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/config.h> 10 #include <linux/errno.h> 11 #include <linux/types.h> 12 #include <linux/socket.h> 13 #include <linux/in.h> 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/sched.h> 17 #include <linux/timer.h> 18 #include <linux/string.h> 19 #include <linux/sockios.h> 20 #include <linux/net.h> 21 #include <net/ax25.h> 22 #include <linux/inet.h> 23 #include <linux/netdevice.h> 24 #include <linux/if_arp.h> 25 #include <linux/skbuff.h> 26 #include <net/sock.h> 27 #include <asm/uaccess.h> 28 #include <asm/system.h> 29 #include <linux/fcntl.h> 30 #include <linux/termios.h> /* For TIOCINQ/OUTQ */ 31 #include <linux/mm.h> 32 #include <linux/interrupt.h> 33 #include <linux/notifier.h> 34 #include <linux/proc_fs.h> 35 #include <linux/stat.h> 36 #include <linux/netfilter.h> 37 #include <linux/sysctl.h> 38 #include <net/ip.h> 39 #include <net/arp.h> 40 41 /* 42 * IP over AX.25 encapsulation. 43 */ 44 45 /* 46 * Shove an AX.25 UI header on an IP packet and handle ARP 47 */ 48 49 #ifdef CONFIG_INET 50 51 int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) 52 { 53 unsigned char *buff; 54 55 /* they sometimes come back to us... */ 56 if (type == ETH_P_AX25) 57 return 0; 58 59 /* header is an AX.25 UI frame from us to them */ 60 buff = skb_push(skb, AX25_HEADER_LEN); 61 *buff++ = 0x00; /* KISS DATA */ 62 63 if (daddr != NULL) 64 memcpy(buff, daddr, dev->addr_len); /* Address specified */ 65 66 buff[6] &= ~AX25_CBIT; 67 buff[6] &= ~AX25_EBIT; 68 buff[6] |= AX25_SSSID_SPARE; 69 buff += AX25_ADDR_LEN; 70 71 if (saddr != NULL) 72 memcpy(buff, saddr, dev->addr_len); 73 else 74 memcpy(buff, dev->dev_addr, dev->addr_len); 75 76 buff[6] &= ~AX25_CBIT; 77 buff[6] |= AX25_EBIT; 78 buff[6] |= AX25_SSSID_SPARE; 79 buff += AX25_ADDR_LEN; 80 81 *buff++ = AX25_UI; /* UI */ 82 83 /* Append a suitable AX.25 PID */ 84 switch (type) { 85 case ETH_P_IP: 86 *buff++ = AX25_P_IP; 87 break; 88 case ETH_P_ARP: 89 *buff++ = AX25_P_ARP; 90 break; 91 default: 92 printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type); 93 *buff++ = 0; 94 break; 95 } 96 97 if (daddr != NULL) 98 return AX25_HEADER_LEN; 99 100 return -AX25_HEADER_LEN; /* Unfinished header */ 101 } 102 103 int ax25_rebuild_header(struct sk_buff *skb) 104 { 105 struct sk_buff *ourskb; 106 unsigned char *bp = skb->data; 107 struct net_device *dev; 108 ax25_address *src, *dst; 109 ax25_dev *ax25_dev; 110 ax25_route _route, *route = &_route; 111 ax25_cb *ax25; 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_rt_find_route(route, dst, NULL); 120 dev = route->dev; 121 122 if (dev == NULL) 123 dev = skb->dev; 124 125 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) { 126 goto put; 127 } 128 129 if (bp[16] == AX25_P_IP) { 130 if (route->ip_mode == 'V' || (route->ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) { 131 /* 132 * We copy the buffer and release the original thereby 133 * keeping it straight 134 * 135 * Note: we report 1 back so the caller will 136 * not feed the frame direct to the physical device 137 * We don't want that to happen. (It won't be upset 138 * as we have pulled the frame from the queue by 139 * freeing it). 140 * 141 * NB: TCP modifies buffers that are still 142 * on a device queue, thus we use skb_copy() 143 * instead of using skb_clone() unless this 144 * gets fixed. 145 */ 146 147 ax25_address src_c; 148 ax25_address dst_c; 149 150 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) { 151 kfree_skb(skb); 152 goto put; 153 } 154 155 if (skb->sk != NULL) 156 skb_set_owner_w(ourskb, skb->sk); 157 158 kfree_skb(skb); 159 /* dl9sau: bugfix 160 * after kfree_skb(), dst and src which were pointer 161 * to bp which is part of skb->data would not be valid 162 * anymore hope that after skb_pull(ourskb, ..) our 163 * dsc_c and src_c will not become invalid 164 */ 165 bp = ourskb->data; 166 dst_c = *(ax25_address *)(bp + 1); 167 src_c = *(ax25_address *)(bp + 8); 168 169 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */ 170 ourskb->nh.raw = ourskb->data; 171 172 ax25=ax25_send_frame( 173 ourskb, 174 ax25_dev->values[AX25_VALUES_PACLEN], 175 &src_c, 176 &dst_c, route->digipeat, dev); 177 if (ax25) { 178 ax25_cb_put(ax25); 179 } 180 goto put; 181 } 182 } 183 184 bp[7] &= ~AX25_CBIT; 185 bp[7] &= ~AX25_EBIT; 186 bp[7] |= AX25_SSSID_SPARE; 187 188 bp[14] &= ~AX25_CBIT; 189 bp[14] |= AX25_EBIT; 190 bp[14] |= AX25_SSSID_SPARE; 191 192 skb_pull(skb, AX25_KISS_HEADER_LEN); 193 194 if (route->digipeat != NULL) { 195 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) { 196 kfree_skb(skb); 197 goto put; 198 } 199 200 skb = ourskb; 201 } 202 203 ax25_queue_xmit(skb, dev); 204 205 put: 206 ax25_put_route(route); 207 208 return 1; 209 } 210 211 #else /* INET */ 212 213 int ax25_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len) 214 { 215 return -AX25_HEADER_LEN; 216 } 217 218 int ax25_rebuild_header(struct sk_buff *skb) 219 { 220 return 1; 221 } 222 223 #endif 224 225 EXPORT_SYMBOL(ax25_hard_header); 226 EXPORT_SYMBOL(ax25_rebuild_header); 227