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         /* Drop reference taken during previous invocation */
  61         if (pd->session)
  62                 l2tp_session_dec_refcount(pd->session);
  63
  64         pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
  65         pd->session_idx++;
  66
  67         if (pd->session == NULL) {
  68                 pd->session_idx = 0;
  69                 l2tp_dfs_next_tunnel(pd);
  70         }
  71
  72 }
  73
  74 static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
  75 {
  76         struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
  77         loff_t pos = *offs;
  78
  79         if (!pos)
  80                 goto out;
  81
  82         BUG_ON(m->private == NULL);
  83         pd = m->private;
  84
  85         if (pd->tunnel == NULL)
  86                 l2tp_dfs_next_tunnel(pd);
  87         else
  88                 l2tp_dfs_next_session(pd);
  89
  90         /* NULL tunnel and session indicates end of list */
  91         if ((pd->tunnel == NULL) && (pd->session == NULL))
  92                 pd = NULL;
  93
  94 out:
  95         return pd;
  96 }
  97
  98
  99 static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
 100 {
 101         (*pos)++;
 102         return NULL;
 103 }
 104
 105 static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
 106 {
 107         struct l2tp_dfs_seq_data *pd = v;
 108
 109         if (!pd || pd == SEQ_START_TOKEN)
 110                 return;
 111
 112         /* Drop reference taken by last invocation of l2tp_dfs_next_session()
 113          * or l2tp_dfs_next_tunnel().
 114          */
 115         if (pd->session) {
 116                 l2tp_session_dec_refcount(pd->session);
 117                 pd->session = NULL;
 118         }
 119         if (pd->tunnel) {
 120                 l2tp_tunnel_dec_refcount(pd->tunnel);
 121                 pd->tunnel = NULL;
 122         }
 123 }
 124
 125 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
 126 {
 127         struct l2tp_tunnel *tunnel = v;
 128         int session_count = 0;
 129         int hash;
 130         struct hlist_node *walk;
 131         struct hlist_node *tmp;
 132
 133         read_lock_bh(&tunnel->hlist_lock);
 134         for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
 135                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
 136                         struct l2tp_session *session;
 137
 138                         session = hlist_entry(walk, struct l2tp_session, hlist);
 139                         if (session->session_id == 0)
 140                                 continue;
 141
 142                         session_count++;
 143                 }
 144         }
 145         read_unlock_bh(&tunnel->hlist_lock);
 146
 147         seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
 148         if (tunnel->sock) {
 149                 struct inet_sock *inet = inet_sk(tunnel->sock);
 150
 151 #if IS_ENABLED(CONFIG_IPV6)
 152                 if (tunnel->sock->sk_family == AF_INET6) {
 153                         const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
 154
 155                         seq_printf(m, " from %pI6c to %pI6c\n",
 156                                 &np->saddr, &tunnel->sock->sk_v6_daddr);
 157                 } else
 158 #endif
 159                 seq_printf(m, " from %pI4 to %pI4\n",
 160                            &inet->inet_saddr, &inet->inet_daddr);
 161                 if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
 162                         seq_printf(m, " source port %hu, dest port %hu\n",
 163                                    ntohs(inet->inet_sport), ntohs(inet->inet_dport));
 164         }
 165         seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
 166                    tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
 167                    tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
 168                    "");
 169         seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
 170                    tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
 171                    refcount_read(&tunnel->ref_count));
 172         seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 173                    tunnel->debug,
 174                    atomic_long_read(&tunnel->stats.tx_packets),
 175                    atomic_long_read(&tunnel->stats.tx_bytes),
 176                    atomic_long_read(&tunnel->stats.tx_errors),
 177                    atomic_long_read(&tunnel->stats.rx_packets),
 178                    atomic_long_read(&tunnel->stats.rx_bytes),
 179                    atomic_long_read(&tunnel->stats.rx_errors));
 180 }
 181
 182 static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
 183 {
 184         struct l2tp_session *session = v;
 185
 186         seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,
 187                    session->peer_session_id,
 188                    session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
 189                    session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
 190                    "");
 191         if (session->send_seq || session->recv_seq)
 192                 seq_printf(m, "   nr %hu, ns %hu\n", session->nr, session->ns);
 193         seq_printf(m, "   refcnt %d\n", refcount_read(&session->ref_count));
 194         seq_printf(m, "   config 0/0/%c/%c/-/%s %08x %u\n",
 195                    session->recv_seq ? 'R' : '-',
 196                    session->send_seq ? 'S' : '-',
 197                    session->lns_mode ? "LNS" : "LAC",
 198                    session->debug,
 199                    jiffies_to_msecs(session->reorder_timeout));
 200         seq_printf(m, "   offset 0 l2specific %hu/%hu\n",
 201                    session->l2specific_type, l2tp_get_l2specific_len(session));
 202         if (session->cookie_len) {
 203                 seq_printf(m, "   cookie %02x%02x%02x%02x",
 204                            session->cookie[0], session->cookie[1],
 205                            session->cookie[2], session->cookie[3]);
 206                 if (session->cookie_len == 8)
 207                         seq_printf(m, "%02x%02x%02x%02x",
 208                                    session->cookie[4], session->cookie[5],
 209                                    session->cookie[6], session->cookie[7]);
 210                 seq_printf(m, "\n");
 211         }
 212         if (session->peer_cookie_len) {
 213                 seq_printf(m, "   peer cookie %02x%02x%02x%02x",
 214                            session->peer_cookie[0], session->peer_cookie[1],
 215                            session->peer_cookie[2], session->peer_cookie[3]);
 216                 if (session->peer_cookie_len == 8)
 217                         seq_printf(m, "%02x%02x%02x%02x",
 218                                    session->peer_cookie[4], session->peer_cookie[5],
 219                                    session->peer_cookie[6], session->peer_cookie[7]);
 220                 seq_printf(m, "\n");
 221         }
 222
 223         seq_printf(m, "   %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 224                    session->nr, session->ns,
 225                    atomic_long_read(&session->stats.tx_packets),
 226                    atomic_long_read(&session->stats.tx_bytes),
 227                    atomic_long_read(&session->stats.tx_errors),
 228                    atomic_long_read(&session->stats.rx_packets),
 229                    atomic_long_read(&session->stats.rx_bytes),
 230                    atomic_long_read(&session->stats.rx_errors));
 231
 232         if (session->show != NULL)
 233                 session->show(m, session);
 234 }
 235
 236 static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
 237 {
 238         struct l2tp_dfs_seq_data *pd = v;
 239
 240         /* display header on line 1 */
 241         if (v == SEQ_START_TOKEN) {
 242                 seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
 243                 seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
 244                 seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
 245                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 246                 seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");
 247                 seq_puts(m, "   refcnt cnt\n");
 248                 seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");
 249                 seq_puts(m, "   [ cookie ]\n");
 250                 seq_puts(m, "   [ peer cookie ]\n");
 251                 seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
 252                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 253                 goto out;
 254         }
 255
 256         if (!pd->session)
 257                 l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
 258         else
 259                 l2tp_dfs_seq_session_show(m, pd->session);
 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");