[PATCH 2/4 2.6.28] cxgb3 - handle ARP replies for private iSCSI IP address

From: Karen Xie <[EMAIL PROTECTED]>

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 |   72 ++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 67 insertions(+), 5 deletions(-)


diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c
index 1b0861d..2f17cf3 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;
+       __be32 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, sizeof(sip));
+       arp_ptr += sizeof(sip);
+       arp_ptr += dev->addr_len;
+       memcpy(&tip, arp_ptr, sizeof(tip));
+
+       pi = netdev_priv(dev);
+       if (tip != pi->iscsi_ipv4addr)
+               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 +1940,35 @@ 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_ipv4addr &&
+                                            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_ipv4addr && is_arp(skb)))
+                               cxgb3_arp_process(adap, skb);
                        netif_receive_skb(skb);
+               }
        } else
                netif_rx(skb);
 }

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