net/sched: add ACT_CSUM action to update packets checksums

diff --git a/include/linux/tc_act/Kbuild b/include/linux/tc_act/Kbuild
index 7699093..67b501c 100644
--- a/include/linux/tc_act/Kbuild
+++ b/include/linux/tc_act/Kbuild
@@ -4,3 +4,4 @@  header-y += tc_mirred.h
 header-y += tc_pedit.h
 header-y += tc_nat.h
 header-y += tc_skbedit.h
+header-y += tc_csum.h
diff --git a/include/linux/tc_act/tc_csum.h b/include/linux/tc_act/tc_csum.h
new file mode 100644
index 0000000..a047c49
--- /dev/null
+++ b/include/linux/tc_act/tc_csum.h
@@ -0,0 +1,32 @@ 
+#ifndef __LINUX_TC_CSUM_H
+#define __LINUX_TC_CSUM_H
+
+#include <linux/types.h>
+#include <linux/pkt_cls.h>
+
+#define TCA_ACT_CSUM 16
+
+enum {
+	TCA_CSUM_UNSPEC,
+	TCA_CSUM_PARMS,
+	TCA_CSUM_TM,
+	__TCA_CSUM_MAX
+};
+#define TCA_CSUM_MAX (__TCA_CSUM_MAX - 1)
+
+enum {
+	TCA_CSUM_UPDATE_FLAG_IPV4HDR = 1,
+	TCA_CSUM_UPDATE_FLAG_ICMP    = 2,
+	TCA_CSUM_UPDATE_FLAG_IGMP    = 4,
+	TCA_CSUM_UPDATE_FLAG_TCP     = 8,
+	TCA_CSUM_UPDATE_FLAG_UDP     = 16,
+	TCA_CSUM_UPDATE_FLAG_UDPLITE = 32
+};
+
+struct tc_csum {
+	tc_gen;
+
+	__u32 update_flags;
+};
+
+#endif /* __LINUX_TC_CSUM_H */
diff --git a/include/net/tc_act/tc_csum.h b/include/net/tc_act/tc_csum.h
new file mode 100644
index 0000000..9e8710b
--- /dev/null
+++ b/include/net/tc_act/tc_csum.h
@@ -0,0 +1,15 @@ 
+#ifndef __NET_TC_CSUM_H
+#define __NET_TC_CSUM_H
+
+#include <linux/types.h>
+#include <net/act_api.h>
+
+struct tcf_csum {
+	struct tcf_common common;
+
+	u32 update_flags;
+};
+#define to_tcf_csum(pc) \
+	container_of(pc,struct tcf_csum,common)
+
+#endif /* __NET_TC_CSUM_H */
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 2f691fb..522d5a9 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -518,6 +518,16 @@  config NET_ACT_SKBEDIT
 	  To compile this code as a module, choose M here: the
 	  module will be called act_skbedit.
 
+config NET_ACT_CSUM
+        tristate "Checksum Updating"
+        depends on NET_CLS_ACT
+        ---help---
+	  Say Y here to update some common checksum after some direct
+	  packet alterations.
+
+	  To compile this code as a module, choose M here: the
+	  module will be called act_csum.
+
 config NET_CLS_IND
 	bool "Incoming device classification"
 	depends on NET_CLS_U32 || NET_CLS_FW
diff --git a/net/sched/Makefile b/net/sched/Makefile
index f14e71b..960f5db 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -15,6 +15,7 @@  obj-$(CONFIG_NET_ACT_NAT)	+= act_nat.o
 obj-$(CONFIG_NET_ACT_PEDIT)	+= act_pedit.o
 obj-$(CONFIG_NET_ACT_SIMP)	+= act_simple.o
 obj-$(CONFIG_NET_ACT_SKBEDIT)	+= act_skbedit.o
+obj-$(CONFIG_NET_ACT_CSUM)	+= act_csum.o
 obj-$(CONFIG_NET_SCH_FIFO)	+= sch_fifo.o
 obj-$(CONFIG_NET_SCH_CBQ)	+= sch_cbq.o
 obj-$(CONFIG_NET_SCH_HTB)	+= sch_htb.o
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
new file mode 100644
index 0000000..6f24012
--- /dev/null
+++ b/net/sched/act_csum.c
@@ -0,0 +1,700 @@ 
+/*
+ * Checksum updating actions
+ *
+ * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+
+#include <linux/netlink.h>
+#include <net/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include <linux/skbuff.h>
+
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/icmp.h>
+#include <linux/icmpv6.h>
+#include <linux/igmp.h>
+#include <net/tcp.h>
+#include <net/udp.h>
+
+#include <net/act_api.h>
+
+#include <linux/tc_act/tc_csum.h>
+#include <net/tc_act/tc_csum.h>
+
+#define CSUM_TAB_MASK 15
+static struct tcf_common *tcf_csum_ht[CSUM_TAB_MASK + 1];
+static u32 csum_idx_gen;
+static DEFINE_RWLOCK(csum_lock);
+
+static struct tcf_hashinfo csum_hash_info = {
+	.htab	=	tcf_csum_ht,
+	.hmask	=	CSUM_TAB_MASK,
+	.lock	=	&csum_lock,
+};
+
+static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
+	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
+};
+
+static int tcf_csum_init(struct nlattr *nla, struct nlattr *est,
+			 struct tc_action *a, int ovr, int bind)
+{
+	struct nlattr *tb[TCA_CSUM_MAX + 1];
+	struct tc_csum *parm;
+	struct tcf_common *pc;
+	struct tcf_csum *p;
+	int ret = 0, err;
+
+	if (nla == NULL)
+		return -EINVAL;
+
+	err = nla_parse_nested(tb, TCA_CSUM_MAX, nla,csum_policy);
+	if (err < 0)
+		return err;
+
+	if (tb[TCA_CSUM_PARMS] == NULL)
+		return -EINVAL;
+	parm = nla_data(tb[TCA_CSUM_PARMS]);
+
+	pc = tcf_hash_check(parm->index, a, bind, &csum_hash_info);
+	if (!pc) {
+		pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind, &csum_idx_gen, &csum_hash_info);
+		if (IS_ERR(pc))
+			return PTR_ERR(pc);
+		p = to_tcf_csum(pc);
+		ret = ACT_P_CREATED;
+	} else {
+		p = to_tcf_csum(pc);
+		if (!ovr) {
+			tcf_hash_release(pc, bind, &csum_hash_info);
+			return -EEXIST;
+		}
+	}
+
+	spin_lock_bh(&p->tcf_lock);
+	p->tcf_action = parm->action;
+	p->update_flags = parm->update_flags;
+	spin_unlock_bh(&p->tcf_lock);
+
+	if (ret == ACT_P_CREATED)
+		tcf_hash_insert(pc, &csum_hash_info);
+
+	return ret;
+}
+
+static int tcf_csum_cleanup(struct tc_action *a, int bind)
+{
+	struct tcf_csum *p = a->priv;
+	return tcf_hash_release(&p->common, bind, &csum_hash_info);
+}
+
+static int tcf_csum_ipv4_icmp(struct sk_buff *skb, struct iphdr *iph,
+			      unsigned int ihl, unsigned int ipl)
+{
+	struct icmphdr *icmph;
+	int hl;
+	int ntkoff;
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = ihl + sizeof(*icmph);
+
+	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
+	    (skb_cloned(skb) &&
+	     !skb_clone_writable(skb, hl + ntkoff) &&
+	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		goto fail;
+
+	icmph = (void *)(skb_network_header(skb) + ihl);
+
+	icmph->checksum = 0;
+	skb->csum = csum_partial(icmph, ipl - ihl, 0);
+	icmph->checksum = csum_fold(skb->csum);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv4_igmp(struct sk_buff *skb, struct iphdr *iph,
+			      unsigned int ihl, unsigned int ipl)
+{
+	struct igmphdr *igmph;
+	int hl;
+	int ntkoff;
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = ihl + sizeof(*igmph);
+
+	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
+	    (skb_cloned(skb) &&
+	     !skb_clone_writable(skb, hl + ntkoff) &&
+	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		goto fail;
+
+	igmph = (void *)(skb_network_header(skb) + ihl);
+
+	igmph->csum = 0;
+	skb->csum = csum_partial(igmph, ipl - ihl, 0);
+	igmph->csum = csum_fold(skb->csum);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv6_icmp(struct sk_buff *skb, struct ipv6hdr *ip6h,
+			      unsigned int ihl, unsigned int ipl)
+{
+	struct icmp6hdr *icmp6h;
+	int hl;
+	int ntkoff;
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = ihl + sizeof(*icmp6h);
+
+	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
+	    (skb_cloned(skb) &&
+	     !skb_clone_writable(skb, hl + ntkoff) &&
+	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		goto fail;
+
+	icmp6h = (void *)(skb_network_header(skb) + ihl);
+
+	icmp6h->icmp6_cksum = 0;
+	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
+	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+					      ipl - ihl, IPPROTO_ICMPV6,
+					      skb->csum);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv4_tcp(struct sk_buff *skb, struct iphdr *iph,
+			     unsigned int ihl, unsigned int ipl)
+{
+	struct tcphdr *tcph;
+	int hl;
+	int ntkoff;
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = ihl + sizeof(*tcph);
+
+	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
+	    (skb_cloned(skb) &&
+	     !skb_clone_writable(skb, hl + ntkoff) &&
+	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		goto fail;
+
+	tcph = (void *)(skb_network_header(skb) + ihl);
+
+	tcph->check = 0;
+	skb->csum = csum_partial(tcph, ipl - ihl, 0);
+	tcph->check = tcp_v4_check(ipl - ihl,
+				   iph->saddr, iph->daddr, skb->csum);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv6_tcp(struct sk_buff *skb, struct ipv6hdr *ip6h,
+			     unsigned int ihl, unsigned int ipl)
+{
+	struct tcphdr *tcph;
+	int hl;
+	int ntkoff;
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = ihl + sizeof(*tcph);
+
+	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
+	    (skb_cloned(skb) &&
+	     !skb_clone_writable(skb, hl + ntkoff) &&
+	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		goto fail;
+
+	tcph = (void *)(skb_network_header(skb) + ihl);
+
+	tcph->check = 0;
+	skb->csum = csum_partial(tcph, ipl - ihl, 0);
+	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
+				      ipl - ihl, IPPROTO_TCP,
+				      skb->csum);
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv4_udp(struct sk_buff *skb, struct iphdr *iph,
+			     unsigned int ihl, unsigned int ipl, int udplite)
+{
+	struct udphdr *udph;
+	int hl;
+	int ntkoff;
+	u16 ul;
+
+	/* Support both UDP and UDPLITE checksum algorithms,
+	 * Don't use udph->len to get the real length without any protocol check,
+	 * UDPLITE uses udph->len for another thing,
+	 * Use iph->tot_len, or just ipl.
+	 */
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = ihl + sizeof(*udph);
+
+	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
+	    (skb_cloned(skb) &&
+	     !skb_clone_writable(skb, hl + ntkoff) &&
+	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		goto fail;
+
+	udph = (void *)(skb_network_header(skb) + ihl);
+	ul = ntohs(udph->len);
+
+	if (udplite || udph->check) {
+
+		udph->check = 0;
+
+		if (udplite) {
+			if (ul == 0)
+				skb->csum = csum_partial(udph, ipl - ihl, 0);
+
+			else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
+				skb->csum = csum_partial(udph, ul, 0);
+
+			else
+				goto ignore_obscure_skb;
+		} else {
+			if (ul != ipl - ihl)
+				goto ignore_obscure_skb;
+
+			skb->csum = csum_partial(udph, ul, 0);
+		}
+
+		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
+						ul, iph->protocol,
+						skb->csum);
+
+		if (!udph->check)
+			udph->check = CSUM_MANGLED_0;
+	}
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+ignore_obscure_skb:
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv6_udp(struct sk_buff *skb, struct ipv6hdr *ip6h,
+			     unsigned int ihl, unsigned int ipl, int udplite)
+{
+	struct udphdr *udph;
+	int hl;
+	int ntkoff;
+	u16 ul;
+
+	/* Support both UDP and UDPLITE checksum algorithms,
+	 * Don't use udph->len to get the real length without any protocol check,
+	 * UDPLITE uses udph->len for another thing,
+	 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
+	 */
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = ihl + sizeof(*udph);
+
+	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
+	    (skb_cloned(skb) &&
+	     !skb_clone_writable(skb, hl + ntkoff) &&
+	     pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
+		goto fail;
+
+	udph = (void *)(skb_network_header(skb) + ihl);
+	ul = ntohs(udph->len);
+
+	udph->check = 0;
+
+	if (udplite) {
+		if (ul == 0)
+			skb->csum = csum_partial(udph, ipl - ihl, 0);
+
+		else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
+			skb->csum = csum_partial(udph, ul, 0);
+
+		else
+			goto ignore_obscure_skb;
+	} else {
+		if (ul != ipl - ihl)
+			goto ignore_obscure_skb;
+
+		skb->csum = csum_partial(udph, ul, 0);
+	}
+
+	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
+				      udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
+				      skb->csum);
+
+	if (!udph->check)
+		udph->check = CSUM_MANGLED_0;
+
+	skb->ip_summed = CHECKSUM_NONE;
+
+ignore_obscure_skb:
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
+{
+	struct iphdr *iph;
+	int ntkoff;
+
+	ntkoff = skb_network_offset(skb);
+
+	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
+		goto fail;
+
+	iph = ip_hdr(skb);
+
+	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
+	case IPPROTO_ICMP:
+	{
+		if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
+			if (!tcf_csum_ipv4_icmp(skb, iph,
+						iph->ihl * 4, ntohs(iph->tot_len)))
+				goto fail;
+		break;
+	}
+	case IPPROTO_IGMP:
+	{
+		if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
+			if (!tcf_csum_ipv4_igmp(skb, iph,
+						iph->ihl * 4, ntohs(iph->tot_len)))
+				goto fail;
+		break;
+	}
+	case IPPROTO_TCP:
+	{
+		if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
+			if (!tcf_csum_ipv4_tcp(skb, iph,
+					       iph->ihl * 4, ntohs(iph->tot_len)))
+				goto fail;
+		break;
+	}
+	case IPPROTO_UDP:
+	{
+		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
+			if (!tcf_csum_ipv4_udp(skb, iph,
+					       iph->ihl * 4, ntohs(iph->tot_len), 0))
+				goto fail;
+		break;
+	}
+	case IPPROTO_UDPLITE:
+	{
+		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
+			if (!tcf_csum_ipv4_udp(skb, iph,
+					       iph->ihl * 4, ntohs(iph->tot_len), 1))
+				goto fail;
+		break;
+	}
+	default:
+		break;
+	}
+
+	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
+		if (skb_cloned(skb) &&
+		    !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
+		    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+			goto fail;
+
+		ip_send_check(iph);
+	}
+
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
+				  unsigned int ixhl, unsigned int *pl)
+{
+	int off, len, optlen;
+	unsigned char *xh = (void *)ip6xh;
+
+	off = sizeof(*ip6xh);
+	len = ixhl - off;
+
+	while (len > 0) {
+		switch (xh[off])
+		{
+		case IPV6_TLV_PAD0:
+			optlen = 1;
+			break;
+		case IPV6_TLV_JUMBO:
+			optlen = xh[off + 1] + 2;
+			if (xh[off + 1] != 4 || (off & 3) != 2)
+				/* wrong jumbo option length/alignment */
+				goto fail;
+			*pl = ntohl(*(__be32 *)(xh + off + 2));
+			goto done;
+		default:
+			optlen = xh[off + 1] + 2;
+			if (optlen > len)
+				goto ignore;
+			break;
+		}
+		off += optlen;
+		len -= optlen;
+	}
+
+done:
+ignore:
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
+{
+	struct ipv6hdr *ip6h;
+	struct ipv6_opt_hdr *ip6xh;
+	unsigned int hl, ixhl;
+	unsigned int pl;
+	int ntkoff;
+	u8 nexthdr;
+
+	ntkoff = skb_network_offset(skb);
+
+	hl = sizeof(*ip6h);
+
+	if (!pskb_may_pull(skb, hl + ntkoff))
+		goto fail;
+
+	ip6h = ipv6_hdr(skb);
+
+	pl = ntohs(ip6h->payload_len);
+	nexthdr = ip6h->nexthdr;
+
+	do {
+		switch (nexthdr) {
+		case NEXTHDR_FRAGMENT:
+			goto ignore_skb;
+		case NEXTHDR_ROUTING:
+		case NEXTHDR_HOP:
+		case NEXTHDR_DEST:
+		{
+			if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
+				goto fail;
+			ip6xh = (void *)(skb_network_header(skb) + hl);
+			ixhl = ipv6_optlen(ip6xh);
+			if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
+				goto fail;
+			if ((nexthdr == NEXTHDR_HOP) &&
+			    !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
+				goto fail;
+			nexthdr = ip6xh->nexthdr;
+			hl += ixhl;
+			break;
+		}
+		case IPPROTO_ICMPV6:
+		{
+			if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
+				if (!tcf_csum_ipv6_icmp(skb, ip6h,
+							hl, pl + sizeof(*ip6h)))
+					goto fail;
+			goto done;
+		}
+		case IPPROTO_TCP:
+		{
+			if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
+				if (!tcf_csum_ipv6_tcp(skb, ip6h,
+						       hl, pl + sizeof(*ip6h)))
+					goto fail;
+			goto done;
+		}
+		case IPPROTO_UDP:
+		{
+			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
+				if (!tcf_csum_ipv6_udp(skb, ip6h,
+						       hl, pl + sizeof(*ip6h), 0))
+					goto fail;
+			goto done;
+		}
+		case IPPROTO_UDPLITE:
+		{
+			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
+				if (!tcf_csum_ipv6_udp(skb, ip6h,
+						       hl, pl + sizeof(*ip6h), 1))
+					goto fail;
+			goto done;
+		}
+		default:
+			goto ignore_skb;
+		}
+	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
+
+done:
+ignore_skb:
+	return 1;
+
+fail:
+	return 0;
+}
+
+static int tcf_csum(struct sk_buff *skb,
+		    struct tc_action *a, struct tcf_result *res)
+{
+	struct tcf_csum *p = a->priv;
+	int action;
+	u32 update_flags;
+
+	spin_lock(&p->tcf_lock);
+	p->tcf_tm.lastuse = jiffies;
+	p->tcf_bstats.bytes += qdisc_pkt_len(skb);
+	p->tcf_bstats.packets++;
+	action = p->tcf_action;
+	update_flags = p->update_flags;
+	spin_unlock(&p->tcf_lock);
+
+	if (unlikely(action == TC_ACT_SHOT))
+		goto drop;
+
+	switch (skb->protocol) {
+	case cpu_to_be16(ETH_P_IP):
+	{
+		if (!tcf_csum_ipv4(skb, update_flags))
+			goto drop;
+		break;
+	}
+	case cpu_to_be16(ETH_P_IPV6):
+	{
+		if (!tcf_csum_ipv6(skb, update_flags))
+			goto drop;
+		break;
+	}
+	default:
+		break;
+	}
+
+	return action;
+
+drop:
+	spin_lock(&p->tcf_lock);
+	p->tcf_qstats.drops++;
+	spin_unlock(&p->tcf_lock);
+	return TC_ACT_SHOT;
+}
+
+static int tcf_csum_dump(struct sk_buff *skb,
+			 struct tc_action *a, int bind, int ref)
+{
+	unsigned char *b = skb_tail_pointer(skb);
+	struct tcf_csum *p = a->priv;
+	struct tc_csum *opt;
+	struct tcf_t t;
+	int s;
+
+	s = sizeof(*opt);
+
+	/* netlink spinlocks held above us - must use ATOMIC */
+	opt = kzalloc(s, GFP_ATOMIC);
+	if (unlikely(!opt))
+		return -ENOBUFS;
+
+	opt->update_flags = p->update_flags;
+
+	opt->index = p->tcf_index;
+	opt->action = p->tcf_action;
+	opt->refcnt = p->tcf_refcnt - ref;
+	opt->bindcnt = p->tcf_bindcnt - bind;
+
+	NLA_PUT(skb,TCA_CSUM_PARMS,s,opt);
+	t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
+	t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
+	t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
+	NLA_PUT(skb,TCA_CSUM_TM,sizeof(t),&t);
+
+	kfree(opt);
+
+	return skb->len;
+
+nla_put_failure:
+	nlmsg_trim(skb, b);
+	kfree(opt);
+	return -1;
+}
+
+static struct tc_action_ops act_csum_ops = {
+	.kind		=	"csum",
+	.hinfo		=	&csum_hash_info,
+	.type		=	TCA_ACT_CSUM,
+	.capab		=	TCA_CAP_NONE,
+	.owner		=	THIS_MODULE,
+	.act		=	tcf_csum,
+	.dump		=	tcf_csum_dump,
+	.cleanup	=	tcf_csum_cleanup,
+	.lookup		=	tcf_hash_search,
+	.init		=	tcf_csum_init,
+	.walk		=	tcf_generic_walker
+};
+
+MODULE_DESCRIPTION("Checksum updating actions");
+MODULE_LICENSE("GPL");
+
+static int __init csum_init_module(void)
+{
+	return tcf_register_action(&act_csum_ops);
+}
+
+static void __exit csum_cleanup_module(void)
+{
+	tcf_unregister_action(&act_csum_ops);
+}
+
+module_init(csum_init_module);
+module_exit(csum_cleanup_module);