[openvswitch] / datapath / datapath.c

/*
 * Distributed under the terms of the GNU GPL version 2.
 * Copyright (c) 2007, 2008 The Board of Trustees of The Leland 
 * Stanford Junior University
 */

/* Functions for managing the dp interface/device. */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/if_bridge.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <net/genetlink.h>
#include <linux/ip.h>
#include <linux/delay.h>
#include <linux/etherdevice.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/rtnetlink.h>
#include <linux/rcupdate.h>
#include <linux/version.h>
#include <linux/ethtool.h>
#include <linux/random.h>
#include <asm/system.h>
#include <linux/netfilter_bridge.h>
#include <linux/inetdevice.h>
#include <linux/list.h>

#include "openflow-netlink.h"
#include "datapath.h"
#include "table.h"
#include "chain.h"
#include "forward.h"
#include "flow.h"
#include "datapath_t.h"

#include "compat.h"


/* Number of milliseconds between runs of the maintenance thread. */
#define MAINT_SLEEP_MSECS 1000

#define BRIDGE_PORT_NO_FLOOD    0x00000001 

#define UINT32_MAX                        4294967295U
#define UINT16_MAX                        65535
#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))

struct net_bridge_port {
        u16     port_no;
        u32 flags;
        struct datapath *dp;
        struct net_device *dev;
        struct list_head node; /* Element in datapath.ports. */
};

static struct genl_family dp_genl_family;
static struct genl_multicast_group mc_group;

int dp_dev_setup(struct net_device *dev);  

/* It's hard to imagine wanting more than one datapath, but... */
#define DP_MAX 32

/* datapaths.  Protected on the read side by rcu_read_lock, on the write side
 * by dp_mutex.
 *
 * It is safe to access the datapath and net_bridge_port structures with just
 * the dp_mutex, but to access the chain you need to take the rcu_read_lock
 * also (because dp_mutex doesn't prevent flows from being destroyed).
 */
static struct datapath *dps[DP_MAX];
static DEFINE_MUTEX(dp_mutex);

static int dp_maint_func(void *data);
static int send_port_status(struct net_bridge_port *p, uint8_t status);
static int dp_genl_openflow_done(struct netlink_callback *);

/* nla_shrink - reduce amount of space reserved by nla_reserve
 * @skb: socket buffer from which to recover room
 * @nla: netlink attribute to adjust
 * @len: new length of attribute payload
 *
 * Reduces amount of space reserved by a call to nla_reserve.
 *
 * No other attributes may be added between calling nla_reserve and this
 * function, since it will create a hole in the message.
 */
void nla_shrink(struct sk_buff *skb, struct nlattr *nla, int len)
{
        int delta = nla_total_size(len) - nla_total_size(nla_len(nla));
        BUG_ON(delta > 0);
        skb->tail += delta;
        skb->len  += delta;
        nla->nla_len = nla_attr_size(len);
}

/* Puts a set of openflow headers for a message of the given 'type' into 'skb'.
 * If 'sender' is nonnull, then it is used as the message's destination.  'dp'
 * must specify the datapath to use.
 *
 * '*max_openflow_len' receives the maximum number of bytes that are available
 * for the embedded OpenFlow message.  The caller must call
 * resize_openflow_skb() to set the actual size of the message to this number
 * of bytes or less.
 *
 * Returns the openflow header if successful, otherwise (if 'skb' is too small)
 * an error code. */
static void *
put_openflow_headers(struct datapath *dp, struct sk_buff *skb, uint8_t type,
                     const struct sender *sender, int *max_openflow_len)
{
        struct ofp_header *oh;
        struct nlattr *attr;
        int openflow_len;

        /* Assemble the Generic Netlink wrapper. */
        if (!genlmsg_put(skb,
                         sender ? sender->pid : 0,
                         sender ? sender->seq : 0,
                         &dp_genl_family, 0, DP_GENL_C_OPENFLOW))
                return ERR_PTR(-ENOBUFS);
        if (nla_put_u32(skb, DP_GENL_A_DP_IDX, dp->dp_idx) < 0)
                return ERR_PTR(-ENOBUFS);
        openflow_len = (skb_tailroom(skb) - NLA_HDRLEN) & ~(NLA_ALIGNTO - 1);
        if (openflow_len < sizeof *oh)
                return ERR_PTR(-ENOBUFS);
        *max_openflow_len = openflow_len;
        attr = nla_reserve(skb, DP_GENL_A_OPENFLOW, openflow_len);
        BUG_ON(!attr);

        /* Fill in the header.  The caller is responsible for the length. */
        oh = nla_data(attr);
        oh->version = OFP_VERSION;
        oh->type = type;
        oh->xid = sender ? sender->xid : 0;

        return oh;
}

/* Resizes OpenFlow header 'oh', which must be at the tail end of 'skb', to new
 * length 'new_length' (in bytes), adjusting pointers and size values as
 * necessary. */
static void
resize_openflow_skb(struct sk_buff *skb,
                    struct ofp_header *oh, size_t new_length)
{
        struct nlattr *attr = ((void *) oh) - NLA_HDRLEN;
        nla_shrink(skb, attr, new_length);
        oh->length = htons(new_length);
        nlmsg_end(skb, (struct nlmsghdr *) skb->data);
}

/* Allocates a new skb to contain an OpenFlow message 'openflow_len' bytes in
 * length.  Returns a null pointer if memory is unavailable, otherwise returns
 * the OpenFlow header and stores a pointer to the skb in '*pskb'. 
 *
 * 'type' is the OpenFlow message type.  If 'sender' is nonnull, then it is
 * used as the message's destination.  'dp' must specify the datapath to
 * use.  */
static void *
alloc_openflow_skb(struct datapath *dp, size_t openflow_len, uint8_t type,
                   const struct sender *sender, struct sk_buff **pskb) 
{
        struct ofp_header *oh;
        size_t genl_len;
        struct sk_buff *skb;
        int max_openflow_len;

        if ((openflow_len + sizeof(struct ofp_header)) > UINT16_MAX) {
                if (net_ratelimit())
                        printk("alloc_openflow_skb: openflow message too large: %zu\n", 
                                        openflow_len);
                return NULL;
        }

        genl_len = nlmsg_total_size(GENL_HDRLEN + dp_genl_family.hdrsize);
        genl_len += nla_total_size(sizeof(uint32_t)); /* DP_GENL_A_DP_IDX */
        genl_len += nla_total_size(openflow_len);    /* DP_GENL_A_OPENFLOW */
        skb = *pskb = genlmsg_new(genl_len, GFP_ATOMIC);
        if (!skb) {
                if (net_ratelimit())
                        printk("alloc_openflow_skb: genlmsg_new failed\n");
                return NULL;
        }

        oh = put_openflow_headers(dp, skb, type, sender, &max_openflow_len);
        BUG_ON(!oh || IS_ERR(oh));
        resize_openflow_skb(skb, oh, openflow_len);

        return oh;
}

/* Sends 'skb' to 'sender' if it is nonnull, otherwise multicasts 'skb' to all
 * listeners. */
static int
send_openflow_skb(struct sk_buff *skb, const struct sender *sender) 
{
        int err = (sender
                   ? genlmsg_unicast(skb, sender->pid)
                   : genlmsg_multicast(skb, 0, mc_group.id, GFP_ATOMIC));
        if (err && net_ratelimit())
                printk(KERN_WARNING "send_openflow_skb: send failed: %d\n",
                       err);
        return err;
}

/* Generates a unique datapath id.  It incorporates the datapath index
 * and a hardware address, if available.  If not, it generates a random
 * one.
 */
static 
uint64_t gen_datapath_id(uint16_t dp_idx)
{
        uint64_t id;
        int i;
        struct net_device *dev;

        /* The top 16 bits are used to identify the datapath.  The lower 48 bits
         * use an interface address.  */
        id = (uint64_t)dp_idx << 48;
        if ((dev = dev_get_by_name(&init_net, "ctl0")) 
                        || (dev = dev_get_by_name(&init_net, "eth0"))) {
                for (i=0; i<ETH_ALEN; i++) {
                        id |= (uint64_t)dev->dev_addr[i] << (8*(ETH_ALEN-1 - i));
                }
                dev_put(dev);
        } else {
                /* Randomly choose the lower 48 bits if we cannot find an
                 * address and mark the most significant bit to indicate that
                 * this was randomly generated. */
                uint8_t rand[ETH_ALEN];
                get_random_bytes(rand, ETH_ALEN);
                id |= (uint64_t)1 << 63;
                for (i=0; i<ETH_ALEN; i++) {
                        id |= (uint64_t)rand[i] << (8*(ETH_ALEN-1 - i));
                }
        }

        return id;
}

/* Creates a new datapath numbered 'dp_idx'.  Returns 0 for success or a
 * negative error code.
 *
 * Not called with any locks. */
static int new_dp(int dp_idx)
{
        struct datapath *dp;
        int err;

        if (dp_idx < 0 || dp_idx >= DP_MAX)
                return -EINVAL;

        if (!try_module_get(THIS_MODULE))
                return -ENODEV;

        mutex_lock(&dp_mutex);
        dp = rcu_dereference(dps[dp_idx]);
        if (dp != NULL) {
                err = -EEXIST;
                goto err_unlock;
        }

        err = -ENOMEM;
        dp = kzalloc(sizeof *dp, GFP_KERNEL);
        if (dp == NULL)
                goto err_unlock;

        dp->dp_idx = dp_idx;
        dp->id = gen_datapath_id(dp_idx);
        dp->chain = chain_create(dp);
        if (dp->chain == NULL)
                goto err_free_dp;
        INIT_LIST_HEAD(&dp->port_list);

#if 0
        /* Setup our "of" device */
        dp->dev.priv = dp;
        rtnl_lock();
        err = dp_dev_setup(&dp->dev);
        rtnl_unlock();
        if (err != 0) 
                printk("datapath: problem setting up 'of' device\n");
#endif

        dp->flags = 0;
        dp->miss_send_len = OFP_DEFAULT_MISS_SEND_LEN;

        dp->dp_task = kthread_run(dp_maint_func, dp, "dp%d", dp_idx);
        if (IS_ERR(dp->dp_task))
                goto err_free_dp;

        rcu_assign_pointer(dps[dp_idx], dp);
        mutex_unlock(&dp_mutex);

        return 0;

err_free_dp:
        kfree(dp);
err_unlock:
        mutex_unlock(&dp_mutex);
        module_put(THIS_MODULE);
                return err;
}

/* Find and return a free port number under 'dp'.  Called under dp_mutex. */
static int find_portno(struct datapath *dp)
{
        int i;
        for (i = 0; i < OFPP_MAX; i++)
                if (dp->ports[i] == NULL)
                        return i;
        return -EXFULL;
}

static struct net_bridge_port *new_nbp(struct datapath *dp,
                                                                           struct net_device *dev)
{
        struct net_bridge_port *p;
        int port_no;

        port_no = find_portno(dp);
        if (port_no < 0)
                return ERR_PTR(port_no);

        p = kzalloc(sizeof(*p), GFP_KERNEL);
        if (p == NULL)
                return ERR_PTR(-ENOMEM);

        p->dp = dp;
        dev_hold(dev);
        p->dev = dev;
        p->port_no = port_no;

        return p;
}

/* Called with dp_mutex. */
int add_switch_port(struct datapath *dp, struct net_device *dev)
{
        struct net_bridge_port *p;

        if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
                return -EINVAL;

        if (dev->br_port != NULL)
                return -EBUSY;

        p = new_nbp(dp, dev);
        if (IS_ERR(p))
                return PTR_ERR(p);

        dev_hold(dev);
        rcu_assign_pointer(dev->br_port, p);
        rtnl_lock();
        dev_set_promiscuity(dev, 1);
        rtnl_unlock();

        rcu_assign_pointer(dp->ports[p->port_no], p);
        list_add_rcu(&p->node, &dp->port_list);

        /* Notify the ctlpath that this port has been added */
        send_port_status(p, OFPPR_ADD);

        return 0;
}

/* Delete 'p' from switch.
 * Called with dp_mutex. */
static int del_switch_port(struct net_bridge_port *p)
{
        /* First drop references to device. */
        rtnl_lock();
        dev_set_promiscuity(p->dev, -1);
        rtnl_unlock();
        list_del_rcu(&p->node);
        rcu_assign_pointer(p->dp->ports[p->port_no], NULL);
        rcu_assign_pointer(p->dev->br_port, NULL);

        /* Then wait until no one is still using it, and destroy it. */
        synchronize_rcu();

        /* Notify the ctlpath that this port no longer exists */
        send_port_status(p, OFPPR_DELETE);

        dev_put(p->dev);
        kfree(p);

        return 0;
}

/* Called with dp_mutex. */
static void del_dp(struct datapath *dp)
{
        struct net_bridge_port *p, *n;

#if 0
        /* Unregister the "of" device of this dp */
        rtnl_lock();
        unregister_netdevice(&dp->dev);
        rtnl_unlock();
#endif

        kthread_stop(dp->dp_task);

        /* Drop references to DP. */
        list_for_each_entry_safe (p, n, &dp->port_list, node)
                del_switch_port(p);
        rcu_assign_pointer(dps[dp->dp_idx], NULL);

        /* Wait until no longer in use, then destroy it. */
        synchronize_rcu();
        chain_destroy(dp->chain);
        kfree(dp);
        module_put(THIS_MODULE);
}

static int dp_maint_func(void *data)
{
        struct datapath *dp = (struct datapath *) data;

        while (!kthread_should_stop()) {
                chain_timeout(dp->chain);
                msleep_interruptible(MAINT_SLEEP_MSECS);
        }
                
        return 0;
}

static void
do_port_input(struct net_bridge_port *p, struct sk_buff *skb) 
{
        /* Push the Ethernet header back on. */
        if (skb->protocol == htons(ETH_P_8021Q))
                skb_push(skb, VLAN_ETH_HLEN);
        else
                skb_push(skb, ETH_HLEN);
        fwd_port_input(p->dp->chain, skb, p->port_no);
}

/*
 * Used as br_handle_frame_hook.  (Cannot run bridge at the same time, even on
 * different set of devices!)
 */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
/* Called with rcu_read_lock. */
static struct sk_buff *dp_frame_hook(struct net_bridge_port *p,
                                         struct sk_buff *skb)
{
        do_port_input(p, skb);
        return NULL;
}
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
static int dp_frame_hook(struct net_bridge_port *p, struct sk_buff **pskb)
{
        do_port_input(p, *pskb);
        return 1;
}
#else
/* NB: This has only been tested on 2.4.35 */

/* Called without any locks (?) */
static void dp_frame_hook(struct sk_buff *skb)
{
        struct net_bridge_port *p = skb->dev->br_port;
        if (p) {
                rcu_read_lock();
                do_port_input(p, skb);
                rcu_read_unlock();
        } else
                kfree_skb(skb);
}
#endif

/* Forwarding output path.
 * Based on net/bridge/br_forward.c. */

/* Don't forward packets to originating port.  If we're flooding,
 * then don't send out ports with flooding disabled.
 */
static inline int should_deliver(const struct net_bridge_port *p,
                        const struct sk_buff *skb, int flood)
{
        if (skb->dev == p->dev)
                return 0;

        if (flood && (p->flags & BRIDGE_PORT_NO_FLOOD))
                return 0;

        return 1;
}

static inline unsigned packet_length(const struct sk_buff *skb)
{
        int length = skb->len - ETH_HLEN;
        if (skb->protocol == htons(ETH_P_8021Q))
                length -= VLAN_HLEN;
        return length;
}

/* Send packets out all the ports except the originating one.  If the
 * "flood" argument is set, only send along the minimum spanning tree.
 */
static int
output_all(struct datapath *dp, struct sk_buff *skb, int flood)
{
        struct net_bridge_port *p;
        int prev_port;

        prev_port = -1;
        list_for_each_entry_rcu (p, &dp->port_list, node) {
                if (!should_deliver(p, skb, flood))
                        continue;
                if (prev_port != -1) {
                        struct sk_buff *clone = skb_clone(skb, GFP_ATOMIC);
                        if (!clone) {
                                kfree_skb(skb);
                                return -ENOMEM;
                        }
                        dp_output_port(dp, clone, prev_port); 
                }
                prev_port = p->port_no;
        }
        if (prev_port != -1)
                dp_output_port(dp, skb, prev_port);
        else
                kfree_skb(skb);

        return 0;
}

/* Marks 'skb' as having originated from 'in_port' in 'dp'.
   FIXME: how are devices reference counted? */
int dp_set_origin(struct datapath *dp, uint16_t in_port,
                           struct sk_buff *skb)
{
        if (in_port < OFPP_MAX && dp->ports[in_port]) {
                skb->dev = dp->ports[in_port]->dev;
                return 0;
        }
        return -ENOENT;
}

/* Takes ownership of 'skb' and transmits it to 'out_port' on 'dp'.
 */
int dp_output_port(struct datapath *dp, struct sk_buff *skb, int out_port)
{
        struct net_bridge_port *p;
        int len = skb->len;

        BUG_ON(!skb);
        if (out_port == OFPP_FLOOD)
                return output_all(dp, skb, 1);
        else if (out_port == OFPP_ALL)
                return output_all(dp, skb, 0);
        else if (out_port == OFPP_CONTROLLER)
                return dp_output_control(dp, skb, fwd_save_skb(skb), 0,
                                                  OFPR_ACTION);
        else if (out_port == OFPP_TABLE) {
                struct sw_flow_key key;
                struct sw_flow *flow;

                flow_extract(skb, skb->dev->br_port->port_no, &key);
                flow = chain_lookup(dp->chain, &key);
                if (likely(flow != NULL)) {
                        flow_used(flow, skb);
                        execute_actions(dp, skb, &key, flow->actions, flow->n_actions);
                        return 0;
                }
                return -ESRCH;
        } else if (out_port >= OFPP_MAX)
                goto bad_port;

        p = dp->ports[out_port];
        if (p == NULL)
                goto bad_port;

        skb->dev = p->dev;
        if (packet_length(skb) > skb->dev->mtu) {
                printk("dropped over-mtu packet: %d > %d\n",
                                        packet_length(skb), skb->dev->mtu);
                kfree_skb(skb);
                return -E2BIG;
        }

        dev_queue_xmit(skb);

        return len;

bad_port:
        kfree_skb(skb);
        if (net_ratelimit())
                printk("can't forward to bad port %d\n", out_port);
        return -ENOENT;
}

/* Takes ownership of 'skb' and transmits it to 'dp''s control path.  If
 * 'buffer_id' != -1, then only the first 64 bytes of 'skb' are sent;
 * otherwise, all of 'skb' is sent.  'reason' indicates why 'skb' is being
 * sent. 'max_len' sets the maximum number of bytes that the caller
 * wants to be sent; a value of 0 indicates the entire packet should be
 * sent. */
int
dp_output_control(struct datapath *dp, struct sk_buff *skb,
                           uint32_t buffer_id, size_t max_len, int reason)
{
        /* FIXME?  Can we avoid creating a new skbuff in the case where we
         * forward the whole packet? */
        struct sk_buff *f_skb;
        struct ofp_packet_in *opi;
        size_t fwd_len, opi_len;
        int err;

        fwd_len = skb->len;
        if ((buffer_id != (uint32_t) -1) && max_len)
                fwd_len = min(fwd_len, max_len);

        opi_len = offsetof(struct ofp_packet_in, data) + fwd_len;
        opi = alloc_openflow_skb(dp, opi_len, OFPT_PACKET_IN, NULL, &f_skb);
        if (!opi) {
                err = -ENOMEM;
                goto out;
        }
        opi->buffer_id      = htonl(buffer_id);
        opi->total_len      = htons(skb->len);
        opi->in_port        = htons(skb->dev->br_port->port_no);
        opi->reason         = reason;
        opi->pad            = 0;
        memcpy(opi->data, skb_mac_header(skb), fwd_len);
        err = send_openflow_skb(f_skb, NULL);

out:
        kfree_skb(skb);
        return err;
}

static void fill_port_desc(struct net_bridge_port *p, struct ofp_phy_port *desc)
{
        desc->port_no = htons(p->port_no);
        strncpy(desc->name, p->dev->name, OFP_MAX_PORT_NAME_LEN);
        desc->name[OFP_MAX_PORT_NAME_LEN-1] = '\0';
        memcpy(desc->hw_addr, p->dev->dev_addr, ETH_ALEN);
        desc->flags = htonl(p->flags);
        desc->features = 0;
        desc->speed = 0;

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,24)
        if (p->dev->ethtool_ops && p->dev->ethtool_ops->get_settings) {
                struct ethtool_cmd ecmd = { .cmd = ETHTOOL_GSET };

                if (!p->dev->ethtool_ops->get_settings(p->dev, &ecmd)) {
                        if (ecmd.supported & SUPPORTED_10baseT_Half) 
                                desc->features |= OFPPF_10MB_HD;
                        if (ecmd.supported & SUPPORTED_10baseT_Full)
                                desc->features |= OFPPF_10MB_FD;
                        if (ecmd.supported & SUPPORTED_100baseT_Half) 
                                desc->features |= OFPPF_100MB_HD;
                        if (ecmd.supported & SUPPORTED_100baseT_Full)
                                desc->features |= OFPPF_100MB_FD;
                        if (ecmd.supported & SUPPORTED_1000baseT_Half)
                                desc->features |= OFPPF_1GB_HD;
                        if (ecmd.supported & SUPPORTED_1000baseT_Full)
                                desc->features |= OFPPF_1GB_FD;
                        /* 10Gbps half-duplex doesn't exist... */
                        if (ecmd.supported & SUPPORTED_10000baseT_Full)
                                desc->features |= OFPPF_10GB_FD;

                        desc->features = htonl(desc->features);
                        desc->speed = htonl(ecmd.speed);
                }
        }
#endif
}

static int 
fill_features_reply(struct datapath *dp, struct ofp_switch_features *ofr)
{
        struct net_bridge_port *p;
        int port_count = 0;

        ofr->datapath_id    = cpu_to_be64(dp->id); 

        ofr->n_exact        = htonl(2 * TABLE_HASH_MAX_FLOWS);
        ofr->n_compression  = 0;                                           /* Not supported */
        ofr->n_general      = htonl(TABLE_LINEAR_MAX_FLOWS);
        ofr->buffer_mb      = htonl(UINT32_MAX);
        ofr->n_buffers      = htonl(N_PKT_BUFFERS);
        ofr->capabilities   = htonl(OFP_SUPPORTED_CAPABILITIES);
        ofr->actions        = htonl(OFP_SUPPORTED_ACTIONS);

        list_for_each_entry_rcu (p, &dp->port_list, node) {
                fill_port_desc(p, &ofr->ports[port_count]);
                port_count++;
        }

        return port_count;
}

int
dp_send_features_reply(struct datapath *dp, const struct sender *sender)
{
        struct sk_buff *skb;
        struct ofp_switch_features *ofr;
        size_t ofr_len, port_max_len;
        int port_count;

        /* Overallocate. */
        port_max_len = sizeof(struct ofp_phy_port) * OFPP_MAX;
        ofr = alloc_openflow_skb(dp, sizeof(*ofr) + port_max_len,
                                 OFPT_FEATURES_REPLY, sender, &skb);
        if (!ofr)
                return -ENOMEM;

        /* Fill. */
        port_count = fill_features_reply(dp, ofr);

        /* Shrink to fit. */
        ofr_len = sizeof(*ofr) + (sizeof(struct ofp_phy_port) * port_count);
        resize_openflow_skb(skb, &ofr->header, ofr_len);
        return send_openflow_skb(skb, sender);
}

int
dp_send_config_reply(struct datapath *dp, const struct sender *sender)
{
        struct sk_buff *skb;
        struct ofp_switch_config *osc;

        osc = alloc_openflow_skb(dp, sizeof *osc, OFPT_GET_CONFIG_REPLY, sender,
                                 &skb);
        if (!osc)
                return -ENOMEM;

        osc->flags = htons(dp->flags);
        osc->miss_send_len = htons(dp->miss_send_len);

        return send_openflow_skb(skb, sender);
}

int
dp_update_port_flags(struct datapath *dp, const struct ofp_phy_port *opp)
{
        struct net_bridge_port *p;

        p = dp->ports[htons(opp->port_no)];

        /* Make sure the port id hasn't changed since this was sent */
        if (!p || memcmp(opp->hw_addr, p->dev->dev_addr, ETH_ALEN) != 0) 
                return -1;
        
        p->flags = htonl(opp->flags);

        return 0;
}


static int
send_port_status(struct net_bridge_port *p, uint8_t status)
{
        struct sk_buff *skb;
        struct ofp_port_status *ops;

        ops = alloc_openflow_skb(p->dp, sizeof *ops, OFPT_PORT_STATUS, NULL,
                                 &skb);
        if (!ops)
                return -ENOMEM;
        ops->reason = status;
        memset(ops->pad, 0, sizeof ops->pad);
        fill_port_desc(p, &ops->desc);

        return send_openflow_skb(skb, NULL);
}

int 
dp_send_flow_expired(struct datapath *dp, struct sw_flow *flow)
{
        struct sk_buff *skb;
        struct ofp_flow_expired *ofe;
        unsigned long duration_j;

        ofe = alloc_openflow_skb(dp, sizeof *ofe, OFPT_FLOW_EXPIRED, 0, &skb);
        if (!ofe)
                return -ENOMEM;

        flow_fill_match(&ofe->match, &flow->key);

        memset(ofe->pad, 0, sizeof ofe->pad);
        ofe->priority = htons(flow->priority);

        duration_j = (flow->timeout - HZ * flow->max_idle) - flow->init_time;
        ofe->duration     = htonl(duration_j / HZ);
        ofe->packet_count = cpu_to_be64(flow->packet_count);
        ofe->byte_count   = cpu_to_be64(flow->byte_count);

        return send_openflow_skb(skb, NULL);
}
EXPORT_SYMBOL(dp_send_flow_expired);

int
dp_send_error_msg(struct datapath *dp, const struct sender *sender, 
                uint16_t type, uint16_t code, const uint8_t *data, size_t len)
{
        struct sk_buff *skb;
        struct ofp_error_msg *oem;


        oem = alloc_openflow_skb(dp, sizeof(*oem)+len, OFPT_ERROR_MSG, 
                        sender, &skb);
        if (!oem)
                return -ENOMEM;

        oem->type = htons(type);
        oem->code = htons(code);
        memcpy(oem->data, data, len);

        return send_openflow_skb(skb, sender);
}

/* Generic Netlink interface.
 *
 * See netlink(7) for an introduction to netlink.  See
 * http://linux-net.osdl.org/index.php/Netlink for more information and
 * pointers on how to work with netlink and Generic Netlink in the kernel and
 * in userspace. */

static struct genl_family dp_genl_family = {
        .id = GENL_ID_GENERATE,
        .hdrsize = 0,
        .name = DP_GENL_FAMILY_NAME,
        .version = 1,
        .maxattr = DP_GENL_A_MAX,
};

/* Attribute policy: what each attribute may contain.  */
static struct nla_policy dp_genl_policy[DP_GENL_A_MAX + 1] = {
        [DP_GENL_A_DP_IDX] = { .type = NLA_U32 },
        [DP_GENL_A_MC_GROUP] = { .type = NLA_U32 },
        [DP_GENL_A_PORTNAME] = { .type = NLA_STRING }
};

static int dp_genl_add(struct sk_buff *skb, struct genl_info *info)
{
        if (!info->attrs[DP_GENL_A_DP_IDX])
                return -EINVAL;

        return new_dp(nla_get_u32(info->attrs[DP_GENL_A_DP_IDX]));
}

static struct genl_ops dp_genl_ops_add_dp = {
        .cmd = DP_GENL_C_ADD_DP,
        .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
        .policy = dp_genl_policy,
        .doit = dp_genl_add,
        .dumpit = NULL,
};

struct datapath *dp_get(int dp_idx)
{
        if (dp_idx < 0 || dp_idx > DP_MAX)
                return NULL;
        return rcu_dereference(dps[dp_idx]);
}

static int dp_genl_del(struct sk_buff *skb, struct genl_info *info)
{
        struct datapath *dp;
        int err;

        if (!info->attrs[DP_GENL_A_DP_IDX])
                return -EINVAL;

        mutex_lock(&dp_mutex);
        dp = dp_get(nla_get_u32((info->attrs[DP_GENL_A_DP_IDX])));
        if (!dp)
                err = -ENOENT;
        else {
                del_dp(dp);
                err = 0;
        }
        mutex_unlock(&dp_mutex);
        return err;
}

static struct genl_ops dp_genl_ops_del_dp = {
        .cmd = DP_GENL_C_DEL_DP,
        .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
        .policy = dp_genl_policy,
        .doit = dp_genl_del,
        .dumpit = NULL,
};

/* Queries a datapath for related information.  Currently the only relevant
 * information is the datapath's multicast group ID.  Really we want one
 * multicast group per datapath, but because of locking issues[*] we can't
 * easily get one.  Thus, every datapath will currently return the same
 * global multicast group ID, but in the future it would be nice to fix that.
 *
 * [*] dp_genl_add, to add a new datapath, is called under the genl_lock
 *       mutex, and genl_register_mc_group, called to acquire a new multicast
 *       group ID, also acquires genl_lock, thus deadlock.
 */
static int dp_genl_query(struct sk_buff *skb, struct genl_info *info)
{
        struct datapath *dp;
        struct sk_buff *ans_skb = NULL;
        int dp_idx;
        int err = -ENOMEM;

        if (!info->attrs[DP_GENL_A_DP_IDX])
                return -EINVAL;

        rcu_read_lock();
        dp_idx = nla_get_u32((info->attrs[DP_GENL_A_DP_IDX]));
        dp = dp_get(dp_idx);
        if (!dp)
                err = -ENOENT;
        else {
                void *data;
                ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
                if (!ans_skb) {
                        err = -ENOMEM;
                        goto err;
                }
                data = genlmsg_put_reply(ans_skb, info, &dp_genl_family,
                                         0, DP_GENL_C_QUERY_DP);
                if (data == NULL) {
                        err = -ENOMEM;
                        goto err;
                }
                NLA_PUT_U32(ans_skb, DP_GENL_A_DP_IDX, dp_idx);
                NLA_PUT_U32(ans_skb, DP_GENL_A_MC_GROUP, mc_group.id);

                genlmsg_end(ans_skb, data);
                err = genlmsg_reply(ans_skb, info);
                if (!err)
                        ans_skb = NULL;
        }
err:
nla_put_failure:
        if (ans_skb)
                kfree_skb(ans_skb);
        rcu_read_unlock();
        return err;
}

static struct genl_ops dp_genl_ops_query_dp = {
        .cmd = DP_GENL_C_QUERY_DP,
        .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
        .policy = dp_genl_policy,
        .doit = dp_genl_query,
        .dumpit = NULL,
};

static int dp_genl_add_del_port(struct sk_buff *skb, struct genl_info *info)
{
        struct datapath *dp;
        struct net_device *port;
        int err;

        if (!info->attrs[DP_GENL_A_DP_IDX] || !info->attrs[DP_GENL_A_PORTNAME])
                return -EINVAL;

        /* Get datapath. */
        mutex_lock(&dp_mutex);
        dp = dp_get(nla_get_u32(info->attrs[DP_GENL_A_DP_IDX]));
        if (!dp) {
                err = -ENOENT;
                goto out;
        }

        /* Get interface to add/remove. */
        port = dev_get_by_name(&init_net, 
                        nla_data(info->attrs[DP_GENL_A_PORTNAME]));
        if (!port) {
                err = -ENOENT;
                goto out;
        }

        /* Execute operation. */
        if (info->genlhdr->cmd == DP_GENL_C_ADD_PORT)
                err = add_switch_port(dp, port);
        else {
                if (port->br_port == NULL || port->br_port->dp != dp) {
                        err = -ENOENT;
                        goto out_put;
                }
                err = del_switch_port(port->br_port);
        }

out_put:
        dev_put(port);
out:
        mutex_unlock(&dp_mutex);
        return err;
}

static struct genl_ops dp_genl_ops_add_port = {
        .cmd = DP_GENL_C_ADD_PORT,
        .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
        .policy = dp_genl_policy,
        .doit = dp_genl_add_del_port,
        .dumpit = NULL,
};

static struct genl_ops dp_genl_ops_del_port = {
        .cmd = DP_GENL_C_DEL_PORT,
        .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
        .policy = dp_genl_policy,
        .doit = dp_genl_add_del_port,
        .dumpit = NULL,
};

static int dp_genl_openflow(struct sk_buff *skb, struct genl_info *info)
{
        struct nlattr *va = info->attrs[DP_GENL_A_OPENFLOW];
        struct datapath *dp;
        struct ofp_header *oh;
        struct sender sender;
        int err;

        if (!info->attrs[DP_GENL_A_DP_IDX] || !va)
                return -EINVAL;

        rcu_read_lock();
        dp = dp_get(nla_get_u32(info->attrs[DP_GENL_A_DP_IDX]));
        if (!dp) {
                err = -ENOENT;
                goto out;
        }

        if (nla_len(va) < sizeof(struct ofp_header)) {
                err = -EINVAL;
                goto out;
        }
        oh = nla_data(va);

        sender.xid = oh->xid;
        sender.pid = info->snd_pid;
        sender.seq = info->snd_seq;
        err = fwd_control_input(dp->chain, &sender, nla_data(va), nla_len(va));

out:
        rcu_read_unlock();
        return err;
}

static struct nla_policy dp_genl_openflow_policy[DP_GENL_A_MAX + 1] = {
        [DP_GENL_A_DP_IDX] = { .type = NLA_U32 },
};

struct flow_stats_state {
        int table_idx;
        struct sw_table_position position;
        const struct ofp_flow_stats_request *rq;

        void *body;
        int bytes_used, bytes_allocated;
};

static int flow_stats_init(struct datapath *dp, const void *body, int body_len,
                           void **state)
{
        const struct ofp_flow_stats_request *fsr = body;
        struct flow_stats_state *s = kmalloc(sizeof *s, GFP_ATOMIC);
        if (!s)
                return -ENOMEM;
        s->table_idx = fsr->table_id == 0xff ? 0 : fsr->table_id;
        memset(&s->position, 0, sizeof s->position);
        s->rq = fsr;
        *state = s;
        return 0;
}

static int flow_stats_dump_callback(struct sw_flow *flow, void *private)
{
        struct flow_stats_state *s = private;
        struct ofp_flow_stats *ofs;
        int actions_length;
        int length;

        actions_length = sizeof *ofs->actions * flow->n_actions;
        length = sizeof *ofs + sizeof *ofs->actions * flow->n_actions;
        if (length + s->bytes_used > s->bytes_allocated)
                return 1;

        ofs = s->body + s->bytes_used;
        ofs->length          = htons(length);
        ofs->table_id        = s->table_idx;
        ofs->pad             = 0;
        ofs->match.wildcards = htons(flow->key.wildcards);
        ofs->match.in_port   = flow->key.in_port;
        memcpy(ofs->match.dl_src, flow->key.dl_src, ETH_ALEN);
        memcpy(ofs->match.dl_dst, flow->key.dl_dst, ETH_ALEN);
        ofs->match.dl_vlan   = flow->key.dl_vlan;
        ofs->match.dl_type   = flow->key.dl_type;
        ofs->match.nw_src    = flow->key.nw_src;
        ofs->match.nw_dst    = flow->key.nw_dst;
        ofs->match.nw_proto  = flow->key.nw_proto;
        memset(ofs->match.pad, 0, sizeof ofs->match.pad);
        ofs->match.tp_src    = flow->key.tp_src;
        ofs->match.tp_dst    = flow->key.tp_dst;
        ofs->duration        = htonl((jiffies - flow->init_time) / HZ);
        ofs->packet_count    = cpu_to_be64(flow->packet_count);
        ofs->byte_count      = cpu_to_be64(flow->byte_count);
        ofs->priority        = htons(flow->priority);
        ofs->max_idle        = htons(flow->max_idle);
        memcpy(ofs->actions, flow->actions, actions_length);

        s->bytes_used += length;
        return 0;
}

static int flow_stats_dump(struct datapath *dp, void *state,
                           void *body, int *body_len)
{
        struct flow_stats_state *s = state;
        struct sw_flow_key match_key;
        int error = 0;

        s->bytes_used = 0;
        s->bytes_allocated = *body_len;
        s->body = body;

        flow_extract_match(&match_key, &s->rq->match);
        while (s->table_idx < dp->chain->n_tables
               && (s->rq->table_id == 0xff || s->rq->table_id == s->table_idx))
        {
                struct sw_table *table = dp->chain->tables[s->table_idx];

                error = table->iterate(table, &match_key, &s->position,
                                       flow_stats_dump_callback, s);
                if (error)
                        break;

                s->table_idx++;
                memset(&s->position, 0, sizeof s->position);
        }
        *body_len = s->bytes_used;

        /* If error is 0, we're done.
         * Otherwise, if some bytes were used, there are more flows to come.
         * Otherwise, we were not able to fit even a single flow in the body,
         * which indicates that we have a single flow with too many actions to
         * fit.  We won't ever make any progress at that rate, so give up. */
        return !error ? 0 : s->bytes_used ? 1 : -ENOMEM;
}

static void flow_stats_done(void *state)
{
        kfree(state);
}

static int aggregate_stats_init(struct datapath *dp,
                                const void *body, int body_len,
                                void **state)
{
        *state = (void *)body;
        return 0;
}

static int aggregate_stats_dump_callback(struct sw_flow *flow, void *private)
{
        struct ofp_aggregate_stats_reply *rpy = private;
        rpy->packet_count += flow->packet_count;
        rpy->byte_count += flow->byte_count;
        rpy->flow_count++;
        return 0;
}

static int aggregate_stats_dump(struct datapath *dp, void *state,
                                void *body, int *body_len)
{
        struct ofp_aggregate_stats_request *rq = state;
        struct ofp_aggregate_stats_reply *rpy;
        struct sw_table_position position;
        struct sw_flow_key match_key;
        int table_idx;

        if (*body_len < sizeof *rpy)
                return -ENOBUFS;
        rpy = body;
        *body_len = sizeof *rpy;

        memset(rpy, 0, sizeof *rpy);

        flow_extract_match(&match_key, &rq->match);
        table_idx = rq->table_id == 0xff ? 0 : rq->table_id;
        memset(&position, 0, sizeof position);
        while (table_idx < dp->chain->n_tables
               && (rq->table_id == 0xff || rq->table_id == table_idx))
        {
                struct sw_table *table = dp->chain->tables[table_idx];
                int error;

                error = table->iterate(table, &match_key, &position,
                                       aggregate_stats_dump_callback, rpy);
                if (error)
                        return error;

                table_idx++;
                memset(&position, 0, sizeof position);
        }

        rpy->packet_count = cpu_to_be64(rpy->packet_count);
        rpy->byte_count = cpu_to_be64(rpy->byte_count);
        rpy->flow_count = htonl(rpy->flow_count);
        return 0;
}

static int table_stats_dump(struct datapath *dp, void *state,
                            void *body, int *body_len)
{
        struct ofp_table_stats *ots;
        int nbytes = dp->chain->n_tables * sizeof *ots;
        int i;
        if (nbytes > *body_len)
                return -ENOBUFS;
        *body_len = nbytes;
        for (i = 0, ots = body; i < dp->chain->n_tables; i++, ots++) {
                struct sw_table_stats stats;
                dp->chain->tables[i]->stats(dp->chain->tables[i], &stats);
                strncpy(ots->name, stats.name, sizeof ots->name);
                ots->table_id = i;
                memset(ots->pad, 0, sizeof ots->pad);
                ots->max_entries = htonl(stats.max_flows);
                ots->active_count = htonl(stats.n_flows);
                ots->matched_count = cpu_to_be64(0); /* FIXME */
        }
        return 0;
}

struct port_stats_state {
        int port;
};

static int port_stats_init(struct datapath *dp, const void *body, int body_len,
                           void **state)
{
        struct port_stats_state *s = kmalloc(sizeof *s, GFP_ATOMIC);
        if (!s)
                return -ENOMEM;
        s->port = 0;
        *state = s;
        return 0;
}

static int port_stats_dump(struct datapath *dp, void *state,
                           void *body, int *body_len)
{
        struct port_stats_state *s = state;
        struct ofp_port_stats *ops;
        int n_ports, max_ports;
        int i;

        max_ports = *body_len / sizeof *ops;
        if (!max_ports)
                return -ENOMEM;
        ops = body;

        n_ports = 0;
        for (i = s->port; i < OFPP_MAX && n_ports < max_ports; i++) {
                struct net_bridge_port *p = dp->ports[i];
                struct net_device_stats *stats;
                if (!p)
                        continue;
                stats = p->dev->get_stats(p->dev);
                ops->port_no = htons(p->port_no);
                memset(ops->pad, 0, sizeof ops->pad);
                ops->rx_count = cpu_to_be64(stats->rx_packets);
                ops->tx_count = cpu_to_be64(stats->tx_packets);
                ops->drop_count = cpu_to_be64(stats->rx_dropped
                                              + stats->tx_dropped);
                n_ports++;
                ops++;
        }
        s->port = i;
        *body_len = n_ports * sizeof *ops;
        return n_ports >= max_ports;
}

static void port_stats_done(void *state)
{
        kfree(state);
}

struct stats_type {
        /* Minimum and maximum acceptable number of bytes in body member of
         * struct ofp_stats_request. */
        size_t min_body, max_body;

        /* Prepares to dump some kind of statistics on 'dp'.  'body' and
         * 'body_len' are the 'body' member of the struct ofp_stats_request.
         * Returns zero if successful, otherwise a negative error code.
         * May initialize '*state' to state information.  May be null if no
         * initialization is required.*/
        int (*init)(struct datapath *dp, const void *body, int body_len,
                    void **state);

        /* Dumps statistics for 'dp' into the '*body_len' bytes at 'body', and
         * modifies '*body_len' to reflect the number of bytes actually used.
         * ('body' will be transmitted as the 'body' member of struct
         * ofp_stats_reply.) */
        int (*dump)(struct datapath *dp, void *state,
                    void *body, int *body_len);

        /* Cleans any state created by the init or dump functions.  May be null
         * if no cleanup is required. */
        void (*done)(void *state);
};

static const struct stats_type stats[] = {
        [OFPST_FLOW] = {
                sizeof(struct ofp_flow_stats_request),
                sizeof(struct ofp_flow_stats_request),
                flow_stats_init,
                flow_stats_dump,
                flow_stats_done
        },
        [OFPST_AGGREGATE] = {
                sizeof(struct ofp_aggregate_stats_request),
                sizeof(struct ofp_aggregate_stats_request),
                aggregate_stats_init,
                aggregate_stats_dump,
                NULL
        },
        [OFPST_TABLE] = {
                0,
                0,
                NULL,
                table_stats_dump,
                NULL
        },
        [OFPST_PORT] = {
                0,
                0,
                port_stats_init,
                port_stats_dump,
                port_stats_done
        },
};

static int
dp_genl_openflow_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct datapath *dp;
        struct sender sender;
        const struct stats_type *s;
        struct ofp_stats_reply *osr;
        int dp_idx;
        int max_openflow_len, body_len;
        void *body;
        int err;

        /* Set up the cleanup function for this dump.  Linux 2.6.20 and later
         * support setting up cleanup functions via the .doneit member of
         * struct genl_ops.  This kluge supports earlier versions also. */
        cb->done = dp_genl_openflow_done;

        rcu_read_lock();
        if (!cb->args[0]) {
                struct nlattr *attrs[DP_GENL_A_MAX + 1];
                struct ofp_stats_request *rq;
                struct nlattr *va;
                size_t len, body_len;
                int type;

                err = nlmsg_parse(cb->nlh, GENL_HDRLEN, attrs, DP_GENL_A_MAX,
                                  dp_genl_openflow_policy);
                if (err < 0)
                        return err;

                err = -EINVAL;

                if (!attrs[DP_GENL_A_DP_IDX])
                        goto out;
                dp_idx = nla_get_u16(attrs[DP_GENL_A_DP_IDX]);
                dp = dp_get(dp_idx);
                if (!dp) {
                        err = -ENOENT;
                        goto out;
                }

                va = attrs[DP_GENL_A_OPENFLOW];
                len = nla_len(va);
                if (!va || len < sizeof *rq)
                        goto out;

                rq = nla_data(va);
                type = ntohs(rq->type);
                if (rq->header.version != OFP_VERSION
                    || rq->header.type != OFPT_STATS_REQUEST
                    || ntohs(rq->header.length) != len
                    || type >= ARRAY_SIZE(stats)
                    || !stats[type].dump)
                        goto out;

                s = &stats[type];
                body_len = len - offsetof(struct ofp_stats_request, body);
                if (body_len < s->min_body || body_len > s->max_body)
                        goto out;

                cb->args[0] = 1;
                cb->args[1] = dp_idx;
                cb->args[2] = type;
                cb->args[3] = rq->header.xid;
                if (s->init) {
                        void *state;
                        err = s->init(dp, rq->body, body_len, &state);
                        if (err)
                                goto out;
                        cb->args[4] = (long) state;
                }
        } else if (cb->args[0] == 1) {
                dp_idx = cb->args[1];
                s = &stats[cb->args[2]];

                dp = dp_get(dp_idx);
                if (!dp) {
                        err = -ENOENT;
                        goto out;
                }
        } else {
                err = 0;
                goto out;
        }

        sender.xid = cb->args[3];
        sender.pid = NETLINK_CB(cb->skb).pid;
        sender.seq = cb->nlh->nlmsg_seq;

        osr = put_openflow_headers(dp, skb, OFPT_STATS_REPLY, &sender,
                                   &max_openflow_len);
        if (IS_ERR(osr)) {
                err = PTR_ERR(osr);
                goto out;
        }
        osr->type = htons(s - stats);
        osr->flags = 0;
        resize_openflow_skb(skb, &osr->header, max_openflow_len);
        body = osr->body;
        body_len = max_openflow_len - offsetof(struct ofp_stats_reply, body);

        err = s->dump(dp, (void *) cb->args[4], body, &body_len);
        if (err >= 0) {
                if (!err)
                        cb->args[0] = 2;
                else
                        osr->flags = ntohs(OFPSF_REPLY_MORE);
                resize_openflow_skb(skb, &osr->header,
                                    (offsetof(struct ofp_stats_reply, body)
                                     + body_len));
                err = skb->len;
        }

out:
        rcu_read_unlock();
        return err;
}

static int
dp_genl_openflow_done(struct netlink_callback *cb)
{
        if (cb->args[0]) {
                const struct stats_type *s = &stats[cb->args[2]];
                if (s->done)
                        s->done((void *) cb->args[4]);
        }
        return 0;
}

static struct genl_ops dp_genl_ops_openflow = {
        .cmd = DP_GENL_C_OPENFLOW,
        .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
        .policy = dp_genl_openflow_policy,
        .doit = dp_genl_openflow,
        .dumpit = dp_genl_openflow_dumpit,
};

static struct nla_policy dp_genl_benchmark_policy[DP_GENL_A_MAX + 1] = {
        [DP_GENL_A_DP_IDX] = { .type = NLA_U32 },
        [DP_GENL_A_NPACKETS] = { .type = NLA_U32 },
        [DP_GENL_A_PSIZE] = { .type = NLA_U32 },
};

static struct genl_ops dp_genl_ops_benchmark_nl = {
        .cmd = DP_GENL_C_BENCHMARK_NL,
        .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
        .policy = dp_genl_benchmark_policy,
        .doit = dp_genl_benchmark_nl,
        .dumpit = NULL,
};

static struct genl_ops *dp_genl_all_ops[] = {
        /* Keep this operation first.  Generic Netlink dispatching
         * looks up operations with linear search, so we want it at the
         * front. */
        &dp_genl_ops_openflow,

        &dp_genl_ops_add_dp,
        &dp_genl_ops_del_dp,
        &dp_genl_ops_query_dp,
        &dp_genl_ops_add_port,
        &dp_genl_ops_del_port,
        &dp_genl_ops_benchmark_nl,
};

static int dp_init_netlink(void)
{
        int err;
        int i;

        err = genl_register_family(&dp_genl_family);
        if (err)
                return err;

        for (i = 0; i < ARRAY_SIZE(dp_genl_all_ops); i++) {
                err = genl_register_ops(&dp_genl_family, dp_genl_all_ops[i]);
                if (err)
                        goto err_unregister;
        }

        strcpy(mc_group.name, "openflow");
        err = genl_register_mc_group(&dp_genl_family, &mc_group);
        if (err < 0)
                goto err_unregister;

        return 0;

err_unregister:
        genl_unregister_family(&dp_genl_family);
                return err;
}

static void dp_uninit_netlink(void)
{
        genl_unregister_family(&dp_genl_family);
}

#define DRV_NAME                "openflow"
#define DRV_VERSION      VERSION
#define DRV_DESCRIPTION "OpenFlow switching datapath implementation"
#define DRV_COPYRIGHT   "Copyright (c) 2007, 2008 The Board of Trustees of The Leland Stanford Junior University"


static int __init dp_init(void)
{
        int err;

        printk(KERN_INFO DRV_NAME ": " DRV_DESCRIPTION "\n");
        printk(KERN_INFO DRV_NAME ": " VERSION" built on "__DATE__" "__TIME__"\n");
        printk(KERN_INFO DRV_NAME ": " DRV_COPYRIGHT "\n");

        err = flow_init();
        if (err)
                goto error;

        err = dp_init_netlink();
        if (err)
                goto error_flow_exit;

        /* Hook into callback used by the bridge to intercept packets.
         * Parasites we are. */
        if (br_handle_frame_hook)
                printk("openflow: hijacking bridge hook\n");
        br_handle_frame_hook = dp_frame_hook;

        return 0;

error_flow_exit:
        flow_exit();
error:
        printk(KERN_EMERG "openflow: failed to install!");
        return err;
}

static void dp_cleanup(void)
{
        fwd_exit();
        dp_uninit_netlink();
        flow_exit();
        br_handle_frame_hook = NULL;
}

module_init(dp_init);
module_exit(dp_cleanup);

MODULE_DESCRIPTION(DRV_DESCRIPTION);
MODULE_AUTHOR(DRV_COPYRIGHT);
MODULE_LICENSE("GPL");