2014-08-01 15:30:00

by Martin Townsend

[permalink] [raw]
Subject: [PATCH bluetooth-next] Simplify lowpan receive path so skb is freed in lowpan_rcv when dropped.

Signed-off-by: Martin Townsend <[email protected]>
---
include/net/6lowpan.h | 2 +-
net/6lowpan/iphc.c | 22 +++++++++++++---------
net/bluetooth/6lowpan.c | 12 ++++++++----
net/ieee802154/6lowpan_rtnl.c | 12 ++++++------
4 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index d7e9169..aa0381e 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -374,7 +374,7 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)

typedef int (*skb_delivery_cb)(struct sk_buff *skb);

-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);
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 92eed6d..ba47c01 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -179,11 +179,11 @@ static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,

new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
GFP_ATOMIC);
- kfree_skb(skb);
-
if (!new)
return -ENOMEM;

+ kfree_skb(skb);
+
skb_push(new, sizeof(struct ipv6hdr));
skb_reset_network_header(new);
skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
@@ -196,6 +196,8 @@ static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
new->data, new->len);

stat = deliver_skb(new);
+ if (stat < 0)
+ stat = NET_RX_DROP;

kfree_skb(new);

@@ -333,7 +335,7 @@ 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)
@@ -341,6 +343,8 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
struct ipv6hdr hdr = {};
u8 tmp, num_context = 0;
int err;
+ int err_ret = -EINVAL;
+ struct sk_buff *skb = *skb_inout;

raw_dump_table(__func__, "raw skb data dump uncompressed",
skb->data, skb->len);
@@ -471,11 +475,12 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
*/
new = skb_copy_expand(skb, sizeof(struct udphdr),
skb_tailroom(skb), GFP_ATOMIC);
+ if (!new) {
+ err_ret = -ENOMEM;
+ goto drop;
+ }
+
kfree_skb(skb);
-
- if (!new)
- return -ENOMEM;
-
skb = new;

skb_push(skb, sizeof(struct udphdr));
@@ -503,8 +508,7 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
return skb_deliver(skb, &hdr, dev, deliver_skb);

drop:
- kfree_skb(skb);
- return -EINVAL;
+ return err_ret;
}
EXPORT_SYMBOL_GPL(lowpan_process_data);

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index f5df93f..38a2987 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -215,7 +215,7 @@ static int give_skb_to_upper(struct sk_buff *skb)
return ret;
}

-static int process_data(struct sk_buff *skb, struct net_device *netdev,
+static int process_data(struct sk_buff **skb_inout, struct net_device *netdev,
struct l2cap_chan *chan)
{
const u8 *saddr, *daddr;
@@ -223,6 +223,7 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
struct lowpan_dev *dev;
struct lowpan_peer *peer;
unsigned long flags;
+ struct sk_buff *skb = *skb_inout;

dev = lowpan_dev(netdev);

@@ -245,13 +246,12 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
if (lowpan_fetch_skb_u8(skb, &iphc1))
goto drop;

- return lowpan_process_data(skb, netdev,
+ return lowpan_process_data(skb_inout, netdev,
saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
iphc0, iphc1, give_skb_to_upper);

drop:
- kfree_skb(skb);
return -EINVAL;
}

@@ -300,7 +300,11 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
if (!local_skb)
goto drop;

- ret = process_data(local_skb, dev, chan);
+ ret = process_data(&local_skb, dev, chan);
+ if (ret < 0) {
+ kfree_skb(local_skb);
+ goto drop;
+ }
if (ret != NET_RX_SUCCESS)
goto drop;

diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index 3154775..3ae7646 100644
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c
@@ -166,11 +166,12 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb)
return stat;
}

-static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
+static int process_data(struct sk_buff **skb_inout, const struct ieee802154_hdr *hdr)
{
u8 iphc0, iphc1;
struct ieee802154_addr_sa sa, da;
void *sap, *dap;
+ struct sk_buff *skb = *skb_inout;

raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
/* at least two bytes will be used for the encoding */
@@ -196,13 +197,12 @@ static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
else
dap = &da.hwaddr;

- return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
+ return lowpan_process_data(skb_inout, skb->dev, sap, sa.addr_type,
IEEE802154_ADDR_LEN, dap, da.addr_type,
IEEE802154_ADDR_LEN, iphc0, iphc1,
lowpan_give_skb_to_devices);

drop:
- kfree_skb(skb);
return -EINVAL;
}

@@ -485,14 +485,14 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
} else {
switch (skb->data[0] & 0xe0) {
case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
- ret = process_data(skb, &hdr);
+ ret = process_data(&skb, &hdr);
if (ret == NET_RX_DROP)
goto drop;
break;
case LOWPAN_DISPATCH_FRAG1: /* first fragment header */
ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
if (ret == 1) {
- ret = process_data(skb, &hdr);
+ ret = process_data(&skb, &hdr);
if (ret == NET_RX_DROP)
goto drop;
}
@@ -500,7 +500,7 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */
ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
if (ret == 1) {
- ret = process_data(skb, &hdr);
+ ret = process_data(&skb, &hdr);
if (ret == NET_RX_DROP)
goto drop;
}
--
1.9.1


2014-08-02 06:42:02

by Martin Townsend

[permalink] [raw]
Subject: Re: [PATCH bluetooth-next] Simplify lowpan receive path so skb is freed in lowpan_rcv when dropped.

I've just realised I've forgot to ensure skb_inout now points to the new
skb when copy expanding.
Sorry about that, I'll respin the patch.

- Martin.

On 01/08/14 16:45, Marc Kleine-Budde wrote:
> On 08/01/2014 05:30 PM, Martin Townsend wrote:
>> Signed-off-by: Martin Townsend <[email protected]>
>> ---
>> include/net/6lowpan.h | 2 +-
>> net/6lowpan/iphc.c | 22 +++++++++++++---------
>> net/bluetooth/6lowpan.c | 12 ++++++++----
>> net/ieee802154/6lowpan_rtnl.c | 12 ++++++------
>> 4 files changed, 28 insertions(+), 20 deletions(-)
>>
>> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
>> index d7e9169..aa0381e 100644
>> --- a/include/net/6lowpan.h
>> +++ b/include/net/6lowpan.h
>> @@ -374,7 +374,7 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
>>
>> typedef int (*skb_delivery_cb)(struct sk_buff *skb);
>>
>> -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,
> Why do you make the first parameter a double pointer?
>
> Marc
>

2014-08-01 15:56:55

by Martin Townsend

[permalink] [raw]
Subject: Re: [PATCH bluetooth-next] Simplify lowpan receive path so skb is freed in lowpan_rcv when dropped.

Later on in lowpan_process_data and in a another function IIRC the skb could potentially be copy expanded as we are uncompressing which results in a new skb.

- Martin.


On 01/08/14 16:45, Marc Kleine-Budde wrote:
> On 08/01/2014 05:30 PM, Martin Townsend wrote:
>> Signed-off-by: Martin Townsend <[email protected]>
>> ---
>> include/net/6lowpan.h | 2 +-
>> net/6lowpan/iphc.c | 22 +++++++++++++---------
>> net/bluetooth/6lowpan.c | 12 ++++++++----
>> net/ieee802154/6lowpan_rtnl.c | 12 ++++++------
>> 4 files changed, 28 insertions(+), 20 deletions(-)
>>
>> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
>> index d7e9169..aa0381e 100644
>> --- a/include/net/6lowpan.h
>> +++ b/include/net/6lowpan.h
>> @@ -374,7 +374,7 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
>>
>> typedef int (*skb_delivery_cb)(struct sk_buff *skb);
>>
>> -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,
> Why do you make the first parameter a double pointer?
>
> Marc
>

2014-08-01 15:45:20

by Marc Kleine-Budde

[permalink] [raw]
Subject: Re: [PATCH bluetooth-next] Simplify lowpan receive path so skb is freed in lowpan_rcv when dropped.

On 08/01/2014 05:30 PM, Martin Townsend wrote:
> Signed-off-by: Martin Townsend <[email protected]>
> ---
> include/net/6lowpan.h | 2 +-
> net/6lowpan/iphc.c | 22 +++++++++++++---------
> net/bluetooth/6lowpan.c | 12 ++++++++----
> net/ieee802154/6lowpan_rtnl.c | 12 ++++++------
> 4 files changed, 28 insertions(+), 20 deletions(-)
>
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index d7e9169..aa0381e 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -374,7 +374,7 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
>
> typedef int (*skb_delivery_cb)(struct sk_buff *skb);
>
> -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,

Why do you make the first parameter a double pointer?

Marc

--
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