net/ax25/ax25_route.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *
0004  * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
0005  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
0006  * Copyright (C) Steven Whitehouse GW7RRM (stevew@acm.org)
0007  * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
0008  * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
0009  * Copyright (C) Frederic Rible F1OAT (frible@teaser.fr)
0010  */
0011
0012 #include <linux/capability.h>
0013 #include <linux/errno.h>
0014 #include <linux/types.h>
0015 #include <linux/socket.h>
0016 #include <linux/timer.h>
0017 #include <linux/in.h>
0018 #include <linux/kernel.h>
0019 #include <linux/sched.h>
0020 #include <linux/string.h>
0021 #include <linux/sockios.h>
0022 #include <linux/net.h>
0023 #include <linux/slab.h>
0024 #include <net/ax25.h>
0025 #include <linux/inet.h>
0026 #include <linux/netdevice.h>
0027 #include <linux/if_arp.h>
0028 #include <linux/skbuff.h>
0029 #include <linux/spinlock.h>
0030 #include <net/sock.h>
0031 #include <linux/uaccess.h>
0032 #include <linux/fcntl.h>
0033 #include <linux/mm.h>
0034 #include <linux/interrupt.h>
0035 #include <linux/init.h>
0036 #include <linux/seq_file.h>
0037 #include <linux/export.h>
0038
0039 static ax25_route *ax25_route_list;
0040 DEFINE_RWLOCK(ax25_route_lock);
0041
0042 void ax25_rt_device_down(struct net_device *dev)
0043 {
0044     ax25_route *s, *t, *ax25_rt;
0045
0046     write_lock_bh(&ax25_route_lock);
0047     ax25_rt = ax25_route_list;
0048     while (ax25_rt != NULL) {
0049         s       = ax25_rt;
0050         ax25_rt = ax25_rt->next;
0051
0052         if (s->dev == dev) {
0053             if (ax25_route_list == s) {
0054                 ax25_route_list = s->next;
0055                 kfree(s->digipeat);
0056                 kfree(s);
0057             } else {
0058                 for (t = ax25_route_list; t != NULL; t = t->next) {
0059                     if (t->next == s) {
0060                         t->next = s->next;
0061                         kfree(s->digipeat);
0062                         kfree(s);
0063                         break;
0064                     }
0065                 }
0066             }
0067         }
0068     }
0069     write_unlock_bh(&ax25_route_lock);
0070 }
0071
0072 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
0073 {
0074     ax25_route *ax25_rt;
0075     ax25_dev *ax25_dev;
0076     int i;
0077
0078     if (route->digi_count > AX25_MAX_DIGIS)
0079         return -EINVAL;
0080
0081     ax25_dev = ax25_addr_ax25dev(&route->port_addr);
0082     if (!ax25_dev)
0083         return -EINVAL;
0084
0085     write_lock_bh(&ax25_route_lock);
0086
0087     ax25_rt = ax25_route_list;
0088     while (ax25_rt != NULL) {
0089         if (ax25cmp(&ax25_rt->callsign, &route->dest_addr) == 0 &&
0090                 ax25_rt->dev == ax25_dev->dev) {
0091             kfree(ax25_rt->digipeat);
0092             ax25_rt->digipeat = NULL;
0093             if (route->digi_count != 0) {
0094                 if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
0095                     write_unlock_bh(&ax25_route_lock);
0096                     ax25_dev_put(ax25_dev);
0097                     return -ENOMEM;
0098                 }
0099                 ax25_rt->digipeat->lastrepeat = -1;
0100                 ax25_rt->digipeat->ndigi      = route->digi_count;
0101                 for (i = 0; i < route->digi_count; i++) {
0102                     ax25_rt->digipeat->repeated[i] = 0;
0103                     ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
0104                 }
0105             }
0106             write_unlock_bh(&ax25_route_lock);
0107             ax25_dev_put(ax25_dev);
0108             return 0;
0109         }
0110         ax25_rt = ax25_rt->next;
0111     }
0112
0113     if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
0114         write_unlock_bh(&ax25_route_lock);
0115         ax25_dev_put(ax25_dev);
0116         return -ENOMEM;
0117     }
0118
0119     ax25_rt->callsign     = route->dest_addr;
0120     ax25_rt->dev          = ax25_dev->dev;
0121     ax25_rt->digipeat     = NULL;
0122     ax25_rt->ip_mode      = ' ';
0123     if (route->digi_count != 0) {
0124         if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
0125             write_unlock_bh(&ax25_route_lock);
0126             kfree(ax25_rt);
0127             ax25_dev_put(ax25_dev);
0128             return -ENOMEM;
0129         }
0130         ax25_rt->digipeat->lastrepeat = -1;
0131         ax25_rt->digipeat->ndigi      = route->digi_count;
0132         for (i = 0; i < route->digi_count; i++) {
0133             ax25_rt->digipeat->repeated[i] = 0;
0134             ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
0135         }
0136     }
0137     ax25_rt->next   = ax25_route_list;
0138     ax25_route_list = ax25_rt;
0139     write_unlock_bh(&ax25_route_lock);
0140     ax25_dev_put(ax25_dev);
0141
0142     return 0;
0143 }
0144
0145 void __ax25_put_route(ax25_route *ax25_rt)
0146 {
0147     kfree(ax25_rt->digipeat);
0148     kfree(ax25_rt);
0149 }
0150
0151 static int ax25_rt_del(struct ax25_routes_struct *route)
0152 {
0153     ax25_route *s, *t, *ax25_rt;
0154     ax25_dev *ax25_dev;
0155
0156     if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
0157         return -EINVAL;
0158
0159     write_lock_bh(&ax25_route_lock);
0160
0161     ax25_rt = ax25_route_list;
0162     while (ax25_rt != NULL) {
0163         s       = ax25_rt;
0164         ax25_rt = ax25_rt->next;
0165         if (s->dev == ax25_dev->dev &&
0166             ax25cmp(&route->dest_addr, &s->callsign) == 0) {
0167             if (ax25_route_list == s) {
0168                 ax25_route_list = s->next;
0169                 __ax25_put_route(s);
0170             } else {
0171                 for (t = ax25_route_list; t != NULL; t = t->next) {
0172                     if (t->next == s) {
0173                         t->next = s->next;
0174                         __ax25_put_route(s);
0175                         break;
0176                     }
0177                 }
0178             }
0179         }
0180     }
0181     write_unlock_bh(&ax25_route_lock);
0182     ax25_dev_put(ax25_dev);
0183
0184     return 0;
0185 }
0186
0187 static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
0188 {
0189     ax25_route *ax25_rt;
0190     ax25_dev *ax25_dev;
0191     int err = 0;
0192
0193     if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
0194         return -EINVAL;
0195
0196     write_lock_bh(&ax25_route_lock);
0197
0198     ax25_rt = ax25_route_list;
0199     while (ax25_rt != NULL) {
0200         if (ax25_rt->dev == ax25_dev->dev &&
0201             ax25cmp(&rt_option->dest_addr, &ax25_rt->callsign) == 0) {
0202             switch (rt_option->cmd) {
0203             case AX25_SET_RT_IPMODE:
0204                 switch (rt_option->arg) {
0205                 case ' ':
0206                 case 'D':
0207                 case 'V':
0208                     ax25_rt->ip_mode = rt_option->arg;
0209                     break;
0210                 default:
0211                     err = -EINVAL;
0212                     goto out;
0213                 }
0214                 break;
0215             default:
0216                 err = -EINVAL;
0217                 goto out;
0218             }
0219         }
0220         ax25_rt = ax25_rt->next;
0221     }
0222
0223 out:
0224     write_unlock_bh(&ax25_route_lock);
0225     ax25_dev_put(ax25_dev);
0226     return err;
0227 }
0228
0229 int ax25_rt_ioctl(unsigned int cmd, void __user *arg)
0230 {
0231     struct ax25_route_opt_struct rt_option;
0232     struct ax25_routes_struct route;
0233
0234     switch (cmd) {
0235     case SIOCADDRT:
0236         if (copy_from_user(&route, arg, sizeof(route)))
0237             return -EFAULT;
0238         return ax25_rt_add(&route);
0239
0240     case SIOCDELRT:
0241         if (copy_from_user(&route, arg, sizeof(route)))
0242             return -EFAULT;
0243         return ax25_rt_del(&route);
0244
0245     case SIOCAX25OPTRT:
0246         if (copy_from_user(&rt_option, arg, sizeof(rt_option)))
0247             return -EFAULT;
0248         return ax25_rt_opt(&rt_option);
0249
0250     default:
0251         return -EINVAL;
0252     }
0253 }
0254
0255 #ifdef CONFIG_PROC_FS
0256
0257 static void *ax25_rt_seq_start(struct seq_file *seq, loff_t *pos)
0258     __acquires(ax25_route_lock)
0259 {
0260     struct ax25_route *ax25_rt;
0261     int i = 1;
0262
0263     read_lock(&ax25_route_lock);
0264     if (*pos == 0)
0265         return SEQ_START_TOKEN;
0266
0267     for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
0268         if (i == *pos)
0269             return ax25_rt;
0270         ++i;
0271     }
0272
0273     return NULL;
0274 }
0275
0276 static void *ax25_rt_seq_next(struct seq_file *seq, void *v, loff_t *pos)
0277 {
0278     ++*pos;
0279     return (v == SEQ_START_TOKEN) ? ax25_route_list :
0280         ((struct ax25_route *) v)->next;
0281 }
0282
0283 static void ax25_rt_seq_stop(struct seq_file *seq, void *v)
0284     __releases(ax25_route_lock)
0285 {
0286     read_unlock(&ax25_route_lock);
0287 }
0288
0289 static int ax25_rt_seq_show(struct seq_file *seq, void *v)
0290 {
0291     char buf[11];
0292
0293     if (v == SEQ_START_TOKEN)
0294         seq_puts(seq, "callsign  dev  mode digipeaters\n");
0295     else {
0296         struct ax25_route *ax25_rt = v;
0297         const char *callsign;
0298         int i;
0299
0300         if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0)
0301             callsign = "default";
0302         else
0303             callsign = ax2asc(buf, &ax25_rt->callsign);
0304
0305         seq_printf(seq, "%-9s %-4s",
0306             callsign,
0307             ax25_rt->dev ? ax25_rt->dev->name : "???");
0308
0309         switch (ax25_rt->ip_mode) {
0310         case 'V':
0311             seq_puts(seq, "   vc");
0312             break;
0313         case 'D':
0314             seq_puts(seq, "   dg");
0315             break;
0316         default:
0317             seq_puts(seq, "    *");
0318             break;
0319         }
0320
0321         if (ax25_rt->digipeat != NULL)
0322             for (i = 0; i < ax25_rt->digipeat->ndigi; i++)
0323                 seq_printf(seq, " %s",
0324                      ax2asc(buf, &ax25_rt->digipeat->calls[i]));
0325
0326         seq_puts(seq, "\n");
0327     }
0328     return 0;
0329 }
0330
0331 const struct seq_operations ax25_rt_seqops = {
0332     .start = ax25_rt_seq_start,
0333     .next = ax25_rt_seq_next,
0334     .stop = ax25_rt_seq_stop,
0335     .show = ax25_rt_seq_show,
0336 };
0337 #endif
0338
0339 /*
0340  *  Find AX.25 route
0341  *
0342  *  Only routes with a reference count of zero can be destroyed.
0343  *  Must be called with ax25_route_lock read locked.
0344  */
0345 ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)
0346 {
0347     ax25_route *ax25_spe_rt = NULL;
0348     ax25_route *ax25_def_rt = NULL;
0349     ax25_route *ax25_rt;
0350
0351     /*
0352      *  Bind to the physical interface we heard them on, or the default
0353      *  route if none is found;
0354      */
0355     for (ax25_rt = ax25_route_list; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
0356         if (dev == NULL) {
0357             if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev != NULL)
0358                 ax25_spe_rt = ax25_rt;
0359             if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev != NULL)
0360                 ax25_def_rt = ax25_rt;
0361         } else {
0362             if (ax25cmp(&ax25_rt->callsign, addr) == 0 && ax25_rt->dev == dev)
0363                 ax25_spe_rt = ax25_rt;
0364             if (ax25cmp(&ax25_rt->callsign, &null_ax25_address) == 0 && ax25_rt->dev == dev)
0365                 ax25_def_rt = ax25_rt;
0366         }
0367     }
0368
0369     ax25_rt = ax25_def_rt;
0370     if (ax25_spe_rt != NULL)
0371         ax25_rt = ax25_spe_rt;
0372
0373     return ax25_rt;
0374 }
0375
0376 /*
0377  *  Adjust path: If you specify a default route and want to connect
0378  *      a target on the digipeater path but w/o having a special route
0379  *  set before, the path has to be truncated from your target on.
0380  */
0381 static inline void ax25_adjust_path(ax25_address *addr, ax25_digi *digipeat)
0382 {
0383     int k;
0384
0385     for (k = 0; k < digipeat->ndigi; k++) {
0386         if (ax25cmp(addr, &digipeat->calls[k]) == 0)
0387             break;
0388     }
0389
0390     digipeat->ndigi = k;
0391 }
0392
0393
0394 /*
0395  *  Find which interface to use.
0396  */
0397 int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
0398 {
0399     ax25_uid_assoc *user;
0400     ax25_route *ax25_rt;
0401     int err = 0;
0402
0403     ax25_route_lock_use();
0404     ax25_rt = ax25_get_route(addr, NULL);
0405     if (!ax25_rt) {
0406         ax25_route_lock_unuse();
0407         return -EHOSTUNREACH;
0408     }
0409     if ((ax25->ax25_dev = ax25_dev_ax25dev(ax25_rt->dev)) == NULL) {
0410         err = -EHOSTUNREACH;
0411         goto put;
0412     }
0413
0414     user = ax25_findbyuid(current_euid());
0415     if (user) {
0416         ax25->source_addr = user->call;
0417         ax25_uid_put(user);
0418     } else {
0419         if (ax25_uid_policy && !capable(CAP_NET_BIND_SERVICE)) {
0420             err = -EPERM;
0421             goto put;
0422         }
0423         ax25->source_addr = *(ax25_address *)ax25->ax25_dev->dev->dev_addr;
0424     }
0425
0426     if (ax25_rt->digipeat != NULL) {
0427         ax25->digipeat = kmemdup(ax25_rt->digipeat, sizeof(ax25_digi),
0428                      GFP_ATOMIC);
0429         if (ax25->digipeat == NULL) {
0430             err = -ENOMEM;
0431             goto put;
0432         }
0433         ax25_adjust_path(addr, ax25->digipeat);
0434     }
0435
0436     if (ax25->sk != NULL) {
0437         local_bh_disable();
0438         bh_lock_sock(ax25->sk);
0439         sock_reset_flag(ax25->sk, SOCK_ZAPPED);
0440         bh_unlock_sock(ax25->sk);
0441         local_bh_enable();
0442     }
0443
0444 put:
0445     ax25_route_lock_unuse();
0446     return err;
0447 }
0448
0449 struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,
0450     ax25_address *dest, ax25_digi *digi)
0451 {
0452     unsigned char *bp;
0453     int len;
0454
0455     len = digi->ndigi * AX25_ADDR_LEN;
0456
0457     if (unlikely(skb_headroom(skb) < len)) {
0458         skb = skb_expand_head(skb, len);
0459         if (!skb) {
0460             printk(KERN_CRIT "AX.25: ax25_dg_build_path - out of memory\n");
0461             return NULL;
0462         }
0463     }
0464
0465     bp = skb_push(skb, len);
0466
0467     ax25_addr_build(bp, src, dest, digi, AX25_COMMAND, AX25_MODULUS);
0468
0469     return skb;
0470 }
0471
0472 /*
0473  *  Free all memory associated with routing structures.
0474  */
0475 void __exit ax25_rt_free(void)
0476 {
0477     ax25_route *s, *ax25_rt = ax25_route_list;
0478
0479     write_lock_bh(&ax25_route_lock);
0480     while (ax25_rt != NULL) {
0481         s       = ax25_rt;
0482         ax25_rt = ax25_rt->next;
0483
0484         kfree(s->digipeat);
0485         kfree(s);
0486     }
0487     write_unlock_bh(&ax25_route_lock);
0488 }