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/*
* netfilter module for userspace bridged Ethernet frames logging daemons
*
* Authors:
* Bart De Schuymer <bdschuym@pandora.be>
* Harald Welte <laforge@netfilter.org>
*
* November, 2004
*
* Based on ipt_ULOG.c, which is
* (C) 2000-2002 by Harald Welte <laforge@netfilter.org>
*
* This module accepts two parameters:
*
* nlbufsiz:
* The parameter specifies how big the buffer for each netlink multicast
* group is. e.g. If you say nlbufsiz=8192, up to eight kb of packets will
* get accumulated in the kernel until they are sent to userspace. It is
* NOT possible to allocate more than 128kB, and it is strongly discouraged,
* because atomically allocating 128kB inside the network rx softirq is not
* reliable. Please also keep in mind that this buffer size is allocated for
* each nlgroup you are using, so the total kernel memory usage increases
* by that factor.
*
* flushtimeout:
* Specify, after how many hundredths of a second the queue should be
* flushed even if it is not full yet.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/netlink.h>
#include <linux/netdevice.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/netfilter_bridge/ebt_ulog.h>
#include <net/netfilter/nf_log.h>
#include <net/sock.h>
#include "../br_private.h"
static unsigned int nlbufsiz = NLMSG_GOODSIZE;
module_param(nlbufsiz, uint, 0600);
MODULE_PARM_DESC(nlbufsiz, "netlink buffer size (number of bytes) "
"(defaults to 4096)");
static unsigned int flushtimeout = 10;
module_param(flushtimeout, uint, 0600);
MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths ofa second) "
"(defaults to 10)");
typedef struct {
unsigned int qlen; /* number of nlmsgs' in the skb */
struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */
struct sk_buff *skb; /* the pre-allocated skb */
struct timer_list timer; /* the timer function */
spinlock_t lock; /* the per-queue lock */
} ebt_ulog_buff_t;
static ebt_ulog_buff_t ulog_buffers[EBT_ULOG_MAXNLGROUPS];
static struct sock *ebtulognl;
/* send one ulog_buff_t to userspace */
static void ulog_send(unsigned int nlgroup)
{
ebt_ulog_buff_t *ub = &ulog_buffers[nlgroup];
if (timer_pending(&ub->timer))
del_timer(&ub->timer);
if (!ub->skb)
return;
/* last nlmsg needs NLMSG_DONE */
if (ub->qlen > 1)
ub->lastnlh->nlmsg_type = NLMSG_DONE;
NETLINK_CB(ub->skb).dst_group = nlgroup + 1;
netlink_broadcast(ebtulognl, ub->skb, 0, nlgroup + 1, GFP_ATOMIC);
ub->qlen = 0;
ub->skb = NULL;
}
/* timer function to flush queue in flushtimeout time */
static void ulog_timer(unsigned long data)
{
spin_lock_bh(&ulog_buffers[data].lock);
if (ulog_buffers[data].skb)
ulog_send(data);
spin_unlock_bh(&ulog_buffers[data].lock);
}
static struct sk_buff *ulog_alloc_skb(unsigned int size)
{
struct sk_buff *skb;
unsigned int n;
n = max(size, nlbufsiz);
skb = alloc_skb(n, GFP_ATOMIC);
if (!skb) {
pr_debug("cannot alloc whole buffer of size %ub!\n", n);
if (n > size) {
/* try to allocate only as much as we need for
* current packet */
skb = alloc_skb(size, GFP_ATOMIC);
if (!skb)
pr_debug("cannot even allocate "
"buffer of size %ub\n", size);
}
}
return skb;
}
static void ebt_ulog_packet(unsigned int hooknr, const struct sk_buff *skb,
const struct net_device *in, const struct net_device *out,
const struct ebt_ulog_info *uloginfo, const char *prefix)
{
ebt_ulog_packet_msg_t *pm;
size_t size, copy_len;
struct nlmsghdr *nlh;
unsigned int group = uloginfo->nlgroup;
ebt_ulog_buff_t *ub = &ulog_buffers[group];
spinlock_t *lock = &ub->lock;
ktime_t kt;
if ((uloginfo->cprange == 0) ||
(uloginfo->cprange > skb->len + ETH_HLEN))
copy_len = skb->len + ETH_HLEN;
else
copy_len = uloginfo->cprange;
size = NLMSG_SPACE(sizeof(*pm) + copy_len);
if (size > nlbufsiz) {
pr_debug("Size %Zd needed, but nlbufsiz=%d\n", size, nlbufsiz);
return;
}
spin_lock_bh(lock);
if (!ub->skb) {
if (!(ub->skb = ulog_alloc_skb(size)))
goto alloc_failure;
} else if (size > skb_tailroom(ub->skb)) {
ulog_send(group);
if (!(ub->skb = ulog_alloc_skb(size)))
goto alloc_failure;
}
nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, 0,
size - NLMSG_ALIGN(sizeof(*nlh)));
ub->qlen++;
pm = NLMSG_DATA(nlh);
/* Fill in the ulog data */
pm->version = EBT_ULOG_VERSION;
kt = ktime_get_real();
pm->stamp = ktime_to_timeval(kt);
if (ub->qlen == 1)
ub->skb->tstamp = kt;
pm->data_len = copy_len;
pm->mark = skb->mark;
pm->hook = hooknr;
if (uloginfo->prefix != NULL)
strcpy(pm->prefix, uloginfo->prefix);
else
*(pm->prefix) = '\0';
if (in) {
strcpy(pm->physindev, in->name);
/* If in isn't a bridge, then physindev==indev */
if (in->br_port)
strcpy(pm->indev, in->br_port->br->dev->name);
else
strcpy(pm->indev, in->name);
} else
pm->indev[0] = pm->physindev[0] = '\0';
if (out) {
/* If out exists, then out is a bridge port */
strcpy(pm->physoutdev, out->name);
strcpy(pm->outdev, out->br_port->br->dev->name);
} else
pm->outdev[0] = pm->physoutdev[0] = '\0';
if (skb_copy_bits(skb, -ETH_HLEN, pm->data, copy_len) < 0)
BUG();
if (ub->qlen > 1)
ub->lastnlh->nlmsg_flags |= NLM_F_MULTI;
ub->lastnlh = nlh;
if (ub->qlen >= uloginfo->qthreshold)
ulog_send(group);
else if (!timer_pending(&ub->timer)) {
ub->timer.expires = jiffies + flushtimeout * HZ / 100;
add_timer(&ub->timer);
}
unlock:
spin_unlock_bh(lock);
return;
nlmsg_failure:
pr_debug("error during NLMSG_PUT. This should "
"not happen, please report to author.\n");
goto unlock;
alloc_failure:
goto unlock;
}
/* this function is registered with the netfilter core */
static void ebt_log_packet(u_int8_t pf, unsigned int hooknum,
const struct sk_buff *skb, const struct net_device *in,
const struct net_device *out, const struct nf_loginfo *li,
const char *prefix)
{
struct ebt_ulog_info loginfo;
if (!li || li->type != NF_LOG_TYPE_ULOG) {
loginfo.nlgroup = EBT_ULOG_DEFAULT_NLGROUP;
loginfo.cprange = 0;
loginfo.qthreshold = EBT_ULOG_DEFAULT_QTHRESHOLD;
loginfo.prefix[0] = '\0';
} else {
loginfo.nlgroup = li->u.ulog.group;
loginfo.cprange = li->u.ulog.copy_len;
loginfo.qthreshold = li->u.ulog.qthreshold;
strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix));
}
ebt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix);
}
static unsigned int
ebt_ulog_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
ebt_ulog_packet(par->hooknum, skb, par->in, par->out,
par->targinfo, NULL);
return EBT_CONTINUE;
}
static int ebt_ulog_tg_check(const struct xt_tgchk_param *par)
{
struct ebt_ulog_info *uloginfo = par->targinfo
|