Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* iptables module for the IPv4 and TCP ECN bits, Version 1.5 |
| 2 | * |
| 3 | * (C) 2002 by Harald Welte <laforge@netfilter.org> |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 4 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5 | * This program is free software; you can redistribute it and/or modify |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 6 | * it under the terms of the GNU General Public License version 2 as |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | * published by the Free Software Foundation. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | */ |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 10 | #include <linux/in.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | #include <linux/module.h> |
| 12 | #include <linux/skbuff.h> |
| 13 | #include <linux/ip.h> |
Arnaldo Carvalho de Melo | c9bdd4b | 2007-03-12 20:09:15 -0300 | [diff] [blame] | 14 | #include <net/ip.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/tcp.h> |
| 16 | #include <net/checksum.h> |
| 17 | |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 18 | #include <linux/netfilter/x_tables.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 20 | #include <linux/netfilter_ipv4/ipt_ECN.h> |
| 21 | |
| 22 | MODULE_LICENSE("GPL"); |
| 23 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 24 | MODULE_DESCRIPTION("Xtables: Explicit Congestion Notification (ECN) flag modification"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | |
| 26 | /* set ECT codepoint from IP header. |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 27 | * return false if there was an error. */ |
| 28 | static inline bool |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 29 | set_ect_ip(struct sk_buff *skb, const struct ipt_ECN_info *einfo) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | { |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 31 | struct iphdr *iph = ip_hdr(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
Patrick McHardy | da878c8 | 2006-08-22 00:33:09 -0700 | [diff] [blame] | 33 | if ((iph->tos & IPT_ECN_IP_MASK) != (einfo->ip_ect & IPT_ECN_IP_MASK)) { |
Al Viro | 43bc0ca | 2006-11-14 21:43:23 -0800 | [diff] [blame] | 34 | __u8 oldtos; |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 35 | if (!skb_make_writable(skb, sizeof(struct iphdr))) |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 36 | return false; |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 37 | iph = ip_hdr(skb); |
Patrick McHardy | da878c8 | 2006-08-22 00:33:09 -0700 | [diff] [blame] | 38 | oldtos = iph->tos; |
| 39 | iph->tos &= ~IPT_ECN_IP_MASK; |
| 40 | iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK); |
Patrick McHardy | be0ea7d | 2007-11-30 01:17:11 +1100 | [diff] [blame] | 41 | csum_replace2(&iph->check, htons(oldtos), htons(iph->tos)); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 42 | } |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 43 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | } |
| 45 | |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 46 | /* Return false if there was an error. */ |
| 47 | static inline bool |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 48 | set_ect_tcp(struct sk_buff *skb, const struct ipt_ECN_info *einfo) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | { |
| 50 | struct tcphdr _tcph, *tcph; |
Al Viro | 6a19d61 | 2006-09-28 14:22:24 -0700 | [diff] [blame] | 51 | __be16 oldval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | |
André Goddard Rosa | af901ca | 2009-11-14 13:09:05 -0200 | [diff] [blame] | 53 | /* Not enough header? */ |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 54 | tcph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | if (!tcph) |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 56 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | |
Patrick McHardy | fd84132 | 2005-08-20 17:38:40 -0700 | [diff] [blame] | 58 | if ((!(einfo->operation & IPT_ECN_OP_SET_ECE) || |
| 59 | tcph->ece == einfo->proto.tcp.ece) && |
Jan Engelhardt | 7c4e36b | 2007-07-07 22:19:08 -0700 | [diff] [blame] | 60 | (!(einfo->operation & IPT_ECN_OP_SET_CWR) || |
| 61 | tcph->cwr == einfo->proto.tcp.cwr)) |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 62 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 63 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 64 | if (!skb_make_writable(skb, ip_hdrlen(skb) + sizeof(*tcph))) |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 65 | return false; |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 66 | tcph = (void *)ip_hdr(skb) + ip_hdrlen(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | |
Al Viro | 6a19d61 | 2006-09-28 14:22:24 -0700 | [diff] [blame] | 68 | oldval = ((__be16 *)tcph)[6]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | if (einfo->operation & IPT_ECN_OP_SET_ECE) |
| 70 | tcph->ece = einfo->proto.tcp.ece; |
| 71 | if (einfo->operation & IPT_ECN_OP_SET_CWR) |
| 72 | tcph->cwr = einfo->proto.tcp.cwr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | |
Patrick McHardy | be0ea7d | 2007-11-30 01:17:11 +1100 | [diff] [blame] | 74 | inet_proto_csum_replace2(&tcph->check, skb, |
Tom Herbert | 4b048d6 | 2015-08-17 13:42:25 -0700 | [diff] [blame] | 75 | oldval, ((__be16 *)tcph)[6], false); |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 76 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | } |
| 78 | |
| 79 | static unsigned int |
Jan Engelhardt | 4b560b4 | 2009-07-05 19:43:26 +0200 | [diff] [blame] | 80 | ecn_tg(struct sk_buff *skb, const struct xt_action_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | { |
Jan Engelhardt | 7eb3558 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 82 | const struct ipt_ECN_info *einfo = par->targinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | |
| 84 | if (einfo->operation & IPT_ECN_OP_SET_IP) |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 85 | if (!set_ect_ip(skb, einfo)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | return NF_DROP; |
| 87 | |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 88 | if (einfo->operation & (IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR) && |
| 89 | ip_hdr(skb)->protocol == IPPROTO_TCP) |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 90 | if (!set_ect_tcp(skb, einfo)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | return NF_DROP; |
| 92 | |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 93 | return XT_CONTINUE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | } |
| 95 | |
Jan Engelhardt | 135367b | 2010-03-19 17:16:42 +0100 | [diff] [blame] | 96 | static int ecn_tg_check(const struct xt_tgchk_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | { |
Jan Engelhardt | af5d6dc | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 98 | const struct ipt_ECN_info *einfo = par->targinfo; |
| 99 | const struct ipt_entry *e = par->entryinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | if (einfo->operation & IPT_ECN_OP_MASK) { |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 102 | pr_info("unsupported ECN operation %x\n", einfo->operation); |
Jan Engelhardt | d6b00a5 | 2010-03-25 16:34:45 +0100 | [diff] [blame] | 103 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | } |
| 105 | if (einfo->ip_ect & ~IPT_ECN_IP_MASK) { |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 106 | pr_info("new ECT codepoint %x out of mask\n", einfo->ip_ect); |
Jan Engelhardt | d6b00a5 | 2010-03-25 16:34:45 +0100 | [diff] [blame] | 107 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | } |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 109 | if ((einfo->operation & (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR)) && |
| 110 | (e->ip.proto != IPPROTO_TCP || (e->ip.invflags & XT_INV_PROTO))) { |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 111 | pr_info("cannot use TCP operations on a non-tcp rule\n"); |
Jan Engelhardt | d6b00a5 | 2010-03-25 16:34:45 +0100 | [diff] [blame] | 112 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 113 | } |
Jan Engelhardt | d6b00a5 | 2010-03-25 16:34:45 +0100 | [diff] [blame] | 114 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | } |
| 116 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 117 | static struct xt_target ecn_tg_reg __read_mostly = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | .name = "ECN", |
Jan Engelhardt | ee999d8 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 119 | .family = NFPROTO_IPV4, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 120 | .target = ecn_tg, |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 121 | .targetsize = sizeof(struct ipt_ECN_info), |
| 122 | .table = "mangle", |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 123 | .checkentry = ecn_tg_check, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | .me = THIS_MODULE, |
| 125 | }; |
| 126 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 127 | static int __init ecn_tg_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 129 | return xt_register_target(&ecn_tg_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | } |
| 131 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 132 | static void __exit ecn_tg_exit(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 134 | xt_unregister_target(&ecn_tg_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | } |
| 136 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 137 | module_init(ecn_tg_init); |
| 138 | module_exit(ecn_tg_exit); |