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Subject[PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address
[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;
+
+ 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);
}

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