From 1d3e071fd8311aaea2f6c096ae117f39aff795ed Mon Sep 17 00:00:00 2001
From: Philippe Guibert <philippe.guibert@6wind.com>
Date: Wed, 15 Apr 2020 15:16:11 +0200
Subject: [PATCH] zebra: fix speed set to UINT32_MAX

get_iflink_speed() returns UINT32_MAX when the speeds is unknown.
Routing daemons (at least ospfd) interprets it as the high value.

Return errors in get_iflink_speed() to avoid the confusion.

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
---
 zebra/if_netlink.c | 13 ++++++++++---
 zebra/interface.c  |  6 +++---
 zebra/interface.h  |  3 +++
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/zebra/if_netlink.c b/zebra/if_netlink.c
index 551ef6533ed5..5f096e3039b1 100644
--- a/zebra/if_netlink.c
+++ b/zebra/if_netlink.c
@@ -261,6 +261,7 @@ static uint32_t get_iflink_speed(struct interface *interface, int *error)
 	int sd;
 	int rc;
 	const char *ifname = interface->name;
+	uint32_t ret;
 
 	if (error)
 		*error = 0;
@@ -285,7 +286,7 @@ static uint32_t get_iflink_speed(struct interface *interface, int *error)
 					   ifname, errno, safe_strerror(errno));
 			/* no vrf socket creation may probably mean vrf issue */
 			if (error)
-				*error = -1;
+				*error = INTERFACE_SPEED_ERROR_READ;
 			return 0;
 		}
 		/* Get the current link state for the interface */
@@ -299,14 +300,20 @@ static uint32_t get_iflink_speed(struct interface *interface, int *error)
 				ifname, errno, safe_strerror(errno));
 		/* no device means interface unreachable */
 		if (errno == ENODEV && error)
-			*error = -1;
+			*error = INTERFACE_SPEED_ERROR_READ;
 		ecmd.speed_hi = 0;
 		ecmd.speed = 0;
 	}
 
 	close(sd);
 
-	return ((uint32_t)ecmd.speed_hi << 16) | ecmd.speed;
+	ret = ((uint32_t)ecmd.speed_hi << 16) | ecmd.speed;
+	if (ret == UINT32_MAX) {
+		if (error)
+			*error = INTERFACE_SPEED_ERROR_UNKNOWN;
+		ret = 0;
+	}
+	return ret;
 }
 
 uint32_t kernel_get_speed(struct interface *ifp, int *error)
diff --git a/zebra/interface.c b/zebra/interface.c
index f864b9182253..4cb85152beb6 100644
--- a/zebra/interface.c
+++ b/zebra/interface.c
@@ -65,7 +65,7 @@ static void if_zebra_speed_update(struct event *thread)
 	 * interfaces not available.
 	 * note that loopback & virtual interfaces can return 0 as speed
 	 */
-	if (error < 0)
+	if (error == INTERFACE_SPEED_ERROR_READ)
 		return;
 
 	if (new_speed != ifp->speed) {
@@ -76,7 +76,7 @@ static void if_zebra_speed_update(struct event *thread)
 		changed = true;
 	}
 
-	if (changed || new_speed == UINT32_MAX) {
+	if (changed || error == INTERFACE_SPEED_ERROR_UNKNOWN) {
 #define SPEED_UPDATE_SLEEP_TIME 5
 #define SPEED_UPDATE_COUNT_MAX (4 * 60 / SPEED_UPDATE_SLEEP_TIME)
 		/*
@@ -91,7 +91,7 @@ static void if_zebra_speed_update(struct event *thread)
 		 * to not update the system to keep track of that.  This
 		 * is far simpler to just stop trying after 4 minutes
 		 */
-		if (new_speed == UINT32_MAX &&
+		if (error == INTERFACE_SPEED_ERROR_UNKNOWN &&
 		    zif->speed_update_count == SPEED_UPDATE_COUNT_MAX)
 			return;
 
diff --git a/zebra/interface.h b/zebra/interface.h
index a96f2ec7188d..15622652ccd3 100644
--- a/zebra/interface.h
+++ b/zebra/interface.h
@@ -201,6 +201,9 @@ struct zebra_if {
 	ifindex_t link_ifindex;
 	struct interface *link;
 
+#define INTERFACE_SPEED_ERROR_READ    -1
+#define INTERFACE_SPEED_ERROR_UNKNOWN -2
+
 	uint8_t speed_update_count;
 	struct event *speed_update;