l2tp_debugfs.c

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/*
 * L2TP subsystem debugfs
 *
 * Copyright (c) 2010 Katalix Systems Ltd
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/hash.h>
#include <linux/l2tp.h>
#include <linux/in.h>
#include <linux/etherdevice.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/inet_common.h>
#include <net/inet_hashtables.h>
#include <net/tcp_states.h>
#include <net/protocol.h>
#include <net/xfrm.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

#include "l2tp_core.h"

static struct dentry *rootdir;
static struct dentry *tunnels;

struct l2tp_dfs_seq_data {
    struct net *net;
    int tunnel_idx;         /* current tunnel */
    int session_idx;        /* index of session within current tunnel */
    struct l2tp_tunnel *tunnel;
    struct l2tp_session *session;   /* NULL means get next tunnel */
};

static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
{
    pd->tunnel = l2tp_tunnel_find_nth(pd->net, pd->tunnel_idx);
    pd->tunnel_idx++;
}

static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
{
    pd->session = l2tp_session_find_nth(pd->tunnel, pd->session_idx);
    pd->session_idx++;

    if (pd->session == NULL) {
        pd->session_idx = 0;
        l2tp_dfs_next_tunnel(pd);
    }

}

static void *l2tp_dfs_seq_start(struct seq_file *m, loff_t *offs)
{
    struct l2tp_dfs_seq_data *pd = SEQ_START_TOKEN;
    loff_t pos = *offs;

    if (!pos)
        goto out;

    BUG_ON(m->private == NULL);
    pd = m->private;

    if (pd->tunnel == NULL)
        l2tp_dfs_next_tunnel(pd);
    else
        l2tp_dfs_next_session(pd);

    /* NULL tunnel and session indicates end of list */
    if ((pd->tunnel == NULL) && (pd->session == NULL))
        pd = NULL;

out:
    return pd;
}


static void *l2tp_dfs_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
    (*pos)++;
    return NULL;
}

static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
{
    /* nothing to do */
}

static void l2tp_dfs_seq_tunnel_show(struct seq_file *m, void *v)
{
    struct l2tp_tunnel *tunnel = v;
    int session_count = 0;
    int hash;
    struct hlist_node *walk;
    struct hlist_node *tmp;

    read_lock_bh(&tunnel->hlist_lock);
    for (hash = 0; hash < L2TP_HASH_SIZE; hash++) {
        hlist_for_each_safe(walk, tmp, &tunnel->session_hlist[hash]) {
            struct l2tp_session *session;

            session = hlist_entry(walk, struct l2tp_session, hlist);
            if (session->session_id == 0)
                continue;

            session_count++;
        }
    }
    read_unlock_bh(&tunnel->hlist_lock);

    seq_printf(m, "\nTUNNEL %u peer %u", tunnel->tunnel_id, tunnel->peer_tunnel_id);
    if (tunnel->sock) {
        struct inet_sock *inet = inet_sk(tunnel->sock);

#if IS_ENABLED(CONFIG_IPV6)
        if (tunnel->sock->sk_family == AF_INET6) {
            struct ipv6_pinfo *np = inet6_sk(tunnel->sock);
            seq_printf(m, " from %pI6c to %pI6c\n",
                &np->saddr, &np->daddr);
        } else
#endif
        seq_printf(m, " from %pI4 to %pI4\n",
               &inet->inet_saddr, &inet->inet_daddr);
        if (tunnel->encap == L2TP_ENCAPTYPE_UDP)
            seq_printf(m, " source port %hu, dest port %hu\n",
                   ntohs(inet->inet_sport), ntohs(inet->inet_dport));
    }
    seq_printf(m, " L2TPv%d, %s\n", tunnel->version,
           tunnel->encap == L2TP_ENCAPTYPE_UDP ? "UDP" :
           tunnel->encap == L2TP_ENCAPTYPE_IP ? "IP" :
           "");
    seq_printf(m, " %d sessions, refcnt %d/%d\n", session_count,
           tunnel->sock ? atomic_read(&tunnel->sock->sk_refcnt) : 0,
           atomic_read(&tunnel->ref_count));

    seq_printf(m, " %08x rx %llu/%llu/%llu rx %llu/%llu/%llu\n",
           tunnel->debug,
           (unsigned long long)tunnel->stats.tx_packets,
           (unsigned long long)tunnel->stats.tx_bytes,
           (unsigned long long)tunnel->stats.tx_errors,
           (unsigned long long)tunnel->stats.rx_packets,
           (unsigned long long)tunnel->stats.rx_bytes,
           (unsigned long long)tunnel->stats.rx_errors);

    if (tunnel->show != NULL)
        tunnel->show(m, tunnel);
}

static void l2tp_dfs_seq_session_show(struct seq_file *m, void *v)
{
    struct l2tp_session *session = v;

    seq_printf(m, "  SESSION %u, peer %u, %s\n", session->session_id,
           session->peer_session_id,
           session->pwtype == L2TP_PWTYPE_ETH ? "ETH" :
           session->pwtype == L2TP_PWTYPE_PPP ? "PPP" :
           "");
    if (session->send_seq || session->recv_seq)
        seq_printf(m, "   nr %hu, ns %hu\n", session->nr, session->ns);
    seq_printf(m, "   refcnt %d\n", atomic_read(&session->ref_count));
    seq_printf(m, "   config %d/%d/%c/%c/%s/%s %08x %u\n",
           session->mtu, session->mru,
           session->recv_seq ? 'R' : '-',
           session->send_seq ? 'S' : '-',
           session->data_seq == 1 ? "IPSEQ" :
           session->data_seq == 2 ? "DATASEQ" : "-",
           session->lns_mode ? "LNS" : "LAC",
           session->debug,
           jiffies_to_msecs(session->reorder_timeout));
    seq_printf(m, "   offset %hu l2specific %hu/%hu\n",
           session->offset, session->l2specific_type, session->l2specific_len);
    if (session->cookie_len) {
        seq_printf(m, "   cookie %02x%02x%02x%02x",
               session->cookie[0], session->cookie[1],
               session->cookie[2], session->cookie[3]);
        if (session->cookie_len == 8)
            seq_printf(m, "%02x%02x%02x%02x",
                   session->cookie[4], session->cookie[5],
                   session->cookie[6], session->cookie[7]);
        seq_printf(m, "\n");
    }
    if (session->peer_cookie_len) {
        seq_printf(m, "   peer cookie %02x%02x%02x%02x",
               session->peer_cookie[0], session->peer_cookie[1],
               session->peer_cookie[2], session->peer_cookie[3]);
        if (session->peer_cookie_len == 8)
            seq_printf(m, "%02x%02x%02x%02x",
                   session->peer_cookie[4], session->peer_cookie[5],
                   session->peer_cookie[6], session->peer_cookie[7]);
        seq_printf(m, "\n");
    }

    seq_printf(m, "   %hu/%hu tx %llu/%llu/%llu rx %llu/%llu/%llu\n",
           session->nr, session->ns,
           (unsigned long long)session->stats.tx_packets,
           (unsigned long long)session->stats.tx_bytes,
           (unsigned long long)session->stats.tx_errors,
           (unsigned long long)session->stats.rx_packets,
           (unsigned long long)session->stats.rx_bytes,
           (unsigned long long)session->stats.rx_errors);

    if (session->show != NULL)
        session->show(m, session);
}

static int l2tp_dfs_seq_show(struct seq_file *m, void *v)
{
    struct l2tp_dfs_seq_data *pd = v;

    /* display header on line 1 */
    if (v == SEQ_START_TOKEN) {
        seq_puts(m, "TUNNEL ID, peer ID from IP to IP\n");
        seq_puts(m, " L2TPv2/L2TPv3, UDP/IP\n");
        seq_puts(m, " sessions session-count, refcnt refcnt/sk->refcnt\n");
        seq_puts(m, " debug tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
        seq_puts(m, "  SESSION ID, peer ID, PWTYPE\n");
        seq_puts(m, "   refcnt cnt\n");
        seq_puts(m, "   offset OFFSET l2specific TYPE/LEN\n");
        seq_puts(m, "   [ cookie ]\n");
        seq_puts(m, "   [ peer cookie ]\n");
        seq_puts(m, "   config mtu/mru/rcvseq/sendseq/dataseq/lns debug reorderto\n");
        seq_puts(m, "   nr/ns tx-pkts/bytes/errs rx-pkts/bytes/errs\n");
        goto out;
    }

    /* Show the tunnel or session context */
    if (pd->session == NULL)
        l2tp_dfs_seq_tunnel_show(m, pd->tunnel);
    else
        l2tp_dfs_seq_session_show(m, pd->session);

out:
    return 0;
}

static const struct seq_operations l2tp_dfs_seq_ops = {
    .start      = l2tp_dfs_seq_start,
    .next       = l2tp_dfs_seq_next,
    .stop       = l2tp_dfs_seq_stop,
    .show       = l2tp_dfs_seq_show,
};

static int l2tp_dfs_seq_open(struct inode *inode, struct file *file)
{
    struct l2tp_dfs_seq_data *pd;
    struct seq_file *seq;
    int rc = -ENOMEM;

    pd = kzalloc(sizeof(*pd), GFP_KERNEL);
    if (pd == NULL)
        goto out;

    /* Derive the network namespace from the pid opening the
     * file.
     */
    pd->net = get_net_ns_by_pid(current->pid);
    if (IS_ERR(pd->net)) {
        rc = PTR_ERR(pd->net);
        goto err_free_pd;
    }

    rc = seq_open(file, &l2tp_dfs_seq_ops);
    if (rc)
        goto err_free_net;

    seq = file->private_data;
    seq->private = pd;

out:
    return rc;

err_free_net:
    put_net(pd->net);
err_free_pd:
    kfree(pd);
    goto out;
}

static int l2tp_dfs_seq_release(struct inode *inode, struct file *file)
{
    struct l2tp_dfs_seq_data *pd;
    struct seq_file *seq;

    seq = file->private_data;
    pd = seq->private;
    if (pd->net)
        put_net(pd->net);
    kfree(pd);
    seq_release(inode, file);

    return 0;
}

static const struct file_operations l2tp_dfs_fops = {
    .owner      = THIS_MODULE,
    .open       = l2tp_dfs_seq_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = l2tp_dfs_seq_release,
};

static int __init l2tp_debugfs_init(void)
{
    int rc = 0;

    rootdir = debugfs_create_dir("l2tp", NULL);
    if (IS_ERR(rootdir)) {
        rc = PTR_ERR(rootdir);
        rootdir = NULL;
        goto out;
    }

    tunnels = debugfs_create_file("tunnels", 0600, rootdir, NULL, &l2tp_dfs_fops);
    if (tunnels == NULL)
        rc = -EIO;

    pr_info("L2TP debugfs support\n");

out:
    if (rc)
        pr_warn("unable to init\n");

    return rc;
}

static void __exit l2tp_debugfs_exit(void)
{
    debugfs_remove(tunnels);
    debugfs_remove(rootdir);
}

module_init(l2tp_debugfs_init);
module_exit(l2tp_debugfs_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Chapman <[email protected]>");
MODULE_DESCRIPTION("L2TP debugfs driver");
MODULE_VERSION("1.0");