| | 1 | /* x_tables module for setting the IPv4/IPv6 DSCP field, Version 1.8 |
| | 2 | * |
| | 3 | * (C) 2002 by Harald Welte <laforge@netfilter.org> |
| | 4 | * based on ipt_FTOS.c (C) 2000 by Matthew G. Marsh <mgm@paktronix.com> |
| | 5 | * |
| | 6 | * This program is free software; you can redistribute it and/or modify |
| | 7 | * it under the terms of the GNU General Public License version 2 as |
| | 8 | * published by the Free Software Foundation. |
| | 9 | * |
| | 10 | * See RFC2474 for a description of the DSCP field within the IP Header. |
| | 11 | */ |
| | 12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| | 13 | #include <linux/module.h> |
| | 14 | #include <linux/skbuff.h> |
| | 15 | #include <linux/ip.h> |
| | 16 | #include <linux/ipv6.h> |
| | 17 | #include <net/dsfield.h> |
| | 18 | |
| | 19 | #include <linux/netfilter/x_tables.h> |
| | 20 | #include <linux/netfilter/xt_DSCP.h> |
| | 21 | |
| | 22 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| | 23 | MODULE_DESCRIPTION("Xtables: DSCP/TOS field modification"); |
| | 24 | MODULE_LICENSE("GPL"); |
| | 25 | MODULE_ALIAS("ipt_DSCP"); |
| | 26 | MODULE_ALIAS("ip6t_DSCP"); |
| | 27 | MODULE_ALIAS("ipt_TOS"); |
| | 28 | MODULE_ALIAS("ip6t_TOS"); |
| | 29 | |
| | 30 | static unsigned int |
| | 31 | dscp_tg(struct sk_buff *skb, const struct xt_action_param *par) |
| | 32 | { |
| | 33 | const struct xt_DSCP_info *dinfo = par->targinfo; |
| | 34 | u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT; |
| | 35 | |
| | 36 | if (dscp != dinfo->dscp) { |
| | 37 | if (!skb_make_writable(skb, sizeof(struct iphdr))) |
| | 38 | return NF_DROP; |
| | 39 | |
| | 40 | ipv4_change_dsfield(ip_hdr(skb), |
| | 41 | (__force __u8)(~XT_DSCP_MASK), |
| | 42 | dinfo->dscp << XT_DSCP_SHIFT); |
| | 43 | |
| | 44 | } |
| | 45 | return XT_CONTINUE; |
| | 46 | } |
| | 47 | |
| | 48 | static unsigned int |
| | 49 | dscp_tg6(struct sk_buff *skb, const struct xt_action_param *par) |
| | 50 | { |
| | 51 | const struct xt_DSCP_info *dinfo = par->targinfo; |
| | 52 | u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT; |
| | 53 | |
| | 54 | if (dscp != dinfo->dscp) { |
| | 55 | if (!skb_make_writable(skb, sizeof(struct ipv6hdr))) |
| | 56 | return NF_DROP; |
| | 57 | |
| | 58 | ipv6_change_dsfield(ipv6_hdr(skb), |
| | 59 | (__force __u8)(~XT_DSCP_MASK), |
| | 60 | dinfo->dscp << XT_DSCP_SHIFT); |
| | 61 | } |
| | 62 | return XT_CONTINUE; |
| | 63 | } |
| | 64 | |
| | 65 | static int dscp_tg_check(const struct xt_tgchk_param *par) |
| | 66 | { |
| | 67 | const struct xt_DSCP_info *info = par->targinfo; |
| | 68 | |
| | 69 | if (info->dscp > XT_DSCP_MAX) { |
| | 70 | pr_info("dscp %x out of range\n", info->dscp); |
| | 71 | return -EDOM; |
| | 72 | } |
| | 73 | return 0; |
| | 74 | } |
| | 75 | |
| | 76 | static unsigned int |
| | 77 | tos_tg(struct sk_buff *skb, const struct xt_action_param *par) |
| | 78 | { |
| | 79 | const struct xt_tos_target_info *info = par->targinfo; |
| | 80 | struct iphdr *iph = ip_hdr(skb); |
| | 81 | u_int8_t orig, nv; |
| | 82 | |
| | 83 | orig = ipv4_get_dsfield(iph); |
| | 84 | nv = (orig & ~info->tos_mask) ^ info->tos_value; |
| | 85 | |
| | 86 | if (orig != nv) { |
| | 87 | if (!skb_make_writable(skb, sizeof(struct iphdr))) |
| | 88 | return NF_DROP; |
| | 89 | iph = ip_hdr(skb); |
| | 90 | ipv4_change_dsfield(iph, 0, nv); |
| | 91 | } |
| | 92 | |
| | 93 | return XT_CONTINUE; |
| | 94 | } |
| | 95 | |
| | 96 | static unsigned int |
| | 97 | tos_tg6(struct sk_buff *skb, const struct xt_action_param *par) |
| | 98 | { |
| | 99 | const struct xt_tos_target_info *info = par->targinfo; |
| | 100 | struct ipv6hdr *iph = ipv6_hdr(skb); |
| | 101 | u_int8_t orig, nv; |
| | 102 | |
| | 103 | orig = ipv6_get_dsfield(iph); |
| | 104 | nv = (orig & ~info->tos_mask) ^ info->tos_value; |
| | 105 | |
| | 106 | if (orig != nv) { |
| | 107 | if (!skb_make_writable(skb, sizeof(struct iphdr))) |
| | 108 | return NF_DROP; |
| | 109 | iph = ipv6_hdr(skb); |
| | 110 | ipv6_change_dsfield(iph, 0, nv); |
| | 111 | } |
| | 112 | |
| | 113 | return XT_CONTINUE; |
| | 114 | } |
| | 115 | |
| | 116 | static struct xt_target dscp_tg_reg[] __read_mostly = { |
| | 117 | { |
| | 118 | .name = "DSCP", |
| | 119 | .family = NFPROTO_IPV4, |
| | 120 | .checkentry = dscp_tg_check, |
| | 121 | .target = dscp_tg, |
| | 122 | .targetsize = sizeof(struct xt_DSCP_info), |
| | 123 | .table = "mangle", |
| | 124 | .me = THIS_MODULE, |
| | 125 | }, |
| | 126 | { |
| | 127 | .name = "DSCP", |
| | 128 | .family = NFPROTO_IPV6, |
| | 129 | .checkentry = dscp_tg_check, |
| | 130 | .target = dscp_tg6, |
| | 131 | .targetsize = sizeof(struct xt_DSCP_info), |
| | 132 | .table = "mangle", |
| | 133 | .me = THIS_MODULE, |
| | 134 | }, |
| | 135 | { |
| | 136 | .name = "TOS", |
| | 137 | .revision = 1, |
| | 138 | .family = NFPROTO_IPV4, |
| | 139 | .table = "mangle", |
| | 140 | .target = tos_tg, |
| | 141 | .targetsize = sizeof(struct xt_tos_target_info), |
| | 142 | .me = THIS_MODULE, |
| | 143 | }, |
| | 144 | { |
| | 145 | .name = "TOS", |
| | 146 | .revision = 1, |
| | 147 | .family = NFPROTO_IPV6, |
| | 148 | .table = "mangle", |
| | 149 | .target = tos_tg6, |
| | 150 | .targetsize = sizeof(struct xt_tos_target_info), |
| | 151 | .me = THIS_MODULE, |
| | 152 | }, |
| | 153 | }; |
| | 154 | |
| | 155 | static int __init dscp_tg_init(void) |
| | 156 | { |
| | 157 | return xt_register_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
| | 158 | } |
| | 159 | |
| | 160 | static void __exit dscp_tg_exit(void) |
| | 161 | { |
| | 162 | xt_unregister_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
| | 163 | } |
| | 164 | |
| | 165 | module_init(dscp_tg_init); |
| | 166 | module_exit(dscp_tg_exit); |
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