On 17 May 2022, at 14:54, Jianbo Liu wrote:

> On Fri, 2022-05-13 at 16:55 +0200, Eelco Chaudron wrote:
>>
>>
>> On 3 May 2022, at 5:08, Jianbo Liu via dev wrote:
>>
>>> Add helpers to add, delete and get stats of police action with
>>> the specified index.
>>
>> See inline comments… This is the last patch for this week, I’ll
>> continue the review sometime next week!
>>
>>
>>> Signed-off-by: Jianbo Liu <[email protected]>
>>> ---
>>>  lib/netdev-linux.c | 133
>>> +++++++++++++++++++++++++++++++++++++++++++++
>>>  lib/netdev-linux.h |   6 ++
>>>  lib/tc.c           |  21 +++++++
>>>  lib/tc.h           |   6 ++
>>>  4 files changed, 166 insertions(+)
>>>
>>> diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
>>> index eb05153c0..ef6c7312f 100644
>>> --- a/lib/netdev-linux.c
>>> +++ b/lib/netdev-linux.c
>>> @@ -5664,6 +5664,139 @@ tc_add_policer(struct netdev *netdev,
>>> uint32_t kbits_rate,
>>>      return 0;
>>>  }
>>>
>>> +int
>>> +tc_add_policer_action(uint32_t index, uint32_t kbits_rate,
>>> +                      uint32_t kbits_burst, uint32_t pkts_rate,
>>> +                      uint32_t pkts_burst, bool update)
>>> +{
>>> +    struct tc_police tc_police;
>>> +    struct ofpbuf request;
>>> +    struct tcamsg *tcamsg;
>>> +    size_t offset;
>>> +    int flags;
>>> +
>>> +    tc_policer_init(&tc_police, kbits_rate, kbits_burst);
>>> +    tc_police.index = index;
>>> +
>>> +    flags = (update ? NLM_F_REPLACE : NLM_F_EXCL) | NLM_F_CREATE;
>>> +    tcamsg = tc_make_action_request(RTM_NEWACTION, flags,
>>> &request);
>>> +    if (!tcamsg) {
>>> +        return ENODEV;
>>> +    }
>>> +
>>> +    offset = nl_msg_start_nested(&request, TCA_ACT_TAB);
>>> +    nl_msg_put_act_police(&request, &tc_police, pkts_rate,
>>> pkts_burst);
>>> +    nl_msg_end_nested(&request, offset);
>>> +
>>> +    return tc_transact(&request, NULL);
>>> +}
>>> +
>>> +static int
>>> +tc_update_policer_action_stats(struct ofpbuf *msg,
>>> +                               struct ofputil_meter_stats *stats)
>>> +{
>>> +    const struct nlattr *act = NULL;
>>> +    struct tc_flower flower;
>>> +    struct nlattr *prio;
>>> +    struct tcamsg *tca;
>>> +    int error;
>>> +
>>
>> If would also do the if (!stats) return check here so none of the
>> APIs will crash if messed up.
>>
>>> +    if (NLMSG_HDRLEN + sizeof *tca > msg->size) {
>>> +        return EPROTO;
>>> +    }
>>> +
>>> +    tca = ofpbuf_at_assert(msg, NLMSG_HDRLEN, sizeof *tca);
>>> +
>>> +    act = nl_attr_find(msg, NLMSG_HDRLEN + sizeof *tca,
>>> TCA_ACT_TAB);
>>> +    if (!act) {
>>> +        return EPROTO;
>>> +    }
>>> +
>>> +    prio = (struct nlattr *) act + 1;
>>> +    memset(&flower, 0, sizeof(struct tc_flower));
>>> +    error = tc_parse_single_action(prio, &flower, false);
>>
>> I do not like this approach, we zero out a complex data structure
>> pass into a general function, and hope it gives us a counter we need.
>> I think we should separate out the statistics handling from
>> nl_parse_single_action() and make it available to use here.
>>
>>> +    if (!error) {
>>> +        stats->packet_in_count +=
>>> +            get_32aligned_u64(&flower.stats_sw.n_packets);
>>> +        stats->byte_in_count +=
>>> get_32aligned_u64(&flower.stats_sw.n_bytes);
>>> +        stats->packet_in_count +=
>>> +            get_32aligned_u64(&flower.stats_hw.n_packets);
>>> +        stats->byte_in_count +=
>>> get_32aligned_u64(&flower.stats_hw.n_bytes);
>>
>> What about the band stats on dropped packets? We need this to be in
>> line with the kernel dp.
>>
>
> It looks something wrong with tc police stats for the dropped packets,
> and someone is working on the kernel. Maybe we have to ignore this
> issue now?

I think this is very important for debugging. Maybe we can add the code to 
support this, so it will be there when it’s fixed in the kernel?

>>> +    }
>>> +
>>> +    return error;
>>> +}
>>> +
>>> +int
>>> +tc_get_policer_action(uint32_t index, struct ofputil_meter_stats
>>> *stats)
>>> +{
>>> +    struct ofpbuf *replyp = NULL;
>>> +    struct ofpbuf request;
>>> +    struct tcamsg *tcamsg;
>>> +    size_t root_offset;
>>> +    size_t prio_offset;
>>> +    int prio = 0;
>>> +    int error;
>>
>> If you do not add an “if !stats” check in
>> tc_update_policer_action_stats(), I would add it here to avoid
>> crashes with invalid API callback arguments.
>>
>>> +    tcamsg = tc_make_action_request(RTM_GETACTION, 0, &request);
>>> +    if (!tcamsg) {
>>> +        return ENODEV;
>>> +    }
>>> +
>>> +    root_offset = nl_msg_start_nested(&request, TCA_ACT_TAB);
>>> +    prio_offset = nl_msg_start_nested(&request, ++prio);
>>
>> Why do we need the ++prio variable? Can we just not call it with 1?
>>
>>> +    nl_msg_put_string(&request, TCA_ACT_KIND, "police");
>>> +    nl_msg_put_u32(&request, TCA_ACT_INDEX, index);
>>> +    nl_msg_end_nested(&request, prio_offset);
>>> +    nl_msg_end_nested(&request, root_offset);
>>> +
>>> +    error = tc_transact(&request, &replyp);
>>> +    if (error) {
>>> +        VLOG_ERR_RL(&rl, "failed to dump police action (index:
>>> %u), err=%d",
>>
>> Capital F for Failed.
>>
>>> +                    index, error);
>>> +        return error;
>>> +    }
>>> +
>>> +    error = tc_update_policer_action_stats(replyp, stats);
>>> +    if (error) {
>>> +        VLOG_ERR_RL(&rl, "failed to update police stats (index:
>>> %u), err=%d",
>>> +                    index, error);
>>
>> Capital F for Failed.
>>
>>
>> Any reason for having log messages here, but not for add and delete?
>>
>>> +    }
>>> +
>>> +    return error;
>>> +}
>>> +
>>> +int
>>> +tc_del_policer_action(uint32_t index, struct ofputil_meter_stats
>>> *stats)
>>> +{
>>> +    struct ofpbuf *replyp = NULL;
>>> +    struct ofpbuf request;
>>> +    struct tcamsg *tcamsg;
>>> +    size_t root_offset;
>>> +    size_t prio_offset;
>>> +    int prio = 0;
>>> +    int error;
>>> +
>>> +    tcamsg = tc_make_action_request(RTM_DELACTION, NLM_F_ACK,
>>> &request);
>>> +    if (!tcamsg) {
>>> +        return ENODEV;
>>> +    }
>>> +
>>> +    root_offset = nl_msg_start_nested(&request, TCA_ACT_TAB);
>>> +    prio_offset = nl_msg_start_nested(&request, ++prio);
>>
>> See above on prio.
>>
>>> +    nl_msg_put_string(&request, TCA_ACT_KIND, "police");
>>> +    nl_msg_put_u32(&request, TCA_ACT_INDEX, index);
>>> +    nl_msg_end_nested(&request, prio_offset);
>>> +    nl_msg_end_nested(&request, root_offset);
>>> +
>>> +    error = tc_transact(&request, &replyp);
>>> +    if (!error && stats) {
>>> +        error = tc_update_policer_action_stats(replyp, stats);
>>> +    }
>>         If the null check for stats get added to
>> tc_update_policer_action_stats() the code can be changed to:
>>
>>         if (error) {
>>             return error;
>>     }
>>         return tc_update_policer_action_stats(replyp, stats);
>>
>>> +
>>> +    return error;
>>> +}
>>> +
>>>  static void
>>>  read_psched(void)
>>>  {
>>> diff --git a/lib/netdev-linux.h b/lib/netdev-linux.h
>>> index e1e30f806..9a416ce50 100644
>>> --- a/lib/netdev-linux.h
>>> +++ b/lib/netdev-linux.h
>>> @@ -19,6 +19,7 @@
>>>
>>>  #include <stdint.h>
>>>  #include <stdbool.h>
>>> +#include "openvswitch/ofp-meter.h"
>>>
>>>  /* These functions are Linux specific, so they should be used
>>> directly only by
>>>   * Linux-specific code. */
>>> @@ -28,5 +29,10 @@ struct netdev;
>>>  int netdev_linux_ethtool_set_flag(struct netdev *netdev, uint32_t
>>> flag,
>>>                                    const char *flag_name, bool
>>> enable);
>>>  int linux_get_ifindex(const char *netdev_name);
>>> +int tc_add_policer_action(uint32_t index, uint32_t kbits_rate,
>>> +                          uint32_t kbits_burst, uint32_t
>>> pkts_rate,
>>> +                          uint32_t pkts_burst, bool update);
>>> +int tc_del_policer_action(uint32_t index, struct
>>> ofputil_meter_stats *stats);
>>> +int tc_get_policer_action(uint32_t index, struct
>>> ofputil_meter_stats *stats);
>>>
>>>  #endif /* netdev-linux.h */
>>> diff --git a/lib/tc.c b/lib/tc.c
>>> index af7a7bc6d..ee16364ea 100644
>>> --- a/lib/tc.c
>>> +++ b/lib/tc.c
>>> @@ -199,6 +199,20 @@ tc_make_request(int ifindex, int type,
>>> unsigned int flags,
>>>      return tcmsg;
>>>  }
>>>
>>> +struct tcamsg *
>>> +tc_make_action_request(int type, unsigned int flags,
>>> +                       struct ofpbuf *request)
>>> +{
>>> +    struct tcamsg *tcamsg;
>>> +
>>> +    ofpbuf_init(request, 512);
>>> +    nl_msg_put_nlmsghdr(request, sizeof *tcamsg, type,
>>> NLM_F_REQUEST | flags);
>>> +    tcamsg = ofpbuf_put_zeros(request, sizeof *tcamsg);
>>> +    tcamsg->tca_family = AF_UNSPEC;
>>> +
>>> +    return tcamsg;
>>> +}
>>> +
>>>  static void request_from_tcf_id(struct tcf_id *id, uint16_t
>>> eth_type,
>>>                                  int type, unsigned int flags,
>>>                                  struct ofpbuf *request)
>>> @@ -1863,6 +1877,13 @@ nl_parse_single_action(struct nlattr
>>> *action, struct tc_flower *flower,
>>>      return 0;
>>>  }
>>>
>>> +int
>>> +tc_parse_single_action(struct nlattr *action, struct tc_flower
>>> *flower,
>>> +                       bool terse)
>>> +{
>>> +    return nl_parse_single_action(action, flower, terse);
>>> +}
>>> +
>>
>> Why don’t we move all the functions in lib/netdev-linux.c above to
>> tc.c where they belong? I know it’s a bit more work, but it avoids
>> exposing internals like this.
>>
>
> It's because tc_add_policer_action() calls tc_policer_init() and
> nl_msg_put_act_police(), which uses much of code in netdev-linux.c.
> And there also is a similar func tc_action_policer() in this file.

I know it’s a mess right now, maybe you can do this as a follow-up patch, i.e. 
moving all TC to tc.c and only call a single function from this file to install 
the TC rule.

>>>  #define TCA_ACT_MIN_PRIO 1
>>>
>>>  static int
>>> diff --git a/lib/tc.h b/lib/tc.h
>>> index 201345672..96b9e6ccc 100644
>>> --- a/lib/tc.h
>>> +++ b/lib/tc.h
>>> @@ -80,6 +80,8 @@ tc_get_minor(unsigned int handle)
>>>
>>>  struct tcmsg *tc_make_request(int ifindex, int type,
>>>                                unsigned int flags, struct ofpbuf
>>> *);
>>> +struct tcamsg *tc_make_action_request(int type, unsigned int
>>> flags,
>>> +                                      struct ofpbuf *request);
>>>  int tc_transact(struct ofpbuf *request, struct ofpbuf **replyp);
>>>  int tc_add_del_qdisc(int ifindex, bool add, uint32_t block_id,
>>>                       enum tc_qdisc_hook hook);
>>> @@ -365,6 +367,8 @@ struct tc_flower {
>>>      enum tc_offload_policy tc_policy;
>>>  };
>>>
>>> +struct nlattr;
>>
>> Rather than this, would it make sense to include “netlink.h” at the
>> top? But this is not needed if we move the function to tc.c
>>
>>> +
>>>  int tc_replace_flower(struct tcf_id *id, struct tc_flower
>>> *flower);
>>>  int tc_del_filter(struct tcf_id *id);
>>>  int tc_get_flower(struct tcf_id *id, struct tc_flower *flower);
>>> @@ -376,5 +380,7 @@ int parse_netlink_to_tc_flower(struct ofpbuf
>>> *reply,
>>>                                 bool terse);
>>>  int parse_netlink_to_tc_chain(struct ofpbuf *reply, uint32_t
>>> *chain);
>>>  void tc_set_policy(const char *policy);
>>> +int tc_parse_single_action(struct nlattr *action, struct tc_flower
>>> *flower,
>>> +                           bool terse);
>>>
>>>  #endif /* tc.h */
>>> -- 
>>> 2.26.2
>>>
>>> _______________________________________________
>>> dev mailing list
>>> [email protected]
>>> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
>>

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