Date: Mon, 25 Feb 2008 06:16:20 -0200 From: Fernando Gont <fernando@gont.com.ar> To: freebsd-net@freebsd.org Subject: Ephemeral port selection (patch) Message-ID: <200802250817.m1P8HoPb024302@venus.xmundo.net>
next in thread | raw e-mail | index | archive | help
Folks,
This patch simply eliminates duplicated code in the in_pcb_bind() function.
Index: in_pcb.c
===================================================================
RCS file: /home/ncvs/src/sys/netinet/in_pcb.c,v
retrieving revision 1.198
diff -u -r1.198 in_pcb.c
--- in_pcb.c 22 Dec 2007 10:06:11 -0000 1.198
+++ in_pcb.c 25 Feb 2008 06:10:04 -0000
@@ -393,7 +393,7 @@
if (*lportp != 0)
lport = *lportp;
if (lport == 0) {
- u_short first, last;
+ u_short first, last, aux;
int count;
if (laddr.s_addr != INADDR_ANY)
@@ -440,47 +440,28 @@
/*
* Simple check to ensure all ports are not used up causing
* a deadlock here.
- *
- * We split the two cases (up and down) so that the direction
- * is not being tested on each round of the loop.
*/
if (first > last) {
- /*
- * counting down
- */
- if (dorandom)
- *lastport = first -
- (arc4random() % (first - last));
- count = first - last;
-
- do {
- if (count-- < 0) /* completely used? */
- return (EADDRNOTAVAIL);
- --*lastport;
- if (*lastport > first || *lastport < last)
- *lastport = first;
- lport = htons(*lastport);
- } while (in_pcblookup_local(pcbinfo, laddr, lport,
- wild));
- } else {
- /*
- * counting up
- */
- if (dorandom)
- *lastport = first +
- (arc4random() % (last - first));
- count = last - first;
-
- do {
- if (count-- < 0) /* completely used? */
- return (EADDRNOTAVAIL);
- ++*lastport;
- if (*lastport < first || *lastport > last)
- *lastport = first;
- lport = htons(*lastport);
- } while (in_pcblookup_local(pcbinfo, laddr, lport,
- wild));
+ aux = first;
+ first = last;
+ last = aux;
}
+
+ if (dorandom)
+ *lastport = first +
+ (arc4random() % (last - first));
+
+ count = last - first;
+
+ do {
+ if (count-- < 0) /* completely used? */
+ return (EADDRNOTAVAIL);
+ ++*lastport;
+ if (*lastport < first || *lastport > last)
+ *lastport = first;
+ lport = htons(*lastport);
+ } while (in_pcblookup_local(pcbinfo, laddr, lport,
+ wild));
}
if (prison_ip(cred, 0, &laddr.s_addr))
return (EINVAL);
--
Fernando Gont
e-mail: fernando@gont.com.ar || fgont@acm.org
PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200802250817.m1P8HoPb024302>