| /* x_tables module for setting the IPv4/IPv6 DSCP field, Version 1.8 |
| * |
| * (C) 2002 by Harald Welte <laforge@netfilter.org> |
| * based on ipt_FTOS.c (C) 2000 by Matthew G. Marsh <mgm@paktronix.com> |
| * |
| * 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. |
| * |
| * See RFC2474 for a description of the DSCP field within the IP Header. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/skbuff.h> |
| #include <linux/ip.h> |
| #include <linux/ipv6.h> |
| #include <net/dsfield.h> |
| |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter/xt_DSCP.h> |
| #include <linux/netfilter_ipv4/ipt_TOS.h> |
| |
| MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| MODULE_DESCRIPTION("Xtables: DSCP/TOS field modification"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("ipt_DSCP"); |
| MODULE_ALIAS("ip6t_DSCP"); |
| MODULE_ALIAS("ipt_TOS"); |
| MODULE_ALIAS("ip6t_TOS"); |
| |
| static unsigned int |
| dscp_tg(struct sk_buff *skb, const struct xt_target_param *par) |
| { |
| const struct xt_DSCP_info *dinfo = par->targinfo; |
| u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT; |
| |
| if (dscp != dinfo->dscp) { |
| if (!skb_make_writable(skb, sizeof(struct iphdr))) |
| return NF_DROP; |
| |
| ipv4_change_dsfield(ip_hdr(skb), (__u8)(~XT_DSCP_MASK), |
| dinfo->dscp << XT_DSCP_SHIFT); |
| |
| } |
| return XT_CONTINUE; |
| } |
| |
| static unsigned int |
| dscp_tg6(struct sk_buff *skb, const struct xt_target_param *par) |
| { |
| const struct xt_DSCP_info *dinfo = par->targinfo; |
| u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT; |
| |
| if (dscp != dinfo->dscp) { |
| if (!skb_make_writable(skb, sizeof(struct ipv6hdr))) |
| return NF_DROP; |
| |
| ipv6_change_dsfield(ipv6_hdr(skb), (__u8)(~XT_DSCP_MASK), |
| dinfo->dscp << XT_DSCP_SHIFT); |
| } |
| return XT_CONTINUE; |
| } |
| |
| static bool |
| dscp_tg_check(const char *tablename, const void *e_void, |
| const struct xt_target *target, void *targinfo, |
| unsigned int hook_mask) |
| { |
| const u_int8_t dscp = ((struct xt_DSCP_info *)targinfo)->dscp; |
| |
| if (dscp > XT_DSCP_MAX) { |
| printk(KERN_WARNING "DSCP: dscp %x out of range\n", dscp); |
| return false; |
| } |
| return true; |
| } |
| |
| static unsigned int |
| tos_tg_v0(struct sk_buff *skb, const struct xt_target_param *par) |
| { |
| const struct ipt_tos_target_info *info = par->targinfo; |
| struct iphdr *iph = ip_hdr(skb); |
| u_int8_t oldtos; |
| |
| if ((iph->tos & IPTOS_TOS_MASK) != info->tos) { |
| 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) | info->tos; |
| csum_replace2(&iph->check, htons(oldtos), htons(iph->tos)); |
| } |
| |
| return XT_CONTINUE; |
| } |
| |
| static bool |
| tos_tg_check_v0(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 unsigned int |
| tos_tg(struct sk_buff *skb, const struct xt_target_param *par) |
| { |
| const struct xt_tos_target_info *info = par->targinfo; |
| struct iphdr *iph = ip_hdr(skb); |
| u_int8_t orig, nv; |
| |
| orig = ipv4_get_dsfield(iph); |
| nv = (orig & ~info->tos_mask) ^ info->tos_value; |
| |
| if (orig != nv) { |
| if (!skb_make_writable(skb, sizeof(struct iphdr))) |
| return NF_DROP; |
| iph = ip_hdr(skb); |
| ipv4_change_dsfield(iph, 0, nv); |
| } |
| |
| return XT_CONTINUE; |
| } |
| |
| static unsigned int |
| tos_tg6(struct sk_buff *skb, const struct xt_target_param *par) |
| { |
| const struct xt_tos_target_info *info = par->targinfo; |
| struct ipv6hdr *iph = ipv6_hdr(skb); |
| u_int8_t orig, nv; |
| |
| orig = ipv6_get_dsfield(iph); |
| nv = (orig & info->tos_mask) ^ info->tos_value; |
| |
| if (orig != nv) { |
| if (!skb_make_writable(skb, sizeof(struct iphdr))) |
| return NF_DROP; |
| iph = ipv6_hdr(skb); |
| ipv6_change_dsfield(iph, 0, nv); |
| } |
| |
| return XT_CONTINUE; |
| } |
| |
| static struct xt_target dscp_tg_reg[] __read_mostly = { |
| { |
| .name = "DSCP", |
| .family = NFPROTO_IPV4, |
| .checkentry = dscp_tg_check, |
| .target = dscp_tg, |
| .targetsize = sizeof(struct xt_DSCP_info), |
| .table = "mangle", |
| .me = THIS_MODULE, |
| }, |
| { |
| .name = "DSCP", |
| .family = NFPROTO_IPV6, |
| .checkentry = dscp_tg_check, |
| .target = dscp_tg6, |
| .targetsize = sizeof(struct xt_DSCP_info), |
| .table = "mangle", |
| .me = THIS_MODULE, |
| }, |
| { |
| .name = "TOS", |
| .revision = 0, |
| .family = NFPROTO_IPV4, |
| .table = "mangle", |
| .target = tos_tg_v0, |
| .targetsize = sizeof(struct ipt_tos_target_info), |
| .checkentry = tos_tg_check_v0, |
| .me = THIS_MODULE, |
| }, |
| { |
| .name = "TOS", |
| .revision = 1, |
| .family = NFPROTO_IPV4, |
| .table = "mangle", |
| .target = tos_tg, |
| .targetsize = sizeof(struct xt_tos_target_info), |
| .me = THIS_MODULE, |
| }, |
| { |
| .name = "TOS", |
| .revision = 1, |
| .family = NFPROTO_IPV6, |
| .table = "mangle", |
| .target = tos_tg6, |
| .targetsize = sizeof(struct xt_tos_target_info), |
| .me = THIS_MODULE, |
| }, |
| }; |
| |
| static int __init dscp_tg_init(void) |
| { |
| return xt_register_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
| } |
| |
| static void __exit dscp_tg_exit(void) |
| { |
| xt_unregister_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
| } |
| |
| module_init(dscp_tg_init); |
| module_exit(dscp_tg_exit); |