1 files changed, 342 insertions, 0 deletions

diff --git a/net/bridge/netfilter/ebt_ulog.c b/net/bridge/netfilter/ebt_ulog.c
new file mode 100644
index 00000000..26377e96
--- /dev/null
+++ b/net/bridge/netfilter/ebt_ulog.c
@@ -0,0 +1,342 @@
+/*
+ * 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 (br_port_exists(in))
+			/* rcu_read_lock()ed by nf_hook_slow */
+			strcpy(pm->indev, br_port_get_rcu(in)->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);
+		/* rcu_read_lock()ed by nf_hook_slow */
+		strcpy(pm->outdev, br_port_get_rcu(out)->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;
+
+	if (uloginfo->nlgroup > 31)
+		return -EINVAL;
+
+	uloginfo->prefix[EBT_ULOG_PREFIX_LEN - 1] = '\0';
+
+	if (uloginfo->qthreshold > EBT_ULOG_MAX_QLEN)
+		uloginfo->qthreshold = EBT_ULOG_MAX_QLEN;
+
+	return 0;
+}
+
+static struct xt_target ebt_ulog_tg_reg __read_mostly = {
+	.name		= "ulog",
+	.revision	= 0,
+	.family		= NFPROTO_BRIDGE,
+	.target		= ebt_ulog_tg,
+	.checkentry	= ebt_ulog_tg_check,
+	.targetsize	= sizeof(struct ebt_ulog_info),
+	.me		= THIS_MODULE,
+};
+
+static struct nf_logger ebt_ulog_logger __read_mostly = {
+	.name		= "ebt_ulog",
+	.logfn		= &ebt_log_packet,
+	.me		= THIS_MODULE,
+};
+
+static int __init ebt_ulog_init(void)
+{
+	int ret;
+	int i;
+
+	if (nlbufsiz >= 128*1024) {
+		pr_warning("Netlink buffer has to be <= 128kB,"
+			   " please try a smaller nlbufsiz parameter.\n");
+		return -EINVAL;
+	}
+
+	/* initialize ulog_buffers */
+	for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
+		setup_timer(&ulog_buffers[i].timer, ulog_timer, i);
+		spin_lock_init(&ulog_buffers[i].lock);
+	}
+
+	ebtulognl = netlink_kernel_create(&init_net, NETLINK_NFLOG,
+					  EBT_ULOG_MAXNLGROUPS, NULL, NULL,
+					  THIS_MODULE);
+	if (!ebtulognl)
+		ret = -ENOMEM;
+	else if ((ret = xt_register_target(&ebt_ulog_tg_reg)) != 0)
+		netlink_kernel_release(ebtulognl);
+
+	if (ret == 0)
+		nf_log_register(NFPROTO_BRIDGE, &ebt_ulog_logger);
+
+	return ret;
+}
+
+static void __exit ebt_ulog_fini(void)
+{
+	ebt_ulog_buff_t *ub;
+	int i;
+
+	nf_log_unregister(&ebt_ulog_logger);
+	xt_unregister_target(&ebt_ulog_tg_reg);
+	for (i = 0; i < EBT_ULOG_MAXNLGROUPS; i++) {
+		ub = &ulog_buffers[i];
+		if (timer_pending(&ub->timer))
+			del_timer(&ub->timer);
+		spin_lock_bh(&ub->lock);
+		if (ub->skb) {
+			kfree_skb(ub->skb);
+			ub->skb = NULL;
+		}
+		spin_unlock_bh(&ub->lock);
+	}
+	netlink_kernel_release(ebtulognl);
+}
+
+module_init(ebt_ulog_init);
+module_exit(ebt_ulog_fini);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
+MODULE_DESCRIPTION("Ebtables: Packet logging to netlink using ULOG");