-/* IP tables module for matching the value of the IPv4 and TCP ECN bits
- *
- * ipt_ecn.c,v 1.3 2002/05/29 15:09:00 laforge Exp
- *
- * (C) 2002 by Harald Welte <laforge@gnumonks.org>
+/* iptables module for the IPv4 and TCP ECN bits, Version 1.5
*
+ * (C) 2002 by Harald Welte <laforge@netfilter.org>
+ *
* 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
+ * it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
- */
+ *
+ * ipt_ECN.c,v 1.5 2002/08/18 19:36:51 laforge Exp
+*/
#include <linux/module.h>
#include <linux/skbuff.h>
+#include <linux/ip.h>
#include <linux/tcp.h>
+#include <net/checksum.h>
#include <linux/netfilter_ipv4/ip_tables.h>
-#include <linux/netfilter_ipv4/ipt_ecn.h>
+#include <linux/netfilter_ipv4/ipt_ECN.h>
-MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
-MODULE_DESCRIPTION("iptables ECN matching module");
MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_DESCRIPTION("iptables ECN modification module");
-static inline int match_ip(const struct sk_buff *skb,
- const struct ipt_ecn_info *einfo)
+/* set ECT codepoint from IP header.
+ * return 0 if there was an error. */
+static inline int
+set_ect_ip(struct sk_buff **pskb, const struct ipt_ECN_info *einfo)
{
- return ((skb->nh.iph->tos&IPT_ECN_IP_MASK) == einfo->ip_ect);
+ if (((*pskb)->nh.iph->tos & IPT_ECN_IP_MASK)
+ != (einfo->ip_ect & IPT_ECN_IP_MASK)) {
+ u_int16_t diffs[2];
+
+ if (!skb_ip_make_writable(pskb, sizeof(struct iphdr)))
+ return 0;
+
+ diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF;
+ (*pskb)->nh.iph->tos &= ~IPT_ECN_IP_MASK;
+ (*pskb)->nh.iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);
+ diffs[1] = htons((*pskb)->nh.iph->tos);
+ (*pskb)->nh.iph->check
+ = csum_fold(csum_partial((char *)diffs,
+ sizeof(diffs),
+ (*pskb)->nh.iph->check
+ ^0xFFFF));
+ (*pskb)->nfcache |= NFC_ALTERED;
+ }
+ return 1;
}
-static inline int match_tcp(const struct sk_buff *skb,
- const struct ipt_ecn_info *einfo,
- int *hotdrop)
+/* Return 0 if there was an error. */
+static inline int
+set_ect_tcp(struct sk_buff **pskb, const struct ipt_ECN_info *einfo, int inward)
{
struct tcphdr tcph;
+ u_int16_t diffs[2];
- /* In practice, TCP match does this, so can't fail. But let's
- be good citizens. */
- if (skb_copy_bits(skb, skb->nh.iph->ihl*4, &tcph, sizeof(tcph)) < 0) {
- *hotdrop = 0;
+ /* Not enought header? */
+ if (skb_copy_bits(*pskb, (*pskb)->nh.iph->ihl*4, &tcph, sizeof(tcph))
+ < 0)
return 0;
- }
- if (einfo->operation & IPT_ECN_OP_MATCH_ECE) {
- if (einfo->invert & IPT_ECN_OP_MATCH_ECE) {
- if (tcph.ece == 1)
- return 0;
- } else {
- if (tcph.ece == 0)
- return 0;
- }
- }
+ diffs[0] = ((u_int16_t *)&tcph)[6];
+ if (einfo->operation & IPT_ECN_OP_SET_ECE)
+ tcph.ece = einfo->proto.tcp.ece;
- if (einfo->operation & IPT_ECN_OP_MATCH_CWR) {
- if (einfo->invert & IPT_ECN_OP_MATCH_CWR) {
- if (tcph.cwr == 1)
- return 0;
- } else {
- if (tcph.cwr == 0)
+ if (einfo->operation & IPT_ECN_OP_SET_CWR)
+ tcph.cwr = einfo->proto.tcp.cwr;
+ diffs[1] = ((u_int16_t *)&tcph)[6];
+
+ /* Only mangle if it's changed. */
+ if (diffs[0] != diffs[1]) {
+ diffs[0] = diffs[0] ^ 0xFFFF;
+ if (!skb_ip_make_writable(pskb,
+ (*pskb)->nh.iph->ihl*4+sizeof(tcph)))
+ return 0;
+ if ((*pskb)->ip_summed != CHECKSUM_HW)
+ tcph.check = csum_fold(csum_partial((char *)diffs,
+ sizeof(diffs),
+ tcph.check^0xFFFF));
+ memcpy((*pskb)->data + (*pskb)->nh.iph->ihl*4,
+ &tcph, sizeof(tcph));
+ if ((*pskb)->ip_summed == CHECKSUM_HW)
+ if (skb_checksum_help(pskb, inward))
return 0;
- }
+ (*pskb)->nfcache |= NFC_ALTERED;
}
-
return 1;
}
-static int match(const struct sk_buff *skb, const struct net_device *in,
- const struct net_device *out, const void *matchinfo,
- int offset, int *hotdrop)
+static unsigned int
+target(struct sk_buff **pskb,
+ const struct net_device *in,
+ const struct net_device *out,
+ unsigned int hooknum,
+ const void *targinfo,
+ void *userinfo)
{
- const struct ipt_ecn_info *info = matchinfo;
+ const struct ipt_ECN_info *einfo = targinfo;
- if (info->operation & IPT_ECN_OP_MATCH_IP)
- if (!match_ip(skb, info))
- return 0;
+ if (einfo->operation & IPT_ECN_OP_SET_IP)
+ if (!set_ect_ip(pskb, einfo))
+ return NF_DROP;
- if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)) {
- if (skb->nh.iph->protocol != IPPROTO_TCP)
- return 0;
- if (!match_tcp(skb, info, hotdrop))
- return 0;
- }
+ if (einfo->operation & (IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR)
+ && (*pskb)->nh.iph->protocol == IPPROTO_TCP)
+ if (!set_ect_tcp(pskb, einfo, (out == NULL)))
+ return NF_DROP;
- return 1;
+ return IPT_CONTINUE;
}
-static int checkentry(const char *tablename, const struct ipt_ip *ip,
- void *matchinfo, unsigned int matchsize,
- unsigned int hook_mask)
+static int
+checkentry(const char *tablename,
+ const struct ipt_entry *e,
+ void *targinfo,
+ unsigned int targinfosize,
+ unsigned int hook_mask)
{
- const struct ipt_ecn_info *info = matchinfo;
+ const struct ipt_ECN_info *einfo = (struct ipt_ECN_info *)targinfo;
- if (matchsize != IPT_ALIGN(sizeof(struct ipt_ecn_info)))
+ if (targinfosize != IPT_ALIGN(sizeof(struct ipt_ECN_info))) {
+ printk(KERN_WARNING "ECN: targinfosize %u != %Zu\n",
+ targinfosize,
+ IPT_ALIGN(sizeof(struct ipt_ECN_info)));
return 0;
+ }
- if (info->operation & IPT_ECN_OP_MATCH_MASK)
+ if (strcmp(tablename, "mangle") != 0) {
+ printk(KERN_WARNING "ECN: can only be called from \"mangle\" table, not \"%s\"\n", tablename);
return 0;
+ }
- if (info->invert & IPT_ECN_OP_MATCH_MASK)
+ if (einfo->operation & IPT_ECN_OP_MASK) {
+ printk(KERN_WARNING "ECN: unsupported ECN operation %x\n",
+ einfo->operation);
return 0;
+ }
+ if (einfo->ip_ect & ~IPT_ECN_IP_MASK) {
+ printk(KERN_WARNING "ECN: new ECT codepoint %x out of mask\n",
+ einfo->ip_ect);
+ return 0;
+ }
- if (info->operation & (IPT_ECN_OP_MATCH_ECE|IPT_ECN_OP_MATCH_CWR)
- && ip->proto != IPPROTO_TCP) {
- printk(KERN_WARNING "ipt_ecn: can't match TCP bits in rule for"
- " non-tcp packets\n");
+ if ((einfo->operation & (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR))
+ && e->ip.proto != IPPROTO_TCP) {
+ printk(KERN_WARNING "ECN: cannot use TCP operations on a "
+ "non-tcp rule\n");
return 0;
}
return 1;
}
-static struct ipt_match ecn_match = {
- .name = "ecn",
- .match = &match,
- .checkentry = &checkentry,
+static struct ipt_target ipt_ecn_reg = {
+ .name = "ECN",
+ .target = target,
+ .checkentry = checkentry,
.me = THIS_MODULE,
};
static int __init init(void)
{
- return ipt_register_match(&ecn_match);
+ return ipt_register_target(&ipt_ecn_reg);
}
static void __exit fini(void)
{
- ipt_unregister_match(&ecn_match);
+ ipt_unregister_target(&ipt_ecn_reg);
}
module_init(init);
projects / bcm963xx.git / blobdiff