diff options
Diffstat (limited to 'net/ipv6/netfilter/ip6table_mangle.c')
| -rw-r--r-- | net/ipv6/netfilter/ip6table_mangle.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/net/ipv6/netfilter/ip6table_mangle.c b/net/ipv6/netfilter/ip6table_mangle.c new file mode 100644 index 00000000..00d19173 --- /dev/null +++ b/net/ipv6/netfilter/ip6table_mangle.c @@ -0,0 +1,145 @@ +/* + * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6 + * + * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org> + * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> + * + * 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/netfilter_ipv6/ip6_tables.h> +#include <linux/slab.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); +MODULE_DESCRIPTION("ip6tables mangle table"); + +#define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \ + (1 << NF_INET_LOCAL_IN) | \ + (1 << NF_INET_FORWARD) | \ + (1 << NF_INET_LOCAL_OUT) | \ + (1 << NF_INET_POST_ROUTING)) + +static const struct xt_table packet_mangler = { + .name = "mangle", + .valid_hooks = MANGLE_VALID_HOOKS, + .me = THIS_MODULE, + .af = NFPROTO_IPV6, + .priority = NF_IP6_PRI_MANGLE, +}; + +static unsigned int +ip6t_mangle_out(struct sk_buff *skb, const struct net_device *out) +{ + unsigned int ret; + struct in6_addr saddr, daddr; + u_int8_t hop_limit; + u_int32_t flowlabel, mark; + +#if 0 + /* root is playing with raw sockets. */ + if (skb->len < sizeof(struct iphdr) || + ip_hdrlen(skb) < sizeof(struct iphdr)) { + if (net_ratelimit()) + pr_warning("ip6t_hook: happy cracking.\n"); + return NF_ACCEPT; + } +#endif + + /* save source/dest address, mark, hoplimit, flowlabel, priority, */ + memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr)); + memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr)); + mark = skb->mark; + hop_limit = ipv6_hdr(skb)->hop_limit; + + /* flowlabel and prio (includes version, which shouldn't change either */ + flowlabel = *((u_int32_t *)ipv6_hdr(skb)); + + ret = ip6t_do_table(skb, NF_INET_LOCAL_OUT, NULL, out, + dev_net(out)->ipv6.ip6table_mangle); + + if (ret != NF_DROP && ret != NF_STOLEN && + (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) || + memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) || + skb->mark != mark || + ipv6_hdr(skb)->hop_limit != hop_limit || + flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) + return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP; + + return ret; +} + +/* The work comes in here from netfilter.c. */ +static unsigned int +ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb, + const struct net_device *in, const struct net_device *out, + int (*okfn)(struct sk_buff *)) +{ + if (hook == NF_INET_LOCAL_OUT) + return ip6t_mangle_out(skb, out); + if (hook == NF_INET_POST_ROUTING) + return ip6t_do_table(skb, hook, in, out, + dev_net(out)->ipv6.ip6table_mangle); + /* INPUT/FORWARD */ + return ip6t_do_table(skb, hook, in, out, + dev_net(in)->ipv6.ip6table_mangle); +} + +static struct nf_hook_ops *mangle_ops __read_mostly; +static int __net_init ip6table_mangle_net_init(struct net *net) +{ + struct ip6t_replace *repl; + + repl = ip6t_alloc_initial_table(&packet_mangler); + if (repl == NULL) + return -ENOMEM; + net->ipv6.ip6table_mangle = + ip6t_register_table(net, &packet_mangler, repl); + kfree(repl); + if (IS_ERR(net->ipv6.ip6table_mangle)) + return PTR_ERR(net->ipv6.ip6table_mangle); + return 0; +} + +static void __net_exit ip6table_mangle_net_exit(struct net *net) +{ + ip6t_unregister_table(net, net->ipv6.ip6table_mangle); +} + +static struct pernet_operations ip6table_mangle_net_ops = { + .init = ip6table_mangle_net_init, + .exit = ip6table_mangle_net_exit, +}; + +static int __init ip6table_mangle_init(void) +{ + int ret; + + ret = register_pernet_subsys(&ip6table_mangle_net_ops); + if (ret < 0) + return ret; + + /* Register hooks */ + mangle_ops = xt_hook_link(&packet_mangler, ip6table_mangle_hook); + if (IS_ERR(mangle_ops)) { + ret = PTR_ERR(mangle_ops); + goto cleanup_table; + } + + return ret; + + cleanup_table: + unregister_pernet_subsys(&ip6table_mangle_net_ops); + return ret; +} + +static void __exit ip6table_mangle_fini(void) +{ + xt_hook_unlink(&packet_mangler, mangle_ops); + unregister_pernet_subsys(&ip6table_mangle_net_ops); +} + +module_init(ip6table_mangle_init); +module_exit(ip6table_mangle_fini); |