1 // SPDX-License-Identifier: GPL-2.0-or-later
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
6 #include <linux/errno.h>
7 #include <linux/types.h>
8 #include <linux/socket.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>
18 #include <linux/inet.h>
19 #include <linux/netdevice.h>
20 #include <linux/if_arp.h>
21 #include <linux/skbuff.h>
23 #include <linux/uaccess.h>
24 #include <linux/fcntl.h>
25 #include <linux/termios.h> /* For TIOCINQ/OUTQ */
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>
36 * IP over AX.25 encapsulation.
40 * Shove an AX.25 UI header on an IP packet and handle ARP
45 static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
46 unsigned short type, const void *daddr,
47 const void *saddr, unsigned int len)
51 /* they sometimes come back to us... */
52 if (type == ETH_P_AX25)
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 */
60 memcpy(buff, daddr, dev->addr_len); /* Address specified */
62 buff[6] &= ~AX25_CBIT;
63 buff[6] &= ~AX25_EBIT;
64 buff[6] |= AX25_SSSID_SPARE;
65 buff += AX25_ADDR_LEN;
68 memcpy(buff, saddr, dev->addr_len);
70 memcpy(buff, dev->dev_addr, dev->addr_len);
72 buff[6] &= ~AX25_CBIT;
74 buff[6] |= AX25_SSSID_SPARE;
75 buff += AX25_ADDR_LEN;
77 *buff++ = AX25_UI; /* UI */
79 /* Append a suitable AX.25 PID */
88 printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
94 return AX25_HEADER_LEN;
96 return -AX25_HEADER_LEN; /* Unfinished header */
99 netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
101 struct sk_buff *ourskb;
102 unsigned char *bp = skb->data;
104 struct net_device *dev = NULL;
105 ax25_address *src, *dst;
106 ax25_digi *digipeat = NULL;
111 dst = (ax25_address *)(bp + 1);
112 src = (ax25_address *)(bp + 8);
114 ax25_route_lock_use();
115 route = ax25_get_route(dst, NULL);
117 digipeat = route->digipeat;
119 ip_mode = route->ip_mode;
125 if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
130 if (bp[16] == AX25_P_IP) {
131 if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
133 * We copy the buffer and release the original thereby
134 * keeping it straight
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
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
151 if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
157 skb_set_owner_w(ourskb, skb->sk);
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
167 dst_c = *(ax25_address *)(bp + 1);
168 src_c = *(ax25_address *)(bp + 8);
170 skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */
171 skb_reset_network_header(ourskb);
173 ax25=ax25_send_frame(
175 ax25_dev->values[AX25_VALUES_PACLEN],
177 &dst_c, digipeat, dev);
187 bp[7] |= AX25_SSSID_SPARE;
189 bp[14] &= ~AX25_CBIT;
191 bp[14] |= AX25_SSSID_SPARE;
193 skb_pull(skb, AX25_KISS_HEADER_LEN);
195 if (digipeat != NULL) {
196 if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
204 ax25_queue_xmit(skb, dev);
208 ax25_route_lock_unuse();
214 static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
215 unsigned short type, const void *daddr,
216 const void *saddr, unsigned int len)
218 return -AX25_HEADER_LEN;
221 netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
228 static bool ax25_validate_header(const char *header, unsigned int len)
238 return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL,
242 const struct header_ops ax25_header_ops = {
243 .create = ax25_hard_header,
244 .validate = ax25_validate_header,
247 EXPORT_SYMBOL(ax25_header_ops);
248 EXPORT_SYMBOL(ax25_ip_xmit);