if_ethersubr patch

# cat if_ethersubr.c.patch
*** if_ethersubr.c      Fri Jan 13 09:52:49 2012
--- if_ethersubr.c_     Sun Oct 30 19:40:28 2011
***************
*** 622,627 ****
--- 622,633 ----
                ifp->if_imcasts++;
        }

+       m->m_flags |= M_FLOWID;
+       m->m_pkthdr.flowid =  eh->ether_dhost[0] + eh->ether_dhost[1] + eh->ether_dhost[2] + eh->ether_dhost[3] + eh->ether_dhost[4] + eh->ether_dhost[5];
+       m->m_pkthdr.flowid += eh->ether_shost[0] + eh->ether_shost[1] + eh->ether_shost[2] + eh->ether_shost[3] + eh->ether_shost[4] + eh->ether_shost[5];
+
+
+
  #ifdef MAC
        /*
         * Tag the mbuf with an appropriate MAC label before any other
***************
*** 873,878 ****
--- 879,908 ----
                if ((m = ip_fastforward(m)) == NULL)
                        return;
                isr = NETISR_IP;
+
+               struct ipheader {
+                   u_char offset [12]; //ip header fields not actually needed here
+                   u_char src [4]; //ip src
+                   u_char dst [4]; //ip dst
+               } __packed __aligned(4);
+
+               if (m->m_pkthdr.len < sizeof(struct ipheader)) {                //from ip_fastforward
+                   if_printf(ifp, "flowid math: discard frame with too small header\n");
+                   goto discard;
+               }
+               if (m->m_len < sizeof (struct ipheader) &&
+                   (m = m_pullup(m, sizeof (struct ipheader))) == NULL) {      //ip_fastforward
+                   if_printf(ifp, "flowid math: discard frame at pullup\n");
+                       return;         /* mbuf already free'd */
+               }
+               struct ipheader *ip;
+               ip = mtod(m, struct ipheader *);
+               m->m_pkthdr.flowid += ip->src[0] + ip->src[1] + ip->src[2] + ip->src[3];
+               m->m_pkthdr.flowid += ip->dst[0] + ip->dst[1] + ip->dst[2] + ip->dst[3];
+
+               //if_printf(ifp, "Calculated flow id %d\n", m->m_pkthdr.flowid);
+
+
                break;

        case ETHERTYPE_ARP: