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>
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@ -17,6 +17,9 @@ enum {
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/* Match against local time (instead of UTC) */
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XT_TIME_LOCAL_TZ = 1 << 0,
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/* treat timestart > timestop (e.g. 23:00-01:00) as single period */
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XT_TIME_CONTIGUOUS = 1 << 1,
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/* Shortcuts */
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XT_TIME_ALL_MONTHDAYS = 0xFFFFFFFE,
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XT_TIME_ALL_WEEKDAYS = 0xFE,
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@ -24,4 +27,6 @@ enum {
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XT_TIME_MAX_DAYTIME = 24 * 60 * 60 - 1,
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};
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#define XT_TIME_ALL_FLAGS (XT_TIME_LOCAL_TZ|XT_TIME_CONTIGUOUS)
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#endif /* _XT_TIME_H */
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@ -42,6 +42,7 @@ static const u_int16_t days_since_leapyear[] = {
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*/
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enum {
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DSE_FIRST = 2039,
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SECONDS_PER_DAY = 86400,
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};
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static const u_int16_t days_since_epoch[] = {
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/* 2039 - 2030 */
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@ -78,7 +79,7 @@ static inline unsigned int localtime_1(struct xtm *r, time_t time)
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unsigned int v, w;
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/* Each day has 86400s, so finding the hour/minute is actually easy. */
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v = time % 86400;
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v = time % SECONDS_PER_DAY;
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r->second = v % 60;
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w = v / 60;
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r->minute = w % 60;
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@ -199,6 +200,18 @@ time_mt(const struct sk_buff *skb, struct xt_action_param *par)
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if (packet_time < info->daytime_start &&
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packet_time > info->daytime_stop)
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return false;
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/** if user asked to ignore 'next day', then e.g.
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* '1 PM Wed, August 1st' should be treated
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* like 'Tue 1 PM July 31st'.
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*
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* This also causes
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* 'Monday, "23:00 to 01:00", to match for 2 hours, starting
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* Monday 23:00 to Tuesday 01:00.
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*/
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if ((info->flags & XT_TIME_CONTIGUOUS) &&
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packet_time <= info->daytime_stop)
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stamp -= SECONDS_PER_DAY;
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}
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localtime_2(¤t_time, stamp);
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@ -227,6 +240,15 @@ static int time_mt_check(const struct xt_mtchk_param *par)
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return -EDOM;
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}
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if (info->flags & ~XT_TIME_ALL_FLAGS) {
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pr_info("unknown flags 0x%x\n", info->flags & ~XT_TIME_ALL_FLAGS);
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return -EINVAL;
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}
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if ((info->flags & XT_TIME_CONTIGUOUS) &&
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info->daytime_start < info->daytime_stop)
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return -EINVAL;
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return 0;
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}
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