From: Patrick McHardy <kaber@xxxxxxxxx> References: http://www.spinics.net/lists/netfilter-devel/msg18875.html Augment xt_ecn by facilities to match on IPv6 packets' DSCP/TOS field similar to how it is already done for the IPv4 packet field. Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxx> --- net/netfilter/xt_ecn.c | 106 ++++++++++++++++++++++++++++++++++++------------ 1 files changed, 80 insertions(+), 26 deletions(-) diff --git a/net/netfilter/xt_ecn.c b/net/netfilter/xt_ecn.c index 3ebb3dc..6ccc35d 100644 --- a/net/netfilter/xt_ecn.c +++ b/net/netfilter/xt_ecn.c @@ -1,6 +1,8 @@ -/* IP tables module for matching the value of the IPv4 and TCP ECN bits +/* + * Xtables module for matching the value of the IPv4/IPv6 and TCP ECN bits * * (C) 2002 by Harald Welte <laforge@xxxxxxxxxxxx> + * (C) 2011 Patrick McHardy <kaber@xxxxxxxxx> * * 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 @@ -17,32 +19,25 @@ #include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_ecn.h> #include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv6/ip6_tables.h> MODULE_AUTHOR("Harald Welte <laforge@xxxxxxxxxxxxx>"); -MODULE_DESCRIPTION("Xtables: Explicit Congestion Notification (ECN) flag match for IPv4"); +MODULE_DESCRIPTION("Xtables: Explicit Congestion Notification (ECN) flag match"); MODULE_LICENSE("GPL"); MODULE_ALIAS("ipt_ecn"); +MODULE_ALIAS("ip6t_ecn"); -static inline bool match_ip(const struct sk_buff *skb, - const struct xt_ecn_info *einfo) -{ - return ((ip_hdr(skb)->tos & XT_ECN_IP_MASK) == einfo->ip_ect) ^ - !!(einfo->invert & XT_ECN_OP_MATCH_IP); -} - -static inline bool match_tcp(const struct sk_buff *skb, - const struct xt_ecn_info *einfo, - bool *hotdrop) +static bool match_tcp(const struct sk_buff *skb, struct xt_action_param *par) { + const struct xt_ecn_info *einfo = par->matchinfo; struct tcphdr _tcph; const struct tcphdr *th; /* In practice, TCP match does this, so can't fail. But let's * be good citizens. */ - th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph); + th = skb_header_pointer(skb, par->thoff, sizeof(_tcph), &_tcph); if (th == NULL) { - *hotdrop = false; return false; } @@ -69,7 +64,14 @@ static inline bool match_tcp(const struct sk_buff *skb, return true; } -static bool ecn_mt(const struct sk_buff *skb, struct xt_action_param *par) +static inline bool match_ip(const struct sk_buff *skb, + const struct xt_ecn_info *einfo) +{ + return ((ip_hdr(skb)->tos & XT_ECN_IP_MASK) == einfo->ip_ect) ^ + !!(einfo->invert & XT_ECN_OP_MATCH_IP); +} + +static bool ecn_mt4(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_ecn_info *info = par->matchinfo; @@ -78,14 +80,14 @@ static bool ecn_mt(const struct sk_buff *skb, struct xt_action_param *par) return false; if (info->operation & (XT_ECN_OP_MATCH_ECE | XT_ECN_OP_MATCH_CWR)) { - if (!match_tcp(skb, info, &par->hotdrop)) + if (!match_tcp(skb, par)) return false; } return true; } -static int ecn_mt_check(const struct xt_mtchk_param *par) +static int ecn_mt_check4(const struct xt_mtchk_param *par) { const struct xt_ecn_info *info = par->matchinfo; const struct ipt_ip *ip = par->entryinfo; @@ -105,23 +107,75 @@ static int ecn_mt_check(const struct xt_mtchk_param *par) return 0; } -static struct xt_match ecn_mt_reg __read_mostly = { - .name = "ecn", - .family = NFPROTO_IPV4, - .match = ecn_mt, - .matchsize = sizeof(struct xt_ecn_info), - .checkentry = ecn_mt_check, - .me = THIS_MODULE, +static inline bool match_ipv6(const struct sk_buff *skb, + const struct xt_ecn_info *einfo) +{ + return (((ipv6_hdr(skb)->flow_lbl[0] >> 4) & XT_ECN_IP_MASK) == + einfo->ip_ect) ^ + !!(einfo->invert & XT_ECN_OP_MATCH_IP); +} + +static bool ecn_mt6(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_ecn_info *info = par->matchinfo; + + if (info->operation & XT_ECN_OP_MATCH_IP && !match_ipv6(skb, info)) + return false; + + if (info->operation & (XT_ECN_OP_MATCH_ECE | XT_ECN_OP_MATCH_CWR) && + !match_tcp(skb, par)) + return false; + + return true; +} + +static int ecn_mt_check6(const struct xt_mtchk_param *par) +{ + const struct xt_ecn_info *info = par->matchinfo; + const struct ip6t_ip6 *ip = par->entryinfo; + + if (info->operation & XT_ECN_OP_MATCH_MASK) + return -EINVAL; + + if (info->invert & XT_ECN_OP_MATCH_MASK) + return -EINVAL; + + if (info->operation & (XT_ECN_OP_MATCH_ECE | XT_ECN_OP_MATCH_CWR) && + (ip->proto != IPPROTO_TCP || ip->invflags & IP6T_INV_PROTO)) { + pr_info("cannot match TCP bits in rule for non-tcp packets\n"); + return -EINVAL; + } + + return 0; +} + +static struct xt_match ecn_mt_reg[] __read_mostly = { + { + .name = "ecn", + .family = NFPROTO_IPV4, + .match = ecn_mt4, + .matchsize = sizeof(struct xt_ecn_info), + .checkentry = ecn_mt_check4, + .me = THIS_MODULE, + }, + { + .name = "ecn", + .family = NFPROTO_IPV6, + .match = ecn_mt6, + .matchsize = sizeof(struct xt_ecn_info), + .checkentry = ecn_mt_check6, + .me = THIS_MODULE, + }, }; static int __init ecn_mt_init(void) { - return xt_register_match(&ecn_mt_reg); + return xt_register_matches(ecn_mt_reg, ARRAY_SIZE(ecn_mt_reg)); } static void __exit ecn_mt_exit(void) { - xt_unregister_match(&ecn_mt_reg); + xt_unregister_matches(ecn_mt_reg, ARRAY_SIZE(ecn_mt_reg)); } module_init(ecn_mt_init); -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
