netdev - [PATCH] ip route: Do not imply pref and ttl-propagate are per nexthop

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Message-Id: <20200225131213.2709230-1-sharpd@cumulusnetworks.com>
Date:   Tue, 25 Feb 2020 08:12:13 -0500
From:   Donald Sharp <sharpd@...ulusnetworks.com>
To:     netdev@...r.kernel.org, dsahern@...nel.org,
        roopa@...ulusnetworks.com
Subject: [PATCH] ip route: Do not imply pref and ttl-propagate are per nexthop

Currently `ip -6 route show` gives us this output:

sharpd@eva ~/i/ip (master)> ip -6 route show
::1 dev lo proto kernel metric 256 pref medium
4:5::6:7 nhid 18 proto static metric 20
        nexthop via fe80::99 dev enp39s0 weight 1
        nexthop via fe80::44 dev enp39s0 weight 1 pref medium

Displaying `pref medium` as the last bit of output implies
that the RTA_PREF is a per nexthop value, when it is infact
a per route piece of data.

Change the output to display RTA_PREF and RTA_TTL_PROPAGATE
before the RTA_MULTIPATH data is shown:

sharpd@eva ~/i/ip (master)> ./ip -6 route show
::1 dev lo proto kernel metric 256 pref medium
4:5::6:7 nhid 18 proto static metric 20 pref medium
        nexthop via fe80::99 dev enp39s0 weight 1
        nexthop via fe80::44 dev enp39s0 weight 1

Signed-off-by: Donald Sharp <sharpd@...ulusnetworks.com>
---
 ip/iproute.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/ip/iproute.c b/ip/iproute.c
index 93b805c9..07c45169 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -933,9 +933,6 @@ int print_route(struct nlmsghdr *n, void *arg)
 	if (tb[RTA_IIF] && filter.iifmask != -1)
 		print_rta_if(fp, tb[RTA_IIF], "iif");
 
-	if (tb[RTA_MULTIPATH])
-		print_rta_multipath(fp, r, tb[RTA_MULTIPATH]);
-
 	if (tb[RTA_PREF])
 		print_rt_pref(fp, rta_getattr_u8(tb[RTA_PREF]));
 
@@ -951,6 +948,14 @@ int print_route(struct nlmsghdr *n, void *arg)
 				     propagate ? "enabled" : "disabled");
 	}
 
+	if (tb[RTA_MULTIPATH])
+		print_rta_multipath(fp, r, tb[RTA_MULTIPATH]);
+
+	/* If you are adding new route RTA_XXXX then place it above
+	 * the RTA_MULTIPATH else it will appear that the last nexthop
+	 * in the ECMP has new attributes
+	 */
+
 	print_string(PRINT_FP, NULL, "\n", NULL);
 	close_json_object();
 	fflush(fp);
-- 
2.25.0