Patrick, Please reference http://marc.info/?l=netfilter&m=126732834921736&w=2 for the previous discussion of this patch. Acked-by from Eric Duzamet in http://marc.info/?l=netfilter&m=126747603013790&w=2 rtg ---------------- >From f2b0624b159e3282d348cd045741725a64d71716 Mon Sep 17 00:00:00 2001 From: Tim Gardner <tim.gardner@xxxxxxxxxxxxx> Date: Sat, 27 Feb 2010 20:22:07 -0700 Subject: [PATCH] netfilter: xt_recent: Add an entry reaper (V4) One of the problems with the way xt_recent is implemented is that there is no efficient way to remove expired entries. Of course, one can write a rule '-m recent --remove', but you have to know beforehand which entry to delete. This commit adds reaper logic which checks the head of the LRU list when a rule is invoked that has a '--seconds' value and XT_RECENT_REAP set. If an entry ceases to accumulate time stamps, then it will eventually bubble to the top of the LRU list where it is then reaped. Signed-off-by: Tim Gardner <tim.gardner@xxxxxxxxxxxxx> (cherry picked from commit 3cd53e6474b307bba448103865bed63ffe81b626) --- include/linux/netfilter/xt_recent.h | 4 ++++ net/netfilter/xt_recent.c | 28 +++++++++++++++++++++++++++- 2 files changed, 31 insertions(+), 1 deletions(-) diff --git a/include/linux/netfilter/xt_recent.h b/include/linux/netfilter/xt_recent.h index d2c2766..bba990e 100644 --- a/include/linux/netfilter/xt_recent.h +++ b/include/linux/netfilter/xt_recent.h @@ -9,6 +9,7 @@ enum { XT_RECENT_UPDATE = 1 << 2, XT_RECENT_REMOVE = 1 << 3, XT_RECENT_TTL = 1 << 4, + XT_RECENT_REAP = 1 << 5, XT_RECENT_SOURCE = 0, XT_RECENT_DEST = 1, @@ -16,6 +17,9 @@ enum { XT_RECENT_NAME_LEN = 200, }; +/* Only allowed with --rcheck and --update */ +#define XT_RECENT_MODIFIERS (XT_RECENT_TTL|XT_RECENT_REAP) + struct xt_recent_mtinfo { __u32 seconds; __u32 hit_count; diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 7073dbb..873a101 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -146,6 +146,25 @@ static void recent_entry_remove(struct recent_table *t, struct recent_entry *e) t->entries--; } +/* + * Drop entries with timestamps older then 'time'. + */ +static void recent_entry_reap(struct recent_table *t, unsigned long time) +{ + struct recent_entry *e; + + /* + * The head of the LRU list is always the oldest entry. + */ + e = list_entry(t->lru_list.next, struct recent_entry, lru_list); + + /* + * The last time stamp is the most recent. + */ + if (time_after(time, e->stamps[e->index-1])) + recent_entry_remove(t, e); +} + static struct recent_entry * recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr, u_int16_t family, u_int8_t ttl) @@ -272,6 +291,10 @@ recent_mt(const struct sk_buff *skb, const struct xt_match_param *par) break; } } + + /* info->seconds must be non-zero */ + if (info->check_set & XT_RECENT_REAP) + recent_entry_reap(t, time); } if (info->check_set & XT_RECENT_SET || @@ -304,7 +327,10 @@ static bool recent_mt_check(const struct xt_mtchk_param *par) XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1) return false; if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) && - (info->seconds || info->hit_count)) + (info->seconds || info->hit_count || + (info->check_set & XT_RECENT_MODIFIERS))) + return false; + if ((info->check_set & XT_RECENT_REAP) && !info->seconds) return false; if (info->hit_count > ip_pkt_list_tot) { pr_info(KBUILD_MODNAME ": hitcount (%u) is larger than " -- 1.7.0 -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
