diff options
Diffstat (limited to 'net/netfilter/xt_DSCP.c')
| -rw-r--r-- | net/netfilter/xt_DSCP.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/net/netfilter/xt_DSCP.c b/net/netfilter/xt_DSCP.c new file mode 100644 index 000000000..cfa44515a --- /dev/null +++ b/net/netfilter/xt_DSCP.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* 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> + * + * See RFC2474 for a description of the DSCP field within the IP Header. +*/ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#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("Xtables: DSCP/TOS field modification"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("ipt_DSCP"); +MODULE_ALIAS("ip6t_DSCP"); +MODULE_ALIAS("ipt_TOS"); +MODULE_ALIAS("ip6t_TOS"); + +#define XT_DSCP_ECN_MASK 3u + +static unsigned int +dscp_tg(struct sk_buff *skb, const struct xt_action_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_ensure_writable(skb, sizeof(struct iphdr))) + return NF_DROP; + + ipv4_change_dsfield(ip_hdr(skb), XT_DSCP_ECN_MASK, + dinfo->dscp << XT_DSCP_SHIFT); + + } + return XT_CONTINUE; +} + +static unsigned int +dscp_tg6(struct sk_buff *skb, const struct xt_action_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_ensure_writable(skb, sizeof(struct ipv6hdr))) + return NF_DROP; + + ipv6_change_dsfield(ipv6_hdr(skb), XT_DSCP_ECN_MASK, + dinfo->dscp << XT_DSCP_SHIFT); + } + return XT_CONTINUE; +} + +static int dscp_tg_check(const struct xt_tgchk_param *par) +{ + const struct xt_DSCP_info *info = par->targinfo; + + if (info->dscp > XT_DSCP_MAX) + return -EDOM; + return 0; +} + +static unsigned int +tos_tg(struct sk_buff *skb, const struct xt_action_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_ensure_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_action_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_ensure_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 = 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); |