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         int tunnel_idx;                 /* current tunnel */
  37         int session_idx;                /* index of session within current tunnel */
  38         struct l2tp_tunnel *tunnel;
  39         struct l2tp_session *session;   /* NULL means get next tunnel */
  40 };
  41
  42 static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
  43 {
  44         /* Drop reference taken during previous invocation */
  45         if (pd->tunnel)
  46                 l2tp_tunnel_dec_refcount(pd->tunnel);
  47
  48         pd->tunnel = l2tp_tunnel_get_nth(pd->net, pd->tunnel_idx);
  49         pd->tunnel_idx++;
  50 }
  51
  52 static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
  53 {
  54         /* Drop reference taken during previous invocation */
  55         if (pd->session)
  56                 l2tp_session_dec_refcount(pd->session);
  57
  58         pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx);
  59         pd->session_idx++;
  60
  61         if (!pd->session) {
  62                 pd->session_idx = 0;
  63                 l2tp_dfs_next_tunnel(pd);
  64         }
  65 }
  66
  67 static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
  68 {
  69         struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
  70         loff_t pos = *offs;
  71
  72         if (!pos)
  73                 goto out;
  74
  75         if (WARN_ON(!m->private)) {
  76                 pd = NULL;
  77                 goto out;
  78         }
  79         pd = m->private;
  80
  81         if (!pd->tunnel)
  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 && !pd->session)
  88                 pd = NULL;
  89
  90 out:
  91         return pd;
  92 }
  93
  94 static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
  95 {
  96         (*pos)++;
  97         return NULL;
  98 }
  99
 100 static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
 101 {
 102         struct l2tp_dfs_seq_data *pd = v;
 103
 104         if (!pd || pd == SEQ_START_TOKEN)
 105                 return;
 106
 107         /* Drop reference taken by last invocation of l2tp_dfs_next_session()
 108          * or l2tp_dfs_next_tunnel().
 109          */
 110         if (pd->session) {
 111                 l2tp_session_dec_refcount(pd->session);
 112                 pd->session = NULL;
 113         }
 114         if (pd->tunnel) {
 115                 l2tp_tunnel_dec_refcount(pd->tunnel);
 116                 pd->tunnel = NULL;
 117         }
 118 }
 119
 120 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
 121 {
 122         struct l2tp_tunnel *tunnel = v;
 123         int session_count = 0;
 124         int hash;
 125         struct hlist_node *walk;
 126         struct hlist_node *tmp;
 127
 128         read_lock_bh(&tunnel->hlist_lock);
 129         for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
 130                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
 131                         struct l2tp_session *session;
 132
 133                         session = hlist_entry(walk, struct l2tp_session, hlist);
 134                         if (session->session_id == 0)
 135                                 continue;
 136
 137                         session_count++;
 138                 }
 139         }
 140         read_unlock_bh(&tunnel->hlist_lock);
 141
 142         seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
 143         if (tunnel->sock) {
 144                 struct inet_sock *inet = inet_sk(tunnel->sock);
 145
 146 #if IS_ENABLED(CONFIG_IPV6)
 147                 if (tunnel->sock->sk_family == AF_INET6) {
 148                         const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
 149
 150                         seq_printf(m, " from %pI6c to %pI6c\n",
 151                                    &np->saddr, &tunnel->sock->sk_v6_daddr);
 152                 }
 153 #endif
 154                 if (tunnel->sock->sk_family == AF_INET)
 155                         seq_printf(m, " from %pI4 to %pI4\n",
 156                                    &inet->inet_saddr, &inet->inet_daddr);
 157
 158                 if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
 159                         seq_printf(m, " source port %hu, dest port %hu\n",
 160                                    ntohs(inet->inet_sport), ntohs(inet->inet_dport));
 161         }
 162         seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
 163                    tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
 164                    tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
 165                    "");
 166         seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
 167                    tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
 168                    refcount_read(&tunnel->ref_count));
 169         seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 170                    0,
 171                    atomic_long_read(&tunnel->stats.tx_packets),
 172                    atomic_long_read(&tunnel->stats.tx_bytes),
 173                    atomic_long_read(&tunnel->stats.tx_errors),
 174                    atomic_long_read(&tunnel->stats.rx_packets),
 175                    atomic_long_read(&tunnel->stats.rx_bytes),
 176                    atomic_long_read(&tunnel->stats.rx_errors));
 177 }
 178
 179 static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
 180 {
 181         struct l2tp_session *session = v;
 182
 183         seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,
 184                    session->peer_session_id,
 185                    session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
 186                    session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
 187                    "");
 188         if (session->send_seq || session->recv_seq)
 189                 seq_printf(m, "   nr %hu, ns %hu\n", session->nr, session->ns);
 190         seq_printf(m, "   refcnt %d\n", refcount_read(&session->ref_count));
 191         seq_printf(m, "   config 0/0/%c/%c/-/%s %08x %u\n",
 192                    session->recv_seq ? 'R' : '-',
 193                    session->send_seq ? 'S' : '-',
 194                    session->lns_mode ? "LNS" : "LAC",
 195                    0,
 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_puts(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_puts(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)
 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         if (!pd->session)
 254                 l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
 255         else
 256                 l2tp_dfs_seq_session_show(m, pd->session);
 257
 258 out:
 259         return 0;
 260 }
 261
 262 static const struct seq_operations l2tp_dfs_seq_ops = {
 263         .start          = l2tp_dfs_seq_start,
 264         .next           = l2tp_dfs_seq_next,
 265         .stop           = l2tp_dfs_seq_stop,
 266         .show           = l2tp_dfs_seq_show,
 267 };
 268
 269 static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
 270 {
 271         struct l2tp_dfs_seq_data *pd;
 272         struct seq_file *seq;
 273         int rc = -ENOMEM;
 274
 275         pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 276         if (!pd)
 277                 goto out;
 278
 279         /* Derive the network namespace from the pid opening the
 280          * file.
 281          */
 282         pd->net = get_net_ns_by_pid(current->pid);
 283         if (IS_ERR(pd->net)) {
 284                 rc = PTR_ERR(pd->net);
 285                 goto err_free_pd;
 286         }
 287
 288         rc = seq_open(file, &l2tp_dfs_seq_ops);
 289         if (rc)
 290                 goto err_free_net;
 291
 292         seq = file->private_data;
 293         seq->private = pd;
 294
 295 out:
 296         return rc;
 297
 298 err_free_net:
 299         put_net(pd->net);
 300 err_free_pd:
 301         kfree(pd);
 302         goto out;
 303 }
 304
 305 static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
 306 {
 307         struct l2tp_dfs_seq_data *pd;
 308         struct seq_file *seq;
 309
 310         seq = file->private_data;
 311         pd = seq->private;
 312         if (pd->net)
 313                 put_net(pd->net);
 314         kfree(pd);
 315         seq_release(inode, file);
 316
 317         return 0;
 318 }
 319
 320 static const struct file_operations l2tp_dfs_fops = {
 321         .owner          = THIS_MODULE,
 322         .open           = l2tp_dfs_seq_open,
 323         .read           = seq_read,
 324         .llseek         = seq_lseek,
 325         .release        = l2tp_dfs_seq_release,
 326 };
 327
 328 static int __init l2tp_debugfs_init(void)
 329 {
 330         rootdir = debugfs_create_dir("l2tp", NULL);
 331
 332         debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
 333
 334         pr_info("L2TP debugfs support\n");
 335
 336         return 0;
 337 }
 338
 339 static void __exit l2tp_debugfs_exit(void)
 340 {
 341         debugfs_remove_recursive(rootdir);
 342 }
 343
 344 module_init(l2tp_debugfs_init);
 345 module_exit(l2tp_debugfs_exit);
 346
 347 MODULE_LICENSE("GPL");
 348 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 349 MODULE_DESCRIPTION("L2TP debugfs driver");
 350 MODULE_VERSION("1.0");