/* * netfilter module for userspace packet logging daemons * * (C) 2000-2002 by Harald Welte <laforge@netfilter.org> * * 2000/09/22 ulog-cprange feature added * 2001/01/04 in-kernel queue as proposed by Sebastian Zander  * 						<zander@fokus.gmd.de> * 2001/01/30 per-rule nlgroup conflicts with global queue.  *            nlgroup now global (sysctl) * 2001/04/19 ulog-queue reworked, now fixed buffer size specified at * 	      module loadtime -HW * 2002/07/07 remove broken nflog_rcv() function -HW * 2002/08/29 fix shifted/unshifted nlgroup bug -HW * 2002/10/30 fix uninitialized mac_len field - <Anders K. Pedersen> * * (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * 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 clock ticks (intel: 100 per second) the queue * should be flushed even if it is not full yet. * * ipt_ULOG.c,v 1.22 2002/10/30 09:07:31 laforge Exp */#include <linux/module.h>#include <linux/config.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/mm.h>#include <linux/netfilter.h>#include <linux/netfilter_ipv4/ip_tables.h>#include <linux/netfilter_ipv4/ipt_ULOG.h>#include <linux/netfilter_ipv4/lockhelp.h>#include <net/sock.h>#include <linux/bitops.h>MODULE_LICENSE("GPL");MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");MODULE_DESCRIPTION("iptables userspace logging module");#define ULOG_NL_EVENT		111		/* Harald's favorite number */#define ULOG_MAXNLGROUPS	32		/* numer of nlgroups */#if 0#define DEBUGP(format, args...) printk("%s:%s:" format, \                                       __FILE__, __FUNCTION__ , ## args)#else#define DEBUGP(format, args...)#endif#define PRINTR(format, args...) do { if (net_ratelimit()) printk(format , ## args); } while (0)static unsigned int nlbufsiz = 4096;MODULE_PARM(nlbufsiz, "i");MODULE_PARM_DESC(nlbufsiz, "netlink buffer size");static unsigned int flushtimeout = 10 * HZ;MODULE_PARM(flushtimeout, "i");MODULE_PARM_DESC(flushtimeout, "buffer flush timeout");static unsigned int nflog = 1;MODULE_PARM(nflog, "i");MODULE_PARM_DESC(nflog, "register as internal netfilter logging module");/* global data structures */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 */} ulog_buff_t;static ulog_buff_t ulog_buffers[ULOG_MAXNLGROUPS];	/* array of buffers */static struct sock *nflognl;	/* our socket */static size_t qlen;		/* current length of multipart-nlmsg */DECLARE_LOCK(ulog_lock);	/* spinlock *//* send one ulog_buff_t to userspace */static void ulog_send(unsigned int nlgroupnum){	ulog_buff_t *ub = &ulog_buffers[nlgroupnum];	if (timer_pending(&ub->timer)) {		DEBUGP("ipt_ULOG: ulog_send: timer was pending, deleting\n");		del_timer(&ub->timer);	}	/* last nlmsg needs NLMSG_DONE */	if (ub->qlen > 1)		ub->lastnlh->nlmsg_type = NLMSG_DONE;	NETLINK_CB(ub->skb).dst_groups = (1 << nlgroupnum);	DEBUGP("ipt_ULOG: throwing %d packets to netlink mask %u\n",		ub->qlen, nlgroup);	netlink_broadcast(nflognl, ub->skb, 0, (1 << nlgroupnum), GFP_ATOMIC);	ub->qlen = 0;	ub->skb = NULL;	ub->lastnlh = NULL;}/* timer function to flush queue in ULOG_FLUSH_INTERVAL time */static void ulog_timer(unsigned long data){	DEBUGP("ipt_ULOG: timer function called, calling ulog_send\n");	/* lock to protect against somebody modifying our structure	 * from ipt_ulog_target at the same time */	LOCK_BH(&ulog_lock);	ulog_send(data);	UNLOCK_BH(&ulog_lock);}struct sk_buff *ulog_alloc_skb(unsigned int size){	struct sk_buff *skb;	/* alloc skb which should be big enough for a whole	 * multipart message. WARNING: has to be <= 131000	 * due to slab allocator restrictions */	skb = alloc_skb(nlbufsiz, GFP_ATOMIC);	if (!skb) {		PRINTR("ipt_ULOG: can't alloc whole buffer %ub!\n",			nlbufsiz);		/* try to allocate only as much as we need for 		 * current packet */		skb = alloc_skb(size, GFP_ATOMIC);		if (!skb)			PRINTR("ipt_ULOG: can't even allocate %ub\n", size);	}	return skb;}static void ipt_ulog_packet(unsigned int hooknum,			    const struct sk_buff *skb,			    const struct net_device *in,			    const struct net_device *out,			    const struct ipt_ulog_info *loginfo,			    const char *prefix){	ulog_buff_t *ub;	ulog_packet_msg_t *pm;	size_t size, copy_len;	struct nlmsghdr *nlh;	/* ffs == find first bit set, necessary because userspace	 * is already shifting groupnumber, but we need unshifted.	 * ffs() returns [1..32], we need [0..31] */	unsigned int groupnum = ffs(loginfo->nl_group) - 1;	/* calculate the size of the skb needed */	if ((loginfo->copy_range == 0) ||	    (loginfo->copy_range > skb->len)) {		copy_len = skb->len;	} else {		copy_len = loginfo->copy_range;	}	size = NLMSG_SPACE(sizeof(*pm) + copy_len);	ub = &ulog_buffers[groupnum];		LOCK_BH(&ulog_lock);	if (!ub->skb) {		if (!(ub->skb = ulog_alloc_skb(size)))			goto alloc_failure;	} else if (ub->qlen >= loginfo->qthreshold ||		   size > skb_tailroom(ub->skb)) {		/* either the queue len is too high or we don't have 		 * enough room in nlskb left. send it to userspace. */		ulog_send(groupnum);		if (!(ub->skb = ulog_alloc_skb(size)))			goto alloc_failure;	}	DEBUGP("ipt_ULOG: qlen %d, qthreshold %d\n", ub->qlen, 		loginfo->qthreshold);	/* NLMSG_PUT contains a hidden goto nlmsg_failure !!! */	nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT, 			size - sizeof(*nlh));	ub->qlen++;	pm = NLMSG_DATA(nlh);	/* We might not have a timestamp, get one */	if (skb->stamp.tv_sec == 0)		do_gettimeofday((struct timeval *)&skb->stamp);	/* copy hook, prefix, timestamp, payload, etc. */	pm->data_len = copy_len;	pm->timestamp_sec = skb->stamp.tv_sec;	pm->timestamp_usec = skb->stamp.tv_usec;	pm->mark = skb->nfmark;	pm->hook = hooknum;	if (prefix != NULL)		strncpy(pm->prefix, prefix, sizeof(pm->prefix));	else if (loginfo->prefix[0] != '\0')		strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix));	else		*(pm->prefix) = '\0';	if (in && in->hard_header_len > 0	    && skb->mac.raw != (void *) skb->nh.iph	    && in->hard_header_len <= ULOG_MAC_LEN) {		memcpy(pm->mac, skb->mac.raw, in->hard_header_len);		pm->mac_len = in->hard_header_len;	} else		pm->mac_len = 0;	if (in)		strncpy(pm->indev_name, in->name, sizeof(pm->indev_name));	else		pm->indev_name[0] = '\0';	if (out)		strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name));	else		pm->outdev_name[0] = '\0';	/* copy_len <= skb->len, so can't fail. */	if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0)		BUG();		/* check if we are building multi-part messages */	if (ub->qlen > 1) {		ub->lastnlh->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;	}	ub->lastnlh = nlh;	/* if timer isn't already running, start it */	if (!timer_pending(&ub->timer)) {		ub->timer.expires = jiffies + flushtimeout;		add_timer(&ub->timer);	}	UNLOCK_BH(&ulog_lock);	return;nlmsg_failure:	PRINTR("ipt_ULOG: error during NLMSG_PUT\n");alloc_failure:	PRINTR("ipt_ULOG: Error building netlink message\n");	UNLOCK_BH(&ulog_lock);}static unsigned int ipt_ulog_target(struct sk_buff **pskb,				    const struct net_device *in,				    const struct net_device *out,				    unsigned int hooknum,				    const void *targinfo, void *userinfo){	struct ipt_ulog_info *loginfo = (struct ipt_ulog_info *) targinfo;	ipt_ulog_packet(hooknum, *pskb, in, out, loginfo, NULL);  	return IPT_CONTINUE;} static void ipt_logfn(unsigned int hooknum,		      const struct sk_buff *skb,		      const struct net_device *in,		      const struct net_device *out,		      const char *prefix){	struct ipt_ulog_info loginfo = { 		.nl_group = ULOG_DEFAULT_NLGROUP,		.copy_range = 0,		.qthreshold = ULOG_DEFAULT_QTHRESHOLD,		.prefix = ""	};	ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix);}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;	}	return 1;}static struct ipt_target ipt_ulog_reg = {	.name		= "ULOG",	.target		= ipt_ulog_target,	.checkentry	= ipt_ulog_checkentry,	.me		= THIS_MODULE,};static int __init init(void){	int i;	DEBUGP("ipt_ULOG: init module\n");	if (nlbufsiz >= 128*1024) {		printk("Netlink buffer has to be <= 128kB\n");		return -EINVAL;	}	/* initialize ulog_buffers */	for (i = 0; i < ULOG_MAXNLGROUPS; i++) {		init_timer(&ulog_buffers[i].timer);		ulog_buffers[i].timer.function = ulog_timer;		ulog_buffers[i].timer.data = i;	}	nflognl = netlink_kernel_create(NETLINK_NFLOG, NULL);	if (!nflognl)		return -ENOMEM;	if (ipt_register_target(&ipt_ulog_reg) != 0) {		sock_release(nflognl->sk_socket);		return -EINVAL;	}	if (nflog)		nf_log_register(PF_INET, &ipt_logfn);		return 0;}static void __exit fini(void){	ulog_buff_t *ub;	int i;	DEBUGP("ipt_ULOG: cleanup_module\n");	if (nflog)		nf_log_unregister(PF_INET, &ipt_logfn);	ipt_unregister_target(&ipt_ulog_reg);	sock_release(nflognl->sk_socket);	/* remove pending timers and free allocated skb's */	for (i = 0; i < ULOG_MAXNLGROUPS; i++) {		ub = &ulog_buffers[i];		if (timer_pending(&ub->timer)) {			DEBUGP("timer was pending, deleting\n");			del_timer(&ub->timer);		}		if (ub->skb) {			kfree_skb(ub->skb);			ub->skb = NULL;		}	}}module_init(init);module_exit(fini);