--- /dev/null
+/*
+ * netfilter module for userspace bridged Ethernet frames logging daemons
+ *
+ * Authors:
+ * Bart De Schuymer <bdschuym@pandora.be>
+ *
+ * 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.
+ *
+ */
+
+#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/module.h>
+#include <linux/netfilter_bridge/ebtables.h>
+#include <linux/netfilter_bridge/ebt_ulog.h>
+#include <net/sock.h>
+#include "../br_private.h"
+
+#define PRINTR(format, args...) do { if (net_ratelimit()) \
+ printk(format , ## args); } while (0)
+
+static unsigned int nlbufsiz = 4096;
+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);
+
+ /* last nlmsg needs NLMSG_DONE */
+ if (ub->qlen > 1)
+ ub->lastnlh->nlmsg_type = NLMSG_DONE;
+
+ NETLINK_CB(ub->skb).dst_groups = 1 << nlgroup;
+ netlink_broadcast(ebtulognl, ub->skb, 0, 1 << nlgroup, 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;
+
+ skb = alloc_skb(nlbufsiz, GFP_ATOMIC);
+ if (!skb) {
+ PRINTR(KERN_ERR "ebt_ulog: can't alloc whole buffer "
+ "of size %ub!\n", nlbufsiz);
+ if (size < nlbufsiz) {
+ /* try to allocate only as much as we need for
+ * current packet */
+ skb = alloc_skb(size, GFP_ATOMIC);
+ if (!skb)
+ PRINTR(KERN_ERR "ebt_ulog: can't even allocate "
+ "buffer of size %ub\n", size);
+ }
+ }
+
+ return skb;
+}
+
+static void ebt_ulog(const struct sk_buff *skb, unsigned int hooknr,
+ const struct net_device *in, const struct net_device *out,
+ const void *data, unsigned int datalen)
+{
+ ebt_ulog_packet_msg_t *pm;
+ size_t size, copy_len;
+ struct nlmsghdr *nlh;
+ struct ebt_ulog_info *uloginfo = (struct ebt_ulog_info *)data;
+ unsigned int group = uloginfo->nlgroup;
+ ebt_ulog_buff_t *ub = &ulog_buffers[group];
+ spinlock_t *lock = &ub->lock;
+
+ 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) {
+ PRINTR("ebt_ulog: 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;
+ do_gettimeofday(&pm->stamp);
+ if (ub->qlen == 1)
+ ub->skb->stamp = pm->stamp;
+ pm->data_len = copy_len;
+ pm->mark = skb->nfmark;
+ 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 (in->br_port)
+ strcpy(pm->indev, in->br_port->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);
+ strcpy(pm->outdev, out->br_port->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:
+ printk(KERN_CRIT "ebt_ulog: error during NLMSG_PUT. This should "
+ "not happen, please report to author.\n");
+ goto unlock;
+alloc_failure:
+ goto unlock;
+}
+
+static int ebt_ulog_check(const char *tablename, unsigned int hookmask,
+ const struct ebt_entry *e, void *data, unsigned int datalen)
+{
+ struct ebt_ulog_info *uloginfo = (struct ebt_ulog_info *)data;
+
+ if (datalen != EBT_ALIGN(sizeof(struct ebt_ulog_info)) ||
+ 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 ebt_watcher ulog = {
+ .name = EBT_ULOG_WATCHER,
+ .watcher = ebt_ulog,
+ .check = ebt_ulog_check,
+ .me = THIS_MODULE,
+};
+
+static int __init init(void)
+{
+ int i, ret = 0;
+
+ if (nlbufsiz >= 128*1024) {
+ printk(KERN_NOTICE "ebt_ulog: 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++) {
+ init_timer(&ulog_buffers[i].timer);
+ ulog_buffers[i].timer.function = ulog_timer;
+ ulog_buffers[i].timer.data = i;
+ spin_lock_init(&ulog_buffers[i].lock);
+ }
+
+ ebtulognl = netlink_kernel_create(NETLINK_NFLOG, NULL);
+ if (!ebtulognl)
+ ret = -ENOMEM;
+ else if ((ret = ebt_register_watcher(&ulog)))
+ sock_release(ebtulognl->sk_socket);
+
+ return ret;
+}
+
+static void __exit fini(void)
+{
+ ebt_ulog_buff_t *ub;
+ int i;
+
+ ebt_unregister_watcher(&ulog);
+ 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);
+ }
+ sock_release(ebtulognl->sk_socket);
+}
+
+module_init(init);
+module_exit(fini);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
+MODULE_DESCRIPTION("ebtables userspace logging module for bridged Ethernet"
+ " frames");
git://git.onelab.eu / linux-2.6.git / blobdiff