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/sched.h> 16 #include <linux/timer.h> 17 #include <linux/string.h> 18 #include <linux/sockios.h> 19 #include <linux/net.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 <asm/uaccess.h> 27 #include <asm/system.h> 28 #include <linux/fcntl.h> 29 #include <linux/termios.h> /* For TIOCINQ/OUTQ */ 30 #include <linux/mm.h> 31 #include <linux/interrupt.h> 32 #include <linux/notifier.h> 33 #include <linux/proc_fs.h> 34 #include <linux/stat.h> 35 #include <linux/netfilter.h> 36 #include <linux/sysctl.h> 37 #include <net/ip.h> 38 #include <net/arp.h> 39 40 /* 41 * IP over AX.25 encapsulation. 42 */ 43 44 /* 45 * Shove an AX.25 UI header on an IP packet and handle ARP 46 */ 47 48 #ifdef CONFIG_INET 49 50 int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned 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 int ax25_rebuild_header(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 if (arp_find(bp + 1, skb)) 118 return 1; 119 120 route = ax25_get_route(dst, NULL); 121 if (route) { 122 digipeat = route->digipeat; 123 dev = route->dev; 124 ip_mode = route->ip_mode; 125 }; 126 127 if (dev == NULL) 128 dev = skb->dev; 129 130 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { 131 goto put; 132 } 133 134 if (bp[16] == AX25_P_IP) { 135 if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) { 136 /* 137 * We copy the buffer and release the original thereby 138 * keeping it straight 139 * 140 * Note: we report 1 back so the caller will 141 * not feed the frame direct to the physical device 142 * We don't want that to happen. (It won't be upset 143 * as we have pulled the frame from the queue by 144 * freeing it). 145 * 146 * NB: TCP modifies buffers that are still 147 * on a device queue, thus we use skb_copy() 148 * instead of using skb_clone() unless this 149 * gets fixed. 150 */ 151 152 ax25_address src_c; 153 ax25_address dst_c; 154 155 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) { 156 kfree_skb(skb); 157 goto put; 158 } 159 160 if (skb->sk != NULL) 161 skb_set_owner_w(ourskb, skb->sk); 162 163 kfree_skb(skb); 164 /* dl9sau: bugfix 165 * after kfree_skb(), dst and src which were pointer 166 * to bp which is part of skb->data would not be valid 167 * anymore hope that after skb_pull(ourskb, ..) our 168 * dsc_c and src_c will not become invalid 169 */ 170 bp = ourskb->data; 171 dst_c = *(ax25_address *)(bp + 1); 172 src_c = *(ax25_address *)(bp + 8); 173 174 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */ 175 ourskb->nh.raw = ourskb->data; 176 177 ax25=ax25_send_frame( 178 ourskb, 179 ax25_dev->values[AX25_VALUES_PACLEN], 180 &src_c, 181 &dst_c, digipeat, dev); 182 if (ax25) { 183 ax25_cb_put(ax25); 184 } 185 goto put; 186 } 187 } 188 189 bp[7] &= ~AX25_CBIT; 190 bp[7] &= ~AX25_EBIT; 191 bp[7] |= AX25_SSSID_SPARE; 192 193 bp[14] &= ~AX25_CBIT; 194 bp[14] |= AX25_EBIT; 195 bp[14] |= AX25_SSSID_SPARE; 196 197 skb_pull(skb, AX25_KISS_HEADER_LEN); 198 199 if (digipeat != NULL) { 200 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) { 201 kfree_skb(skb); 202 goto put; 203 } 204 205 skb = ourskb; 206 } 207 208 ax25_queue_xmit(skb, dev); 209 210 put: 211 if (route) 212 ax25_put_route(route); 213 214 return 1; 215 } 216 217 #else /* INET */ 218 219 int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) 220 { 221 return -AX25_HEADER_LEN; 222 } 223 224 int ax25_rebuild_header(struct sk_buff *skb) 225 { 226 return 1; 227 } 228 229 #endif 230 231 EXPORT_SYMBOL(ax25_hard_header); 232 EXPORT_SYMBOL(ax25_rebuild_header); 233