Re: [PATCH v2] staging: wilc1000: Use common structs to parse ip packets

From: Claudiu Beznea <Claudiu.Beznea@microchip.com>
To: Thibaut Robert <thibaut.robert@gmail.com>,
	Aditya Shankar <aditya.shankar@microchip.com>,
	Ganesh Krishna <ganesh.krishna@microchip.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	<linux-wireless@vger.kernel.org>, <devel@driverdev.osuosl.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] staging: wilc1000: Use common structs to parse ip packets
Date: Tue, 26 Jun 2018 10:55:30 +0300	[thread overview]
Message-ID: <333f9414-9541-dc33-9c69-4054b5966eaa@microchip.com> (raw)
In-Reply-To: <20180619184419.10304-1-thibaut.robert@gmail.com>

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>

On 19.06.2018 21:44, Thibaut Robert wrote:
> Use structs ethhdr, iphdr and tcphdr instead of manual parsing in
> tcp_process.
> This commit fix handling of ip packets containing options.
> It also fixes the following sparse warning:
> 
> drivers/staging/wilc1000//wilc_wlan.c:201:19: warning: cast to restricted __be16
> 
> Signed-off-by: Thibaut Robert <thibaut.robert@gmail.com>
> ---
>  drivers/staging/wilc1000/wilc_wlan.c | 43 ++++++++++------------------
>  1 file changed, 15 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/staging/wilc1000/wilc_wlan.c b/drivers/staging/wilc1000/wilc_wlan.c
> index 55755d7fbb30..85af36595e69 100644
> --- a/drivers/staging/wilc1000/wilc_wlan.c
> +++ b/drivers/staging/wilc1000/wilc_wlan.c
> @@ -1,4 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
> +#include <linux/if_ether.h>
> +#include <linux/ip.h>
>  #include "wilc_wfi_netdevice.h"
>  #include "wilc_wlan_cfg.h"
>  
> @@ -150,9 +152,8 @@ static inline int add_tcp_pending_ack(u32 ack, u32 session_index,
>  
>  static inline void tcp_process(struct net_device *dev, struct txq_entry_t *tqe)
>  {
> -	u8 *eth_hdr_ptr;
> -	u8 *buffer = tqe->buffer;
> -	unsigned short h_proto;
> +	void *buffer = tqe->buffer;
> +	const struct ethhdr *eth_hdr_ptr = buffer;
>  	int i;
>  	unsigned long flags;
>  	struct wilc_vif *vif;
> @@ -163,37 +164,23 @@ static inline void tcp_process(struct net_device *dev, struct txq_entry_t *tqe)
>  
>  	spin_lock_irqsave(&wilc->txq_spinlock, flags);
>  
> -	eth_hdr_ptr = &buffer[0];
> -	h_proto = ntohs(*((unsigned short *)&eth_hdr_ptr[12]));
> -	if (h_proto == ETH_P_IP) {
> -		u8 *ip_hdr_ptr;
> -		u8 protocol;
> +	if (eth_hdr_ptr->h_proto == htons(ETH_P_IP)) {
> +		const struct iphdr *ip_hdr_ptr = buffer + ETH_HLEN;
>  
> -		ip_hdr_ptr = &buffer[ETHERNET_HDR_LEN];
> -		protocol = ip_hdr_ptr[9];
> -
> -		if (protocol == 0x06) {
> -			u8 *tcp_hdr_ptr;
> +		if (ip_hdr_ptr->protocol == IPPROTO_TCP) {
> +			const struct tcphdr *tcp_hdr_ptr;
>  			u32 IHL, total_length, data_offset;
>  
> -			tcp_hdr_ptr = &ip_hdr_ptr[IP_HDR_LEN];
> -			IHL = (ip_hdr_ptr[0] & 0xf) << 2;
> -			total_length = ((u32)ip_hdr_ptr[2] << 8) +
> -					(u32)ip_hdr_ptr[3];
> -			data_offset = ((u32)tcp_hdr_ptr[12] & 0xf0) >> 2;
> +			IHL = ip_hdr_ptr->ihl << 2;
> +			tcp_hdr_ptr = buffer + ETH_HLEN + IHL;
> +			total_length = ntohs(ip_hdr_ptr->tot_len);
> +
> +			data_offset = tcp_hdr_ptr->doff << 2;
>  			if (total_length == (IHL + data_offset)) {
>  				u32 seq_no, ack_no;
>  
> -				seq_no = ((u32)tcp_hdr_ptr[4] << 24) +
> -					 ((u32)tcp_hdr_ptr[5] << 16) +
> -					 ((u32)tcp_hdr_ptr[6] << 8) +
> -					 (u32)tcp_hdr_ptr[7];
> -
> -				ack_no = ((u32)tcp_hdr_ptr[8] << 24) +
> -					 ((u32)tcp_hdr_ptr[9] << 16) +
> -					 ((u32)tcp_hdr_ptr[10] << 8) +
> -					 (u32)tcp_hdr_ptr[11];
> -
> +				seq_no = ntohl(tcp_hdr_ptr->seq);
> +				ack_no = ntohl(tcp_hdr_ptr->ack_seq);
>  				for (i = 0; i < tcp_session; i++) {
>  					u32 j = ack_session_info[i].seq_num;
>  
>