/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/priv.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/vnet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/route/route_ctl.h>
#include <net/route/route_var.h>
#include <net/route/fib_algo.h>
/*
* Binary search lookup algo.
*
* Compiles route table into a sorted array.
* Used with small amount of routes (< 16).
* As array is immutable, it is rebuild on each rtable change.
*
* Example:
*
* 0.0.0.0/0 -> nh1
* 10.0.0.0/24 -> nh2
* 10.0.0.1/32 -> nh3
*
* gets compiled to:
*
* 0.0.0.0 -> nh1
* 10.0.0.0 -> nh2
* 10.0.0.1 -> nh3
* 10.0.0.2 -> nh2
* 10.0.1.0 -> nh1
*
*/
struct bsearch4_record {
uint32_t addr4;
uint32_t mask4;
struct nhop_object *nh;
};
struct bsearch4_data {
struct fib_data *fd;
uint32_t alloc_items;
uint32_t num_items;
void *mem;
struct bsearch4_record *rr;
struct bsearch4_record br[0];
};
/*
* Main IPv4 address lookup function.
*
* Finds array record with maximum index that is <= provided key.
* Assumes 0.0.0.0/0 always exists (may be with NULL nhop)
*/
static struct nhop_object *
bsearch4_lookup(void *algo_data, const struct flm_lookup_key key, uint32_t scopeid)
{
const struct bsearch4_data *bd = (const struct bsearch4_data *)algo_data;
const struct bsearch4_record *br;
uint32_t addr4 = ntohl(key.addr4.s_addr);
int start = 0;
int end = bd->num_items;
int i = (start + end) / 2;
while (start + 1 < end) {
i = (start + end) / 2;
br = &bd->br[i];
if (addr4 < br->addr4) {
/* key < average, reduce right boundary */
end = i;
continue;
} else if (addr4 > br->addr4) {
/* key > average, increase left aboundary */
start = i;
continue;
} else {
/* direct match */
return (br->nh);
}
}
/* start + 1 == end */
return (bd->br[start].nh);
}
/*
* Preference function.
* Assume ideal for < 10 (typical single-interface setup has 5)
* Then gradually degrade.
* Assume 30 prefixes is at least 60 records, so it will require 8 lookup,
* which is even worse than radix.
*/
static uint8_t
bsearch4_get_pref(const struct rib_rtable_info *rinfo)
{
if (rinfo->num_prefixes < 10)
return (253);
else if (rinfo->num_prefixes < 30)
return (255 - rinfo->num_prefixes * 8);
else
return (1);
}
static enum flm_op_result
bsearch4_init(uint32_t fibnum, struct fib_data *fd, void *_old_data, void **_data)
{
struct bsearch4_data *bd;
struct rib_rtable_info rinfo;
uint32_t count;
size_t sz;
void *mem;
fib_get_rtable_info(fib_get_rh(fd), &rinfo);
count = rinfo.num_prefixes * 11 / 10 + 64;
sz = sizeof(struct bsearch4_data) + sizeof(struct bsearch4_record) * count;
/* add cache line sz to ease alignment */
sz += CACHE_LINE_SIZE;
mem = malloc(sz, M_RTABLE, M_NOWAIT | M_ZERO);
if (mem == NULL)
return (FLM_REBUILD);
/* Align datapath-usable structure to cache line boundary */
bd = (struct bsearch4_data *)roundup2((uintptr_t)mem, CACHE_LINE_SIZE);
bd->mem = mem;
bd->alloc_items = count;
bd->fd = fd;
*_data = bd;
/*
* Allocate temporary array to store all rtable data.
* This step is required to provide the required prefix iteration order.
*/
bd->rr = mallocarray(count, sizeof(struct bsearch4_record), M_TEMP, M_NOWAIT | M_ZERO);
if (bd->rr == NULL)
return (FLM_REBUILD);
return (FLM_SUCCESS);
}
static void
bsearch4_destroy(void *_data)
{
struct bsearch4_data *bd = (struct bsearch4_data *)_data;
if (bd->rr != NULL)
free(bd->rr, M_TEMP);
free(bd->mem, M_RTABLE);
}
/*
* Callback storing converted rtable prefixes in the temporary array.
* Addresses are converted to a host order.
*/
static enum flm_op_result
bsearch4_add_route_cb(struct rtentry *rt, void *_data)
{
struct bsearch4_data *bd = (struct bsearch4_data *)_data;
struct bsearch4_record *rr;
struct in_addr addr4, mask4;
uint32_t scopeid;
if (bd->num_items >= bd->alloc_items)
return (FLM_REBUILD);
rr = &bd->rr[bd->num_items++];
rt_get_inet_prefix_pmask(rt, &addr4, &mask4, &scopeid);
rr->addr4 = ntohl(addr4.s_addr);
rr->mask4 = ntohl(mask4.s_addr);
rr->nh = rt_get_raw_nhop(rt);
return (FLM_SUCCESS);
}
/*
* Prefix comparison function.
* 10.0.0.0/24 < 10.0.0.0/25 <- less specific wins
* 10.0.0.0/25 < 10.0.0.1/32 <- bigger base wins
*/
static int
rr_cmp(const void *_rec1, const void *_rec2)
{
const struct bsearch4_record *rec1, *rec2;
rec1 = _rec1;
rec2 = _rec2;
if (rec1->addr4 < rec2->addr4)
return (-1);
else if (rec1->addr4 > rec2->addr4)
return (1);
/*
* wider mask value is lesser mask
* we want less specific come first, e.g. <
*/
if (rec1->mask4 < rec2->mask4)
return (-1);
else if (rec1->mask4 > rec2->mask4)
return (1);
return (0);
}
struct bsearch4_array {
uint32_t alloc_items;
uint32_t num_items;
struct bsearch4_record *arr;
};
static bool
add_array_entry(struct bsearch4_array *ba, struct bsearch4_record *br_new)
{
if (ba->num_items < ba->alloc_items) {
ba->arr[ba->num_items++] = *br_new;
return (true);
}
return (false);
}
static struct bsearch4_record *
get_last_entry(struct bsearch4_array *ba)
{
return (&ba->arr[ba->num_items - 1]);
}
/*
*
* Example:
* stack: 10.0.1.0/24,nh=3 array: 10.0.1.0/25,nh=4 -> ++10.0.1.128/24,nh=3
*
*
*/
static bool
pop_stack_entry(struct bsearch4_array *dst_array, struct bsearch4_array *stack)
{
uint32_t last_stack_addr, last_array_addr;
struct bsearch4_record *br_prev = get_last_entry(dst_array);
struct bsearch4_record *pstack = get_last_entry(stack);
/* Regardless of the result, pop stack entry */
stack->num_items--;
/* Prefix last address for the last entry in lookup array */
last_array_addr = (br_prev->addr4 | ~br_prev->mask4);
/* Prefix last address for the stack record entry */
last_stack_addr = (pstack->addr4 | ~pstack->mask4);
if (last_stack_addr > last_array_addr) {
/*
* Stack record covers > address space than
* the last entry in the lookup array.
* Add the remaining parts of a stack record to
* the lookup array.
*/
struct bsearch4_record br_new = {
.addr4 = last_array_addr + 1,
.mask4 = pstack->mask4,
.nh = pstack->nh,
};
return (add_array_entry(dst_array, &br_new));
}
return (true);
}
/*
* Updates resulting array @dst_array with a rib entry @rib_entry.
*/
static bool
bsearch4_process_record(struct bsearch4_array *dst_array,
struct bsearch4_array *stack, struct bsearch4_record *rib_entry)
{
/*
* Maintain invariant: current rib_entry is always contained
* in the top stack entry.
* Note we always have 0.0.0.0/0.
*/
while (stack->num_items > 0) {
struct bsearch4_record *pst = get_last_entry(stack);
/*
* Check if we need to pop stack.
* Rely on the ordering - larger prefixes comes up first
* Pop any entry that doesn't contain current prefix.
*/
if (pst->addr4 == (rib_entry->addr4 & pst->mask4))
break;
if (!pop_stack_entry(dst_array, stack))
return (false);
}
if (dst_array->num_items > 0) {
/*
* Check if there is a gap between previous entry and a
* current entry. Code above guarantees that both previous
* and current entry are contained in the top stack entry.
*
* Example: last: 10.0.0.1(/32,nh=3) cur: 10.0.0.3(/32,nh=4),
* stack: 10.0.0.0/24,nh=2.
* Cover a gap between previous and current by adding stack
* nexthop.
*/
struct bsearch4_record *br_tmp = get_last_entry(dst_array);
uint32_t last_declared_addr = br_tmp->addr4 | ~br_tmp->mask4;
if (last_declared_addr < rib_entry->addr4 - 1) {
/* Cover a hole */
struct bsearch4_record *pst = get_last_entry(stack);
struct bsearch4_record new_entry = {
.addr4 = last_declared_addr + 1,
.mask4 = pst->mask4,
.nh = pst->nh,
};
if (!add_array_entry(dst_array, &new_entry))
return (false);
}
/*
* Special case: adding more specific prefix at the start of
* the previous interval:
* 10.0.0.0(/24,nh=3), 10.0.0.0(/25,nh=4)
* Alter the last record, seeting new nexthop and mask.
*/
if (br_tmp->addr4 == rib_entry->addr4) {
*br_tmp = *rib_entry;
add_array_entry(stack, rib_entry);
return (true);
}
}
if (!add_array_entry(dst_array, rib_entry))
return (false);
add_array_entry(stack, rib_entry);
return (true);
}
static enum flm_op_result
bsearch4_build_array(struct bsearch4_array *dst_array, struct bsearch4_array *src_array)
{
/*
* During iteration, we keep track of all prefixes in rtable
* we currently match, by maintaining stack. As there can be only
* 32 prefixes for a single address, pre-allocate stack of size 32.
*/
struct bsearch4_array stack = {
.alloc_items = 32,
.arr = mallocarray(32, sizeof(struct bsearch4_record), M_TEMP, M_NOWAIT | M_ZERO),
};
if (stack.arr == NULL)
return (FLM_REBUILD);
for (int i = 0; i < src_array->num_items; i++) {
struct bsearch4_record *rib_entry = &src_array->arr[i];
if (!bsearch4_process_record(dst_array, &stack, rib_entry)) {
free(stack.arr, M_TEMP);
return (FLM_REBUILD);
}
}
/*
* We know that last record is contained in the top stack entry.
*/
while (stack.num_items > 0) {
if (!pop_stack_entry(dst_array, &stack))
return (FLM_REBUILD);
}
free(stack.arr, M_TEMP);
return (FLM_SUCCESS);
}
static enum flm_op_result
bsearch4_build(struct bsearch4_data *bd)
{
enum flm_op_result ret;
struct bsearch4_array prefixes_array = {
.alloc_items = bd->alloc_items,
.num_items = bd->num_items,
.arr = bd->rr,
};
/* Add default route if not exists */
bool default_found = false;
for (int i = 0; i < prefixes_array.num_items; i++) {
if (prefixes_array.arr[i].mask4 == 0) {
default_found = true;
break;
}
}
if (!default_found) {
/* Add default route with NULL nhop */
struct bsearch4_record default_entry = {};
if (!add_array_entry(&prefixes_array, &default_entry))
return (FLM_REBUILD);
}
/* Sort prefixes */
qsort(prefixes_array.arr, prefixes_array.num_items, sizeof(struct bsearch4_record), rr_cmp);
struct bsearch4_array dst_array = {
.alloc_items = bd->alloc_items,
.arr = bd->br,
};
ret = bsearch4_build_array(&dst_array, &prefixes_array);
bd->num_items = dst_array.num_items;
free(bd->rr, M_TEMP);
bd->rr = NULL;
return (ret);
}
static enum flm_op_result
bsearch4_end_dump(void *_data, struct fib_dp *dp)
{
struct bsearch4_data *bd = (struct bsearch4_data *)_data;
enum flm_op_result ret;
ret = bsearch4_build(bd);
if (ret == FLM_SUCCESS) {
dp->f = bsearch4_lookup;
dp->arg = bd;
}
return (ret);
}
static enum flm_op_result
bsearch4_change_cb(struct rib_head *rnh, struct rib_cmd_info *rc,
void *_data)
{
return (FLM_REBUILD);
}
struct fib_lookup_module flm_bsearch4= {
.flm_name = "bsearch4",
.flm_family = AF_INET,
.flm_init_cb = bsearch4_init,
.flm_destroy_cb = bsearch4_destroy,
.flm_dump_rib_item_cb = bsearch4_add_route_cb,
.flm_dump_end_cb = bsearch4_end_dump,
.flm_change_rib_item_cb = bsearch4_change_cb,
.flm_get_pref = bsearch4_get_pref,
};
/*
* Lockless radix lookup algo.
*
* Compiles immutable radix from the current routing table.
* Used with small amount of routes (<1000).
* As datastructure is immutable, it gets rebuild on each rtable change.
*
* Lookups are slightly faster as shorter lookup keys are used
* (4 bytes instead of 8 in stock radix).
*/
#define KEY_LEN_INET (offsetof(struct sockaddr_in, sin_addr) + sizeof(in_addr_t))
#define OFF_LEN_INET (8 * offsetof(struct sockaddr_in, sin_addr))
struct radix4_addr_entry {
struct radix_node rn[2];
struct sockaddr_in addr;
struct nhop_object *nhop;
};
#define LRADIX4_ITEM_SZ roundup2(sizeof(struct radix4_addr_entry), 64)
struct lradix4_data {
struct radix_node_head *rnh;
struct fib_data *fd;
void *mem;
char *rt_base;
uint32_t alloc_items;
uint32_t num_items;
};
static struct nhop_object *
lradix4_lookup(void *algo_data, const struct flm_lookup_key key, uint32_t scopeid)
{
struct radix_node_head *rnh = (struct radix_node_head *)algo_data;
struct radix4_addr_entry *ent;
struct sockaddr_in addr4 = {
.sin_len = KEY_LEN_INET,
.sin_addr = key.addr4,
};
ent = (struct radix4_addr_entry *)(rn_match(&addr4, &rnh->rh));
if (ent != NULL)
return (ent->nhop);
return (NULL);
}
/*
* Preference function.
* Assume close-to-ideal of < 10 routes (though worse than bsearch), then
* gradually degrade until 1000 routes are reached.
*/
static uint8_t
lradix4_get_pref(const struct rib_rtable_info *rinfo)
{
if (rinfo->num_prefixes < 10)
return (250);
else if (rinfo->num_prefixes < 1000)
return (254 - rinfo->num_prefixes / 4);
else
return (1);
}
static enum flm_op_result
lradix4_init(uint32_t fibnum, struct fib_data *fd, void *_old_data, void **_data)
{
struct lradix4_data *lr;
struct rib_rtable_info rinfo;
uint32_t count;
size_t sz;
lr = malloc(sizeof(struct lradix4_data), M_RTABLE, M_NOWAIT | M_ZERO);
if (lr == NULL || !rn_inithead((void **)&lr->rnh, OFF_LEN_INET))
return (FLM_REBUILD);
fib_get_rtable_info(fib_get_rh(fd), &rinfo);
count = rinfo.num_prefixes * 11 / 10;
sz = count * LRADIX4_ITEM_SZ + CACHE_LINE_SIZE;
lr->mem = malloc(sz, M_RTABLE, M_NOWAIT | M_ZERO);
if (lr->mem == NULL)
return (FLM_REBUILD);
/* Align all rtentries to a cacheline boundary */
lr->rt_base = (char *)roundup2((uintptr_t)lr->mem, CACHE_LINE_SIZE);
lr->alloc_items = count;
lr->fd = fd;
*_data = lr;
return (FLM_SUCCESS);
}
static void
lradix4_destroy(void *_data)
{
struct lradix4_data *lr = (struct lradix4_data *)_data;
if (lr->rnh != NULL)
rn_detachhead((void **)&lr->rnh);
if (lr->mem != NULL)
free(lr->mem, M_RTABLE);
free(lr, M_RTABLE);
}
static enum flm_op_result
lradix4_add_route_cb(struct rtentry *rt, void *_data)
{
struct lradix4_data *lr = (struct lradix4_data *)_data;
struct radix4_addr_entry *ae;
struct sockaddr_in mask;
struct sockaddr *rt_mask;
struct radix_node *rn;
struct in_addr addr4, mask4;
uint32_t scopeid;
if (lr->num_items >= lr->alloc_items)
return (FLM_REBUILD);
ae = (struct radix4_addr_entry *)(lr->rt_base + lr->num_items * LRADIX4_ITEM_SZ);
lr->num_items++;
ae->nhop = rt_get_raw_nhop(rt);
rt_get_inet_prefix_pmask(rt, &addr4, &mask4, &scopeid);
ae->addr.sin_len = KEY_LEN_INET;
ae->addr.sin_addr = addr4;
if (mask4.s_addr != INADDR_BROADCAST) {
bzero(&mask, sizeof(mask));
mask.sin_len = KEY_LEN_INET;
mask.sin_addr = mask4;
rt_mask = (struct sockaddr *)&mask;
} else
rt_mask = NULL;
rn = lr->rnh->rnh_addaddr((struct sockaddr *)&ae->addr, rt_mask,
&lr->rnh->rh, ae->rn);
if (rn == NULL)
return (FLM_REBUILD);
return (FLM_SUCCESS);
}
static enum flm_op_result
lradix4_end_dump(void *_data, struct fib_dp *dp)
{
struct lradix4_data *lr = (struct lradix4_data *)_data;
dp->f = lradix4_lookup;
dp->arg = lr->rnh;
return (FLM_SUCCESS);
}
static enum flm_op_result
lradix4_change_cb(struct rib_head *rnh, struct rib_cmd_info *rc,
void *_data)
{
return (FLM_REBUILD);
}
struct fib_lookup_module flm_radix4_lockless = {
.flm_name = "radix4_lockless",
.flm_family = AF_INET,
.flm_init_cb = lradix4_init,
.flm_destroy_cb = lradix4_destroy,
.flm_dump_rib_item_cb = lradix4_add_route_cb,
.flm_dump_end_cb = lradix4_end_dump,
.flm_change_rib_item_cb = lradix4_change_cb,
.flm_get_pref = lradix4_get_pref,
};
/*
* Fallback lookup algorithm.
* This is a simple wrapper around system radix.
*/
struct radix4_data {
struct fib_data *fd;
struct rib_head *rh;
};
static struct nhop_object *
radix4_lookup(void *algo_data, const struct flm_lookup_key key, uint32_t scopeid)
{
RIB_RLOCK_TRACKER;
struct rib_head *rh = (struct rib_head *)algo_data;
struct radix_node *rn;
struct nhop_object *nh;
/* Prepare lookup key */
struct sockaddr_in sin4 = {
.sin_family = AF_INET,
.sin_len = sizeof(struct sockaddr_in),
.sin_addr = key.addr4,
};
nh = NULL;
RIB_RLOCK(rh);
rn = rn_match((void *)&sin4, &rh->head);
if (rn != NULL && ((rn->rn_flags & RNF_ROOT) == 0))
nh = (RNTORT(rn))->rt_nhop;
RIB_RUNLOCK(rh);
return (nh);
}
static uint8_t
radix4_get_pref(const struct rib_rtable_info *rinfo)
{
return (50);
}
static enum flm_op_result
radix4_init(uint32_t fibnum, struct fib_data *fd, void *_old_data, void **_data)
{
struct radix4_data *r4;
r4 = malloc(sizeof(struct radix4_data), M_RTABLE, M_NOWAIT | M_ZERO);
if (r4 == NULL)
return (FLM_REBUILD);
r4->fd = fd;
r4->rh = fib_get_rh(fd);
*_data = r4;
return (FLM_SUCCESS);
}
static void
radix4_destroy(void *_data)
{
free(_data, M_RTABLE);
}
static enum flm_op_result
radix4_add_route_cb(struct rtentry *rt, void *_data)
{
return (FLM_SUCCESS);
}
static enum flm_op_result
radix4_end_dump(void *_data, struct fib_dp *dp)
{
struct radix4_data *r4 = (struct radix4_data *)_data;
dp->f = radix4_lookup;
dp->arg = r4->rh;
return (FLM_SUCCESS);
}
static enum flm_op_result
radix4_change_cb(struct rib_head *rnh, struct rib_cmd_info *rc,
void *_data)
{
return (FLM_SUCCESS);
}
struct fib_lookup_module flm_radix4 = {
.flm_name = "radix4",
.flm_family = AF_INET,
.flm_init_cb = radix4_init,
.flm_destroy_cb = radix4_destroy,
.flm_dump_rib_item_cb = radix4_add_route_cb,
.flm_dump_end_cb = radix4_end_dump,
.flm_change_rib_item_cb = radix4_change_cb,
.flm_get_pref = radix4_get_pref,
};
static void
fib4_algo_init(void)
{
fib_module_register(&flm_bsearch4);
fib_module_register(&flm_radix4_lockless);
fib_module_register(&flm_radix4);
}
SYSINIT(fib4_algo_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, fib4_algo_init, NULL);
