diff options
Diffstat (limited to 'net/openvswitch/meter.c')
| -rw-r--r-- | net/openvswitch/meter.c | 768 |
1 files changed, 768 insertions, 0 deletions
diff --git a/net/openvswitch/meter.c b/net/openvswitch/meter.c new file mode 100644 index 000000000..0cf3dda53 --- /dev/null +++ b/net/openvswitch/meter.c @@ -0,0 +1,768 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2017 Nicira, Inc. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/if.h> +#include <linux/skbuff.h> +#include <linux/ip.h> +#include <linux/kernel.h> +#include <linux/openvswitch.h> +#include <linux/netlink.h> +#include <linux/rculist.h> +#include <linux/swap.h> + +#include <net/netlink.h> +#include <net/genetlink.h> + +#include "datapath.h" +#include "meter.h" + +static const struct nla_policy meter_policy[OVS_METER_ATTR_MAX + 1] = { + [OVS_METER_ATTR_ID] = { .type = NLA_U32, }, + [OVS_METER_ATTR_KBPS] = { .type = NLA_FLAG }, + [OVS_METER_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) }, + [OVS_METER_ATTR_BANDS] = { .type = NLA_NESTED }, + [OVS_METER_ATTR_USED] = { .type = NLA_U64 }, + [OVS_METER_ATTR_CLEAR] = { .type = NLA_FLAG }, + [OVS_METER_ATTR_MAX_METERS] = { .type = NLA_U32 }, + [OVS_METER_ATTR_MAX_BANDS] = { .type = NLA_U32 }, +}; + +static const struct nla_policy band_policy[OVS_BAND_ATTR_MAX + 1] = { + [OVS_BAND_ATTR_TYPE] = { .type = NLA_U32, }, + [OVS_BAND_ATTR_RATE] = { .type = NLA_U32, }, + [OVS_BAND_ATTR_BURST] = { .type = NLA_U32, }, + [OVS_BAND_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) }, +}; + +static u32 meter_hash(struct dp_meter_instance *ti, u32 id) +{ + return id % ti->n_meters; +} + +static void ovs_meter_free(struct dp_meter *meter) +{ + if (!meter) + return; + + kfree_rcu(meter, rcu); +} + +/* Call with ovs_mutex or RCU read lock. */ +static struct dp_meter *lookup_meter(const struct dp_meter_table *tbl, + u32 meter_id) +{ + struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti); + u32 hash = meter_hash(ti, meter_id); + struct dp_meter *meter; + + meter = rcu_dereference_ovsl(ti->dp_meters[hash]); + if (meter && likely(meter->id == meter_id)) + return meter; + + return NULL; +} + +static struct dp_meter_instance *dp_meter_instance_alloc(const u32 size) +{ + struct dp_meter_instance *ti; + + ti = kvzalloc(sizeof(*ti) + + sizeof(struct dp_meter *) * size, + GFP_KERNEL); + if (!ti) + return NULL; + + ti->n_meters = size; + + return ti; +} + +static void dp_meter_instance_free(struct dp_meter_instance *ti) +{ + kvfree(ti); +} + +static void dp_meter_instance_free_rcu(struct rcu_head *rcu) +{ + struct dp_meter_instance *ti; + + ti = container_of(rcu, struct dp_meter_instance, rcu); + kvfree(ti); +} + +static int +dp_meter_instance_realloc(struct dp_meter_table *tbl, u32 size) +{ + struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti); + int n_meters = min(size, ti->n_meters); + struct dp_meter_instance *new_ti; + int i; + + new_ti = dp_meter_instance_alloc(size); + if (!new_ti) + return -ENOMEM; + + for (i = 0; i < n_meters; i++) + if (rcu_dereference_ovsl(ti->dp_meters[i])) + new_ti->dp_meters[i] = ti->dp_meters[i]; + + rcu_assign_pointer(tbl->ti, new_ti); + call_rcu(&ti->rcu, dp_meter_instance_free_rcu); + + return 0; +} + +static void dp_meter_instance_insert(struct dp_meter_instance *ti, + struct dp_meter *meter) +{ + u32 hash; + + hash = meter_hash(ti, meter->id); + rcu_assign_pointer(ti->dp_meters[hash], meter); +} + +static void dp_meter_instance_remove(struct dp_meter_instance *ti, + struct dp_meter *meter) +{ + u32 hash; + + hash = meter_hash(ti, meter->id); + RCU_INIT_POINTER(ti->dp_meters[hash], NULL); +} + +static int attach_meter(struct dp_meter_table *tbl, struct dp_meter *meter) +{ + struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti); + u32 hash = meter_hash(ti, meter->id); + int err; + + /* In generally, slots selected should be empty, because + * OvS uses id-pool to fetch a available id. + */ + if (unlikely(rcu_dereference_ovsl(ti->dp_meters[hash]))) + return -EBUSY; + + dp_meter_instance_insert(ti, meter); + + /* That function is thread-safe. */ + tbl->count++; + if (tbl->count >= tbl->max_meters_allowed) { + err = -EFBIG; + goto attach_err; + } + + if (tbl->count >= ti->n_meters && + dp_meter_instance_realloc(tbl, ti->n_meters * 2)) { + err = -ENOMEM; + goto attach_err; + } + + return 0; + +attach_err: + dp_meter_instance_remove(ti, meter); + tbl->count--; + return err; +} + +static int detach_meter(struct dp_meter_table *tbl, struct dp_meter *meter) +{ + struct dp_meter_instance *ti; + + ASSERT_OVSL(); + if (!meter) + return 0; + + ti = rcu_dereference_ovsl(tbl->ti); + dp_meter_instance_remove(ti, meter); + + tbl->count--; + + /* Shrink the meter array if necessary. */ + if (ti->n_meters > DP_METER_ARRAY_SIZE_MIN && + tbl->count <= (ti->n_meters / 4)) { + int half_size = ti->n_meters / 2; + int i; + + /* Avoid hash collision, don't move slots to other place. + * Make sure there are no references of meters in array + * which will be released. + */ + for (i = half_size; i < ti->n_meters; i++) + if (rcu_dereference_ovsl(ti->dp_meters[i])) + goto out; + + if (dp_meter_instance_realloc(tbl, half_size)) + goto shrink_err; + } + +out: + return 0; + +shrink_err: + dp_meter_instance_insert(ti, meter); + tbl->count++; + return -ENOMEM; +} + +static struct sk_buff * +ovs_meter_cmd_reply_start(struct genl_info *info, u8 cmd, + struct ovs_header **ovs_reply_header) +{ + struct sk_buff *skb; + struct ovs_header *ovs_header = info->userhdr; + + skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); + if (!skb) + return ERR_PTR(-ENOMEM); + + *ovs_reply_header = genlmsg_put(skb, info->snd_portid, + info->snd_seq, + &dp_meter_genl_family, 0, cmd); + if (!*ovs_reply_header) { + nlmsg_free(skb); + return ERR_PTR(-EMSGSIZE); + } + (*ovs_reply_header)->dp_ifindex = ovs_header->dp_ifindex; + + return skb; +} + +static int ovs_meter_cmd_reply_stats(struct sk_buff *reply, u32 meter_id, + struct dp_meter *meter) +{ + struct nlattr *nla; + struct dp_meter_band *band; + u16 i; + + if (nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id)) + goto error; + + if (nla_put(reply, OVS_METER_ATTR_STATS, + sizeof(struct ovs_flow_stats), &meter->stats)) + goto error; + + if (nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used, + OVS_METER_ATTR_PAD)) + goto error; + + nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS); + if (!nla) + goto error; + + band = meter->bands; + + for (i = 0; i < meter->n_bands; ++i, ++band) { + struct nlattr *band_nla; + + band_nla = nla_nest_start_noflag(reply, OVS_BAND_ATTR_UNSPEC); + if (!band_nla || nla_put(reply, OVS_BAND_ATTR_STATS, + sizeof(struct ovs_flow_stats), + &band->stats)) + goto error; + nla_nest_end(reply, band_nla); + } + nla_nest_end(reply, nla); + + return 0; +error: + return -EMSGSIZE; +} + +static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info) +{ + struct ovs_header *ovs_header = info->userhdr; + struct ovs_header *ovs_reply_header; + struct nlattr *nla, *band_nla; + struct sk_buff *reply; + struct datapath *dp; + int err = -EMSGSIZE; + + reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_FEATURES, + &ovs_reply_header); + if (IS_ERR(reply)) + return PTR_ERR(reply); + + ovs_lock(); + dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex); + if (!dp) { + err = -ENODEV; + goto exit_unlock; + } + + if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS, + dp->meter_tbl.max_meters_allowed)) + goto exit_unlock; + + ovs_unlock(); + + if (nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS)) + goto nla_put_failure; + + nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS); + if (!nla) + goto nla_put_failure; + + band_nla = nla_nest_start_noflag(reply, OVS_BAND_ATTR_UNSPEC); + if (!band_nla) + goto nla_put_failure; + /* Currently only DROP band type is supported. */ + if (nla_put_u32(reply, OVS_BAND_ATTR_TYPE, OVS_METER_BAND_TYPE_DROP)) + goto nla_put_failure; + nla_nest_end(reply, band_nla); + nla_nest_end(reply, nla); + + genlmsg_end(reply, ovs_reply_header); + return genlmsg_reply(reply, info); + +exit_unlock: + ovs_unlock(); +nla_put_failure: + nlmsg_free(reply); + return err; +} + +static struct dp_meter *dp_meter_create(struct nlattr **a) +{ + struct nlattr *nla; + int rem; + u16 n_bands = 0; + struct dp_meter *meter; + struct dp_meter_band *band; + int err; + + /* Validate attributes, count the bands. */ + if (!a[OVS_METER_ATTR_BANDS]) + return ERR_PTR(-EINVAL); + + nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem) + if (++n_bands > DP_MAX_BANDS) + return ERR_PTR(-EINVAL); + + /* Allocate and set up the meter before locking anything. */ + meter = kzalloc(struct_size(meter, bands, n_bands), GFP_KERNEL); + if (!meter) + return ERR_PTR(-ENOMEM); + + meter->id = nla_get_u32(a[OVS_METER_ATTR_ID]); + meter->used = div_u64(ktime_get_ns(), 1000 * 1000); + meter->kbps = a[OVS_METER_ATTR_KBPS] ? 1 : 0; + meter->keep_stats = !a[OVS_METER_ATTR_CLEAR]; + spin_lock_init(&meter->lock); + if (meter->keep_stats && a[OVS_METER_ATTR_STATS]) { + meter->stats = *(struct ovs_flow_stats *) + nla_data(a[OVS_METER_ATTR_STATS]); + } + meter->n_bands = n_bands; + + /* Set up meter bands. */ + band = meter->bands; + nla_for_each_nested(nla, a[OVS_METER_ATTR_BANDS], rem) { + struct nlattr *attr[OVS_BAND_ATTR_MAX + 1]; + u32 band_max_delta_t; + + err = nla_parse_deprecated((struct nlattr **)&attr, + OVS_BAND_ATTR_MAX, nla_data(nla), + nla_len(nla), band_policy, NULL); + if (err) + goto exit_free_meter; + + if (!attr[OVS_BAND_ATTR_TYPE] || + !attr[OVS_BAND_ATTR_RATE] || + !attr[OVS_BAND_ATTR_BURST]) { + err = -EINVAL; + goto exit_free_meter; + } + + band->type = nla_get_u32(attr[OVS_BAND_ATTR_TYPE]); + band->rate = nla_get_u32(attr[OVS_BAND_ATTR_RATE]); + if (band->rate == 0) { + err = -EINVAL; + goto exit_free_meter; + } + + band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]); + /* Figure out max delta_t that is enough to fill any bucket. + * Keep max_delta_t size to the bucket units: + * pkts => 1/1000 packets, kilobits => bits. + * + * Start with a full bucket. + */ + band->bucket = (band->burst_size + band->rate) * 1000ULL; + band_max_delta_t = div_u64(band->bucket, band->rate); + if (band_max_delta_t > meter->max_delta_t) + meter->max_delta_t = band_max_delta_t; + band++; + } + + return meter; + +exit_free_meter: + kfree(meter); + return ERR_PTR(err); +} + +static int ovs_meter_cmd_set(struct sk_buff *skb, struct genl_info *info) +{ + struct nlattr **a = info->attrs; + struct dp_meter *meter, *old_meter; + struct sk_buff *reply; + struct ovs_header *ovs_reply_header; + struct ovs_header *ovs_header = info->userhdr; + struct dp_meter_table *meter_tbl; + struct datapath *dp; + int err; + u32 meter_id; + bool failed; + + if (!a[OVS_METER_ATTR_ID]) + return -EINVAL; + + meter = dp_meter_create(a); + if (IS_ERR_OR_NULL(meter)) + return PTR_ERR(meter); + + reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_SET, + &ovs_reply_header); + if (IS_ERR(reply)) { + err = PTR_ERR(reply); + goto exit_free_meter; + } + + ovs_lock(); + dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex); + if (!dp) { + err = -ENODEV; + goto exit_unlock; + } + + meter_tbl = &dp->meter_tbl; + meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]); + + old_meter = lookup_meter(meter_tbl, meter_id); + err = detach_meter(meter_tbl, old_meter); + if (err) + goto exit_unlock; + + err = attach_meter(meter_tbl, meter); + if (err) + goto exit_free_old_meter; + + ovs_unlock(); + + /* Build response with the meter_id and stats from + * the old meter, if any. + */ + failed = nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id); + WARN_ON(failed); + if (old_meter) { + spin_lock_bh(&old_meter->lock); + if (old_meter->keep_stats) { + err = ovs_meter_cmd_reply_stats(reply, meter_id, + old_meter); + WARN_ON(err); + } + spin_unlock_bh(&old_meter->lock); + ovs_meter_free(old_meter); + } + + genlmsg_end(reply, ovs_reply_header); + return genlmsg_reply(reply, info); + +exit_free_old_meter: + ovs_meter_free(old_meter); +exit_unlock: + ovs_unlock(); + nlmsg_free(reply); +exit_free_meter: + kfree(meter); + return err; +} + +static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info) +{ + struct ovs_header *ovs_header = info->userhdr; + struct ovs_header *ovs_reply_header; + struct nlattr **a = info->attrs; + struct dp_meter *meter; + struct sk_buff *reply; + struct datapath *dp; + u32 meter_id; + int err; + + if (!a[OVS_METER_ATTR_ID]) + return -EINVAL; + + meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]); + + reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_GET, + &ovs_reply_header); + if (IS_ERR(reply)) + return PTR_ERR(reply); + + ovs_lock(); + + dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex); + if (!dp) { + err = -ENODEV; + goto exit_unlock; + } + + /* Locate meter, copy stats. */ + meter = lookup_meter(&dp->meter_tbl, meter_id); + if (!meter) { + err = -ENOENT; + goto exit_unlock; + } + + spin_lock_bh(&meter->lock); + err = ovs_meter_cmd_reply_stats(reply, meter_id, meter); + spin_unlock_bh(&meter->lock); + if (err) + goto exit_unlock; + + ovs_unlock(); + + genlmsg_end(reply, ovs_reply_header); + return genlmsg_reply(reply, info); + +exit_unlock: + ovs_unlock(); + nlmsg_free(reply); + return err; +} + +static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info) +{ + struct ovs_header *ovs_header = info->userhdr; + struct ovs_header *ovs_reply_header; + struct nlattr **a = info->attrs; + struct dp_meter *old_meter; + struct sk_buff *reply; + struct datapath *dp; + u32 meter_id; + int err; + + if (!a[OVS_METER_ATTR_ID]) + return -EINVAL; + + reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL, + &ovs_reply_header); + if (IS_ERR(reply)) + return PTR_ERR(reply); + + ovs_lock(); + + dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex); + if (!dp) { + err = -ENODEV; + goto exit_unlock; + } + + meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]); + old_meter = lookup_meter(&dp->meter_tbl, meter_id); + if (old_meter) { + spin_lock_bh(&old_meter->lock); + err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter); + WARN_ON(err); + spin_unlock_bh(&old_meter->lock); + + err = detach_meter(&dp->meter_tbl, old_meter); + if (err) + goto exit_unlock; + } + + ovs_unlock(); + ovs_meter_free(old_meter); + genlmsg_end(reply, ovs_reply_header); + return genlmsg_reply(reply, info); + +exit_unlock: + ovs_unlock(); + nlmsg_free(reply); + return err; +} + +/* Meter action execution. + * + * Return true 'meter_id' drop band is triggered. The 'skb' should be + * dropped by the caller'. + */ +bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb, + struct sw_flow_key *key, u32 meter_id) +{ + long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000); + long long int long_delta_ms; + struct dp_meter_band *band; + struct dp_meter *meter; + int i, band_exceeded_max = -1; + u32 band_exceeded_rate = 0; + u32 delta_ms; + u32 cost; + + meter = lookup_meter(&dp->meter_tbl, meter_id); + /* Do not drop the packet when there is no meter. */ + if (!meter) + return false; + + /* Lock the meter while using it. */ + spin_lock(&meter->lock); + + long_delta_ms = (now_ms - meter->used); /* ms */ + if (long_delta_ms < 0) { + /* This condition means that we have several threads fighting + * for a meter lock, and the one who received the packets a + * bit later wins. Assuming that all racing threads received + * packets at the same time to avoid overflow. + */ + long_delta_ms = 0; + } + + /* Make sure delta_ms will not be too large, so that bucket will not + * wrap around below. + */ + delta_ms = (long_delta_ms > (long long int)meter->max_delta_t) + ? meter->max_delta_t : (u32)long_delta_ms; + + /* Update meter statistics. + */ + meter->used = now_ms; + meter->stats.n_packets += 1; + meter->stats.n_bytes += skb->len; + + /* Bucket rate is either in kilobits per second, or in packets per + * second. We maintain the bucket in the units of either bits or + * 1/1000th of a packet, correspondingly. + * Then, when rate is multiplied with milliseconds, we get the + * bucket units: + * msec * kbps = bits, and + * msec * packets/sec = 1/1000 packets. + * + * 'cost' is the number of bucket units in this packet. + */ + cost = (meter->kbps) ? skb->len * 8 : 1000; + + /* Update all bands and find the one hit with the highest rate. */ + for (i = 0; i < meter->n_bands; ++i) { + long long int max_bucket_size; + + band = &meter->bands[i]; + max_bucket_size = (band->burst_size + band->rate) * 1000LL; + + band->bucket += delta_ms * band->rate; + if (band->bucket > max_bucket_size) + band->bucket = max_bucket_size; + + if (band->bucket >= cost) { + band->bucket -= cost; + } else if (band->rate > band_exceeded_rate) { + band_exceeded_rate = band->rate; + band_exceeded_max = i; + } + } + + if (band_exceeded_max >= 0) { + /* Update band statistics. */ + band = &meter->bands[band_exceeded_max]; + band->stats.n_packets += 1; + band->stats.n_bytes += skb->len; + + /* Drop band triggered, let the caller drop the 'skb'. */ + if (band->type == OVS_METER_BAND_TYPE_DROP) { + spin_unlock(&meter->lock); + return true; + } + } + + spin_unlock(&meter->lock); + return false; +} + +static const struct genl_small_ops dp_meter_genl_ops[] = { + { .cmd = OVS_METER_CMD_FEATURES, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = 0, /* OK for unprivileged users. */ + .doit = ovs_meter_cmd_features + }, + { .cmd = OVS_METER_CMD_SET, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN + * privilege. + */ + .doit = ovs_meter_cmd_set, + }, + { .cmd = OVS_METER_CMD_GET, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = 0, /* OK for unprivileged users. */ + .doit = ovs_meter_cmd_get, + }, + { .cmd = OVS_METER_CMD_DEL, + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, + .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN + * privilege. + */ + .doit = ovs_meter_cmd_del + }, +}; + +static const struct genl_multicast_group ovs_meter_multicast_group = { + .name = OVS_METER_MCGROUP, +}; + +struct genl_family dp_meter_genl_family __ro_after_init = { + .hdrsize = sizeof(struct ovs_header), + .name = OVS_METER_FAMILY, + .version = OVS_METER_VERSION, + .maxattr = OVS_METER_ATTR_MAX, + .policy = meter_policy, + .netnsok = true, + .parallel_ops = true, + .small_ops = dp_meter_genl_ops, + .n_small_ops = ARRAY_SIZE(dp_meter_genl_ops), + .mcgrps = &ovs_meter_multicast_group, + .n_mcgrps = 1, + .module = THIS_MODULE, +}; + +int ovs_meters_init(struct datapath *dp) +{ + struct dp_meter_table *tbl = &dp->meter_tbl; + struct dp_meter_instance *ti; + unsigned long free_mem_bytes; + + ti = dp_meter_instance_alloc(DP_METER_ARRAY_SIZE_MIN); + if (!ti) + return -ENOMEM; + + /* Allow meters in a datapath to use ~3.12% of physical memory. */ + free_mem_bytes = nr_free_buffer_pages() * (PAGE_SIZE >> 5); + tbl->max_meters_allowed = min(free_mem_bytes / sizeof(struct dp_meter), + DP_METER_NUM_MAX); + if (!tbl->max_meters_allowed) + goto out_err; + + rcu_assign_pointer(tbl->ti, ti); + tbl->count = 0; + + return 0; + +out_err: + dp_meter_instance_free(ti); + return -ENOMEM; +} + +void ovs_meters_exit(struct datapath *dp) +{ + struct dp_meter_table *tbl = &dp->meter_tbl; + struct dp_meter_instance *ti = rcu_dereference_raw(tbl->ti); + int i; + + for (i = 0; i < ti->n_meters; i++) + ovs_meter_free(rcu_dereference_raw(ti->dp_meters[i])); + + dp_meter_instance_free(ti); +} |