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

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

[Christian Pössinger]

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.

Thanks in advance,
Christian Poessinger

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

[Cong Wang]

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.

[PATCH iproute2] tc/basic: fix json output filter

[Stephen Hemminger]

The flowid and handle in basic were not using JSON routines to print.
 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

Reported-by: Christian Pössinger <christian@poessinger.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 tc/f_basic.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/tc/f_basic.c b/tc/f_basic.c
index 9a60758e803e..9055370e90b9 100644
--- a/tc/f_basic.c
+++ b/tc/f_basic.c
@@ -119,19 +119,22 @@ static int basic_print_opt(struct filter_util *qu, FILE *f,
 	parse_rtattr_nested(tb, TCA_BASIC_MAX, opt);
 
 	if (handle)
-		fprintf(f, "handle 0x%x ", handle);
+		print_hex(PRINT_ANY, "handle",
+			  "handle 0x%x ", handle);
 
 	if (tb[TCA_BASIC_CLASSID]) {
+		uint32_t classid = rta_getattr_u32(tb[TCA_BASIC_CLASSID]);
 		SPRINT_BUF(b1);
-		fprintf(f, "flowid %s ",
-			sprint_tc_classid(rta_getattr_u32(tb[TCA_BASIC_CLASSID]), b1));
+
+		print_string(PRINT_ANY, "flowid", "flowid %s ",
+			     sprint_tc_classid(classid, b1));
 	}
 
 	if (tb[TCA_BASIC_EMATCHES])
 		print_ematch(f, tb[TCA_BASIC_EMATCHES]);
 
 	if (tb[TCA_BASIC_POLICE]) {
-		fprintf(f, "\n");
+		print_nl();
 		tc_print_police(f, tb[TCA_BASIC_POLICE]);
 	}
 
-- 
2.35.1