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SubjectRe: [PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address
Andrew Morton wrote:
> On Fri, 22 Aug 2008 11:39:08 -0700
> Karen Xie <kxie@chelsio.com> wrote:
>
>
>> [PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address
>>
>> From: Karen Xie <kxie@chelsio.com>
>>
>> stg can be tricky ...
>> [adding @adapter in cxgb3_arp_process doxygen header]
>> The accelerated iSCSI traffic uses a private IP address unknown to the OS.
>> The driver has to reply to ARP requests dedicated to the private IP address.
>>
>> Signed-off-by: Divy Le Ray <divy@chelsio.com>
>> ---
>>
>> drivers/net/cxgb3/sge.c | 71 ++++++++++++++++++++++++++++++++++++++++++++---
>> 1 files changed, 66 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
>> index 1b0861d..d2a9285 100644
>> --- a/drivers/net/cxgb3/sge.c
>> +++ b/drivers/net/cxgb3/sge.c
>> @@ -36,6 +36,7 @@
>> #include <linux/ip.h>
>> #include <linux/tcp.h>
>> #include <linux/dma-mapping.h>
>> +#include <net/arp.h>
>> #include "common.h"
>> #include "regs.h"
>> #include "sge_defs.h"
>> @@ -1859,6 +1860,54 @@ static void restart_tx(struct sge_qset *qs)
>> }
>>
>> /**
>> + * cxgb3_arp_process - process an ARP request probing a private IP address
>> + * @adapter: the adapter
>> + * @skb: the skbuff containing the ARP request
>> + *
>> + * Check if the ARP request is probing the private IP address
>> + * dedicated to iSCSI, generate an ARP reply if so.
>> + */
>> +static void cxgb3_arp_process(struct adapter *adapter, struct sk_buff *skb)
>> +{
>> + struct net_device *dev = skb->dev;
>> + struct port_info *pi;
>> + struct arphdr *arp;
>> + unsigned char *arp_ptr;
>> + unsigned char *sha;
>> + u32 sip, tip;
>> +
>> + if (!dev)
>> + return;
>>
>
> Can this happen?
>
>
>> + skb_reset_network_header(skb);
>> + arp = arp_hdr(skb);
>> +
>> + if (arp->ar_op != htons(ARPOP_REQUEST))
>> + return;
>> +
>> + arp_ptr = (unsigned char *)(arp + 1);
>> + sha = arp_ptr;
>> + arp_ptr += dev->addr_len;
>> + memcpy(&sip, arp_ptr, 4);
>> + arp_ptr += 4;
>> + arp_ptr += dev->addr_len;
>> + memcpy(&tip, arp_ptr, 4);
>>
>
> Should arp_hdr_len() be used here?
>
>
>> + pi = netdev_priv(dev);
>> + if (ntohl(tip) != pi->iscsi_ipaddr)
>> + return;
>> +
>> + arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
>> + dev->dev_addr, sha);
>> +
>> +}
>> +
>> +static inline int is_arp(struct sk_buff *skb)
>> +{
>> + return skb->protocol == htons(ETH_P_ARP);
>>
>
> Other net code uses __constant_htons() for this.
>
> (Dunno why - if it makes a difference, htons() is broken?)
>
>
>
Doesn't this avoid complaints from sparse endian checking?




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