Merge tag 'ecryptfs-5.3-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-microblaze.git] / net / ax25 / ax25_ip.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5  */
6 #include <linux/errno.h>
7 #include <linux/types.h>
8 #include <linux/socket.h>
9 #include <linux/in.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/timer.h>
13 #include <linux/string.h>
14 #include <linux/sockios.h>
15 #include <linux/net.h>
16 #include <linux/slab.h>
17 #include <net/ax25.h>
18 #include <linux/inet.h>
19 #include <linux/netdevice.h>
20 #include <linux/if_arp.h>
21 #include <linux/skbuff.h>
22 #include <net/sock.h>
23 #include <linux/uaccess.h>
24 #include <linux/fcntl.h>
25 #include <linux/termios.h>      /* For TIOCINQ/OUTQ */
26 #include <linux/mm.h>
27 #include <linux/interrupt.h>
28 #include <linux/notifier.h>
29 #include <linux/proc_fs.h>
30 #include <linux/stat.h>
31 #include <linux/sysctl.h>
32 #include <net/ip.h>
33 #include <net/arp.h>
34
35 /*
36  *      IP over AX.25 encapsulation.
37  */
38
39 /*
40  *      Shove an AX.25 UI header on an IP packet and handle ARP
41  */
42
43 #ifdef CONFIG_INET
44
45 static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
46                             unsigned short type, const void *daddr,
47                             const void *saddr, unsigned int len)
48 {
49         unsigned char *buff;
50
51         /* they sometimes come back to us... */
52         if (type == ETH_P_AX25)
53                 return 0;
54
55         /* header is an AX.25 UI frame from us to them */
56         buff = skb_push(skb, AX25_HEADER_LEN);
57         *buff++ = 0x00; /* KISS DATA */
58
59         if (daddr != NULL)
60                 memcpy(buff, daddr, dev->addr_len);     /* Address specified */
61
62         buff[6] &= ~AX25_CBIT;
63         buff[6] &= ~AX25_EBIT;
64         buff[6] |= AX25_SSSID_SPARE;
65         buff    += AX25_ADDR_LEN;
66
67         if (saddr != NULL)
68                 memcpy(buff, saddr, dev->addr_len);
69         else
70                 memcpy(buff, dev->dev_addr, dev->addr_len);
71
72         buff[6] &= ~AX25_CBIT;
73         buff[6] |= AX25_EBIT;
74         buff[6] |= AX25_SSSID_SPARE;
75         buff    += AX25_ADDR_LEN;
76
77         *buff++  = AX25_UI;     /* UI */
78
79         /* Append a suitable AX.25 PID */
80         switch (type) {
81         case ETH_P_IP:
82                 *buff++ = AX25_P_IP;
83                 break;
84         case ETH_P_ARP:
85                 *buff++ = AX25_P_ARP;
86                 break;
87         default:
88                 printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
89                 *buff++ = 0;
90                 break;
91         }
92
93         if (daddr != NULL)
94                 return AX25_HEADER_LEN;
95
96         return -AX25_HEADER_LEN;        /* Unfinished header */
97 }
98
99 netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
100 {
101         struct sk_buff *ourskb;
102         unsigned char *bp  = skb->data;
103         ax25_route *route;
104         struct net_device *dev = NULL;
105         ax25_address *src, *dst;
106         ax25_digi *digipeat = NULL;
107         ax25_dev *ax25_dev;
108         ax25_cb *ax25;
109         char ip_mode = ' ';
110
111         dst = (ax25_address *)(bp + 1);
112         src = (ax25_address *)(bp + 8);
113
114         ax25_route_lock_use();
115         route = ax25_get_route(dst, NULL);
116         if (route) {
117                 digipeat = route->digipeat;
118                 dev = route->dev;
119                 ip_mode = route->ip_mode;
120         }
121
122         if (dev == NULL)
123                 dev = skb->dev;
124
125         if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
126                 kfree_skb(skb);
127                 goto put;
128         }
129
130         if (bp[16] == AX25_P_IP) {
131                 if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
132                         /*
133                          *      We copy the buffer and release the original thereby
134                          *      keeping it straight
135                          *
136                          *      Note: we report 1 back so the caller will
137                          *      not feed the frame direct to the physical device
138                          *      We don't want that to happen. (It won't be upset
139                          *      as we have pulled the frame from the queue by
140                          *      freeing it).
141                          *
142                          *      NB: TCP modifies buffers that are still
143                          *      on a device queue, thus we use skb_copy()
144                          *      instead of using skb_clone() unless this
145                          *      gets fixed.
146                          */
147
148                         ax25_address src_c;
149                         ax25_address dst_c;
150
151                         if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
152                                 kfree_skb(skb);
153                                 goto put;
154                         }
155
156                         if (skb->sk != NULL)
157                                 skb_set_owner_w(ourskb, skb->sk);
158
159                         kfree_skb(skb);
160                         /* dl9sau: bugfix
161                          * after kfree_skb(), dst and src which were pointer
162                          * to bp which is part of skb->data would not be valid
163                          * anymore hope that after skb_pull(ourskb, ..) our
164                          * dsc_c and src_c will not become invalid
165                          */
166                         bp  = ourskb->data;
167                         dst_c = *(ax25_address *)(bp + 1);
168                         src_c = *(ax25_address *)(bp + 8);
169
170                         skb_pull(ourskb, AX25_HEADER_LEN - 1);  /* Keep PID */
171                         skb_reset_network_header(ourskb);
172
173                         ax25=ax25_send_frame(
174                             ourskb,
175                             ax25_dev->values[AX25_VALUES_PACLEN],
176                             &src_c,
177                             &dst_c, digipeat, dev);
178                         if (ax25) {
179                                 ax25_cb_put(ax25);
180                         }
181                         goto put;
182                 }
183         }
184
185         bp[7]  &= ~AX25_CBIT;
186         bp[7]  &= ~AX25_EBIT;
187         bp[7]  |= AX25_SSSID_SPARE;
188
189         bp[14] &= ~AX25_CBIT;
190         bp[14] |= AX25_EBIT;
191         bp[14] |= AX25_SSSID_SPARE;
192
193         skb_pull(skb, AX25_KISS_HEADER_LEN);
194
195         if (digipeat != NULL) {
196                 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
197                         kfree_skb(skb);
198                         goto put;
199                 }
200
201                 skb = ourskb;
202         }
203
204         ax25_queue_xmit(skb, dev);
205
206 put:
207
208         ax25_route_lock_unuse();
209         return NETDEV_TX_OK;
210 }
211
212 #else   /* INET */
213
214 static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
215                             unsigned short type, const void *daddr,
216                             const void *saddr, unsigned int len)
217 {
218         return -AX25_HEADER_LEN;
219 }
220
221 netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
222 {
223         kfree_skb(skb);
224         return NETDEV_TX_OK;
225 }
226 #endif
227
228 static bool ax25_validate_header(const char *header, unsigned int len)
229 {
230         ax25_digi digi;
231
232         if (!len)
233                 return false;
234
235         if (header[0])
236                 return true;
237
238         return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL,
239                                NULL);
240 }
241
242 const struct header_ops ax25_header_ops = {
243         .create = ax25_hard_header,
244         .validate = ax25_validate_header,
245 };
246
247 EXPORT_SYMBOL(ax25_header_ops);
248 EXPORT_SYMBOL(ax25_ip_xmit);