/* Kernel module to check if the source address has been seen recently. */
/* Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org */
/* Author: Stephen Frost <sfrost@snowman.net> */
/* Project Page: http://snowman.net/projects/ipt_recent/ */
/* This software is distributed under the terms of the GPL, Version 2 */
/* This copyright does not cover user programs that use kernel services
* by normal system calls. */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <linux/ctype.h>
#include <linux/ip.h>
#include <linux/vmalloc.h>
#include <linux/moduleparam.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_recent.h>
#undef DEBUG
#define HASH_LOG 9
/* Defaults, these can be overridden on the module command-line. */
static int ip_list_tot = 100;
static int ip_pkt_list_tot = 20;
static int ip_list_hash_size = 0;
static int ip_list_perms = 0644;
#ifdef DEBUG
static int debug = 1;
#endif
static char version[] =
KERN_INFO RECENT_NAME " " RECENT_VER ": Stephen Frost <sfrost@snowman.net>. http://snowman.net/projects/ipt_recent/\n";
MODULE_AUTHOR("Stephen Frost <sfrost@snowman.net>");
MODULE_DESCRIPTION("IP tables recently seen matching module " RECENT_VER);
MODULE_LICENSE("GPL");
module_param(ip_list_tot, int, 0400);
module_param(ip_pkt_list_tot, int, 0400);
module_param(ip_list_hash_size, int, 0400);
module_param(ip_list_perms, int, 0400);
#ifdef DEBUG
module_param(debug, int, 0600);
MODULE_PARM_DESC(debug,"debugging level, defaults to 1");
#endif
MODULE_PARM_DESC(ip_list_tot,"number of IPs to remember per list");
MODULE_PARM_DESC(ip_pkt_list_tot,"number of packets per IP to remember");
MODULE_PARM_DESC(ip_list_hash_size,"size of hash table used to look up IPs");
MODULE_PARM_DESC(ip_list_perms,"permissions on /proc/net/ipt_recent/* files");
/* Structure of our list of recently seen addresses. */
struct recent_ip_list {
u_int32_t addr;
u_int8_t ttl;
unsigned long last_seen;
unsigned long *last_pkts;
u_int32_t oldest_pkt;
u_int32_t hash_entry;
u_int32_t time_pos;
};
struct time_info_list {
u_int32_t position;
u_int32_t time;
};
/* Structure of our linked list of tables of recent lists. */
struct recent_ip_tables {
char name[IPT_RECENT_NAME_LEN];
int count;
int time_pos;
struct recent_ip_list *table;
struct recent_ip_tables *next;
spinlock_t list_lock;
int *hash_table;
struct time_info_list *time_info;
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *status_proc;
#endif /* CONFIG_PROC_FS */
};
/* Our current list of addresses we have recently seen.
* Only added to on a --set, and only updated on --set || --update
*/
static struct recent_ip_tables *r_tables = NULL;
/* We protect r_list with this spinlock so two processors are not modifying
* the list at the same time.
*/
static DEFINE_SPINLOCK(recent_lock);
#ifdef CONFIG_PROC_FS
/* Our /proc/net/ipt_recent entry */
static struct proc_dir_entry *proc_net_ipt_recent = NULL;
#endif
/* Function declaration for later. */
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
int *hotdrop);
/* Function to hash a given address into the hash table of table_size size */
static int hash_func(unsigned int addr, int table_size)
{
int result = 0;
unsigned int value = addr;
do { result ^= value; } while((value >>= HASH_LOG));
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": %d = hash_func(%u,%d)\n",
result & (table_size - 1),
addr,
table_size);
#endif
return(result & (table_size - 1));
}
#ifdef CONFIG_PROC_FS
/* This is the function which produces the output for our /proc output
* interface which lists each IP address, the last seen time and the
* other recent times the address was seen.
*/
static int ip_recent_get_info(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
{
int len = 0, count, last_len = 0, pkt_count;
off_t pos = 0;
off_t begin = 0;
struct recent_ip_tables *curr_table;
curr_table = (struct recent_ip_tables*) data;
spin_lock_bh(&curr_table->list_lock);
for(count = 0; count < ip_list_tot; count++) {
if(!curr_table->table[count].addr) continue;
last_len = len;
len += sprintf(buffer+len,"src=%u.%u.%u.%u ",NIPQUAD(curr_table->table[count].addr));
len += sprintf(buffer+len,"ttl: %u ",curr_table->table[count].ttl);
len += sprintf(buffer+len,"last_seen: %lu ",curr_table->table[count].last_seen);
len += sprintf(buffer+len,"oldest_pkt: %u ",curr_table->table[count].oldest_pkt);
len += sprintf(buffer+len,"last_pkts: %lu",curr_table->table[count].last_pkts[0]);
for(pkt_count = 1; pkt_count < ip_pkt_list_tot; pkt_count++) {
if(!curr_table->table[count].last_pkts[pkt_count]) break;
len += sprintf(buffer+len,", %lu",curr_table->table[count].last_pkts[pkt_count]);
}
len += sprintf(buffer+len,"\n");
pos = begin + len;
if(pos < offset) { len = 0; begin = pos; }
if(pos > offset + length) { len = last_len; break; }
}
*start = buffer + (offset - begin);
len -= (offset - begin);
if(len > length) len = length;
spin_unlock_bh(&curr_table->list_lock);
return len;
}
/* ip_recent_ctrl provides an interface for users to modify the table
* directly. This allows adding entries, removing entries, and
* flushing the entire table.
* This is done by opening up the appropriate table for writing and
* sending one of:
* xx.xx.xx.xx -- Add entry to table with current time
* +xx.xx.xx.xx -- Add entry to table with current time
* -xx.xx.xx.xx -- Remove entry from table
* clear -- Flush table, remove all entries
*/
static int ip_recent_ctrl(struct file *file, const char __user *input, unsigned long size, void *data)
{
static const u_int32_t max[4] = { 0xffffffff, 0xffffff, 0xffff, 0xff };
u_int32_t val;
int base, used = 0;
char c, *cp;
union iaddr {
uint8_t bytes[4];
uint32_t word;
} res;
uint8_t *pp = res.bytes;
int digit;
char buffer[20];
int len, check_set = 0, count;
u_int32_t addr = 0;
struct sk_buff *skb;
struct ipt_recent_info *info;
struct recent_ip_tables *curr_table;
curr_table = (struct recent_ip_tables*) data;
if(size > 20) len = 20; else len = size;
if(copy_from_user(buffer,input,len)) return -EFAULT;
if(len < 20) buffer[len] = '\0';
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": ip_recent_ctrl len: %d, input: `%.20s'\n",len,buffer);
#endif
cp = buffer;
while(isspace(*cp)) { cp++; used++; if(used >= len-5) return used; }
/* Check if we are asked to flush the entire table */
if(!memcmp(cp,"clear",5)) {
used += 5;
spin_lock_bh(&curr_table->list_lock);
curr_table->time_pos = 0;
for(count = 0; count < ip_list_hash_size; count++) {
curr_table->hash_table[count] = -1;
}
for(count = 0; count < ip_list_tot; count++) {
curr_table->table[count].last_seen = 0;
curr_table->table[count].addr = 0;
curr_table->table[count].ttl = 0;
memset(curr_table->table[count].last_pkts,0,ip_pkt_list_tot*sizeof(unsigned long));
curr_table->table[count].oldest_pkt = 0;
curr_table->table[count].time_pos = 0;
curr_table->time_info[count].position = count;
curr_table->time_info[count].time = 0;
}
spin_unlock_bh(&curr_table->list_lock);
return used;
}
check_set = IPT_RECENT_SET;
switch(*cp) {
case '+': check_set = IPT_RECENT_SET; cp++; used++; break;
case '-': check_set = IPT_RECENT_REMOVE; cp++; used++; break;
default: if(!isdigit(*cp)) return (used+1); break;
}
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": ip_recent_ctrl cp: `%c', check_set: %d\n",*cp,check_set);
#endif
/* Get addr (effectively inet_aton()) */
/* Shamelessly stolen from libc, a function in the kernel for doing
* this would, of course, be greatly preferred, but our options appear
* to be rather limited, so we will just do it ourselves here.
*/
res.word = 0;
c = *cp;
for(;;) {
if(!isdigit(c)) return used;
val = 0; base = 10; digit = 0;
if(c == '0') {
c = *++cp;
if(c == 'x' || c == 'X') base = 16, c = *++cp;
else { base = 8; digit = 1; }
}
for(;;) {
if(isascii(c) && isdigit(c)) {
if(base == 8 && (c == '8' || c == '0')) return used;
val = (val * base) + (c - '0');
c = *++cp;
digit = 1;
} else if(base == 16 && isascii(c) && isxdigit(c)) {
val = (val << 4) | (c + 10 - (islower(c) ? 'a' : 'A'));
c = *++cp;
digit = 1;
} else break;
}
if(c == '.') {
if(pp > res.bytes + 2 || val > 0xff) return used;
*pp++ = val;
c = *++cp;
} else break;
}
used = cp - buffer;
if(c != '\0' && (!isascii(c) || !isspace(c))) return used;
if(c == '\n') used++;
if(!digit) return used;
if(val > max[pp - res.bytes]) return used;
addr = res.word | htonl(val);
if(!addr && check_set == IPT_RECENT_SET) return used;
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": ip_recent_ctrl c: %c, addr: %u used: %d\n",c,addr,used);
#endif
/* Set up and just call match */
info = kmalloc(sizeof(struct ipt_recent_info),GFP_KERNEL);
if(!info) { return -ENOMEM; }
info->seconds = 0;
info->hit_count = 0;
info->check_set = check_set;
info->invert = 0;
info->side = IPT_RECENT_SOURCE;
strncpy(info->name,curr_table->name,IPT_RECENT_NAME_LEN);
info->name[IPT_RECENT_NAME_LEN-1] = '\0';
skb = kmalloc(sizeof(struct sk_buff),GFP_KERNEL);
if (!skb) {
used = -ENOMEM;
goto out_free_info;
}
skb->nh.iph = kmalloc(sizeof(struct iphdr),GFP_KERNEL);
if (!skb->nh.iph) {
used = -ENOMEM;
goto out_free_skb;
}
skb->nh.iph->saddr = addr;
skb->nh.iph->daddr = 0;
/* Clear ttl since we have no way of knowing it */
skb->nh.iph->ttl = 0;
match(skb,NULL,NULL,info,0,NULL);
kfree(skb->nh.iph);
out_free_skb:
kfree(skb);
out_free_info:
kfree(info);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": Leaving ip_recent_ctrl addr: %u used: %d\n",addr,used);
#endif
return used;
}
#endif /* CONFIG_PROC_FS */
/* 'match' is our primary function, called by the kernel whenever a rule is
* hit with our module as an option to it.
* What this function does depends on what was specifically asked of it by
* the user:
* --set -- Add or update last seen time of the source address of the packet
* -- matchinfo->check_set == IPT_RECENT_SET
* --rcheck -- Just check if the source address is in the list
* -- matchinfo->check_set == IPT_RECENT_CHECK
* --update -- If the source address is in the list, update last_seen
* -- matchinfo->check_set == IPT_RECENT_UPDATE
* --remove -- If the source address is in the list, remove it
* -- matchinfo->check_set == IPT_RECENT_REMOVE
* --seconds -- Option to --rcheck/--update, only match if last_seen within seconds
* -- matchinfo->seconds
* --hitcount -- Option to --rcheck/--update, only match if seen hitcount times
* -- matchinfo->hit_count
* --seconds and --hitcount can be combined
*/
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset,
int *hotdrop)
{
int pkt_count, hits_found, ans;
unsigned long now;
const struct ipt_recent_info *info = matchinfo;
u_int32_t addr = 0, time_temp;
u_int8_t ttl = skb->nh.iph->ttl;
int *hash_table;
int orig_hash_result, hash_result, temp, location = 0, time_loc, end_collision_chain = -1;
struct time_info_list *time_info;
struct recent_ip_tables *curr_table;
struct recent_ip_tables *last_table;
struct recent_ip_list *r_list;
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match() called\n");
#endif
/* Default is false ^ info->invert */
ans = info->invert;
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): name = '%s'\n",info->name);
#endif
/* if out != NULL then routing has been done and TTL changed.
* We change it back here internally for match what came in before routing. */
if(out) ttl++;
/* Find the right table */
spin_lock_bh(&recent_lock);
curr_table = r_tables;
while( (last_table = curr_table) && strncmp(info->name,curr_table->name,IPT_RECENT_NAME_LEN) && (curr_table = curr_table->next) );
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): table found('%s')\n",info->name);
#endif
spin_unlock_bh(&recent_lock);
/* Table with this name not found, match impossible */
if(!curr_table) { return ans; }
/* Make sure no one is changing the list while we work with it */
spin_lock_bh(&curr_table->list_lock);
r_list = curr_table->table;
if(info->side == IPT_RECENT_DEST) addr = skb->nh.iph->daddr; else addr = skb->nh.iph->saddr;
if(!addr) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match() address (%u) invalid, leaving.\n",addr);
#endif
spin_unlock_bh(&curr_table->list_lock);
return ans;
}
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): checking table, addr: %u, ttl: %u, orig_ttl: %u\n",addr,ttl,skb->nh.iph->ttl);
#endif
/* Get jiffies now in case they changed while we were waiting for a lock */
now = jiffies;
hash_table = curr_table->hash_table;
time_info = curr_table->time_info;
orig_hash_result = hash_result = hash_func(addr,ip_list_hash_size);
/* Hash entry at this result used */
/* Check for TTL match if requested. If TTL is zero then a match would never
* happen, so match regardless of existing TTL in that case. Zero means the
* entry was added via the /proc interface anyway, so we will just use the
* first TTL we get for that IP address. */
if(info->check_set & IPT_RECENT_TTL) {
while(hash_table[hash_result] != -1 && !(r_list[hash_table[hash_result]].addr == addr &&
(!r_list[hash_table[hash_result]].ttl || r_list[hash_table[hash_result]].ttl == ttl))) {
/* Collision in hash table */
hash_result = (hash_result + 1) % ip_list_hash_size;
}
} else {
while(hash_table[hash_result] != -1 && r_list[hash_table[hash_result]].addr != addr) {
/* Collision in hash table */
hash_result = (hash_result + 1) % ip_list_hash_size;
}
}
if(hash_table[hash_result] == -1 && !(info->check_set & IPT_RECENT_SET)) {
/* IP not in list and not asked to SET */
spin_unlock_bh(&curr_table->list_lock);
return ans;
}
/* Check if we need to handle the collision, do not need to on REMOVE */
if(orig_hash_result != hash_result && !(info->check_set & IPT_RECENT_REMOVE)) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): Collision in hash table. (or: %d,hr: %d,oa: %u,ha: %u)\n",
orig_hash_result,
hash_result,
r_list[hash_table[orig_hash_result]].addr,
addr);
#endif
/* We had a collision.
* orig_hash_result is where we started, hash_result is where we ended up.
* So, swap them because we are likely to see the same guy again sooner */
#ifdef DEBUG
if(debug) {
printk(KERN_INFO RECENT_NAME ": match(): Collision; hash_table[orig_hash_result] = %d\n",hash_table[orig_hash_result]);
printk(KERN_INFO RECENT_NAME ": match(): Collision; r_list[hash_table[orig_hash_result]].hash_entry = %d\n",
r_list[hash_table[orig_hash_result]].hash_entry);
}
#endif
r_list[hash_table[orig_hash_result]].hash_entry = hash_result;
temp = hash_table[orig_hash_result];
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): Collision; hash_table[hash_result] = %d\n",hash_table[hash_result]);
#endif
hash_table[orig_hash_result] = hash_table[hash_result];
hash_table[hash_result] = temp;
temp = hash_result;
hash_result = orig_hash_result;
orig_hash_result = temp;
time_info[r_list[hash_table[orig_hash_result]].time_pos].position = hash_table[orig_hash_result];
if(hash_table[hash_result] != -1) {
r_list[hash_table[hash_result]].hash_entry = hash_result;
time_info[r_list[hash_table[hash_result]].time_pos].position = hash_table[hash_result];
}
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): Collision handled.\n");
#endif
}
if(hash_table[hash_result] == -1) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): New table entry. (hr: %d,ha: %u)\n",
hash_result, addr);
#endif
/* New item found and IPT_RECENT_SET, so we need to add it */
location = time_info[curr_table->time_pos].position;
hash_table[r_list[location].hash_entry] = -1;
hash_table[hash_result] = location;
memset(r_list[location].last_pkts,0,ip_pkt_list_tot*sizeof(unsigned long));
r_list[location].time_pos = curr_table->time_pos;
r_list[location].addr = addr;
r_list[location].ttl = ttl;
r_list[location].last_seen = now;
r_list[location].oldest_pkt = 1;
r_list[location].last_pkts[0] = now;
r_list[location].hash_entry = hash_result;
time_info[curr_table->time_pos].time = r_list[location].last_seen;
curr_table->time_pos = (curr_table->time_pos + 1) % ip_list_tot;
ans = !info->invert;
} else {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): Existing table entry. (hr: %d,ha: %u)\n",
hash_result,
addr);
#endif
/* Existing item found */
location = hash_table[hash_result];
/* We have a match on address, now to make sure it meets all requirements for a
* full match. */
if(info->check_set & IPT_RECENT_CHECK || info->check_set & IPT_RECENT_UPDATE) {
if(!info->seconds && !info->hit_count) ans = !info->invert; else ans = info->invert;
if(info->seconds && !info->hit_count) {
if(time_before_eq(now,r_list[location].last_seen+info->seconds*HZ)) ans = !info->invert; else ans = info->invert;
}
if(info->seconds && info->hit_count) {
for(pkt_count = 0, hits_found = 0; pkt_count < ip_pkt_list_tot; pkt_count++) {
if(r_list[location].last_pkts[pkt_count] == 0) break;
if(time_before_eq(now,r_list[location].last_pkts[pkt_count]+info->seconds*HZ)) hits_found++;
}
if(hits_found >= info->hit_count) ans = !info->invert; else ans = info->invert;
}
if(info->hit_count && !info->seconds) {
for(pkt_count = 0, hits_found = 0; pkt_count < ip_pkt_list_tot; pkt_count++) {
if(r_list[location].last_pkts[pkt_count] == 0) break;
hits_found++;
}
if(hits_found >= info->hit_count) ans = !info->invert; else ans = info->invert;
}
}
#ifdef DEBUG
if(debug) {
if(ans)
printk(KERN_INFO RECENT_NAME ": match(): match addr: %u\n",addr);
else
printk(KERN_INFO RECENT_NAME ": match(): no match addr: %u\n",addr);
}
#endif
/* If and only if we have been asked to SET, or to UPDATE (on match) do we add the
* current timestamp to the last_seen. */
if((info->check_set & IPT_RECENT_SET && (ans = !info->invert)) || (info->check_set & IPT_RECENT_UPDATE && ans)) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): SET or UPDATE; updating time info.\n");
#endif
/* Have to update our time info */
time_loc = r_list[location].time_pos;
time_info[time_loc].time = now;
time_info[time_loc].position = location;
while((time_info[(time_loc+1) % ip_list_tot].time < time_info[time_loc].time) && ((time_loc+1) % ip_list_tot) != curr_table->time_pos) {
time_temp = time_info[time_loc].time;
time_info[time_loc].time = time_info[(time_loc+1)%ip_list_tot].time;
time_info[(time_loc+1)%ip_list_tot].time = time_temp;
time_temp = time_info[time_loc].position;
time_info[time_loc].position = time_info[(time_loc+1)%ip_list_tot].position;
time_info[(time_loc+1)%ip_list_tot].position = time_temp;
r_list[time_info[time_loc].position].time_pos = time_loc;
r_list[time_info[(time_loc+1)%ip_list_tot].position].time_pos = (time_loc+1)%ip_list_tot;
time_loc = (time_loc+1) % ip_list_tot;
}
r_list[location].time_pos = time_loc;
r_list[location].ttl = ttl;
r_list[location].last_pkts[r_list[location].oldest_pkt] = now;
r_list[location].oldest_pkt = ++r_list[location].oldest_pkt % ip_pkt_list_tot;
r_list[location].last_seen = now;
}
/* If we have been asked to remove the entry from the list, just set it to 0 */
if(info->check_set & IPT_RECENT_REMOVE) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): REMOVE; clearing entry (or: %d, hr: %d).\n",orig_hash_result,hash_result);
#endif
/* Check if this is part of a collision chain */
while(hash_table[(orig_hash_result+1) % ip_list_hash_size] != -1) {
orig_hash_result++;
if(hash_func(r_list[hash_table[orig_hash_result]].addr,ip_list_hash_size) == hash_result) {
/* Found collision chain, how deep does this rabbit hole go? */
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): REMOVE; found collision chain.\n");
#endif
end_collision_chain = orig_hash_result;
}
}
if(end_collision_chain != -1) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match(): REMOVE; part of collision chain, moving to end.\n");
#endif
/* Part of a collision chain, swap it with the end of the chain
* before removing. */
r_list[hash_table[end_collision_chain]].hash_entry = hash_result;
temp = hash_table[end_collision_chain];
hash_table[end_collision_chain] = hash_table[hash_result];
hash_table[hash_result] = temp;
time_info[r_list[hash_table[hash_result]].time_pos].position = hash_table[hash_result];
hash_result = end_collision_chain;
r_list[hash_table[hash_result]].hash_entry = hash_result;
time_info[r_list[hash_table[hash_result]].time_pos].position = hash_table[hash_result];
}
location = hash_table[hash_result];
hash_table[r_list[location].hash_entry] = -1;
time_loc = r_list[location].time_pos;
time_info[time_loc].time = 0;
time_info[time_loc].position = location;
while((time_info[(time_loc+1) % ip_list_tot].time < time_info[time_loc].time) && ((time_loc+1) % ip_list_tot) != curr_table->time_pos) {
time_temp = time_info[time_loc].time;
time_info[time_loc].time = time_info[(time_loc+1)%ip_list_tot].time;
time_info[(time_loc+1)%ip_list_tot].time = time_temp;
time_temp = time_info[time_loc].position;
time_info[time_loc].position = time_info[(time_loc+1)%ip_list_tot].position;
time_info[(time_loc+1)%ip_list_tot].position = time_temp;
r_list[time_info[time_loc].position].time_pos = time_loc;
r_list[time_info[(time_loc+1)%ip_list_tot].position].time_pos = (time_loc+1)%ip_list_tot;
time_loc = (time_loc+1) % ip_list_tot;
}
r_list[location].time_pos = time_loc;
r_list[location].last_seen = 0;
r_list[location].addr = 0;
r_list[location].ttl = 0;
memset(r_list[location].last_pkts,0,ip_pkt_list_tot*sizeof(unsigned long));
r_list[location].oldest_pkt = 0;
ans = !info->invert;
}
spin_unlock_bh(&curr_table->list_lock);
return ans;
}
spin_unlock_bh(&curr_table->list_lock);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": match() left.\n");
#endif
return ans;
}
/* This function is to verify that the rule given during the userspace iptables
* command is correct.
* If the command is valid then we check if the table name referred to by the
* rule exists, if not it is created.
*/
static int
checkentry(const char *tablename,
const struct ipt_ip *ip,
void *matchinfo,
unsigned int matchsize,
unsigned int hook_mask)
{
int flag = 0, c;
unsigned long *hold;
const struct ipt_recent_info *info = matchinfo;
struct recent_ip_tables *curr_table, *find_table, *last_table;
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry() entered.\n");
#endif
if (matchsize != IPT_ALIGN(sizeof(struct ipt_recent_info))) return 0;
/* seconds and hit_count only valid for CHECK/UPDATE */
if(info->check_set & IPT_RECENT_SET) { flag++; if(info->seconds || info->hit_count) return 0; }
if(info->check_set & IPT_RECENT_REMOVE) { flag++; if(info->seconds || info->hit_count) return 0; }
if(info->check_set & IPT_RECENT_CHECK) flag++;
if(info->check_set & IPT_RECENT_UPDATE) flag++;
/* One and only one of these should ever be set */
if(flag != 1) return 0;
/* Name must be set to something */
if(!info->name || !info->name[0]) return 0;
/* Things look good, create a list for this if it does not exist */
/* Lock the linked list while we play with it */
spin_lock_bh(&recent_lock);
/* Look for an entry with this name already created */
/* Finds the end of the list and the entry before the end if current name does not exist */
find_table = r_tables;
while( (last_table = find_table) && strncmp(info->name,find_table->name,IPT_RECENT_NAME_LEN) && (find_table = find_table->next) );
/* If a table already exists just increment the count on that table and return */
if(find_table) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: table found (%s), incrementing count.\n",info->name);
#endif
find_table->count++;
spin_unlock_bh(&recent_lock);
return 1;
}
spin_unlock_bh(&recent_lock);
/* Table with this name not found */
/* Allocate memory for new linked list item */
#ifdef DEBUG
if(debug) {
printk(KERN_INFO RECENT_NAME ": checkentry: no table found (%s)\n",info->name);
printk(KERN_INFO RECENT_NAME ": checkentry: Allocationg %d for link-list entry.\n",sizeof(struct recent_ip_tables));
}
#endif
curr_table = vmalloc(sizeof(struct recent_ip_tables));
if(curr_table == NULL) return 0;
spin_lock_init(&curr_table->list_lock);
curr_table->next = NULL;
curr_table->count = 1;
curr_table->time_pos = 0;
strncpy(curr_table->name,info->name,IPT_RECENT_NAME_LEN);
curr_table->name[IPT_RECENT_NAME_LEN-1] = '\0';
/* Allocate memory for this table and the list of packets in each entry. */
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: Allocating %d for table (%s).\n",
sizeof(struct recent_ip_list)*ip_list_tot,
info->name);
#endif
curr_table->table = vmalloc(sizeof(struct recent_ip_list)*ip_list_tot);
if(curr_table->table == NULL) { vfree(curr_table); return 0; }
memset(curr_table->table,0,sizeof(struct recent_ip_list)*ip_list_tot);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: Allocating %d for pkt_list.\n",
sizeof(unsigned long)*ip_pkt_list_tot*ip_list_tot);
#endif
hold = vmalloc(sizeof(unsigned long)*ip_pkt_list_tot*ip_list_tot);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: After pkt_list allocation.\n");
#endif
if(hold == NULL) {
printk(KERN_INFO RECENT_NAME ": checkentry: unable to allocate for pkt_list.\n");
vfree(curr_table->table);
vfree(curr_table);
return 0;
}
for(c = 0; c < ip_list_tot; c++) {
curr_table->table[c].last_pkts = hold + c*ip_pkt_list_tot;
}
/* Allocate memory for the hash table */
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: Allocating %d for hash_table.\n",
sizeof(int)*ip_list_hash_size);
#endif
curr_table->hash_table = vmalloc(sizeof(int)*ip_list_hash_size);
if(!curr_table->hash_table) {
printk(KERN_INFO RECENT_NAME ": checkentry: unable to allocate for hash_table.\n");
vfree(hold);
vfree(curr_table->table);
vfree(curr_table);
return 0;
}
for(c = 0; c < ip_list_hash_size; c++) {
curr_table->hash_table[c] = -1;
}
/* Allocate memory for the time info */
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: Allocating %d for time_info.\n",
sizeof(struct time_info_list)*ip_list_tot);
#endif
curr_table->time_info = vmalloc(sizeof(struct time_info_list)*ip_list_tot);
if(!curr_table->time_info) {
printk(KERN_INFO RECENT_NAME ": checkentry: unable to allocate for time_info.\n");
vfree(curr_table->hash_table);
vfree(hold);
vfree(curr_table->table);
vfree(curr_table);
return 0;
}
for(c = 0; c < ip_list_tot; c++) {
curr_table->time_info[c].position = c;
curr_table->time_info[c].time = 0;
}
/* Put the new table in place */
spin_lock_bh(&recent_lock);
find_table = r_tables;
while( (last_table = find_table) && strncmp(info->name,find_table->name,IPT_RECENT_NAME_LEN) && (find_table = find_table->next) );
/* If a table already exists just increment the count on that table and return */
if(find_table) {
find_table->count++;
spin_unlock_bh(&recent_lock);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry: table found (%s), created by other process.\n",info->name);
#endif
vfree(curr_table->time_info);
vfree(curr_table->hash_table);
vfree(hold);
vfree(curr_table->table);
vfree(curr_table);
return 1;
}
if(!last_table) r_tables = curr_table; else last_table->next = curr_table;
spin_unlock_bh(&recent_lock);
#ifdef CONFIG_PROC_FS
/* Create our proc 'status' entry. */
curr_table->status_proc = create_proc_entry(curr_table->name, ip_list_perms, proc_net_ipt_recent);
if (!curr_table->status_proc) {
printk(KERN_INFO RECENT_NAME ": checkentry: unable to allocate for /proc entry.\n");
/* Destroy the created table */
spin_lock_bh(&recent_lock);
last_table = NULL;
curr_table = r_tables;
if(!curr_table) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry() create_proc failed, no tables.\n");
#endif
spin_unlock_bh(&recent_lock);
return 0;
}
while( strncmp(info->name,curr_table->name,IPT_RECENT_NAME_LEN) && (last_table = curr_table) && (curr_table = curr_table->next) );
if(!curr_table) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry() create_proc failed, table already destroyed.\n");
#endif
spin_unlock_bh(&recent_lock);
return 0;
}
if(last_table) last_table->next = curr_table->next; else r_tables = curr_table->next;
spin_unlock_bh(&recent_lock);
vfree(curr_table->time_info);
vfree(curr_table->hash_table);
vfree(hold);
vfree(curr_table->table);
vfree(curr_table);
return 0;
}
curr_table->status_proc->owner = THIS_MODULE;
curr_table->status_proc->data = curr_table;
wmb();
curr_table->status_proc->read_proc = ip_recent_get_info;
curr_table->status_proc->write_proc = ip_recent_ctrl;
#endif /* CONFIG_PROC_FS */
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": checkentry() left.\n");
#endif
return 1;
}
/* This function is called in the event that a rule matching this module is
* removed.
* When this happens we need to check if there are no other rules matching
* the table given. If that is the case then we remove the table and clean
* up its memory.
*/
static void
destroy(void *matchinfo, unsigned int matchsize)
{
const struct ipt_recent_info *info = matchinfo;
struct recent_ip_tables *curr_table, *last_table;
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": destroy() entered.\n");
#endif
if(matchsize != IPT_ALIGN(sizeof(struct ipt_recent_info))) return;
/* Lock the linked list while we play with it */
spin_lock_bh(&recent_lock);
/* Look for an entry with this name already created */
/* Finds the end of the list and the entry before the end if current name does not exist */
last_table = NULL;
curr_table = r_tables;
if(!curr_table) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": destroy() No tables found, leaving.\n");
#endif
spin_unlock_bh(&recent_lock);
return;
}
while( strncmp(info->name,curr_table->name,IPT_RECENT_NAME_LEN) && (last_table = curr_table) && (curr_table = curr_table->next) );
/* If a table does not exist then do nothing and return */
if(!curr_table) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": destroy() table not found, leaving.\n");
#endif
spin_unlock_bh(&recent_lock);
return;
}
curr_table->count--;
/* If count is still non-zero then there are still rules referenceing it so we do nothing */
if(curr_table->count) {
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": destroy() table found, non-zero count, leaving.\n");
#endif
spin_unlock_bh(&recent_lock);
return;
}
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": destroy() table found, zero count, removing.\n");
#endif
/* Count must be zero so we remove this table from the list */
if(last_table) last_table->next = curr_table->next; else r_tables = curr_table->next;
spin_unlock_bh(&recent_lock);
/* lock to make sure any late-runners still using this after we removed it from
* the list finish up then remove everything */
spin_lock_bh(&curr_table->list_lock);
spin_unlock_bh(&curr_table->list_lock);
#ifdef CONFIG_PROC_FS
if(curr_table->status_proc) remove_proc_entry(curr_table->name,proc_net_ipt_recent);
#endif /* CONFIG_PROC_FS */
vfree(curr_table->table[0].last_pkts);
vfree(curr_table->table);
vfree(curr_table->hash_table);
vfree(curr_table->time_info);
vfree(curr_table);
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": destroy() left.\n");
#endif
return;
}
/* This is the structure we pass to ipt_register to register our
* module with iptables.
*/
static struct ipt_match recent_match = {
.name = "recent",
.match = &match,
.checkentry = &checkentry,
.destroy = &destroy,
.me = THIS_MODULE
};
/* Kernel module initialization. */
static int __init init(void)
{
int err, count;
printk(version);
#ifdef CONFIG_PROC_FS
proc_net_ipt_recent = proc_mkdir("ipt_recent",proc_net);
if(!proc_net_ipt_recent) return -ENOMEM;
#endif
if(ip_list_hash_size && ip_list_hash_size <= ip_list_tot) {
printk(KERN_WARNING RECENT_NAME ": ip_list_hash_size too small, resetting to default.\n");
ip_list_hash_size = 0;
}
if(!ip_list_hash_size) {
ip_list_hash_size = ip_list_tot*3;
count = 2*2;
while(ip_list_hash_size > count) count = count*2;
ip_list_hash_size = count;
}
#ifdef DEBUG
if(debug) printk(KERN_INFO RECENT_NAME ": ip_list_hash_size: %d\n",ip_list_hash_size);
#endif
err = ipt_register_match(&recent_match);
if (err)
remove_proc_entry("ipt_recent", proc_net);
return err;
}
/* Kernel module destruction. */
static void __exit fini(void)
{
ipt_unregister_match(&recent_match);
remove_proc_entry("ipt_recent",proc_net);
}
/* Register our module with the kernel. */
module_init(init);
module_exit(fini);
