Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
On Tue, Sep 16, 2014 at 11:28:06AM +0100, Martin Townsend wrote:
>
> On 16/09/14 11:17, Alexander Aring wrote:
> > On Tue, Sep 16, 2014 at 11:04:13AM +0100, Martin Townsend wrote:
> >> Hi Alex,
> >>
> >> On the lowpan_give_skb_to_devices change.
> >>
> >> As we are iterating over a list of lowpan_devices and could potentially
> >> copy the skb more than once, what happens if the first device returns
> >> NET_RX_DROP and then the second time it return NET_RX_SUCCESS? The stat
> >> variable is overwritten so stat only ever reflects the return value of
> >> netif_rx for the last device?
> >>
> >> Maybe it's better to completely remove the if else at the end and always
> >> consume the skb? For the case whereskb_copy fails then we should
> >> kfree_skb,
> >> e.g.
> >>
> >> static int lowpan_give_skb_to_devices(struct sk_buff *skb,
> >> struct net_device *dev)
> >> {
> >>struct lowpan_dev_record *entry;
> >>struct sk_buff *skb_cp;
> >>int stat = NET_RX_SUCCESS;
> >>
> >>rcu_read_lock();
> >>list_for_each_entry_rcu(entry, &lowpan_devices, list)
> >>if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
> >>skb_cp = skb_copy(skb, GFP_ATOMIC);
> >>if (!skb_cp) {
> >>kfree_skb(skb);
> >>rcu_read_unlock();
> >>return NET_RX_DROP;
> >>}
> >>
> >>skb_cp->dev = entry->ldev;
> >>stat = netif_rx(skb_cp);
> > here we should do a:
> >
> > if (stat == NET_RX_DROP)
> > kfree_skb(skb_cp);
> >
> > or? It doesn't deliver and then we "could" lost the pointer.
> Doesn't netif_rx always free the buffer?
yes, you are right. [0] Now other things makes more sense for me.
Thanks.
I mean there is another deliver function netif_receive_skb and on
comment always stand "Return values (usually ignored)", depends on
context what you need. But netif_rx in this context is right.
Here we should not ignore the return value, because we already are in
the packet layer (the packet layer func callback). The netif_receive_skb
function we need for putting frames from the driver (some tasklet context)
into the packet layer.
[0] is some function which is called mainly after "netif_rx" function,
"netif_receive_skb" will call this function, too.
- Alex
[0] http://lxr.free-electrons.com/source/net/core/dev.c#L3280
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Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
On 16/09/14 11:17, Alexander Aring wrote:
> On Tue, Sep 16, 2014 at 11:04:13AM +0100, Martin Townsend wrote:
>> Hi Alex,
>>
>> On the lowpan_give_skb_to_devices change.
>>
>> As we are iterating over a list of lowpan_devices and could potentially copy
>> the skb more than once, what happens if the first device returns NET_RX_DROP
>> and then the second time it return NET_RX_SUCCESS? The stat variable is
>> overwritten so stat only ever reflects the return value of netif_rx for the
>> last device?
>>
>> Maybe it's better to completely remove the if else at the end and always
>> consume the skb? For the case whereskb_copy fails then we should kfree_skb,
>> e.g.
>>
>> static int lowpan_give_skb_to_devices(struct sk_buff *skb,
>>struct net_device *dev)
>> {
>> struct lowpan_dev_record *entry;
>> struct sk_buff *skb_cp;
>> int stat = NET_RX_SUCCESS;
>>
>> rcu_read_lock();
>> list_for_each_entry_rcu(entry, &lowpan_devices, list)
>> if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
>> skb_cp = skb_copy(skb, GFP_ATOMIC);
>> if (!skb_cp) {
>> kfree_skb(skb);
>> rcu_read_unlock();
>> return NET_RX_DROP;
>> }
>>
>> skb_cp->dev = entry->ldev;
>> stat = netif_rx(skb_cp);
> here we should do a:
>
> if (stat == NET_RX_DROP)
> kfree_skb(skb_cp);
>
> or? It doesn't deliver and then we "could" lost the pointer.
Doesn't netif_rx always free the buffer?
>> }
>> rcu_read_unlock();
>>
>> consume_skb(skb);
>>
>> return stat;
>> }
>>
>>
>> what are your thoughts?
>>
> for consume_skb:
>
> for me it's ok to make this behaviour. We never deliver the skb, always
> skb_cp. So if we are before the deliver call (netif_rx) this should
> never failed and we should consume the skb from which we did some copies.
yep
>
>
>
>
> btw.
>
> I see now that's skb_copy... mhhh. But this another issue. There exist
> skb_clone and skb_copy. skb_clone make a copy of struct sk_buff and data
> buffer is shared. I am currently not sure if we also can use a skb_clone
> here instead skb_copy, because the IPv6 doesn't manipulate the data buffer
> (I think it doesn't change the data buffer -> only parse) I need to think
> more about this, just a performance hint. But I really also doesn't know
> what sense makes multiple lowpan devices for one wpan interface. :-)
skb_clone could be a future patch.
Also I have been wondering why there are multiple lowpan device multiplexed
onto a wpan. Again maybe a future patch.
>
> - Alex
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- Martin.
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Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
On Tue, Sep 16, 2014 at 11:04:13AM +0100, Martin Townsend wrote:
> Hi Alex,
>
> On the lowpan_give_skb_to_devices change.
>
> As we are iterating over a list of lowpan_devices and could potentially copy
> the skb more than once, what happens if the first device returns NET_RX_DROP
> and then the second time it return NET_RX_SUCCESS? The stat variable is
> overwritten so stat only ever reflects the return value of netif_rx for the
> last device?
>
> Maybe it's better to completely remove the if else at the end and always
> consume the skb? For the case whereskb_copy fails then we should kfree_skb,
> e.g.
>
> static int lowpan_give_skb_to_devices(struct sk_buff *skb,
> struct net_device *dev)
> {
> struct lowpan_dev_record *entry;
> struct sk_buff *skb_cp;
> int stat = NET_RX_SUCCESS;
>
> rcu_read_lock();
> list_for_each_entry_rcu(entry, &lowpan_devices, list)
> if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
> skb_cp = skb_copy(skb, GFP_ATOMIC);
> if (!skb_cp) {
> kfree_skb(skb);
> rcu_read_unlock();
> return NET_RX_DROP;
> }
>
> skb_cp->dev = entry->ldev;
> stat = netif_rx(skb_cp);
here we should do a:
if (stat == NET_RX_DROP)
kfree_skb(skb_cp);
or? It doesn't deliver and then we "could" lost the pointer.
> }
> rcu_read_unlock();
>
> consume_skb(skb);
>
> return stat;
> }
>
>
> what are your thoughts?
>
for consume_skb:
for me it's ok to make this behaviour. We never deliver the skb, always
skb_cp. So if we are before the deliver call (netif_rx) this should
never failed and we should consume the skb from which we did some copies.
btw.
I see now that's skb_copy... mhhh. But this another issue. There exist
skb_clone and skb_copy. skb_clone make a copy of struct sk_buff and data
buffer is shared. I am currently not sure if we also can use a skb_clone
here instead skb_copy, because the IPv6 doesn't manipulate the data buffer
(I think it doesn't change the data buffer -> only parse) I need to think
more about this, just a performance hint. But I really also doesn't know
what sense makes multiple lowpan devices for one wpan interface. :-)
- Alex
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Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
Hi Alex,
On the lowpan_give_skb_to_devices change.
As we are iterating over a list of lowpan_devices and could potentially copy
the skb more than once, what happens if the first device returns NET_RX_DROP
and then the second time it return NET_RX_SUCCESS? The stat variable is
overwritten so stat only ever reflects the return value of netif_rx for the
last device?
Maybe it's better to completely remove the if else at the end and always
consume the skb? For the case whereskb_copy fails then we should kfree_skb,
e.g.
static int lowpan_give_skb_to_devices(struct sk_buff *skb,
struct net_device *dev)
{
struct lowpan_dev_record *entry;
struct sk_buff *skb_cp;
int stat = NET_RX_SUCCESS;
rcu_read_lock();
list_for_each_entry_rcu(entry, &lowpan_devices, list)
if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
skb_cp = skb_copy(skb, GFP_ATOMIC);
if (!skb_cp) {
kfree_skb(skb);
rcu_read_unlock();
return NET_RX_DROP;
}
skb_cp->dev = entry->ldev;
stat = netif_rx(skb_cp);
}
rcu_read_unlock();
consume_skb(skb);
return stat;
}
what are your thoughts?
-Martin.
On 16/09/14 07:57, Alexander Aring wrote:
>
> --- snap
>
> Ignore the below one, I will only note about this... that we don't
> forget that.
>
> This code should be a generic function for increasing headroom for
> decompressing headers (IPv6, next hdr's). Still issues with
> consume_skb/kfree_skb here.
>
>
> + if (stat < 0) {
> + kfree_skb(skb);
> + stat = NET_RX_DROP;
> + } else {
> + consume_skb(skb);
> + }
> This basically works now, but it confuse developers.
>
> Look how stat is initzialed.
> There is mixed errno and NET_RX_FOO handling here. Which is part of the
> complete error handling mess. And correct freeing of skb's required a
> correct error handling.
>
> The function looks now like this:
>
> struct lowpan_dev_record *entry;
> struct sk_buff *skb_cp;
> int stat = NET_RX_SUCCESS;
>
> rcu_read_lock();
> list_for_each_entry_rcu(entry, &lowpan_devices, list)
> if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
> skb_cp = skb_copy(skb, GFP_ATOMIC);
> if (!skb_cp) {
> stat = -ENOMEM;
> Simple assign stat = NET_RX_DROP.
> break;
> }
>
> skb_cp->dev = entry->ldev;
> stat = netif_rx(skb_cp);
> }
> rcu_read_unlock();
>
> if (stat < 0) {
> remove brackets and check on NET_RX_DROP. or vice versa.
> kfree_skb(skb);
> stat = NET_RX_DROP;
> } else {
> consume_skb(skb);
> }
> return stat;
>
> Now if the list is empty we check if (stat < 0) with a NET_RX_FOO stuff,
> we should avoid that. I mean the current situation is because somebody
> mixed this stuff and that's why we have this now.
>
> Another developers look of some code (that's what I did) and see, aaah
> returning NET_RX_FOO so we can check on it, but at this situation he
> need to think a little bit more what it is the correct handline because
> there is still some errno conversion.
>
>> return stat;
>> }
>>
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Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
On Tue, Sep 16, 2014 at 11:06:08AM +0200, Alexander Aring wrote: ... > > Are you saying that skb->len needs setting here? or just that to do on the > > fly decompression it's required? > > > and I was wrong here, I mean we need the IPv6 header payload need to set according "skb->len - sizeof(...ipv6hdr)". that's currently setted while uncompression, but for our use case with fragmentation while receiving FRAG1 skb->len is wrong. btw. I also detected right now that makes also trouble with next header compression payload size attributes. But this is a complete other issue. We need make this as next step when we insert next header framework. Otherwise we can't uncompress on the fly while receiving FRAG1, but we need to handle this in that way to remove the ugly workaround solution. Nobody says that this would be easy. - Alex -- Want excitement? Manually upgrade your production database. When you want reliability, choose Perforce. Perforce version control. Predictably reliable. http://pubads.g.doubleclick.net/gampad/clk?id=157508191&iu=/4140/ostg.clktrk ___ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
On Tue, Sep 16, 2014 at 09:28:10AM +0100, Martin Townsend wrote:
> Hi Alex,
>
> On 16/09/14 07:57, Alexander Aring wrote:
> > Hi Martin,
> >
> > On Mon, Sep 15, 2014 at 03:09:54PM +0100, Martin Townsend wrote:
> >> Currently there are a number of error paths in the lowpan_rcv function that
> >> free the skb before returning, the patch simplifies the receive path by
> >> ensuring that the skb is only freed from this function.
> >>
> >> Passing the skb from 6lowpan up to the higher layers is not a
> >> function of IPHC. By moving it out of IPHC we also remove the
> >> need to support error code returns with NET_RX codes.
> >> It also makes the lowpan_rcv function more extendable as we
> >> can support more compression schemes.
> >>
> >> With the above 2 lowpan_rcv is refacored so eliminate incorrect return
> >> values.
> >>
> >> Signed-off-by: Martin Townsend
> >> ---
> >> include/net/6lowpan.h | 4 +--
> >> net/6lowpan/iphc.c| 74
> >> ++-
> >> net/bluetooth/6lowpan.c | 26 +--
> >> net/ieee802154/6lowpan_rtnl.c | 55
> >> 4 files changed, 83 insertions(+), 76 deletions(-)
> >>
> >> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> >> index d184df1..450eaaf 100644
> >> --- a/include/net/6lowpan.h
> >> +++ b/include/net/6lowpan.h
> >> @@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb,
> >> u16 *dgram_offset)
> >>
> >> typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device
> >> *dev);
> >>
> >> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> >> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device
> >> *dev,
> >>const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
> >>const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
> >> - u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
> >> + u8 iphc0, u8 iphc1);
> >> int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
> >>unsigned short type, const void *_daddr,
> >>const void *_saddr, unsigned int len);
> >> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> >> index 142eef5..d51e8bb 100644
> >> --- a/net/6lowpan/iphc.c
> >> +++ b/net/6lowpan/iphc.c
> >> @@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct
> >> sk_buff *skb,
> >>return 0;
> >> }
> >>
> >> -static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
> >> - struct net_device *dev, skb_delivery_cb deliver_skb)
> >> -{
> >> - struct sk_buff *new;
> >> - int stat;
> >> -
> >> - new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
> >> -GFP_ATOMIC);
> >> - kfree_skb(skb);
> >> -
> >> - if (!new)
> >> - return -ENOMEM;
> >> -
> >> - skb_push(new, sizeof(struct ipv6hdr));
> >> - skb_reset_network_header(new);
> >> - skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
> >> -
> >> - new->protocol = htons(ETH_P_IPV6);
> >> - new->pkt_type = PACKET_HOST;
> >> - new->dev = dev;
> >> -
> >> - raw_dump_table(__func__, "raw skb data dump before receiving",
> >> - new->data, new->len);
> >> -
> >> - stat = deliver_skb(new, dev);
> >> -
> >> - kfree_skb(new);
> >> -
> >> - return stat;
> >> -}
> >> -
> >> /* Uncompress function for multicast destination address,
> >> * when M bit is set.
> >> */
> >> @@ -332,14 +301,15 @@ err:
> >> /* TTL uncompression values */
> >> static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
> >>
> >> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> >> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device
> >> *dev,
> >>const u8 *saddr, const u8 saddr_type, const u8
> >> saddr_len,
> >>const u8 *daddr, const u8 daddr_type, const u8
> >> daddr_len,
> >> - u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
> >> + u8 iphc0, u8 iphc1)
> >> {
> >>struct ipv6hdr hdr = {};
> >>u8 tmp, num_context = 0;
> >> - int err;
> >> + int err = -EINVAL;
> >> + struct sk_buff *skb = *skb_inout;
> >>
> >>raw_dump_table(__func__, "raw skb data dump uncompressed",
> >> skb->data, skb->len);
> >> @@ -460,7 +430,6 @@ int lowpan_process_data(struct sk_buff *skb, struct
> >> net_device *dev,
> >>/* UDP data uncompression */
> >>if (iphc0 & LOWPAN_IPHC_NH_C) {
> >>struct udphdr uh;
> >> - struct sk_buff *new;
> >>
> >>if (uncompress_udp_header(skb, &uh))
> >>goto drop;
> >> @@ -468,14 +437,15 @@ int lowpan_process_data(struct sk_buff *skb, struct
> >> net_device *dev,
> >>/* replace the compressed UDP head by the uncompressed UDP
> >> * header
> >> */
> >> - new = skb_copy_expand(skb, size
Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
Hi Jukka, On 16/09/14 08:04, Jukka Rissanen wrote: > Hi Martin, > > On ma, 2014-09-15 at 15:09 +0100, Martin Townsend wrote: >> Currently there are a number of error paths in the lowpan_rcv function that >> free the skb before returning, the patch simplifies the receive path by >> ensuring that the skb is only freed from this function. >> >> Passing the skb from 6lowpan up to the higher layers is not a >> function of IPHC. By moving it out of IPHC we also remove the >> need to support error code returns with NET_RX codes. >> It also makes the lowpan_rcv function more extendable as we >> can support more compression schemes. >> >> With the above 2 lowpan_rcv is refacored so eliminate incorrect return >> values. > I like the idea that we get rid of the callback function. > We could probably refactor the patch a bit further thou as the > lowpan_process_data() could return the skb directly instead of being > passed as a parameter. In the caller we could use the IS_ERR() macro to > check if the returned value is an error or a real pointer. > No probs, will respin v4 patch later. > Cheers, > Jukka > > - Martin. -- Want excitement? Manually upgrade your production database. When you want reliability, choose Perforce. Perforce version control. Predictably reliable. http://pubads.g.doubleclick.net/gampad/clk?id=157508191&iu=/4140/ostg.clktrk ___ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
Hi Alex,
On 16/09/14 07:57, Alexander Aring wrote:
> Hi Martin,
>
> On Mon, Sep 15, 2014 at 03:09:54PM +0100, Martin Townsend wrote:
>> Currently there are a number of error paths in the lowpan_rcv function that
>> free the skb before returning, the patch simplifies the receive path by
>> ensuring that the skb is only freed from this function.
>>
>> Passing the skb from 6lowpan up to the higher layers is not a
>> function of IPHC. By moving it out of IPHC we also remove the
>> need to support error code returns with NET_RX codes.
>> It also makes the lowpan_rcv function more extendable as we
>> can support more compression schemes.
>>
>> With the above 2 lowpan_rcv is refacored so eliminate incorrect return
>> values.
>>
>> Signed-off-by: Martin Townsend
>> ---
>> include/net/6lowpan.h | 4 +--
>> net/6lowpan/iphc.c| 74
>> ++-
>> net/bluetooth/6lowpan.c | 26 +--
>> net/ieee802154/6lowpan_rtnl.c | 55
>> 4 files changed, 83 insertions(+), 76 deletions(-)
>>
>> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
>> index d184df1..450eaaf 100644
>> --- a/include/net/6lowpan.h
>> +++ b/include/net/6lowpan.h
>> @@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16
>> *dgram_offset)
>>
>> typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
>>
>> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
>> const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
>> const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
>> -u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
>> +u8 iphc0, u8 iphc1);
>> int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
>> unsigned short type, const void *_daddr,
>> const void *_saddr, unsigned int len);
>> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
>> index 142eef5..d51e8bb 100644
>> --- a/net/6lowpan/iphc.c
>> +++ b/net/6lowpan/iphc.c
>> @@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct
>> sk_buff *skb,
>> return 0;
>> }
>>
>> -static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
>> - struct net_device *dev, skb_delivery_cb deliver_skb)
>> -{
>> -struct sk_buff *new;
>> -int stat;
>> -
>> -new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
>> - GFP_ATOMIC);
>> -kfree_skb(skb);
>> -
>> -if (!new)
>> -return -ENOMEM;
>> -
>> -skb_push(new, sizeof(struct ipv6hdr));
>> -skb_reset_network_header(new);
>> -skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
>> -
>> -new->protocol = htons(ETH_P_IPV6);
>> -new->pkt_type = PACKET_HOST;
>> -new->dev = dev;
>> -
>> -raw_dump_table(__func__, "raw skb data dump before receiving",
>> - new->data, new->len);
>> -
>> -stat = deliver_skb(new, dev);
>> -
>> -kfree_skb(new);
>> -
>> -return stat;
>> -}
>> -
>> /* Uncompress function for multicast destination address,
>> * when M bit is set.
>> */
>> @@ -332,14 +301,15 @@ err:
>> /* TTL uncompression values */
>> static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
>>
>> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
>> const u8 *saddr, const u8 saddr_type, const u8
>> saddr_len,
>> const u8 *daddr, const u8 daddr_type, const u8
>> daddr_len,
>> -u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
>> +u8 iphc0, u8 iphc1)
>> {
>> struct ipv6hdr hdr = {};
>> u8 tmp, num_context = 0;
>> -int err;
>> +int err = -EINVAL;
>> +struct sk_buff *skb = *skb_inout;
>>
>> raw_dump_table(__func__, "raw skb data dump uncompressed",
>> skb->data, skb->len);
>> @@ -460,7 +430,6 @@ int lowpan_process_data(struct sk_buff *skb, struct
>> net_device *dev,
>> /* UDP data uncompression */
>> if (iphc0 & LOWPAN_IPHC_NH_C) {
>> struct udphdr uh;
>> -struct sk_buff *new;
>>
>> if (uncompress_udp_header(skb, &uh))
>> goto drop;
>> @@ -468,14 +437,15 @@ int lowpan_process_data(struct sk_buff *skb, struct
>> net_device *dev,
>> /* replace the compressed UDP head by the uncompressed UDP
>> * header
>> */
>> -new = skb_copy_expand(skb, sizeof(struct udphdr),
>> +skb = skb_copy_expand(skb, sizeof(struct udphdr),
>>skb_tailroom(skb), GFP_ATOMIC);
>> -kfree_skb(skb);
>> -
>> -if (!new)
>> -
Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
On Tue, Sep 16, 2014 at 10:04:57AM +0300, Jukka Rissanen wrote: > Hi Martin, > > On ma, 2014-09-15 at 15:09 +0100, Martin Townsend wrote: > > Currently there are a number of error paths in the lowpan_rcv function that > > free the skb before returning, the patch simplifies the receive path by > > ensuring that the skb is only freed from this function. > > > > Passing the skb from 6lowpan up to the higher layers is not a > > function of IPHC. By moving it out of IPHC we also remove the > > need to support error code returns with NET_RX codes. > > It also makes the lowpan_rcv function more extendable as we > > can support more compression schemes. > > > > With the above 2 lowpan_rcv is refacored so eliminate incorrect return > > values. > > I like the idea that we get rid of the callback function. > > We could probably refactor the patch a bit further thou as the > lowpan_process_data() could return the skb directly instead of being > passed as a parameter. In the caller we could use the IS_ERR() macro to > check if the returned value is an error or a real pointer. > > ack, then we can also drop the **inout_skb thing. - Alex -- Want excitement? Manually upgrade your production database. When you want reliability, choose Perforce. Perforce version control. Predictably reliable. http://pubads.g.doubleclick.net/gampad/clk?id=157508191&iu=/4140/ostg.clktrk ___ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
Hi Martin, On ma, 2014-09-15 at 15:09 +0100, Martin Townsend wrote: > Currently there are a number of error paths in the lowpan_rcv function that > free the skb before returning, the patch simplifies the receive path by > ensuring that the skb is only freed from this function. > > Passing the skb from 6lowpan up to the higher layers is not a > function of IPHC. By moving it out of IPHC we also remove the > need to support error code returns with NET_RX codes. > It also makes the lowpan_rcv function more extendable as we > can support more compression schemes. > > With the above 2 lowpan_rcv is refacored so eliminate incorrect return values. I like the idea that we get rid of the callback function. We could probably refactor the patch a bit further thou as the lowpan_process_data() could return the skb directly instead of being passed as a parameter. In the caller we could use the IS_ERR() macro to check if the returned value is an error or a real pointer. Cheers, Jukka -- Want excitement? Manually upgrade your production database. When you want reliability, choose Perforce. Perforce version control. Predictably reliable. http://pubads.g.doubleclick.net/gampad/clk?id=157508191&iu=/4140/ostg.clktrk ___ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
Re: [Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
Hi Martin,
On Mon, Sep 15, 2014 at 03:09:54PM +0100, Martin Townsend wrote:
> Currently there are a number of error paths in the lowpan_rcv function that
> free the skb before returning, the patch simplifies the receive path by
> ensuring that the skb is only freed from this function.
>
> Passing the skb from 6lowpan up to the higher layers is not a
> function of IPHC. By moving it out of IPHC we also remove the
> need to support error code returns with NET_RX codes.
> It also makes the lowpan_rcv function more extendable as we
> can support more compression schemes.
>
> With the above 2 lowpan_rcv is refacored so eliminate incorrect return values.
>
> Signed-off-by: Martin Townsend
> ---
> include/net/6lowpan.h | 4 +--
> net/6lowpan/iphc.c| 74
> ++-
> net/bluetooth/6lowpan.c | 26 +--
> net/ieee802154/6lowpan_rtnl.c | 55
> 4 files changed, 83 insertions(+), 76 deletions(-)
>
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index d184df1..450eaaf 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16
> *dgram_offset)
>
> typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
>
> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
> const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
> const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
> - u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
> + u8 iphc0, u8 iphc1);
> int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
> unsigned short type, const void *_daddr,
> const void *_saddr, unsigned int len);
> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> index 142eef5..d51e8bb 100644
> --- a/net/6lowpan/iphc.c
> +++ b/net/6lowpan/iphc.c
> @@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct
> sk_buff *skb,
> return 0;
> }
>
> -static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
> -struct net_device *dev, skb_delivery_cb deliver_skb)
> -{
> - struct sk_buff *new;
> - int stat;
> -
> - new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
> - GFP_ATOMIC);
> - kfree_skb(skb);
> -
> - if (!new)
> - return -ENOMEM;
> -
> - skb_push(new, sizeof(struct ipv6hdr));
> - skb_reset_network_header(new);
> - skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
> -
> - new->protocol = htons(ETH_P_IPV6);
> - new->pkt_type = PACKET_HOST;
> - new->dev = dev;
> -
> - raw_dump_table(__func__, "raw skb data dump before receiving",
> -new->data, new->len);
> -
> - stat = deliver_skb(new, dev);
> -
> - kfree_skb(new);
> -
> - return stat;
> -}
> -
> /* Uncompress function for multicast destination address,
> * when M bit is set.
> */
> @@ -332,14 +301,15 @@ err:
> /* TTL uncompression values */
> static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
>
> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
> const u8 *saddr, const u8 saddr_type, const u8
> saddr_len,
> const u8 *daddr, const u8 daddr_type, const u8
> daddr_len,
> - u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
> + u8 iphc0, u8 iphc1)
> {
> struct ipv6hdr hdr = {};
> u8 tmp, num_context = 0;
> - int err;
> + int err = -EINVAL;
> + struct sk_buff *skb = *skb_inout;
>
> raw_dump_table(__func__, "raw skb data dump uncompressed",
> skb->data, skb->len);
> @@ -460,7 +430,6 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> /* UDP data uncompression */
> if (iphc0 & LOWPAN_IPHC_NH_C) {
> struct udphdr uh;
> - struct sk_buff *new;
>
> if (uncompress_udp_header(skb, &uh))
> goto drop;
> @@ -468,14 +437,15 @@ int lowpan_process_data(struct sk_buff *skb, struct
> net_device *dev,
> /* replace the compressed UDP head by the uncompressed UDP
>* header
>*/
> - new = skb_copy_expand(skb, sizeof(struct udphdr),
> + skb = skb_copy_expand(skb, sizeof(struct udphdr),
> skb_tailroom(skb), GFP_ATOMIC);
> - kfree_skb(skb);
> -
> - if (!new)
> - return -ENOMEM;
> + if (!skb) {
> + err = -ENOMEM;
> + goto drop;
> +
[Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
Currently there are a number of error paths in the lowpan_rcv function that
free the skb before returning, the patch simplifies the receive path by
ensuring that the skb is only freed from this function.
Passing the skb from 6lowpan up to the higher layers is not a
function of IPHC. By moving it out of IPHC we also remove the
need to support error code returns with NET_RX codes.
It also makes the lowpan_rcv function more extendable as we
can support more compression schemes.
With the above 2 lowpan_rcv is refacored so eliminate incorrect return values.
Signed-off-by: Martin Townsend
---
include/net/6lowpan.h | 4 +--
net/6lowpan/iphc.c| 74 ++-
net/bluetooth/6lowpan.c | 26 +--
net/ieee802154/6lowpan_rtnl.c | 55
4 files changed, 83 insertions(+), 76 deletions(-)
diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index d184df1..450eaaf 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16
*dgram_offset)
typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
- u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
+ u8 iphc0, u8 iphc1);
int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
unsigned short type, const void *_daddr,
const void *_saddr, unsigned int len);
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 142eef5..d51e8bb 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct
sk_buff *skb,
return 0;
}
-static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
- struct net_device *dev, skb_delivery_cb deliver_skb)
-{
- struct sk_buff *new;
- int stat;
-
- new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
- GFP_ATOMIC);
- kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
-
- skb_push(new, sizeof(struct ipv6hdr));
- skb_reset_network_header(new);
- skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
-
- new->protocol = htons(ETH_P_IPV6);
- new->pkt_type = PACKET_HOST;
- new->dev = dev;
-
- raw_dump_table(__func__, "raw skb data dump before receiving",
- new->data, new->len);
-
- stat = deliver_skb(new, dev);
-
- kfree_skb(new);
-
- return stat;
-}
-
/* Uncompress function for multicast destination address,
* when M bit is set.
*/
@@ -332,14 +301,15 @@ err:
/* TTL uncompression values */
static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
const u8 *saddr, const u8 saddr_type, const u8
saddr_len,
const u8 *daddr, const u8 daddr_type, const u8
daddr_len,
- u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
+ u8 iphc0, u8 iphc1)
{
struct ipv6hdr hdr = {};
u8 tmp, num_context = 0;
- int err;
+ int err = -EINVAL;
+ struct sk_buff *skb = *skb_inout;
raw_dump_table(__func__, "raw skb data dump uncompressed",
skb->data, skb->len);
@@ -460,7 +430,6 @@ int lowpan_process_data(struct sk_buff *skb, struct
net_device *dev,
/* UDP data uncompression */
if (iphc0 & LOWPAN_IPHC_NH_C) {
struct udphdr uh;
- struct sk_buff *new;
if (uncompress_udp_header(skb, &uh))
goto drop;
@@ -468,14 +437,15 @@ int lowpan_process_data(struct sk_buff *skb, struct
net_device *dev,
/* replace the compressed UDP head by the uncompressed UDP
* header
*/
- new = skb_copy_expand(skb, sizeof(struct udphdr),
+ skb = skb_copy_expand(skb, sizeof(struct udphdr),
skb_tailroom(skb), GFP_ATOMIC);
- kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
+ if (!skb) {
+ err = -ENOMEM;
+ goto drop;
+ }
- skb = new;
+ kfree_skb(*skb_inout);
+ *skb_inout = skb;
skb_push(skb, sizeof(struct udphdr));
skb_reset_transport_header(skb);
@@ -4
[Linux-zigbee-devel] [PATCH v3 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv
Currently there are a number of error paths in the lowpan_rcv function that
free the skb before returning, the patch simplifies the receive path by
ensuring that the skb is only freed from this function.
Passing the skb from 6lowpan up to the higher layers is not a
function of IPHC. By moving it out of IPHC we also remove the
need to support error code returns with NET_RX codes.
It also makes the lowpan_rcv function more extendable as we
can support more compression schemes.
With the above 2 lowpan_rcv is refacored so eliminate incorrect return values.
Signed-off-by: Martin Townsend
---
include/net/6lowpan.h | 4 +--
net/6lowpan/iphc.c| 74 ++-
net/bluetooth/6lowpan.c | 26 +--
net/ieee802154/6lowpan_rtnl.c | 55
4 files changed, 83 insertions(+), 76 deletions(-)
diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index d184df1..450eaaf 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16
*dgram_offset)
typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
- u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
+ u8 iphc0, u8 iphc1);
int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
unsigned short type, const void *_daddr,
const void *_saddr, unsigned int len);
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 142eef5..d51e8bb 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct
sk_buff *skb,
return 0;
}
-static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
- struct net_device *dev, skb_delivery_cb deliver_skb)
-{
- struct sk_buff *new;
- int stat;
-
- new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
- GFP_ATOMIC);
- kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
-
- skb_push(new, sizeof(struct ipv6hdr));
- skb_reset_network_header(new);
- skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
-
- new->protocol = htons(ETH_P_IPV6);
- new->pkt_type = PACKET_HOST;
- new->dev = dev;
-
- raw_dump_table(__func__, "raw skb data dump before receiving",
- new->data, new->len);
-
- stat = deliver_skb(new, dev);
-
- kfree_skb(new);
-
- return stat;
-}
-
/* Uncompress function for multicast destination address,
* when M bit is set.
*/
@@ -332,14 +301,15 @@ err:
/* TTL uncompression values */
static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
const u8 *saddr, const u8 saddr_type, const u8
saddr_len,
const u8 *daddr, const u8 daddr_type, const u8
daddr_len,
- u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
+ u8 iphc0, u8 iphc1)
{
struct ipv6hdr hdr = {};
u8 tmp, num_context = 0;
- int err;
+ int err = -EINVAL;
+ struct sk_buff *skb = *skb_inout;
raw_dump_table(__func__, "raw skb data dump uncompressed",
skb->data, skb->len);
@@ -460,7 +430,6 @@ int lowpan_process_data(struct sk_buff *skb, struct
net_device *dev,
/* UDP data uncompression */
if (iphc0 & LOWPAN_IPHC_NH_C) {
struct udphdr uh;
- struct sk_buff *new;
if (uncompress_udp_header(skb, &uh))
goto drop;
@@ -468,14 +437,15 @@ int lowpan_process_data(struct sk_buff *skb, struct
net_device *dev,
/* replace the compressed UDP head by the uncompressed UDP
* header
*/
- new = skb_copy_expand(skb, sizeof(struct udphdr),
+ skb = skb_copy_expand(skb, sizeof(struct udphdr),
skb_tailroom(skb), GFP_ATOMIC);
- kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
+ if (!skb) {
+ err = -ENOMEM;
+ goto drop;
+ }
- skb = new;
+ kfree_skb(*skb_inout);
+ *skb_inout = skb;
skb_push(skb, sizeof(struct udphdr));
skb_reset_transport_header(skb);
@@ -4
