| /* This is a module which is used for setting the TOS field of a packet. */ |
| |
| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 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/skbuff.h> |
| #include <linux/ip.h> |
| #include <net/checksum.h> |
| |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter_ipv4/ipt_TOS.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| MODULE_DESCRIPTION("iptables TOS mangling module"); |
| |
| static unsigned int |
| tos_tg(struct sk_buff *skb, const struct net_device *in, |
| const struct net_device *out, unsigned int hooknum, |
| const struct xt_target *target, const void *targinfo) |
| { |
| const struct ipt_tos_target_info *tosinfo = targinfo; |
| struct iphdr *iph = ip_hdr(skb); |
| |
| if ((iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) { |
| __u8 oldtos; |
| if (!skb_make_writable(skb, sizeof(struct iphdr))) |
| return NF_DROP; |
| iph = ip_hdr(skb); |
| oldtos = iph->tos; |
| iph->tos = (iph->tos & IPTOS_PREC_MASK) | tosinfo->tos; |
| csum_replace2(&iph->check, htons(oldtos), htons(iph->tos)); |
| } |
| return XT_CONTINUE; |
| } |
| |
| static bool |
| tos_tg_check(const char *tablename, const void *e_void, |
| const struct xt_target *target, void *targinfo, |
| unsigned int hook_mask) |
| { |
| const u_int8_t tos = ((struct ipt_tos_target_info *)targinfo)->tos; |
| |
| if (tos != IPTOS_LOWDELAY |
| && tos != IPTOS_THROUGHPUT |
| && tos != IPTOS_RELIABILITY |
| && tos != IPTOS_MINCOST |
| && tos != IPTOS_NORMALSVC) { |
| printk(KERN_WARNING "TOS: bad tos value %#x\n", tos); |
| return false; |
| } |
| return true; |
| } |
| |
| static struct xt_target tos_tg_reg __read_mostly = { |
| .name = "TOS", |
| .family = AF_INET, |
| .target = tos_tg, |
| .targetsize = sizeof(struct ipt_tos_target_info), |
| .table = "mangle", |
| .checkentry = tos_tg_check, |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init tos_tg_init(void) |
| { |
| return xt_register_target(&tos_tg_reg); |
| } |
| |
| static void __exit tos_tg_exit(void) |
| { |
| xt_unregister_target(&tos_tg_reg); |
| } |
| |
| module_init(tos_tg_init); |
| module_exit(tos_tg_exit); |