diff options
| 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 /net/netfilter/xt_recent.c | |
| parent | 5be4a4f589841ef06fd79b241de3d5353a6c5efa (diff) | |
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>
Diffstat (limited to 'net/netfilter/xt_recent.c')
| -rw-r--r-- | net/netfilter/xt_recent.c | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index 2ff8aae84a38..b65eca9e13a3 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 " |