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 <net/ax25.h> 20 #include <linux/inet.h> 21 #include <linux/netdevice.h> 22 #include <linux/if_arp.h> 23 #include <linux/skbuff.h> 24 #include <net/sock.h> 25 #include <asm/uaccess.h> 26 #include <asm/system.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/netfilter.h> 35 #include <linux/sysctl.h> 36 #include <net/ip.h> 37 #include <net/arp.h> 38 39 /* 40 * IP over AX.25 encapsulation. 41 */ 42 43 /* 44 * Shove an AX.25 UI header on an IP packet and handle ARP 45 */ 46 47 #ifdef CONFIG_INET 48 49 int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) 50 { 51 unsigned char *buff; 52 53 /* they sometimes come back to us... */ 54 if (type == ETH_P_AX25) 55 return 0; 56 57 /* header is an AX.25 UI frame from us to them */ 58 buff = skb_push(skb, AX25_HEADER_LEN); 59 *buff++ = 0x00; /* KISS DATA */ 60 61 if (daddr != NULL) 62 memcpy(buff, daddr, dev->addr_len); /* Address specified */ 63 64 buff[6] &= ~AX25_CBIT; 65 buff[6] &= ~AX25_EBIT; 66 buff[6] |= AX25_SSSID_SPARE; 67 buff += AX25_ADDR_LEN; 68 69 if (saddr != NULL) 70 memcpy(buff, saddr, dev->addr_len); 71 else 72 memcpy(buff, dev->dev_addr, dev->addr_len); 73 74 buff[6] &= ~AX25_CBIT; 75 buff[6] |= AX25_EBIT; 76 buff[6] |= AX25_SSSID_SPARE; 77 buff += AX25_ADDR_LEN; 78 79 *buff++ = AX25_UI; /* UI */ 80 81 /* Append a suitable AX.25 PID */ 82 switch (type) { 83 case ETH_P_IP: 84 *buff++ = AX25_P_IP; 85 break; 86 case ETH_P_ARP: 87 *buff++ = AX25_P_ARP; 88 break; 89 default: 90 printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type); 91 *buff++ = 0; 92 break; 93 } 94 95 if (daddr != NULL) 96 return AX25_HEADER_LEN; 97 98 return -AX25_HEADER_LEN; /* Unfinished header */ 99 } 100 101 int ax25_rebuild_header(struct sk_buff *skb) 102 { 103 struct sk_buff *ourskb; 104 unsigned char *bp = skb->data; 105 ax25_route *route; 106 struct net_device *dev = NULL; 107 ax25_address *src, *dst; 108 ax25_digi *digipeat = NULL; 109 ax25_dev *ax25_dev; 110 ax25_cb *ax25; 111 char ip_mode = ' '; 112 113 dst = (ax25_address *)(bp + 1); 114 src = (ax25_address *)(bp + 8); 115 116 if (arp_find(bp + 1, skb)) 117 return 1; 118 119 route = ax25_get_route(dst, NULL); 120 if (route) { 121 digipeat = route->digipeat; 122 dev = route->dev; 123 ip_mode = route->ip_mode; 124 }; 125 126 if (dev == NULL) 127 dev = skb->dev; 128 129 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { 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 ourskb->nh.raw = ourskb->data; 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 if (route) 211 ax25_put_route(route); 212 213 return 1; 214 } 215 216 #else /* INET */ 217 218 int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) 219 { 220 return -AX25_HEADER_LEN; 221 } 222 223 int ax25_rebuild_header(struct sk_buff *skb) 224 { 225 return 1; 226 } 227 228 #endif 229 230 EXPORT_SYMBOL(ax25_hard_header); 231 EXPORT_SYMBOL(ax25_rebuild_header); 232