kernel-2.4: (tomj) updated ipt_ACCOUNT module
[ipt_ACCOUNT] / linux / net / ipv4 / netfilter / ipt_ACCOUNT.c
index ec65b30..a9286ee 100644 (file)
@@ -1,6 +1,17 @@
-/*
- * This is a module which is used for counting packets.
- */
+/***************************************************************************
+ *   This is a module which is used for counting packets.                  *
+ *   See http://www.intra2net.com/opensource/ipt_account                   *
+ *   for further information                                               *
+ *                                                                         * 
+ *   Copyright (C) 2004 by Intra2net AG                                    *
+ *   opensource@intra2net.com                                              *
+ *                                                                         *
+ *   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;               *
+ *                                                                         *
+ ***************************************************************************/
+
 #include <linux/module.h>
 #include <linux/skbuff.h>
 #include <linux/ip.h>
@@ -14,55 +25,45 @@ struct in_device;
 #include <net/route.h>
 #include <linux/netfilter_ipv4/ipt_ACCOUNT.h>
 
-//#if 0
+#if 0
 #define DEBUGP printk
-//#else
-//#define DEBUGP(format, args...)
-//#endif
+#else
+#define DEBUGP(format, args...)
+#endif
+
+#if (PAGE_SIZE < 4096)
+#error "ipt_ACCOUNT needs at least a PAGE_SIZE of 4096"
+#endif
 
 struct ipt_account_table *ipt_account_tables = NULL;
 struct ipt_account_handle *ipt_account_handles = NULL;
+void *ipt_account_tmpbuf = NULL;
 
+/* Spinlock used for manipulating the current accounting tables/data */
 static spinlock_t ipt_account_lock = SPIN_LOCK_UNLOCKED;
+/* Spinlock used for manipulating userspace handles/snapshot data */
+static spinlock_t ipt_account_userspace_lock = SPIN_LOCK_UNLOCKED;
 
-static unsigned int
-ipt_account_target(struct sk_buff **pskb,
-    unsigned int hooknum,
-    const struct net_device *in,
-    const struct net_device *out,
-    const void *targinfo,
-    void *userinfo)
-{
-    spin_lock_bh(&ipt_account_lock);
-    spin_unlock_bh(&ipt_account_lock);
-
-    return IPT_CONTINUE;
-}
 
 /* Recursive free of all data structures */
-void ipt_account_data_free(void *data, unsigned char depth)
-{
-    // Empty data set
+void ipt_account_data_free(void *data, unsigned char depth) {
+    /* Empty data set */
     if (!data)
         return;
-        
-    // Free for 8 bit network
-    if (depth == 0)
-    {
+
+    /* Free for 8 bit network */
+    if (depth == 0) {
         free_page((unsigned long)data);
         data = NULL;
         return;
     }
-    
-    // Free for 16 bit network
-    if (depth == 1)
-    {
+
+    /* Free for 16 bit network */
+    if (depth == 1) {
         struct ipt_account_mask_16 *mask_16 = (struct ipt_account_mask_16 *)data;
-        unsigned char b;
-        for (b=0; b < 255; b++)
-        {
-            if (mask_16->mask_24[b] != 0)
-            {
+        unsigned int b;
+        for (b=0; b <= 255; b++) {
+            if (mask_16->mask_24[b] != 0) {
                 free_page((unsigned long)mask_16->mask_24[b]);
                 mask_16->mask_24[b] = NULL;
             }
@@ -70,19 +71,15 @@ void ipt_account_data_free(void *data, unsigned char depth)
         free_page((unsigned long)data);
         data = NULL;
         return;
-    } 
-   
-    // Free for 24 bit network
-    if (depth == 3)
-    {
-        unsigned char a, b;
-        for (a=0; a < 255; a++)
-        {
-            if (((struct ipt_account_mask_8 *)data)->mask_16[a])
-            {
+    }
+
+    /* Free for 24 bit network */
+    if (depth == 3) {
+        unsigned int a, b;
+        for (a=0; a <= 255; a++) {
+            if (((struct ipt_account_mask_8 *)data)->mask_16[a]) {
                 struct ipt_account_mask_16 *mask_16 = (struct ipt_account_mask_16*)((struct ipt_account_mask_8 *)data)->mask_16[a];
-                for (b=0; b < 255; b++)
-                {
+                for (b=0; b <= 255; b++) {
                     if (mask_16->mask_24[b]) {
                         free_page((unsigned long)mask_16->mask_24[b]);
                         mask_16->mask_24[b] = NULL;
@@ -96,30 +93,26 @@ void ipt_account_data_free(void *data, unsigned char depth)
         data = NULL;
         return;
     }
-    
+
     printk("ACCOUNT: ipt_account_data_free called with unknown depth: %d\n", depth);
     return;
 }
 
 /* Look for existing table / insert new one. Return internal ID or -1 on error */
-int ipt_account_table_insert(char *name, unsigned int ip, unsigned int netmask)
-{
+int ipt_account_table_insert(char *name, unsigned int ip, unsigned int netmask) {
     unsigned int i;
 
     DEBUGP("ACCOUNT: ipt_account_table_insert: %s, %u.%u.%u.%u/%u.%u.%u.%u\n", name, NIPQUAD(ip), NIPQUAD(netmask));
 
-    // Look for existing table
-    for (i = 0; i < ACCOUNT_MAX_TABLES; i++)
-    {
-        if (strcmp(ipt_account_tables[i].name, name) == 0)
-        {
+    /* Look for existing table */
+    for (i = 0; i < ACCOUNT_MAX_TABLES; i++) {
+        if (strncmp(ipt_account_tables[i].name, name, ACCOUNT_TABLE_NAME_LEN) == 0) {
             DEBUGP("ACCOUNT: Found existing slot: %d - %u.%u.%u.%u/%u.%u.%u.%u\n", i,
                    NIPQUAD(ipt_account_tables[i].ip), NIPQUAD(ipt_account_tables[i].netmask));
-            
-            if (ipt_account_tables[i].ip != ip || ipt_account_tables[i].netmask != netmask)
-            {
+
+            if (ipt_account_tables[i].ip != ip || ipt_account_tables[i].netmask != netmask) {
                 printk("ACCOUNT: Table %s found, but IP/netmask mismatch. IP/netmask found: %u.%u.%u.%u/%u.%u.%u.%u\n",
-                        name, NIPQUAD(ipt_account_tables[i].ip), NIPQUAD(ipt_account_tables[i].netmask));
+                       name, NIPQUAD(ipt_account_tables[i].ip), NIPQUAD(ipt_account_tables[i].netmask));
                 return -1;
             }
 
@@ -129,168 +122,865 @@ int ipt_account_table_insert(char *name, unsigned int ip, unsigned int netmask)
         }
     }
 
-    // Insert new table
-    for (i = 0; i < ACCOUNT_MAX_TABLES; i++)
-    {
-        // Found free slot
-        if (ipt_account_tables[i].name[0] == 0)
-        {
+    /* Insert new table */
+    for (i = 0; i < ACCOUNT_MAX_TABLES; i++) {
+        /* Found free slot */
+        if (ipt_account_tables[i].name[0] == 0) {
             DEBUGP("ACCOUNT: Found free slot: %d\n", i);
-        
+
             strncpy (ipt_account_tables[i].name, name, ACCOUNT_TABLE_NAME_LEN-1);
-            
+
             ipt_account_tables[i].ip = ip;
             ipt_account_tables[i].netmask = netmask;
-            
-            // Calculate netsize
+
+            /* Calculate netsize */
             unsigned int j, calc_mask, netsize=0;
             calc_mask = htonl(netmask);
-            for (j = 31; j > 0; j--)
-            {
+            for (j = 31; j > 0; j--) {
                 if (calc_mask&(1<<j))
                     netsize++;
                 else
                     break;
             }
-            
-            // Calculate depth from netsize
+
+            /* Calculate depth from netsize */
             if (netsize >= 24)
                 ipt_account_tables[i].depth = 0;
             else if (netsize >= 16)
                 ipt_account_tables[i].depth = 1;
             else if(netsize >= 8)
                 ipt_account_tables[i].depth = 2;
-            
+
             printk("ACCOUNT: calculated netsize: %u -> ipt_account_table depth %u\n", netsize, ipt_account_tables[i].depth);
-                        
+
             ipt_account_tables[i].refcount++;
-            if (!(ipt_account_tables[i].data = (void *)get_zeroed_page(GFP_KERNEL)))
-            {
+            if ((ipt_account_tables[i].data = (void *)get_zeroed_page(GFP_ATOMIC)) == NULL) {
                 printk("ACCOUNT: out of memory for data of table: %s\n", name);
                 memset(&ipt_account_tables[i], 0, sizeof(struct ipt_account_table));
                 return -1;
             }
-            
+
             return i;
         }
     }
-        
-    // No free slot found
+
+    /* No free slot found */
     printk("ACCOUNT: No free table slot found (max: %d). Please increase ACCOUNT_MAX_TABLES.\n", ACCOUNT_MAX_TABLES);
     return -1;
 }
 
 static int ipt_account_checkentry(const char *tablename,
-    const struct ipt_entry *e,
-    void *targinfo,
-    unsigned int targinfosize,
-    unsigned int hook_mask)
-{
+                                  const struct ipt_entry *e,
+                                  void *targinfo,
+                                  unsigned int targinfosize,
+                                  unsigned int hook_mask) {
     struct ipt_account_info *info = targinfo;
-    
+
     if (targinfosize != IPT_ALIGN(sizeof(struct ipt_account_info))) {
         DEBUGP("ACCOUNT: targinfosize %u != %u\n",
-                targinfosize, IPT_ALIGN(sizeof(struct ipt_account_info)));
+               targinfosize, IPT_ALIGN(sizeof(struct ipt_account_info)));
         return 0;
     }
 
     spin_lock_bh(&ipt_account_lock);
     int table_nr = ipt_account_table_insert(info->table_name, info->net_ip, info->net_mask);
-    if (table_nr == -1)
-    {
+    if (table_nr == -1) {
         printk("ACCOUNT: Table insert problem. Aborting\n");
         spin_unlock_bh(&ipt_account_lock);
         return 0;
     }
-    // Table nr caching so we don't have to do an extra string compare for every packet
+    /* Table nr caching so we don't have to do an extra string compare for every packet */
     info->table_nr = table_nr;
-    
+
     spin_unlock_bh(&ipt_account_lock);
 
     return 1;
 }
 
-void ipt_account_deleteentry(void *targinfo, unsigned int targinfosize)
-{
+void ipt_account_deleteentry(void *targinfo, unsigned int targinfosize) {
     unsigned int i;
     struct ipt_account_info *info = targinfo;
-    
+
     if (targinfosize != IPT_ALIGN(sizeof(struct ipt_account_info))) {
         DEBUGP("ACCOUNT: targinfosize %u != %u\n",
-                targinfosize, IPT_ALIGN(sizeof(struct ipt_account_info)));
+               targinfosize, IPT_ALIGN(sizeof(struct ipt_account_info)));
     }
 
     spin_lock_bh(&ipt_account_lock);
-    
+
     DEBUGP("ACCOUNT: ipt_account_deleteentry called for table: %s (#%d)\n", info->table_name, info->table_nr);
-    
-    info->table_nr = -1;    // Set back to original state
-    
-    // Look for table
-    for (i = 0; i < ACCOUNT_MAX_TABLES; i++)
-    {
-        if (strcmp(ipt_account_tables[i].name, info->table_name) == 0)
-        {
+
+    info->table_nr = -1;    /* Set back to original state */
+
+    /* Look for table */
+    for (i = 0; i < ACCOUNT_MAX_TABLES; i++) {
+        if (strncmp(ipt_account_tables[i].name, info->table_name, ACCOUNT_TABLE_NAME_LEN) == 0) {
             DEBUGP("ACCOUNT: Found table at slot: %d\n", i);
-            
+
             ipt_account_tables[i].refcount--;
             DEBUGP("ACCOUNT: Refcount left: %d\n", ipt_account_tables[i].refcount);
 
-            // Table not needed anymore?
-            if (ipt_account_tables[i].refcount == 0)
-            {
+            /* Table not needed anymore? */
+            if (ipt_account_tables[i].refcount == 0) {
                 DEBUGP("ACCOUNT: Destroying table at slot: %d\n", i);
                 ipt_account_data_free(ipt_account_tables[i].data, ipt_account_tables[i].depth);
                 memset(&ipt_account_tables[i], 0, sizeof(struct ipt_account_table));
             }
-            
+
             spin_unlock_bh(&ipt_account_lock);
             return;
         }
     }
 
-    // Table not found
+    /* Table not found */
     printk("ACCOUNT: Table %s not found for destroy\n", info->table_name);
     spin_unlock_bh(&ipt_account_lock);
 }
 
-static struct ipt_target ipt_account_reg
-= { { NULL, NULL }, "ACCOUNT", ipt_account_target, ipt_account_checkentry, ipt_account_deleteentry, 
-    THIS_MODULE };
+void ipt_account_depth0_insert(struct ipt_account_mask_24 *mask_24, unsigned int net_ip, unsigned int netmask,
+                               unsigned int src_ip, unsigned int dst_ip, unsigned int size, unsigned int *itemcount) {
+    unsigned char is_src = 0, is_dst = 0;
+
+    DEBUGP("ACCOUNT: ipt_account_depth0_insert: %u.%u.%u.%u/%u.%u.%u.%u for net %u.%u.%u.%u/%u.%u.%u.%u, size: %u\n",
+           NIPQUAD(src_ip), NIPQUAD(dst_ip), NIPQUAD(net_ip), NIPQUAD(netmask), size);
+
+    /* Check if src/dst is inside our network. */
+    /* Special: net_ip = 0.0.0.0/0 gets stored as src in slot 0 */
+    if (!netmask)
+        src_ip = 0;
+    if ((net_ip&netmask) == (src_ip&netmask))
+        is_src = 1;
+    if ((net_ip&netmask) == (dst_ip&netmask) && netmask)
+        is_dst = 1;
+
+    if (!is_src && !is_dst) {
+        DEBUGP("ACCOUNT: Skipping packet %u.%u.%u.%u/%u.%u.%u.%u for net %u.%u.%u.%u/%u.%u.%u.%u\n",
+               NIPQUAD(src_ip), NIPQUAD(dst_ip), NIPQUAD(net_ip), NIPQUAD(netmask));
+        return;
+    }
+
+    /* Check if this entry is new */
+    char is_src_new_ip = 0, is_dst_new_ip = 0;
+
+    /* Calculate array positions */
+    unsigned char src_slot = (unsigned char)((src_ip&0xFF000000) >> 24);
+    unsigned char dst_slot = (unsigned char)((dst_ip&0xFF000000) >> 24);
+
+    /* Increase size counters */
+    if (is_src) {
+        /* Calculate network slot */
+        DEBUGP("ACCOUNT: Calculated SRC 8 bit network slot: %d\n", src_slot);
+        if (!mask_24->ip[src_slot].src_packets && !mask_24->ip[src_slot].dst_packets)
+            is_src_new_ip = 1;
+
+        mask_24->ip[src_slot].src_packets++;
+        mask_24->ip[src_slot].src_bytes+=size;
+    }
+    if (is_dst) {
+        DEBUGP("ACCOUNT: Calculated DST 8 bit network slot: %d\n", dst_slot);
+        if (!mask_24->ip[dst_slot].src_packets && !mask_24->ip[dst_slot].dst_packets)
+            is_dst_new_ip = 1;
+
+        mask_24->ip[dst_slot].dst_packets++;
+        mask_24->ip[dst_slot].dst_bytes+=size;
+    }
+
+    /* Increase itemcounter */
+    DEBUGP("ACCOUNT: Itemcounter before: %d\n", *itemcount);
+    if (src_slot == dst_slot) {
+        if (is_src_new_ip || is_dst_new_ip) {
+            DEBUGP("ACCOUNT: src_slot == dst_slot: %d, %d\n", is_src_new_ip, is_dst_new_ip);
+            (*itemcount)++;
+        }
+    } else {
+        if (is_src_new_ip) {
+            DEBUGP("ACCOUNT: New src_ip: %u.%u.%u.%u\n", NIPQUAD(src_ip));
+            (*itemcount)++;
+        }
+        if (is_dst_new_ip) {
+            DEBUGP("ACCOUNT: New dst_ip: %u.%u.%u.%u\n", NIPQUAD(dst_ip));
+            (*itemcount)++;
+        }
+    }
+    DEBUGP("ACCOUNT: Itemcounter after: %d\n", *itemcount);
+}
+
+void ipt_account_depth1_insert(struct ipt_account_mask_16 *mask_16, unsigned int net_ip, unsigned int netmask,
+                               unsigned int src_ip, unsigned int dst_ip, unsigned int size, unsigned int *itemcount) {
+    /* Do we need to process src IP? */
+    if ((net_ip&netmask) == (src_ip&netmask)) {
+        unsigned char slot = (unsigned char)((src_ip&0x00FF0000) >> 16);
+        DEBUGP("ACCOUNT: Calculated SRC 16 bit network slot: %d\n", slot);
+
+        /* Do we need to create a new mask_24 bucket? */
+        if (!mask_16->mask_24[slot] && (mask_16->mask_24[slot] = (void *)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+            printk("ACCOUNT: Can't process packet because out of memory!\n");
+            return;
+        }
+
+        ipt_account_depth0_insert((struct ipt_account_mask_24 *)mask_16->mask_24[slot], net_ip, netmask,
+                                  src_ip, 0, size, itemcount);
+    }
+
+    /* Do we need to process dst IP? */
+    if ((net_ip&netmask) == (dst_ip&netmask)) {
+        unsigned char slot = (unsigned char)((dst_ip&0x00FF0000) >> 16);
+        DEBUGP("ACCOUNT: Calculated DST 16 bit network slot: %d\n", slot);
+
+        /* Do we need to create a new mask_24 bucket? */
+        if (!mask_16->mask_24[slot] && (mask_16->mask_24[slot] = (void *)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+            printk("ACCOUT: Can't process packet because out of memory!\n");
+            return;
+        }
+
+        ipt_account_depth0_insert((struct ipt_account_mask_24 *)mask_16->mask_24[slot], net_ip, netmask,
+                                  0, dst_ip, size, itemcount);
+    }
+}
+
+void ipt_account_depth2_insert(struct ipt_account_mask_8 *mask_8, unsigned int net_ip, unsigned int netmask,
+                               unsigned int src_ip, unsigned int dst_ip, unsigned int size, unsigned int *itemcount) {
+    /* Do we need to process src IP? */
+    if ((net_ip&netmask) == (src_ip&netmask)) {
+        unsigned char slot = (unsigned char)((src_ip&0x0000FF00) >> 8);
+        DEBUGP("ACCOUNT: Calculated SRC 24 bit network slot: %d\n", slot);
+
+        /* Do we need to create a new mask_24 bucket? */
+        if (!mask_8->mask_16[slot] && (mask_8->mask_16[slot] = (void *)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+            printk("ACCOUNT: Can't process packet because out of memory!\n");
+            return;
+        }
+
+        ipt_account_depth1_insert((struct ipt_account_mask_16 *)mask_8->mask_16[slot], net_ip, netmask,
+                                  src_ip, 0, size, itemcount);
+    }
+
+    /* Do we need to process dst IP? */
+    if ((net_ip&netmask) == (dst_ip&netmask)) {
+        unsigned char slot = (unsigned char)((dst_ip&0x0000FF00) >> 8);
+        DEBUGP("ACCOUNT: Calculated DST 24 bit network slot: %d\n", slot);
+
+        /* Do we need to create a new mask_24 bucket? */
+        if (!mask_8->mask_16[slot] && (mask_8->mask_16[slot] = (void *)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+            printk("ACCOUNT: Can't process packet because out of memory!\n");
+            return;
+        }
+
+        ipt_account_depth1_insert((struct ipt_account_mask_16 *)mask_8->mask_16[slot], net_ip, netmask,
+                                  0, dst_ip, size, itemcount);
+    }
+}
+
+static unsigned int ipt_account_target(struct sk_buff **pskb,
+                                       unsigned int hooknum,
+                                       const struct net_device *in,
+                                       const struct net_device *out,
+                                       const void *targinfo,
+                                       void *userinfo) {
+    const struct ipt_account_info *info = (const struct ipt_account_info *)targinfo;
+    unsigned int src_ip = (*pskb)->nh.iph->saddr;
+    unsigned int dst_ip = (*pskb)->nh.iph->daddr;
+    unsigned int size = ntohs((*pskb)->nh.iph->tot_len);
+
+    spin_lock_bh(&ipt_account_lock);
+
+    if (ipt_account_tables[info->table_nr].name[0] == 0) {
+        printk("ACCOUNT: ipt_account_target: Invalid table id %u. IPs %u.%u.%u.%u/%u.%u.%u.%u\n",
+               info->table_nr, NIPQUAD(src_ip), NIPQUAD(dst_ip));
+        spin_unlock_bh(&ipt_account_lock);
+        return IPT_CONTINUE;
+    }
+
+    /* 8 bit network or "any" network */
+    if (ipt_account_tables[info->table_nr].depth == 0) {
+        /* Count packet and check if the IP is new */
+        ipt_account_depth0_insert((struct ipt_account_mask_24 *)ipt_account_tables[info->table_nr].data,
+                                  ipt_account_tables[info->table_nr].ip, ipt_account_tables[info->table_nr].netmask,
+                                  src_ip, dst_ip, size, &ipt_account_tables[info->table_nr].itemcount);
+        spin_unlock_bh(&ipt_account_lock);
+        return IPT_CONTINUE;
+    }
+
+    /* 16 bit network */
+    if (ipt_account_tables[info->table_nr].depth == 1) {
+        ipt_account_depth1_insert((struct ipt_account_mask_16 *)ipt_account_tables[info->table_nr].data,
+                                  ipt_account_tables[info->table_nr].ip, ipt_account_tables[info->table_nr].netmask,
+                                  src_ip, dst_ip, size, &ipt_account_tables[info->table_nr].itemcount);
+        spin_unlock_bh(&ipt_account_lock);
+        return IPT_CONTINUE;
+    }
+
+    /* 24 bit network */
+    if (ipt_account_tables[info->table_nr].depth == 2) {
+        ipt_account_depth2_insert((struct ipt_account_mask_8 *)ipt_account_tables[info->table_nr].data,
+                                  ipt_account_tables[info->table_nr].ip, ipt_account_tables[info->table_nr].netmask,
+                                  src_ip, dst_ip, size, &ipt_account_tables[info->table_nr].itemcount);
+        spin_unlock_bh(&ipt_account_lock);
+        return IPT_CONTINUE;
+    }
+
+    printk("ACCOUNT: ipt_account_target: Unable to process packet. Table id %u. IPs %u.%u.%u.%u/%u.%u.%u.%u\n",
+           info->table_nr, NIPQUAD(src_ip), NIPQUAD(dst_ip));
+
+    spin_unlock_bh(&ipt_account_lock);
+    return IPT_CONTINUE;
+}
+
+/*
+    Functions dealing with "handles":
+    Handles are snapshots of a accounting state.
+    
+    read snapshots are only for debugging the code
+    and are very expensive concerning speed/memory
+    compared to read_and_flush.
+    
+    The functions aren't protected by spinlocks themselves
+    as this is done in the ioctl part of the code.
+*/
+
+/*
+    Find a free handle slot. Normally only one should be used,
+    but there could be two or more applications accessing the data
+    at the same time.
+*/
+int ipt_account_handle_find_slot(void) {
+    unsigned int i;
+    /* Insert new table */
+    for (i = 0; i < ACCOUNT_MAX_HANDLES; i++) {
+        /* Found free slot */
+        if (ipt_account_handles[i].data == NULL) {
+            /* Don't "mark" data as used as we are protected by a spinlock by the calling function. */
+            /* handle_find_slot() is only a function to prevent code duplication. */
+            return i;
+        }
+    }
+
+    /* No free slot found */
+    printk("ACCOUNT: No free handle slot found (max: %u). Please increase ACCOUNT_MAX_HANDLES.\n", ACCOUNT_MAX_HANDLES);
+    return -1;
+}
+
+int ipt_account_handle_free(unsigned int handle) {
+    if (handle >= ACCOUNT_MAX_HANDLES) {
+        printk("ACCOUNT: Invalid handle for ipt_account_handle_free() specified: %u\n", handle);
+        return -EINVAL;
+    }
+
+    ipt_account_data_free(ipt_account_handles[handle].data, ipt_account_handles[handle].depth);
+    memset (&ipt_account_handles[handle], 0, sizeof (struct ipt_account_handle));
+    return 0;
+}
+
+/* Prepare data for read without flush. Use only for debugging!
+   Real applications should use read&flush as it's way more efficent */
+int ipt_account_handle_prepare_read(char *tablename, unsigned int *count) {
+    int handle, i, table_nr=-1;
+
+    for (i = 0; i < ACCOUNT_MAX_TABLES; i++)
+        if (strncmp(ipt_account_tables[i].name, tablename, ACCOUNT_TABLE_NAME_LEN) == 0) {
+            table_nr = i;
+            break;
+        }
+
+    if (table_nr == -1) {
+        printk("ACCOUNT: ipt_account_handle_prepare_read(): Table %s not found\n", tablename);
+        return -1;
+    }
+
+    /* Can't find a free handle slot? */
+    if ((handle = ipt_account_handle_find_slot()) == -1)
+        return -1;
+
+    /* Fill up handle structure */
+    ipt_account_handles[handle].ip = ipt_account_tables[table_nr].ip;
+    ipt_account_handles[handle].depth = ipt_account_tables[table_nr].depth;
+    ipt_account_handles[handle].itemcount = ipt_account_tables[table_nr].itemcount;
 
-static int __init init(void)
-{
-    if (!(ipt_account_tables = kmalloc(ACCOUNT_MAX_TABLES*sizeof(struct ipt_account_table), GFP_KERNEL)))
+    /* allocate "root" table */
+    if ((ipt_account_handles[handle].data = (void*)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+        printk("ACCOUNT: out of memory for root table in ipt_account_handle_prepare_read()\n");
+        memset (&ipt_account_handles[handle], 0, sizeof(struct ipt_account_handle));
+        return -1;
+    }
+
+    /* Recursive copy of complete data structure */
+    unsigned int depth = ipt_account_handles[handle].depth;
+    if (depth == 0) {
+        memcpy(ipt_account_handles[handle].data, ipt_account_tables[table_nr].data, sizeof(struct ipt_account_mask_24));
+    } else if (depth == 1) {
+        struct ipt_account_mask_16 *src_16 = (struct ipt_account_mask_16 *)ipt_account_tables[table_nr].data;
+        struct ipt_account_mask_16 *network_16 = (struct ipt_account_mask_16 *)ipt_account_handles[handle].data;
+        unsigned int b;
+
+        for (b = 0; b <= 255; b++) {
+            if (src_16->mask_24[b]) {
+                if ((network_16->mask_24[b] = (void*)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+                    printk("ACCOUNT: out of memory during copy of 16 bit network in ipt_account_handle_prepare_read()\n");
+                    ipt_account_data_free(ipt_account_handles[handle].data, depth);
+                    memset (&ipt_account_handles[handle], 0, sizeof(struct ipt_account_handle));
+                    return -1;
+                }
+
+                memcpy(network_16->mask_24[b], src_16->mask_24[b], sizeof(struct ipt_account_mask_24));
+            }
+        }
+    } else if(depth == 2) {
+        struct ipt_account_mask_8 *src_8 = (struct ipt_account_mask_8 *)ipt_account_tables[table_nr].data;
+        struct ipt_account_mask_8 *network_8 = (struct ipt_account_mask_8 *)ipt_account_handles[handle].data;
+        unsigned int a;
+
+        for (a = 0; a <= 255; a++) {
+            if (src_8->mask_16[a]) {
+                if ((network_8->mask_16[a] = (void*)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+                    printk("ACCOUNT: out of memory during copy of 24 bit network in ipt_account_handle_prepare_read()\n");
+                    ipt_account_data_free(ipt_account_handles[handle].data, depth);
+                    memset (&ipt_account_handles[handle], 0, sizeof(struct ipt_account_handle));
+                    return -1;
+                }
+
+                memcpy(network_8->mask_16[a], src_8->mask_16[a], sizeof(struct ipt_account_mask_16));
+
+                struct ipt_account_mask_16 *src_16 = src_8->mask_16[a];
+                struct ipt_account_mask_16 *network_16 = network_8->mask_16[a];
+                unsigned int b;
+
+                for (b = 0; b <= 255; b++) {
+                    if (src_16->mask_24[b]) {
+                        if ((network_16->mask_24[b] = (void*)get_zeroed_page(GFP_ATOMIC)) == NULL) {
+                            printk("ACCOUNT: out of memory during copy of 16 bit network in ipt_account_handle_prepare_read()\n");
+                            ipt_account_data_free(ipt_account_handles[handle].data, depth);
+                            memset (&ipt_account_handles[handle], 0, sizeof(struct ipt_account_handle));
+                            return -1;
+                        }
+
+                        memcpy(network_16->mask_24[b], src_16->mask_24[b], sizeof(struct ipt_account_mask_24));
+                    }
+                }
+            }
+        }
+    }
+
+    *count = ipt_account_tables[table_nr].itemcount;
+    return handle;
+}
+
+/* Prepare data for read and flush it */
+int ipt_account_handle_prepare_read_flush(char *tablename, unsigned int *count) {
+    int handle, i, table_nr=-1;
+
+    for (i = 0; i < ACCOUNT_MAX_TABLES; i++)
+        if (strncmp(ipt_account_tables[i].name, tablename, ACCOUNT_TABLE_NAME_LEN) == 0) {
+            table_nr = i;
+            break;
+        }
+
+    if (table_nr == -1) {
+        printk("ACCOUNT: ipt_account_handle_prepare_read_flush(): Table %s not found\n", tablename);
+        return -1;
+    }
+
+    /* Can't find a free handle slot? */
+    if ((handle = ipt_account_handle_find_slot()) == -1)
+        return -1;
+
+    /* Try to allocate memory */
+    void *new_data_page = (void*)get_zeroed_page(GFP_ATOMIC);
+    if (!new_data_page)
     {
-            printk("ACCOUNT: Out of memory allocating account_tables structure");
-            return -EINVAL;
+        printk("ACCOUNT: ipt_account_handle_prepare_read_flush(): Out of memory!\n");
+        return -1;
+    }
+
+    /* Fill up handle structure */
+    ipt_account_handles[handle].ip = ipt_account_tables[table_nr].ip;
+    ipt_account_handles[handle].depth = ipt_account_tables[table_nr].depth;
+    ipt_account_handles[handle].itemcount = ipt_account_tables[table_nr].itemcount;
+    ipt_account_handles[handle].data = ipt_account_tables[table_nr].data;
+    *count = ipt_account_tables[table_nr].itemcount;
+
+    /* "Flush" table data */
+    ipt_account_tables[table_nr].data = new_data_page;
+    ipt_account_tables[table_nr].itemcount = 0;
+
+    return handle;
+}
+
+/* Copy the actual that into a prepared buffer.
+   We only copy entries != 0 to increase performance.
+   The memory gets freed again in ipt_account_handle_free().
+*/
+int ipt_account_handle_get_data(unsigned int handle, void *buffer) {
+    struct ipt_account_handle_ip handle_ip;
+    unsigned int handle_ip_size = sizeof (struct ipt_account_handle_ip);
+    unsigned int i, tmpbuf_pos=0;
+
+    if (handle >= ACCOUNT_MAX_HANDLES) {
+        printk("ACCOUNT: invalid handle for ipt_account_handle_get_data() specified: %u\n", handle);
+        return -1;
+    }
+
+    if (ipt_account_handles[handle].data == NULL) {
+        printk("ACCOUNT: handle %u is BROKEN: Contains no data\n", handle);
+        return -1;
+    }
+
+    unsigned int net_ip = ipt_account_handles[handle].ip;
+    unsigned int depth = ipt_account_handles[handle].depth;
+
+    /* 8 bit network */
+    if (depth == 0) {
+        struct ipt_account_mask_24 *network = (struct ipt_account_mask_24*)ipt_account_handles[handle].data;
+        for (i = 0; i <= 255; i++) {
+            if (network->ip[i].src_packets || network->ip[i].dst_packets) {
+                handle_ip.ip = net_ip | (i<<24);
+                handle_ip.src_packets = network->ip[i].src_packets;
+                handle_ip.src_bytes = network->ip[i].src_bytes;
+                handle_ip.dst_packets = network->ip[i].dst_packets;
+                handle_ip.dst_bytes = network->ip[i].dst_bytes;
+
+                /* Temporary buffer full? Flush to userspace */
+                if (tmpbuf_pos+handle_ip_size >= PAGE_SIZE) {
+                    copy_to_user(buffer, ipt_account_tmpbuf, tmpbuf_pos);
+                    tmpbuf_pos = 0;
+                }
+                memcpy(ipt_account_tmpbuf+tmpbuf_pos, &handle_ip, handle_ip_size);
+                tmpbuf_pos += handle_ip_size;
+            }
+        }
+
+        /* Flush remaining data to userspace */
+        if (tmpbuf_pos)
+            copy_to_user(buffer, ipt_account_tmpbuf, tmpbuf_pos);
+
+        return 0;
+    }
+
+    /* 16 bit network */
+    if (depth == 1) {
+        struct ipt_account_mask_16 *network_16 = (struct ipt_account_mask_16*)ipt_account_handles[handle].data;
+        unsigned int b;
+        for (b = 0; b <= 255; b++) {
+            if (network_16->mask_24[b]) {
+                struct ipt_account_mask_24 *network = (struct ipt_account_mask_24*)network_16->mask_24[b];
+                for (i = 0; i <= 255; i++) {
+                    if (network->ip[i].src_packets || network->ip[i].dst_packets) {
+                        handle_ip.ip = net_ip | (b << 16) | (i<<24);
+                        handle_ip.src_packets = network->ip[i].src_packets;
+                        handle_ip.src_bytes = network->ip[i].src_bytes;
+                        handle_ip.dst_packets = network->ip[i].dst_packets;
+                        handle_ip.dst_bytes = network->ip[i].dst_bytes;
+
+                        /* Temporary buffer full? Flush to userspace */
+                        if (tmpbuf_pos+handle_ip_size >= PAGE_SIZE) {
+                            copy_to_user(buffer, ipt_account_tmpbuf, tmpbuf_pos);
+                            tmpbuf_pos = 0;
+                        }
+                        memcpy(ipt_account_tmpbuf+tmpbuf_pos, &handle_ip, handle_ip_size);
+                        tmpbuf_pos += handle_ip_size;
+                    }
+                }
+            }
+        }
+
+        /* Flush remaining data to userspace */
+        if (tmpbuf_pos)
+            copy_to_user(buffer, ipt_account_tmpbuf, tmpbuf_pos);
+
+        return 0;
+    }
+
+    /* 24 bit network */
+    if (depth == 2) {
+        struct ipt_account_mask_8 *network_8 = (struct ipt_account_mask_8*)ipt_account_handles[handle].data;
+        unsigned int a, b;
+        for (a = 0; a <= 255; a++) {
+            if (network_8->mask_16[a]) {
+                struct ipt_account_mask_16 *network_16 = (struct ipt_account_mask_16*)network_8->mask_16[a];
+                for (b = 0; b <= 255; b++) {
+                    if (network_16->mask_24[b]) {
+                        struct ipt_account_mask_24 *network = (struct ipt_account_mask_24*)network_16->mask_24[b];
+                        for (i = 0; i <= 255; i++) {
+                            if (network->ip[i].src_packets || network->ip[i].dst_packets) {
+                                handle_ip.ip = net_ip | (a << 8) | (b << 16) | (i<<24);
+                                handle_ip.src_packets = network->ip[i].src_packets;
+                                handle_ip.src_bytes = network->ip[i].src_bytes;
+                                handle_ip.dst_packets = network->ip[i].dst_packets;
+                                handle_ip.dst_bytes = network->ip[i].dst_bytes;
+
+                                /* Temporary buffer full? Flush to userspace */
+                                if (tmpbuf_pos+handle_ip_size >= PAGE_SIZE) {
+                                    copy_to_user(buffer, ipt_account_tmpbuf, tmpbuf_pos);
+                                    tmpbuf_pos = 0;
+                                }
+                                memcpy(ipt_account_tmpbuf+tmpbuf_pos, &handle_ip, handle_ip_size);
+                                tmpbuf_pos += handle_ip_size;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        /* Flush remaining data to userspace */
+        if (tmpbuf_pos)
+            copy_to_user(buffer, ipt_account_tmpbuf, tmpbuf_pos);
+
+        return 0;
+    }
+
+    return -1;
+}
+
+static int ipt_account_set_ctl(struct sock *sk, int cmd, void *user, unsigned int len) {
+    struct ipt_account_handle_sockopt handle;
+    int ret = -EINVAL;
+
+    if (!capable(CAP_NET_ADMIN))
+        return -EPERM;
+
+    switch (cmd) {
+    case IPT_SO_SET_ACCOUNT_HANDLE_FREE:
+        if (len != sizeof(struct ipt_account_handle_sockopt)) {
+            printk("ACCOUNT: ipt_account_set_ctl: wrong data size (%u != %u) for IPT_SO_SET_HANDLE_FREE\n", len, sizeof(struct ipt_account_handle_sockopt));
+            break;
+        }
+
+        if (copy_from_user (&handle, user, len)) {
+            printk("ACCOUNT: ipt_account_set_ctl: copy_from_user failed for IPT_SO_SET_HANDLE_FREE\n");
+            break;
+        }
+
+        spin_lock_bh(&ipt_account_userspace_lock);
+        ret = ipt_account_handle_free(handle.handle_nr);
+        spin_unlock_bh(&ipt_account_userspace_lock);
+        break;
+    case IPT_SO_SET_ACCOUNT_HANDLE_FREE_ALL: {
+            unsigned int i;
+            spin_lock_bh(&ipt_account_userspace_lock);
+            for (i = 0; i < ACCOUNT_MAX_HANDLES; i++)
+                ipt_account_handle_free(i);
+            spin_unlock_bh(&ipt_account_userspace_lock);
+            ret = 0;
+            break;
+        }
+    default:
+        printk("ACCOUNT: ipt_account_set_ctl: unknown request %i\n", cmd);
+    }
+
+    return ret;
+}
+
+static int ipt_account_get_ctl(struct sock *sk, int cmd, void *user, int *len) {
+    struct ipt_account_handle_sockopt handle;
+    int ret = -EINVAL;
+
+    if (!capable(CAP_NET_ADMIN))
+        return -EPERM;
+
+    switch (cmd) {
+    case IPT_SO_GET_ACCOUNT_PREPARE_READ_FLUSH:
+    case IPT_SO_GET_ACCOUNT_PREPARE_READ:
+        if (*len < sizeof(struct ipt_account_handle_sockopt)) {
+            printk("ACCOUNT: ipt_account_get_ctl: wrong data size (%u != %u) for IPT_SO_GET_ACCOUNT_PREPARE_READ/READ_FLUSH\n",
+                   *len, sizeof(struct ipt_account_handle_sockopt));
+            break;
+        }
+
+        if (copy_from_user (&handle, user, sizeof(struct ipt_account_handle_sockopt))) {
+            printk("ACCOUNT: ipt_account_get_ctl: copy_from_user failed for IPT_SO_GET_ACCOUNT_PREPARE_READ/READ_FLUSH\n");
+            break;
+        }
+
+        spin_lock_bh(&ipt_account_lock);
+        spin_lock_bh(&ipt_account_userspace_lock);
+        if (cmd == IPT_SO_GET_ACCOUNT_PREPARE_READ_FLUSH)
+            handle.handle_nr = ipt_account_handle_prepare_read_flush(handle.name, &handle.itemcount);
+        else
+            handle.handle_nr = ipt_account_handle_prepare_read(handle.name, &handle.itemcount);
+        spin_unlock_bh(&ipt_account_userspace_lock);
+        spin_unlock_bh(&ipt_account_lock);
+
+        if (handle.handle_nr == -1) {
+            printk("ACCOUNT: ipt_account_get_ctl: ipt_account_handle_prepare_read failed\n");
+            break;
+        }
+
+        if (copy_to_user(user, &handle, sizeof(struct ipt_account_handle_sockopt))) {
+            printk("ACCOUNT: ipt_account_set_ctl: copy_to_user failed for IPT_SO_GET_ACCOUNT_PREPARE_READ/READ_FLUSH\n");
+            break;
+        }
+        ret = 0;
+        break;
+    case IPT_SO_GET_ACCOUNT_GET_DATA:
+        if (*len < sizeof(struct ipt_account_handle_sockopt)) {
+            printk("ACCOUNT: ipt_account_get_ctl: wrong data size (%u != %u) for IPT_SO_GET_ACCOUNT_PREPARE_READ/READ_FLUSH\n",
+                   *len, sizeof(struct ipt_account_handle_sockopt));
+            break;
+        }
+
+        if (copy_from_user (&handle, user, sizeof(struct ipt_account_handle_sockopt))) {
+            printk("ACCOUNT: ipt_account_get_ctl: copy_from_user failed for IPT_SO_GET_ACCOUNT_PREPARE_READ/READ_FLUSH\n");
+            break;
+        }
+
+        if (handle.handle_nr >= ACCOUNT_MAX_HANDLES) {
+            printk("ACCOUNT: Invalid handle for IPT_SO_GET_ACCOUNT_GET_DATA: %u\n", handle.handle_nr);
+            break;
+        }
+
+        if (*len < ipt_account_handles[handle.handle_nr].itemcount*sizeof(struct ipt_account_handle_ip)) {
+            printk("ACCOUNT: ipt_account_get_ctl: not enough space (%u < %u) to store data from IPT_SO_GET_ACCOUNT_GET_DATA\n",
+                   *len, ipt_account_handles[handle.handle_nr].itemcount*sizeof(struct ipt_account_handle_ip));
+            ret = -ENOMEM;
+            break;
+        }
+
+        spin_lock_bh(&ipt_account_userspace_lock);
+        ret = ipt_account_handle_get_data(handle.handle_nr, user);
+        spin_unlock_bh(&ipt_account_userspace_lock);
+        if (ret) {
+            printk("ACCOUNT: ipt_account_get_ctl: ipt_account_handle_get_data failed for handle %u\n", handle.handle_nr);
+            break;
+        }
+
+        ret = 0;
+        break;
+    case IPT_SO_GET_ACCOUNT_GET_HANDLE_USAGE: {
+            if (*len < sizeof(struct ipt_account_handle_sockopt)) {
+                printk("ACCOUNT: ipt_account_get_ctl: wrong data size (%u != %u) for IPT_SO_GET_ACCOUNT_GET_HANDLE_USAGE\n",
+                       *len, sizeof(struct ipt_account_handle_sockopt));
+                break;
+            }
+
+            /* Find out how many handles are in use */
+            unsigned int i;
+            handle.itemcount = 0;
+            spin_lock_bh(&ipt_account_userspace_lock);
+            for (i = 0; i < ACCOUNT_MAX_HANDLES; i++)
+                if (ipt_account_handles[i].data)
+                    handle.itemcount++;
+            spin_unlock_bh(&ipt_account_userspace_lock);
+
+            if (copy_to_user(user, &handle, sizeof(struct ipt_account_handle_sockopt))) {
+                printk("ACCOUNT: ipt_account_set_ctl: copy_to_user failed for IPT_SO_GET_ACCOUNT_GET_HANDLE_USAGE\n");
+                break;
+            }
+            ret = 0;
+            break;
+        }
+    case IPT_SO_GET_ACCOUNT_GET_TABLE_NAMES: {
+            spin_lock_bh(&ipt_account_lock);
+
+            /* Determine size of table names */
+            unsigned int size = 0, i;
+            for (i = 0; i < ACCOUNT_MAX_TABLES; i++) {
+                if (ipt_account_tables[i].name[0] != 0)
+                    size += strlen (ipt_account_tables[i].name) + 1;
+            }
+            size += 1;    /* Terminating NULL character */
+
+            if (*len < size) {
+                spin_unlock_bh(&ipt_account_lock);
+                printk("ACCOUNT: ipt_account_get_ctl: not enough space (%u < %u) to store table names\n", *len, size);
+                ret = -ENOMEM;
+                break;
+            }
+            /* Copy table names to userspace */
+            char *tnames = user;
+            for (i = 0; i < ACCOUNT_MAX_TABLES; i++) {
+                if (ipt_account_tables[i].name[0] != 0) {
+                    int len = strlen (ipt_account_tables[i].name) + 1;
+                    copy_to_user(tnames, ipt_account_tables[i].name, len);    /* copy string + terminating zero */
+                    tnames += len;
+                }
+            }
+            /* Append terminating zero */
+            i = 0;
+            copy_to_user(tnames, &i, 1);
+            spin_unlock_bh(&ipt_account_lock);
+            ret = 0;
+            break;
+        }
+    default:
+        printk("ACCOUNT: ipt_account_get_ctl: unknown request %i\n", cmd);
+    }
+
+    return ret;
+}
+
+static struct ipt_target ipt_account_reg
+    = { {
+          NULL, NULL
+      }
+      , "ACCOUNT", ipt_account_target, ipt_account_checkentry, ipt_account_deleteentry,
+      THIS_MODULE
+  };
+
+static struct nf_sockopt_ops ipt_account_sockopts
+    = { {
+          NULL, NULL
+      }
+      , PF_INET, IPT_SO_SET_ACCOUNT_HANDLE_FREE, IPT_SO_SET_ACCOUNT_MAX+1, ipt_account_set_ctl,
+      IPT_SO_GET_ACCOUNT_PREPARE_READ, IPT_SO_GET_ACCOUNT_MAX+1, ipt_account_get_ctl, 0, NULL
+  };
+
+static int __init init(void) {
+    if ((ipt_account_tables = kmalloc(ACCOUNT_MAX_TABLES*sizeof(struct ipt_account_table), GFP_KERNEL)) == NULL) {
+        printk("ACCOUNT: Out of memory allocating account_tables structure");
+        return -EINVAL;
     }
     memset(ipt_account_tables, 0, ACCOUNT_MAX_TABLES*sizeof(struct ipt_account_table));
-                            
-    if (!(ipt_account_handles = kmalloc(ACCOUNT_MAX_HANDLES*sizeof(struct ipt_account_handle), GFP_KERNEL)))
-    {
-            printk("ACCOUNT: Out of memory allocating account_handles structure");
-            kfree (ipt_account_tables);
-            ipt_account_tables = NULL;
-            return -EINVAL;
+
+    if ((ipt_account_handles = kmalloc(ACCOUNT_MAX_HANDLES*sizeof(struct ipt_account_handle), GFP_KERNEL)) == NULL) {
+        printk("ACCOUNT: Out of memory allocating account_handles structure");
+        kfree (ipt_account_tables);
+        ipt_account_tables = NULL;
+        return -EINVAL;
     }
     memset(ipt_account_handles, 0, ACCOUNT_MAX_HANDLES*sizeof(struct ipt_account_handle));
-    
+
+    /* Allocate one page as temporary storage */
+    if ((ipt_account_tmpbuf = (void*)__get_free_page(GFP_KERNEL)) == NULL) {
+        printk("ACCOUNT: Out of memory for temporary buffer page\n");
+        kfree(ipt_account_tables);
+        kfree(ipt_account_handles);
+        ipt_account_tables = NULL;
+        ipt_account_handles = NULL;
+        return -EINVAL;
+    }
+
+    /* Register setsockopt */
+    if (nf_register_sockopt(&ipt_account_sockopts) < 0) {
+        printk("ACCOUNT: Can't register sockopts. Aborting\n");
+
+        kfree(ipt_account_tables);
+        kfree(ipt_account_handles);
+        free_page((unsigned long)ipt_account_tmpbuf);
+        ipt_account_tables = NULL;
+        ipt_account_handles = NULL;
+        ipt_account_tmpbuf = NULL;
+
+        return -EINVAL;
+    }
+
     if (ipt_register_target(&ipt_account_reg))
-            return -EINVAL;
+        return -EINVAL;
 
     return 0;
 }
 
-static void __exit fini(void)
-{
+static void __exit fini(void) {
     ipt_unregister_target(&ipt_account_reg);
 
+    nf_unregister_sockopt(&ipt_account_sockopts);
+
     kfree(ipt_account_tables);
-    ipt_account_tables = NULL;
-        
     kfree(ipt_account_handles);
+    free_page((unsigned long)ipt_account_tmpbuf);
+
+    ipt_account_tables = NULL;
     ipt_account_handles = NULL;
+    ipt_account_tmpbuf = NULL;
 }
 
 module_init(init);