Re: [PATCH bluetooth-next 3/6] 6lowpan: introduce LOWPAN_IPHC_MAX_HC_BUF_LEN

[Jukka Rissanen <jukka.rissanen@linux.intel.com>]

Hi Alex,

Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>


On ti, 2015-10-13 at 13:42 +0200, Alexander Aring wrote:
> This patch introduces the LOWPAN_IPHC_MAX_HC_BUF_LEN define which
> represent the worst-case supported IPHC buffer length. It's used to
> allocate the stack buffer space for creating the IPHC header.
> 
> Signed-off-by: Alexander Aring <alex.aring@gmail.com>
> ---
>  include/net/6lowpan.h | 8 ++++++++
>  net/6lowpan/iphc.c    | 2 +-
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index 07db532..aa5a823 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -64,12 +64,20 @@
>  #define EUI64_ADDR_LEN		8
>  
>  #define LOWPAN_NHC_MAX_ID_LEN	1
> +/* Maximum next header compression length which we currently support inclusive
> + * possible inline data.
> + */
> +#define LOWPAN_NHC_MAX_HDR_LEN	(sizeof(struct udphdr))
>  /* Max IPHC Header len without IPv6 hdr specific inline data.
>   * Useful for getting the "extra" bytes we need at worst case compression.
>   *
>   * LOWPAN_IPHC + CID + LOWPAN_NHC_MAX_ID_LEN
>   */
>  #define LOWPAN_IPHC_MAX_HEADER_LEN	(2 + 1 + LOWPAN_NHC_MAX_ID_LEN)
> +/* Maximum worst case IPHC header buffer size */
> +#define LOWPAN_IPHC_MAX_HC_BUF_LEN	(sizeof(struct ipv6hdr) +	\
> +					 LOWPAN_IPHC_MAX_HEADER_LEN +	\
> +					 LOWPAN_NHC_MAX_HDR_LEN)
>  
>  /*
>   * ipv6 address based on mac
> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> index 78c8a49..dd5f27d 100644
> --- a/net/6lowpan/iphc.c
> +++ b/net/6lowpan/iphc.c
> @@ -429,7 +429,7 @@ int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
>  {
>  	u8 tmp, iphc0, iphc1, *hc_ptr;
>  	struct ipv6hdr *hdr;
> -	u8 head[100] = {};
> +	u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
>  	int ret, addr_type;
>  
>  	if (type != ETH_P_IPV6)


Cheers,
Jukka