net/l2tp/l2tp_debugfs.c

   1 /*
   2  * L2TP subsystem debugfs
   3  *
   4  * Copyright (c) 2010 Katalix Systems Ltd
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/socket.h>
  17 #include <linux/hash.h>
  18 #include <linux/l2tp.h>
  19 #include <linux/in.h>
  20 #include <linux/etherdevice.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/debugfs.h>
  23 #include <net/sock.h>
  24 #include <net/ip.h>
  25 #include <net/icmp.h>
  26 #include <net/udp.h>
  27 #include <net/inet_common.h>
  28 #include <net/inet_hashtables.h>
  29 #include <net/tcp_states.h>
  30 #include <net/protocol.h>
  31 #include <net/xfrm.h>
  32 #include <net/net_namespace.h>
  33 #include <net/netns/generic.h>
  34
  35 #include "l2tp_core.h"
  36
  37 static struct dentry *rootdir;
  38 static struct dentry *tunnels;
  39
  40 struct l2tp_dfs_seq_data {
  41         struct net *net;
  42         int tunnel_idx;                 /* current tunnel */
  43         int session_idx;                /* index of session within current tunnel */
  44         struct l2tp_tunnel *tunnel;
  45         struct l2tp_session *session;   /* NULL means get next tunnel */
  46 };
  47
  48 static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
  49 {
  50         /* Drop reference taken during previous invocation */
  51         if (pd->tunnel)
  52                 l2tp_tunnel_dec_refcount(pd->tunnel);
  53
  54         pd->tunnel = l2tp_tunnel_get_nth(pd->net, pd->tunnel_idx);
  55         pd->tunnel_idx++;
  56 }
  57
  58 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
  59 {
  60         pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
  61         pd->session_idx++;
  62
  63         if (pd->session == NULL) {
  64                 pd->session_idx = 0;
  65                 l2tp_dfs_next_tunnel(pd);
  66         }
  67
  68 }
  69
  70 static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
  71 {
  72         struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
  73         loff_t pos = *offs;
  74
  75         if (!pos)
  76                 goto out;
  77
  78         BUG_ON(m->private == NULL);
  79         pd = m->private;
  80
  81         if (pd->tunnel == NULL)
  82                 l2tp_dfs_next_tunnel(pd);
  83         else
  84                 l2tp_dfs_next_session(pd);
  85
  86         /* NULL tunnel and session indicates end of list */
  87         if ((pd->tunnel == NULL) && (pd->session == NULL))
  88                 pd = NULL;
  89
  90 out:
  91         return pd;
  92 }
  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_tunnel() */
 109         if (pd->tunnel) {
 110                 l2tp_tunnel_dec_refcount(pd->tunnel);
 111                 pd->tunnel = NULL;
 112                 pd->session = NULL;
 113         }
 114 }
 115
 116 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
 117 {
 118         struct l2tp_tunnel *tunnel = v;
 119         int session_count = 0;
 120         int hash;
 121         struct hlist_node *walk;
 122         struct hlist_node *tmp;
 123
 124         read_lock_bh(&tunnel->hlist_lock);
 125         for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
 126                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
 127                         struct l2tp_session *session;
 128
 129                         session = hlist_entry(walk, struct l2tp_session, hlist);
 130                         if (session->session_id == 0)
 131                                 continue;
 132
 133                         session_count++;
 134                 }
 135         }
 136         read_unlock_bh(&tunnel->hlist_lock);
 137
 138         seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
 139         if (tunnel->sock) {
 140                 struct inet_sock *inet = inet_sk(tunnel->sock);
 141
 142 #if IS_ENABLED(CONFIG_IPV6)
 143                 if (tunnel->sock->sk_family == AF_INET6) {
 144                         const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
 145
 146                         seq_printf(m, " from %pI6c to %pI6c\n",
 147                                 &np->saddr, &tunnel->sock->sk_v6_daddr);
 148                 } else
 149 #endif
 150                 seq_printf(m, " from %pI4 to %pI4\n",
 151                            &inet->inet_saddr, &inet->inet_daddr);
 152                 if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
 153                         seq_printf(m, " source port %hu, dest port %hu\n",
 154                                    ntohs(inet->inet_sport), ntohs(inet->inet_dport));
 155         }
 156         seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
 157                    tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
 158                    tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
 159                    "");
 160         seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
 161                    tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
 162                    refcount_read(&tunnel->ref_count));
 163         seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 164                    tunnel->debug,
 165                    atomic_long_read(&tunnel->stats.tx_packets),
 166                    atomic_long_read(&tunnel->stats.tx_bytes),
 167                    atomic_long_read(&tunnel->stats.tx_errors),
 168                    atomic_long_read(&tunnel->stats.rx_packets),
 169                    atomic_long_read(&tunnel->stats.rx_bytes),
 170                    atomic_long_read(&tunnel->stats.rx_errors));
 171
 172         if (tunnel->show != NULL)
 173                 tunnel->show(m, tunnel);
 174 }
 175
 176 static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
 177 {
 178         struct l2tp_session *session = v;
 179
 180         seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,
 181                    session->peer_session_id,
 182                    session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
 183                    session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
 184                    "");
 185         if (session->send_seq || session->recv_seq)
 186                 seq_printf(m, "   nr %hu, ns %hu\n", session->nr, session->ns);
 187         seq_printf(m, "   refcnt %d\n", refcount_read(&session->ref_count));
 188         seq_printf(m, "   config %d/%d/%c/%c/%s/%s %08x %u\n",
 189                    session->mtu, session->mru,
 190                    session->recv_seq ? 'R' : '-',
 191                    session->send_seq ? 'S' : '-',
 192                    session->data_seq == 1 ? "IPSEQ" :
 193                    session->data_seq == 2 ? "DATASEQ" : "-",
 194                    session->lns_mode ? "LNS" : "LAC",
 195                    session->debug,
 196                    jiffies_to_msecs(session->reorder_timeout));
 197         seq_printf(m, "   offset 0 l2specific %hu/%hu\n",
 198                    session->l2specific_type, l2tp_get_l2specific_len(session));
 199         if (session->cookie_len) {
 200                 seq_printf(m, "   cookie %02x%02x%02x%02x",
 201                            session->cookie[0], session->cookie[1],
 202                            session->cookie[2], session->cookie[3]);
 203                 if (session->cookie_len == 8)
 204                         seq_printf(m, "%02x%02x%02x%02x",
 205                                    session->cookie[4], session->cookie[5],
 206                                    session->cookie[6], session->cookie[7]);
 207                 seq_printf(m, "\n");
 208         }
 209         if (session->peer_cookie_len) {
 210                 seq_printf(m, "   peer cookie %02x%02x%02x%02x",
 211                            session->peer_cookie[0], session->peer_cookie[1],
 212                            session->peer_cookie[2], session->peer_cookie[3]);
 213                 if (session->peer_cookie_len == 8)
 214                         seq_printf(m, "%02x%02x%02x%02x",
 215                                    session->peer_cookie[4], session->peer_cookie[5],
 216                                    session->peer_cookie[6], session->peer_cookie[7]);
 217                 seq_printf(m, "\n");
 218         }
 219
 220         seq_printf(m, "   %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 221                    session->nr, session->ns,
 222                    atomic_long_read(&session->stats.tx_packets),
 223                    atomic_long_read(&session->stats.tx_bytes),
 224                    atomic_long_read(&session->stats.tx_errors),
 225                    atomic_long_read(&session->stats.rx_packets),
 226                    atomic_long_read(&session->stats.rx_bytes),
 227                    atomic_long_read(&session->stats.rx_errors));
 228
 229         if (session->show != NULL)
 230                 session->show(m, session);
 231 }
 232
 233 static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
 234 {
 235         struct l2tp_dfs_seq_data *pd = v;
 236
 237         /* display header on line 1 */
 238         if (v == SEQ_START_TOKEN) {
 239                 seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
 240                 seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
 241                 seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
 242                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 243                 seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");
 244                 seq_puts(m, "   refcnt cnt\n");
 245                 seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");
 246                 seq_puts(m, "   [ cookie ]\n");
 247                 seq_puts(m, "   [ peer cookie ]\n");
 248                 seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
 249                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 250                 goto out;
 251         }
 252
 253         /* Show the tunnel or session context */
 254         if (!pd->session) {
 255                 l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
 256         } else {
 257                 l2tp_dfs_seq_session_show(m, pd->session);
 258                 l2tp_session_dec_refcount(pd->session);
 259         }
 260
 261 out:
 262         return 0;
 263 }
 264
 265 static const struct seq_operations l2tp_dfs_seq_ops = {
 266         .start          = l2tp_dfs_seq_start,
 267         .next           = l2tp_dfs_seq_next,
 268         .stop           = l2tp_dfs_seq_stop,
 269         .show           = l2tp_dfs_seq_show,
 270 };
 271
 272 static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
 273 {
 274         struct l2tp_dfs_seq_data *pd;
 275         struct seq_file *seq;
 276         int rc = -ENOMEM;
 277
 278         pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 279         if (pd == NULL)
 280                 goto out;
 281
 282         /* Derive the network namespace from the pid opening the
 283          * file.
 284          */
 285         pd->net = get_net_ns_by_pid(current->pid);
 286         if (IS_ERR(pd->net)) {
 287                 rc = PTR_ERR(pd->net);
 288                 goto err_free_pd;
 289         }
 290
 291         rc = seq_open(file, &l2tp_dfs_seq_ops);
 292         if (rc)
 293                 goto err_free_net;
 294
 295         seq = file->private_data;
 296         seq->private = pd;
 297
 298 out:
 299         return rc;
 300
 301 err_free_net:
 302         put_net(pd->net);
 303 err_free_pd:
 304         kfree(pd);
 305         goto out;
 306 }
 307
 308 static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
 309 {
 310         struct l2tp_dfs_seq_data *pd;
 311         struct seq_file *seq;
 312
 313         seq = file->private_data;
 314         pd = seq->private;
 315         if (pd->net)
 316                 put_net(pd->net);
 317         kfree(pd);
 318         seq_release(inode, file);
 319
 320         return 0;
 321 }
 322
 323 static const struct file_operations l2tp_dfs_fops = {
 324         .owner          = THIS_MODULE,
 325         .open           = l2tp_dfs_seq_open,
 326         .read           = seq_read,
 327         .llseek         = seq_lseek,
 328         .release        = l2tp_dfs_seq_release,
 329 };
 330
 331 static int __init l2tp_debugfs_init(void)
 332 {
 333         int rc = 0;
 334
 335         rootdir = debugfs_create_dir("l2tp", NULL);
 336         if (IS_ERR(rootdir)) {
 337                 rc = PTR_ERR(rootdir);
 338                 rootdir = NULL;
 339                 goto out;
 340         }
 341
 342         tunnels = debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
 343         if (tunnels == NULL)
 344                 rc = -EIO;
 345
 346         pr_info("L2TP debugfs support\n");
 347
 348 out:
 349         if (rc)
 350                 pr_warn("unable to init\n");
 351
 352         return rc;
 353 }
 354
 355 static void __exit l2tp_debugfs_exit(void)
 356 {
 357         debugfs_remove(tunnels);
 358         debugfs_remove(rootdir);
 359 }
 360
 361 module_init(l2tp_debugfs_init);
 362 module_exit(l2tp_debugfs_exit);
 363
 364 MODULE_LICENSE("GPL");
 365 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 366 MODULE_DESCRIPTION("L2TP debugfs driver");
 367 MODULE_VERSION("1.0");