3 files changed, 11 insertions, 18 deletions
diff --git a/firmware/microblaze/apps/txrx.c b/firmware/microblaze/apps/txrx.c
index 9c3caa4f2..1b3299150 100644
--- a/firmware/microblaze/apps/txrx.c
+++ b/firmware/microblaze/apps/txrx.c
@@ -504,16 +504,22 @@ void handle_udp_ctrl_packet(
 static bool
 eth_pkt_inspector(dbsm_t *sm, int bufno)
 {
-  //extract buffer point and length
+  //point me to the ethernet frame
   uint32_t *buff = (uint32_t *)buffer_ram(bufno);
-  size_t len = buffer_pool_status->last_line[bufno] - 3;
 
   //treat this as fast-path data?
-  if (is_udp_packet_with_vrt(buff, len, USRP2_UDP_DATA_PORT)){
-    return false;
-  }
+  // We have to do this operation as fast as possible.
+  // Therefore, we do not check all the headers,
+  // just check that the udp port matches
+  // and that the vrt header is non zero.
+  // In the future, a hardware state machine will do this...
+  if ( //warning! magic numbers approaching....
+      (((buff + ((2 + 14 + 20)/sizeof(uint32_t)))[0] & 0xffff) == USRP2_UDP_DATA_PORT) &&
+      ((buff + ((2 + 14 + 20 + 8)/sizeof(uint32_t)))[0] != 0)
+  ) return false;
 
   //pass it to the slow-path handler
+  size_t len = buffer_pool_status->last_line[bufno] - 3;
   handle_eth_packet(buff, len);
   return true;
 }
diff --git a/firmware/microblaze/lib/net_common.c b/firmware/microblaze/lib/net_common.c
index ab7aadca9..693502d18 100644
--- a/firmware/microblaze/lib/net_common.c
+++ b/firmware/microblaze/lib/net_common.c
@@ -378,17 +378,6 @@ handle_arp_packet(struct arp_eth_ipv4 *p, size_t size)
   }
 }
 
-bool is_udp_packet_with_vrt(uint32_t *p, size_t nlines, int port){
-    struct ip_hdr *ip = (struct ip_hdr *)(p + 4);
-    struct udp_hdr *udp = (struct udp_hdr *)(((char *)ip) + IP_HLEN);
-    uint32_t *payload = (uint32_t *)(((char *)udp) + UDP_HLEN);
-    return \
-        (p[3] & 0xffff) == ETHERTYPE_IPV4 &&
-        IPH_PROTO(ip) == IP_PROTO_UDP &&
-        udp->dest == port &&
-        payload[0] != 0; //must be non zero vrt header
-}
-
 void
 handle_eth_packet(uint32_t *p, size_t nlines)
 {
diff --git a/firmware/microblaze/lib/net_common.h b/firmware/microblaze/lib/net_common.h
index 1a7052f71..6cd45bf69 100644
--- a/firmware/microblaze/lib/net_common.h
+++ b/firmware/microblaze/lib/net_common.h
@@ -56,6 +56,4 @@ void send_udp_pkt(int src_port, struct socket_address dst,
 
 void handle_eth_packet(uint32_t *p, size_t nlines);
 
-bool is_udp_packet_with_vrt(uint32_t *p, size_t nlines, int port);
-
 #endif /* INCLUDED_NET_COMMON_H */