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datapath.c
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datapath.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2007-2014 Nicira, Inc.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/jhash.h>
#include <linux/delay.h>
#include <linux/time.h>
#include <linux/etherdevice.h>
#include <linux/genetlink.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/ethtool.h>
#include <linux/wait.h>
#include <asm/div64.h>
#include <linux/highmem.h>
#include <linux/netfilter_bridge.h>
#include <linux/netfilter_ipv4.h>
#include <linux/inetdevice.h>
#include <linux/list.h>
#include <linux/openvswitch.h>
#include <linux/rculist.h>
#include <linux/dmi.h>
#include <net/genetlink.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include "datapath.h"
#include "flow.h"
#include "flow_table.h"
#include "flow_netlink.h"
#include "meter.h"
#include "vport-internal_dev.h"
#include "vport-netdev.h"
unsigned int ovs_net_id __read_mostly;
static struct genl_family dp_packet_genl_family;
static struct genl_family dp_flow_genl_family;
static struct genl_family dp_datapath_genl_family;
static const struct nla_policy flow_policy[];
static const struct genl_multicast_group ovs_dp_flow_multicast_group = {
.name = OVS_FLOW_MCGROUP,
};
static const struct genl_multicast_group ovs_dp_datapath_multicast_group = {
.name = OVS_DATAPATH_MCGROUP,
};
static const struct genl_multicast_group ovs_dp_vport_multicast_group = {
.name = OVS_VPORT_MCGROUP,
};
/* Check if need to build a reply message.
* OVS userspace sets the NLM_F_ECHO flag if it needs the reply. */
static bool ovs_must_notify(struct genl_family *family, struct genl_info *info,
unsigned int group)
{
return info->nlhdr->nlmsg_flags & NLM_F_ECHO ||
genl_has_listeners(family, genl_info_net(info), group);
}
static void ovs_notify(struct genl_family *family,
struct sk_buff *skb, struct genl_info *info)
{
genl_notify(family, skb, info, 0, GFP_KERNEL);
}
/**
* DOC: Locking:
*
* All writes e.g. Writes to device state (add/remove datapath, port, set
* operations on vports, etc.), Writes to other state (flow table
* modifications, set miscellaneous datapath parameters, etc.) are protected
* by ovs_lock.
*
* Reads are protected by RCU.
*
* There are a few special cases (mostly stats) that have their own
* synchronization but they nest under all of above and don't interact with
* each other.
*
* The RTNL lock nests inside ovs_mutex.
*/
static DEFINE_MUTEX(ovs_mutex);
void ovs_lock(void)
{
mutex_lock(&ovs_mutex);
}
void ovs_unlock(void)
{
mutex_unlock(&ovs_mutex);
}
#ifdef CONFIG_LOCKDEP
int lockdep_ovsl_is_held(void)
{
if (debug_locks)
return lockdep_is_held(&ovs_mutex);
else
return 1;
}
#endif
static struct vport *new_vport(const struct vport_parms *);
static int queue_gso_packets(struct datapath *dp, struct sk_buff *,
const struct sw_flow_key *,
const struct dp_upcall_info *,
uint32_t cutlen);
static int queue_userspace_packet(struct datapath *dp, struct sk_buff *,
const struct sw_flow_key *,
const struct dp_upcall_info *,
uint32_t cutlen);
/* Must be called with rcu_read_lock or ovs_mutex. */
const char *ovs_dp_name(const struct datapath *dp)
{
struct vport *vport = ovs_vport_ovsl_rcu(dp, OVSP_LOCAL);
return ovs_vport_name(vport);
}
static int get_dpifindex(const struct datapath *dp)
{
struct vport *local;
int ifindex;
rcu_read_lock();
local = ovs_vport_rcu(dp, OVSP_LOCAL);
if (local)
ifindex = local->dev->ifindex;
else
ifindex = 0;
rcu_read_unlock();
return ifindex;
}
static void destroy_dp_rcu(struct rcu_head *rcu)
{
struct datapath *dp = container_of(rcu, struct datapath, rcu);
ovs_flow_tbl_destroy(&dp->table);
free_percpu(dp->stats_percpu);
kfree(dp->ports);
ovs_meters_exit(dp);
kfree(dp);
}
static struct hlist_head *vport_hash_bucket(const struct datapath *dp,
u16 port_no)
{
return &dp->ports[port_no & (DP_VPORT_HASH_BUCKETS - 1)];
}
/* Called with ovs_mutex or RCU read lock. */
struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no)
{
struct vport *vport;
struct hlist_head *head;
head = vport_hash_bucket(dp, port_no);
hlist_for_each_entry_rcu(vport, head, dp_hash_node,
lockdep_ovsl_is_held()) {
if (vport->port_no == port_no)
return vport;
}
return NULL;
}
/* Called with ovs_mutex. */
static struct vport *new_vport(const struct vport_parms *parms)
{
struct vport *vport;
vport = ovs_vport_add(parms);
if (!IS_ERR(vport)) {
struct datapath *dp = parms->dp;
struct hlist_head *head = vport_hash_bucket(dp, vport->port_no);
hlist_add_head_rcu(&vport->dp_hash_node, head);
}
return vport;
}
void ovs_dp_detach_port(struct vport *p)
{
ASSERT_OVSL();
/* First drop references to device. */
hlist_del_rcu(&p->dp_hash_node);
/* Then destroy it. */
ovs_vport_del(p);
}
/* Must be called with rcu_read_lock. */
void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key)
{
const struct vport *p = OVS_CB(skb)->input_vport;
struct datapath *dp = p->dp;
struct sw_flow *flow;
struct sw_flow_actions *sf_acts;
struct dp_stats_percpu *stats;
u64 *stats_counter;
u32 n_mask_hit;
int error;
stats = this_cpu_ptr(dp->stats_percpu);
/* Look up flow. */
flow = ovs_flow_tbl_lookup_stats(&dp->table, key, skb_get_hash(skb),
&n_mask_hit);
if (unlikely(!flow)) {
struct dp_upcall_info upcall;
memset(&upcall, 0, sizeof(upcall));
upcall.cmd = OVS_PACKET_CMD_MISS;
upcall.portid = ovs_vport_find_upcall_portid(p, skb);
upcall.mru = OVS_CB(skb)->mru;
error = ovs_dp_upcall(dp, skb, key, &upcall, 0);
if (unlikely(error))
kfree_skb(skb);
else
consume_skb(skb);
stats_counter = &stats->n_missed;
goto out;
}
ovs_flow_stats_update(flow, key->tp.flags, skb);
sf_acts = rcu_dereference(flow->sf_acts);
error = ovs_execute_actions(dp, skb, sf_acts, key);
if (unlikely(error))
net_dbg_ratelimited("ovs: action execution error on datapath %s: %d\n",
ovs_dp_name(dp), error);
stats_counter = &stats->n_hit;
out:
/* Update datapath statistics. */
u64_stats_update_begin(&stats->syncp);
(*stats_counter)++;
stats->n_mask_hit += n_mask_hit;
u64_stats_update_end(&stats->syncp);
}
int ovs_dp_upcall(struct datapath *dp, struct sk_buff *skb,
const struct sw_flow_key *key,
const struct dp_upcall_info *upcall_info,
uint32_t cutlen)
{
struct dp_stats_percpu *stats;
int err;
if (upcall_info->portid == 0) {
err = -ENOTCONN;
goto err;
}
if (!skb_is_gso(skb))
err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen);
else
err = queue_gso_packets(dp, skb, key, upcall_info, cutlen);
if (err)
goto err;
return 0;
err:
stats = this_cpu_ptr(dp->stats_percpu);
u64_stats_update_begin(&stats->syncp);
stats->n_lost++;
u64_stats_update_end(&stats->syncp);
return err;
}
static int queue_gso_packets(struct datapath *dp, struct sk_buff *skb,
const struct sw_flow_key *key,
const struct dp_upcall_info *upcall_info,
uint32_t cutlen)
{
unsigned int gso_type = skb_shinfo(skb)->gso_type;
struct sw_flow_key later_key;
struct sk_buff *segs, *nskb;
int err;
BUILD_BUG_ON(sizeof(*OVS_CB(skb)) > SKB_GSO_CB_OFFSET);
segs = __skb_gso_segment(skb, NETIF_F_SG, false);
if (IS_ERR(segs))
return PTR_ERR(segs);
if (segs == NULL)
return -EINVAL;
if (gso_type & SKB_GSO_UDP) {
/* The initial flow key extracted by ovs_flow_key_extract()
* in this case is for a first fragment, so we need to
* properly mark later fragments.
*/
later_key = *key;
later_key.ip.frag = OVS_FRAG_TYPE_LATER;
}
/* Queue all of the segments. */
skb_list_walk_safe(segs, skb, nskb) {
if (gso_type & SKB_GSO_UDP && skb != segs)
key = &later_key;
err = queue_userspace_packet(dp, skb, key, upcall_info, cutlen);
if (err)
break;
}
/* Free all of the segments. */
skb_list_walk_safe(segs, skb, nskb) {
if (err)
kfree_skb(skb);
else
consume_skb(skb);
}
return err;
}
static size_t upcall_msg_size(const struct dp_upcall_info *upcall_info,
unsigned int hdrlen, int actions_attrlen)
{
size_t size = NLMSG_ALIGN(sizeof(struct ovs_header))
+ nla_total_size(hdrlen) /* OVS_PACKET_ATTR_PACKET */
+ nla_total_size(ovs_key_attr_size()) /* OVS_PACKET_ATTR_KEY */
+ nla_total_size(sizeof(unsigned int)) /* OVS_PACKET_ATTR_LEN */
+ nla_total_size(sizeof(u64)); /* OVS_PACKET_ATTR_HASH */
/* OVS_PACKET_ATTR_USERDATA */
if (upcall_info->userdata)
size += NLA_ALIGN(upcall_info->userdata->nla_len);
/* OVS_PACKET_ATTR_EGRESS_TUN_KEY */
if (upcall_info->egress_tun_info)
size += nla_total_size(ovs_tun_key_attr_size());
/* OVS_PACKET_ATTR_ACTIONS */
if (upcall_info->actions_len)
size += nla_total_size(actions_attrlen);
/* OVS_PACKET_ATTR_MRU */
if (upcall_info->mru)
size += nla_total_size(sizeof(upcall_info->mru));
return size;
}
static void pad_packet(struct datapath *dp, struct sk_buff *skb)
{
if (!(dp->user_features & OVS_DP_F_UNALIGNED)) {
size_t plen = NLA_ALIGN(skb->len) - skb->len;
if (plen > 0)
skb_put_zero(skb, plen);
}
}
static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb,
const struct sw_flow_key *key,
const struct dp_upcall_info *upcall_info,
uint32_t cutlen)
{
struct ovs_header *upcall;
struct sk_buff *nskb = NULL;
struct sk_buff *user_skb = NULL; /* to be queued to userspace */
struct nlattr *nla;
size_t len;
unsigned int hlen;
int err, dp_ifindex;
u64 hash;
dp_ifindex = get_dpifindex(dp);
if (!dp_ifindex)
return -ENODEV;
if (skb_vlan_tag_present(skb)) {
nskb = skb_clone(skb, GFP_ATOMIC);
if (!nskb)
return -ENOMEM;
nskb = __vlan_hwaccel_push_inside(nskb);
if (!nskb)
return -ENOMEM;
skb = nskb;
}
if (nla_attr_size(skb->len) > USHRT_MAX) {
err = -EFBIG;
goto out;
}
/* Complete checksum if needed */
if (skb->ip_summed == CHECKSUM_PARTIAL &&
(err = skb_csum_hwoffload_help(skb, 0)))
goto out;
/* Older versions of OVS user space enforce alignment of the last
* Netlink attribute to NLA_ALIGNTO which would require extensive
* padding logic. Only perform zerocopy if padding is not required.
*/
if (dp->user_features & OVS_DP_F_UNALIGNED)
hlen = skb_zerocopy_headlen(skb);
else
hlen = skb->len;
len = upcall_msg_size(upcall_info, hlen - cutlen,
OVS_CB(skb)->acts_origlen);
user_skb = genlmsg_new(len, GFP_ATOMIC);
if (!user_skb) {
err = -ENOMEM;
goto out;
}
upcall = genlmsg_put(user_skb, 0, 0, &dp_packet_genl_family,
0, upcall_info->cmd);
if (!upcall) {
err = -EINVAL;
goto out;
}
upcall->dp_ifindex = dp_ifindex;
err = ovs_nla_put_key(key, key, OVS_PACKET_ATTR_KEY, false, user_skb);
if (err)
goto out;
if (upcall_info->userdata)
__nla_put(user_skb, OVS_PACKET_ATTR_USERDATA,
nla_len(upcall_info->userdata),
nla_data(upcall_info->userdata));
if (upcall_info->egress_tun_info) {
nla = nla_nest_start_noflag(user_skb,
OVS_PACKET_ATTR_EGRESS_TUN_KEY);
if (!nla) {
err = -EMSGSIZE;
goto out;
}
err = ovs_nla_put_tunnel_info(user_skb,
upcall_info->egress_tun_info);
if (err)
goto out;
nla_nest_end(user_skb, nla);
}
if (upcall_info->actions_len) {
nla = nla_nest_start_noflag(user_skb, OVS_PACKET_ATTR_ACTIONS);
if (!nla) {
err = -EMSGSIZE;
goto out;
}
err = ovs_nla_put_actions(upcall_info->actions,
upcall_info->actions_len,
user_skb);
if (!err)
nla_nest_end(user_skb, nla);
else
nla_nest_cancel(user_skb, nla);
}
/* Add OVS_PACKET_ATTR_MRU */
if (upcall_info->mru &&
nla_put_u16(user_skb, OVS_PACKET_ATTR_MRU, upcall_info->mru)) {
err = -ENOBUFS;
goto out;
}
/* Add OVS_PACKET_ATTR_LEN when packet is truncated */
if (cutlen > 0 &&
nla_put_u32(user_skb, OVS_PACKET_ATTR_LEN, skb->len)) {
err = -ENOBUFS;
goto out;
}
/* Add OVS_PACKET_ATTR_HASH */
hash = skb_get_hash_raw(skb);
if (skb->sw_hash)
hash |= OVS_PACKET_HASH_SW_BIT;
if (skb->l4_hash)
hash |= OVS_PACKET_HASH_L4_BIT;
if (nla_put(user_skb, OVS_PACKET_ATTR_HASH, sizeof (u64), &hash)) {
err = -ENOBUFS;
goto out;
}
/* Only reserve room for attribute header, packet data is added
* in skb_zerocopy() */
if (!(nla = nla_reserve(user_skb, OVS_PACKET_ATTR_PACKET, 0))) {
err = -ENOBUFS;
goto out;
}
nla->nla_len = nla_attr_size(skb->len - cutlen);
err = skb_zerocopy(user_skb, skb, skb->len - cutlen, hlen);
if (err)
goto out;
/* Pad OVS_PACKET_ATTR_PACKET if linear copy was performed */
pad_packet(dp, user_skb);
((struct nlmsghdr *) user_skb->data)->nlmsg_len = user_skb->len;
err = genlmsg_unicast(ovs_dp_get_net(dp), user_skb, upcall_info->portid);
user_skb = NULL;
out:
if (err)
skb_tx_error(skb);
kfree_skb(user_skb);
kfree_skb(nskb);
return err;
}
static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
{
struct ovs_header *ovs_header = info->userhdr;
struct net *net = sock_net(skb->sk);
struct nlattr **a = info->attrs;
struct sw_flow_actions *acts;
struct sk_buff *packet;
struct sw_flow *flow;
struct sw_flow_actions *sf_acts;
struct datapath *dp;
struct vport *input_vport;
u16 mru = 0;
u64 hash;
int len;
int err;
bool log = !a[OVS_PACKET_ATTR_PROBE];
err = -EINVAL;
if (!a[OVS_PACKET_ATTR_PACKET] || !a[OVS_PACKET_ATTR_KEY] ||
!a[OVS_PACKET_ATTR_ACTIONS])
goto err;
len = nla_len(a[OVS_PACKET_ATTR_PACKET]);
packet = __dev_alloc_skb(NET_IP_ALIGN + len, GFP_KERNEL);
err = -ENOMEM;
if (!packet)
goto err;
skb_reserve(packet, NET_IP_ALIGN);
nla_memcpy(__skb_put(packet, len), a[OVS_PACKET_ATTR_PACKET], len);
/* Set packet's mru */
if (a[OVS_PACKET_ATTR_MRU]) {
mru = nla_get_u16(a[OVS_PACKET_ATTR_MRU]);
packet->ignore_df = 1;
}
OVS_CB(packet)->mru = mru;
if (a[OVS_PACKET_ATTR_HASH]) {
hash = nla_get_u64(a[OVS_PACKET_ATTR_HASH]);
__skb_set_hash(packet, hash & 0xFFFFFFFFULL,
!!(hash & OVS_PACKET_HASH_SW_BIT),
!!(hash & OVS_PACKET_HASH_L4_BIT));
}
/* Build an sw_flow for sending this packet. */
flow = ovs_flow_alloc();
err = PTR_ERR(flow);
if (IS_ERR(flow))
goto err_kfree_skb;
err = ovs_flow_key_extract_userspace(net, a[OVS_PACKET_ATTR_KEY],
packet, &flow->key, log);
if (err)
goto err_flow_free;
err = ovs_nla_copy_actions(net, a[OVS_PACKET_ATTR_ACTIONS],
&flow->key, &acts, log);
if (err)
goto err_flow_free;
rcu_assign_pointer(flow->sf_acts, acts);
packet->priority = flow->key.phy.priority;
packet->mark = flow->key.phy.skb_mark;
rcu_read_lock();
dp = get_dp_rcu(net, ovs_header->dp_ifindex);
err = -ENODEV;
if (!dp)
goto err_unlock;
input_vport = ovs_vport_rcu(dp, flow->key.phy.in_port);
if (!input_vport)
input_vport = ovs_vport_rcu(dp, OVSP_LOCAL);
if (!input_vport)
goto err_unlock;
packet->dev = input_vport->dev;
OVS_CB(packet)->input_vport = input_vport;
sf_acts = rcu_dereference(flow->sf_acts);
local_bh_disable();
err = ovs_execute_actions(dp, packet, sf_acts, &flow->key);
local_bh_enable();
rcu_read_unlock();
ovs_flow_free(flow, false);
return err;
err_unlock:
rcu_read_unlock();
err_flow_free:
ovs_flow_free(flow, false);
err_kfree_skb:
kfree_skb(packet);
err:
return err;
}
static const struct nla_policy packet_policy[OVS_PACKET_ATTR_MAX + 1] = {
[OVS_PACKET_ATTR_PACKET] = { .len = ETH_HLEN },
[OVS_PACKET_ATTR_KEY] = { .type = NLA_NESTED },
[OVS_PACKET_ATTR_ACTIONS] = { .type = NLA_NESTED },
[OVS_PACKET_ATTR_PROBE] = { .type = NLA_FLAG },
[OVS_PACKET_ATTR_MRU] = { .type = NLA_U16 },
[OVS_PACKET_ATTR_HASH] = { .type = NLA_U64 },
};
static const struct genl_ops dp_packet_genl_ops[] = {
{ .cmd = OVS_PACKET_CMD_EXECUTE,
.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
.flags = GENL_UNS_ADMIN_PERM, /* Requires CAP_NET_ADMIN privilege. */
.doit = ovs_packet_cmd_execute
}
};
static struct genl_family dp_packet_genl_family __ro_after_init = {
.hdrsize = sizeof(struct ovs_header),
.name = OVS_PACKET_FAMILY,
.version = OVS_PACKET_VERSION,
.maxattr = OVS_PACKET_ATTR_MAX,
.policy = packet_policy,
.netnsok = true,
.parallel_ops = true,
.ops = dp_packet_genl_ops,
.n_ops = ARRAY_SIZE(dp_packet_genl_ops),
.module = THIS_MODULE,
};
static void get_dp_stats(const struct datapath *dp, struct ovs_dp_stats *stats,
struct ovs_dp_megaflow_stats *mega_stats)
{
int i;
memset(mega_stats, 0, sizeof(*mega_stats));
stats->n_flows = ovs_flow_tbl_count(&dp->table);
mega_stats->n_masks = ovs_flow_tbl_num_masks(&dp->table);
stats->n_hit = stats->n_missed = stats->n_lost = 0;
for_each_possible_cpu(i) {
const struct dp_stats_percpu *percpu_stats;
struct dp_stats_percpu local_stats;
unsigned int start;
percpu_stats = per_cpu_ptr(dp->stats_percpu, 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->n_hit += local_stats.n_hit;
stats->n_missed += local_stats.n_missed;
stats->n_lost += local_stats.n_lost;
mega_stats->n_mask_hit += local_stats.n_mask_hit;
}
}
static bool should_fill_key(const struct sw_flow_id *sfid, uint32_t ufid_flags)
{
return ovs_identifier_is_ufid(sfid) &&
!(ufid_flags & OVS_UFID_F_OMIT_KEY);
}
static bool should_fill_mask(uint32_t ufid_flags)
{
return !(ufid_flags & OVS_UFID_F_OMIT_MASK);
}
static bool should_fill_actions(uint32_t ufid_flags)
{
return !(ufid_flags & OVS_UFID_F_OMIT_ACTIONS);
}
static size_t ovs_flow_cmd_msg_size(const struct sw_flow_actions *acts,
const struct sw_flow_id *sfid,
uint32_t ufid_flags)
{
size_t len = NLMSG_ALIGN(sizeof(struct ovs_header));
/* OVS_FLOW_ATTR_UFID, or unmasked flow key as fallback
* see ovs_nla_put_identifier()
*/
if (sfid && ovs_identifier_is_ufid(sfid))
len += nla_total_size(sfid->ufid_len);
else
len += nla_total_size(ovs_key_attr_size());
/* OVS_FLOW_ATTR_KEY */
if (!sfid || should_fill_key(sfid, ufid_flags))
len += nla_total_size(ovs_key_attr_size());
/* OVS_FLOW_ATTR_MASK */
if (should_fill_mask(ufid_flags))
len += nla_total_size(ovs_key_attr_size());
/* OVS_FLOW_ATTR_ACTIONS */
if (should_fill_actions(ufid_flags))
len += nla_total_size(acts->orig_len);
return len
+ nla_total_size_64bit(sizeof(struct ovs_flow_stats)) /* OVS_FLOW_ATTR_STATS */
+ nla_total_size(1) /* OVS_FLOW_ATTR_TCP_FLAGS */
+ nla_total_size_64bit(8); /* OVS_FLOW_ATTR_USED */
}
/* Called with ovs_mutex or RCU read lock. */
static int ovs_flow_cmd_fill_stats(const struct sw_flow *flow,
struct sk_buff *skb)
{
struct ovs_flow_stats stats;
__be16 tcp_flags;
unsigned long used;
ovs_flow_stats_get(flow, &stats, &used, &tcp_flags);
if (used &&
nla_put_u64_64bit(skb, OVS_FLOW_ATTR_USED, ovs_flow_used_time(used),
OVS_FLOW_ATTR_PAD))
return -EMSGSIZE;
if (stats.n_packets &&
nla_put_64bit(skb, OVS_FLOW_ATTR_STATS,
sizeof(struct ovs_flow_stats), &stats,
OVS_FLOW_ATTR_PAD))
return -EMSGSIZE;
if ((u8)ntohs(tcp_flags) &&
nla_put_u8(skb, OVS_FLOW_ATTR_TCP_FLAGS, (u8)ntohs(tcp_flags)))
return -EMSGSIZE;
return 0;
}
/* Called with ovs_mutex or RCU read lock. */
static int ovs_flow_cmd_fill_actions(const struct sw_flow *flow,
struct sk_buff *skb, int skb_orig_len)
{
struct nlattr *start;
int err;
/* If OVS_FLOW_ATTR_ACTIONS doesn't fit, skip dumping the actions if
* this is the first flow to be dumped into 'skb'. This is unusual for
* Netlink but individual action lists can be longer than
* NLMSG_GOODSIZE and thus entirely undumpable if we didn't do this.
* The userspace caller can always fetch the actions separately if it
* really wants them. (Most userspace callers in fact don't care.)
*
* This can only fail for dump operations because the skb is always
* properly sized for single flows.
*/
start = nla_nest_start_noflag(skb, OVS_FLOW_ATTR_ACTIONS);
if (start) {
const struct sw_flow_actions *sf_acts;
sf_acts = rcu_dereference_ovsl(flow->sf_acts);
err = ovs_nla_put_actions(sf_acts->actions,
sf_acts->actions_len, skb);
if (!err)
nla_nest_end(skb, start);
else {
if (skb_orig_len)
return err;
nla_nest_cancel(skb, start);
}
} else if (skb_orig_len) {
return -EMSGSIZE;
}
return 0;
}
/* Called with ovs_mutex or RCU read lock. */
static int ovs_flow_cmd_fill_info(const struct sw_flow *flow, int dp_ifindex,
struct sk_buff *skb, u32 portid,
u32 seq, u32 flags, u8 cmd, u32 ufid_flags)
{
const int skb_orig_len = skb->len;
struct ovs_header *ovs_header;
int err;
ovs_header = genlmsg_put(skb, portid, seq, &dp_flow_genl_family,
flags, cmd);
if (!ovs_header)
return -EMSGSIZE;
ovs_header->dp_ifindex = dp_ifindex;
err = ovs_nla_put_identifier(flow, skb);
if (err)
goto error;
if (should_fill_key(&flow->id, ufid_flags)) {
err = ovs_nla_put_masked_key(flow, skb);
if (err)
goto error;
}
if (should_fill_mask(ufid_flags)) {
err = ovs_nla_put_mask(flow, skb);
if (err)
goto error;
}
err = ovs_flow_cmd_fill_stats(flow, skb);
if (err)
goto error;
if (should_fill_actions(ufid_flags)) {
err = ovs_flow_cmd_fill_actions(flow, skb, skb_orig_len);
if (err)
goto error;
}
genlmsg_end(skb, ovs_header);
return 0;
error:
genlmsg_cancel(skb, ovs_header);
return err;
}
/* May not be called with RCU read lock. */
static struct sk_buff *ovs_flow_cmd_alloc_info(const struct sw_flow_actions *acts,
const struct sw_flow_id *sfid,
struct genl_info *info,
bool always,
uint32_t ufid_flags)
{
struct sk_buff *skb;
size_t len;
if (!always && !ovs_must_notify(&dp_flow_genl_family, info, 0))
return NULL;
len = ovs_flow_cmd_msg_size(acts, sfid, ufid_flags);
skb = genlmsg_new(len, GFP_KERNEL);
if (!skb)
return ERR_PTR(-ENOMEM);
return skb;
}
/* Called with ovs_mutex. */
static struct sk_buff *ovs_flow_cmd_build_info(const struct sw_flow *flow,
int dp_ifindex,
struct genl_info *info, u8 cmd,
bool always, u32 ufid_flags)
{
struct sk_buff *skb;
int retval;
skb = ovs_flow_cmd_alloc_info(ovsl_dereference(flow->sf_acts),
&flow->id, info, always, ufid_flags);
if (IS_ERR_OR_NULL(skb))
return skb;
retval = ovs_flow_cmd_fill_info(flow, dp_ifindex, skb,
info->snd_portid, info->snd_seq, 0,
cmd, ufid_flags);
if (WARN_ON_ONCE(retval < 0)) {
kfree_skb(skb);
skb = ERR_PTR(retval);
}
return skb;
}
static int ovs_flow_cmd_new(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = sock_net(skb->sk);
struct nlattr **a = info->attrs;
struct ovs_header *ovs_header = info->userhdr;
struct sw_flow *flow = NULL, *new_flow;
struct sw_flow_mask mask;
struct sk_buff *reply;
struct datapath *dp;
struct sw_flow_actions *acts;
struct sw_flow_match match;
u32 ufid_flags = ovs_nla_get_ufid_flags(a[OVS_FLOW_ATTR_UFID_FLAGS]);
int error;
bool log = !a[OVS_FLOW_ATTR_PROBE];
/* Must have key and actions. */
error = -EINVAL;
if (!a[OVS_FLOW_ATTR_KEY]) {
OVS_NLERR(log, "Flow key attr not present in new flow.");
goto error;
}
if (!a[OVS_FLOW_ATTR_ACTIONS]) {
OVS_NLERR(log, "Flow actions attr not present in new flow.");
goto error;
}
/* Most of the time we need to allocate a new flow, do it before
* locking.
*/
new_flow = ovs_flow_alloc();
if (IS_ERR(new_flow)) {
error = PTR_ERR(new_flow);
goto error;
}
/* Extract key. */
ovs_match_init(&match, &new_flow->key, false, &mask);
error = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
a[OVS_FLOW_ATTR_MASK], log);
if (error)
goto err_kfree_flow;
/* Extract flow identifier. */
error = ovs_nla_get_identifier(&new_flow->id, a[OVS_FLOW_ATTR_UFID],
&new_flow->key, log);
if (error)
goto err_kfree_flow;
/* unmasked key is needed to match when ufid is not used. */
if (ovs_identifier_is_key(&new_flow->id))
match.key = new_flow->id.unmasked_key;
ovs_flow_mask_key(&new_flow->key, &new_flow->key, true, &mask);
/* Validate actions. */
error = ovs_nla_copy_actions(net, a[OVS_FLOW_ATTR_ACTIONS],
&new_flow->key, &acts, log);
if (error) {
OVS_NLERR(log, "Flow actions may not be safe on all matching packets.");
goto err_kfree_flow;
}
reply = ovs_flow_cmd_alloc_info(acts, &new_flow->id, info, false,
ufid_flags);
if (IS_ERR(reply)) {
error = PTR_ERR(reply);
goto err_kfree_acts;
}
ovs_lock();
dp = get_dp(net, ovs_header->dp_ifindex);
if (unlikely(!dp)) {
error = -ENODEV;
goto err_unlock_ovs;
}
/* Check if this is a duplicate flow */
if (ovs_identifier_is_ufid(&new_flow->id))
flow = ovs_flow_tbl_lookup_ufid(&dp->table, &new_flow->id);
if (!flow)
flow = ovs_flow_tbl_lookup(&dp->table, &new_flow->key);
if (likely(!flow)) {
rcu_assign_pointer(new_flow->sf_acts, acts);
/* Put flow in bucket. */
error = ovs_flow_tbl_insert(&dp->table, new_flow, &mask);
if (unlikely(error)) {