[src/trunk]: src/sys/net RFC3032 conformance for Router Alert Label

[kefren <kefren%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bc2ebdec02e4
branches:  trunk
changeset: 790848:bc2ebdec02e4
user:      kefren <kefren%NetBSD.org@localhost>
date:      Fri Oct 25 09:25:32 2013 +0000

description:
RFC3032 conformance for Router Alert Label

diffstat:

 sys/net/if_mpls.c |  41 +++++++++++++++++++++++++++++++----------
 1 files changed, 31 insertions(+), 10 deletions(-)

diffs (83 lines):

diff -r 262f465afc64 -r bc2ebdec02e4 sys/net/if_mpls.c
--- a/sys/net/if_mpls.c Fri Oct 25 08:51:55 2013 +0000
+++ b/sys/net/if_mpls.c Fri Oct 25 09:25:32 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_mpls.c,v 1.10 2013/07/23 11:11:55 kefren Exp $ */
+/*     $NetBSD: if_mpls.c,v 1.11 2013/10/25 09:25:32 kefren Exp $ */
 
 /*
  * Copyright (c) 2010 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_mpls.c,v 1.10 2013/07/23 11:11:55 kefren Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_mpls.c,v 1.11 2013/10/25 09:25:32 kefren Exp $");
 
 #include "opt_inet.h"
 #include "opt_mpls.h"
@@ -66,6 +66,15 @@
 
 #include "if_mpls.h"
 
+#define TRIM_LABEL do { \
+       m_adj(m, sizeof(union mpls_shim)); \
+       if (m->m_len < sizeof(union mpls_shim) && \
+           (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) \
+               goto done; \
+       dst.smpls_addr.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); \
+       } while (/* CONSTCOND */ 0)
+
+
 void ifmplsattach(int);
 
 static int mpls_clone_create(struct if_clone *, int);
@@ -308,6 +317,7 @@
        struct rtentry *rt = NULL;
        int error = ENOBUFS;
        uint psize = sizeof(struct sockaddr_mpls);
+       bool push_back_alert = false;
 
        if (m->m_len < sizeof(union mpls_shim) &&
            (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)
@@ -330,14 +340,15 @@
        if (mpls_rfc4182 != 0)
                while((dst.smpls_addr.shim.label == MPLS_LABEL_IPV4NULL ||
                    dst.smpls_addr.shim.label == MPLS_LABEL_IPV6NULL) &&
-                   __predict_false(dst.smpls_addr.shim.bos == 0)) {
-                       m_adj(m, sizeof(union mpls_shim));
-                       if (m->m_len < sizeof(union mpls_shim) &&
-                           (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)
-                               goto done;
-                       dst.smpls_addr.s_addr =
-                           ntohl(mtod(m, union mpls_shim *)->s_addr);
-               }
+                   __predict_false(dst.smpls_addr.shim.bos == 0))
+                       TRIM_LABEL;
+
+       /* RFC 3032 Section 2.1 Page 4 */
+       if (__predict_false(dst.smpls_addr.shim.label == MPLS_LABEL_RTALERT) &&
+           dst.smpls_addr.shim.bos == 0) {
+               TRIM_LABEL;
+               push_back_alert = true;
+       }
 
        if (dst.smpls_addr.shim.label <= MPLS_LABEL_RESMAX) {
                /* Don't swap reserved labels */
@@ -412,6 +423,16 @@
                psize += sizeof(tshim);
        }
 
+       if (__predict_false(push_back_alert == true)) {
+               /* re-add the router alert label */
+               memset(&tshim, 0, sizeof(tshim));
+               tshim.s_addr = MPLS_LABEL_RTALERT;
+               tshim.shim.bos = tshim.shim.exp = 0;
+               tshim.shim.ttl = mpls_defttl;
+               if ((m = mpls_prepend_shim(m, &tshim)) == NULL)
+                       return ENOBUFS;
+       }
+
        error = mpls_send_frame(m, rt->rt_ifp, rt);
 
 done: