When responding with NetKey List Status, packed NetKey indices into
3 octets per pair. If number of NetKeys is odd, append the last key
index as a 2-octet value.
---
mesh/net.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)
diff --git a/mesh/net.c b/mesh/net.c
index 0a4d2e72c..90ebdf496 100644
--- a/mesh/net.c
+++ b/mesh/net.c
@@ -1065,26 +1065,46 @@ bool mesh_net_get_key(struct mesh_net *net, bool new_key, uint16_t idx,
bool mesh_net_key_list_get(struct mesh_net *net, uint8_t *buf, uint16_t *size)
{
const struct l_queue_entry *entry;
- uint16_t n, buf_size;
+ uint16_t num_keys, req_size, buf_size;
+ struct mesh_subnet *subnet;
if (!net || !buf || !size)
return false;
buf_size = *size;
- if (buf_size < l_queue_length(net->subnets) * 2)
+
+ num_keys = l_queue_length(net->subnets);
+ req_size = (num_keys >> 1) * 3 + (num_keys % 2) * 2;
+
+ if (buf_size < req_size)
return false;
- n = 0;
- entry = l_queue_get_entries(net->subnets);
+ *size = req_size;
+
+ /* Pack NetKey indices in 3 octets */
+ for (entry = l_queue_get_entries(net->subnets); num_keys > 1;) {
+ uint32_t idx_pair;
- for (; entry; entry = entry->next) {
- struct mesh_subnet *subnet = entry->data;
+ subnet = entry->data;
+ idx_pair = subnet->idx;
+ idx_pair <<= 12;
+
+ subnet = entry->next->data;
+ idx_pair += subnet->idx;
+
+ l_put_le32(idx_pair, buf);
+ buf += 3;
+
+ num_keys -= 2;
+ entry = entry->next->next;
+ }
+ /* If odd number of NetKeys, fill in the end of the buffer */
+ if (num_keys % 2) {
+ subnet = entry->data;
l_put_le16(subnet->idx, buf);
- n += 2;
}
- *size = n;
return true;
}
--
2.21.1
Hi Inga,
On 01/09, Inga Stotland wrote:
> When responding with NetKey List Status, packed NetKey indices into
> 3 octets per pair. If number of NetKeys is odd, append the last key
> index as a 2-octet value.
> ---
> mesh/net.c | 36 ++++++++++++++++++++++++++++--------
> 1 file changed, 28 insertions(+), 8 deletions(-)
>
> diff --git a/mesh/net.c b/mesh/net.c
> index 0a4d2e72c..90ebdf496 100644
> --- a/mesh/net.c
> +++ b/mesh/net.c
> @@ -1065,26 +1065,46 @@ bool mesh_net_get_key(struct mesh_net *net, bool new_key, uint16_t idx,
> bool mesh_net_key_list_get(struct mesh_net *net, uint8_t *buf, uint16_t *size)
> {
> const struct l_queue_entry *entry;
> - uint16_t n, buf_size;
> + uint16_t num_keys, req_size, buf_size;
> + struct mesh_subnet *subnet;
>
> if (!net || !buf || !size)
> return false;
>
> buf_size = *size;
> - if (buf_size < l_queue_length(net->subnets) * 2)
> +
> + num_keys = l_queue_length(net->subnets);
> + req_size = (num_keys >> 1) * 3 + (num_keys % 2) * 2;
Please don't use bit shifts for division.
Also, I think it's clearer to write this as:
req_size = num_keys * 3 - num_keys % 2
> +
> + if (buf_size < req_size)
> return false;
>
> - n = 0;
> - entry = l_queue_get_entries(net->subnets);
> + *size = req_size;
> +
> + /* Pack NetKey indices in 3 octets */
> + for (entry = l_queue_get_entries(net->subnets); num_keys > 1;) {
> + uint32_t idx_pair;
>
> - for (; entry; entry = entry->next) {
> - struct mesh_subnet *subnet = entry->data;
> + subnet = entry->data;
> + idx_pair = subnet->idx;
> + idx_pair <<= 12;
> +
> + subnet = entry->next->data;
> + idx_pair += subnet->idx;
> +
> + l_put_le32(idx_pair, buf);
> + buf += 3;
> +
> + num_keys -= 2;
> + entry = entry->next->next;
> + }
>
> + /* If odd number of NetKeys, fill in the end of the buffer */
> + if (num_keys % 2) {
> + subnet = entry->data;
> l_put_le16(subnet->idx, buf);
> - n += 2;
> }
>
> - *size = n;
> return true;
> }
Tested-by: Michał Lowas-Rzechonek <[email protected]>
--
Michał Lowas-Rzechonek <[email protected]>
Silvair http://silvair.com
Jasnogórska 44, 31-358 Krakow, POLAND
Inga,
On 01/09, Inga Stotland wrote:
> When responding with NetKey List Status, packed NetKey indices into
> 3 octets per pair. If number of NetKeys is odd, append the last key
> index as a 2-octet value.
Another thing: doesn't this duplicate the same logic implemented in
appkey.c function appkey_list?
OP_APPKEY_LIST is (and was) working fine.
--
Michał Lowas-Rzechonek <[email protected]>
Silvair http://silvair.com
Jasnogórska 44, 31-358 Krakow, POLAND
Inga,
On 01/09, Stotland, Inga wrote:
>> Another thing: doesn't this duplicate the same logic implemented in
>> appkey.c function appkey_list?
>
> No, it's a different list organization. So I cannot re-use the code.
I understand that the list we iterate over is different, but in the end
the index list serialization format is exactly the same.
--
Michał Lowas-Rzechonek <[email protected]>
Silvair http://silvair.com
Jasnogórska 44, 31-358 Krakow, POLAND
Hi Michal,
On Thu, 2020-01-09 at 22:00 +0100, Michał Lowas-Rzechonek wrote:
> Hi Inga,
>
> On 01/09, Inga Stotland wrote:
> > When responding with NetKey List Status, packed NetKey indices into
> > 3 octets per pair. If number of NetKeys is odd, append the last key
> > index as a 2-octet value.
> > ---
> > mesh/net.c | 36 ++++++++++++++++++++++++++++--------
> > 1 file changed, 28 insertions(+), 8 deletions(-)
> >
> > diff --git a/mesh/net.c b/mesh/net.c
> > index 0a4d2e72c..90ebdf496 100644
> > --- a/mesh/net.c
> > +++ b/mesh/net.c
> > @@ -1065,26 +1065,46 @@ bool mesh_net_get_key(struct mesh_net *net,
> > bool new_key, uint16_t idx,
> > bool mesh_net_key_list_get(struct mesh_net *net, uint8_t *buf,
> > uint16_t *size)
> > {
> > const struct l_queue_entry *entry;
> > - uint16_t n, buf_size;
> > + uint16_t num_keys, req_size, buf_size;
> > + struct mesh_subnet *subnet;
> >
> > if (!net || !buf || !size)
> > return false;
> >
> > buf_size = *size;
> > - if (buf_size < l_queue_length(net->subnets) * 2)
> > +
> > + num_keys = l_queue_length(net->subnets);
> > + req_size = (num_keys >> 1) * 3 + (num_keys % 2) * 2;
>
> Please don't use bit shifts for division.
Why?
>
> Also, I think it's clearer to write this as:
> req_size = num_keys * 3 - num_keys % 2
>
This is not how I read the spec. We need to pack 2 key indices in 3
octets.
For example, 4 keys are packed in 6 octets and 5 keys are packed in 8
octets.
> > +
> > + if (buf_size < req_size)
> > return false;
> >
> > - n = 0;
> > - entry = l_queue_get_entries(net->subnets);
> > + *size = req_size;
> > +
> > + /* Pack NetKey indices in 3 octets */
> > + for (entry = l_queue_get_entries(net->subnets); num_keys > 1;)
> > {
> > + uint32_t idx_pair;
> >
> > - for (; entry; entry = entry->next) {
> > - struct mesh_subnet *subnet = entry->data;
> > + subnet = entry->data;
> > + idx_pair = subnet->idx;
> > + idx_pair <<= 12;
> > +
> > + subnet = entry->next->data;
> > + idx_pair += subnet->idx;
> > +
> > + l_put_le32(idx_pair, buf);
> > + buf += 3;
> > +
> > + num_keys -= 2;
> > + entry = entry->next->next;
> > + }
> >
> > + /* If odd number of NetKeys, fill in the end of the buffer */
> > + if (num_keys % 2) {
> > + subnet = entry->data;
> > l_put_le16(subnet->idx, buf);
> > - n += 2;
> > }
> >
> > - *size = n;
> > return true;
> > }
>
> Tested-by: Michał Lowas-Rzechonek <
> [email protected]
> >
>
>
On 01/09, Stotland, Inga wrote:
>> Please don't use bit shifts for division.
> Why?
Because it's a different operation, and is less readable. It's a
formula, so use math operators for numbers and bit operators for bits.
For example, idx_pair <<= 12 is fine, because the *context* is
bit-packing. Noone sane would write this as idx_pair *= 4096. This
reasoning applies the other way as well: don't write foo >> 2 where you
mean foo / 4.
>> Also, I think it's clearer to write this as:
>> req_size = num_keys * 3 - num_keys % 2
>
> No, this is not how I read the spec. We need to pack 2 key indices in 3 octets.
> For example, 4 keys are packed in 6 octets and 5 keys are packed in 8 octets.
Yes, you're right. Sorry.
--
Michał Lowas-Rzechonek <[email protected]>
Silvair http://silvair.com
Jasnogórska 44, 31-358 Krakow, POLAND
On Thu, 2020-01-09 at 22:29 +0100, [email protected]
wrote:
> On 01/09, Stotland, Inga wrote:
> > > Please don't use bit shifts for division.
> > Why?
>
> Because it's a different operation, and is less readable. It's a
> formula, so use math operators for numbers and bit operators for bits.
>
> For example, idx_pair <<= 12 is fine, because the *context* is
> bit-packing. Noone sane would write this as idx_pair *= 4096. This
> reasoning applies the other way as well: don't write foo >> 2 where you
> mean foo / 4.
Well, shift is a less expensive operation than a division (I believe,
some compilers may substitute integer division by 2 with a shift).
I don't see any reason not to use >> in this particular case, but I can
change if this is not readable...
>
> > > Also, I think it's clearer to write this as:
> > > req_size = num_keys * 3 - num_keys % 2
> >
> > No, this is not how I read the spec. We need to pack 2 key indices in 3 octets.
> > For example, 4 keys are packed in 6 octets and 5 keys are packed in 8 octets.
>
> Yes, you're right. Sorry.
>
On 01/09, Stotland, Inga wrote:
> Well, shift is a less expensive operation than a division (I believe,
> some compilers may substitute integer division by 2 with a shift).
So leave this to the compiler. In 99.999% cases it knows better.
http://www.linux-kongress.org/2009/slides/compiler_survey_felix_von_leitner.pdf slide 36
--
Michał Lowas-Rzechonek <[email protected]>
Silvair http://silvair.com
Jasnogórska 44, 31-358 Krakow, POLAND