Add creation time to dynamic firewall rules

[David Schwartz]

	Here it is, tested and working. There were two bugs in the previous post,
pretty amazing for 7 lines of core. ;)

	Again, this patch adds the creation time to every dynamic firewall rule.
This allows you to see how stable a connection is and to estimate the
average bandwidth. A '-C' flag is added to 'ipfw' to display how much time
since the rule was created rather than how long until it expires.

	The cost is 4 bytes per dynamic firewall rule. This is consumed kernel
memory and copying when you dump the dynamic firewall rules. It also adds an
extra computation when the rules are retrieved (to relativize the time, as
is done with the expiration time).

	This patch is released under the FreeBSD license and I would like it to be
considered for inclusion in the kernel. Patch is against 5_STABLE and should
easily port to other streams. The version and time stamps are in the diff.

	Thanks.

	David Schwartz

--

--- ip_fw.h	1.89.2.2 2004/10/03 17:04:40
+++ ip_fw.h	Fri Nov 26 18:51:15 2004
@@ -353,6 +353,7 @@ struct _ipfw_dyn_rule {
 	u_int64_t	bcnt;		/* byte match counter		*/
 	struct ipfw_flow_id id;		/* (masked) flow id		*/
 	u_int32_t	expire;		/* expire time			*/
+	u_int32_t	created;	/* creation time		*/
 	u_int32_t	bucket;		/* which bucket in hash table	*/
 	u_int32_t	state;		/* state of this rule (typically a
 					 * combination of TCP flags)

--- ip_fw2.c	1.54.2.3 2004/09/17 14:49:08
+++ ip_fw2.c	Fri Nov 26 18:56:41 2004
@@ -1037,6 +1037,7 @@ add_dyn_rule(struct ipfw_flow_id *id, u_

 	r->id = *id;
 	r->expire = time_second + dyn_syn_lifetime;
+	r->created = time_second;
 	r->rule = rule;
 	r->dyn_type = dyn_type;
 	r->pcnt = r->bcnt = 0;
@@ -3089,6 +3090,9 @@ ipfw_getrules(struct ip_fw_chain *chain,
 					dst->expire =
 					    TIME_LEQ(dst->expire, time_second) ?
 						0 : dst->expire - time_second ;
+					dst->created =
+					    TIME_LEQ(time_second, dst->created) ?
+					        0 : time_second - dst->created;
 					bp += sizeof(ipfw_dyn_rule);
 				}
 			}

--- ipfw.8	1.150.2.4 2004/11/08 19:07:03
+++ ipfw.8	Fri Nov 26 18:59:20 2004
@@ -13,7 +13,7 @@
 .Cm add
 .Ar rule
 .Nm
-.Op Fl acdefnNStT
+.Op Fl acCdefnNStT
 .Brq Cm list | show
 .Op Ar rule | first-last ...
 .Nm
@@ -223,6 +223,10 @@ Implies
 When entering or showing rules, print them in compact form,
 i.e., without the optional "ip from any to any" string
 when this does not carry any additional information.
+.It Fl C
+When viewing dynamic firewall rules, print the number of
+seconds since the rule was created rather than the number
+of seconds until the rule expires.
 .It Fl d
 While listing, show dynamic rules in addition to static ones.
 .It Fl e


--- ipfw2.c	1.54.2.3 2004/09/17 14:49:08
+++ ipfw2.c	Fri Nov 26 18:57:04 2004
@@ -67,6 +67,7 @@ int
 		show_sets,		/* display rule sets */
 		test_only,		/* only check syntax */
 		comment_only,		/* only print action and comment */
+		show_created,		/* show creation time */
 		verbose;

 #define	IP_MASK_ALL	0xffffffff
@@ -1367,7 +1368,8 @@ show_dyn_ipfw(ipfw_dyn_rule *d, int pcwi
 	if (pcwidth>0 || bcwidth>0)
 	    printf(" %*llu %*llu (%ds)", pcwidth,
 		align_uint64(&d->pcnt), bcwidth,
-		align_uint64(&d->bcnt), d->expire);
+		align_uint64(&d->bcnt),
+		show_created ? d->created : d->expire);
 	switch (d->dyn_type) {
 	case O_LIMIT_PARENT:
 		printf(" PARENT %d", d->count);
@@ -3843,7 +3845,7 @@ ipfw_main(int oldac, char **oldav)
 	save_av = av;

 	optind = optreset = 0;
-	while ((ch = getopt(ac, av, "abcdefhnNqs:STtv")) != -1)
+	while ((ch = getopt(ac, av, "abcCdefhnNqs:STtv")) != -1)
 		switch (ch) {
 		case 'a':
 			do_acct = 1;
@@ -3906,7 +3908,9 @@ ipfw_main(int oldac, char **oldav)
 		case 'v': /* verbose */
 			verbose = 1;
 			break;
-
+		case 'C': /* created time */
+			show_created = 1;
+			break;
 		default:
 			free_args(save_ac, save_av);
 			return 1;