1 files changed, 442 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
new file mode 100644
index 00000000..446e0f46
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_ULOG.c
@@ -0,0 +1,442 @@
+/*
+ * netfilter module for userspace packet logging daemons
+ *
+ * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
+ * (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.
+ *
+ * Actually you should use nlbufsiz a bit smaller than PAGE_SIZE, since
+ * nlbufsiz is used with alloc_skb, which adds another
+ * sizeof(struct skb_shared_info).  Use NLMSG_GOODSIZE instead.
+ *
+ * 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/spinlock.h>
+#include <linux/socket.h>
+#include <linux/slab.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/moduleparam.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv4/ipt_ULOG.h>
+#include <net/netfilter/nf_log.h>
+#include <net/sock.h>
+#include <linux/bitops.h>
+#include <asm/unaligned.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("Xtables: packet logging to netlink using ULOG");
+MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NFLOG);
+
+#define ULOG_NL_EVENT		111		/* Harald's favorite number */
+#define ULOG_MAXNLGROUPS	32		/* numer of nlgroups */
+
+static unsigned int nlbufsiz = NLMSG_GOODSIZE;
+module_param(nlbufsiz, uint, 0400);
+MODULE_PARM_DESC(nlbufsiz, "netlink buffer size");
+
+static unsigned int flushtimeout = 10;
+module_param(flushtimeout, uint, 0600);
+MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)");
+
+static int nflog = 1;
+module_param(nflog, bool, 0400);
+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 DEFINE_SPINLOCK(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)) {
+		pr_debug("ulog_send: timer was pending, deleting\n");
+		del_timer(&ub->timer);
+	}
+
+	if (!ub->skb) {
+		pr_debug("ulog_send: nothing to send\n");
+		return;
+	}
+
+	/* last nlmsg needs NLMSG_DONE */
+	if (ub->qlen > 1)
+		ub->lastnlh->nlmsg_type = NLMSG_DONE;
+
+	NETLINK_CB(ub->skb).dst_group = nlgroupnum + 1;
+	pr_debug("throwing %d packets to netlink group %u\n",
+		 ub->qlen, nlgroupnum + 1);
+	netlink_broadcast(nflognl, ub->skb, 0, nlgroupnum + 1, GFP_ATOMIC);
+
+	ub->qlen = 0;
+	ub->skb = NULL;
+	ub->lastnlh = NULL;
+}
+
+
+/* timer function to flush queue in flushtimeout time */
+static void ulog_timer(unsigned long data)
+{
+	pr_debug("timer function called, calling ulog_send\n");
+
+	/* lock to protect against somebody modifying our structure
+	 * from ipt_ulog_target at the same time */
+	spin_lock_bh(&ulog_lock);
+	ulog_send(data);
+	spin_unlock_bh(&ulog_lock);
+}
+
+static struct sk_buff *ulog_alloc_skb(unsigned int size)
+{
+	struct sk_buff *skb;
+	unsigned int n;
+
+	/* alloc skb which should be big enough for a whole
+	 * multipart message. WARNING: has to be <= 131000
+	 * due to slab allocator restrictions */
+
+	n = max(size, nlbufsiz);
+	skb = alloc_skb(n, GFP_ATOMIC);
+	if (!skb) {
+		pr_debug("cannot alloc whole buffer %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 %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;
+	struct timeval tv;
+
+	/* 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];
+
+	spin_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;
+	}
+
+	pr_debug("qlen %d, qthreshold %Zu\n", ub->qlen, loginfo->qthreshold);
+
+	/* NLMSG_PUT contains a hidden goto nlmsg_failure !!! */
+	nlh = NLMSG_PUT(ub->skb, 0, ub->qlen, ULOG_NL_EVENT,
+			sizeof(*pm)+copy_len);
+	ub->qlen++;
+
+	pm = NLMSG_DATA(nlh);
+
+	/* We might not have a timestamp, get one */
+	if (skb->tstamp.tv64 == 0)
+		__net_timestamp((struct sk_buff *)skb);
+
+	/* copy hook, prefix, timestamp, payload, etc. */
+	pm->data_len = copy_len;
+	tv = ktime_to_timeval(skb->tstamp);
+	put_unaligned(tv.tv_sec, &pm->timestamp_sec);
+	put_unaligned(tv.tv_usec, &pm->timestamp_usec);
+	put_unaligned(skb->mark, &pm->mark);
+	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_header != skb->network_header &&
+	    in->hard_header_len <= ULOG_MAC_LEN) {
+		memcpy(pm->mac, skb_mac_header(skb), 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;
+
+	ub->lastnlh = nlh;
+
+	/* if timer isn't already running, start it */
+	if (!timer_pending(&ub->timer)) {
+		ub->timer.expires = jiffies + flushtimeout * HZ / 100;
+		add_timer(&ub->timer);
+	}
+
+	/* if threshold is reached, send message to userspace */
+	if (ub->qlen >= loginfo->qthreshold) {
+		if (loginfo->qthreshold > 1)
+			nlh->nlmsg_type = NLMSG_DONE;
+		ulog_send(groupnum);
+	}
+
+	spin_unlock_bh(&ulog_lock);
+
+	return;
+
+nlmsg_failure:
+	pr_debug("error during NLMSG_PUT\n");
+alloc_failure:
+	pr_debug("Error building netlink message\n");
+	spin_unlock_bh(&ulog_lock);
+}
+
+static unsigned int
+ulog_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	ipt_ulog_packet(par->hooknum, skb, par->in, par->out,
+	                par->targinfo, NULL);
+	return XT_CONTINUE;
+}
+
+static void ipt_logfn(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 ipt_ulog_info loginfo;
+
+	if (!li || li->type != NF_LOG_TYPE_ULOG) {
+		loginfo.nl_group = ULOG_DEFAULT_NLGROUP;
+		loginfo.copy_range = 0;
+		loginfo.qthreshold = ULOG_DEFAULT_QTHRESHOLD;
+		loginfo.prefix[0] = '\0';
+	} else {
+		loginfo.nl_group = li->u.ulog.group;
+		loginfo.copy_range = li->u.ulog.copy_len;
+		loginfo.qthreshold = li->u.ulog.qthreshold;
+		strlcpy(loginfo.prefix, prefix, sizeof(loginfo.prefix));
+	}
+
+	ipt_ulog_packet(hooknum, skb, in, out, &loginfo, prefix);
+}
+
+static int ulog_tg_check(const struct xt_tgchk_param *par)
+{
+	const struct ipt_ulog_info *loginfo = par->targinfo;
+
+	if (loginfo->prefix[sizeof(loginfo->prefix) - 1] != '\0') {
+		pr_debug("prefix not null-terminated\n");
+		return -EINVAL;
+	}
+	if (loginfo->qthreshold > ULOG_MAX_QLEN) {
+		pr_debug("queue threshold %Zu > MAX_QLEN\n",
+			 loginfo->qthreshold);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+#ifdef CONFIG_COMPAT
+struct compat_ipt_ulog_info {
+	compat_uint_t	nl_group;
+	compat_size_t	copy_range;
+	compat_size_t	qthreshold;
+	char		prefix[ULOG_PREFIX_LEN];
+};
+
+static void ulog_tg_compat_from_user(void *dst, const void *src)
+{
+	const struct compat_ipt_ulog_info *cl = src;
+	struct ipt_ulog_info l = {
+		.nl_group	= cl->nl_group,
+		.copy_range	= cl->copy_range,
+		.qthreshold	= cl->qthreshold,
+	};
+
+	memcpy(l.prefix, cl->prefix, sizeof(l.prefix));
+	memcpy(dst, &l, sizeof(l));
+}
+
+static int ulog_tg_compat_to_user(void __user *dst, const void *src)
+{
+	const struct ipt_ulog_info *l = src;
+	struct compat_ipt_ulog_info cl = {
+		.nl_group	= l->nl_group,
+		.copy_range	= l->copy_range,
+		.qthreshold	= l->qthreshold,
+	};
+
+	memcpy(cl.prefix, l->prefix, sizeof(cl.prefix));
+	return copy_to_user(dst, &cl, sizeof(cl)) ? -EFAULT : 0;
+}
+#endif /* CONFIG_COMPAT */
+
+static struct xt_target ulog_tg_reg __read_mostly = {
+	.name		= "ULOG",
+	.family		= NFPROTO_IPV4,
+	.target		= ulog_tg,
+	.targetsize	= sizeof(struct ipt_ulog_info),
+	.checkentry	= ulog_tg_check,
+#ifdef CONFIG_COMPAT
+	.compatsize	= sizeof(struct compat_ipt_ulog_info),
+	.compat_from_user = ulog_tg_compat_from_user,
+	.compat_to_user	= ulog_tg_compat_to_user,
+#endif
+	.me		= THIS_MODULE,
+};
+
+static struct nf_logger ipt_ulog_logger __read_mostly = {
+	.name		= "ipt_ULOG",
+	.logfn		= ipt_logfn,
+	.me		= THIS_MODULE,
+};
+
+static int __init ulog_tg_init(void)
+{
+	int ret, i;
+
+	pr_debug("init module\n");
+
+	if (nlbufsiz > 128*1024) {
+		pr_warning("Netlink buffer has to be <= 128kB\n");
+		return -EINVAL;
+	}
+
+	/* initialize ulog_buffers */
+	for (i = 0; i < ULOG_MAXNLGROUPS; i++)
+		setup_timer(&ulog_buffers[i].timer, ulog_timer, i);
+
+	nflognl = netlink_kernel_create(&init_net,
+					NETLINK_NFLOG, ULOG_MAXNLGROUPS, NULL,
+					NULL, THIS_MODULE);
+	if (!nflognl)
+		return -ENOMEM;
+
+	ret = xt_register_target(&ulog_tg_reg);
+	if (ret < 0) {
+		netlink_kernel_release(nflognl);
+		return ret;
+	}
+	if (nflog)
+		nf_log_register(NFPROTO_IPV4, &ipt_ulog_logger);
+
+	return 0;
+}
+
+static void __exit ulog_tg_exit(void)
+{
+	ulog_buff_t *ub;
+	int i;
+
+	pr_debug("cleanup_module\n");
+
+	if (nflog)
+		nf_log_unregister(&ipt_ulog_logger);
+	xt_unregister_target(&ulog_tg_reg);
+	netlink_kernel_release(nflognl);
+
+	/* remove pending timers and free allocated skb's */
+	for (i = 0; i < ULOG_MAXNLGROUPS; i++) {
+		ub = &ulog_buffers[i];
+		if (timer_pending(&ub->timer)) {
+			pr_debug("timer was pending, deleting\n");
+			del_timer(&ub->timer);
+		}
+
+		if (ub->skb) {
+			kfree_skb(ub->skb);
+			ub->skb = NULL;
+		}
+	}
+}
+
+module_init(ulog_tg_init);
+module_exit(ulog_tg_exit);