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/*
* Copyright (c) 2018 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "lpm.h"
#include <vnet/ip/ip4_packet.h>
#include <vnet/ip/ip6_packet.h>
#include <arpa/inet.h>
#include <vnet/ip/format.h>
static uint32_t
masked_address32 (uint32_t addr, uint8_t len)
{
u32 a = ntohl(addr);
return htonl(len == 32 ? a : a & ~(~0u >> len));
}
static uint64_t
masked_address64 (uint64_t addr, uint8_t len)
{
/* This was originally causing non-64-bit masks to not match due to LSB vs
* MSB masking (0s at the head of the value) Probably needs some corner case
* checking in case my masking logic was off [dgeist]
*
* return len == 64 ? addr : addr & ~(~0ull >> len);
*/
return len == 64 ? addr : addr & ((1ull << (len)) - 1);
}
static void
lpm_32_add (lpm_t *lpm, void *addr_v, u8 pfxlen,
u32 value)
{
uword * hash, * result;
u32 key;
ip4_address_t *addr = addr_v;
key = masked_address32(addr->data_u32, pfxlen);
hash = lpm->hash[pfxlen];
result = hash_get (hash, key);
if (result) /* Entry exists */
clib_warning("%U/%d already exists in table for domain %d",
format_ip4_address, addr, pfxlen, result[0]);
/*
* adding a new entry
*/
if (hash == NULL) {
hash = hash_create (32 /* elts */, sizeof (uword));
hash_set_flags (hash, HASH_FLAG_NO_AUTO_SHRINK);
}
hash = hash_set(hash, key, value);
lpm->hash[pfxlen] = hash;
}
static void
lpm_32_delete (lpm_t *lpm, void *addr_v, u8 pfxlen)
{
uword * hash, * result;
u32 key;
ip4_address_t *addr = addr_v;
key = masked_address32(addr->data_u32, pfxlen);
hash = lpm->hash[pfxlen];
result = hash_get (hash, key);
if (result)
hash_unset(hash, key);
lpm->hash[pfxlen] = hash;
}
static u32
lpm_32_lookup (lpm_t *lpm, void *addr_v, u8 pfxlen)
{
uword * hash, * result;
i32 mask_len;
u32 key;
ip4_address_t *addr = addr_v;
for (mask_len = pfxlen; mask_len >= 0; mask_len--) {
hash = lpm->hash[mask_len];
if (hash) {
key = masked_address32(addr->data_u32, mask_len);
result = hash_get (hash, key);
if (result != NULL) {
return (result[0]);
}
}
}
return (~0);
}
static int
lpm_128_lookup_core (lpm_t *lpm, ip6_address_t *addr, u8 pfxlen, u32 *value)
{
BVT(clib_bihash_kv) kv, v;
int rv;
kv.key[0] = masked_address64(addr->as_u64[0], pfxlen > 64 ? 64 : pfxlen);
kv.key[1] = masked_address64(addr->as_u64[1], pfxlen > 64 ? pfxlen - 64 : 0);
kv.key[2] = pfxlen;
rv = BV(clib_bihash_search_inline_2)(&lpm->bihash, &kv, &v);
if (rv != 0)
return -1;
*value = v.value;
return 0;
}
static u32
lpm_128_lookup (lpm_t *lpm, void *addr_v, u8 pfxlen)
{
ip6_address_t *addr = addr_v;
int i = 0, rv;
u32 value;
clib_bitmap_foreach (i, lpm->prefix_lengths_bitmap)
{
rv = lpm_128_lookup_core(lpm, addr, i, &value);
if (rv == 0)
return value;
}
return ~0;
}
static void
lpm_128_add (lpm_t *lpm, void *addr_v, u8 pfxlen, u32 value)
{
BVT(clib_bihash_kv) kv;
ip6_address_t *addr = addr_v;
/* This is a quick hack. It works for pfxlen < 64 but needs validation for
* other [dgeist]
*
* kv.key[0] = masked_address64(addr->as_u64[0], pfxlen > 64 ? 64 : pfxlen);
*/
kv.key[0] = masked_address64 (addr->as_u64[0], pfxlen > 64 ? 64 : 64);
kv.key[1] = masked_address64(addr->as_u64[1], pfxlen > 64 ? pfxlen - 64 : 0);
kv.key[2] = pfxlen;
kv.value = value;
BV(clib_bihash_add_del)(&lpm->bihash, &kv, 1);
lpm->prefix_length_refcount[pfxlen]++;
/* Populating the lengths bitmap table with prefix of 48 instead of 80
* (128 - 48) [dgeist]
*
* lpm->prefix_lengths_bitmap = clib_bitmap_set (
* lpm->prefix_lengths_bitmap, 128 - pfxlen, 1);
*/
lpm->prefix_lengths_bitmap = clib_bitmap_set (
lpm->prefix_lengths_bitmap, pfxlen > 64 ? 128 - pfxlen : pfxlen, 1);
}
static void
lpm_128_delete (lpm_t *lpm, void *addr_v, u8 pfxlen)
{
ip6_address_t *addr = addr_v;
BVT(clib_bihash_kv) kv;
kv.key[0] = masked_address64(addr->as_u64[0], pfxlen > 64 ? 64 : pfxlen);
kv.key[1] = masked_address64(addr->as_u64[1], pfxlen > 64 ? pfxlen - 64 : 0);
kv.key[2] = pfxlen;
BV(clib_bihash_add_del)(&lpm->bihash, &kv, 0);
/* refcount accounting */
ASSERT (lpm->prefix_length_refcount[pfxlen] > 0);
if (--lpm->prefix_length_refcount[pfxlen] == 0) {
lpm->prefix_lengths_bitmap =
clib_bitmap_set (lpm->prefix_lengths_bitmap, 128 - pfxlen, 0);
}
}
lpm_t *
lpm_table_init (enum lpm_type_e lpm_type)
{
lpm_t * lpm = clib_mem_alloc(sizeof(*lpm));
memset(lpm, 0, sizeof(*lpm));
switch (lpm_type) {
case LPM_TYPE_KEY32:
lpm->add = lpm_32_add;
lpm->delete = lpm_32_delete;
lpm->lookup = lpm_32_lookup;
break;
case LPM_TYPE_KEY128:
lpm->add = lpm_128_add;
lpm->delete = lpm_128_delete;
lpm->lookup = lpm_128_lookup;
/* Make bihash sizes configurable */
BV (clib_bihash_init) (&(lpm->bihash),
"LPM 128", 64*1024, 32<<20);
break;
default:
ASSERT(0);
}
return lpm;
}
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