Patch for "ETH_P_ALL_NO_NIT"

[Atkinson Stephen-G19998 <satkinson@xxxxxxxxxxxx>]

I would like to be able to receive all packets (regardless of type) on 
a given net_device. One way to do this would be to use ETH_P_ALL
however, ETH_P_ALL has two meanings, 1) receive all packets and 2) behave 
as a "NIT" (Network Interface Tap?). The NIT functionality causes packets
transmitted on the net_device in question to be "received" by an ETH_P_ALL
socket, unless the packet was sent by that socket.

So, I'd like to propose a new ethernet type (ETH_P_ALL_NO_NIT) which 
would behave like ETH_P_ALL without the side effects of NIT.

I've included a patch for ETH_P_ALL_NO_NIT below.

Comments?

Signed-off-by: Steve Atkinson <satkinson@xxxxxxxxxxxx>

--- linux-2.6.9_orig/include/linux/if_ether.h   2004-10-18 17:54:37.000000000 
-0400
+++ linux-2.6.9/include/linux/if_ether.h        2005-05-31 10:32:50.000000000 
-0400
@@ -91,6 +91,7 @@
 #define ETH_P_IRDA     0x0017          /* Linux-IrDA                   */
 #define ETH_P_ECONET   0x0018          /* Acorn Econet                 */
 #define ETH_P_HDLC     0x0019          /* HDLC frames                  */
+#define ETH_P_ALL_NO_NIT       0x0020  /* Every packet but DON'T ENABLE 
netdev_nit */
 
 /*
  *     This is an Ethernet frame header.
--- linux-2.6.9_orig/net/core/dev.c     2004-10-18 17:54:08.000000000 -0400
+++ linux-2.6.9/net/core/dev.c  2005-05-31 10:56:50.000000000 -0400
@@ -276,7 +276,10 @@
        if (pt->type == htons(ETH_P_ALL)) {
                netdev_nit++;
                list_add_rcu(&pt->list, &ptype_all);
-       } else {
+       } else if(pt->type == htons(ETH_P_ALL_NO_NIT)) {
+               list_add_rcu(&pt->list, &ptype_all);
+       }
+       else {
                hash = ntohs(pt->type) & 15;
                list_add_rcu(&pt->list, &ptype_base[hash]);
        }
@@ -310,9 +313,11 @@
        if (pt->type == htons(ETH_P_ALL)) {
                netdev_nit--;
                head = &ptype_all;
-       } else
+       } else if (pt->type == htons(ETH_P_ALL_NO_NIT)) {
+               head = &ptype_all;
+       } else {
                head = &ptype_base[ntohs(pt->type) & 15];
-
+       }
        list_for_each_entry(pt1, head, list) {
                if (pt == pt1) {
                        list_del_rcu(&pt->list);
@@ -1072,9 +1077,10 @@
                /* Never send packets back to the socket
                 * they originated from - MvS (miquels@xxxxxxxxxxxxxx)
                 */
-               if ((ptype->dev == dev || !ptype->dev) &&
-                   (ptype->af_packet_priv == NULL ||
-                    (struct sock *)ptype->af_packet_priv != skb->sk)) {
+               if ( (ptype->type != ETH_P_ALL_NO_NIT)  &&
+                         (ptype->dev == dev || !ptype->dev) &&
+                         (ptype->af_packet_priv == NULL ||
+                               (struct sock *)ptype->af_packet_priv != 
skb->sk)) {
                        struct sk_buff *skb2= skb_clone(skb, GFP_ATOMIC);
                        if (!skb2)
                                break;