1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License as published by 4 * the Free Software Foundation; either version 2 of the License, or 5 * (at your option) any later version. 6 * 7 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) 8 */ 9 #include <linux/errno.h> 10 #include <linux/types.h> 11 #include <linux/socket.h> 12 #include <linux/in.h> 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/timer.h> 16 #include <linux/string.h> 17 #include <linux/sockios.h> 18 #include <linux/net.h> 19 #include <linux/slab.h> 20 #include <net/ax25.h> 21 #include <linux/inet.h> 22 #include <linux/netdevice.h> 23 #include <linux/if_arp.h> 24 #include <linux/skbuff.h> 25 #include <net/sock.h> 26 #include <linux/uaccess.h> 27 #include <linux/fcntl.h> 28 #include <linux/termios.h> /* For TIOCINQ/OUTQ */ 29 #include <linux/mm.h> 30 #include <linux/interrupt.h> 31 #include <linux/notifier.h> 32 #include <linux/proc_fs.h> 33 #include <linux/stat.h> 34 #include <linux/sysctl.h> 35 #include <net/ip.h> 36 #include <net/arp.h> 37 38 /* 39 * IP over AX.25 encapsulation. 40 */ 41 42 /* 43 * Shove an AX.25 UI header on an IP packet and handle ARP 44 */ 45 46 #ifdef CONFIG_INET 47 48 static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, 49 unsigned short type, const void *daddr, 50 const void *saddr, unsigned int len) 51 { 52 unsigned char *buff; 53 54 /* they sometimes come back to us... */ 55 if (type == ETH_P_AX25) 56 return 0; 57 58 /* header is an AX.25 UI frame from us to them */ 59 buff = skb_push(skb, AX25_HEADER_LEN); 60 *buff++ = 0x00; /* KISS DATA */ 61 62 if (daddr != NULL) 63 memcpy(buff, daddr, dev->addr_len); /* Address specified */ 64 65 buff[6] &= ~AX25_CBIT; 66 buff[6] &= ~AX25_EBIT; 67 buff[6] |= AX25_SSSID_SPARE; 68 buff += AX25_ADDR_LEN; 69 70 if (saddr != NULL) 71 memcpy(buff, saddr, dev->addr_len); 72 else 73 memcpy(buff, dev->dev_addr, dev->addr_len); 74 75 buff[6] &= ~AX25_CBIT; 76 buff[6] |= AX25_EBIT; 77 buff[6] |= AX25_SSSID_SPARE; 78 buff += AX25_ADDR_LEN; 79 80 *buff++ = AX25_UI; /* UI */ 81 82 /* Append a suitable AX.25 PID */ 83 switch (type) { 84 case ETH_P_IP: 85 *buff++ = AX25_P_IP; 86 break; 87 case ETH_P_ARP: 88 *buff++ = AX25_P_ARP; 89 break; 90 default: 91 printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type); 92 *buff++ = 0; 93 break; 94 } 95 96 if (daddr != NULL) 97 return AX25_HEADER_LEN; 98 99 return -AX25_HEADER_LEN; /* Unfinished header */ 100 } 101 102 netdev_tx_t ax25_ip_xmit(struct sk_buff *skb) 103 { 104 struct sk_buff *ourskb; 105 unsigned char *bp = skb->data; 106 ax25_route *route; 107 struct net_device *dev = NULL; 108 ax25_address *src, *dst; 109 ax25_digi *digipeat = NULL; 110 ax25_dev *ax25_dev; 111 ax25_cb *ax25; 112 char ip_mode = ' '; 113 114 dst = (ax25_address *)(bp + 1); 115 src = (ax25_address *)(bp + 8); 116 117 ax25_route_lock_use(); 118 route = ax25_get_route(dst, NULL); 119 if (route) { 120 digipeat = route->digipeat; 121 dev = route->dev; 122 ip_mode = route->ip_mode; 123 } 124 125 if (dev == NULL) 126 dev = skb->dev; 127 128 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { 129 kfree_skb(skb); 130 goto put; 131 } 132 133 if (bp[16] == AX25_P_IP) { 134 if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) { 135 /* 136 * We copy the buffer and release the original thereby 137 * keeping it straight 138 * 139 * Note: we report 1 back so the caller will 140 * not feed the frame direct to the physical device 141 * We don't want that to happen. (It won't be upset 142 * as we have pulled the frame from the queue by 143 * freeing it). 144 * 145 * NB: TCP modifies buffers that are still 146 * on a device queue, thus we use skb_copy() 147 * instead of using skb_clone() unless this 148 * gets fixed. 149 */ 150 151 ax25_address src_c; 152 ax25_address dst_c; 153 154 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) { 155 kfree_skb(skb); 156 goto put; 157 } 158 159 if (skb->sk != NULL) 160 skb_set_owner_w(ourskb, skb->sk); 161 162 kfree_skb(skb); 163 /* dl9sau: bugfix 164 * after kfree_skb(), dst and src which were pointer 165 * to bp which is part of skb->data would not be valid 166 * anymore hope that after skb_pull(ourskb, ..) our 167 * dsc_c and src_c will not become invalid 168 */ 169 bp = ourskb->data; 170 dst_c = *(ax25_address *)(bp + 1); 171 src_c = *(ax25_address *)(bp + 8); 172 173 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */ 174 skb_reset_network_header(ourskb); 175 176 ax25=ax25_send_frame( 177 ourskb, 178 ax25_dev->values[AX25_VALUES_PACLEN], 179 &src_c, 180 &dst_c, digipeat, dev); 181 if (ax25) { 182 ax25_cb_put(ax25); 183 } 184 goto put; 185 } 186 } 187 188 bp[7] &= ~AX25_CBIT; 189 bp[7] &= ~AX25_EBIT; 190 bp[7] |= AX25_SSSID_SPARE; 191 192 bp[14] &= ~AX25_CBIT; 193 bp[14] |= AX25_EBIT; 194 bp[14] |= AX25_SSSID_SPARE; 195 196 skb_pull(skb, AX25_KISS_HEADER_LEN); 197 198 if (digipeat != NULL) { 199 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) { 200 kfree_skb(skb); 201 goto put; 202 } 203 204 skb = ourskb; 205 } 206 207 ax25_queue_xmit(skb, dev); 208 209 put: 210 211 ax25_route_lock_unuse(); 212 return NETDEV_TX_OK; 213 } 214 215 #else /* INET */ 216 217 static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, 218 unsigned short type, const void *daddr, 219 const void *saddr, unsigned int len) 220 { 221 return -AX25_HEADER_LEN; 222 } 223 224 netdev_tx_t ax25_ip_xmit(struct sk_buff *skb) 225 { 226 kfree_skb(skb); 227 return NETDEV_TX_OK; 228 } 229 #endif 230 231 static bool ax25_validate_header(const char *header, unsigned int len) 232 { 233 ax25_digi digi; 234 235 if (!len) 236 return false; 237 238 if (header[0]) 239 return true; 240 241 return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL, 242 NULL); 243 } 244 245 const struct header_ops ax25_header_ops = { 246 .create = ax25_hard_header, 247 .validate = ax25_validate_header, 248 }; 249 250 EXPORT_SYMBOL(ax25_header_ops); 251 EXPORT_SYMBOL(ax25_ip_xmit); 252