![Guillaume Nault](/assets/img/avatar_default.png)
Take a reference on the sessions returned by l2tp_session_find_nth() (and rename it l2tp_session_get_nth() to reflect this change), so that caller is assured that the session isn't going to disappear while processing it. For procfs and debugfs handlers, the session is held in the .start() callback and dropped in .show(). Given that pppol2tp_seq_session_show() dereferences the associated PPPoL2TP socket and that l2tp_dfs_seq_session_show() might call pppol2tp_show(), we also need to call the session's .ref() callback to prevent the socket from going away from under us. Fixes:fd558d186d
("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Fixes:0ad6614048
("l2tp: Add debugfs files for dumping l2tp debug info") Fixes:309795f4be
("l2tp: Add netlink control API for L2TP") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net>
357 lines
9.2 KiB
C
357 lines
9.2 KiB
C
/*
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* L2TP subsystem debugfs
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*
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* Copyright (c) 2010 Katalix Systems Ltd
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/socket.h>
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#include <linux/hash.h>
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#include <linux/l2tp.h>
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#include <linux/in.h>
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#include <linux/etherdevice.h>
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#include <linux/spinlock.h>
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#include <linux/debugfs.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <net/icmp.h>
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#include <net/udp.h>
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#include <net/inet_common.h>
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#include <net/inet_hashtables.h>
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#include <net/tcp_states.h>
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#include <net/protocol.h>
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#include <net/xfrm.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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#include "l2tp_core.h"
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static struct dentry *rootdir;
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static struct dentry *tunnels;
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struct l2tp_dfs_seq_data {
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struct net *net;
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int tunnel_idx; /* current tunnel */
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int session_idx; /* index of session within current tunnel */
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struct l2tp_tunnel *tunnel;
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struct l2tp_session *session; /* NULL means get next tunnel */
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};
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static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
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{
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pd->tunnel = l2tp_tunnel_find_nth(pd->net, pd->tunnel_idx);
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pd->tunnel_idx++;
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}
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static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
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{
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pd->session = l2tp_session_get_nth(pd->tunnel, pd->session_idx, true);
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pd->session_idx++;
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if (pd->session == NULL) {
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pd->session_idx = 0;
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l2tp_dfs_next_tunnel(pd);
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}
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}
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static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
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{
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struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
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loff_t pos = *offs;
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if (!pos)
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goto out;
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BUG_ON(m->private == NULL);
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pd = m->private;
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if (pd->tunnel == NULL)
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l2tp_dfs_next_tunnel(pd);
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else
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l2tp_dfs_next_session(pd);
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/* NULL tunnel and session indicates end of list */
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if ((pd->tunnel == NULL) && (pd->session == NULL))
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pd = NULL;
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out:
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return pd;
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}
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static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
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{
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(*pos)++;
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return NULL;
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}
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static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
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{
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/* nothing to do */
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}
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static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
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{
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struct l2tp_tunnel *tunnel = v;
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int session_count = 0;
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int hash;
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struct hlist_node *walk;
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struct hlist_node *tmp;
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read_lock_bh(&tunnel->hlist_lock);
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for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
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hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
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struct l2tp_session *session;
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session = hlist_entry(walk, struct l2tp_session, hlist);
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if (session->session_id == 0)
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continue;
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session_count++;
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}
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}
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read_unlock_bh(&tunnel->hlist_lock);
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seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
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if (tunnel->sock) {
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struct inet_sock *inet = inet_sk(tunnel->sock);
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#if IS_ENABLED(CONFIG_IPV6)
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if (tunnel->sock->sk_family == AF_INET6) {
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const struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
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seq_printf(m, " from %pI6c to %pI6c\n",
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&np->saddr, &tunnel->sock->sk_v6_daddr);
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} else
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#endif
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seq_printf(m, " from %pI4 to %pI4\n",
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&inet->inet_saddr, &inet->inet_daddr);
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if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
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seq_printf(m, " source port %hu, dest port %hu\n",
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ntohs(inet->inet_sport), ntohs(inet->inet_dport));
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}
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seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
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tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
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tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
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"");
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seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
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tunnel->sock ? atomic_read(&tunnel->sock->sk_refcnt) : 0,
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atomic_read(&tunnel->ref_count));
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seq_printf(m, " %08x rx %ld/%ld/%ld rx %ld/%ld/%ld\n",
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tunnel->debug,
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atomic_long_read(&tunnel->stats.tx_packets),
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atomic_long_read(&tunnel->stats.tx_bytes),
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atomic_long_read(&tunnel->stats.tx_errors),
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atomic_long_read(&tunnel->stats.rx_packets),
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atomic_long_read(&tunnel->stats.rx_bytes),
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atomic_long_read(&tunnel->stats.rx_errors));
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if (tunnel->show != NULL)
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tunnel->show(m, tunnel);
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}
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static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
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{
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struct l2tp_session *session = v;
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seq_printf(m, " SESSION %u, peer %u, %s\n", session->session_id,
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session->peer_session_id,
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session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
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session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
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"");
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if (session->send_seq || session->recv_seq)
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seq_printf(m, " nr %hu, ns %hu\n", session->nr, session->ns);
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seq_printf(m, " refcnt %d\n", atomic_read(&session->ref_count));
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seq_printf(m, " config %d/%d/%c/%c/%s/%s %08x %u\n",
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session->mtu, session->mru,
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session->recv_seq ? 'R' : '-',
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session->send_seq ? 'S' : '-',
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session->data_seq == 1 ? "IPSEQ" :
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session->data_seq == 2 ? "DATASEQ" : "-",
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session->lns_mode ? "LNS" : "LAC",
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session->debug,
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jiffies_to_msecs(session->reorder_timeout));
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seq_printf(m, " offset %hu l2specific %hu/%hu\n",
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session->offset, session->l2specific_type, session->l2specific_len);
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if (session->cookie_len) {
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seq_printf(m, " cookie %02x%02x%02x%02x",
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session->cookie[0], session->cookie[1],
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session->cookie[2], session->cookie[3]);
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if (session->cookie_len == 8)
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seq_printf(m, "%02x%02x%02x%02x",
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session->cookie[4], session->cookie[5],
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session->cookie[6], session->cookie[7]);
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seq_printf(m, "\n");
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}
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if (session->peer_cookie_len) {
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seq_printf(m, " peer cookie %02x%02x%02x%02x",
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session->peer_cookie[0], session->peer_cookie[1],
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session->peer_cookie[2], session->peer_cookie[3]);
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if (session->peer_cookie_len == 8)
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seq_printf(m, "%02x%02x%02x%02x",
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session->peer_cookie[4], session->peer_cookie[5],
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session->peer_cookie[6], session->peer_cookie[7]);
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seq_printf(m, "\n");
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}
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seq_printf(m, " %hu/%hu tx %ld/%ld/%ld rx %ld/%ld/%ld\n",
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session->nr, session->ns,
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atomic_long_read(&session->stats.tx_packets),
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atomic_long_read(&session->stats.tx_bytes),
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atomic_long_read(&session->stats.tx_errors),
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atomic_long_read(&session->stats.rx_packets),
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atomic_long_read(&session->stats.rx_bytes),
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atomic_long_read(&session->stats.rx_errors));
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if (session->show != NULL)
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session->show(m, session);
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}
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static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
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{
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struct l2tp_dfs_seq_data *pd = v;
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/* display header on line 1 */
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if (v == SEQ_START_TOKEN) {
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seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
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seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
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seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
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seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
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seq_puts(m, " SESSION ID, peer ID, PWTYPE\n");
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seq_puts(m, " refcnt cnt\n");
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seq_puts(m, " offset OFFSET l2specific TYPE/LEN\n");
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seq_puts(m, " [ cookie ]\n");
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seq_puts(m, " [ peer cookie ]\n");
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seq_puts(m, " config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
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seq_puts(m, " nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
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goto out;
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}
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/* Show the tunnel or session context */
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if (!pd->session) {
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l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
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} else {
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l2tp_dfs_seq_session_show(m, pd->session);
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if (pd->session->deref)
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pd->session->deref(pd->session);
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l2tp_session_dec_refcount(pd->session);
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}
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out:
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return 0;
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}
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static const struct seq_operations l2tp_dfs_seq_ops = {
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.start = l2tp_dfs_seq_start,
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.next = l2tp_dfs_seq_next,
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.stop = l2tp_dfs_seq_stop,
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.show = l2tp_dfs_seq_show,
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};
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static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
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{
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struct l2tp_dfs_seq_data *pd;
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struct seq_file *seq;
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int rc = -ENOMEM;
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pd = kzalloc(sizeof(*pd), GFP_KERNEL);
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if (pd == NULL)
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goto out;
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/* Derive the network namespace from the pid opening the
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* file.
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*/
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pd->net = get_net_ns_by_pid(current->pid);
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if (IS_ERR(pd->net)) {
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rc = PTR_ERR(pd->net);
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goto err_free_pd;
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}
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rc = seq_open(file, &l2tp_dfs_seq_ops);
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if (rc)
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goto err_free_net;
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seq = file->private_data;
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seq->private = pd;
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out:
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return rc;
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err_free_net:
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put_net(pd->net);
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err_free_pd:
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kfree(pd);
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goto out;
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}
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static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
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{
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struct l2tp_dfs_seq_data *pd;
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struct seq_file *seq;
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seq = file->private_data;
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pd = seq->private;
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if (pd->net)
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put_net(pd->net);
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kfree(pd);
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seq_release(inode, file);
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return 0;
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}
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static const struct file_operations l2tp_dfs_fops = {
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.owner = THIS_MODULE,
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.open = l2tp_dfs_seq_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = l2tp_dfs_seq_release,
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};
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static int __init l2tp_debugfs_init(void)
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{
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int rc = 0;
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rootdir = debugfs_create_dir("l2tp", NULL);
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if (IS_ERR(rootdir)) {
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rc = PTR_ERR(rootdir);
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rootdir = NULL;
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goto out;
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}
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tunnels = debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
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if (tunnels == NULL)
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rc = -EIO;
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pr_info("L2TP debugfs support\n");
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out:
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if (rc)
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pr_warn("unable to init\n");
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return rc;
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}
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static void __exit l2tp_debugfs_exit(void)
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{
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debugfs_remove(tunnels);
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debugfs_remove(rootdir);
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}
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module_init(l2tp_debugfs_init);
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module_exit(l2tp_debugfs_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
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MODULE_DESCRIPTION("L2TP debugfs driver");
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MODULE_VERSION("1.0");
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