/* 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> MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); MODULE_DESCRIPTION("x_tables DSCP modification module"); MODULE_LICENSE("GPL"); MODULE_ALIAS("ipt_DSCP"); MODULE_ALIAS("ip6t_DSCP"); static unsigned int target(struct sk_buff **pskb, const struct net_device *in, const struct net_device *out, unsigned int hooknum, const struct xt_target *target, const void *targinfo) { const struct xt_DSCP_info *dinfo = targinfo; u_int8_t dscp = ipv4_get_dsfield(ip_hdr(*pskb)) >> XT_DSCP_SHIFT; if (dscp != dinfo->dscp) { if (!skb_make_writable(pskb, sizeof(struct iphdr))) return NF_DROP; ipv4_change_dsfield(ip_hdr(*pskb), (__u8)(~XT_DSCP_MASK), dinfo->dscp << XT_DSCP_SHIFT); } return XT_CONTINUE; } static unsigned int target6(struct sk_buff **pskb, const struct net_device *in, const struct net_device *out, unsigned int hooknum, const struct xt_target *target, const void *targinfo) { const struct xt_DSCP_info *dinfo = targinfo; u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(*pskb)) >> XT_DSCP_SHIFT; if (dscp != dinfo->dscp) { if (!skb_make_writable(pskb, sizeof(struct ipv6hdr))) return NF_DROP; ipv6_change_dsfield(ipv6_hdr(*pskb), (__u8)(~XT_DSCP_MASK), dinfo->dscp << XT_DSCP_SHIFT); } return XT_CONTINUE; } static int checkentry(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 0; } return 1; } static struct xt_target xt_dscp_target[] = { { .name = "DSCP", .family = AF_INET, .checkentry = checkentry, .target = target, .targetsize = sizeof(struct xt_DSCP_info), .table = "mangle", .me = THIS_MODULE, }, { .name = "DSCP", .family = AF_INET6, .checkentry = checkentry, .target = target6, .targetsize = sizeof(struct xt_DSCP_info), .table = "mangle", .me = THIS_MODULE, }, }; static int __init xt_dscp_target_init(void) { return xt_register_targets(xt_dscp_target, ARRAY_SIZE(xt_dscp_target)); } static void __exit xt_dscp_target_fini(void) { xt_unregister_targets(xt_dscp_target, ARRAY_SIZE(xt_dscp_target)); } module_init(xt_dscp_target_init); module_exit(xt_dscp_target_fini);