net/l2tp/l2tp_debugfs.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* L2TP subsystem debugfs
   3  *
   4  * Copyright (c) 2010 Katalix Systems Ltd
   5  */
   6
   7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8
   9 #include <linux/module.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/socket.h>
  12 #include <linux/hash.h>
  13 #include <linux/l2tp.h>
  14 #include <linux/in.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/debugfs.h>
  18 #include <net/sock.h>
  19 #include <net/ip.h>
  20 #include <net/icmp.h>
  21 #include <net/udp.h>
  22 #include <net/inet_common.h>
  23 #include <net/inet_hashtables.h>
  24 #include <net/tcp_states.h>
  25 #include <net/protocol.h>
  26 #include <net/xfrm.h>
  27 #include <net/net_namespace.h>
  28 #include <net/netns/generic.h>
  29
  30 #include "l2tp_core.h"
  31
  32 static struct dentry *rootdir;
  33
  34 struct l2tp_dfs_seq_data {
  35         struct net      *net;
  36         netns_tracker   ns_tracker;
  37         int tunnel_idx;                 /* current tunnel */
  38         int session_idx;                /* index of session within current tunnel */
  39         struct l2tp_tunnel *tunnel;
  40         struct l2tp_session *session;   /* NULL means get next tunnel */
  41 };
  42
  43 static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
  44 {
  45         /* Drop reference taken during previous invocation */
  46         if (pd->tunnel)
  47                 l2tp_tunnel_dec_refcount(pd->tunnel);
  48
  49         pd->tunnel = l2tp_tunnel_get_nth(pd->net, pd->tunnel_idx);
  50         pd->tunnel_idx++;
  51 }
  52
  53 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
  54 {
  55         /* Drop reference taken during previous invocation */
  56         if (pd->session)
  57                 l2tp_session_dec_refcount(pd->session);
  58
  59         pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
  60         pd->session_idx++;
  61
  62         if (!pd->session) {
  63                 pd->session_idx = 0;
  64                 l2tp_dfs_next_tunnel(pd);
  65         }
  66 }
  67
  68 static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
  69 {
  70         struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
  71         loff_t pos = *offs;
  72
  73         if (!pos)
  74                 goto out;
  75
  76         if (WARN_ON(!m->private)) {
  77                 pd = NULL;
  78                 goto out;
  79         }
  80         pd = m->private;
  81
  82         if (!pd->tunnel)
  83                 l2tp_dfs_next_tunnel(pd);
  84         else
  85                 l2tp_dfs_next_session(pd);
  86
  87         /* NULL tunnel and session indicates end of list */
  88         if (!pd->tunnel && !pd->session)
  89                 pd = NULL;
  90
  91 out:
  92         return pd;
  93 }
  94
  95 static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
  96 {
  97         (*pos)++;
  98         return NULL;
  99 }
 100
 101 static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
 102 {
 103         struct l2tp_dfs_seq_data *pd = v;
 104
 105         if (!pd || pd == SEQ_START_TOKEN)
 106                 return;
 107
 108         /* Drop reference taken by last invocation of l2tp_dfs_next_session()
 109          * or l2tp_dfs_next_tunnel().
 110          */
 111         if (pd->session) {
 112                 l2tp_session_dec_refcount(pd->session);
 113                 pd->session = NULL;
 114         }
 115         if (pd->tunnel) {
 116                 l2tp_tunnel_dec_refcount(pd->tunnel);
 117                 pd->tunnel = NULL;
 118         }
 119 }
 120
 121 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
 122 {
 123         struct l2tp_tunnel *tunnel = v;
 124         struct l2tp_session *session;
 125         int session_count = 0;
 126         int hash;
 127
 128         rcu_read_lock_bh();
 129         for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
 130                 hlist_for_each_entry_rcu(session, &tunnel->session_hlist[hash], hlist) {
 131                         /* Session ID of zero is a dummy/reserved value used by pppol2tp */
 132                         if (session->session_id == 0)
 133                                 continue;
 134
 135                         session_count++;
 136                 }
 137         }
 138         rcu_read_unlock_bh();
 139
 140         seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
 141         if (tunnel->sock) {
 142                 struct inet_sock *inet = inet_sk(tunnel->sock);
 143
 144 #if IS_ENABLED(CONFIG_IPV6)
 145                 if (tunnel->sock->sk_family == AF_INET6) {
 146                         const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
 147
 148                         seq_printf(m, " from %pI6c to %pI6c\n",
 149                                    &np->saddr, &tunnel->sock->sk_v6_daddr);
 150                 }
 151 #endif
 152                 if (tunnel->sock->sk_family == AF_INET)
 153                         seq_printf(m, " from %pI4 to %pI4\n",
 154                                    &inet->inet_saddr, &inet->inet_daddr);
 155
 156                 if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
 157                         seq_printf(m, " source port %hu, dest port %hu\n",
 158                                    ntohs(inet->inet_sport), ntohs(inet->inet_dport));
 159         }
 160         seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
 161                    tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
 162                    tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
 163                    "");
 164         seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
 165                    tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
 166                    refcount_read(&tunnel->ref_count));
 167         seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 168                    0,
 169                    atomic_long_read(&tunnel->stats.tx_packets),
 170                    atomic_long_read(&tunnel->stats.tx_bytes),
 171                    atomic_long_read(&tunnel->stats.tx_errors),
 172                    atomic_long_read(&tunnel->stats.rx_packets),
 173                    atomic_long_read(&tunnel->stats.rx_bytes),
 174                    atomic_long_read(&tunnel->stats.rx_errors));
 175 }
 176
 177 static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
 178 {
 179         struct l2tp_session *session = v;
 180
 181         seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,
 182                    session->peer_session_id,
 183                    session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
 184                    session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
 185                    "");
 186         if (session->send_seq || session->recv_seq)
 187                 seq_printf(m, "   nr %u, ns %u\n", session->nr, session->ns);
 188         seq_printf(m, "   refcnt %d\n", refcount_read(&session->ref_count));
 189         seq_printf(m, "   config 0/0/%c/%c/-/%s %08x %u\n",
 190                    session->recv_seq ? 'R' : '-',
 191                    session->send_seq ? 'S' : '-',
 192                    session->lns_mode ? "LNS" : "LAC",
 193                    0,
 194                    jiffies_to_msecs(session->reorder_timeout));
 195         seq_printf(m, "   offset 0 l2specific %hu/%d\n",
 196                    session->l2specific_type, l2tp_get_l2specific_len(session));
 197         if (session->cookie_len) {
 198                 seq_printf(m, "   cookie %02x%02x%02x%02x",
 199                            session->cookie[0], session->cookie[1],
 200                            session->cookie[2], session->cookie[3]);
 201                 if (session->cookie_len == 8)
 202                         seq_printf(m, "%02x%02x%02x%02x",
 203                                    session->cookie[4], session->cookie[5],
 204                                    session->cookie[6], session->cookie[7]);
 205                 seq_puts(m, "\n");
 206         }
 207         if (session->peer_cookie_len) {
 208                 seq_printf(m, "   peer cookie %02x%02x%02x%02x",
 209                            session->peer_cookie[0], session->peer_cookie[1],
 210                            session->peer_cookie[2], session->peer_cookie[3]);
 211                 if (session->peer_cookie_len == 8)
 212                         seq_printf(m, "%02x%02x%02x%02x",
 213                                    session->peer_cookie[4], session->peer_cookie[5],
 214                                    session->peer_cookie[6], session->peer_cookie[7]);
 215                 seq_puts(m, "\n");
 216         }
 217
 218         seq_printf(m, "   %u/%u tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 219                    session->nr, session->ns,
 220                    atomic_long_read(&session->stats.tx_packets),
 221                    atomic_long_read(&session->stats.tx_bytes),
 222                    atomic_long_read(&session->stats.tx_errors),
 223                    atomic_long_read(&session->stats.rx_packets),
 224                    atomic_long_read(&session->stats.rx_bytes),
 225                    atomic_long_read(&session->stats.rx_errors));
 226
 227         if (session->show)
 228                 session->show(m, session);
 229 }
 230
 231 static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
 232 {
 233         struct l2tp_dfs_seq_data *pd = v;
 234
 235         /* display header on line 1 */
 236         if (v == SEQ_START_TOKEN) {
 237                 seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
 238                 seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
 239                 seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
 240                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 241                 seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");
 242                 seq_puts(m, "   refcnt cnt\n");
 243                 seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");
 244                 seq_puts(m, "   [ cookie ]\n");
 245                 seq_puts(m, "   [ peer cookie ]\n");
 246                 seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
 247                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 248                 goto out;
 249         }
 250
 251         if (!pd->session)
 252                 l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
 253         else
 254                 l2tp_dfs_seq_session_show(m, pd->session);
 255
 256 out:
 257         return 0;
 258 }
 259
 260 static const struct seq_operations l2tp_dfs_seq_ops = {
 261         .start          = l2tp_dfs_seq_start,
 262         .next           = l2tp_dfs_seq_next,
 263         .stop           = l2tp_dfs_seq_stop,
 264         .show           = l2tp_dfs_seq_show,
 265 };
 266
 267 static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
 268 {
 269         struct l2tp_dfs_seq_data *pd;
 270         struct seq_file *seq;
 271         int rc = -ENOMEM;
 272
 273         pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 274         if (!pd)
 275                 goto out;
 276
 277         /* Derive the network namespace from the pid opening the
 278          * file.
 279          */
 280         pd->net = get_net_ns_by_pid(current->pid);
 281         if (IS_ERR(pd->net)) {
 282                 rc = PTR_ERR(pd->net);
 283                 goto err_free_pd;
 284         }
 285         netns_tracker_alloc(pd->net, &pd->ns_tracker, GFP_KERNEL);
 286         rc = seq_open(file, &l2tp_dfs_seq_ops);
 287         if (rc)
 288                 goto err_free_net;
 289
 290         seq = file->private_data;
 291         seq->private = pd;
 292
 293 out:
 294         return rc;
 295
 296 err_free_net:
 297         put_net_track(pd->net, &pd->ns_tracker);
 298 err_free_pd:
 299         kfree(pd);
 300         goto out;
 301 }
 302
 303 static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
 304 {
 305         struct l2tp_dfs_seq_data *pd;
 306         struct seq_file *seq;
 307
 308         seq = file->private_data;
 309         pd = seq->private;
 310         if (pd->net)
 311                 put_net_track(pd->net, &pd->ns_tracker);
 312         kfree(pd);
 313         seq_release(inode, file);
 314
 315         return 0;
 316 }
 317
 318 static const struct file_operations l2tp_dfs_fops = {
 319         .owner          = THIS_MODULE,
 320         .open           = l2tp_dfs_seq_open,
 321         .read           = seq_read,
 322         .llseek         = seq_lseek,
 323         .release        = l2tp_dfs_seq_release,
 324 };
 325
 326 static int __init l2tp_debugfs_init(void)
 327 {
 328         rootdir = debugfs_create_dir("l2tp", NULL);
 329
 330         debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
 331
 332         pr_info("L2TP debugfs support\n");
 333
 334         return 0;
 335 }
 336
 337 static void __exit l2tp_debugfs_exit(void)
 338 {
 339         debugfs_remove_recursive(rootdir);
 340 }
 341
 342 module_init(l2tp_debugfs_init);
 343 module_exit(l2tp_debugfs_exit);
 344
 345 MODULE_LICENSE("GPL");
 346 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 347 MODULE_DESCRIPTION("L2TP debugfs driver");
 348 MODULE_VERSION("1.0");