/* * Copyright (c) 2006 Patrick McHardy * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This is a replacement of the old ipt_recent module, which carried the * following copyright notice: * * Author: Stephen Frost * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include MODULE_AUTHOR("Patrick McHardy "); MODULE_DESCRIPTION("IP tables recently seen matching module"); MODULE_LICENSE("GPL"); static unsigned int ip_list_tot = 100; static unsigned int ip_pkt_list_tot = 20; static unsigned int ip_list_hash_size = 0; static unsigned int ip_list_perms = 0644; static unsigned int ip_list_uid = 0; static unsigned int ip_list_gid = 0; module_param(ip_list_tot, uint, 0400); module_param(ip_pkt_list_tot, uint, 0400); module_param(ip_list_hash_size, uint, 0400); module_param(ip_list_perms, uint, 0400); module_param(ip_list_uid, uint, 0400); module_param(ip_list_gid, uint, 0400); 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 (max. 255)"); 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"); MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/ipt_recent/* files"); MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/ipt_recent/* files"); struct recent_entry { struct list_head list; struct list_head lru_list; __be32 addr; u_int8_t ttl; u_int8_t index; u_int16_t nstamps; unsigned long stamps[0]; }; struct recent_table { struct list_head list; char name[IPT_RECENT_NAME_LEN]; #ifdef CONFIG_PROC_FS struct proc_dir_entry *proc; #endif unsigned int refcnt; unsigned int entries; struct list_head lru_list; struct list_head iphash[0]; }; static LIST_HEAD(tables); static DEFINE_SPINLOCK(recent_lock); static DEFINE_MUTEX(recent_mutex); #ifdef CONFIG_PROC_FS static struct proc_dir_entry *proc_dir; static struct file_operations recent_fops; #endif static u_int32_t hash_rnd; static int hash_rnd_initted; static unsigned int recent_entry_hash(__be32 addr) { if (!hash_rnd_initted) { get_random_bytes(&hash_rnd, 4); hash_rnd_initted = 1; } return jhash_1word((__force u32)addr, hash_rnd) & (ip_list_hash_size - 1); } static struct recent_entry * recent_entry_lookup(const struct recent_table *table, __be32 addr, u_int8_t ttl) { struct recent_entry *e; unsigned int h; h = recent_entry_hash(addr); list_for_each_entry(e, &table->iphash[h], list) if (e->addr == addr && (ttl == e->ttl || !ttl || !e->ttl)) return e; return NULL; } static void recent_entry_remove(struct recent_table *t, struct recent_entry *e) { list_del(&e->list); list_del(&e->lru_list); kfree(e); t->entries--; } static struct recent_entry * recent_entry_init(struct recent_table *t, __be32 addr, u_int8_t ttl) { struct recent_entry *e; if (t->entries >= ip_list_tot) { e = list_entry(t->lru_list.next, struct recent_entry, lru_list); recent_entry_remove(t, e); } e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot, GFP_ATOMIC); if (e == NULL) return NULL; e->addr = addr; e->ttl = ttl; e->stamps[0] = jiffies; e->nstamps = 1; e->index = 1; list_add_tail(&e->list, &t->iphash[recent_entry_hash(addr)]); list_add_tail(&e->lru_list, &t->lru_list); t->entries++; return e; } static void recent_entry_update(struct recent_table *t, struct recent_entry *e) { e->stamps[e->index++] = jiffies; if (e->index > e->nstamps) e->nstamps = e->index; e->index %= ip_pkt_list_tot; list_move_tail(&e->lru_list, &t->lru_list); } static struct recent_table *recent_table_lookup(const char *name) { struct recent_table *t; list_for_each_entry(t, &tables, list) if (!strcmp(t->name, name)) return t; return NULL; } static void recent_table_flush(struct recent_table *t) { struct recent_entry *e, *next; unsigned int i; for (i = 0; i < ip_list_hash_size; i++) { list_for_each_entry_safe(e, next, &t->iphash[i], list) recent_entry_remove(t, e); } } static int ipt_recent_match(const struct sk_buff *skb, const struct net_device *in, const struct net_device *out, const struct xt_match *match, const void *matchinfo, int offset, unsigned int protoff, int *hotdrop) { const struct ipt_recent_info *info = matchinfo; struct recent_table *t; struct recent_entry *e; __be32 addr; u_int8_t ttl; int ret = info->invert; if (info->side == IPT_RECENT_DEST) addr = skb->nh.iph->daddr; else addr = skb->nh.iph->saddr; ttl = skb->nh.iph->ttl; /* use TTL as seen before forwarding */ if (out && !skb->sk) ttl++; spin_lock_bh(&recent_lock); t = recent_table_lookup(info->name); e = recent_entry_lookup(t, addr, info->check_set & IPT_RECENT_TTL ? ttl : 0); if (e == NULL) { if (!(info->check_set & IPT_RECENT_SET)) goto out; e = recent_entry_init(t, addr, ttl); if (e == NULL) *hotdrop = 1; ret ^= 1; goto out; } if (info->check_set & IPT_RECENT_SET) ret ^= 1; else if (info->check_set & IPT_RECENT_REMOVE) { recent_entry_remove(t, e); ret ^= 1; } else if (info->check_set & (IPT_RECENT_CHECK | IPT_RECENT_UPDATE)) { unsigned long t = jiffies - info->seconds * HZ; unsigned int i, hits = 0; for (i = 0; i < e->nstamps; i++) { if (info->seconds && time_after(t, e->stamps[i])) continue; if (++hits >= info->hit_count) { ret ^= 1; break; } } } if (info->check_set & IPT_RECENT_SET || (info->check_set & IPT_RECENT_UPDATE && ret)) { recent_entry_update(t, e); e->ttl = ttl; } out: spin_unlock_bh(&recent_lock); return ret; } static int ipt_recent_checkentry(const char *tablename, const void *ip, const struct xt_match *match, void *matchinfo, unsigned int hook_mask) { const struct ipt_recent_info *info = matchinfo; struct recent_table *t; unsigned i; int ret = 0; if (hweight8(info->check_set & (IPT_RECENT_SET | IPT_RECENT_REMOVE | IPT_RECENT_CHECK | IPT_RECENT_UPDATE)) != 1) return 0; if ((info->check_set & (IPT_RECENT_SET | IPT_RECENT_REMOVE)) && (info->seconds || info->hit_count)) return 0; if (info->name[0] == '\0' || strnlen(info->name, IPT_RECENT_NAME_LEN) == IPT_RECENT_NAME_LEN) return 0; mutex_lock(&recent_mutex); t = recent_table_lookup(info->name); if (t != NULL) { t->refcnt++; ret = 1; goto out; } t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size, GFP_KERNEL); if (t == NULL) goto out; t->refcnt = 1; strcpy(t->name, info->name); INIT_LIST_HEAD(&t->lru_list); for (i = 0; i < ip_list_hash_size; i++) INIT_LIST_HEAD(&t->iphash[i]); #ifdef CONFIG_PROC_FS t->proc = create_proc_entry(t->name, ip_list_perms, proc_dir); if (t->proc == NULL) { kfree(t); goto out; } t->proc->proc_fops = &recent_fops; t->proc->uid = ip_list_uid; t->proc->gid = ip_list_gid; t->proc->data = t; #endif spin_lock_bh(&recent_lock); list_add_tail(&t->list, &tables); spin_unlock_bh(&recent_lock); ret = 1; out: mutex_unlock(&recent_mutex); return ret; } static void ipt_recent_destroy(const struct xt_match *match, void *matchinfo) { const struct ipt_recent_info *info = matchinfo; struct recent_table *t; mutex_lock(&recent_mutex); t = recent_table_lookup(info->name); if (--t->refcnt == 0) { spin_lock_bh(&recent_lock); list_del(&t->list); spin_unlock_bh(&recent_lock); recent_table_flush(t); #ifdef CONFIG_PROC_FS remove_proc_entry(t->name, proc_dir); #endif kfree(t); } mutex_unlock(&recent_mutex); } #ifdef CONFIG_PROC_FS struct recent_iter_state { struct recent_table *table; unsigned int bucket; }; static void *recent_seq_start(struct seq_file *seq, loff_t *pos) { struct recent_iter_state *st = seq->private; struct recent_table *t = st->table; struct recent_entry *e; loff_t p = *pos; spin_lock_bh(&recent_lock); for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++) { list_for_each_entry(e, &t->iphash[st->bucket], list) { if (p-- == 0) return e; } } return NULL; } static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos) { struct recent_iter_state *st = seq->private; struct recent_table *t = st->table; struct recent_entry *e = v; struct list_head *head = e->list.next; while (head == &t->iphash[st->bucket]) { if (++st->bucket >= ip_list_hash_size) return NULL; head = t->iphash[st->bucket].next; } (*pos)++; return list_entry(head, struct recent_entry, list); } static void recent_seq_stop(struct seq_file *s, void *v) { spin_unlock_bh(&recent_lock); } static int recent_seq_show(struct seq_file *seq, void *v) { struct recent_entry *e = v; unsigned int i; i = (e->index - 1) % ip_pkt_list_tot; seq_printf(seq, "src=%u.%u.%u.%u ttl: %u last_seen: %lu oldest_pkt: %u", NIPQUAD(e->addr), e->ttl, e->stamps[i], e->index); for (i = 0; i < e->nstamps; i++) seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]); seq_printf(seq, "\n"); return 0; } static struct seq_operations recent_seq_ops = { .start = recent_seq_start, .next = recent_seq_next, .stop = recent_seq_stop, .show = recent_seq_show, }; static int recent_seq_open(struct inode *inode, struct file *file) { struct proc_dir_entry *pde = PDE(inode); struct seq_file *seq; struct recent_iter_state *st; int ret; st = kzalloc(sizeof(*st), GFP_KERNEL); if (st == NULL) return -ENOMEM; ret = seq_open(file, &recent_seq_ops); if (ret) kfree(st); st->table = pde->data; seq = file->private_data; seq->private = st; return ret; } static ssize_t recent_proc_write(struct file *file, const char __user *input, size_t size, loff_t *loff) { struct proc_dir_entry *pde = PDE(file->f_dentry->d_inode); struct recent_table *t = pde->data; struct recent_entry *e; char buf[sizeof("+255.255.255.255")], *c = buf; __be32 addr; int add; if (size > sizeof(buf)) size = sizeof(buf); if (copy_from_user(buf, input, size)) return -EFAULT; while (isspace(*c)) c++; if (size - (c - buf) < 5) return c - buf; if (!strncmp(c, "clear", 5)) { c += 5; spin_lock_bh(&recent_lock); recent_table_flush(t); spin_unlock_bh(&recent_lock); return c - buf; } switch (*c) { case '-': add = 0; c++; break; case '+': c++; default: add = 1; break; } addr = in_aton(c); spin_lock_bh(&recent_lock); e = recent_entry_lookup(t, addr, 0); if (e == NULL) { if (add) recent_entry_init(t, addr, 0); } else { if (add) recent_entry_update(t, e); else recent_entry_remove(t, e); } spin_unlock_bh(&recent_lock); return size; } static struct file_operations recent_fops = { .open = recent_seq_open, .read = seq_read, .write = recent_proc_write, .release = seq_release_private, .owner = THIS_MODULE, }; #endif /* CONFIG_PROC_FS */ static struct ipt_match recent_match = { .name = "recent", .match = ipt_recent_match, .matchsize = sizeof(struct ipt_recent_info), .checkentry = ipt_recent_checkentry, .destroy = ipt_recent_destroy, .me = THIS_MODULE, }; static int __init ipt_recent_init(void) { int err; if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255) return -EINVAL; ip_list_hash_size = 1 << fls(ip_list_tot); err = ipt_register_match(&recent_match); #ifdef CONFIG_PROC_FS if (err) return err; proc_dir = proc_mkdir("ipt_recent", proc_net); if (proc_dir == NULL) { ipt_unregister_match(&recent_match); err = -ENOMEM; } #endif return err; } static void __exit ipt_recent_exit(void) { BUG_ON(!list_empty(&tables)); ipt_unregister_match(&recent_match); #ifdef CONFIG_PROC_FS remove_proc_entry("ipt_recent", proc_net); #endif } module_init(ipt_recent_init); module_exit(ipt_recent_exit);