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authorClaudio Jeker <claudio@cvs.openbsd.org>2005-10-12 09:51:59 +0000
committerClaudio Jeker <claudio@cvs.openbsd.org>2005-10-12 09:51:59 +0000
commit04ad4a2c4512cbf0a81ab2a93c60ae92f1ad29bb (patch)
tree35b13cd962b82710f1df4aa5aa11d106b8dcd19c
parent61a7992295b02cf6c14fb398a37382da67d92c0b (diff)
Fix the flooding procedure. Violate the RFC else many BAD_LS_REQ events and
session drops happend while booting up. If a router is conected to a other router over two different interface one session will be unable to load until the other one is in state FULL. ospfd no longer issues a BAD_LS_REQ event if the LSA is equal to the one in table but if the sent lsa is older a BAD_LS_REQ event is still issued. OK norby@
-rw-r--r--usr.sbin/ospfd/iso_cksum.c38
-rw-r--r--usr.sbin/ospfd/rde.c22
2 files changed, 40 insertions, 20 deletions
diff --git a/usr.sbin/ospfd/iso_cksum.c b/usr.sbin/ospfd/iso_cksum.c
index f3a050b37fe..de8d2c6a156 100644
--- a/usr.sbin/ospfd/iso_cksum.c
+++ b/usr.sbin/ospfd/iso_cksum.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: iso_cksum.c,v 1.1 2005/01/28 14:05:40 claudio Exp $ */
+/* $OpenBSD: iso_cksum.c,v 1.2 2005/10/12 09:51:58 claudio Exp $ */
/*
* Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
@@ -21,17 +21,18 @@
#include "ospfd.h"
#include "log.h"
+/* implementation of Fletcher Checksum -- see RFC 1008 for more info */
+
/* pos needs to be 0 for verify and 2 <= pos < len for calculation */
u_int16_t
iso_cksum(void *buf, u_int16_t len, u_int16_t pos)
{
u_int8_t *p = buf;
- int c0 = 0, c1 = 0; /* counters */
- int r0, r1; /* results */
+ int c0 = 0, c1 = 0, x; /* counters */
u_int16_t sop;
- sop = len - pos - 1; /* pos is an offset (pos 2 is at len 3) */
- p += 2;
+ sop = len - pos - 1; /* pos is an offset (pos 2 is 3rd element) */
+ p += 2; /* jump over age field */
len -= 2;
while (len--) {
c0 += *p++;
@@ -41,18 +42,27 @@ iso_cksum(void *buf, u_int16_t len, u_int16_t pos)
c0 %= 255;
c1 %= 255;
}
+#ifdef DEBUG
+ if (c0 + 256 < c0 || c1 + 256 < c1)
+ fatalx("iso_cksum: overflowed");
+#endif
}
- r0 = c0 = c0 % 255;
- r1 = c1 % 255;
if (pos) {
- r0 = ((sop * r0 - r1)) % 255;
- if (r0 <= 0)
- r0 += 255;
- r1 = 510 - r0 - c0;
- if (r1 > 255)
- r1 -= 255;
+ x = ((sop * c0 - c1)) % 255;
+ if (x <= 0)
+ x += 255;
+#if 1
+ c1 = 510 - c0 - x;
+ if (c1 > 255)
+ c1 -= 255;
+#else
+ c1 = (-c0 - x) % 255;
+ if (c1 < 0)
+ c1 += 255;
+#endif
+ c0 = x;
}
- return (r0 << 8 | r1);
+ return (c0 << 8 | c1);
}
diff --git a/usr.sbin/ospfd/rde.c b/usr.sbin/ospfd/rde.c
index f538f41cde2..200d5fc3f13 100644
--- a/usr.sbin/ospfd/rde.c
+++ b/usr.sbin/ospfd/rde.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: rde.c,v 1.29 2005/10/12 09:42:57 claudio Exp $ */
+/* $OpenBSD: rde.c,v 1.30 2005/10/12 09:51:58 claudio Exp $ */
/*
* Copyright (c) 2004, 2005 Claudio Jeker <claudio@openbsd.org>
@@ -402,20 +402,30 @@ rde_dispatch_imsg(int fd, short event, void *bula)
/* lsa not added so free it */
if (self)
free(lsa);
- } else if (rde_req_list_exists(nbr, &lsa->hdr)) {
- /* lsa no longer needed */
- free(lsa);
- imsg_compose(ibuf_ospfe, IMSG_LS_BADREQ,
- imsg.hdr.peerid, 0, -1, NULL, 0);
} else if (r < 0) {
/* lsa no longer needed */
free(lsa);
+ /*
+ * point 6 of "The Flooding Procedure"
+ * We are violating the RFC here because
+ * it does not make sense to reset a session
+ * because a equal LSA is already in the table.
+ * Only if the LSA sent is older than the one
+ * in the table we should reset the session.
+ */
+ if (rde_req_list_exists(nbr, &lsa->hdr)) {
+ imsg_compose(ibuf_ospfe, IMSG_LS_BADREQ,
+ imsg.hdr.peerid, 0, -1, NULL, 0);
+ break;
+ }
+
/* new LSA older than DB */
if (ntohl(db_hdr->seq_num) == MAX_SEQ_NUM &&
ntohs(db_hdr->age) == MAX_AGE)
/* seq-num wrap */
break;
+
if (v->changed + MIN_LS_ARRIVAL >= now)
break;