Merge pull request #6231 from dslicenc/v6-ra-hoplimit

zebra: add ability to set hoplimit for IPv6 RAs

doc/user/ipv6.rst

@@ -90,6 +90,17 @@ Router Advertisement
    and neighbor establishment.
    Default: enabled
 
+.. index::
+   single: ipv6 nd ra-hop-limit (0-255)
+   single: no ipv6 nd ra-hop-limit [(0-255)]
+.. clicmd:: [no] ipv6 nd ra-hop-limit [(0-255)]
+
+   The value to be placed in the hop count field of router advertisements sent
+   from the interface, in hops. Indicates the maximum diameter of the network.
+   Setting the value to zero indicates that the value is unspecified by this
+   router.  Must be between zero or 255 hops.
+   Default: ``64``
+
 .. index::
    single: ipv6 nd ra-lifetime (0-9000)
    single: no ipv6 nd ra-lifetime [(0-9000)]

zebra/interface.c

@@ -153,7 +153,7 @@ static int if_zebra_new_hook(struct interface *ifp)
 		rtadv->AdvLinkMTU = 0;
 		rtadv->AdvReachableTime = 0;
 		rtadv->AdvRetransTimer = 0;
-		rtadv->AdvCurHopLimit = 0;
+		rtadv->AdvCurHopLimit = RTADV_DEFAULT_HOPLIMIT;
 		rtadv->AdvDefaultLifetime =
 			-1; /* derive from MaxRtrAdvInterval */
 		rtadv->HomeAgentPreference = 0;

zebra/interface.h

@@ -117,6 +117,7 @@ struct rtadvconf {
 	   Default: The value specified in the "Assigned Numbers" RFC
 	   [ASSIGNED] that was in effect at the time of implementation. */
 	int AdvCurHopLimit;
+#define RTADV_DEFAULT_HOPLIMIT 64 /* 64 hops */
 
 	/* The value to be placed in the Router Lifetime field of Router
 	   Advertisements sent from the interface, in seconds.  MUST be

zebra/rtadv.c

@@ -46,6 +46,10 @@
 #include "zebra/zebra_errors.h"
 #include "zebra/zebra_router.h"
 
+#ifndef VTYSH_EXTRACT_PL
+#include "zebra/rtadv_clippy.c"
+#endif
+
 extern struct zebra_privs_t zserv_privs;
 
 #if defined(HAVE_RTADV)
@@ -230,7 +234,7 @@ static void rtadv_send_packet(int sock, struct interface *ifp,
 	rtadv->nd_ra_code = 0;
 	rtadv->nd_ra_cksum = 0;
 
-	rtadv->nd_ra_curhoplimit = 64;
+	rtadv->nd_ra_curhoplimit = zif->rtadv.AdvCurHopLimit;
 
 	/* RFC4191: Default Router Preference is 0 if Router Lifetime is 0. */
 	rtadv->nd_ra_flags_reserved = zif->rtadv.AdvDefaultLifetime == 0
@@ -1231,6 +1235,53 @@ DEFUN (no_ipv6_nd_ra_fast_retrans,
 	return CMD_SUCCESS;
 }
 
+DEFPY (ipv6_nd_ra_hop_limit,
+       ipv6_nd_ra_hop_limit_cmd,
+       "ipv6 nd ra-hop-limit (0-255)$hopcount",
+       "Interface IPv6 config commands\n"
+       "Neighbor discovery\n"
+       "Advertisement Hop Limit\n"
+       "Advertisement Hop Limit in hops (default:64)\n")
+{
+	VTY_DECLVAR_CONTEXT(interface, ifp);
+	struct zebra_if *zif = ifp->info;
+
+	if (if_is_loopback(ifp)
+	    || CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_VRF_LOOPBACK)) {
+		vty_out(vty,
+			"Cannot configure IPv6 Router Advertisements on this interface\n");
+		return CMD_WARNING_CONFIG_FAILED;
+	}
+
+	zif->rtadv.AdvCurHopLimit = hopcount;
+
+	return CMD_SUCCESS;
+}
+
+DEFPY (no_ipv6_nd_ra_hop_limit,
+       no_ipv6_nd_ra_hop_limit_cmd,
+       "no ipv6 nd ra-hop-limit [(0-255)]",
+       NO_STR
+       "Interface IPv6 config commands\n"
+       "Neighbor discovery\n"
+       "Advertisement Hop Limit\n"
+       "Advertisement Hop Limit in hops\n")
+{
+	VTY_DECLVAR_CONTEXT(interface, ifp);
+	struct zebra_if *zif = ifp->info;
+
+	if (if_is_loopback(ifp)
+	    || CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_VRF_LOOPBACK)) {
+		vty_out(vty,
+			"Cannot configure IPv6 Router Advertisements on this interface\n");
+		return CMD_WARNING_CONFIG_FAILED;
+	}
+
+	zif->rtadv.AdvCurHopLimit = RTADV_DEFAULT_HOPLIMIT;
+
+	return CMD_SUCCESS;
+}
+
 DEFUN (ipv6_nd_suppress_ra,
        ipv6_nd_suppress_ra_cmd,
        "ipv6 nd suppress-ra",
@@ -2178,6 +2229,8 @@ static int nd_dump_vty(struct vty *vty, struct interface *ifp)
 		vty_out(vty,
 			"  ND advertised retransmit interval is %d milliseconds\n",
 			rtadv->AdvRetransTimer);
+		vty_out(vty, "  ND advertised hop-count limit is %d hops\n",
+			rtadv->AdvCurHopLimit);
 		vty_out(vty, "  ND router advertisements sent: %d rcvd: %d\n",
 			zif->ra_sent, zif->ra_rcvd);
 		interval = rtadv->MaxRtrAdvInterval;
@@ -2269,6 +2322,10 @@ static int rtadv_config_write(struct vty *vty, struct interface *ifp)
 	if (!zif->rtadv.UseFastRexmit)
 		vty_out(vty, " no ipv6 nd ra-fast-retrans\n");
 
+	if (zif->rtadv.AdvCurHopLimit != RTADV_DEFAULT_HOPLIMIT)
+		vty_out(vty, " ipv6 nd ra-hop-limit %d\n",
+			zif->rtadv.AdvCurHopLimit);
+
 	if (zif->rtadv.AdvDefaultLifetime != -1)
 		vty_out(vty, " ipv6 nd ra-lifetime %d\n",
 			zif->rtadv.AdvDefaultLifetime);
@@ -2437,6 +2494,8 @@ void rtadv_cmd_init(void)
 
 	install_element(INTERFACE_NODE, &ipv6_nd_ra_fast_retrans_cmd);
 	install_element(INTERFACE_NODE, &no_ipv6_nd_ra_fast_retrans_cmd);
+	install_element(INTERFACE_NODE, &ipv6_nd_ra_hop_limit_cmd);
+	install_element(INTERFACE_NODE, &no_ipv6_nd_ra_hop_limit_cmd);
 	install_element(INTERFACE_NODE, &ipv6_nd_suppress_ra_cmd);
 	install_element(INTERFACE_NODE, &no_ipv6_nd_suppress_ra_cmd);
 	install_element(INTERFACE_NODE, &ipv6_nd_ra_interval_cmd);

zebra/subdir.am

@@ -123,6 +123,9 @@ zebra/zebra_vty.$(OBJEXT): zebra/zebra_vty_clippy.c
 zebra/zebra_routemap_clippy.c: $(CLIPPY_DEPS)
 zebra/zebra_routemap.$(OBJEXT): zebra/zebra_routemap_clippy.c
 
+zebra/rtadv_clippy.c: $(CLIPPY_DEPS)
+zebra/rtadv.$(OBJEXT): zebra/rtadv_clippy.c
+
 noinst_HEADERS += \
 	zebra/connected.h \
 	zebra/debug.h \