diff options
Diffstat (limited to 'net/netfilter/xt_helper.c')
| -rw-r--r-- | net/netfilter/xt_helper.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/net/netfilter/xt_helper.c b/net/netfilter/xt_helper.c new file mode 100644 index 0000000000000..38b6715e1db41 --- /dev/null +++ b/net/netfilter/xt_helper.c @@ -0,0 +1,188 @@ +/* iptables module to match on related connections */ +/* + * (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se> + * + * 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. + * + * 19 Mar 2002 Harald Welte <laforge@gnumonks.org>: + * - Port to newnat infrastructure + */ + +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/netfilter.h> +#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE) +#include <linux/netfilter_ipv4/ip_conntrack.h> +#include <linux/netfilter_ipv4/ip_conntrack_core.h> +#include <linux/netfilter_ipv4/ip_conntrack_helper.h> +#else +#include <net/netfilter/nf_conntrack.h> +#include <net/netfilter/nf_conntrack_core.h> +#include <net/netfilter/nf_conntrack_helper.h> +#endif +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_helper.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>"); +MODULE_DESCRIPTION("iptables helper match module"); +MODULE_ALIAS("ipt_helper"); +MODULE_ALIAS("ip6t_helper"); + +#if 0 +#define DEBUGP printk +#else +#define DEBUGP(format, args...) +#endif + +#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE) +static int +match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + unsigned int protoff, + int *hotdrop) +{ + const struct xt_helper_info *info = matchinfo; + struct ip_conntrack *ct; + enum ip_conntrack_info ctinfo; + int ret = info->invert; + + ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo); + if (!ct) { + DEBUGP("xt_helper: Eek! invalid conntrack?\n"); + return ret; + } + + if (!ct->master) { + DEBUGP("xt_helper: conntrack %p has no master\n", ct); + return ret; + } + + read_lock_bh(&ip_conntrack_lock); + if (!ct->master->helper) { + DEBUGP("xt_helper: master ct %p has no helper\n", + exp->expectant); + goto out_unlock; + } + + DEBUGP("master's name = %s , info->name = %s\n", + ct->master->helper->name, info->name); + + if (info->name[0] == '\0') + ret ^= 1; + else + ret ^= !strncmp(ct->master->helper->name, info->name, + strlen(ct->master->helper->name)); +out_unlock: + read_unlock_bh(&ip_conntrack_lock); + return ret; +} + +#else /* CONFIG_IP_NF_CONNTRACK */ + +static int +match(const struct sk_buff *skb, + const struct net_device *in, + const struct net_device *out, + const void *matchinfo, + int offset, + unsigned int protoff, + int *hotdrop) +{ + const struct xt_helper_info *info = matchinfo; + struct nf_conn *ct; + enum ip_conntrack_info ctinfo; + int ret = info->invert; + + ct = nf_ct_get((struct sk_buff *)skb, &ctinfo); + if (!ct) { + DEBUGP("xt_helper: Eek! invalid conntrack?\n"); + return ret; + } + + if (!ct->master) { + DEBUGP("xt_helper: conntrack %p has no master\n", ct); + return ret; + } + + read_lock_bh(&nf_conntrack_lock); + if (!ct->master->helper) { + DEBUGP("xt_helper: master ct %p has no helper\n", + exp->expectant); + goto out_unlock; + } + + DEBUGP("master's name = %s , info->name = %s\n", + ct->master->helper->name, info->name); + + if (info->name[0] == '\0') + ret ^= 1; + else + ret ^= !strncmp(ct->master->helper->name, info->name, + strlen(ct->master->helper->name)); +out_unlock: + read_unlock_bh(&nf_conntrack_lock); + return ret; +} +#endif + +static int check(const char *tablename, + const void *inf, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + struct xt_helper_info *info = matchinfo; + + info->name[29] = '\0'; + + /* verify size */ + if (matchsize != XT_ALIGN(sizeof(struct xt_helper_info))) + return 0; + + return 1; +} + +static struct xt_match helper_match = { + .name = "helper", + .match = &match, + .checkentry = &check, + .me = THIS_MODULE, +}; +static struct xt_match helper6_match = { + .name = "helper", + .match = &match, + .checkentry = &check, + .me = THIS_MODULE, +}; + +static int __init init(void) +{ + int ret; + need_conntrack(); + + ret = xt_register_match(AF_INET, &helper_match); + if (ret < 0) + return ret; + + ret = xt_register_match(AF_INET6, &helper6_match); + if (ret < 0) + xt_unregister_match(AF_INET, &helper_match); + + return ret; +} + +static void __exit fini(void) +{ + xt_unregister_match(AF_INET, &helper_match); + xt_unregister_match(AF_INET6, &helper6_match); +} + +module_init(init); +module_exit(fini); + |