net/openvswitch/actions.c - maze/linux - Git at Google

 /*
  * Copyright (c) 2007-2012 Nicira, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of version 2 of the GNU General Public
  * License as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  * 02110-1301, USA
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/skbuff.h>
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/openvswitch.h>
 #include <linux/tcp.h>
 #include <linux/udp.h>
 #include <linux/in6.h>
 #include <linux/if_arp.h>
 #include <linux/if_vlan.h>
 #include <net/ip.h>
 #include <net/ipv6.h>
 #include <net/checksum.h>
 #include <net/dsfield.h>

 #include "datapath.h"
 #include "vport.h"

 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			const struct nlattr *attr, int len, bool keep_skb);

 static int make_writable(struct sk_buff *skb, int write_len)
 {
 	if (!skb_cloned(skb) || skb_clone_writable(skb, write_len))
 		return 0;

 	return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
 }

 /* remove VLAN header from packet and update csum accordingly. */
 static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
 {
 	struct vlan_hdr *vhdr;
 	int err;

 	err = make_writable(skb, VLAN_ETH_HLEN);
 	if (unlikely(err))
 		return err;

 	if (skb->ip_summed == CHECKSUM_COMPLETE)
 		skb->csum = csum_sub(skb->csum, csum_partial(skb->data
 					+ (2 * ETH_ALEN), VLAN_HLEN, 0));

 	vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
 	*current_tci = vhdr->h_vlan_TCI;

 	memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
 	__skb_pull(skb, VLAN_HLEN);

 	vlan_set_encap_proto(skb, vhdr);
 	skb->mac_header += VLAN_HLEN;
 	skb_reset_mac_len(skb);

 	return 0;
 }

 static int pop_vlan(struct sk_buff *skb)
 {
 	__be16 tci;
 	int err;

 	if (likely(vlan_tx_tag_present(skb))) {
 		skb->vlan_tci = 0;
 	} else {
 		if (unlikely(skb->protocol != htons(ETH_P_8021Q) ||
 			     skb->len < VLAN_ETH_HLEN))
 			return 0;

 		err = __pop_vlan_tci(skb, &tci);
 		if (err)
 			return err;
 	}
 	/* move next vlan tag to hw accel tag */
 	if (likely(skb->protocol != htons(ETH_P_8021Q) ||
 		   skb->len < VLAN_ETH_HLEN))
 		return 0;

 	err = __pop_vlan_tci(skb, &tci);
 	if (unlikely(err))
 		return err;

 	__vlan_hwaccel_put_tag(skb, ntohs(tci));
 	return 0;
 }

 static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vlan)
 {
 	if (unlikely(vlan_tx_tag_present(skb))) {
 		u16 current_tag;

 		/* push down current VLAN tag */
 		current_tag = vlan_tx_tag_get(skb);

 		if (!__vlan_put_tag(skb, current_tag))
 			return -ENOMEM;

 		if (skb->ip_summed == CHECKSUM_COMPLETE)
 			skb->csum = csum_add(skb->csum, csum_partial(skb->data
 					+ (2 * ETH_ALEN), VLAN_HLEN, 0));

 	}
 	__vlan_hwaccel_put_tag(skb, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
 	return 0;
 }

 static int set_eth_addr(struct sk_buff *skb,
 			const struct ovs_key_ethernet *eth_key)
 {
 	int err;
 	err = make_writable(skb, ETH_HLEN);
 	if (unlikely(err))
 		return err;

 	memcpy(eth_hdr(skb)->h_source, eth_key->eth_src, ETH_ALEN);
 	memcpy(eth_hdr(skb)->h_dest, eth_key->eth_dst, ETH_ALEN);

 	return 0;
 }

 static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
 				__be32 *addr, __be32 new_addr)
 {
 	int transport_len = skb->len - skb_transport_offset(skb);

 	if (nh->protocol == IPPROTO_TCP) {
 		if (likely(transport_len >= sizeof(struct tcphdr)))
 			inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
 						 *addr, new_addr, 1);
 	} else if (nh->protocol == IPPROTO_UDP) {
 		if (likely(transport_len >= sizeof(struct udphdr))) {
 			struct udphdr *uh = udp_hdr(skb);

 			if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 				inet_proto_csum_replace4(&uh->check, skb,
 							 *addr, new_addr, 1);
 				if (!uh->check)
 					uh->check = CSUM_MANGLED_0;
 			}
 		}
 	}

 	csum_replace4(&nh->check, *addr, new_addr);
 	skb->rxhash = 0;
 	*addr = new_addr;
 }

 static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
 				 __be32 addr[4], const __be32 new_addr[4])
 {
 	int transport_len = skb->len - skb_transport_offset(skb);

 	if (l4_proto == IPPROTO_TCP) {
 		if (likely(transport_len >= sizeof(struct tcphdr)))
 			inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,
 						  addr, new_addr, 1);
 	} else if (l4_proto == IPPROTO_UDP) {
 		if (likely(transport_len >= sizeof(struct udphdr))) {
 			struct udphdr *uh = udp_hdr(skb);

 			if (uh->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 				inet_proto_csum_replace16(&uh->check, skb,
 							  addr, new_addr, 1);
 				if (!uh->check)
 					uh->check = CSUM_MANGLED_0;
 			}
 		}
 	}
 }

 static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
 			  __be32 addr[4], const __be32 new_addr[4],
 			  bool recalculate_csum)
 {
 	if (recalculate_csum)
 		update_ipv6_checksum(skb, l4_proto, addr, new_addr);

 	skb->rxhash = 0;
 	memcpy(addr, new_addr, sizeof(__be32[4]));
 }

 static void set_ipv6_tc(struct ipv6hdr *nh, u8 tc)
 {
 	nh->priority = tc >> 4;
 	nh->flow_lbl[0] = (nh->flow_lbl[0] & 0x0F) | ((tc & 0x0F) << 4);
 }

 static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl)
 {
 	nh->flow_lbl[0] = (nh->flow_lbl[0] & 0xF0) | (fl & 0x000F0000) >> 16;
 	nh->flow_lbl[1] = (fl & 0x0000FF00) >> 8;
 	nh->flow_lbl[2] = fl & 0x000000FF;
 }

 static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
 {
 	csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
 	nh->ttl = new_ttl;
 }

 static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
 {
 	struct iphdr *nh;
 	int err;

 	err = make_writable(skb, skb_network_offset(skb) +
 				 sizeof(struct iphdr));
 	if (unlikely(err))
 		return err;

 	nh = ip_hdr(skb);

 	if (ipv4_key->ipv4_src != nh->saddr)
 		set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);

 	if (ipv4_key->ipv4_dst != nh->daddr)
 		set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);

 	if (ipv4_key->ipv4_tos != nh->tos)
 		ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);

 	if (ipv4_key->ipv4_ttl != nh->ttl)
 		set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);

 	return 0;
 }

 static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
 {
 	struct ipv6hdr *nh;
 	int err;
 	__be32 *saddr;
 	__be32 *daddr;

 	err = make_writable(skb, skb_network_offset(skb) +
 			    sizeof(struct ipv6hdr));
 	if (unlikely(err))
 		return err;

 	nh = ipv6_hdr(skb);
 	saddr = (__be32 *)&nh->saddr;
 	daddr = (__be32 *)&nh->daddr;

 	if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src)))
 		set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
 			      ipv6_key->ipv6_src, true);

 	if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
 		unsigned int offset = 0;
 		int flags = IP6_FH_F_SKIP_RH;
 		bool recalc_csum = true;

 		if (ipv6_ext_hdr(nh->nexthdr))
 			recalc_csum = ipv6_find_hdr(skb, &offset,
 						    NEXTHDR_ROUTING, NULL,
 						    &flags) != NEXTHDR_ROUTING;

 		set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
 			      ipv6_key->ipv6_dst, recalc_csum);
 	}

 	set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
 	set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
 	nh->hop_limit = ipv6_key->ipv6_hlimit;

 	return 0;
 }

 /* Must follow make_writable() since that can move the skb data. */
 static void set_tp_port(struct sk_buff *skb, __be16 *port,
 			 __be16 new_port, __sum16 *check)
 {
 	inet_proto_csum_replace2(check, skb, *port, new_port, 0);
 	*port = new_port;
 	skb->rxhash = 0;
 }

 static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port)
 {
 	struct udphdr *uh = udp_hdr(skb);

 	if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
 		set_tp_port(skb, port, new_port, &uh->check);

 		if (!uh->check)
 			uh->check = CSUM_MANGLED_0;
 	} else {
 		*port = new_port;
 		skb->rxhash = 0;
 	}
 }

 static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
 {
 	struct udphdr *uh;
 	int err;

 	err = make_writable(skb, skb_transport_offset(skb) +
 				 sizeof(struct udphdr));
 	if (unlikely(err))
 		return err;

 	uh = udp_hdr(skb);
 	if (udp_port_key->udp_src != uh->source)
 		set_udp_port(skb, &uh->source, udp_port_key->udp_src);

 	if (udp_port_key->udp_dst != uh->dest)
 		set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);

 	return 0;
 }

 static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
 {
 	struct tcphdr *th;
 	int err;

 	err = make_writable(skb, skb_transport_offset(skb) +
 				 sizeof(struct tcphdr));
 	if (unlikely(err))
 		return err;

 	th = tcp_hdr(skb);
 	if (tcp_port_key->tcp_src != th->source)
 		set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);

 	if (tcp_port_key->tcp_dst != th->dest)
 		set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);

 	return 0;
 }

 static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
 {
 	struct vport *vport;

 	if (unlikely(!skb))
 		return -ENOMEM;

 	vport = ovs_vport_rcu(dp, out_port);
 	if (unlikely(!vport)) {
 		kfree_skb(skb);
 		return -ENODEV;
 	}

 	ovs_vport_send(vport, skb);
 	return 0;
 }

 static int output_userspace(struct datapath *dp, struct sk_buff *skb,
 			    const struct nlattr *attr)
 {
 	struct dp_upcall_info upcall;
 	const struct nlattr *a;
 	int rem;

 	upcall.cmd = OVS_PACKET_CMD_ACTION;
 	upcall.key = &OVS_CB(skb)->flow->key;
 	upcall.userdata = NULL;
 	upcall.portid = 0;

 	for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 		 a = nla_next(a, &rem)) {
 		switch (nla_type(a)) {
 		case OVS_USERSPACE_ATTR_USERDATA:
 			upcall.userdata = a;
 			break;

 		case OVS_USERSPACE_ATTR_PID:
 			upcall.portid = nla_get_u32(a);
 			break;
 		}
 	}

 	return ovs_dp_upcall(dp, skb, &upcall);
 }

 static int sample(struct datapath *dp, struct sk_buff *skb,
 		  const struct nlattr *attr)
 {
 	const struct nlattr *acts_list = NULL;
 	const struct nlattr *a;
 	int rem;

 	for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
 		 a = nla_next(a, &rem)) {
 		switch (nla_type(a)) {
 		case OVS_SAMPLE_ATTR_PROBABILITY:
 			if (net_random() >= nla_get_u32(a))
 				return 0;
 			break;

 		case OVS_SAMPLE_ATTR_ACTIONS:
 			acts_list = a;
 			break;
 		}
 	}

 	return do_execute_actions(dp, skb, nla_data(acts_list),
 						 nla_len(acts_list), true);
 }

 static int execute_set_action(struct sk_buff *skb,
 				 const struct nlattr *nested_attr)
 {
 	int err = 0;

 	switch (nla_type(nested_attr)) {
 	case OVS_KEY_ATTR_PRIORITY:
 		skb->priority = nla_get_u32(nested_attr);
 		break;

 	case OVS_KEY_ATTR_SKB_MARK:
 		skb->mark = nla_get_u32(nested_attr);
 		break;

 	case OVS_KEY_ATTR_ETHERNET:
 		err = set_eth_addr(skb, nla_data(nested_attr));
 		break;

 	case OVS_KEY_ATTR_IPV4:
 		err = set_ipv4(skb, nla_data(nested_attr));
 		break;

 	case OVS_KEY_ATTR_IPV6:
 		err = set_ipv6(skb, nla_data(nested_attr));
 		break;

 	case OVS_KEY_ATTR_TCP:
 		err = set_tcp(skb, nla_data(nested_attr));
 		break;

 	case OVS_KEY_ATTR_UDP:
 		err = set_udp(skb, nla_data(nested_attr));
 		break;
 	}

 	return err;
 }

 /* Execute a list of actions against 'skb'. */
 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			const struct nlattr *attr, int len, bool keep_skb)
 {
 	/* Every output action needs a separate clone of 'skb', but the common
 	 * case is just a single output action, so that doing a clone and
 	 * then freeing the original skbuff is wasteful.  So the following code
 	 * is slightly obscure just to avoid that. */
 	int prev_port = -1;
 	const struct nlattr *a;
 	int rem;

 	for (a = attr, rem = len; rem > 0;
 	     a = nla_next(a, &rem)) {
 		int err = 0;

 		if (prev_port != -1) {
 			do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
 			prev_port = -1;
 		}

 		switch (nla_type(a)) {
 		case OVS_ACTION_ATTR_OUTPUT:
 			prev_port = nla_get_u32(a);
 			break;

 		case OVS_ACTION_ATTR_USERSPACE:
 			output_userspace(dp, skb, a);
 			break;

 		case OVS_ACTION_ATTR_PUSH_VLAN:
 			err = push_vlan(skb, nla_data(a));
 			if (unlikely(err)) /* skb already freed. */
 				return err;
 			break;

 		case OVS_ACTION_ATTR_POP_VLAN:
 			err = pop_vlan(skb);
 			break;

 		case OVS_ACTION_ATTR_SET:
 			err = execute_set_action(skb, nla_data(a));
 			break;

 		case OVS_ACTION_ATTR_SAMPLE:
 			err = sample(dp, skb, a);
 			break;
 		}

 		if (unlikely(err)) {
 			kfree_skb(skb);
 			return err;
 		}
 	}

 	if (prev_port != -1) {
 		if (keep_skb)
 			skb = skb_clone(skb, GFP_ATOMIC);

 		do_output(dp, skb, prev_port);
 	} else if (!keep_skb)
 		consume_skb(skb);

 	return 0;
 }

 /* Execute a list of actions against 'skb'. */
 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
 {
 	struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);

 	return do_execute_actions(dp, skb, acts->actions,
 					 acts->actions_len, false);
 }
	/*
	* Copyright (c) 2007-2012 Nicira, Inc.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of version 2 of the GNU General Public
	* License as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
	* 02110-1301, USA
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/skbuff.h>
	#include <linux/in.h>
	#include <linux/ip.h>
	#include <linux/openvswitch.h>
	#include <linux/tcp.h>
	#include <linux/udp.h>
	#include <linux/in6.h>
	#include <linux/if_arp.h>
	#include <linux/if_vlan.h>
	#include <net/ip.h>
	#include <net/ipv6.h>
	#include <net/checksum.h>
	#include <net/dsfield.h>

	#include "datapath.h"
	#include "vport.h"

	static int do_execute_actions(struct datapath dp, struct sk_buff skb,
	const struct nlattr *attr, int len, bool keep_skb);

	static int make_writable(struct sk_buff *skb, int write_len)
	{
	if (!skb_cloned(skb) \|\| skb_clone_writable(skb, write_len))
	return 0;

	return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
	}

	/* remove VLAN header from packet and update csum accordingly. */
	static int __pop_vlan_tci(struct sk_buff skb, __be16 current_tci)
	{
	struct vlan_hdr *vhdr;
	int err;

	err = make_writable(skb, VLAN_ETH_HLEN);
	if (unlikely(err))
	return err;

	if (skb->ip_summed == CHECKSUM_COMPLETE)
	skb->csum = csum_sub(skb->csum, csum_partial(skb->data
	+ (2 * ETH_ALEN), VLAN_HLEN, 0));

	vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
	*current_tci = vhdr->h_vlan_TCI;

	memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
	__skb_pull(skb, VLAN_HLEN);

	vlan_set_encap_proto(skb, vhdr);
	skb->mac_header += VLAN_HLEN;
	skb_reset_mac_len(skb);

	return 0;
	}

	static int pop_vlan(struct sk_buff *skb)
	{
	__be16 tci;
	int err;

	if (likely(vlan_tx_tag_present(skb))) {
	skb->vlan_tci = 0;
	} else {
	if (unlikely(skb->protocol != htons(ETH_P_8021Q) \|\|
	skb->len < VLAN_ETH_HLEN))
	return 0;

	err = __pop_vlan_tci(skb, &tci);
	if (err)
	return err;
	}
	/* move next vlan tag to hw accel tag */
	if (likely(skb->protocol != htons(ETH_P_8021Q) \|\|
	skb->len < VLAN_ETH_HLEN))
	return 0;

	err = __pop_vlan_tci(skb, &tci);
	if (unlikely(err))
	return err;

	__vlan_hwaccel_put_tag(skb, ntohs(tci));
	return 0;
	}

	static int push_vlan(struct sk_buff skb, const struct ovs_action_push_vlan vlan)
	{
	if (unlikely(vlan_tx_tag_present(skb))) {
	u16 current_tag;

	/* push down current VLAN tag */
	current_tag = vlan_tx_tag_get(skb);

	if (!__vlan_put_tag(skb, current_tag))
	return -ENOMEM;

	if (skb->ip_summed == CHECKSUM_COMPLETE)
	skb->csum = csum_add(skb->csum, csum_partial(skb->data
	+ (2 * ETH_ALEN), VLAN_HLEN, 0));

	}
	__vlan_hwaccel_put_tag(skb, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
	return 0;
	}

	static int set_eth_addr(struct sk_buff *skb,
	const struct ovs_key_ethernet *eth_key)
	{
	int err;
	err = make_writable(skb, ETH_HLEN);
	if (unlikely(err))
	return err;

	memcpy(eth_hdr(skb)->h_source, eth_key->eth_src, ETH_ALEN);
	memcpy(eth_hdr(skb)->h_dest, eth_key->eth_dst, ETH_ALEN);

	return 0;
	}

	static void set_ip_addr(struct sk_buff skb, struct iphdr nh,
	__be32 *addr, __be32 new_addr)
	{
	int transport_len = skb->len - skb_transport_offset(skb);

	if (nh->protocol == IPPROTO_TCP) {
	if (likely(transport_len >= sizeof(struct tcphdr)))
	inet_proto_csum_replace4(&tcp_hdr(skb)->check, skb,
	*addr, new_addr, 1);
	} else if (nh->protocol == IPPROTO_UDP) {
	if (likely(transport_len >= sizeof(struct udphdr))) {
	struct udphdr *uh = udp_hdr(skb);

	if (uh->check \|\| skb->ip_summed == CHECKSUM_PARTIAL) {
	inet_proto_csum_replace4(&uh->check, skb,
	*addr, new_addr, 1);
	if (!uh->check)
	uh->check = CSUM_MANGLED_0;
	}
	}
	}

	csum_replace4(&nh->check, *addr, new_addr);
	skb->rxhash = 0;
	*addr = new_addr;
	}

	static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
	__be32 addr[4], const __be32 new_addr[4])
	{
	int transport_len = skb->len - skb_transport_offset(skb);

	if (l4_proto == IPPROTO_TCP) {
	if (likely(transport_len >= sizeof(struct tcphdr)))
	inet_proto_csum_replace16(&tcp_hdr(skb)->check, skb,
	addr, new_addr, 1);
	} else if (l4_proto == IPPROTO_UDP) {
	if (likely(transport_len >= sizeof(struct udphdr))) {
	struct udphdr *uh = udp_hdr(skb);

	if (uh->check \|\| skb->ip_summed == CHECKSUM_PARTIAL) {
	inet_proto_csum_replace16(&uh->check, skb,
	addr, new_addr, 1);
	if (!uh->check)
	uh->check = CSUM_MANGLED_0;
	}
	}
	}
	}

	static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
	__be32 addr[4], const __be32 new_addr[4],
	bool recalculate_csum)
	{
	if (recalculate_csum)
	update_ipv6_checksum(skb, l4_proto, addr, new_addr);

	skb->rxhash = 0;
	memcpy(addr, new_addr, sizeof(__be32[4]));
	}

	static void set_ipv6_tc(struct ipv6hdr *nh, u8 tc)
	{
	nh->priority = tc >> 4;
	nh->flow_lbl[0] = (nh->flow_lbl[0] & 0x0F) \| ((tc & 0x0F) << 4);
	}

	static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl)
	{
	nh->flow_lbl[0] = (nh->flow_lbl[0] & 0xF0) \| (fl & 0x000F0000) >> 16;
	nh->flow_lbl[1] = (fl & 0x0000FF00) >> 8;
	nh->flow_lbl[2] = fl & 0x000000FF;
	}

	static void set_ip_ttl(struct sk_buff skb, struct iphdr nh, u8 new_ttl)
	{
	csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
	nh->ttl = new_ttl;
	}

	static int set_ipv4(struct sk_buff skb, const struct ovs_key_ipv4 ipv4_key)
	{
	struct iphdr *nh;
	int err;

	err = make_writable(skb, skb_network_offset(skb) +
	sizeof(struct iphdr));
	if (unlikely(err))
	return err;

	nh = ip_hdr(skb);

	if (ipv4_key->ipv4_src != nh->saddr)
	set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);

	if (ipv4_key->ipv4_dst != nh->daddr)
	set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);

	if (ipv4_key->ipv4_tos != nh->tos)
	ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);

	if (ipv4_key->ipv4_ttl != nh->ttl)
	set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);

	return 0;
	}

	static int set_ipv6(struct sk_buff skb, const struct ovs_key_ipv6 ipv6_key)
	{
	struct ipv6hdr *nh;
	int err;
	__be32 *saddr;
	__be32 *daddr;

	err = make_writable(skb, skb_network_offset(skb) +
	sizeof(struct ipv6hdr));
	if (unlikely(err))
	return err;

	nh = ipv6_hdr(skb);
	saddr = (__be32 *)&nh->saddr;
	daddr = (__be32 *)&nh->daddr;

	if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src)))
	set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
	ipv6_key->ipv6_src, true);

	if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
	unsigned int offset = 0;
	int flags = IP6_FH_F_SKIP_RH;
	bool recalc_csum = true;

	if (ipv6_ext_hdr(nh->nexthdr))
	recalc_csum = ipv6_find_hdr(skb, &offset,
	NEXTHDR_ROUTING, NULL,
	&flags) != NEXTHDR_ROUTING;

	set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
	ipv6_key->ipv6_dst, recalc_csum);
	}

	set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
	set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
	nh->hop_limit = ipv6_key->ipv6_hlimit;

	return 0;
	}

	/* Must follow make_writable() since that can move the skb data. */
	static void set_tp_port(struct sk_buff skb, __be16 port,
	__be16 new_port, __sum16 *check)
	{
	inet_proto_csum_replace2(check, skb, *port, new_port, 0);
	*port = new_port;
	skb->rxhash = 0;
	}

	static void set_udp_port(struct sk_buff skb, __be16 port, __be16 new_port)
	{
	struct udphdr *uh = udp_hdr(skb);

	if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
	set_tp_port(skb, port, new_port, &uh->check);

	if (!uh->check)
	uh->check = CSUM_MANGLED_0;
	} else {
	*port = new_port;
	skb->rxhash = 0;
	}
	}

	static int set_udp(struct sk_buff skb, const struct ovs_key_udp udp_port_key)
	{
	struct udphdr *uh;
	int err;

	err = make_writable(skb, skb_transport_offset(skb) +
	sizeof(struct udphdr));
	if (unlikely(err))
	return err;

	uh = udp_hdr(skb);
	if (udp_port_key->udp_src != uh->source)
	set_udp_port(skb, &uh->source, udp_port_key->udp_src);

	if (udp_port_key->udp_dst != uh->dest)
	set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);

	return 0;
	}

	static int set_tcp(struct sk_buff skb, const struct ovs_key_tcp tcp_port_key)
	{
	struct tcphdr *th;
	int err;

	err = make_writable(skb, skb_transport_offset(skb) +
	sizeof(struct tcphdr));
	if (unlikely(err))
	return err;

	th = tcp_hdr(skb);
	if (tcp_port_key->tcp_src != th->source)
	set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);

	if (tcp_port_key->tcp_dst != th->dest)
	set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);

	return 0;
	}

	static int do_output(struct datapath dp, struct sk_buff skb, int out_port)
	{
	struct vport *vport;

	if (unlikely(!skb))
	return -ENOMEM;

	vport = ovs_vport_rcu(dp, out_port);
	if (unlikely(!vport)) {
	kfree_skb(skb);
	return -ENODEV;
	}

	ovs_vport_send(vport, skb);
	return 0;
	}

	static int output_userspace(struct datapath dp, struct sk_buff skb,
	const struct nlattr *attr)
	{
	struct dp_upcall_info upcall;
	const struct nlattr *a;
	int rem;

	upcall.cmd = OVS_PACKET_CMD_ACTION;
	upcall.key = &OVS_CB(skb)->flow->key;
	upcall.userdata = NULL;
	upcall.portid = 0;

	for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
	a = nla_next(a, &rem)) {
	switch (nla_type(a)) {
	case OVS_USERSPACE_ATTR_USERDATA:
	upcall.userdata = a;
	break;

	case OVS_USERSPACE_ATTR_PID:
	upcall.portid = nla_get_u32(a);
	break;
	}
	}

	return ovs_dp_upcall(dp, skb, &upcall);
	}

	static int sample(struct datapath dp, struct sk_buff skb,
	const struct nlattr *attr)
	{
	const struct nlattr *acts_list = NULL;
	const struct nlattr *a;
	int rem;

	for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
	a = nla_next(a, &rem)) {
	switch (nla_type(a)) {
	case OVS_SAMPLE_ATTR_PROBABILITY:
	if (net_random() >= nla_get_u32(a))
	return 0;
	break;

	case OVS_SAMPLE_ATTR_ACTIONS:
	acts_list = a;
	break;
	}
	}

	return do_execute_actions(dp, skb, nla_data(acts_list),
	nla_len(acts_list), true);
	}

	static int execute_set_action(struct sk_buff *skb,
	const struct nlattr *nested_attr)
	{
	int err = 0;

	switch (nla_type(nested_attr)) {
	case OVS_KEY_ATTR_PRIORITY:
	skb->priority = nla_get_u32(nested_attr);
	break;

	case OVS_KEY_ATTR_SKB_MARK:
	skb->mark = nla_get_u32(nested_attr);
	break;

	case OVS_KEY_ATTR_ETHERNET:
	err = set_eth_addr(skb, nla_data(nested_attr));
	break;

	case OVS_KEY_ATTR_IPV4:
	err = set_ipv4(skb, nla_data(nested_attr));
	break;

	case OVS_KEY_ATTR_IPV6:
	err = set_ipv6(skb, nla_data(nested_attr));
	break;

	case OVS_KEY_ATTR_TCP:
	err = set_tcp(skb, nla_data(nested_attr));
	break;

	case OVS_KEY_ATTR_UDP:
	err = set_udp(skb, nla_data(nested_attr));
	break;
	}

	return err;
	}

	/* Execute a list of actions against 'skb'. */
	static int do_execute_actions(struct datapath dp, struct sk_buff skb,
	const struct nlattr *attr, int len, bool keep_skb)
	{
	/* Every output action needs a separate clone of 'skb', but the common
	* case is just a single output action, so that doing a clone and
	* then freeing the original skbuff is wasteful. So the following code
	* is slightly obscure just to avoid that. */
	int prev_port = -1;
	const struct nlattr *a;
	int rem;

	for (a = attr, rem = len; rem > 0;
	a = nla_next(a, &rem)) {
	int err = 0;

	if (prev_port != -1) {
	do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
	prev_port = -1;
	}

	switch (nla_type(a)) {
	case OVS_ACTION_ATTR_OUTPUT:
	prev_port = nla_get_u32(a);
	break;

	case OVS_ACTION_ATTR_USERSPACE:
	output_userspace(dp, skb, a);
	break;

	case OVS_ACTION_ATTR_PUSH_VLAN:
	err = push_vlan(skb, nla_data(a));
	if (unlikely(err)) /* skb already freed. */
	return err;
	break;

	case OVS_ACTION_ATTR_POP_VLAN:
	err = pop_vlan(skb);
	break;

	case OVS_ACTION_ATTR_SET:
	err = execute_set_action(skb, nla_data(a));
	break;

	case OVS_ACTION_ATTR_SAMPLE:
	err = sample(dp, skb, a);
	break;
	}

	if (unlikely(err)) {
	kfree_skb(skb);
	return err;
	}
	}

	if (prev_port != -1) {
	if (keep_skb)
	skb = skb_clone(skb, GFP_ATOMIC);

	do_output(dp, skb, prev_port);
	} else if (!keep_skb)
	consume_skb(skb);

	return 0;
	}

	/* Execute a list of actions against 'skb'. */
	int ovs_execute_actions(struct datapath dp, struct sk_buff skb)
	{
	struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);

	return do_execute_actions(dp, skb, acts->actions,
	acts->actions_len, false);
	}