = NETIF_F_FRAGLIST;
239 dev->type = ARPHRD_PHONET_PIPE;
240 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
241 dev->mtu = GPRS_DEFAULT_MTU;
242 dev->hard_header_len = 0;
243 dev->addr_len = 0;
244 dev->tx_queue_len = 10;
245
246 dev->netdev_ops = &gprs_netdev_ops;
247 dev->destructor = free_netdev;
248}
249
250/*
251 * External interface
252 */
253
254/*
255 * Attach a GPRS interface to a datagram socket.
256 * Returns the interface index on success, negative error code on error.
257 */
258int gprs_attach(struct sock *sk)
259{
260 static const char ifname[] = "gprs%d";
261 struct gprs_dev *gp;
262 struct net_device *dev;
263 int err;
264
265 if (unlikely(sk->sk_type == SOCK_STREAM))
266 return -EINVAL; /* need packet boundaries */
267
268 /* Create net device */
269 dev = alloc_netdev(sizeof(*gp), ifname, NET_NAME_UNKNOWN, gprs_setup);
270 if (!dev)
271 return -ENOMEM;
272 gp = netdev_priv(dev);
273 gp->sk = sk;
274 gp->dev = dev;
275
276 netif_stop_queue(dev);
277 err = register_netdev(dev);
278 if (err) {
279 free_netdev(dev);
280 return err;
281 }
282
283 lock_sock(sk);
284 if (unlikely(sk->sk_user_data)) {
285 err = -EBUSY;
286 goto out_rel;
287 }
288 if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) ||
289 sock_flag(sk, SOCK_DEAD))) {
290 err = -EINVAL;
291 goto out_rel;
292 }
293 sk->sk_user_data = gp;
294 gp->old_state_change = sk->sk_state_change;
295 gp->old_data_ready = sk->sk_data_ready;
296 gp->old_write_space = sk->sk_write_space;
297 sk->sk_state_change = gprs_state_change;
298 sk->sk_data_ready = gprs_data_ready;
299 sk->sk_write_space = gprs_write_space;
300 release_sock(sk);
301 sock_hold(sk);
302
303 printk(KERN_DEBUG"%s: attached\n", dev->name);
304 return dev->ifindex;
305
306out_rel:
307 release_sock(sk);
308 unregister_netdev(dev);
309 return err;
310}
311
312void gprs_detach(struct sock *sk)
313{
314 struct gprs_dev *gp = sk->sk_user_data;
315 struct net_device *dev = gp->dev;
316
317 lock_sock(sk);
318 sk->sk_user_data = NULL;
319 sk->sk_state_change = gp->old_state_change;
320 sk->sk_data_ready = gp->old_data_ready;
321 sk->sk_write_space = gp->old_write_space;
322 release_sock(sk);
323
324 printk(KERN_DEBUG"%s: detached\n", dev->name);
325 unregister_netdev(dev);
326 sock_put(sk);
327}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * File: pep-gprs.c
4 *
5 * GPRS over Phonet pipe end point socket
6 *
7 * Copyright (C) 2008 Nokia Corporation.
8 *
9 * Author: Rémi Denis-Courmont
10 */
11
12#include <linux/kernel.h>
13#include <linux/netdevice.h>
14#include <linux/if_ether.h>
15#include <linux/if_arp.h>
16#include <net/sock.h>
17
18#include <linux/if_phonet.h>
19#include <net/tcp_states.h>
20#include <net/phonet/gprs.h>
21
22#define GPRS_DEFAULT_MTU 1400
23
24struct gprs_dev {
25 struct sock *sk;
26 void (*old_state_change)(struct sock *);
27 void (*old_data_ready)(struct sock *);
28 void (*old_write_space)(struct sock *);
29
30 struct net_device *dev;
31};
32
33static __be16 gprs_type_trans(struct sk_buff *skb)
34{
35 const u8 *pvfc;
36 u8 buf;
37
38 pvfc = skb_header_pointer(skb, 0, 1, &buf);
39 if (!pvfc)
40 return htons(0);
41 /* Look at IP version field */
42 switch (*pvfc >> 4) {
43 case 4:
44 return htons(ETH_P_IP);
45 case 6:
46 return htons(ETH_P_IPV6);
47 }
48 return htons(0);
49}
50
51static void gprs_writeable(struct gprs_dev *gp)
52{
53 struct net_device *dev = gp->dev;
54
55 if (pep_writeable(gp->sk))
56 netif_wake_queue(dev);
57}
58
59/*
60 * Socket callbacks
61 */
62
63static void gprs_state_change(struct sock *sk)
64{
65 struct gprs_dev *gp = sk->sk_user_data;
66
67 if (sk->sk_state == TCP_CLOSE_WAIT) {
68 struct net_device *dev = gp->dev;
69
70 netif_stop_queue(dev);
71 netif_carrier_off(dev);
72 }
73}
74
75static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb)
76{
77 struct net_device *dev = gp->dev;
78 int err = 0;
79 __be16 protocol = gprs_type_trans(skb);
80
81 if (!protocol) {
82 err = -EINVAL;
83 goto drop;
84 }
85
86 if (skb_headroom(skb) & 3) {
87 struct sk_buff *rskb, *fs;
88 int flen = 0;
89
90 /* Phonet Pipe data header may be misaligned (3 bytes),
91 * so wrap the IP packet as a single fragment of an head-less
92 * socket buffer. The network stack will pull what it needs,
93 * but at least, the whole IP payload is not memcpy'd. */
94 rskb = netdev_alloc_skb(dev, 0);
95 if (!rskb) {
96 err = -ENOBUFS;
97 goto drop;
98 }
99 skb_shinfo(rskb)->frag_list = skb;
100 rskb->len += skb->len;
101 rskb->data_len += rskb->len;
102 rskb->truesize += rskb->len;
103
104 /* Avoid nested fragments */
105 skb_walk_frags(skb, fs)
106 flen += fs->len;
107 skb->next = skb_shinfo(skb)->frag_list;
108 skb_frag_list_init(skb);
109 skb->len -= flen;
110 skb->data_len -= flen;
111 skb->truesize -= flen;
112
113 skb = rskb;
114 }
115
116 skb->protocol = protocol;
117 skb_reset_mac_header(skb);
118 skb->dev = dev;
119
120 if (likely(dev->flags & IFF_UP)) {
121 dev->stats.rx_packets++;
122 dev->stats.rx_bytes += skb->len;
123 netif_rx(skb);
124 skb = NULL;
125 } else
126 err = -ENODEV;
127
128drop:
129 if (skb) {
130 dev_kfree_skb(skb);
131 dev->stats.rx_dropped++;
132 }
133 return err;
134}
135
136static void gprs_data_ready(struct sock *sk)
137{
138 struct gprs_dev *gp = sk->sk_user_data;
139 struct sk_buff *skb;
140
141 while ((skb = pep_read(sk)) != NULL) {
142 skb_orphan(skb);
143 gprs_recv(gp, skb);
144 }
145}
146
147static void gprs_write_space(struct sock *sk)
148{
149 struct gprs_dev *gp = sk->sk_user_data;
150
151 if (netif_running(gp->dev))
152 gprs_writeable(gp);
153}
154
155/*
156 * Network device callbacks
157 */
158
159static int gprs_open(struct net_device *dev)
160{
161 struct gprs_dev *gp = netdev_priv(dev);
162
163 gprs_writeable(gp);
164 return 0;
165}
166
167static int gprs_close(struct net_device *dev)
168{
169 netif_stop_queue(dev);
170 return 0;
171}
172
173static netdev_tx_t gprs_xmit(struct sk_buff *skb, struct net_device *dev)
174{
175 struct gprs_dev *gp = netdev_priv(dev);
176 struct sock *sk = gp->sk;
177 int len, err;
178
179 switch (skb->protocol) {
180 case htons(ETH_P_IP):
181 case htons(ETH_P_IPV6):
182 break;
183 default:
184 dev_kfree_skb(skb);
185 return NETDEV_TX_OK;
186 }
187
188 skb_orphan(skb);
189 skb_set_owner_w(skb, sk);
190 len = skb->len;
191 err = pep_write(sk, skb);
192 if (err) {
193 net_dbg_ratelimited("%s: TX error (%d)\n", dev->name, err);
194 dev->stats.tx_aborted_errors++;
195 dev->stats.tx_errors++;
196 } else {
197 dev->stats.tx_packets++;
198 dev->stats.tx_bytes += len;
199 }
200
201 netif_stop_queue(dev);
202 if (pep_writeable(sk))
203 netif_wake_queue(dev);
204 return NETDEV_TX_OK;
205}
206
207static const struct net_device_ops gprs_netdev_ops = {
208 .ndo_open = gprs_open,
209 .ndo_stop = gprs_close,
210 .ndo_start_xmit = gprs_xmit,
211};
212
213static void gprs_setup(struct net_device *dev)
214{
215 dev->features = NETIF_F_FRAGLIST;
216 dev->type = ARPHRD_PHONET_PIPE;
217 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
218 dev->mtu = GPRS_DEFAULT_MTU;
219 dev->min_mtu = 576;
220 dev->max_mtu = (PHONET_MAX_MTU - 11);
221 dev->hard_header_len = 0;
222 dev->addr_len = 0;
223 dev->tx_queue_len = 10;
224
225 dev->netdev_ops = &gprs_netdev_ops;
226 dev->needs_free_netdev = true;
227}
228
229/*
230 * External interface
231 */
232
233/*
234 * Attach a GPRS interface to a datagram socket.
235 * Returns the interface index on success, negative error code on error.
236 */
237int gprs_attach(struct sock *sk)
238{
239 static const char ifname[] = "gprs%d";
240 struct gprs_dev *gp;
241 struct net_device *dev;
242 int err;
243
244 if (unlikely(sk->sk_type == SOCK_STREAM))
245 return -EINVAL; /* need packet boundaries */
246
247 /* Create net device */
248 dev = alloc_netdev(sizeof(*gp), ifname, NET_NAME_UNKNOWN, gprs_setup);
249 if (!dev)
250 return -ENOMEM;
251 gp = netdev_priv(dev);
252 gp->sk = sk;
253 gp->dev = dev;
254
255 netif_stop_queue(dev);
256 err = register_netdev(dev);
257 if (err) {
258 free_netdev(dev);
259 return err;
260 }
261
262 lock_sock(sk);
263 if (unlikely(sk->sk_user_data)) {
264 err = -EBUSY;
265 goto out_rel;
266 }
267 if (unlikely((1 << sk->sk_state & (TCPF_CLOSE|TCPF_LISTEN)) ||
268 sock_flag(sk, SOCK_DEAD))) {
269 err = -EINVAL;
270 goto out_rel;
271 }
272 sk->sk_user_data = gp;
273 gp->old_state_change = sk->sk_state_change;
274 gp->old_data_ready = sk->sk_data_ready;
275 gp->old_write_space = sk->sk_write_space;
276 sk->sk_state_change = gprs_state_change;
277 sk->sk_data_ready = gprs_data_ready;
278 sk->sk_write_space = gprs_write_space;
279 release_sock(sk);
280 sock_hold(sk);
281
282 printk(KERN_DEBUG"%s: attached\n", dev->name);
283 return dev->ifindex;
284
285out_rel:
286 release_sock(sk);
287 unregister_netdev(dev);
288 return err;
289}
290
291void gprs_detach(struct sock *sk)
292{
293 struct gprs_dev *gp = sk->sk_user_data;
294 struct net_device *dev = gp->dev;
295
296 lock_sock(sk);
297 sk->sk_user_data = NULL;
298 sk->sk_state_change = gp->old_state_change;
299 sk->sk_data_ready = gp->old_data_ready;
300 sk->sk_write_space = gp->old_write_space;
301 release_sock(sk);
302
303 printk(KERN_DEBUG"%s: detached\n", dev->name);
304 unregister_netdev(dev);
305 sock_put(sk);
306}