Re: iproute2/tc invalid JSON in v6.0.0-42-g49c63bc7 for "tc filter"

[Cong Wang <xiyou.wangcong@gmail.com>]

On Wed, Nov 16, 2022 at 05:46:09PM +0000, Christian Pössinger wrote:
> Dear Maintainers,
> 
> using revision v6.0.0-42-g49c63bc7 I noticed an invalid JSON output when invoking tc -json filter.
> 
> To reproduce the issue:
> 
> $ tc qdisc add dev eth1 handle ffff: ingress
> $ tc filter add dev eth1 parent ffff: prio 20 protocol all u32 match ip dport 22 \
>     0xffff action police conform-exceed drop/ok rate 100000 burst 15k flowid ffff:1
> 
> $ tc filter add dev eth1 parent ffff: prio 255 protocol all basic action police \
>     conform-exceed drop/ok rate 100000 burst 15k flowid ffff:3
> 
> 
> $ tc -detail -json filter show dev eth1 ingress
> [{"parent":"ffff:","protocol":"all","pref":20,"kind":"u32","chain":0},{"parent":"ffff:","protocol":"all","pref":20,"kind":"u32","chain":0,
> "options":{"fh":"800:","ht_divisor":1}},{"parent":"ffff:","protocol":"all","pref":20,"kind":"u32","chain":0,"options":{"fh":"800::800",
> "order":2048,"key_ht":"800","bkt":"0","flowid":"ffff:1","not_in_hw":true,"match":{"value":"16","mask":"ffff","offmask":"","off":20},
> "actions":[{"order":1,"kind":"police","index":1,"control_action":{"type":"drop"},"overhead":0,"linklayer":"ethernet","ref":1,"bind":1}]}},
> {"parent":"ffff:","protocol":"all","pref":255,"kind":"basic","chain":0},{"parent":"ffff:","protocol":"all","pref":255,"kind":"basic","chain":0,
> "options":{handle 0x1 flowid ffff:3 "actions":[{"order":1,"kind":"police","index":2,"control_action":{"type":"drop"},"overhead":0,"linklayer":"ethernet","ref":1,"bind":1}]}}]
> 
> 
> >>> json.loads(tmp)
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "/usr/lib/python3.9/json/__init__.py", line 346, in loads
>     return _default_decoder.decode(s)
>   File "/usr/lib/python3.9/json/decoder.py", line 337, in decode
>     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
>   File "/usr/lib/python3.9/json/decoder.py", line 353, in raw_decode
>     obj, end = self.scan_once(s, idx)
> json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 698 (char 697)
> 
> This actually contains invalid JSON here
> 
> ... "options":{handle 0x1 flowid ffff:3 "actions":[{"order" ...
> 
> It should actually read:
> 
> ... "options":{"handle":"0x1","flowid":"ffff:3","actions":[{"order" ...
> 
> If you can point me to the location which could be responsible for this issue, I am happy to submit a fix to the net tree.

Please take a look at tc/f_basic.c, I don't see it supports JSON as it
still uses fprintf() to print those fields. It should be converted to
print_hex() etc..

Thanks.