Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / net / ipv4 / netfilter / ipt_ECN.c

diff --git a/kernel/net/ipv4/netfilter/ipt_ECN.c b/kernel/net/ipv4/netfilter/ipt_ECN.c
new file mode 100644 (file)
index 0000000..4bf3dc4
--- /dev/null
+++ b/kernel/net/ipv4/netfilter/ipt_ECN.c
@@ -0,0 +1,138 @@
+/* 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
+ * published by the Free Software Foundation.
+*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/in.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <net/ip.h>
+#include <linux/tcp.h>
+#include <net/checksum.h>
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_ECN.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_DESCRIPTION("Xtables: Explicit Congestion Notification (ECN) flag modification");
+
+/* set ECT codepoint from IP header.
+ *     return false if there was an error. */
+static inline bool
+set_ect_ip(struct sk_buff *skb, const struct ipt_ECN_info *einfo)
+{
+       struct iphdr *iph = ip_hdr(skb);
+
+       if ((iph->tos & IPT_ECN_IP_MASK) != (einfo->ip_ect & IPT_ECN_IP_MASK)) {
+               __u8 oldtos;
+               if (!skb_make_writable(skb, sizeof(struct iphdr)))
+                       return false;
+               iph = ip_hdr(skb);
+               oldtos = iph->tos;
+               iph->tos &= ~IPT_ECN_IP_MASK;
+               iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);
+               csum_replace2(&iph->check, htons(oldtos), htons(iph->tos));
+       }
+       return true;
+}
+
+/* Return false if there was an error. */
+static inline bool
+set_ect_tcp(struct sk_buff *skb, const struct ipt_ECN_info *einfo)
+{
+       struct tcphdr _tcph, *tcph;
+       __be16 oldval;
+
+       /* Not enough header? */
+       tcph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
+       if (!tcph)
+               return false;
+
+       if ((!(einfo->operation & IPT_ECN_OP_SET_ECE) ||
+            tcph->ece == einfo->proto.tcp.ece) &&
+           (!(einfo->operation & IPT_ECN_OP_SET_CWR) ||
+            tcph->cwr == einfo->proto.tcp.cwr))
+               return true;
+
+       if (!skb_make_writable(skb, ip_hdrlen(skb) + sizeof(*tcph)))
+               return false;
+       tcph = (void *)ip_hdr(skb) + ip_hdrlen(skb);
+
+       oldval = ((__be16 *)tcph)[6];
+       if (einfo->operation & IPT_ECN_OP_SET_ECE)
+               tcph->ece = einfo->proto.tcp.ece;
+       if (einfo->operation & IPT_ECN_OP_SET_CWR)
+               tcph->cwr = einfo->proto.tcp.cwr;
+
+       inet_proto_csum_replace2(&tcph->check, skb,
+                                oldval, ((__be16 *)tcph)[6], 0);
+       return true;
+}
+
+static unsigned int
+ecn_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+       const struct ipt_ECN_info *einfo = par->targinfo;
+
+       if (einfo->operation & IPT_ECN_OP_SET_IP)
+               if (!set_ect_ip(skb, einfo))
+                       return NF_DROP;
+
+       if (einfo->operation & (IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR) &&
+           ip_hdr(skb)->protocol == IPPROTO_TCP)
+               if (!set_ect_tcp(skb, einfo))
+                       return NF_DROP;
+
+       return XT_CONTINUE;
+}
+
+static int ecn_tg_check(const struct xt_tgchk_param *par)
+{
+       const struct ipt_ECN_info *einfo = par->targinfo;
+       const struct ipt_entry *e = par->entryinfo;
+
+       if (einfo->operation & IPT_ECN_OP_MASK) {
+               pr_info("unsupported ECN operation %x\n", einfo->operation);
+               return -EINVAL;
+       }
+       if (einfo->ip_ect & ~IPT_ECN_IP_MASK) {
+               pr_info("new ECT codepoint %x out of mask\n", einfo->ip_ect);
+               return -EINVAL;
+       }
+       if ((einfo->operation & (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR)) &&
+           (e->ip.proto != IPPROTO_TCP || (e->ip.invflags & XT_INV_PROTO))) {
+               pr_info("cannot use TCP operations on a non-tcp rule\n");
+               return -EINVAL;
+       }
+       return 0;
+}
+
+static struct xt_target ecn_tg_reg __read_mostly = {
+       .name           = "ECN",
+       .family         = NFPROTO_IPV4,
+       .target         = ecn_tg,
+       .targetsize     = sizeof(struct ipt_ECN_info),
+       .table          = "mangle",
+       .checkentry     = ecn_tg_check,
+       .me             = THIS_MODULE,
+};
+
+static int __init ecn_tg_init(void)
+{
+       return xt_register_target(&ecn_tg_reg);
+}
+
+static void __exit ecn_tg_exit(void)
+{
+       xt_unregister_target(&ecn_tg_reg);
+}
+
+module_init(ecn_tg_init);
+module_exit(ecn_tg_exit);