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| author | Tim Gardner <tim.gardner@canonical.com> | 2010-03-16 19:53:13 +0100 |
|---|---|---|
| committer | Patrick McHardy <kaber@trash.net> | 2010-03-17 15:53:12 +0100 |
| commit | 0079c5aee34880bcee7feee9960f0502c73dc5fa (patch) | |
| tree | a828b04c52f6650cbd654ca7b7de5ccdab5762c7 | |
| parent | 5be4a4f589841ef06fd79b241de3d5353a6c5efa (diff) | |
| download | kernel_samsung_aries-0079c5aee34880bcee7feee9960f0502c73dc5fa.zip kernel_samsung_aries-0079c5aee34880bcee7feee9960f0502c73dc5fa.tar.gz kernel_samsung_aries-0079c5aee34880bcee7feee9960f0502c73dc5fa.tar.bz2 | |
netfilter: xt_recent: add an entry reaper
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@canonical.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
| -rw-r--r-- | include/linux/netfilter/xt_recent.h | 4 | ||||
| -rw-r--r-- | 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 2ff8aae..b65eca9 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -143,6 +143,25 @@ 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) @@ -269,6 +288,10 @@ 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 || @@ -301,7 +324,10 @@ 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 " |