pimd: Do not allow to configure multicast on more than MAXVIF interfaces

RCA: When configured more than 32(MAXVIS), the inerfaces that are configured
after 32nd interfaces have the value of MAXVIF.
This is used as index to access the free vif tracker of array size 32(MAXVIFS).
So the channel oil list pointer which is present as the next field in pim structure get corrupt, when updating free vif.
This gets accessed during rpf update resulting in crash.

Fix: Refrain from allocating mcast interface structure and throw config error when more than MAXVIFS are attempted to configure.
Max vif checks are exempted for vrf device and pimreg as vrf device will be the first interface and not expected to fail and pimreg has reserved vif.
vxlan tunnel termination device creation has this check and throw warning on max vif.
All other creation are through CLI.

Signed-off-by: Saravanan K <saravanank@vmware.com>

1 files changed, 53 insertions, 22 deletions

diff --git a/pimd/pim_cmd.c b/pimd/pim_cmd.c
index abc1548967..193dcb8fc0 100644
--- a/pimd/pim_cmd.c
+++ b/pimd/pim_cmd.c
@@ -7237,11 +7237,20 @@ DEFUN (no_ip_pim_ecmp_rebalance,
 static int pim_cmd_igmp_start(struct vty *vty, struct interface *ifp)
 {
 	struct pim_interface *pim_ifp;
+	struct pim_instance *pim;
 	uint8_t need_startup = 0;
 
 	pim_ifp = ifp->info;
 
 	if (!pim_ifp) {
+		pim = pim_get_pim_instance(ifp->vrf_id);
+		/* Limit mcast interfaces to number of vifs available */
+		if (pim->mcast_if_count == MAXVIFS) {
+			vty_out(vty,
+				"Max multicast interfaces(%d) Reached. Could not enable IGMP on interface %s\n",
+				MAXVIFS, ifp->name);
+			return CMD_WARNING_CONFIG_FAILED;
+		}
 		(void)pim_if_new(ifp, true, false, false, false);
 		need_startup = 1;
 	} else {
@@ -7991,13 +8000,21 @@ DEFPY_HIDDEN (interface_ip_igmp_query_generate,
 	return CMD_SUCCESS;
 }
 
-static int pim_cmd_interface_add(struct interface *ifp)
+static int pim_cmd_interface_add(struct vty *vty, struct interface *ifp)
 {
 	struct pim_interface *pim_ifp = ifp->info;
+	struct pim_instance *pim;
 
-	if (!pim_ifp)
+	if (!pim_ifp) {
+		pim = pim_get_pim_instance(ifp->vrf_id);
+		/* Limiting mcast interfaces to number of VIFs */
+		if (pim->mcast_if_count == MAXVIFS) {
+			vty_out(vty, "Max multicast interfaces(%d) reached.",
+				MAXVIFS);
+			return 0;
+		}
 		pim_ifp = pim_if_new(ifp, false, true, false, false);
-	else
+	} else
 		PIM_IF_DO_PIM(pim_ifp->options);
 
 	pim_if_addr_add_all(ifp);
@@ -8068,15 +8085,17 @@ DEFPY (interface_ip_pim_activeactive,
 	VTY_DECLVAR_CONTEXT(interface, ifp);
 	struct pim_interface *pim_ifp;
 
-	if (!no && !pim_cmd_interface_add(ifp)) {
-		vty_out(vty, "Could not enable PIM SM active-active on interface\n");
+	if (!no && !pim_cmd_interface_add(vty, ifp)) {
+		vty_out(vty,
+			"Could not enable PIM SM active-active on interface %s\n",
+			ifp->name);
 		return CMD_WARNING_CONFIG_FAILED;
 	}
 
 
-        if (PIM_DEBUG_MLAG)
-                zlog_debug("%sConfiguring PIM active-active on Interface: %s",
-                           no ? "Un-":" ", ifp->name);
+	if (PIM_DEBUG_MLAG)
+		zlog_debug("%sConfiguring PIM active-active on Interface: %s",
+			   no ? "Un-" : " ", ifp->name);
 
 	pim_ifp = ifp->info;
 	if (no)
@@ -8096,8 +8115,9 @@ DEFUN_HIDDEN (interface_ip_pim_ssm,
 {
 	VTY_DECLVAR_CONTEXT(interface, ifp);
 
-	if (!pim_cmd_interface_add(ifp)) {
-		vty_out(vty, "Could not enable PIM SM on interface\n");
+	if (!pim_cmd_interface_add(vty, ifp)) {
+		vty_out(vty, "Could not enable PIM SM on interface %s\n",
+			ifp->name);
 		return CMD_WARNING_CONFIG_FAILED;
 	}
 
@@ -8113,8 +8133,9 @@ static int interface_ip_pim_helper(struct vty *vty)
 
 	VTY_DECLVAR_CONTEXT(interface, ifp);
 
-	if (!pim_cmd_interface_add(ifp)) {
-		vty_out(vty, "Could not enable PIM SM on interface\n");
+	if (!pim_cmd_interface_add(vty, ifp)) {
+		vty_out(vty, "Could not enable PIM SM on interface %s\n",
+			ifp->name);
 		return CMD_WARNING_CONFIG_FAILED;
 	}
 
@@ -8402,8 +8423,10 @@ DEFUN (interface_ip_pim_hello,
 	struct pim_interface *pim_ifp = ifp->info;
 
 	if (!pim_ifp) {
-		if (!pim_cmd_interface_add(ifp)) {
-			vty_out(vty, "Could not enable PIM SM on interface\n");
+		if (!pim_cmd_interface_add(vty, ifp)) {
+			vty_out(vty,
+				"Could not enable PIM SM on interface %s\n",
+				ifp->name);
 			return CMD_WARNING_CONFIG_FAILED;
 		}
 	}
@@ -9145,8 +9168,10 @@ DEFUN (ip_pim_bfd,
 	struct bfd_info *bfd_info = NULL;
 
 	if (!pim_ifp) {
-		if (!pim_cmd_interface_add(ifp)) {
-			vty_out(vty, "Could not enable PIM SM on interface\n");
+		if (!pim_cmd_interface_add(vty, ifp)) {
+			vty_out(vty,
+				"Could not enable PIM SM on interface %s\n",
+				ifp->name);
 			return CMD_WARNING;
 		}
 	}
@@ -9196,8 +9221,10 @@ DEFUN (ip_pim_bsm,
 	struct pim_interface *pim_ifp = ifp->info;
 
 	if (!pim_ifp) {
-		if (!pim_cmd_interface_add(ifp)) {
-			vty_out(vty, "Could not enable PIM SM on interface\n");
+		if (!pim_cmd_interface_add(vty, ifp)) {
+			vty_out(vty,
+				"Could not enable PIM SM on interface %s\n",
+				ifp->name);
 			return CMD_WARNING;
 		}
 	}
@@ -9240,8 +9267,10 @@ DEFUN (ip_pim_ucast_bsm,
 	struct pim_interface *pim_ifp = ifp->info;
 
 	if (!pim_ifp) {
-		if (!pim_cmd_interface_add(ifp)) {
-			vty_out(vty, "Could not enable PIM SM on interface\n");
+		if (!pim_cmd_interface_add(vty, ifp)) {
+			vty_out(vty,
+				"Could not enable PIM SM on interface %s\n",
+				ifp->name);
 			return CMD_WARNING;
 		}
 	}
@@ -9308,8 +9337,10 @@ DEFUN(
 	struct pim_interface *pim_ifp = ifp->info;
 
 	if (!pim_ifp) {
-		if (!pim_cmd_interface_add(ifp)) {
-			vty_out(vty, "Could not enable PIM SM on interface\n");
+		if (!pim_cmd_interface_add(vty, ifp)) {
+			vty_out(vty,
+				"Could not enable PIM SM on interface %s\n",
+				ifp->name);
 			return CMD_WARNING;
 		}
 	}