/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2020 Alexander V. Chernikov
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "opt_inet.h"
#include "opt_route.h"
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <sys/rwlock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/refcount.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/route/route_ctl.h>
#include <net/route/route_var.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_fib.h>
#include <net/route/nhop_utils.h>
#include <net/route/nhop.h>
#include <net/route/nhop_var.h>
#include <net/route/nhgrp_var.h>
#define DEBUG_MOD_NAME nhgrp
#define DEBUG_MAX_LEVEL LOG_DEBUG
#include <net/route/route_debug.h>
_DECLARE_DEBUG(LOG_INFO);
/*
* This file contains data structures management logic for the nexthop
* groups ("nhgrp") route subsystem.
*
* Nexthop groups are used to store multiple routes available for the specific
* prefix. Nexthop groups are immutable and can be shared across multiple
* prefixes.
*
* Each group consists of a control plane part and a dataplane part.
* Control plane is basically a collection of nexthop objects with
* weights and refcount.
*
* Datapath consists of a array of nexthop pointers, compiled from control
* plane data to support O(1) nexthop selection.
*
* For example, consider the following group:
* [(nh1, weight=100), (nh2, weight=200)]
* It will compile to the following array:
* [nh1, nh2, nh2]
*
*/
static void consider_resize(struct nh_control *ctl, uint32_t new_gr_buckets,
uint32_t new_idx_items);
static int cmp_nhgrp(const struct nhgrp_priv *a, const struct nhgrp_priv *b);
static unsigned int hash_nhgrp(const struct nhgrp_priv *obj);
static unsigned
djb_hash(const unsigned char *h, const int len)
{
unsigned int result = 0;
int i;
for (i = 0; i < len; i++)
result = 33 * result ^ h[i];
return (result);
}
static int
cmp_nhgrp(const struct nhgrp_priv *a, const struct nhgrp_priv *b)
{
/*
* In case of consistent hashing, there can be multiple nexthop groups
* with the same "control plane" list of nexthops with weights and a
* different set of "data plane" nexthops.
* For now, ignore the data plane and focus on the control plane list.
*/
if (a->nhg_nh_count != b->nhg_nh_count || a->nhg_uidx != b->nhg_uidx)
return (0);
return !memcmp(a->nhg_nh_weights, b->nhg_nh_weights,
sizeof(struct weightened_nhop) * a->nhg_nh_count);
}
/*
* Hash callback: calculate hash of an object
*/
static unsigned int
hash_nhgrp(const struct nhgrp_priv *obj)
{
const unsigned char *key;
key = (const unsigned char *)obj->nhg_nh_weights;
return (djb_hash(key, sizeof(struct weightened_nhop) * obj->nhg_nh_count));
}
/*
* Returns object referenced and unlocked
*/
struct nhgrp_priv *
find_nhgrp(struct nh_control *ctl, const struct nhgrp_priv *key)
{
struct nhgrp_priv *priv_ret;
NHOPS_RLOCK(ctl);
CHT_SLIST_FIND_BYOBJ(&ctl->gr_head, mpath, key, priv_ret);
if (priv_ret != NULL) {
if (refcount_acquire_if_not_zero(&priv_ret->nhg_refcount) == 0) {
/* refcount is 0 -> group is being deleted */
priv_ret = NULL;
}
}
NHOPS_RUNLOCK(ctl);
return (priv_ret);
}
int
link_nhgrp(struct nh_control *ctl, struct nhgrp_priv *grp_priv)
{
uint16_t idx;
uint32_t new_num_buckets, new_num_items;
NHOPS_WLOCK(ctl);
/* Check if we need to resize hash and index */
new_num_buckets = CHT_SLIST_GET_RESIZE_BUCKETS(&ctl->gr_head);
new_num_items = bitmask_get_resize_items(&ctl->nh_idx_head);
if (bitmask_alloc_idx(&ctl->nh_idx_head, &idx) != 0) {
NHOPS_WUNLOCK(ctl);
FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "Unable to allocate nhg index");
consider_resize(ctl, new_num_buckets, new_num_items);
return (0);
}
grp_priv->nhg_idx = idx;
grp_priv->nh_control = ctl;
CHT_SLIST_INSERT_HEAD(&ctl->gr_head, mpath, grp_priv);
NHOPS_WUNLOCK(ctl);
IF_DEBUG_LEVEL(LOG_DEBUG2) {
char nhgrp_buf[NHOP_PRINT_BUFSIZE] __unused;
FIB_RH_LOG(LOG_DEBUG2, ctl->ctl_rh, "linked %s",
nhgrp_print_buf(grp_priv->nhg, nhgrp_buf, sizeof(nhgrp_buf)));
}
consider_resize(ctl, new_num_buckets, new_num_items);
return (1);
}
struct nhgrp_priv *
unlink_nhgrp(struct nh_control *ctl, struct nhgrp_priv *key)
{
struct nhgrp_priv *nhg_priv_ret;
int idx;
NHOPS_WLOCK(ctl);
CHT_SLIST_REMOVE(&ctl->gr_head, mpath, key, nhg_priv_ret);
if (nhg_priv_ret == NULL) {
FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "Unable to find nhg");
NHOPS_WUNLOCK(ctl);
return (NULL);
}
idx = nhg_priv_ret->nhg_idx;
bitmask_free_idx(&ctl->nh_idx_head, idx);
nhg_priv_ret->nhg_idx = 0;
nhg_priv_ret->nh_control = NULL;
NHOPS_WUNLOCK(ctl);
IF_DEBUG_LEVEL(LOG_DEBUG2) {
char nhgrp_buf[NHOP_PRINT_BUFSIZE];
nhgrp_print_buf(nhg_priv_ret->nhg, nhgrp_buf, sizeof(nhgrp_buf));
FIB_RH_LOG(LOG_DEBUG2, ctl->ctl_rh, "unlinked idx#%d %s", idx,
nhgrp_buf);
}
return (nhg_priv_ret);
}
/*
* Checks if hash needs resizing and performs this resize if necessary
*
*/
static void
consider_resize(struct nh_control *ctl, uint32_t new_gr_bucket, uint32_t new_idx_items)
{
void *gr_ptr, *gr_idx_ptr;
void *old_idx_ptr;
size_t alloc_size;
gr_ptr = NULL ;
if (new_gr_bucket != 0) {
alloc_size = CHT_SLIST_GET_RESIZE_SIZE(new_gr_bucket);
gr_ptr = malloc(alloc_size, M_NHOP, M_NOWAIT | M_ZERO);
}
gr_idx_ptr = NULL;
if (new_idx_items != 0) {
alloc_size = bitmask_get_size(new_idx_items);
gr_idx_ptr = malloc(alloc_size, M_NHOP, M_NOWAIT | M_ZERO);
}
if (gr_ptr == NULL && gr_idx_ptr == NULL) {
/* Either resize is not required or allocations have failed. */
return;
}
FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh,
"going to resize nhg hash: [ptr:%p sz:%u] idx:[ptr:%p sz:%u]",
gr_ptr, new_gr_bucket, gr_idx_ptr, new_idx_items);
old_idx_ptr = NULL;
NHOPS_WLOCK(ctl);
if (gr_ptr != NULL) {
CHT_SLIST_RESIZE(&ctl->gr_head, mpath, gr_ptr, new_gr_bucket);
}
if (gr_idx_ptr != NULL) {
if (bitmask_copy(&ctl->nh_idx_head, gr_idx_ptr, new_idx_items) == 0)
bitmask_swap(&ctl->nh_idx_head, gr_idx_ptr, new_idx_items, &old_idx_ptr);
}
NHOPS_WUNLOCK(ctl);
if (gr_ptr != NULL)
free(gr_ptr, M_NHOP);
if (old_idx_ptr != NULL)
free(old_idx_ptr, M_NHOP);
}
/*
* Function allocating the necessary group data structures.
*/
bool
nhgrp_ctl_alloc_default(struct nh_control *ctl, int malloc_flags)
{
size_t alloc_size;
uint32_t num_buckets;
void *cht_ptr;
malloc_flags = (malloc_flags & (M_NOWAIT | M_WAITOK)) | M_ZERO;
num_buckets = 8;
alloc_size = CHT_SLIST_GET_RESIZE_SIZE(num_buckets);
cht_ptr = malloc(alloc_size, M_NHOP, malloc_flags);
if (cht_ptr == NULL) {
FIB_RH_LOG(LOG_WARNING, ctl->ctl_rh, "multipath init failed");
return (false);
}
NHOPS_WLOCK(ctl);
if (ctl->gr_head.hash_size == 0) {
/* Init hash and bitmask */
CHT_SLIST_INIT(&ctl->gr_head, cht_ptr, num_buckets);
NHOPS_WUNLOCK(ctl);
} else {
/* Other thread has already initiliazed hash/bitmask */
NHOPS_WUNLOCK(ctl);
free(cht_ptr, M_NHOP);
}
FIB_RH_LOG(LOG_DEBUG, ctl->ctl_rh, "multipath init done");
return (true);
}
int
nhgrp_ctl_init(struct nh_control *ctl)
{
/*
* By default, do not allocate datastructures as multipath
* routes will not be necessarily used.
*/
CHT_SLIST_INIT(&ctl->gr_head, NULL, 0);
return (0);
}
void
nhgrp_ctl_free(struct nh_control *ctl)
{
if (ctl->gr_head.ptr != NULL)
free(ctl->gr_head.ptr, M_NHOP);
}
void
nhgrp_ctl_unlink_all(struct nh_control *ctl)
{
struct nhgrp_priv *nhg_priv;
NHOPS_WLOCK_ASSERT(ctl);
CHT_SLIST_FOREACH(&ctl->gr_head, mpath, nhg_priv) {
IF_DEBUG_LEVEL(LOG_DEBUG2) {
char nhgbuf[NHOP_PRINT_BUFSIZE] __unused;
FIB_RH_LOG(LOG_DEBUG2, ctl->ctl_rh, "marking %s unlinked",
nhgrp_print_buf(nhg_priv->nhg, nhgbuf, sizeof(nhgbuf)));
}
refcount_release(&nhg_priv->nhg_linked);
} CHT_SLIST_FOREACH_END;
}
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