Depending upon the load order of rules, the output from ip[6]tables-save
will vary, as ip[6]_tables_names is sorted LIFO. As reported by
Linus van Geuns, this makes comparing output from ip[6]tables-save across
reboots difficult. Fix this by sorting table names prior to walking
the tables, making output consistent.
This closes bugzilla #580.
Phil
Signed-off-by: Phil Oester <kernel@xxxxxxxxxxxx>
---
v2: Add option to disable sorting - feedback from Maciej Żenczykowski
diff --git a/include/xtables.h b/include/xtables.h
index c35a6e6..dc6e566 100644
--- a/include/xtables.h
+++ b/include/xtables.h
@@ -479,6 +479,8 @@ extern void xtables_ip6parse_any(const char *, struct in6_addr **,
extern void xtables_ip6parse_multiple(const char *, struct in6_addr **,
struct in6_addr **, unsigned int *);
+extern int stringcmp(const void *, const void *);
+
/**
* Print the specified value to standard output, quoting dangerous
* characters if required.
diff --git a/iptables/ip6tables-save.8 b/iptables/ip6tables-save.8
index 457be82..cc70e43 100644
--- a/iptables/ip6tables-save.8
+++ b/iptables/ip6tables-save.8
@@ -39,6 +39,10 @@ include the current values of all packet and byte counters in the output
\fB\-t\fR, \fB\-\-table\fR \fItablename\fP
restrict output to only one table. If not specified, output includes all
available tables.
+.TP
+\fB\-u\fR, \fB\-\-unsorted\fR
+by default, tables are output in alphabetical order. This option disables
+sorting, and tables are output in LIFO order.
.SH BUGS
None known as of iptables-1.2.1 release
.SH AUTHORS
diff --git a/iptables/ip6tables-save.c b/iptables/ip6tables-save.c
index d819b30..3a51fe4 100644
--- a/iptables/ip6tables-save.c
+++ b/iptables/ip6tables-save.c
@@ -9,6 +9,7 @@
#include <sys/errno.h>
#include <stdio.h>
#include <fcntl.h>
+#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
@@ -23,12 +24,14 @@
#endif
static int show_counters = 0;
+static bool sort_tables = true;
static const struct option options[] = {
{.name = "counters", .has_arg = false, .val = 'c'},
{.name = "dump", .has_arg = false, .val = 'd'},
{.name = "table", .has_arg = true, .val = 't'},
{.name = "modprobe", .has_arg = true, .val = 'M'},
+ {.name = "unsorted", .has_arg = false, .val = 'u'},
{NULL},
};
@@ -36,8 +39,9 @@ static const struct option options[] = {
/* Debugging prototype. */
static int for_each_table(int (*func)(const char *tablename))
{
- int ret = 1;
+ int i, count = 0, ret = 1;
FILE *procfile = NULL;
+ char **tables = NULL;
char tablename[XT_TABLE_MAXNAMELEN+1];
procfile = fopen("/proc/net/ip6_tables_names", "re");
@@ -50,10 +54,18 @@ static int for_each_table(int (*func)(const char *tablename))
"Badly formed tablename `%s'\n",
tablename);
tablename[strlen(tablename) - 1] = '\0';
- ret &= func(tablename);
+ count++;
+ tables = (char **)realloc(tables, sizeof(char*)*count);
+ tables[count-1] = strdup(tablename);
}
-
fclose(procfile);
+
+ if (sort_tables == true)
+ qsort(tables, count, sizeof(char *), stringcmp);
+ for (i = 0 ; i < count ; i++) {
+ ret &= func(tables[i]);
+ }
+
return ret;
}
@@ -141,7 +153,7 @@ int ip6tables_save_main(int argc, char *argv[])
init_extensions6();
#endif
- while ((c = getopt_long(argc, argv, "bcdt:", options, NULL)) != -1) {
+ while ((c = getopt_long(argc, argv, "bcdt:u", options, NULL)) != -1) {
switch (c) {
case 'c':
show_counters = 1;
@@ -154,6 +166,9 @@ int ip6tables_save_main(int argc, char *argv[])
case 'M':
xtables_modprobe_program = optarg;
break;
+ case 'u':
+ sort_tables = false;
+ break;
case 'd':
do_output(tablename);
exit(0);
diff --git a/iptables/iptables-save.8 b/iptables/iptables-save.8
index c2e0a94..862fb9d 100644
--- a/iptables/iptables-save.8
+++ b/iptables/iptables-save.8
@@ -39,6 +39,10 @@ include the current values of all packet and byte counters in the output
\fB\-t\fR, \fB\-\-table\fR \fItablename\fP
restrict output to only one table. If not specified, output includes all
available tables.
+.TP
+\fB\-u\fR, \fB\-\-unsorted\fR
+by default, tables are output in alphabetical order. This option disables
+sorting, and tables are output in LIFO order.
.SH BUGS
None known as of iptables-1.2.1 release
.SH AUTHOR
diff --git a/iptables/iptables-save.c b/iptables/iptables-save.c
index e599fce..c194d9f 100644
--- a/iptables/iptables-save.c
+++ b/iptables/iptables-save.c
@@ -9,6 +9,7 @@
#include <sys/errno.h>
#include <stdio.h>
#include <fcntl.h>
+#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
@@ -22,20 +23,23 @@
#endif
static int show_counters = 0;
+static bool sort_tables = true;
static const struct option options[] = {
{.name = "counters", .has_arg = false, .val = 'c'},
{.name = "dump", .has_arg = false, .val = 'd'},
{.name = "table", .has_arg = true, .val = 't'},
{.name = "modprobe", .has_arg = true, .val = 'M'},
+ {.name = "unsorted", .has_arg = false, .val = 'u'},
{NULL},
};
/* Debugging prototype. */
static int for_each_table(int (*func)(const char *tablename))
{
- int ret = 1;
+ int i, count = 0, ret = 1;
FILE *procfile = NULL;
+ char **tables = NULL;
char tablename[XT_TABLE_MAXNAMELEN+1];
procfile = fopen("/proc/net/ip_tables_names", "re");
@@ -48,10 +52,18 @@ static int for_each_table(int (*func)(const char *tablename))
"Badly formed tablename `%s'\n",
tablename);
tablename[strlen(tablename) - 1] = '\0';
- ret &= func(tablename);
+ count++;
+ tables = (char **)realloc(tables, sizeof(char*)*count);
+ tables[count-1] = strdup(tablename);
}
-
fclose(procfile);
+
+ if (sort_tables == true)
+ qsort(tables, count, sizeof(char *), stringcmp);
+ for (i = 0 ; i < count ; i++) {
+ ret &= func(tables[i]);
+ }
+
return ret;
}
@@ -140,7 +152,7 @@ iptables_save_main(int argc, char *argv[])
init_extensions4();
#endif
- while ((c = getopt_long(argc, argv, "bcdt:", options, NULL)) != -1) {
+ while ((c = getopt_long(argc, argv, "bcdt:u", options, NULL)) != -1) {
switch (c) {
case 'c':
show_counters = 1;
@@ -153,6 +165,9 @@ iptables_save_main(int argc, char *argv[])
case 'M':
xtables_modprobe_program = optarg;
break;
+ case 'u':
+ sort_tables = false;
+ break;
case 'd':
do_output(tablename);
exit(0);
diff --git a/libxtables/xtables.c b/libxtables/xtables.c
index ebc77b6..ca94f4e 100644
--- a/libxtables/xtables.c
+++ b/libxtables/xtables.c
@@ -1957,3 +1957,10 @@ void get_kernel_version(void)
sscanf(uts.release, "%d.%d.%d", &x, &y, &z);
kernel_version = LINUX_VERSION(x, y, z);
}
+
+int stringcmp(const void *a, const void *b)
+{
+ const char **ia = (const char **)a;
+ const char **ib = (const char **)b;
+ return strcmp(*ia, *ib);
+}
