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 (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(addr: 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(skb: ourskb, sk: 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(skb: ourskb, AX25_HEADER_LEN - 1); /* Keep PID */ |
171 | skb_reset_network_header(skb: 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 | goto put; |
198 | |
199 | skb = ourskb; |
200 | } |
201 | |
202 | ax25_queue_xmit(skb, dev); |
203 | |
204 | put: |
205 | |
206 | ax25_route_lock_unuse(); |
207 | return NETDEV_TX_OK; |
208 | } |
209 | |
210 | #else /* INET */ |
211 | |
212 | static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, |
213 | unsigned short type, const void *daddr, |
214 | const void *saddr, unsigned int len) |
215 | { |
216 | return -AX25_HEADER_LEN; |
217 | } |
218 | |
219 | netdev_tx_t ax25_ip_xmit(struct sk_buff *skb) |
220 | { |
221 | kfree_skb(skb); |
222 | return NETDEV_TX_OK; |
223 | } |
224 | #endif |
225 | |
226 | static bool (const char *, unsigned int len) |
227 | { |
228 | ax25_digi digi; |
229 | |
230 | if (!len) |
231 | return false; |
232 | |
233 | if (header[0]) |
234 | return true; |
235 | |
236 | return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL, |
237 | NULL); |
238 | } |
239 | |
240 | const struct header_ops = { |
241 | .create = ax25_hard_header, |
242 | .validate = ax25_validate_header, |
243 | }; |
244 | |
245 | EXPORT_SYMBOL(ax25_header_ops); |
246 | EXPORT_SYMBOL(ax25_ip_xmit); |
247 | |