datapath: Constify various function arguments

[mirror_ovs.git] / datapath / vport.c

/*
 * 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
 */

#include <linux/etherdevice.h>
#include <linux/if.h>
#include <linux/if_vlan.h>
#include <linux/jhash.h>
#include <linux/kconfig.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/rtnetlink.h>
#include <linux/compat.h>
#include <linux/version.h>
#include <net/net_namespace.h>

#include "datapath.h"
#include "gso.h"
#include "vport.h"
#include "vport-internal_dev.h"

static void ovs_vport_record_error(struct vport *,
                                   enum vport_err_type err_type);

/* List of statically compiled vport implementations.  Don't forget to also
 * add yours to the list at the bottom of vport.h. */
static const struct vport_ops *vport_ops_list[] = {
        &ovs_netdev_vport_ops,
        &ovs_internal_vport_ops,
        &ovs_geneve_vport_ops,
#if IS_ENABLED(CONFIG_NET_IPGRE_DEMUX)
        &ovs_gre_vport_ops,
        &ovs_gre64_vport_ops,
#endif
        &ovs_vxlan_vport_ops,
        &ovs_lisp_vport_ops,
};

/* Protected by RCU read lock for reading, ovs_mutex for writing. */
static struct hlist_head *dev_table;
#define VPORT_HASH_BUCKETS 1024

/**
 *      ovs_vport_init - initialize vport subsystem
 *
 * Called at module load time to initialize the vport subsystem.
 */
int ovs_vport_init(void)
{
        dev_table = kzalloc(VPORT_HASH_BUCKETS * sizeof(struct hlist_head),
                            GFP_KERNEL);
        if (!dev_table)
                return -ENOMEM;

        return 0;
}

/**
 *      ovs_vport_exit - shutdown vport subsystem
 *
 * Called at module exit time to shutdown the vport subsystem.
 */
void ovs_vport_exit(void)
{
        kfree(dev_table);
}

static struct hlist_head *hash_bucket(const struct net *net, const char *name)
{
        unsigned int hash = jhash(name, strlen(name), (unsigned long) net);
        return &dev_table[hash & (VPORT_HASH_BUCKETS - 1)];
}

/**
 *      ovs_vport_locate - find a port that has already been created
 *
 * @name: name of port to find
 *
 * Must be called with ovs or RCU read lock.
 */
struct vport *ovs_vport_locate(const struct net *net, const char *name)
{
        struct hlist_head *bucket = hash_bucket(net, name);
        struct vport *vport;

        hlist_for_each_entry_rcu(vport, bucket, hash_node)
                if (!strcmp(name, vport->ops->get_name(vport)) &&
                    net_eq(ovs_dp_get_net(vport->dp), net))
                        return vport;

        return NULL;
}

/**
 *      ovs_vport_alloc - allocate and initialize new vport
 *
 * @priv_size: Size of private data area to allocate.
 * @ops: vport device ops
 *
 * Allocate and initialize a new vport defined by @ops.  The vport will contain
 * a private data area of size @priv_size that can be accessed using
 * vport_priv().  vports that are no longer needed should be released with
 * ovs_vport_free().
 */
struct vport *ovs_vport_alloc(int priv_size, const struct vport_ops *ops,
                              const struct vport_parms *parms)
{
        struct vport *vport;
        size_t alloc_size;

        alloc_size = sizeof(struct vport);
        if (priv_size) {
                alloc_size = ALIGN(alloc_size, VPORT_ALIGN);
                alloc_size += priv_size;
        }

        vport = kzalloc(alloc_size, GFP_KERNEL);
        if (!vport)
                return ERR_PTR(-ENOMEM);

        vport->dp = parms->dp;
        vport->port_no = parms->port_no;
        vport->ops = ops;
        INIT_HLIST_NODE(&vport->dp_hash_node);

        if (ovs_vport_set_upcall_portids(vport, parms->upcall_portids)) {
                kfree(vport);
                return ERR_PTR(-EINVAL);
        }

        vport->percpu_stats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
        if (!vport->percpu_stats) {
                kfree(vport);
                return ERR_PTR(-ENOMEM);
        }

        return vport;
}

/**
 *      ovs_vport_free - uninitialize and free vport
 *
 * @vport: vport to free
 *
 * Frees a vport allocated with ovs_vport_alloc() when it is no longer needed.
 *
 * The caller must ensure that an RCU grace period has passed since the last
 * time @vport was in a datapath.
 */
void ovs_vport_free(struct vport *vport)
{
        kfree((struct vport_portids __force *)vport->upcall_portids);
        free_percpu(vport->percpu_stats);
        kfree(vport);
}

/**
 *      ovs_vport_add - add vport device (for kernel callers)
 *
 * @parms: Information about new vport.
 *
 * Creates a new vport with the specified configuration (which is dependent on
 * device type).  ovs_mutex must be held.
 */
struct vport *ovs_vport_add(const struct vport_parms *parms)
{
        struct vport *vport;
        int err = 0;
        int i;

        for (i = 0; i < ARRAY_SIZE(vport_ops_list); i++) {
                if (vport_ops_list[i]->type == parms->type) {
                        struct hlist_head *bucket;

                        vport = vport_ops_list[i]->create(parms);
                        if (IS_ERR(vport)) {
                                err = PTR_ERR(vport);
                                goto out;
                        }

                        bucket = hash_bucket(ovs_dp_get_net(vport->dp),
                                             vport->ops->get_name(vport));
                        hlist_add_head_rcu(&vport->hash_node, bucket);
                        return vport;
                }
        }

        err = -EAFNOSUPPORT;

out:
        return ERR_PTR(err);
}

/**
 *      ovs_vport_set_options - modify existing vport device (for kernel callers)
 *
 * @vport: vport to modify.
 * @options: New configuration.
 *
 * Modifies an existing device with the specified configuration (which is
 * dependent on device type).  ovs_mutex must be held.
 */
int ovs_vport_set_options(struct vport *vport, struct nlattr *options)
{
        if (!vport->ops->set_options)
                return -EOPNOTSUPP;
        return vport->ops->set_options(vport, options);
}

/**
 *      ovs_vport_del - delete existing vport device
 *
 * @vport: vport to delete.
 *
 * Detaches @vport from its datapath and destroys it.  It is possible to fail
 * for reasons such as lack of memory.  ovs_mutex must be held.
 */
void ovs_vport_del(struct vport *vport)
{
        ASSERT_OVSL();

        hlist_del_rcu(&vport->hash_node);
        vport->ops->destroy(vport);
}

/**
 *      ovs_vport_get_stats - retrieve device stats
 *
 * @vport: vport from which to retrieve the stats
 * @stats: location to store stats
 *
 * Retrieves transmit, receive, and error stats for the given device.
 *
 * Must be called with ovs_mutex or rcu_read_lock.
 */
void ovs_vport_get_stats(struct vport *vport, struct ovs_vport_stats *stats)
{
        int i;

        /* We potentially have two surces of stats that need to be
         * combined: those we have collected (split into err_stats and
         * percpu_stats), and device error stats from netdev->get_stats()
         * (for errors that happen downstream and therefore aren't
         * reported through our vport_record_error() function).
         * Stats from first source are reported by ovs over
         * OVS_VPORT_ATTR_STATS.
         * netdev-stats can be directly read over netlink-ioctl.
         */

        stats->rx_errors  = atomic_long_read(&vport->err_stats.rx_errors);
        stats->tx_errors  = atomic_long_read(&vport->err_stats.tx_errors);
        stats->tx_dropped = atomic_long_read(&vport->err_stats.tx_dropped);
        stats->rx_dropped = atomic_long_read(&vport->err_stats.rx_dropped);

        stats->rx_bytes         = 0;
        stats->rx_packets       = 0;
        stats->tx_bytes         = 0;
        stats->tx_packets       = 0;

        for_each_possible_cpu(i) {
                const struct pcpu_sw_netstats *percpu_stats;
                struct pcpu_sw_netstats local_stats;
                unsigned int start;

                percpu_stats = per_cpu_ptr(vport->percpu_stats, i);

                do {
                        start = u64_stats_fetch_begin_irq(&percpu_stats->syncp);
                        local_stats = *percpu_stats;
                } while (u64_stats_fetch_retry_irq(&percpu_stats->syncp, start));

                stats->rx_bytes         += local_stats.rx_bytes;
                stats->rx_packets       += local_stats.rx_packets;
                stats->tx_bytes         += local_stats.tx_bytes;
                stats->tx_packets       += local_stats.tx_packets;
        }
}

/**
 *      ovs_vport_get_options - retrieve device options
 *
 * @vport: vport from which to retrieve the options.
 * @skb: sk_buff where options should be appended.
 *
 * Retrieves the configuration of the given device, appending an
 * %OVS_VPORT_ATTR_OPTIONS attribute that in turn contains nested
 * vport-specific attributes to @skb.
 *
 * Returns 0 if successful, -EMSGSIZE if @skb has insufficient room, or another
 * negative error code if a real error occurred.  If an error occurs, @skb is
 * left unmodified.
 *
 * Must be called with ovs_mutex or rcu_read_lock.
 */
int ovs_vport_get_options(const struct vport *vport, struct sk_buff *skb)
{
        struct nlattr *nla;
        int err;

        if (!vport->ops->get_options)
                return 0;

        nla = nla_nest_start(skb, OVS_VPORT_ATTR_OPTIONS);
        if (!nla)
                return -EMSGSIZE;

        err = vport->ops->get_options(vport, skb);
        if (err) {
                nla_nest_cancel(skb, nla);
                return err;
        }

        nla_nest_end(skb, nla);
        return 0;
}

static void vport_portids_destroy_rcu_cb(struct rcu_head *rcu)
{
        struct vport_portids *ids = container_of(rcu, struct vport_portids,
                                                 rcu);

        kfree(ids);
}

/**
 *      ovs_vport_set_upcall_portids - set upcall portids of @vport.
 *
 * @vport: vport to modify.
 * @ids: new configuration, an array of port ids.
 *
 * Sets the vport's upcall_portids to @ids.
 *
 * Returns 0 if successful, -EINVAL if @ids is zero length or cannot be parsed
 * as an array of U32.
 *
 * Must be called with ovs_mutex.
 */
int ovs_vport_set_upcall_portids(struct vport *vport, const struct nlattr *ids)
{
        struct vport_portids *old, *vport_portids;

        if (!nla_len(ids) || nla_len(ids) % sizeof(u32))
                return -EINVAL;

        old = ovsl_dereference(vport->upcall_portids);

        vport_portids = kmalloc(sizeof *vport_portids + nla_len(ids),
                                GFP_KERNEL);
        if (!vport_portids)
                return -ENOMEM;

        vport_portids->n_ids = nla_len(ids) / sizeof(u32);
        vport_portids->rn_ids = reciprocal_value(vport_portids->n_ids);
        nla_memcpy(vport_portids->ids, ids, nla_len(ids));

        rcu_assign_pointer(vport->upcall_portids, vport_portids);

        if (old)
                call_rcu(&old->rcu, vport_portids_destroy_rcu_cb);

        return 0;
}

/**
 *      ovs_vport_get_upcall_portids - get the upcall_portids of @vport.
 *
 * @vport: vport from which to retrieve the portids.
 * @skb: sk_buff where portids should be appended.
 *
 * Retrieves the configuration of the given vport, appending the
 * %OVS_VPORT_ATTR_UPCALL_PID attribute which is the array of upcall
 * portids to @skb.
 *
 * Returns 0 if successful, -EMSGSIZE if @skb has insufficient room.
 * If an error occurs, @skb is left unmodified.  Must be called with
 * ovs_mutex or rcu_read_lock.
 */
int ovs_vport_get_upcall_portids(const struct vport *vport,
                                 struct sk_buff *skb)
{
        struct vport_portids *ids;

        ids = rcu_dereference_ovsl(vport->upcall_portids);

        if (vport->dp->user_features & OVS_DP_F_VPORT_PIDS)
                return nla_put(skb, OVS_VPORT_ATTR_UPCALL_PID,
                               ids->n_ids * sizeof(u32), (void *) ids->ids);
        else
                return nla_put_u32(skb, OVS_VPORT_ATTR_UPCALL_PID, ids->ids[0]);
}

/**
 *      ovs_vport_find_upcall_portid - find the upcall portid to send upcall.
 *
 * @vport: vport from which the missed packet is received.
 * @skb: skb that the missed packet was received.
 *
 * Uses the skb_get_hash() to select the upcall portid to send the
 * upcall.
 *
 * Returns the portid of the target socket.  Must be called with rcu_read_lock.
 */
u32 ovs_vport_find_upcall_portid(const struct vport *p, struct sk_buff *skb)
{
        struct vport_portids *ids;
        u32 hash;

        ids = rcu_dereference(p->upcall_portids);

        if (ids->n_ids == 1 && ids->ids[0] == 0)
                return 0;

        hash = skb_get_hash(skb);
        return ids->ids[hash - ids->n_ids * reciprocal_divide(hash, ids->rn_ids)];
}

/**
 *      ovs_vport_receive - pass up received packet to the datapath for processing
 *
 * @vport: vport that received the packet
 * @skb: skb that was received
 * @tun_info: tunnel (if any) that carried packet
 *
 * Must be called with rcu_read_lock.  The packet cannot be shared and
 * skb->data should point to the Ethernet header.  The caller must have already
 * called compute_ip_summed() to initialize the checksumming fields.
 */
void ovs_vport_receive(struct vport *vport, struct sk_buff *skb,
                       const struct ovs_tunnel_info *tun_info)
{
        struct pcpu_sw_netstats *stats;
        struct sw_flow_key key;
        int error;

        stats = this_cpu_ptr(vport->percpu_stats);
        u64_stats_update_begin(&stats->syncp);
        stats->rx_packets++;
        stats->rx_bytes += skb->len;
        u64_stats_update_end(&stats->syncp);

        ovs_skb_init_inner_protocol(skb);
        OVS_CB(skb)->input_vport = vport;
        OVS_CB(skb)->egress_tun_info = NULL;
        error = ovs_flow_key_extract(tun_info, skb, &key);
        if (unlikely(error)) {
                kfree_skb(skb);
                return;
        }

        ovs_dp_process_packet(skb, &key);
}

/**
 *      ovs_vport_send - send a packet on a device
 *
 * @vport: vport on which to send the packet
 * @skb: skb to send
 *
 * Sends the given packet and returns the length of data sent.  Either ovs
 * lock or rcu_read_lock must be held.
 */
int ovs_vport_send(struct vport *vport, struct sk_buff *skb)
{
        int sent = vport->ops->send(vport, skb);

        if (likely(sent > 0)) {
                struct pcpu_sw_netstats *stats;

                stats = this_cpu_ptr(vport->percpu_stats);

                u64_stats_update_begin(&stats->syncp);
                stats->tx_packets++;
                stats->tx_bytes += sent;
                u64_stats_update_end(&stats->syncp);
        } else if (sent < 0) {
                ovs_vport_record_error(vport, VPORT_E_TX_ERROR);
                kfree_skb(skb);
        } else
                ovs_vport_record_error(vport, VPORT_E_TX_DROPPED);

        return sent;
}

/**
 *      ovs_vport_record_error - indicate device error to generic stats layer
 *
 * @vport: vport that encountered the error
 * @err_type: one of enum vport_err_type types to indicate the error type
 *
 * If using the vport generic stats layer indicate that an error of the given
 * type has occurred.
 */
static void ovs_vport_record_error(struct vport *vport,
                                   enum vport_err_type err_type)
{
        switch (err_type) {
        case VPORT_E_RX_DROPPED:
                atomic_long_inc(&vport->err_stats.rx_dropped);
                break;

        case VPORT_E_RX_ERROR:
                atomic_long_inc(&vport->err_stats.rx_errors);
                break;

        case VPORT_E_TX_DROPPED:
                atomic_long_inc(&vport->err_stats.tx_dropped);
                break;

        case VPORT_E_TX_ERROR:
                atomic_long_inc(&vport->err_stats.tx_errors);
                break;
        }
}

static void free_vport_rcu(struct rcu_head *rcu)
{
        struct vport *vport = container_of(rcu, struct vport, rcu);

        ovs_vport_free(vport);
}

void ovs_vport_deferred_free(struct vport *vport)
{
        if (!vport)
                return;

        call_rcu(&vport->rcu, free_vport_rcu);
}

int ovs_tunnel_get_egress_info(struct ovs_tunnel_info *egress_tun_info,
                               struct net *net,
                               const struct ovs_tunnel_info *tun_info,
                               u8 ipproto,
                               u32 skb_mark,
                               __be16 tp_src,
                               __be16 tp_dst)
{
        const struct ovs_key_ipv4_tunnel *tun_key;
        struct rtable *rt;
        __be32 saddr;

        if (unlikely(!tun_info))
                return -EINVAL;

        tun_key = &tun_info->tunnel;
        saddr = tun_key->ipv4_src;
        /* Route lookup to get srouce IP address: saddr.
         * The process may need to be changed if the corresponding process
         * in vports ops changed.
         */
        rt = find_route(net,
                        &saddr,
                        tun_key->ipv4_dst,
                        ipproto,
                        tun_key->ipv4_tos,
                        skb_mark);
        if (IS_ERR(rt))
                return PTR_ERR(rt);

        ip_rt_put(rt);

        /* Generate egress_tun_info based on tun_info,
         * saddr, tp_src and tp_dst
         */
        __ovs_flow_tun_info_init(egress_tun_info,
                                 saddr, tun_key->ipv4_dst,
                                 tun_key->ipv4_tos,
                                 tun_key->ipv4_ttl,
                                 tp_src, tp_dst,
                                 tun_key->tun_id,
                                 tun_key->tun_flags,
                                 tun_info->options,
                                 tun_info->options_len);

        return 0;
}

int ovs_vport_get_egress_tun_info(struct vport *vport, struct sk_buff *skb,
                                  struct ovs_tunnel_info *info)
{
        /* get_egress_tun_info() is only implemented on tunnel ports. */
        if (unlikely(!vport->ops->get_egress_tun_info))
                return -EINVAL;

        return vport->ops->get_egress_tun_info(vport, skb, info);
}