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