patch-2.4.18 linux/net/ipv4/netfilter/ipt_ULOG.c

• Lines: 350
• Date: Mon Feb 4 16:43:43 2002
• Orig file: linux.orig/net/ipv4/netfilter/ipt_ULOG.c
• Orig date: Thu Jan 1 00:00:00 1970

diff -Naur -X /home/marcelo/lib/dontdiff linux.orig/net/ipv4/netfilter/ipt_ULOG.c linux/net/ipv4/netfilter/ipt_ULOG.c
@@ -0,0 +1,349 @@
+/*
+ * netfilter module for userspace packet logging daemons
+ *
+ * (C) 2000-2002 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>
+ * 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
+ *
+ * Released under the terms of the GPL
+ *
+ * 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 1.15 2002/01/18 21:33:19 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/timer.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 <linux/netfilter_ipv4/lockhelp.h>
+#include <net/sock.h>
+
+MODULE_LICENSE("GPL");
+
+#define ULOG_NL_EVENT		111		/* Harald's favorite number */
+#define ULOG_MAXNLGROUPS	32		/* numer of nlgroups */
+
+#if 0
+#define DEBUGP(format, args...)	printk(__FILE__ ":" __FUNCTION__ ":" \
+				       format, ## args)
+#else
+#define DEBUGP(format, args...)
+#endif
+
+#define PRINTR(format, args...) do { if (net_ratelimit()) printk(format, ## args); } while (0);
+
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("IP tables userspace logging module");
+
+
+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");
+
+/* 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 nlgroup)
+{
+	ulog_buff_t *ub = &ulog_buffers[nlgroup];
+
+	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 = nlgroup;
+	DEBUGP("ipt_ULOG: throwing %d packets to netlink mask %u\n",
+		ub->qlen, nlgroup);
+	netlink_broadcast(nflognl, ub->skb, 0, nlgroup, 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);
+}
+
+static void nflog_rcv(struct sock *sk, int len)
+{
+	printk("ipt_ULOG:nflog_rcv() did receive netlink message ?!?\n");
+}
+
+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 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_buff_t *ub;
+	ulog_packet_msg_t *pm;
+	size_t size, copy_len;
+	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);
+
+	ub = &ulog_buffers[loginfo->nl_group];
+	
+	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(loginfo->nl_group);
+
+		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);
+
+	/* 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')
+		strncpy(pm->prefix, loginfo->prefix, sizeof(pm->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)
+		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';
+
+	if (copy_len)
+		memcpy(pm->payload, (*pskb)->data, copy_len);
+	
+	/* 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 IPT_CONTINUE;
+
+
+nlmsg_failure:
+	PRINTR("ipt_ULOG: error during NLMSG_PUT\n");
+
+alloc_failure:
+	PRINTR("ipt_ULOG: Error building netlink message\n");
+
+	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;
+	}
+
+	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)
+{
+	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++) {
+		memset(&ulog_buffers[i], 0, sizeof(ulog_buff_t));
+		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, nflog_rcv);
+	if (!nflognl)
+		return -ENOMEM;
+
+	if (ipt_register_target(&ipt_ulog_reg) != 0) {
+		sock_release(nflognl->socket);
+		return -EINVAL;
+	}
+
+	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);