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/*
* netfilter module for userspace packet logging daemons
*
* (C) 2000 by Harald Welte <laforge@gnumonks.org>
*
* 2000/09/22 ulog-cprange feature added
* 2001/01/04 in-kernel queue as proposed by Sebastian Zander
* <zander@fokus.gmd.de>
*
* Released under the terms of the GPL
*
* $Id: ipt_ULOG.c,v 1.7 2001/01/30 09:27:31 laforge Exp $
*/
#include <linux/module.h>
#include <linux/version.h>
#include <linux/config.h>
#include <linux/spinlock.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/kernel.h>
#include <linux/netlink.h>
#include <linux/netdevice.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_ULOG.h>
#include <net/sock.h>
#define ULOG_NL_EVENT 111 /* Harald's favorite number */
#define ULOG_SLAB_MAX 100000 /* from mm/slab.c: 131072 */
#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif
MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
MODULE_DESCRIPTION("IP tables userspace logging module");
static struct sock *nflognl; /* our socket */
static struct sk_buff *nlskb; /* the skb containing the nlmsg */
static size_t qlen; /* current length of multipart-nlmsg */
static size_t max_size; /* maximum gross size of one packet */
static size_t max_qthresh; /* maximum queue threshold of all rules */
static spinlock_t ulog_lock; /* spinlock */
static void nflog_rcv(struct sock *sk, int len)
{
printk("ipt_ULOG:nflog_rcv() did receive netlink message ?!?\n");
}
static unsigned int ipt_ulog_target(struct sk_buff **pskb,
unsigned int hooknum,
const struct net_device *in,
const struct net_device *out,
const void *targinfo, void *userinfo)
{
ulog_packet_msg_t *pm;
size_t size, copy_len;
struct sk_buff *newskb = NULL;
struct nlmsghdr *nlh;
struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo;
/* calculate the size of the skb needed */
if ((loginfo->copy_range == 0) ||
(loginfo->copy_range > (*pskb)->len)) {
copy_len = (*pskb)->len;
} else {
copy_len = loginfo->copy_range;
}
size = NLMSG_SPACE(sizeof(*pm) + copy_len);
spin_lock_bh(ulog_lock);
if ((qlen == 0) || (!nlskb)) {
/* alloc skb which should be big enough for a whole
* multipart message. WARNING: has to be <= 131000
* due to slab allocator restrictions */
nlskb = alloc_skb((max_qthresh * max_size), GFP_ATOMIC);
} else if (size > skb_tailroom(nlskb)) {
DEBUGP("ipt_ULOG: copy expand %d %d\n",
skb_tailroom(nlskb), size);
newskb = skb_copy_expand(nlskb, skb_headroom(nlskb),
size, GFP_ATOMIC);
if (!newskb) {
printk("ipt_ULOG: OOM\n");
goto oom_failure;
}
kfree_skb(nlskb);
nlskb = newskb;
}
if (!nlskb)
goto nlmsg_failure;
DEBUGP("ipt_ULOG: qlen %d, qthreshold %d\n", qlen, loginfo->qthreshold);
nlh = NLMSG_PUT(nlskb, 0, qlen, ULOG_NL_EVENT, size - sizeof(*nlh));
qlen++;
pm = NLMSG_DATA(nlh);
/* copy hook, prefix, timestamp, payload, etc. */
pm->data_len = copy_len;
pm->timestamp_sec = (*pskb)->stamp.tv_sec;
pm->timestamp_usec = (*pskb)->stamp.tv_usec;
pm->mark = (*pskb)->nfmark;
pm->hook = hooknum;
if (loginfo->prefix[0] != '\0')
strcpy(pm->prefix, loginfo->prefix);
else
*(pm->prefix) = '\0';
if (in && in->hard_header_len > 0
&& (*pskb)->mac.raw != (void *) (*pskb)->nh.iph
&& in->hard_header_len <= ULOG_MAC_LEN) {
memcpy(pm->mac, (*pskb)->mac.raw, in->hard_header_len);
pm->mac_len = in->hard_header_len;
}
if (in)
strcpy(pm->indev_name, in->name);
else
pm->indev_name[0] = '\0';
if (out)
strcpy(pm->outdev_name, out->name);
else
pm->outdev_name[0] = '\0';
if (copy_len)
memcpy(pm->payload, (*pskb)->data, copy_len);
/* check if we are building multi-part messages */
if (loginfo->qthreshold > 1) {
nlh->nlmsg_flags |= NLM_F_MULTI;
}
/* if threshold is reached, send message to userspace */
if (qlen >= loginfo->qthreshold) {
if (loginfo->qthreshold > 1)
nlh->nlmsg_type = NLMSG_DONE;
NETLINK_CB(nlskb).dst_groups = loginfo->nl_group;
DEBUGP("ipt_ULOG: throwing %d packets to netlink mask %u\n",
qlen, loginfo->nl_group);
netlink_broadcast(nflognl, nlskb, 0, loginfo->nl_group,
GFP_ATOMIC);
qlen = 0;
nlskb = NULL;
}
spin_unlock_bh(ulog_lock);
return IPT_CONTINUE;
oom_failure:
if (newskb)
kfree_skb(newskb);
nlmsg_failure:
if (nlskb) {
kfree(nlskb);
nlskb = NULL;
}
printk("ipt_ULOG: Error building netlink message\n");
spin_unlock_bh(ulog_lock);
return IPT_CONTINUE;
}
static int ipt_ulog_checkentry(const char *tablename,
const struct ipt_entry *e,
void *targinfo,
unsigned int targinfosize,
unsigned int hookmask)
{
struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo;
if (targinfosize != IPT_ALIGN(sizeof(struct ipt_ulog_info))) {
DEBUGP("ipt_ULOG: targinfosize %u != 0\n", targinfosize);
return 0;
}
if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') {
DEBUGP("ipt_ULOG: prefix term %i\n",
loginfo->prefix[sizeof(loginfo->prefix) - 1]);
return 0;
}
if (loginfo->qthreshold > ULOG_MAX_QLEN) {
DEBUGP("ipt_ULOG: queue threshold %i > MAX_QLEN\n",
loginfo->qthreshold);
return 0;
}
if (loginfo->qthreshold > max_qthresh) {
if (loginfo->qthreshold * max_size > ULOG_SLAB_MAX) {
DEBUGP("ipt_ULOG: qthresh too big\n");
return 0;
}
DEBUGP("ipt_ULOG: increasing max_qthresh to %u\n",
loginfo->qthreshold);
max_qthresh = loginfo->qthreshold;
}
return 1;
}
static struct ipt_target ipt_ulog_reg =
{ {NULL, NULL}, "ULOG", ipt_ulog_target, ipt_ulog_checkentry, NULL,
THIS_MODULE
};
static int __init init(void)
{
DEBUGP("ipt_ULOG: init module\n");
nflognl = netlink_kernel_create(NETLINK_NFLOG, nflog_rcv);
if (!nflognl)
return -ENOMEM;
if (ipt_register_target(&ipt_ulog_reg) != 0) {
sock_release(nflognl->socket);
return -EINVAL;
}
/* FIXME: does anybody know an easy way to determine the biggest
* MTU of all interfaces in the system ? */
max_size = 1500;
spin_lock_init(ulog_lock);
return 0;
}
static void __exit fini(void)
{
DEBUGP("ipt_ULOG: cleanup_module\n");
ipt_unregister_target(&ipt_ulog_reg);
sock_release(nflognl->socket);
}
module_init(init);
module_exit(fini);
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