nat: Introduce a prefix lookup tree (trie) for number rewriting

* It is a trie. The max depth of the trie is the length of the
longest prefix. The lookup is O(lookuped_prefix), but as the prefix
length is limited, the lookup time is constant.

* Each node can hold the entire prefix, has place for the rewrite
  rule with up to three digits.

* A trie with 20k entries will take about 3MB ram.

* Filling the trie 100 times takes ~800ms on my i7 laptop

* 10.000.000 lookups take 315ms.. (for the same prefix).

* 93/99 lines are tested, 6/6 functions are tested, 49 of 54 branches
  are tested. Only memory allocation failures are not covered

* A late addition is to handle the '+' sign and to increase the number
  of chars in the rewrite prefix. The timing/line coverage has not
  been updated after this change.
changes/88/3188/1
Holger Hans Peter Freyther 10 years ago committed by Holger Hans Peter Freyther
parent b718ad397e
commit 85d3b34ed2
  1. 1
      openbsc/.gitignore
  2. 1
      openbsc/configure.ac
  3. 2
      openbsc/include/openbsc/Makefile.am
  4. 44
      openbsc/include/openbsc/nat_rewrite_trie.h
  5. 2
      openbsc/src/osmo-bsc_nat/Makefile.am
  6. 3
      openbsc/src/osmo-bsc_nat/bsc_nat.c
  7. 240
      openbsc/src/osmo-bsc_nat/bsc_nat_rewrite_trie.c
  8. 2
      openbsc/tests/Makefile.am
  9. 18
      openbsc/tests/bsc-nat-trie/Makefile.am
  10. 87
      openbsc/tests/bsc-nat-trie/bsc_nat_trie_test.c
  11. 20
      openbsc/tests/bsc-nat-trie/bsc_nat_trie_test.ok
  12. 25
      openbsc/tests/bsc-nat-trie/prefixes.csv
  13. 8
      openbsc/tests/testsuite.at

@ -50,6 +50,7 @@ src/osmo-bsc_nat/osmo-bsc_nat
#tests
tests/bsc-nat/bsc_nat_test
tests/bsc-nat-trie/bsc_nat_trie_test
tests/channel/channel_test
tests/db/db_test
tests/debug/debug_test

@ -157,6 +157,7 @@ AC_OUTPUT(
tests/db/Makefile
tests/channel/Makefile
tests/bsc-nat/Makefile
tests/bsc-nat-trie/Makefile
tests/mgcp/Makefile
tests/gprs/Makefile
tests/si/Makefile

@ -13,7 +13,7 @@ noinst_HEADERS = abis_nm.h abis_rsl.h db.h gsm_04_08.h gsm_data.h \
osmo_bsc_rf.h osmo_bsc.h network_listen.h bsc_nat_sccp.h \
osmo_msc_data.h osmo_bsc_grace.h sms_queue.h abis_om2000.h \
bss.h gsm_data_shared.h control_cmd.h ipaccess.h mncc_int.h \
arfcn_range_encode.h
arfcn_range_encode.h nat_rewrite_trie.h
openbsc_HEADERS = gsm_04_08.h meas_rep.h bsc_api.h
openbscdir = $(includedir)/openbsc

@ -0,0 +1,44 @@
/*
* (C) 2013 by On-Waves
* (C) 2013 by Holger Hans Peter Freyther <zecke@selfish.org>
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef NAT_REWRITE_FILE_H
#define NAT_REWRITE_FILE_H
#include <osmocom/core/linuxrbtree.h>
struct nat_rewrite_rule {
/* For digits 0-9 and + */
struct nat_rewrite_rule *rules[11];
char empty;
char prefix[14];
char rewrite[4];
};
struct nat_rewrite {
struct nat_rewrite_rule rule;
size_t prefixes;
};
struct nat_rewrite *nat_rewrite_parse(void *ctx, const char *filename);
struct nat_rewrite_rule *nat_rewrite_lookup(struct nat_rewrite *, const char *prefix);
void nat_rewrite_dump(struct nat_rewrite *rewr);
#endif

@ -7,7 +7,7 @@ bin_PROGRAMS = osmo-bsc_nat
osmo_bsc_nat_SOURCES = bsc_filter.c bsc_mgcp_utils.c bsc_nat.c bsc_nat_utils.c \
bsc_nat_vty.c bsc_sccp.c bsc_ussd.c bsc_nat_ctrl.c \
bsc_nat_rewrite.c bsc_nat_filter.c
bsc_nat_rewrite.c bsc_nat_filter.c bsc_nat_rewrite_trie.c
osmo_bsc_nat_LDADD = $(top_builddir)/src/libcommon/libcommon.a \
$(top_builddir)/src/libmgcp/libmgcp.a \
$(top_builddir)/src/libbsc/libbsc.a \

@ -1480,6 +1480,7 @@ static struct vty_app_info vty_info = {
.is_config_node = bsc_vty_is_config_node,
};
int main(int argc, char **argv)
{
int rc;
@ -1526,6 +1527,8 @@ int main(int argc, char **argv)
/* seed the PRNG */
srand(time(NULL));
/*
* Setup the MGCP code..
*/

@ -0,0 +1,240 @@
/* Handling for loading a re-write file/database */
/*
* (C) 2013 by On-Waves
* (C) 2013 by Holger Hans Peter Freyther <zecke@selfish.org>
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <openbsc/nat_rewrite_trie.h>
#include <openbsc/debug.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define CHECK_IS_DIGIT_OR_FAIL(prefix, pos) \
if (!isdigit(prefix[pos]) && prefix[pos] != '+') { \
LOGP(DNAT, LOGL_ERROR, \
"Prefix(%s) contains non ascii text at(%d=%c)\n", \
prefix, pos, prefix[pos]); \
goto fail; \
}
#define TO_INT(c) \
((c) == '+' ? 10 : ((c - '0') % 10))
static void insert_rewrite_node(struct nat_rewrite_rule *rule, struct nat_rewrite *root)
{
struct nat_rewrite_rule *new = &root->rule;
const size_t len = strlen(rule->prefix);
int i;
if (len == 0) {
LOGP(DNAT, LOGL_ERROR, "An empty prefix does not make sense.\n");
goto fail;
}
for (i = 0; i < len - 1; ++i) {
int pos;
/* check if the input is valid */
CHECK_IS_DIGIT_OR_FAIL(rule->prefix, i);
/* check if the next node is already valid */
pos = TO_INT(rule->prefix[i]);
if (!new->rules[pos]) {
new->rules[pos] = talloc_zero(root, struct nat_rewrite_rule);
if (!new->rules[pos]) {
LOGP(DNAT, LOGL_ERROR,
"Failed to allocate memory.\n");
goto fail;
}
new->rules[pos]->empty = 1;
}
/* we continue here */
new = new->rules[pos];
}
/* new now points to the place where we want to add it */
int pos;
/* check if the input is valid */
CHECK_IS_DIGIT_OR_FAIL(rule->prefix, (len - 1));
/* check if the next node is already valid */
pos = TO_INT(rule->prefix[len - 1]);
if (!new->rules[pos])
new->rules[pos] = rule;
else if (new->rules[pos]->empty) {
/* copy over entries */
new->rules[pos]->empty = 0;
memcpy(new->rules[pos]->prefix, rule->prefix, sizeof(rule->prefix));
memcpy(new->rules[pos]->rewrite, rule->rewrite, sizeof(rule->rewrite));
talloc_free(rule);
} else {
LOGP(DNAT, LOGL_ERROR,
"Prefix(%s) is already installed\n", rule->prefix);
goto fail;
}
root->prefixes += 1;
return;
fail:
talloc_free(rule);
return;
}
static void handle_line(struct nat_rewrite *rewrite, char *line)
{
char *split;
struct nat_rewrite_rule *rule;
size_t size_prefix, size_end, len;
/* Find the ',' in the line */
len = strlen(line);
split = strstr(line, ",");
if (!split) {
LOGP(DNAT, LOGL_ERROR, "Line doesn't contain ','\n");
return;
}
/* Check if there is space for the rewrite rule */
size_prefix = split - line;
if (len - size_prefix <= 2) {
LOGP(DNAT, LOGL_ERROR, "No rewrite available.\n");
return;
}
/* Continue after the ',' to the end */
split = &line[size_prefix + 1];
size_end = strlen(split) - 1;
/* Check if both strings can fit into the static array */
if (size_prefix > sizeof(rule->prefix) - 1) {
LOGP(DNAT, LOGL_ERROR,
"Prefix is too long with %zu\n", size_prefix);
return;
}
if (size_end > sizeof(rule->rewrite) - 1) {
LOGP(DNAT, LOGL_ERROR,
"Rewrite is too long with %zu on %s\n",
size_end, &line[size_prefix + 1]);
return;
}
/* Now create the entry and insert it into the trie */
rule = talloc_zero(rewrite, struct nat_rewrite_rule);
if (!rule) {
LOGP(DNAT, LOGL_ERROR, "Can not allocate memory\n");
return;
}
memcpy(rule->prefix, line, size_prefix);
assert(size_prefix < sizeof(rule->prefix));
rule->prefix[size_prefix] = '\0';
memcpy(rule->rewrite, split, size_end);
assert(size_end < sizeof(rule->rewrite));
rule->rewrite[size_end] = '\0';
/* now insert and balance the tree */
insert_rewrite_node(rule, rewrite);
}
struct nat_rewrite *nat_rewrite_parse(void *ctx, const char *filename)
{
FILE *file;
char *line = NULL;
size_t n = 2342;
struct nat_rewrite *res;
file = fopen(filename, "r");
if (!file)
return NULL;
res = talloc_zero(ctx, struct nat_rewrite);
if (!res) {
fclose(file);
return NULL;
}
/* mark the root as empty */
res->rule.empty = 1;
while (getline(&line, &n, file) != -1) {
handle_line(res, line);
}
free(line);
fclose(file);
return res;
}
/**
* Simple find that tries to do a longest match...
*/
struct nat_rewrite_rule *nat_rewrite_lookup(struct nat_rewrite *rewrite,
const char *prefix)
{
struct nat_rewrite_rule *rule = &rewrite->rule;
struct nat_rewrite_rule *last = NULL;
const int len = OSMO_MIN(strlen(prefix), (sizeof(rule->prefix) - 1));
int i;
for (i = 0; rule && i < len; ++i) {
int pos;
CHECK_IS_DIGIT_OR_FAIL(prefix, i);
pos = TO_INT(prefix[i]);
rule = rule->rules[pos];
if (rule && !rule->empty)
last = rule;
}
return last;
fail:
return NULL;
}
static void nat_rewrite_dump_rec(struct nat_rewrite_rule *rule)
{
int i;
if (!rule->empty)
printf("%s,%s\n", rule->prefix, rule->rewrite);
for (i = 0; i < ARRAY_SIZE(rule->rules); ++i) {
if (!rule->rules[i])
continue;
nat_rewrite_dump_rec(rule->rules[i]);
}
}
void nat_rewrite_dump(struct nat_rewrite *rewrite)
{
nat_rewrite_dump_rec(&rewrite->rule);
}

@ -1,7 +1,7 @@
SUBDIRS = gsm0408 db channel mgcp gprs si abis
if BUILD_NAT
SUBDIRS += bsc-nat
SUBDIRS += bsc-nat bsc-nat-trie
endif
if BUILD_SMPP

@ -0,0 +1,18 @@
AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include
AM_CFLAGS=-Wall -ggdb3 $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOSCCP_CFLAGS) $(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS)
AM_LDFLAGS = $(COVERAGE_LDFLAGS)
EXTRA_DIST = bsc_nat_trie_test.ok prefixes.csv
noinst_PROGRAMS = bsc_nat_trie_test
bsc_nat_trie_test_SOURCES = bsc_nat_trie_test.c \
$(top_srcdir)/src/osmo-bsc_nat/bsc_nat_rewrite_trie.c
bsc_nat_trie_test_LDADD = $(top_builddir)/src/libbsc/libbsc.a \
$(top_srcdir)/src/libctrl/libctrl.a \
$(top_srcdir)/src/libmgcp/libmgcp.a \
$(top_srcdir)/src/libtrau/libtrau.a \
$(top_srcdir)/src/libcommon/libcommon.a \
$(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) -lrt \
$(LIBOSMOSCCP_LIBS) $(LIBOSMOVTY_LIBS) \
$(LIBOSMOABIS_LIBS)

@ -0,0 +1,87 @@
/*
* (C) 2013 by On-Waves
* (C) 2013 by Holger Hans Peter Freyther <zecke@selfish.org>
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <openbsc/nat_rewrite_trie.h>
#include <openbsc/debug.h>
#include <osmocom/core/application.h>
#include <osmocom/core/backtrace.h>
#include <osmocom/core/talloc.h>
#include <osmocom/core/utils.h>
#include <string.h>
int main(int argc, char **argv)
{
struct nat_rewrite *trie;
osmo_init_logging(&log_info);
printf("Testing the trie\n");
trie = nat_rewrite_parse(NULL, "prefixes.csv");
OSMO_ASSERT(trie);
/* verify that it has been parsed */
OSMO_ASSERT(trie->prefixes == 17);
printf("Dumping the internal trie\n");
nat_rewrite_dump(trie);
/* now do the matching... */
OSMO_ASSERT(!nat_rewrite_lookup(trie, ""));
OSMO_ASSERT(!nat_rewrite_lookup(trie, "2"));
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1")->rewrite, "1") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12")->rewrite, "2") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "123")->rewrite, "3") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1234")->rewrite, "4") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345")->rewrite, "5") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "123456")->rewrite, "6") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1234567")->rewrite, "7") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345678")->rewrite, "8") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "123456789")->rewrite, "9") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1234567890")->rewrite, "10") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "13")->rewrite, "11") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "14")->rewrite, "12") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "15")->rewrite, "13") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "16")->rewrite, "14") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "823455")->rewrite, "15") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "82")->rewrite, "16") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "+49123445")->rewrite, "17") == 0);
/* match a prefix */
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "121")->rewrite, "2") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "1292323")->rewrite, "2") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345678901")->rewrite, "10") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "160")->rewrite, "14") == 0);
OSMO_ASSERT(strcmp(nat_rewrite_lookup(trie, "12345678901123452123123")->rewrite, "10") == 0);
/* invalid input */
OSMO_ASSERT(!nat_rewrite_lookup(trie, "12abc"));
talloc_free(trie);
trie = nat_rewrite_parse(NULL, "does_not_exist.csv");
OSMO_ASSERT(!trie);
printf("Done with the tests.\n");
return 0;
}

@ -0,0 +1,20 @@
Testing the trie
Dumping the internal trie
1,1
12,2
123,3
1234,4
12345,5
123456,6
1234567,7
12345678,8
123456789,9
1234567890,10
13,11
14,12
15,13
16,14
82,16
823455,15
+49123,17
Done with the tests.

@ -0,0 +1,25 @@
1,1
12,2
123,3
1234,4
12345,5
123456,6
1234567,7
12345678,8
123456789,9
1234567890,10
13,11
14,12
15,13
16,14
823455,15
82,16
+49123,17
1ABC,18
12345678901234567890,19
,20
14A,21
124,324324324234
1234567890,10
no line
99,
Can't render this file because it has a wrong number of fields in line 24.

@ -48,6 +48,14 @@ cat $abs_srcdir/smpp/smpp_test.err > experr
AT_CHECK([$abs_top_builddir/tests/smpp/smpp_test], [], [expout], [experr])
AT_CLEANUP
AT_SETUP([bsc-nat-trie])
AT_KEYWORDS([bsc-nat-trie])
AT_CHECK([test "$enable_nat_test" != no || exit 77])
cp $abs_srcdir/bsc-nat-trie/prefixes.csv .
cat $abs_srcdir/bsc-nat-trie/bsc_nat_trie_test.ok > expout
AT_CHECK([$abs_top_builddir/tests/bsc-nat-trie/bsc_nat_trie_test], [], [expout], [ignore])
AT_CLEANUP
AT_SETUP([si])
AT_KEYWORDS([si])
cat $abs_srcdir/si/si_test.ok > expout

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