From: Donald Sharp <sharpd@nvidia.com>
Date: Tue, 4 Oct 2022 12:51:38 +0000 (-0400)
Subject: zebra: Allow tunneldump data to work properly on non-supported kernels
X-Git-Tag: frr-8.4~27^2
X-Git-Url: https://git.puffer.fish/?a=commitdiff_plain;h=refs%2Fpull%2F12067%2Fhead;p=mirror%2Ffrr.git

zebra: Allow tunneldump data to work properly on non-supported kernels

When zebra requests tunnel data it is sending a RTM_GETTUNNEL per
interface that is a VXLAN tunnel.  If the kernel that is being
used does not support the particular request type then zebra
will get a error message per tunnel request back.  Unfortunately
netlink_parse_info *stops* reading on the first error message.
Therefor one kernels that are returning an error message
let's gather all of those errors.  This will allow things
like route reads to actually work properly

Fixes: #12056
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit 451165eb57cd12795d8260ef927ce3d5ee4af9ed)
---

diff --git a/zebra/if_netlink.c b/zebra/if_netlink.c
index 0927bdc1d9..b28c468a96 100644
--- a/zebra/if_netlink.c
+++ b/zebra/if_netlink.c
@@ -1182,13 +1182,19 @@ int interface_lookup_netlink(struct zebra_ns *zns)
 	if (ret < 0)
 		return ret;
 
+	/*
+	 * So netlink_tunneldump_read will initiate a request
+	 * per tunnel to get data.  If we are on a kernel that
+	 * does not support this then we will get X error messages
+	 * (one per tunnel request )back which netlink_parse_info will
+	 * stop after the first one.  So we need to read equivalent
+	 * error messages per tunnel then we can continue.
+	 * if we do not gather all the read failures then
+	 * later requests will not work right.
+	 */
 	ret = netlink_tunneldump_read(zns);
 	if (ret < 0)
 		return ret;
-	ret = netlink_parse_info(netlink_interface, netlink_cmd, &dp_info, 0,
-				 true);
-	if (ret < 0)
-		return ret;
 
 	/* fixup linkages */
 	zebra_if_update_all_links(zns);
@@ -2322,6 +2328,7 @@ int netlink_tunneldump_read(struct zebra_ns *zns)
 	struct route_node *rn;
 	struct interface *tmp_if = NULL;
 	struct zebra_if *zif;
+	struct nlsock *netlink_cmd = &zns->netlink_cmd;
 
 	zebra_dplane_info_from_zns(&dp_info, zns, true /*is_cmd*/);
 
@@ -2337,7 +2344,14 @@ int netlink_tunneldump_read(struct zebra_ns *zns)
 						 tmp_if->ifindex);
 		if (ret < 0)
 			return ret;
+
+		ret = netlink_parse_info(netlink_interface, netlink_cmd,
+					 &dp_info, 0, true);
+
+		if (ret < 0)
+			return ret;
 	}
+
 	return 0;
 }
 #endif /* GNU_LINUX */