[PATCH] iproute_lwtunnel: fix JSON output

[Stephen Hemminger <stephen@networkplumber.org>]

The same tag "dst" was being used for both the route destination
and the encap destination. This made it hard for JSON parsers.
Change to put the per-encap information under a nested JSON
object (similar to ip link type info).

Original output
[ {
        "dst": "192.168.11.0/24",
        "encap": "ip6",
        "id": 0,
        "src": "::",
        "dst": "fd00::c0a8:2dd",
        "hoplimit": 0,
        "tc": 0,
        "protocol": "5",
        "scope": "link",
        "flags": [ ]
    } ]

Revised output
[ {
        "dst": "192.168.11.0/24",
        "encap": {
            "encap_type": "ip6",
            "id": 0,
            "src": "::",
            "dst": "fd00::c0a8:2dd",
            "hoplimit": 0,
            "tc": 0
        },
        "protocol": "5",
        "scope": "link",
        "flags": [ ]
    } ]

Reported-by: Lars Ekman <uablrek@gmail.com>
Fixes: 663c3cb23103 ("iproute: implement JSON and color output")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 ip/iproute_lwtunnel.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/ip/iproute_lwtunnel.c b/ip/iproute_lwtunnel.c
index 8b7f3742b71e..9fcbdeac3e77 100644
--- a/ip/iproute_lwtunnel.c
+++ b/ip/iproute_lwtunnel.c
@@ -840,8 +840,9 @@ void lwt_print_encap(FILE *fp, struct rtattr *encap_type,
 		return;
 
 	et = rta_getattr_u16(encap_type);
-
-	print_string(PRINT_ANY, "encap", " encap %s ", format_encap_type(et));
+	open_json_object("encap");
+	print_string(PRINT_ANY, "encap_type", " encap %s ",
+		     format_encap_type(et));
 
 	switch (et) {
 	case LWTUNNEL_ENCAP_MPLS:
@@ -875,6 +876,7 @@ void lwt_print_encap(FILE *fp, struct rtattr *encap_type,
 		print_encap_xfrm(fp, encap);
 		break;
 	}
+	close_json_object();
 }
 
 static struct ipv6_sr_hdr *parse_srh(char *segbuf, int hmac, bool encap)
-- 
2.39.2