Re: [PATCH 3/4 -rev1] Initilize and populate age field

[Varun Chandramohan <varunc@linux.vnet.ibm.com>]

Eric Dumazet wrote:
> Varun Chandramohan a écrit :
>> The age field is filled with the current time at the time of creation
>> of the route. When the routes are dumped
>> then the age value stored in the route structure is subtracted from
>> the current time value and the difference is the age expressed in secs.
>>
>> Signed-off-by: Varun Chandramohan <varunc@linux.vnet.ibm.com>
>> ---
>>  net/ipv4/fib_hash.c      |    3 +++
>>  net/ipv4/fib_lookup.h    |    3 ++-
>>  net/ipv4/fib_semantics.c |   16 +++++++++++++---
>>  net/ipv4/fib_trie.c      |    1 +
>>  4 files changed, 19 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c
>> index 07e843a..faa7364 100644
>> --- a/net/ipv4/fib_hash.c
>> +++ b/net/ipv4/fib_hash.c
>> @@ -448,6 +448,7 @@ static int fn_hash_insert(struct fib_tab
>>              fa->fa_info = fi;
>>              fa->fa_type = cfg->fc_type;
>>              fa->fa_scope = cfg->fc_scope;
>> +            fa->fa_age = 0;
>>              state = fa->fa_state;
>>              fa->fa_state &= ~FA_S_ACCESSED;
>>              fib_hash_genid++;
>> @@ -507,6 +508,7 @@ static int fn_hash_insert(struct fib_tab
>>      new_fa->fa_type = cfg->fc_type;
>>      new_fa->fa_scope = cfg->fc_scope;
>>      new_fa->fa_state = 0;
>> +    new_fa->fa_age = 0;
>>  
>>      /*
>>       * Insert new entry to the list.
>> @@ -697,6 +699,7 @@ fn_hash_dump_bucket(struct sk_buff *skb,
>>                        f->fn_key,
>>                        fz->fz_order,
>>                        fa->fa_tos,
>> +                      &fa->fa_age,
>>                        fa->fa_info,
>>                        NLM_F_MULTI) < 0) {
>>                  cb->args[4] = i;
>> diff --git a/net/ipv4/fib_lookup.h b/net/ipv4/fib_lookup.h
>> index eef9eec..c9145b5 100644
>> --- a/net/ipv4/fib_lookup.h
>> +++ b/net/ipv4/fib_lookup.h
>> @@ -13,6 +13,7 @@ struct fib_alias {
>>      u8            fa_type;
>>      u8            fa_scope;
>>      u8            fa_state;
>> +    time_t            fa_age;
>>  };
>>  
>>  #define FA_S_ACCESSED    0x01
>> @@ -27,7 +28,7 @@ extern struct fib_info *fib_create_info(
>>  extern int fib_nh_match(struct fib_config *cfg, struct fib_info *fi);
>>  extern int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int
>> event,
>>               u32 tb_id, u8 type, u8 scope, __be32 dst,
>> -             int dst_len, u8 tos, struct fib_info *fi,
>> +             int dst_len, u8 tos, time_t *age, struct fib_info *fi,
>>               unsigned int);
>>  extern void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
>>                int dst_len, u32 tb_id, struct nl_info *info,
>> diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
>> index c434119..1822d92 100644
>> --- a/net/ipv4/fib_semantics.c
>> +++ b/net/ipv4/fib_semantics.c
>> @@ -278,7 +278,8 @@ static inline size_t fib_nlmsg_size(stru
>>               + nla_total_size(4) /* RTA_TABLE */
>>               + nla_total_size(4) /* RTA_DST */
>>               + nla_total_size(4) /* RTA_PRIORITY */
>> -             + nla_total_size(4); /* RTA_PREFSRC */
>> +             + nla_total_size(4) /* RTA_PREFSRC */
>> +             + nla_total_size(4); /*RTA_AGE*/
>
> Not clear to me what happens on platforms where sizeof(time_t) is 8
>
I was aware of this issue, but the reason we decided to go with 4 is
that netlink is defined for use across a network. Since the size of
time_t varies in different architecture, it would mean that a system
with size 4 may not be able to talk to system with size 8. So i made it
constant. So in the above case we round off to 4.
>
>>  
>>      /* space for nested metrics */
>>      payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
>> @@ -313,7 +314,7 @@ void rtmsg_fib(int event, __be32 key, st
>>  
>>      err = fib_dump_info(skb, info->pid, seq, event, tb_id,
>>                  fa->fa_type, fa->fa_scope, key, dst_len,
>> -                fa->fa_tos, fa->fa_info, nlm_flags);
>> +                fa->fa_tos, &fa->fa_age, fa->fa_info, nlm_flags);
>>      if (err < 0) {
>>          /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
>>          WARN_ON(err == -EMSGSIZE);
>> @@ -940,11 +941,12 @@ __be32 __fib_res_prefsrc(struct fib_resu
>>  }
>>  
>>  int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
>> -          u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8
>> tos,
>> +          u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8
>> tos, time_t *age,
>>            struct fib_info *fi, unsigned int flags)
>>  {
>>      struct nlmsghdr *nlh;
>>      struct rtmsg *rtm;
>> +    struct timeval tv;
>>  
>>      nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
>>      if (nlh == NULL)
>> @@ -985,6 +987,14 @@ int fib_dump_info(struct sk_buff *skb, u
>>              NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
>>  #endif
>>      }
>> +
>> +    do_gettimeofday(&tv);
>> +    if (!*age) {
>> +        *age = timeval_to_sec(&tv);
>> +        NLA_PUT_U32(skb, RTA_AGE, *age);
>
> here, what happens if sizeof(time_t) is not 4 ?
>
Same case as above :-) comments?
>> +    } else {
>> +        NLA_PUT_U32(skb, RTA_AGE, timeval_to_sec(&tv) - *age);
>> +    }
>>  #ifdef CONFIG_IP_ROUTE_MULTIPATH
>>      if (fi->fib_nhs > 1) {
>>          struct rtnexthop *rtnh;
>> diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
>> index 30e332a..be2d1d6 100644
>> --- a/net/ipv4/fib_trie.c
>> +++ b/net/ipv4/fib_trie.c
>> @@ -1884,6 +1884,7 @@ static int fn_trie_dump_fa(t_key key, in
>>                    xkey,
>>                    plen,
>>                    fa->fa_tos,
>> +                  &fa->fa_age,
>>                    fa->fa_info, 0) < 0) {
>>              cb->args[4] = i;
>>              return -1;
>
> -
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