[ovs.git] / datapath / flow.c

/*
 * Distributed under the terms of the GNU GPL version 2.
 * Copyright (c) 2007, 2008, 2009, 2010 Nicira Networks.
 *
 * Significant portions of this file may be copied from parts of the Linux
 * kernel, by Linus Torvalds and others.
 */

#include "flow.h"
#include "datapath.h"
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <net/llc_pdu.h>
#include <linux/kernel.h>
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/llc.h>
#include <linux/module.h>
#include <linux/in.h>
#include <linux/rcupdate.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <net/inet_ecn.h>
#include <net/ip.h>

#include "compat.h"

struct kmem_cache *flow_cache;
static unsigned int hash_seed;

struct arp_eth_header
{
	__be16      ar_hrd;	/* format of hardware address   */
	__be16      ar_pro;	/* format of protocol address   */
	unsigned char   ar_hln;	/* length of hardware address   */
	unsigned char   ar_pln;	/* length of protocol address   */
	__be16      ar_op;	/* ARP opcode (command)     */

	/* Ethernet+IPv4 specific members. */
	unsigned char       ar_sha[ETH_ALEN];	/* sender hardware address  */
	unsigned char       ar_sip[4];		/* sender IP address        */
	unsigned char       ar_tha[ETH_ALEN];	/* target hardware address  */
	unsigned char       ar_tip[4];		/* target IP address        */
} __attribute__((packed));

static inline int arphdr_ok(struct sk_buff *skb)
{
	int nh_ofs = skb_network_offset(skb);
	return pskb_may_pull(skb, nh_ofs + sizeof(struct arp_eth_header));
}

static inline int iphdr_ok(struct sk_buff *skb)
{
	int nh_ofs = skb_network_offset(skb);
	if (skb->len >= nh_ofs + sizeof(struct iphdr)) {
		int ip_len = ip_hdrlen(skb);
		return (ip_len >= sizeof(struct iphdr)
			&& pskb_may_pull(skb, nh_ofs + ip_len));
	}
	return 0;
}

static inline int tcphdr_ok(struct sk_buff *skb)
{
	int th_ofs = skb_transport_offset(skb);
	if (pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))) {
		int tcp_len = tcp_hdrlen(skb);
		return (tcp_len >= sizeof(struct tcphdr)
			&& skb->len >= th_ofs + tcp_len);
	}
	return 0;
}

static inline int udphdr_ok(struct sk_buff *skb)
{
	int th_ofs = skb_transport_offset(skb);
	return pskb_may_pull(skb, th_ofs + sizeof(struct udphdr));
}

static inline int icmphdr_ok(struct sk_buff *skb)
{
	int th_ofs = skb_transport_offset(skb);
	return pskb_may_pull(skb, th_ofs + sizeof(struct icmphdr));
}

#define TCP_FLAGS_OFFSET 13
#define TCP_FLAG_MASK 0x3f

void flow_used(struct sw_flow *flow, struct sk_buff *skb)
{
	u8 tcp_flags = 0;

	if (flow->key.dl_type == htons(ETH_P_IP) &&
	    flow->key.nw_proto == IPPROTO_TCP) {
		u8 *tcp = (u8 *)tcp_hdr(skb);
		tcp_flags = *(tcp + TCP_FLAGS_OFFSET) & TCP_FLAG_MASK;
	}

	spin_lock_bh(&flow->lock);
	flow->used = jiffies;
	flow->packet_count++;
	flow->byte_count += skb->len;
	flow->tcp_flags |= tcp_flags;
	spin_unlock_bh(&flow->lock);
}

struct sw_flow_actions *flow_actions_alloc(size_t n_actions)
{
	struct sw_flow_actions *sfa;

	if (n_actions > (PAGE_SIZE - sizeof *sfa) / sizeof(union odp_action))
		return ERR_PTR(-EINVAL);

	sfa = kmalloc(sizeof *sfa + n_actions * sizeof(union odp_action),
		      GFP_KERNEL);
	if (!sfa)
		return ERR_PTR(-ENOMEM);

	sfa->n_actions = n_actions;
	return sfa;
}


/* Frees 'flow' immediately. */
static void flow_free(struct sw_flow *flow)
{
	if (unlikely(!flow))
		return;
	kfree(flow->sf_acts);
	kmem_cache_free(flow_cache, flow);
}

void flow_free_tbl(struct tbl_node *node)
{
	struct sw_flow *flow = flow_cast(node);
	flow_free(flow);
}

/* RCU callback used by flow_deferred_free. */
static void rcu_free_flow_callback(struct rcu_head *rcu)
{
	struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
	flow_free(flow);
}

/* Schedules 'flow' to be freed after the next RCU grace period.
 * The caller must hold rcu_read_lock for this to be sensible. */
void flow_deferred_free(struct sw_flow *flow)
{
	call_rcu(&flow->rcu, rcu_free_flow_callback);
}

/* RCU callback used by flow_deferred_free_acts. */
static void rcu_free_acts_callback(struct rcu_head *rcu)
{
	struct sw_flow_actions *sf_acts = container_of(rcu, 
			struct sw_flow_actions, rcu);
	kfree(sf_acts);
}

/* Schedules 'sf_acts' to be freed after the next RCU grace period.
 * The caller must hold rcu_read_lock for this to be sensible. */
void flow_deferred_free_acts(struct sw_flow_actions *sf_acts)
{
	call_rcu(&sf_acts->rcu, rcu_free_acts_callback);
}

static void parse_vlan(struct sk_buff *skb, struct odp_flow_key *key)
{
	struct qtag_prefix {
		__be16 eth_type; /* ETH_P_8021Q */
		__be16 tci;
	};
	struct qtag_prefix *qp;

	if (skb->len < sizeof(struct qtag_prefix) + sizeof(__be16))
		return;

	qp = (struct qtag_prefix *) skb->data;
	key->dl_vlan = qp->tci & htons(VLAN_VID_MASK);
	key->dl_vlan_pcp = (ntohs(qp->tci) & VLAN_PCP_MASK) >> VLAN_PCP_SHIFT;
	__skb_pull(skb, sizeof(struct qtag_prefix));
}

static __be16 parse_ethertype(struct sk_buff *skb)
{
	struct llc_snap_hdr {
		u8  dsap;  /* Always 0xAA */
		u8  ssap;  /* Always 0xAA */
		u8  ctrl;
		u8  oui[3];
		u16 ethertype;
	};
	struct llc_snap_hdr *llc;
	__be16 proto;

	proto = *(__be16 *) skb->data;
	__skb_pull(skb, sizeof(__be16));

	if (ntohs(proto) >= ODP_DL_TYPE_ETH2_CUTOFF)
		return proto;

	if (unlikely(skb->len < sizeof(struct llc_snap_hdr)))
		return htons(ODP_DL_TYPE_NOT_ETH_TYPE);

	llc = (struct llc_snap_hdr *) skb->data;
	if (llc->dsap != LLC_SAP_SNAP ||
	    llc->ssap != LLC_SAP_SNAP ||
	    (llc->oui[0] | llc->oui[1] | llc->oui[2]) != 0)
		return htons(ODP_DL_TYPE_NOT_ETH_TYPE);

	__skb_pull(skb, sizeof(struct llc_snap_hdr));
	return llc->ethertype;
}

/* Parses the Ethernet frame in 'skb', which was received on 'in_port',
 * and initializes 'key' to match.  Returns 1 if 'skb' contains an IP
 * fragment, 0 otherwise. */
int flow_extract(struct sk_buff *skb, u16 in_port, struct odp_flow_key *key)
{
	struct ethhdr *eth;
	int retval = 0;

	memset(key, 0, sizeof *key);
	key->tun_id = OVS_CB(skb)->tun_id;
	key->in_port = in_port;
	key->dl_vlan = htons(ODP_VLAN_NONE);

	if (skb->len < sizeof *eth)
		return 0;
	if (!pskb_may_pull(skb, min(skb->len, 64u)))
		return 0;

	skb_reset_mac_header(skb);

	/* Link layer. */
	eth = eth_hdr(skb);
	memcpy(key->dl_src, eth->h_source, ETH_ALEN);
	memcpy(key->dl_dst, eth->h_dest, ETH_ALEN);

	/* dl_type, dl_vlan, dl_vlan_pcp. */
	__skb_pull(skb, 2 * ETH_ALEN);
	if (eth->h_proto == htons(ETH_P_8021Q))
		parse_vlan(skb, key);
	key->dl_type = parse_ethertype(skb);
	skb_reset_network_header(skb);
	__skb_push(skb, skb->data - (unsigned char *)eth);

	/* Network layer. */
	if (key->dl_type == htons(ETH_P_IP) && iphdr_ok(skb)) {
		struct iphdr *nh = ip_hdr(skb);
		int th_ofs = skb_network_offset(skb) + nh->ihl * 4;
		key->nw_src = nh->saddr;
		key->nw_dst = nh->daddr;
		key->nw_tos = nh->tos & ~INET_ECN_MASK;
		key->nw_proto = nh->protocol;
		skb_set_transport_header(skb, th_ofs);

		/* Transport layer. */
		if (!(nh->frag_off & htons(IP_MF | IP_OFFSET))) {
			if (key->nw_proto == IPPROTO_TCP) {
				if (tcphdr_ok(skb)) {
					struct tcphdr *tcp = tcp_hdr(skb);
					key->tp_src = tcp->source;
					key->tp_dst = tcp->dest;
				} else {
					/* Avoid tricking other code into
					 * thinking that this packet has an L4
					 * header. */
					key->nw_proto = 0;
				}
			} else if (key->nw_proto == IPPROTO_UDP) {
				if (udphdr_ok(skb)) {
					struct udphdr *udp = udp_hdr(skb);
					key->tp_src = udp->source;
					key->tp_dst = udp->dest;
				} else {
					/* Avoid tricking other code into
					 * thinking that this packet has an L4
					 * header. */
					key->nw_proto = 0;
				}
			} else if (key->nw_proto == IPPROTO_ICMP) {
				if (icmphdr_ok(skb)) {
					struct icmphdr *icmp = icmp_hdr(skb);
					/* The ICMP type and code fields use the 16-bit
					 * transport port fields, so we need to store them
					 * in 16-bit network byte order. */
					key->tp_src = htons(icmp->type);
					key->tp_dst = htons(icmp->code);
				} else {
					/* Avoid tricking other code into
					 * thinking that this packet has an L4
					 * header. */
					key->nw_proto = 0;
				}
			}
		} else {
			retval = 1;
		}
	} else if (key->dl_type == htons(ETH_P_ARP) && arphdr_ok(skb)) {
		struct arp_eth_header *arp;

		arp = (struct arp_eth_header *)skb_network_header(skb);

		if (arp->ar_hrd == htons(ARPHRD_ETHER)
				&& arp->ar_pro == htons(ETH_P_IP)
				&& arp->ar_hln == ETH_ALEN
				&& arp->ar_pln == 4) {

			/* We only match on the lower 8 bits of the opcode. */
			if (ntohs(arp->ar_op) <= 0xff) {
				key->nw_proto = ntohs(arp->ar_op);
			}

			if (key->nw_proto == ARPOP_REQUEST 
					|| key->nw_proto == ARPOP_REPLY) {
				memcpy(&key->nw_src, arp->ar_sip, sizeof(key->nw_src));
				memcpy(&key->nw_dst, arp->ar_tip, sizeof(key->nw_dst));
			}
		}
	} else {
		skb_reset_transport_header(skb);
	}
	return retval;
}

u32 flow_hash(const struct odp_flow_key *key)
{
	return jhash2((u32*)key, sizeof *key / sizeof(u32), hash_seed);
}

int flow_cmp(const struct tbl_node *node, void *key2_)
{
	const struct odp_flow_key *key1 = &flow_cast(node)->key;
	const struct odp_flow_key *key2 = key2_;

	return !memcmp(key1, key2, sizeof(struct odp_flow_key));
}

/* Initializes the flow module.
 * Returns zero if successful or a negative error code. */
int flow_init(void)
{
	flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
					0, NULL);
	if (flow_cache == NULL)
		return -ENOMEM;

	get_random_bytes(&hash_seed, sizeof hash_seed);

	return 0;
}

/* Uninitializes the flow module. */
void flow_exit(void)
{
	kmem_cache_destroy(flow_cache);
}
Commit	Line	Data
064af421 BP	1	/*
064af421 BP	2	* Distributed under the terms of the GNU GPL version 2.
834377ea	3	* Copyright (c) 2007, 2008, 2009, 2010 Nicira Networks.
a14bc59f BP	4	*
	5	* Significant portions of this file may be copied from parts of the Linux
	6	* kernel, by Linus Torvalds and others.
064af421 BP	7	*/
	8
	9	#include "flow.h"
f5e86186	10	#include "datapath.h"
064af421 BP	11	#include <linux/netdevice.h>
	12	#include <linux/etherdevice.h>
	13	#include <linux/if_ether.h>
	14	#include <linux/if_vlan.h>
	15	#include <net/llc_pdu.h>
	16	#include <linux/kernel.h>
8d5ebd83	17	#include <linux/jhash.h>
064af421 BP	18	#include <linux/jiffies.h>
	19	#include <linux/llc.h>
	20	#include <linux/module.h>
	21	#include <linux/in.h>
	22	#include <linux/rcupdate.h>
a26ef517	23	#include <linux/if_arp.h>
064af421 BP	24	#include <linux/if_ether.h>
	25	#include <linux/ip.h>
	26	#include <linux/tcp.h>
	27	#include <linux/udp.h>
	28	#include <linux/icmp.h>
3c5f6de3	29	#include <net/inet_ecn.h>
064af421 BP	30	#include <net/ip.h>
	31
	32	#include "compat.h"
	33
	34	struct kmem_cache *flow_cache;
8d5ebd83	35	static unsigned int hash_seed;
064af421	36
a26ef517 JP	37	struct arp_eth_header
	38	{
	39	__be16 ar_hrd; /* format of hardware address */
	40	__be16 ar_pro; /* format of protocol address */
	41	unsigned char ar_hln; /* length of hardware address */
	42	unsigned char ar_pln; /* length of protocol address */
	43	__be16 ar_op; /* ARP opcode (command) */
	44
	45	/* Ethernet+IPv4 specific members. */
	46	unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */
	47	unsigned char ar_sip[4]; /* sender IP address */
	48	unsigned char ar_tha[ETH_ALEN]; /* target hardware address */
	49	unsigned char ar_tip[4]; /* target IP address */
	50	} __attribute__((packed));
	51
	52	static inline int arphdr_ok(struct sk_buff *skb)
	53	{
	54	int nh_ofs = skb_network_offset(skb);
	55	return pskb_may_pull(skb, nh_ofs + sizeof(struct arp_eth_header));
	56	}
	57
064af421 BP	58	static inline int iphdr_ok(struct sk_buff *skb)
	59	{
	60	int nh_ofs = skb_network_offset(skb);
	61	if (skb->len >= nh_ofs + sizeof(struct iphdr)) {
	62	int ip_len = ip_hdrlen(skb);
	63	return (ip_len >= sizeof(struct iphdr)
	64	&& pskb_may_pull(skb, nh_ofs + ip_len));
	65	}
	66	return 0;
	67	}
	68
	69	static inline int tcphdr_ok(struct sk_buff *skb)
	70	{
	71	int th_ofs = skb_transport_offset(skb);
	72	if (pskb_may_pull(skb, th_ofs + sizeof(struct tcphdr))) {
	73	int tcp_len = tcp_hdrlen(skb);
	74	return (tcp_len >= sizeof(struct tcphdr)
	75	&& skb->len >= th_ofs + tcp_len);
	76	}
	77	return 0;
	78	}
	79
	80	static inline int udphdr_ok(struct sk_buff *skb)
	81	{
	82	int th_ofs = skb_transport_offset(skb);
	83	return pskb_may_pull(skb, th_ofs + sizeof(struct udphdr));
	84	}
	85
	86	static inline int icmphdr_ok(struct sk_buff *skb)
	87	{
	88	int th_ofs = skb_transport_offset(skb);
	89	return pskb_may_pull(skb, th_ofs + sizeof(struct icmphdr));
	90	}
	91
	92	#define TCP_FLAGS_OFFSET 13
	93	#define TCP_FLAG_MASK 0x3f
	94
064af421 BP	95	void flow_used(struct sw_flow flow, struct sk_buff skb)
064af421 BP	96	{
064af421 BP	97	u8 tcp_flags = 0;
064af421 BP	98
abfec865 BP	99	if (flow->key.dl_type == htons(ETH_P_IP) &&
	100	flow->key.nw_proto == IPPROTO_TCP) {
	101	u8 tcp = (u8 )tcp_hdr(skb);
	102	tcp_flags = *(tcp + TCP_FLAGS_OFFSET) & TCP_FLAG_MASK;
064af421 BP	103	}
064af421 BP	104
f2459fe7	105	spin_lock_bh(&flow->lock);
6bfafa55	106	flow->used = jiffies;
064af421 BP	107	flow->packet_count++;
	108	flow->byte_count += skb->len;
	109	flow->tcp_flags \|= tcp_flags;
f2459fe7	110	spin_unlock_bh(&flow->lock);
064af421 BP	111	}
	112
	113	struct sw_flow_actions *flow_actions_alloc(size_t n_actions)
	114	{
	115	struct sw_flow_actions *sfa;
	116
	117	if (n_actions > (PAGE_SIZE - sizeof *sfa) / sizeof(union odp_action))
	118	return ERR_PTR(-EINVAL);
	119
	120	sfa = kmalloc(sizeof sfa + n_actions sizeof(union odp_action),
	121	GFP_KERNEL);
	122	if (!sfa)
	123	return ERR_PTR(-ENOMEM);
	124
	125	sfa->n_actions = n_actions;
	126	return sfa;
	127	}
	128
	129
	130	/* Frees 'flow' immediately. */
8d5ebd83	131	static void flow_free(struct sw_flow *flow)
064af421 BP	132	{
	133	if (unlikely(!flow))
	134	return;
	135	kfree(flow->sf_acts);
	136	kmem_cache_free(flow_cache, flow);
	137	}
	138
8d5ebd83 JG	139	void flow_free_tbl(struct tbl_node *node)
	140	{
	141	struct sw_flow *flow = flow_cast(node);
	142	flow_free(flow);
	143	}
	144
064af421 BP	145	/* RCU callback used by flow_deferred_free. */
	146	static void rcu_free_flow_callback(struct rcu_head *rcu)
	147	{
	148	struct sw_flow *flow = container_of(rcu, struct sw_flow, rcu);
	149	flow_free(flow);
	150	}
	151
	152	/* Schedules 'flow' to be freed after the next RCU grace period.
	153	* The caller must hold rcu_read_lock for this to be sensible. */
	154	void flow_deferred_free(struct sw_flow *flow)
	155	{
	156	call_rcu(&flow->rcu, rcu_free_flow_callback);
	157	}
	158
	159	/* RCU callback used by flow_deferred_free_acts. */
	160	static void rcu_free_acts_callback(struct rcu_head *rcu)
	161	{
	162	struct sw_flow_actions *sf_acts = container_of(rcu,
	163	struct sw_flow_actions, rcu);
	164	kfree(sf_acts);
	165	}
	166
	167	/* Schedules 'sf_acts' to be freed after the next RCU grace period.
	168	* The caller must hold rcu_read_lock for this to be sensible. */
	169	void flow_deferred_free_acts(struct sw_flow_actions *sf_acts)
	170	{
	171	call_rcu(&sf_acts->rcu, rcu_free_acts_callback);
	172	}
	173
50f06e16	174	static void parse_vlan(struct sk_buff skb, struct odp_flow_key key)
064af421	175	{
50f06e16 BP	176	struct qtag_prefix {
	177	__be16 eth_type; /* ETH_P_8021Q */
	178	__be16 tci;
	179	};
	180	struct qtag_prefix *qp;
	181
	182	if (skb->len < sizeof(struct qtag_prefix) + sizeof(__be16))
	183	return;
	184
	185	qp = (struct qtag_prefix *) skb->data;
	186	key->dl_vlan = qp->tci & htons(VLAN_VID_MASK);
	187	key->dl_vlan_pcp = (ntohs(qp->tci) & VLAN_PCP_MASK) >> VLAN_PCP_SHIFT;
	188	__skb_pull(skb, sizeof(struct qtag_prefix));
	189	}
	190
	191	static __be16 parse_ethertype(struct sk_buff *skb)
064af421	192	{
50f06e16 BP	193	struct llc_snap_hdr {
	194	u8 dsap; /* Always 0xAA */
	195	u8 ssap; /* Always 0xAA */
	196	u8 ctrl;
	197	u8 oui[3];
	198	u16 ethertype;
	199	};
	200	struct llc_snap_hdr *llc;
	201	__be16 proto;
	202
	203	proto = (__be16 ) skb->data;
	204	__skb_pull(skb, sizeof(__be16));
	205
	206	if (ntohs(proto) >= ODP_DL_TYPE_ETH2_CUTOFF)
	207	return proto;
	208
	209	if (unlikely(skb->len < sizeof(struct llc_snap_hdr)))
	210	return htons(ODP_DL_TYPE_NOT_ETH_TYPE);
	211
	212	llc = (struct llc_snap_hdr *) skb->data;
	213	if (llc->dsap != LLC_SAP_SNAP \|\|
	214	llc->ssap != LLC_SAP_SNAP \|\|
	215	(llc->oui[0] \| llc->oui[1] \| llc->oui[2]) != 0)
	216	return htons(ODP_DL_TYPE_NOT_ETH_TYPE);
	217
	218	__skb_pull(skb, sizeof(struct llc_snap_hdr));
	219	return llc->ethertype;
064af421 BP	220	}
	221
	222	/* Parses the Ethernet frame in 'skb', which was received on 'in_port',
	223	* and initializes 'key' to match. Returns 1 if 'skb' contains an IP
	224	* fragment, 0 otherwise. */
	225	int flow_extract(struct sk_buff skb, u16 in_port, struct odp_flow_key key)
	226	{
	227	struct ethhdr *eth;
064af421	228	int retval = 0;
064af421 BP	229
064af421 BP	230	memset(key, 0, sizeof *key);
659586ef	231	key->tun_id = OVS_CB(skb)->tun_id;
064af421	232	key->in_port = in_port;
659586ef	233	key->dl_vlan = htons(ODP_VLAN_NONE);
064af421 BP	234
	235	if (skb->len < sizeof *eth)
	236	return 0;
d9fce1ca	237	if (!pskb_may_pull(skb, min(skb->len, 64u)))
064af421	238	return 0;
064af421 BP	239
064af421 BP	240	skb_reset_mac_header(skb);
064af421	241
50f06e16 BP	242	/* Link layer. */
50f06e16 BP	243	eth = eth_hdr(skb);
064af421 BP	244	memcpy(key->dl_src, eth->h_source, ETH_ALEN);
064af421 BP	245	memcpy(key->dl_dst, eth->h_dest, ETH_ALEN);
50f06e16 BP	246
	247	/* dl_type, dl_vlan, dl_vlan_pcp. */
	248	__skb_pull(skb, 2 * ETH_ALEN);
	249	if (eth->h_proto == htons(ETH_P_8021Q))
	250	parse_vlan(skb, key);
	251	key->dl_type = parse_ethertype(skb);
	252	skb_reset_network_header(skb);
	253	__skb_push(skb, skb->data - (unsigned char *)eth);
064af421 BP	254
	255	/* Network layer. */
	256	if (key->dl_type == htons(ETH_P_IP) && iphdr_ok(skb)) {
	257	struct iphdr *nh = ip_hdr(skb);
50f06e16	258	int th_ofs = skb_network_offset(skb) + nh->ihl * 4;
064af421 BP	259	key->nw_src = nh->saddr;
064af421 BP	260	key->nw_dst = nh->daddr;
f5e86186	261	key->nw_tos = nh->tos & ~INET_ECN_MASK;
064af421 BP	262	key->nw_proto = nh->protocol;
	263	skb_set_transport_header(skb, th_ofs);
	264
	265	/* Transport layer. */
	266	if (!(nh->frag_off & htons(IP_MF \| IP_OFFSET))) {
	267	if (key->nw_proto == IPPROTO_TCP) {
	268	if (tcphdr_ok(skb)) {
	269	struct tcphdr *tcp = tcp_hdr(skb);
	270	key->tp_src = tcp->source;
	271	key->tp_dst = tcp->dest;
	272	} else {
	273	/* Avoid tricking other code into
	274	* thinking that this packet has an L4
	275	* header. */
	276	key->nw_proto = 0;
	277	}
	278	} else if (key->nw_proto == IPPROTO_UDP) {
	279	if (udphdr_ok(skb)) {
	280	struct udphdr *udp = udp_hdr(skb);
	281	key->tp_src = udp->source;
	282	key->tp_dst = udp->dest;
	283	} else {
	284	/* Avoid tricking other code into
	285	* thinking that this packet has an L4
	286	* header. */
	287	key->nw_proto = 0;
	288	}
	289	} else if (key->nw_proto == IPPROTO_ICMP) {
	290	if (icmphdr_ok(skb)) {
	291	struct icmphdr *icmp = icmp_hdr(skb);
	292	/* The ICMP type and code fields use the 16-bit
	293	* transport port fields, so we need to store them
	294	* in 16-bit network byte order. */
	295	key->tp_src = htons(icmp->type);
	296	key->tp_dst = htons(icmp->code);
	297	} else {
	298	/* Avoid tricking other code into
	299	* thinking that this packet has an L4
	300	* header. */
	301	key->nw_proto = 0;
	302	}
	303	}
	304	} else {
	305	retval = 1;
	306	}
a26ef517 JP	307	} else if (key->dl_type == htons(ETH_P_ARP) && arphdr_ok(skb)) {
	308	struct arp_eth_header *arp;
	309
	310	arp = (struct arp_eth_header *)skb_network_header(skb);
	311
f5e86186	312	if (arp->ar_hrd == htons(ARPHRD_ETHER)
de3f65ea JP	313	&& arp->ar_pro == htons(ETH_P_IP)
	314	&& arp->ar_hln == ETH_ALEN
	315	&& arp->ar_pln == 4) {
	316
	317	/* We only match on the lower 8 bits of the opcode. */
	318	if (ntohs(arp->ar_op) <= 0xff) {
	319	key->nw_proto = ntohs(arp->ar_op);
	320	}
	321
	322	if (key->nw_proto == ARPOP_REQUEST
	323	\|\| key->nw_proto == ARPOP_REPLY) {
	324	memcpy(&key->nw_src, arp->ar_sip, sizeof(key->nw_src));
	325	memcpy(&key->nw_dst, arp->ar_tip, sizeof(key->nw_dst));
	326	}
	327	}
064af421 BP	328	} else {
	329	skb_reset_transport_header(skb);
	330	}
	331	return retval;
	332	}
	333
8d5ebd83 JG	334	u32 flow_hash(const struct odp_flow_key *key)
	335	{
	336	return jhash2((u32)key, sizeof key / sizeof(u32), hash_seed);
	337	}
	338
	339	int flow_cmp(const struct tbl_node node, void key2_)
	340	{
	341	const struct odp_flow_key *key1 = &flow_cast(node)->key;
	342	const struct odp_flow_key *key2 = key2_;
	343
	344	return !memcmp(key1, key2, sizeof(struct odp_flow_key));
	345	}
	346
064af421 BP	347	/* Initializes the flow module.
	348	* Returns zero if successful or a negative error code. */
	349	int flow_init(void)
	350	{
	351	flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
	352	0, NULL);
	353	if (flow_cache == NULL)
	354	return -ENOMEM;
	355
8d5ebd83 JG	356	get_random_bytes(&hash_seed, sizeof hash_seed);
8d5ebd83 JG	357
064af421 BP	358	return 0;
	359	}
	360
	361	/* Uninitializes the flow module. */
	362	void flow_exit(void)
	363	{
	364	kmem_cache_destroy(flow_cache);
	365	}