From 20c706d4cba3227c9c44fb61c4d93b0ae84e1464 Mon Sep 17 00:00:00 2001
From: Tim Gardner <tim.gardner@canonical.com>
Date: Mon, 1 Mar 2010 19:00:29 -0700
Subject: [PATCH] xt_recent: Added XT_RECENT_REAP logic and man page documentation

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
 extensions/libxt_recent.c           |   20 ++++++++++++++++++++
 extensions/libxt_recent.man         |    5 +++++
 include/linux/netfilter/xt_recent.h |    7 +++++++
 3 files changed, 32 insertions(+), 0 deletions(-)

--- a/extensions/libxt_recent.c
+++ b/extensions/libxt_recent.c
@@ -20,6 +20,7 @@ static const struct option recent_opts[]
 	{.name = "name",     .has_arg = true,  .val = 208},
 	{.name = "rsource",  .has_arg = false, .val = 209},
 	{.name = "rdest",    .has_arg = false, .val = 210},
+	{.name = "reap",     .has_arg = false, .val = 211},
 	XT_GETOPT_TABLEEND,
 };
 
@@ -37,6 +38,7 @@ static void recent_help(void)
 "    --hitcount hits             For check and update commands above.\n"
 "                                Specifies that the match will only occur if source address seen hits times.\n"
 "                                May be used in conjunction with the seconds option.\n"
+"    --reap                      Remove entries that have expired. Can only be used with --seconds\n"
 "    --rttl                      For check and update commands above.\n"
 "                                Specifies that the match will only occur if the source address and the TTL\n"
 "                                match between this packet and the one which was set.\n"
@@ -63,6 +65,8 @@ static void recent_init(struct xt_entry_
 	(XT_RECENT_SET | XT_RECENT_CHECK | \
 	XT_RECENT_UPDATE | XT_RECENT_REMOVE)
 
+#define XT_RECENT_SECONDS 1 << 31
+
 static int recent_parse(int c, char **argv, int invert, unsigned int *flags,
                         const void *entry, struct xt_entry_match **match)
 {
@@ -104,6 +108,7 @@ static int recent_parse(int c, char **ar
 
 		case 204:
 			info->seconds = atoi(optarg);
+			*flags |= XT_RECENT_SECONDS;
 			break;
 
 		case 205:
@@ -139,6 +144,11 @@ static int recent_parse(int c, char **ar
 			info->side = XT_RECENT_DEST;
 			break;
 
+		case 211:
+			info->check_set |= XT_RECENT_REAP;
+			*flags |= XT_RECENT_REAP;
+			break;
+
 		default:
 			return 0;
 	}
@@ -157,6 +167,12 @@ static void recent_check(unsigned int fl
 		xtables_error(PARAMETER_PROBLEM,
 		           "recent: --rttl may only be used with --rcheck or "
 		           "--update");
+	if ((flags & XT_RECENT_REAP) &&
+	    ((flags & (XT_RECENT_SET | XT_RECENT_REMOVE)) ||
+	    (!(flags & XT_RECENT_SECONDS))))
+		xtables_error(PARAMETER_PROBLEM,
+		           "recent: --reap may only be used with --rcheck or "
+		           "--update and --seconds");
 }
 
 static void recent_print(const void *ip, const struct xt_entry_match *match,
@@ -185,6 +201,8 @@ static void recent_print(const void *ip,
 		printf("side: source ");
 	if (info->side == XT_RECENT_DEST)
 		printf("side: dest ");
+	if (info->check_set & XT_RECENT_REAP)
+		printf("reap ");
 }
 
 static void recent_save(const void *ip, const struct xt_entry_match *match)
@@ -211,6 +229,8 @@ static void recent_save(const void *ip, 
 		printf("--rsource ");
 	if (info->side == XT_RECENT_DEST)
 		printf("--rdest ");
+	if (info->check_set & XT_RECENT_REAP)
+		printf("--reap ");
 }
 
 static struct xtables_match recent_mt_reg = {
--- a/extensions/libxt_recent.man
+++ b/extensions/libxt_recent.man
@@ -41,6 +41,11 @@ This option must be used in conjunction 
 \fB\-\-update\fP. When used, this will narrow the match to only happen when the
 address is in the list and was seen within the last given number of seconds.
 .TP
+\fB\-\-reap\fP \fIreap\fP
+This option must be used in conjunction with \fB\-\-seconds\fP. When used, this
+will remove entries with the most recent timestamp older then \fB\-\-seconds\fP
+since the last packet was received.
+.TP
 \fB\-\-hitcount\fP \fIhits\fP
 This option must be used in conjunction with one of \fB\-\-rcheck\fP or
 \fB\-\-update\fP. When used, this will narrow the match to only happen when the
--- a/include/linux/netfilter/xt_recent.h
+++ b/include/linux/netfilter/xt_recent.h
@@ -23,6 +23,9 @@ enum {
 #define XT_RECENT_VALID_FLAGS (XT_RECENT_CHECK|XT_RECENT_SET|XT_RECENT_UPDATE|\
 			       XT_RECENT_REMOVE|XT_RECENT_TTL|XT_RECENT_REAP)
 
+/* 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;
