[PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[Roopa Prabhu]

From: Roopa Prabhu <roopa@cumulusnetworks.com>

This patch adds NLM_F_APPEND flag to struct nlmsg_hdr->nlmsg_flags
in newroute notifications if the route add was an append.
(This is similar to how NLM_F_REPLACE is already part of new
route replace notifications today)

This helps userspace determine if the route add operation was
an append.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
---
 net/ipv4/fib_trie.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 3c699c4..38ffc20 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1082,6 +1082,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 	struct trie *t = (struct trie *)tb->tb_data;
 	struct fib_alias *fa, *new_fa;
 	struct key_vector *l, *tp;
+	unsigned int nlflags = 0;
 	struct fib_info *fi;
 	u8 plen = cfg->fc_dst_len;
 	u8 slen = KEYLENGTH - plen;
@@ -1203,6 +1204,8 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 
 		if (!(cfg->fc_nlflags & NLM_F_APPEND))
 			fa = fa_first;
+		else
+			nlflags |= NLM_F_APPEND;
 	}
 	err = -ENOENT;
 	if (!(cfg->fc_nlflags & NLM_F_CREATE))
@@ -1238,7 +1241,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 
 	rt_cache_flush(cfg->fc_nlinfo.nl_net);
 	rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
-		  &cfg->fc_nlinfo, 0);
+		  &cfg->fc_nlinfo, nlflags);
 succeeded:
 	return 0;
 
-- 
1.7.10.4

Re: [PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[roopa]

On 6/16/15, 9:11 AM, Roopa Prabhu wrote:
> From: Roopa Prabhu <roopa@cumulusnetworks.com>
>
> This patch adds NLM_F_APPEND flag to struct nlmsg_hdr->nlmsg_flags
> in newroute notifications if the route add was an append.
> (This is similar to how NLM_F_REPLACE is already part of new
> route replace notifications today)
>
> This helps userspace determine if the route add operation was
> an append.
>
> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
please ignore, I plan to resend the patch against net-next

Re: [PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[Scott Feldman]

On Tue, Jun 16, 2015 at 9:11 AM, Roopa Prabhu <roopa@cumulusnetworks.com> wrote:

[snip]

> @@ -1203,6 +1204,8 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
>
>                 if (!(cfg->fc_nlflags & NLM_F_APPEND))
>                         fa = fa_first;
> +               else
> +                       nlflags |= NLM_F_APPEND;
>         }

The if and else parts above don't seem logically related.  Maybe you
could initialize nlflags as:

    unsigned int nlflags = cfg->fc_nlflags & (NLM_F_REPLACE|NLM_F_APPEND);

And then pass rtmsg_fib(..., nlflags) to avoid the flag test/set?

Re: [PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[roopa]

On 6/17/15, 12:50 AM, Scott Feldman wrote:
> On Tue, Jun 16, 2015 at 9:11 AM, Roopa Prabhu <roopa@cumulusnetworks.com> wrote:
>
> [snip]
>
>> @@ -1203,6 +1204,8 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
>>
>>                  if (!(cfg->fc_nlflags & NLM_F_APPEND))
>>                          fa = fa_first;
>> +               else
>> +                       nlflags |= NLM_F_APPEND;
>>          }
> The if and else parts above don't seem logically related.
I have it at this place because here is where the decision to append 
really happens.
>   Maybe you
> could initialize nlflags as:
>
>      unsigned int nlflags = cfg->fc_nlflags & (NLM_F_REPLACE|NLM_F_APPEND);
>
> And then pass rtmsg_fib(..., nlflags) to avoid the flag test/set?
nlflags should only contain NLM_F_REPLACE and NLM_F_APPEND if a replace or
append really took place. Hence the check and setting of nlflags is at 
the place where that
decision is made.

I had tried this patch a couple of other ways.... Do you think the below 
would be less confusing ?

thanks.



diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 3c699c4..9bfa3d8 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1082,6 +1082,7 @@ int fib_table_insert(struct fib_table *tb, struct 
fib_config *cfg)
         struct trie *t = (struct trie *)tb->tb_data;
         struct fib_alias *fa, *new_fa;
         struct key_vector *l, *tp;
+       unsigned int nlflags = 0;
         struct fib_info *fi;
         u8 plen = cfg->fc_dst_len;
         u8 slen = KEYLENGTH - plen;
@@ -1189,8 +1190,9 @@ int fib_table_insert(struct fib_table *tb, struct 
fib_config *cfg)
                         fib_release_info(fi_drop);
                         if (state & FA_S_ACCESSED)
rt_cache_flush(cfg->fc_nlinfo.nl_net);
+                       nlflags |= NLM_F_REPLACE;
                         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
-                               tb->tb_id, &cfg->fc_nlinfo, NLM_F_REPLACE);
+                               tb->tb_id, &cfg->fc_nlinfo, nlflags);

                         goto succeeded;
                 }
@@ -1201,7 +1203,9 @@ int fib_table_insert(struct fib_table *tb, struct 
fib_config *cfg)
                 if (fa_match)
                         goto out;

-               if (!(cfg->fc_nlflags & NLM_F_APPEND))
+               if (cfg->fc_nlflags & NLM_F_APPEND)
+                       nlflags |= NLM_F_APPEND;
+               else
                         fa = fa_first;
         }
         err = -ENOENT;
@@ -1238,7 +1242,7 @@ int fib_table_insert(struct fib_table *tb, struct 
fib_config *cfg)

         rt_cache_flush(cfg->fc_nlinfo.nl_net);
         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
-                 &cfg->fc_nlinfo, 0);
+                 &cfg->fc_nlinfo, nlflags);
  succeeded:
         return 0;

Re: [PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[Alexander Duyck]

On 06/17/2015 07:50 AM, roopa wrote:
> On 6/17/15, 12:50 AM, Scott Feldman wrote:
>> On Tue, Jun 16, 2015 at 9:11 AM, Roopa Prabhu
>> <roopa@cumulusnetworks.com> wrote:
>>
>> [snip]
>>
>>> @@ -1203,6 +1204,8 @@ int fib_table_insert(struct fib_table *tb,
>>> struct fib_config *cfg)
>>>
>>>                  if (!(cfg->fc_nlflags & NLM_F_APPEND))
>>>                          fa = fa_first;
>>> +               else
>>> +                       nlflags |= NLM_F_APPEND;
>>>          }
>> The if and else parts above don't seem logically related.
> I have it at this place because here is where the decision to append
> really happens.
>>   Maybe you
>> could initialize nlflags as:
>>
>>      unsigned int nlflags = cfg->fc_nlflags &
>> (NLM_F_REPLACE|NLM_F_APPEND);
>>
>> And then pass rtmsg_fib(..., nlflags) to avoid the flag test/set?
> nlflags should only contain NLM_F_REPLACE and NLM_F_APPEND if a replace or
> append really took place. Hence the check and setting of nlflags is at
> the place where that
> decision is made.
>
> I had tried this patch a couple of other ways.... Do you think the below
> would be less confusing ?
>
> thanks.
>
>
>
> diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
> index 3c699c4..9bfa3d8 100644
> --- a/net/ipv4/fib_trie.c
> +++ b/net/ipv4/fib_trie.c
> @@ -1082,6 +1082,7 @@ int fib_table_insert(struct fib_table *tb, struct
> fib_config *cfg)
>          struct trie *t = (struct trie *)tb->tb_data;
>          struct fib_alias *fa, *new_fa;
>          struct key_vector *l, *tp;
> +       unsigned int nlflags = 0;
>          struct fib_info *fi;
>          u8 plen = cfg->fc_dst_len;
>          u8 slen = KEYLENGTH - plen;
> @@ -1189,8 +1190,9 @@ int fib_table_insert(struct fib_table *tb, struct
> fib_config *cfg)
>                          fib_release_info(fi_drop);
>                          if (state & FA_S_ACCESSED)
> rt_cache_flush(cfg->fc_nlinfo.nl_net);
> +                       nlflags |= NLM_F_REPLACE;
>                          rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
> -                               tb->tb_id, &cfg->fc_nlinfo, NLM_F_REPLACE);
> +                               tb->tb_id, &cfg->fc_nlinfo, nlflags);
>
>                          goto succeeded;
>

Why even bother modifying this part?  Is this actually needed at all, 
are there some other flags you plan to drop into nlflags as well that 
would be passed as a part of this message?

> @@ -1201,7 +1203,9 @@ int fib_table_insert(struct fib_table *tb, struct
> fib_config *cfg)
>                  if (fa_match)
>                          goto out;
>
> -               if (!(cfg->fc_nlflags & NLM_F_APPEND))
> +               if (cfg->fc_nlflags & NLM_F_APPEND)
> +                       nlflags |= NLM_F_APPEND;
> +               else
>                          fa = fa_first;
>          }
>          err = -ENOENT;

I'm not sure I see the point of using the |=.   Why not just use a = and 
save yourself an instruction or two since you don't really need the OR 
operator in this case.

> @@ -1238,7 +1242,7 @@ int fib_table_insert(struct fib_table *tb, struct
> fib_config *cfg)
>
>          rt_cache_flush(cfg->fc_nlinfo.nl_net);
>          rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
> -                 &cfg->fc_nlinfo, 0);
> +                 &cfg->fc_nlinfo, nlflags);
>   succeeded:
>          return 0;
>
>

Re: [PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[roopa]

On 6/17/15, 8:35 AM, Alexander Duyck wrote:
>
>> @@ -1189,8 +1190,9 @@ int fib_table_insert(struct fib_table *tb, struct
>> fib_config *cfg)
>>                          fib_release_info(fi_drop);
>>                          if (state & FA_S_ACCESSED)
>> rt_cache_flush(cfg->fc_nlinfo.nl_net);
>> +                       nlflags |= NLM_F_REPLACE;
>>                          rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, 
>> plen,
>> -                               tb->tb_id, &cfg->fc_nlinfo, 
>> NLM_F_REPLACE);
>> +                               tb->tb_id, &cfg->fc_nlinfo, nlflags);
>>
>>                          goto succeeded;
>>
>
> Why even bother modifying this part?  Is this actually needed at all, 
> are there some other flags you plan to drop into nlflags as well that 
> would be passed as a part of this message?

agreed, for the same reason my initial patch did not touch this part. 
Nope, no other flags. I was trying to meet scotts concerns.
>
>> @@ -1201,7 +1203,9 @@ int fib_table_insert(struct fib_table *tb, struct
>> fib_config *cfg)
>>                  if (fa_match)
>>                          goto out;
>>
>> -               if (!(cfg->fc_nlflags & NLM_F_APPEND))
>> +               if (cfg->fc_nlflags & NLM_F_APPEND)
>> +                       nlflags |= NLM_F_APPEND;
>> +               else
>>                          fa = fa_first;
>>          }
>>          err = -ENOENT;
>
> I'm not sure I see the point of using the |=.   Why not just use a = 
> and save yourself an instruction or two since you don't really need 
> the OR operator in this case.
>
ack,

I would prefer keeping my initial patch which was pretty non-intrusive.

thanks,
Roopa

Re: [PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[Alexander Duyck]

On 06/17/2015 09:20 AM, roopa wrote:
> On 6/17/15, 8:35 AM, Alexander Duyck wrote:
>>
>>> @@ -1189,8 +1190,9 @@ int fib_table_insert(struct fib_table *tb, struct
>>> fib_config *cfg)
>>>                          fib_release_info(fi_drop);
>>>                          if (state & FA_S_ACCESSED)
>>> rt_cache_flush(cfg->fc_nlinfo.nl_net);
>>> +                       nlflags |= NLM_F_REPLACE;
>>>                          rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, 
>>> plen,
>>> -                               tb->tb_id, &cfg->fc_nlinfo, 
>>> NLM_F_REPLACE);
>>> +                               tb->tb_id, &cfg->fc_nlinfo, nlflags);
>>>
>>>                          goto succeeded;
>>>
>>
>> Why even bother modifying this part?  Is this actually needed at all, 
>> are there some other flags you plan to drop into nlflags as well that 
>> would be passed as a part of this message?
>
> agreed, for the same reason my initial patch did not touch this part. 
> Nope, no other flags. I was trying to meet scotts concerns.
>>
>>> @@ -1201,7 +1203,9 @@ int fib_table_insert(struct fib_table *tb, struct
>>> fib_config *cfg)
>>>                  if (fa_match)
>>>                          goto out;
>>>
>>> -               if (!(cfg->fc_nlflags & NLM_F_APPEND))
>>> +               if (cfg->fc_nlflags & NLM_F_APPEND)
>>> +                       nlflags |= NLM_F_APPEND;
>>> +               else
>>>                          fa = fa_first;
>>>          }
>>>          err = -ENOENT;
>>
>> I'm not sure I see the point of using the |=.   Why not just use a = 
>> and save yourself an instruction or two since you don't really need 
>> the OR operator in this case.
>>
> ack,
>
> I would prefer keeping my initial patch which was pretty non-intrusive.

I'd say go with something closer to the original patch, but flip the 
logic like you have here, and lose the "|=" in favor of an "=" since you 
are either sending a message with 0 or NLM_F_APPEND.

Anyway that is just my $.02.

- Alex

Re: [PATCH net] ipv4: include NLM_F_APPEND flag in append route notifications

[roopa]

On 6/17/15, 10:31 AM, Alexander Duyck wrote:
>
> I'd say go with something closer to the original patch, but flip the 
> logic like you have here, and lose the "|=" in favor of an "=" since 
> you are either sending a message with 0 or NLM_F_APPEND.
>
> Anyway that is just my $.02.
agreed,

thanks alex, v2 posted..