diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv4/netfilter/ipt_recent.c | |
download | kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz kernel_samsung_smdk4412-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'net/ipv4/netfilter/ipt_recent.c')
-rw-r--r-- | net/ipv4/netfilter/ipt_recent.c | 1002 |
1 files changed, 1002 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_recent.c b/net/ipv4/netfilter/ipt_recent.c new file mode 100644 index 0000000..25ab9fa --- /dev/null +++ b/net/ipv4/netfilter/ipt_recent.c @@ -0,0 +1,1002 @@ +/* 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(u_int32_t)); + 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(u_int32_t)); + 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(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(u_int32_t)); + 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(u_int32_t)*ip_pkt_list_tot*ip_list_tot); +#endif + + hold = vmalloc(sizeof(u_int32_t)*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); |