[PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address
From: Karen Xie <[email protected]>
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 <[email protected]>
---
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;
+
+ 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);
+
+ 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);
+}
+
+/**
* rx_eth - process an ingress ethernet packet
* @adap: the adapter
* @rq: the response queue that received the packet
@@ -1882,7 +1931,7 @@ static void rx_eth(struct adapter *adap, struct sge_rspq *rq,
pi = netdev_priv(skb->dev);
if (pi->rx_csum_offload && p->csum_valid && p->csum == htons(0xffff) &&
!p->fragment) {
- rspq_to_qset(rq)->port_stats[SGE_PSTAT_RX_CSUM_GOOD]++;
+ qs->port_stats[SGE_PSTAT_RX_CSUM_GOOD]++;
skb->ip_summed = CHECKSUM_UNNECESSARY;
} else
skb->ip_summed = CHECKSUM_NONE;
@@ -1891,22 +1940,34 @@ static void rx_eth(struct adapter *adap, struct sge_rspq *rq,
struct vlan_group *grp = pi->vlan_grp;
qs->port_stats[SGE_PSTAT_VLANEX]++;
- if (likely(grp))
+
+ if (likely(grp)) {
if (lro)
lro_vlan_hwaccel_receive_skb(&qs->lro_mgr, skb,
grp,
ntohs(p->vlan),
p);
- else
+ else {
+ if (unlikely(pi->iscsi_ipaddr && is_arp(skb))) {
+ unsigned short vtag = ntohs(p->vlan) &
+ VLAN_VID_MASK;
+ skb->dev = vlan_group_get_device(grp,
+ vtag);
+ cxgb3_arp_process(adap, skb);
+ }
__vlan_hwaccel_rx(skb, grp, ntohs(p->vlan),
rq->polling);
- else
+ }
+ } else
dev_kfree_skb_any(skb);
} else if (rq->polling) {
if (lro)
lro_receive_skb(&qs->lro_mgr, skb, p);
- else
+ else {
+ if (unlikely(pi->iscsi_ipaddr && is_arp(skb)))
+ cxgb3_arp_process(adap, skb);
netif_receive_skb(skb);
+ }
} else
netif_rx(skb);
}
On Fri, 22 Aug 2008 11:39:08 -0700
Karen Xie <[email protected]> wrote:
> [PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address
>
> From: Karen Xie <[email protected]>
>
> 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 <[email protected]>
> ---
>
> 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?)
Andrew Morton wrote:
> On Fri, 22 Aug 2008 11:39:08 -0700
> Karen Xie <[email protected]> wrote:
>
>
>> [PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address
>>
>> From: Karen Xie <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>>
>> 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?
On Fri, 22 Aug 2008 12:12:50 -0700
Andrew Morton <[email protected]> wrote:
> On Fri, 22 Aug 2008 11:39:08 -0700
> Karen Xie <[email protected]> wrote:
>
> > [PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address
> >
> > From: Karen Xie <[email protected]>
> >
> > 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 <[email protected]>
> > ---
> >
> > 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.
htons() goes through several levels of indirection to make sure
that if argument is constant, no code is necessary. The practice is
reserve __constant_htons() only for those cases like initialization and case
statements where C won't allow it.