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Diffstat (limited to 'net/ipv4/netfilter/ipt_ULOG.c')
-rw-r--r--net/ipv4/netfilter/ipt_ULOG.c419
1 files changed, 419 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_ULOG.c b/net/ipv4/netfilter/ipt_ULOG.c
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index 00000000000..6f2cefbe16c
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+++ b/net/ipv4/netfilter/ipt_ULOG.c
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+/*
+ * netfilter module for userspace packet logging daemons
+ *
+ * (C) 2000-2004 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>
+ * 2004/10/25 fix erroneous calculation of 'len' parameter to NLMSG_PUT
+ * resulting in bogus 'error during NLMSG_PUT' messages.
+ *
+ * (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 hundredths of a 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/moduleparam.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_param(nlbufsiz, uint, 0600); /* FIXME: Check size < 128k --RR */
+MODULE_PARM_DESC(nlbufsiz, "netlink buffer size");
+
+static unsigned int flushtimeout = 10;
+module_param(flushtimeout, int, 0600);
+MODULE_PARM_DESC(flushtimeout, "buffer flush timeout (hundredths of a second)");
+
+static unsigned int nflog = 1;
+module_param(nflog, int, 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 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, nlgroupnum);
+ 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 flushtimeout 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 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,
+ sizeof(*pm)+copy_len);
+ 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;
+ }
+
+ 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);
+ }
+
+ 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);