| /* 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_ipv4/ip_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 |
| target(struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| unsigned int hooknum, |
| const void *targinfo, |
| void *userinfo) |
| { |
| const struct ipt_tos_target_info *tosinfo = targinfo; |
| |
| if (((*pskb)->nh.iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) { |
| u_int16_t diffs[2]; |
| |
| if (!skb_make_writable(pskb, sizeof(struct iphdr))) |
| return NF_DROP; |
| |
| diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF; |
| (*pskb)->nh.iph->tos |
| = ((*pskb)->nh.iph->tos & IPTOS_PREC_MASK) |
| | tosinfo->tos; |
| diffs[1] = htons((*pskb)->nh.iph->tos); |
| (*pskb)->nh.iph->check |
| = csum_fold(csum_partial((char *)diffs, |
| sizeof(diffs), |
| (*pskb)->nh.iph->check |
| ^0xFFFF)); |
| } |
| return IPT_CONTINUE; |
| } |
| |
| static int |
| checkentry(const char *tablename, |
| const struct ipt_entry *e, |
| void *targinfo, |
| unsigned int targinfosize, |
| unsigned int hook_mask) |
| { |
| const u_int8_t tos = ((struct ipt_tos_target_info *)targinfo)->tos; |
| |
| if (targinfosize != IPT_ALIGN(sizeof(struct ipt_tos_target_info))) { |
| printk(KERN_WARNING "TOS: targinfosize %u != %Zu\n", |
| targinfosize, |
| IPT_ALIGN(sizeof(struct ipt_tos_target_info))); |
| return 0; |
| } |
| |
| if (strcmp(tablename, "mangle") != 0) { |
| printk(KERN_WARNING "TOS: can only be called from \"mangle\" table, not \"%s\"\n", tablename); |
| return 0; |
| } |
| |
| 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 0; |
| } |
| |
| return 1; |
| } |
| |
| static struct ipt_target ipt_tos_reg = { |
| .name = "TOS", |
| .target = target, |
| .checkentry = checkentry, |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init init(void) |
| { |
| return ipt_register_target(&ipt_tos_reg); |
| } |
| |
| static void __exit fini(void) |
| { |
| ipt_unregister_target(&ipt_tos_reg); |
| } |
| |
| module_init(init); |
| module_exit(fini); |