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netfilter: xt_time: add support to ignore day transition 

Currently, if you want to do something like:
"match Monday, starting 23:00, for two hours"
You need two rules, one for Mon 23:00 to 0:00 and one for Tue 0:00-1:00.

The rule: --weekdays Mo --timestart 23:00  --timestop 01:00

looks correct, but it will first match on monday from midnight to 1 a.m.
and then again for another hour from 23:00 onwards.

This permits userspace to explicitly ignore the day transition and
match for a single, continuous time period instead.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2012-09-17 00:23:09 +00:00 committed by Pablo Neira Ayuso
parent 3e0304a583
commit 54eb3df3a7
2 changed files with 28 additions and 1 deletions
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5
include/linux/netfilter/xt_time.h
View File

@ -17,6 +17,9 @@ enum {
/* Match against local time (instead of UTC) */
XT_TIME_LOCAL_TZ = 1 << 0,
/* treat timestart > timestop (e.g. 23:00-01:00) as single period */
XT_TIME_CONTIGUOUS = 1 << 1,
/* Shortcuts */
XT_TIME_ALL_MONTHDAYS = 0xFFFFFFFE,
XT_TIME_ALL_WEEKDAYS = 0xFE,
@ -24,4 +27,6 @@ enum {
XT_TIME_MAX_DAYTIME = 24 * 60 * 60 - 1,
};
#define XT_TIME_ALL_FLAGS (XT_TIME_LOCAL_TZ|XT_TIME_CONTIGUOUS)
#endif /* _XT_TIME_H */

24
net/netfilter/xt_time.c
View File

@ -42,6 +42,7 @@ static const u_int16_t days_since_leapyear[] = {
*/
enum {
DSE_FIRST = 2039,
SECONDS_PER_DAY = 86400,
};
static const u_int16_t days_since_epoch[] = {
/* 2039 - 2030 */
@ -78,7 +79,7 @@ static inline unsigned int localtime_1(struct xtm *r, time_t time)
unsigned int v, w;
/* Each day has 86400s, so finding the hour/minute is actually easy. */
v = time % 86400;
v = time % SECONDS_PER_DAY;
r->second = v % 60;
w = v / 60;
r->minute = w % 60;
@ -199,6 +200,18 @@ time_mt(const struct sk_buff *skb, struct xt_action_param *par)
if (packet_time < info->daytime_start &&
packet_time > info->daytime_stop)
return false;
/** if user asked to ignore 'next day', then e.g.
* '1 PM Wed, August 1st' should be treated
* like 'Tue 1 PM July 31st'.
*
* This also causes
* 'Monday, "23:00 to 01:00", to match for 2 hours, starting
* Monday 23:00 to Tuesday 01:00.
*/
if ((info->flags & XT_TIME_CONTIGUOUS) &&
packet_time <= info->daytime_stop)
stamp -= SECONDS_PER_DAY;
}
localtime_2(&current_time, stamp);
@ -227,6 +240,15 @@ static int time_mt_check(const struct xt_mtchk_param *par)
return -EDOM;
}
if (info->flags & ~XT_TIME_ALL_FLAGS) {
pr_info("unknown flags 0x%x\n", info->flags & ~XT_TIME_ALL_FLAGS);
return -EINVAL;
}
if ((info->flags & XT_TIME_CONTIGUOUS) &&
info->daytime_start < info->daytime_stop)
return -EINVAL;
return 0;
}