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         BUG_ON(!m->private);
  76         pd = m->private;
  77
  78         if (!pd->tunnel)
  79                 l2tp_dfs_next_tunnel(pd);
  80         else
  81                 l2tp_dfs_next_session(pd);
  82
  83         /* NULL tunnel and session indicates end of list */
  84         if (!pd->tunnel && !pd->session)
  85                 pd = NULL;
  86
  87 out:
  88         return pd;
  89 }
  90
  91 static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
  92 {
  93         (*pos)++;
  94         return NULL;
  95 }
  96
  97 static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
  98 {
  99         struct l2tp_dfs_seq_data *pd = v;
 100
 101         if (!pd || pd == SEQ_START_TOKEN)
 102                 return;
 103
 104         /* Drop reference taken by last invocation of l2tp_dfs_next_session()
 105          * or l2tp_dfs_next_tunnel().
 106          */
 107         if (pd->session) {
 108                 l2tp_session_dec_refcount(pd->session);
 109                 pd->session = NULL;
 110         }
 111         if (pd->tunnel) {
 112                 l2tp_tunnel_dec_refcount(pd->tunnel);
 113                 pd->tunnel = NULL;
 114         }
 115 }
 116
 117 static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
 118 {
 119         struct l2tp_tunnel *tunnel = v;
 120         int session_count = 0;
 121         int hash;
 122         struct hlist_node *walk;
 123         struct hlist_node *tmp;
 124
 125         read_lock_bh(&tunnel->hlist_lock);
 126         for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
 127                 hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
 128                         struct l2tp_session *session;
 129
 130                         session = hlist_entry(walk, struct l2tp_session, hlist);
 131                         if (session->session_id == 0)
 132                                 continue;
 133
 134                         session_count++;
 135                 }
 136         }
 137         read_unlock_bh(&tunnel->hlist_lock);
 138
 139         seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
 140         if (tunnel->sock) {
 141                 struct inet_sock *inet = inet_sk(tunnel->sock);
 142
 143 #if IS_ENABLED(CONFIG_IPV6)
 144                 if (tunnel->sock->sk_family == AF_INET6) {
 145                         const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
 146
 147                         seq_printf(m, " from %pI6c to %pI6c\n",
 148                                    &np->saddr, &tunnel->sock->sk_v6_daddr);
 149                 }
 150 #endif
 151                 if (tunnel->sock->sk_family == AF_INET)
 152                         seq_printf(m, " from %pI4 to %pI4\n",
 153                                    &inet->inet_saddr, &inet->inet_daddr);
 154
 155                 if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
 156                         seq_printf(m, " source port %hu, dest port %hu\n",
 157                                    ntohs(inet->inet_sport), ntohs(inet->inet_dport));
 158         }
 159         seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
 160                    tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
 161                    tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
 162                    "");
 163         seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
 164                    tunnel->sock ? refcount_read(&tunnel->sock->sk_refcnt) : 0,
 165                    refcount_read(&tunnel->ref_count));
 166         seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 167                    tunnel->debug,
 168                    atomic_long_read(&tunnel->stats.tx_packets),
 169                    atomic_long_read(&tunnel->stats.tx_bytes),
 170                    atomic_long_read(&tunnel->stats.tx_errors),
 171                    atomic_long_read(&tunnel->stats.rx_packets),
 172                    atomic_long_read(&tunnel->stats.rx_bytes),
 173                    atomic_long_read(&tunnel->stats.rx_errors));
 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 0/0/%c/%c/-/%s %08x %u\n",
 189                    session->recv_seq ? 'R' : '-',
 190                    session->send_seq ? 'S' : '-',
 191                    session->lns_mode ? "LNS" : "LAC",
 192                    session->debug,
 193                    jiffies_to_msecs(session->reorder_timeout));
 194         seq_printf(m, "   offset 0 l2specific %hu/%hu\n",
 195                    session->l2specific_type, l2tp_get_l2specific_len(session));
 196         if (session->cookie_len) {
 197                 seq_printf(m, "   cookie %02x%02x%02x%02x",
 198                            session->cookie[0], session->cookie[1],
 199                            session->cookie[2], session->cookie[3]);
 200                 if (session->cookie_len == 8)
 201                         seq_printf(m, "%02x%02x%02x%02x",
 202                                    session->cookie[4], session->cookie[5],
 203                                    session->cookie[6], session->cookie[7]);
 204                 seq_puts(m, "\n");
 205         }
 206         if (session->peer_cookie_len) {
 207                 seq_printf(m, "   peer cookie %02x%02x%02x%02x",
 208                            session->peer_cookie[0], session->peer_cookie[1],
 209                            session->peer_cookie[2], session->peer_cookie[3]);
 210                 if (session->peer_cookie_len == 8)
 211                         seq_printf(m, "%02x%02x%02x%02x",
 212                                    session->peer_cookie[4], session->peer_cookie[5],
 213                                    session->peer_cookie[6], session->peer_cookie[7]);
 214                 seq_puts(m, "\n");
 215         }
 216
 217         seq_printf(m, "   %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
 218                    session->nr, session->ns,
 219                    atomic_long_read(&session->stats.tx_packets),
 220                    atomic_long_read(&session->stats.tx_bytes),
 221                    atomic_long_read(&session->stats.tx_errors),
 222                    atomic_long_read(&session->stats.rx_packets),
 223                    atomic_long_read(&session->stats.rx_bytes),
 224                    atomic_long_read(&session->stats.rx_errors));
 225
 226         if (session->show)
 227                 session->show(m, session);
 228 }
 229
 230 static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
 231 {
 232         struct l2tp_dfs_seq_data *pd = v;
 233
 234         /* display header on line 1 */
 235         if (v == SEQ_START_TOKEN) {
 236                 seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
 237                 seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
 238                 seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
 239                 seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 240                 seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");
 241                 seq_puts(m, "   refcnt cnt\n");
 242                 seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");
 243                 seq_puts(m, "   [ cookie ]\n");
 244                 seq_puts(m, "   [ peer cookie ]\n");
 245                 seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
 246                 seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
 247                 goto out;
 248         }
 249
 250         if (!pd->session)
 251                 l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
 252         else
 253                 l2tp_dfs_seq_session_show(m, pd->session);
 254
 255 out:
 256         return 0;
 257 }
 258
 259 static const struct seq_operations l2tp_dfs_seq_ops = {
 260         .start          = l2tp_dfs_seq_start,
 261         .next           = l2tp_dfs_seq_next,
 262         .stop           = l2tp_dfs_seq_stop,
 263         .show           = l2tp_dfs_seq_show,
 264 };
 265
 266 static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
 267 {
 268         struct l2tp_dfs_seq_data *pd;
 269         struct seq_file *seq;
 270         int rc = -ENOMEM;
 271
 272         pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 273         if (!pd)
 274                 goto out;
 275
 276         /* Derive the network namespace from the pid opening the
 277          * file.
 278          */
 279         pd->net = get_net_ns_by_pid(current->pid);
 280         if (IS_ERR(pd->net)) {
 281                 rc = PTR_ERR(pd->net);
 282                 goto err_free_pd;
 283         }
 284
 285         rc = seq_open(file, &l2tp_dfs_seq_ops);
 286         if (rc)
 287                 goto err_free_net;
 288
 289         seq = file->private_data;
 290         seq->private = pd;
 291
 292 out:
 293         return rc;
 294
 295 err_free_net:
 296         put_net(pd->net);
 297 err_free_pd:
 298         kfree(pd);
 299         goto out;
 300 }
 301
 302 static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
 303 {
 304         struct l2tp_dfs_seq_data *pd;
 305         struct seq_file *seq;
 306
 307         seq = file->private_data;
 308         pd = seq->private;
 309         if (pd->net)
 310                 put_net(pd->net);
 311         kfree(pd);
 312         seq_release(inode, file);
 313
 314         return 0;
 315 }
 316
 317 static const struct file_operations l2tp_dfs_fops = {
 318         .owner          = THIS_MODULE,
 319         .open           = l2tp_dfs_seq_open,
 320         .read           = seq_read,
 321         .llseek         = seq_lseek,
 322         .release        = l2tp_dfs_seq_release,
 323 };
 324
 325 static int __init l2tp_debugfs_init(void)
 326 {
 327         rootdir = debugfs_create_dir("l2tp", NULL);
 328
 329         debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
 330
 331         pr_info("L2TP debugfs support\n");
 332
 333         return 0;
 334 }
 335
 336 static void __exit l2tp_debugfs_exit(void)
 337 {
 338         debugfs_remove_recursive(rootdir);
 339 }
 340
 341 module_init(l2tp_debugfs_init);
 342 module_exit(l2tp_debugfs_exit);
 343
 344 MODULE_LICENSE("GPL");
 345 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 346 MODULE_DESCRIPTION("L2TP debugfs driver");
 347 MODULE_VERSION("1.0");