usrp2: work on alternative stream destination

11 files changed, 287 insertions, 130 deletions

diff --git a/firmware/zpu/apps/txrx_uhd.c b/firmware/zpu/apps/txrx_uhd.c
index 9daf441e2..a4bfce0ec 100644
--- a/firmware/zpu/apps/txrx_uhd.c
+++ b/firmware/zpu/apps/txrx_uhd.c
@@ -92,8 +92,35 @@ static void handle_udp_data_packet(
     default: return;
     }
 
-    eth_mac_addr_t eth_mac_host; arp_cache_lookup_mac(&src.addr, &eth_mac_host);
-    setup_framer(eth_mac_host, *ethernet_mac_addr(), src, dst, which);
+    //assume the packet destination is the packet source
+    //the arp cache lookup should never fail for this case
+    const struct socket_address src_addr = dst;
+    struct socket_address dst_addr = src;
+    eth_mac_addr_t eth_mac_dst;
+    arp_cache_lookup_mac(&dst_addr.addr, &eth_mac_dst);
+
+    //however, if this control packet has an alternative destination...
+    if (payload_len >= sizeof(usrp2_stream_ctrl_t)){
+
+        //parse the destination ip addr and udp port from the payload
+        const usrp2_stream_ctrl_t *stream_ctrl = (const usrp2_stream_ctrl_t *)payload;
+        dst_addr.addr.addr = stream_ctrl->ip_addr;
+        dst_addr.port = (uint16_t)stream_ctrl->udp_port;
+        struct ip_addr ip_dest = dst_addr.addr;
+
+        //are we in the subnet? if not use the gateway
+        const uint32_t subnet_mask = get_subnet()->addr;
+        const bool in_subnet = ((get_ip_addr()->addr & subnet_mask) == (ip_dest.addr & subnet_mask));
+        if (!in_subnet) ip_dest = *get_gateway();
+
+        //lookup the host ip address with ARP (this may fail)
+        const bool ok = arp_cache_lookup_mac(&ip_dest, &eth_mac_dst);
+        if (!ok) net_common_send_arp_request(&ip_dest);
+        const uint32_t result = (ok)? 0 : ~0;
+        send_udp_pkt(dst.port, src, &result, sizeof(result));
+    }
+
+    setup_framer(eth_mac_dst, *ethernet_mac_addr(), dst_addr, src_addr, which);
 }
 
 #define OTW_GPIO_BANK_TO_NUM(bank) \
@@ -279,6 +306,7 @@ int
 main(void)
 {
   u2_init();
+  arp_cache_init();
 #ifdef BOOTLOADER
   putstr("\nUSRP N210 UDP bootloader\n");
 #else
@@ -294,8 +322,7 @@ main(void)
   //load the production FPGA image or firmware if appropriate
   do_the_bootload_thing();
   //if we get here we've fallen through to safe firmware
-  set_default_mac_addr();
-  set_default_ip_addr();
+  eth_addrs_set_default();
 #endif
 
   print_mac_addr(ethernet_mac_addr()); newline();
diff --git a/firmware/zpu/lib/eth_addrs.c b/firmware/zpu/lib/eth_addrs.c
index c45ce7559..6d3347cf3 100644
--- a/firmware/zpu/lib/eth_addrs.c
+++ b/firmware/zpu/lib/eth_addrs.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2011 Ettus Research LLC
+ * Copyright 2010-2012 Ettus Research LLC
  * Copyright 2007 Free Software Foundation, Inc.
  *
  * This program is free software: you can redistribute it and/or modify
@@ -20,6 +20,7 @@
 #include "memory_map.h"
 #include "nonstdio.h"
 #include <stdbool.h>
+#include <string.h>
 #include "i2c.h"
 #include "usrp2/fw_common.h"
 
@@ -37,104 +38,69 @@ unprogrammed(const void *t, size_t len)
   return all_ones | all_zeros;
 }
 
-//////////////////// MAC Addr Stuff ///////////////////////
+typedef struct{
+    eth_mac_addr_t mac_addr;
+    struct ip_addr ip_addr;
+    struct ip_addr gateway;
+    struct ip_addr subnet;
+} eth_addrs_t;
 
-static bool src_mac_addr_initialized = false;
+static bool eth_addrs_initialized = false;
 
-static const eth_mac_addr_t default_mac_addr = {{
-    0x00, 0x50, 0xC2, 0x85, 0x3f, 0xff
-  }};
+static const eth_addrs_t default_eth_addrs = {
+    .mac_addr = {{0x00, 0x50, 0xC2, 0x85, 0x3f, 0xff}},
+    .ip_addr = {(192 << 24 | 168 << 16 | 10  << 8  | 2 << 0)},
+    .gateway = {(192 << 24 | 168 << 16 | 10  << 8  | 1 << 0)},
+    .subnet  = {(255 << 24 | 255 << 16 | 255 << 8  | 0 << 0)},
+};
 
-static eth_mac_addr_t src_mac_addr = {{
-    0x00, 0x50, 0xC2, 0x85, 0x3f, 0xff
-  }};
-  
-void set_default_mac_addr(void)
-{
-    src_mac_addr_initialized = true;
-    src_mac_addr = default_mac_addr;
-}
+static eth_addrs_t current_eth_addrs;
 
-const eth_mac_addr_t *
-ethernet_mac_addr(void)
-{
-  if (!src_mac_addr_initialized){    // fetch from eeprom
-    src_mac_addr_initialized = true;
+static void eth_addrs_init(void){
+    if (eth_addrs_initialized) return;
+    eth_addrs_initialized = true;
 
-    // if we're simulating, don't read the EEPROM model, it's REALLY slow
-    if (hwconfig_simulation_p())
-      return &src_mac_addr;
-
-    eth_mac_addr_t tmp;
-    bool ok = eeprom_read(USRP2_I2C_ADDR_MBOARD, USRP2_EE_MBOARD_MAC_ADDR, &tmp, sizeof(tmp));
-    if (!ok || unprogrammed(&tmp, sizeof(tmp))){
-      // use the default
+    #define eth_addrs_init_x(addr, x){ \
+        const bool ok = eeprom_read(USRP2_I2C_ADDR_MBOARD, addr, &current_eth_addrs.x, sizeof(current_eth_addrs.x)); \
+        if (!ok || unprogrammed(&current_eth_addrs.x, sizeof(current_eth_addrs.x))){ \
+            memcpy(&current_eth_addrs.x, &default_eth_addrs.x, sizeof(current_eth_addrs.x)); \
+        } \
     }
-    else
-      src_mac_addr = tmp;
-  }
 
-  return &src_mac_addr;
-}
+    eth_addrs_init_x(USRP2_EE_MBOARD_MAC_ADDR, mac_addr);
+    eth_addrs_init_x(USRP2_EE_MBOARD_IP_ADDR,  ip_addr);
+    eth_addrs_init_x(USRP2_EE_MBOARD_GATEWAY,  gateway);
+    eth_addrs_init_x(USRP2_EE_MBOARD_SUBNET,   subnet);
 
-bool
-ethernet_set_mac_addr(const eth_mac_addr_t *t)
-{
-  bool ok = eeprom_write(USRP2_I2C_ADDR_MBOARD, USRP2_EE_MBOARD_MAC_ADDR, t, sizeof(eth_mac_addr_t));
-  if (ok){
-    src_mac_addr = *t;
-    src_mac_addr_initialized = true;
-    //eth_mac_set_addr(t); //this breaks the link
-  }
-
-  return ok;
 }
 
-//////////////////// IP Addr Stuff ///////////////////////
-
-static bool src_ip_addr_initialized = false;
-
-static const struct ip_addr default_ip_addr = {
-    (192 << 24 | 168 << 16 | 10 << 8 | 2 << 0)
-};
-
-static struct ip_addr src_ip_addr = {
-    (192 << 24 | 168 << 16 | 10 << 8 | 2 << 0)
-};
-
-void set_default_ip_addr(void)
-{
-    src_ip_addr_initialized = true;
-    src_ip_addr = default_ip_addr;
+const eth_mac_addr_t *ethernet_mac_addr(void){
+    eth_addrs_init();
+    return &current_eth_addrs.mac_addr;
 }
 
-const struct ip_addr *get_ip_addr(void)
-{
-  if (!src_ip_addr_initialized){    // fetch from eeprom
-    src_ip_addr_initialized = true;
-
-    // if we're simulating, don't read the EEPROM model, it's REALLY slow
-    if (hwconfig_simulation_p())
-      return &src_ip_addr;
+const struct ip_addr *get_ip_addr(void){
+    eth_addrs_init();
+    return &current_eth_addrs.ip_addr;
+}
 
-    struct ip_addr tmp;
-    bool ok = eeprom_read(USRP2_I2C_ADDR_MBOARD, USRP2_EE_MBOARD_IP_ADDR, &tmp, sizeof(tmp));
-    if (!ok || unprogrammed(&tmp, sizeof(tmp))){
-      // use the default
-    }
-    else
-      src_ip_addr = tmp;
-  }
+const struct ip_addr *get_subnet(void){
+    eth_addrs_init();
+    return &current_eth_addrs.subnet;
+}
 
-  return &src_ip_addr;
+const struct ip_addr *get_gateway(void){
+    eth_addrs_init();
+    return &current_eth_addrs.gateway;
 }
 
 bool set_ip_addr(const struct ip_addr *t){
-  bool ok = eeprom_write(USRP2_I2C_ADDR_MBOARD, USRP2_EE_MBOARD_IP_ADDR, t, sizeof(struct ip_addr));
-  if (ok){
-    src_ip_addr = *t;
-    src_ip_addr_initialized = true;
-  }
+    const bool ok = eeprom_write(USRP2_I2C_ADDR_MBOARD, USRP2_EE_MBOARD_IP_ADDR, t, sizeof(struct ip_addr));
+    if (ok) current_eth_addrs.ip_addr = *t;
+    return ok;
+}
 
-  return ok;
+void eth_addrs_set_default(void){
+    eth_addrs_initialized = true;
+    memcpy(&current_eth_addrs, &default_eth_addrs, sizeof(default_eth_addrs));
 }
diff --git a/firmware/zpu/lib/ethernet.h b/firmware/zpu/lib/ethernet.h
index 52b297349..b5b08cb8c 100644
--- a/firmware/zpu/lib/ethernet.h
+++ b/firmware/zpu/lib/ethernet.h
@@ -1,5 +1,5 @@
-/* -*- c -*- */
 /*
+ * Copyright 2010-2012 Ettus Research LLC
  * Copyright 2007 Free Software Foundation, Inc.
  *
  * This program is free software: you can redistribute it and/or modify
@@ -44,27 +44,28 @@ void ethernet_register_link_changed_callback(ethernet_link_changed_callback_t cb
  */
 const eth_mac_addr_t *ethernet_mac_addr(void);
 
-/*!set mac addr to default*/
-void set_default_mac_addr(void);
-
 /*!
- * \brief write mac address to eeprom and begin using it
+ * \returns IP address
  */
-bool ethernet_set_mac_addr(const eth_mac_addr_t *t);
+const struct ip_addr *get_ip_addr(void);
 
 /*!
- * \returns IP address
+ * \returns gateway address
  */
-const struct ip_addr *get_ip_addr(void);
+const struct ip_addr *get_gateway(void);
 
-/*!set ip addr to default*/
-void set_default_ip_addr(void);
+/*!
+ * \returns subnet address
+ */
+const struct ip_addr *get_subnet(void);
 
 /*!
  * \brief write ip address to eeprom and begin using it
  */
 bool set_ip_addr(const struct ip_addr *t);
 
+//! Apply default settings to eth addrs
+void eth_addrs_set_default(void);
 
 /*
  * \brief read RMON regs and return error mask
diff --git a/firmware/zpu/lib/net_common.c b/firmware/zpu/lib/net_common.c
index 42e365393..9b75006d3 100644
--- a/firmware/zpu/lib/net_common.c
+++ b/firmware/zpu/lib/net_common.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2009-2011 Ettus Research LLC
+ * Copyright 2009-2012 Ettus Research LLC
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -374,6 +374,22 @@ send_arp_reply(struct arp_eth_ipv4 *req, eth_mac_addr_t our_mac)
   send_pkt(t, ETHERTYPE_ARP, &reply, sizeof(reply), 0, 0, 0, 0);
 }
 
+void net_common_send_arp_request(const struct ip_addr *addr){
+    struct arp_eth_ipv4 req _AL4;
+    req.ar_hrd = ARPHRD_ETHER;
+    req.ar_pro = ETHERTYPE_IPV4;
+    req.ar_hln = sizeof(eth_mac_addr_t);
+    req.ar_pln = sizeof(struct ip_addr);
+    req.ar_op = ARPOP_REQUEST;
+    memcpy(req.ar_sha, ethernet_mac_addr(), sizeof(eth_mac_addr_t));
+    memcpy(req.ar_sip, get_ip_addr(), sizeof(struct ip_addr));
+    memset(req.ar_tha, 0x00, sizeof(eth_mac_addr_t));
+    memcpy(req.ar_tip, addr, sizeof(struct ip_addr));
+
+    //send the request with a broadcast ethernet mac address
+    send_pkt(BCAST_MAC_ADDR, ETHERTYPE_ARP, &req, sizeof(req), 0, 0, 0, 0);
+}
+
 void send_gratuitous_arp(void){
   struct arp_eth_ipv4 req _AL4;
   req.ar_hrd = ARPHRD_ETHER;
@@ -415,7 +431,15 @@ handle_arp_packet(struct arp_eth_ipv4 *p, size_t size)
       || p->ar_hln != 6
       || p->ar_pln != 4)
     return;
-  
+
+  if (p->ar_op == ARPOP_REPLY){
+    struct ip_addr ip_addr;
+    memcpy(&ip_addr, p->ar_sip, sizeof(ip_addr));
+    eth_mac_addr_t mac_addr;
+    memcpy(&mac_addr, p->ar_sha, sizeof(mac_addr));
+    arp_cache_update(&ip_addr, &mac_addr);
+  }
+
   if (p->ar_op != ARPOP_REQUEST)
     return;
 
diff --git a/firmware/zpu/lib/net_common.h b/firmware/zpu/lib/net_common.h
index 3cbc5c514..5e6daf689 100644
--- a/firmware/zpu/lib/net_common.h
+++ b/firmware/zpu/lib/net_common.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2009-2011 Ettus Research LLC
+ * Copyright 2009-2012 Ettus Research LLC
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -55,4 +55,7 @@ void handle_eth_packet(uint32_t *p, size_t nlines);
 
 void send_gratuitous_arp(void);
 
+//! Send an ARP request for the given IP address
+void net_common_send_arp_request(const struct ip_addr *addr);
+
 #endif /* INCLUDED_NET_COMMON_H */
diff --git a/firmware/zpu/usrp2p/u2p_init.c b/firmware/zpu/usrp2p/u2p_init.c
index 381987ae6..1890dd726 100644
--- a/firmware/zpu/usrp2p/u2p_init.c
+++ b/firmware/zpu/usrp2p/u2p_init.c
@@ -24,7 +24,6 @@ void u2p_init(void){
     bool safe_fw = find_safe_booted_flag();
     set_safe_booted_flag(0);
     if (safe_fw) {
-        set_default_ip_addr();
-        set_default_mac_addr();
+        eth_addrs_set_default();
     }
 }
diff --git a/host/docs/usrp2.rst b/host/docs/usrp2.rst
index d81440b07..bf42e70b9 100644
--- a/host/docs/usrp2.rst
+++ b/host/docs/usrp2.rst
@@ -315,6 +315,55 @@ the following clock configuration must be set on the slave device:
     clock_config.pps_source = uhd::clock_config_t::PPS_MIMO;
     usrp->set_clock_config(clock_config, slave_index);
 
+
+------------------------------------------------------------------------
+Alternative stream destination
+------------------------------------------------------------------------
+It is possible to program the USRP to send RX packets to an alternative IP/UDP destination.
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Set the subnet and gateway
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+To use an alternative streaming destination,
+the device needs to be able to determine if the destination address
+is within its subnet, and ARP appropriately.
+Therefore, the user should ensure that subnet and gateway addresses
+have been programmed into the device's EEPROM.
+
+Run the following commands:
+::
+
+    cd <install-path>/share/uhd/utils
+    ./usrp_burn_mb_eeprom --args=<optional device args> --key=subnet --val=255.255.255.0
+    ./usrp_burn_mb_eeprom --args=<optional device args> --key=gateway --val=192.168.10.1
+
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Create a receive streamer
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Set the stream args "addr" and "port" values to the alternative destination.
+Packets will be sent to this destination when the user issues a stream command.
+
+::
+
+    //create a receive streamer, host type does not matter
+    uhd::stream_args_t stream_args("fc32");
+
+    //resolvable address and port for a remote udp socket
+    stream_args.args["addr"] = "192.168.10.42";
+    stream_args.args["port"] = "12345";
+
+    //create the streamer
+    uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);
+
+    //issue stream command
+    uhd::stream_cmd_t stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE);
+    stream_cmd.num_samps = total_num_samps;
+    stream_cmd.stream_now = true;
+    usrp->issue_stream_cmd(stream_cmd);
+
+**Note:**
+Calling recv() on this streamer object should yield a timeout.
+
 ------------------------------------------------------------------------
 Hardware setup notes
 ------------------------------------------------------------------------
diff --git a/host/lib/usrp/mboard_eeprom.cpp b/host/lib/usrp/mboard_eeprom.cpp
index 785d30296..96a0d36ce 100644
--- a/host/lib/usrp/mboard_eeprom.cpp
+++ b/host/lib/usrp/mboard_eeprom.cpp
@@ -1,5 +1,5 @@
 //
-// Copyright 2010-2011 Ettus Research LLC
+// Copyright 2010-2012 Ettus Research LLC
 //
 // This program is free software: you can redistribute it and/or modify
 // it under the terms of the GNU General Public License as published by
@@ -84,17 +84,20 @@ static std::string uint16_bytes_to_string(const byte_vector_t &bytes){
  **********************************************************************/
 static const boost::uint8_t N100_EEPROM_ADDR = 0x50;
 
-static const uhd::dict<std::string, boost::uint8_t> USRP_N100_OFFSETS = boost::assign::map_list_of
-    ("hardware", 0x00)
-    ("mac-addr", 0x02)
-    ("ip-addr", 0x0C)
-    //leave space here for other addresses (perhaps)
-    ("revision", 0x12)
-    ("product", 0x14)
-    ("gpsdo", 0x17)
-    ("serial", 0x18)
-    ("name", 0x18 + SERIAL_LEN)
-;
+struct n100_eeprom_map{
+    boost::uint16_t hardware;
+    boost::uint8_t mac_addr[6];
+    boost::uint32_t subnet;
+    boost::uint32_t ip_addr;
+    boost::uint16_t _pad0;
+    boost::uint16_t revision;
+    boost::uint16_t product;
+    unsigned char _pad1;
+    unsigned char gpsdo;
+    unsigned char serial[SERIAL_LEN];
+    unsigned char name[NAME_MAX_LEN];
+    boost::uint32_t gateway;
+};
 
 enum n200_gpsdo_type{
     N200_GPSDO_NONE = 0,
@@ -105,30 +108,36 @@ enum n200_gpsdo_type{
 static void load_n100(mboard_eeprom_t &mb_eeprom, i2c_iface &iface){
     //extract the hardware number
     mb_eeprom["hardware"] = uint16_bytes_to_string(
-        iface.read_eeprom(N100_EEPROM_ADDR, USRP_N100_OFFSETS["hardware"], 2)
+        iface.read_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, hardware), 2)
     );
 
     //extract the revision number
     mb_eeprom["revision"] = uint16_bytes_to_string(
-        iface.read_eeprom(N100_EEPROM_ADDR, USRP_N100_OFFSETS["revision"], 2)
+        iface.read_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, revision), 2)
     );
 
     //extract the product code
     mb_eeprom["product"] = uint16_bytes_to_string(
-        iface.read_eeprom(N100_EEPROM_ADDR, USRP_N100_OFFSETS["product"], 2)
+        iface.read_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, product), 2)
     );
 
     //extract the addresses
     mb_eeprom["mac-addr"] = mac_addr_t::from_bytes(iface.read_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["mac-addr"], 6
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, mac_addr), 6
     )).to_string();
 
     boost::asio::ip::address_v4::bytes_type ip_addr_bytes;
-    byte_copy(iface.read_eeprom(N100_EEPROM_ADDR, USRP_N100_OFFSETS["ip-addr"], 4), ip_addr_bytes);
+    byte_copy(iface.read_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, ip_addr), 4), ip_addr_bytes);
     mb_eeprom["ip-addr"] = boost::asio::ip::address_v4(ip_addr_bytes).to_string();
 
+    byte_copy(iface.read_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, subnet), 4), ip_addr_bytes);
+    mb_eeprom["subnet"] = boost::asio::ip::address_v4(ip_addr_bytes).to_string();
+
+    byte_copy(iface.read_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, gateway), 4), ip_addr_bytes);
+    mb_eeprom["gateway"] = boost::asio::ip::address_v4(ip_addr_bytes).to_string();
+
     //gpsdo capabilities
-    boost::uint8_t gpsdo_byte = iface.read_eeprom(N100_EEPROM_ADDR, USRP_N100_OFFSETS["gpsdo"], 1).at(0);
+    boost::uint8_t gpsdo_byte = iface.read_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, gpsdo), 1).at(0);
     switch(n200_gpsdo_type(gpsdo_byte)){
     case N200_GPSDO_INTERNAL: mb_eeprom["gpsdo"] = "internal"; break;
     case N200_GPSDO_ONBOARD: mb_eeprom["gpsdo"] = "onboard"; break;
@@ -137,12 +146,12 @@ static void load_n100(mboard_eeprom_t &mb_eeprom, i2c_iface &iface){
 
     //extract the serial
     mb_eeprom["serial"] = bytes_to_string(iface.read_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["serial"], SERIAL_LEN
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, serial), SERIAL_LEN
     ));
 
     //extract the name
     mb_eeprom["name"] = bytes_to_string(iface.read_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["name"], NAME_MAX_LEN
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, name), NAME_MAX_LEN
     ));
 
     //Empty serial correction: use the mac address to determine serial.
@@ -158,32 +167,44 @@ static void load_n100(mboard_eeprom_t &mb_eeprom, i2c_iface &iface){
 static void store_n100(const mboard_eeprom_t &mb_eeprom, i2c_iface &iface){
     //parse the revision number
     if (mb_eeprom.has_key("hardware")) iface.write_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["hardware"],
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, hardware),
         string_to_uint16_bytes(mb_eeprom["hardware"])
     );
 
     //parse the revision number
     if (mb_eeprom.has_key("revision")) iface.write_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["revision"],
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, revision),
         string_to_uint16_bytes(mb_eeprom["revision"])
     );
 
     //parse the product code
     if (mb_eeprom.has_key("product")) iface.write_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["product"],
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, product),
         string_to_uint16_bytes(mb_eeprom["product"])
     );
 
     //store the addresses
     if (mb_eeprom.has_key("mac-addr")) iface.write_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["mac-addr"],
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, mac_addr),
         mac_addr_t::from_string(mb_eeprom["mac-addr"]).to_bytes()
     );
 
     if (mb_eeprom.has_key("ip-addr")){
         byte_vector_t ip_addr_bytes(4);
         byte_copy(boost::asio::ip::address_v4::from_string(mb_eeprom["ip-addr"]).to_bytes(), ip_addr_bytes);
-        iface.write_eeprom(N100_EEPROM_ADDR, USRP_N100_OFFSETS["ip-addr"], ip_addr_bytes);
+        iface.write_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, ip_addr), ip_addr_bytes);
+    }
+
+    if (mb_eeprom.has_key("subnet")){
+        byte_vector_t ip_addr_bytes(4);
+        byte_copy(boost::asio::ip::address_v4::from_string(mb_eeprom["subnet"]).to_bytes(), ip_addr_bytes);
+        iface.write_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, subnet), ip_addr_bytes);
+    }
+
+    if (mb_eeprom.has_key("gateway")){
+        byte_vector_t ip_addr_bytes(4);
+        byte_copy(boost::asio::ip::address_v4::from_string(mb_eeprom["gateway"]).to_bytes(), ip_addr_bytes);
+        iface.write_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, gateway), ip_addr_bytes);
     }
 
     //gpsdo capabilities
@@ -191,18 +212,18 @@ static void store_n100(const mboard_eeprom_t &mb_eeprom, i2c_iface &iface){
         boost::uint8_t gpsdo_byte = N200_GPSDO_NONE;
         if (mb_eeprom["gpsdo"] == "internal") gpsdo_byte = N200_GPSDO_INTERNAL;
         if (mb_eeprom["gpsdo"] == "onboard") gpsdo_byte = N200_GPSDO_ONBOARD;
-        iface.write_eeprom(N100_EEPROM_ADDR, USRP_N100_OFFSETS["gpsdo"], byte_vector_t(1, gpsdo_byte));
+        iface.write_eeprom(N100_EEPROM_ADDR, offsetof(n100_eeprom_map, gpsdo), byte_vector_t(1, gpsdo_byte));
     }
 
     //store the serial
     if (mb_eeprom.has_key("serial")) iface.write_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["serial"],
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, serial),
         string_to_bytes(mb_eeprom["serial"], SERIAL_LEN)
     );
 
     //store the name
     if (mb_eeprom.has_key("name")) iface.write_eeprom(
-        N100_EEPROM_ADDR, USRP_N100_OFFSETS["name"],
+        N100_EEPROM_ADDR, offsetof(n100_eeprom_map, name),
         string_to_bytes(mb_eeprom["name"], NAME_MAX_LEN)
     );
 }
diff --git a/host/lib/usrp/usrp2/fw_common.h b/host/lib/usrp/usrp2/fw_common.h
index 0babf7445..2add74c47 100644
--- a/host/lib/usrp/usrp2/fw_common.h
+++ b/host/lib/usrp/usrp2/fw_common.h
@@ -37,6 +37,13 @@ extern "C" {
 //used to differentiate control packets over data port
 #define USRP2_INVALID_VRT_HEADER 0
 
+typedef struct{
+    uint32_t sequence;
+    uint32_t vrt_hdr;
+    uint32_t ip_addr;
+    uint32_t udp_port;
+} usrp2_stream_ctrl_t;
+
 // udp ports for the usrp2 communication
 // Dynamic and/or private ports: 49152-65535
 #define USRP2_UDP_CTRL_PORT 49152
@@ -65,6 +72,8 @@ extern "C" {
 ////////////////////////////////////////////////////////////////////////
 #define USRP2_EE_MBOARD_REV      0x00 //2 bytes, little-endian (historic, don't blame me)
 #define USRP2_EE_MBOARD_MAC_ADDR 0x02 //6 bytes
+#define USRP2_EE_MBOARD_GATEWAY  0x38 //uint32, big-endian
+#define USRP2_EE_MBOARD_SUBNET   0x08 //uint32, big-endian
 #define USRP2_EE_MBOARD_IP_ADDR  0x0C //uint32, big-endian
 #define USRP2_EE_MBOARD_BOOTLOADER_FLAGS 0xF7
 
diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index d32ffb62c..ea4aa716c 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -21,6 +21,7 @@
 #include "../../transport/super_send_packet_handler.hpp"
 #include "usrp2_impl.hpp"
 #include "usrp2_regs.hpp"
+#include "fw_common.h"
 #include <uhd/utils/log.hpp>
 #include <uhd/utils/msg.hpp>
 #include <uhd/utils/tasks.hpp>
@@ -31,6 +32,7 @@
 #include <boost/thread/thread.hpp>
 #include <boost/format.hpp>
 #include <boost/bind.hpp>
+#include <boost/asio.hpp>
 #include <boost/thread/mutex.hpp>
 #include <boost/make_shared.hpp>
 #include <iostream>
@@ -361,6 +363,60 @@ bool usrp2_impl::recv_async_msg(
 }
 
 /***********************************************************************
+ * Stream destination programmer
+ **********************************************************************/
+void usrp2_impl::program_stream_dest(
+    zero_copy_if::sptr &xport, const uhd::stream_args_t &args
+){
+    //perform an initial flush of transport
+    while (xport->get_recv_buff(0.0)){}
+
+    //program the stream command
+    usrp2_stream_ctrl_t stream_ctrl = usrp2_stream_ctrl_t();
+    stream_ctrl.sequence = uhd::htonx(boost::uint32_t(0 /* don't care seq num */));
+    stream_ctrl.vrt_hdr = uhd::htonx(boost::uint32_t(USRP2_INVALID_VRT_HEADER));
+
+    //user has provided an alternative address and port for destination
+    if (args.args.has_key("addr") and args.args.has_key("port")){
+        UHD_MSG(status) << boost::format(
+            "Programming streaming destination for custom address.\n"
+            "IPv4 Address: %s, UDP Port: %s\n"
+        ) % args.args["addr"] % args.args["port"] << std::endl;
+
+        asio::io_service io_service;
+        asio::ip::udp::resolver resolver(io_service);
+        asio::ip::udp::resolver::query query(asio::ip::udp::v4(), args.args["addr"], args.args["port"]);
+        asio::ip::udp::endpoint endpoint = *resolver.resolve(query);
+        stream_ctrl.ip_addr = uhd::htonx(boost::uint32_t(endpoint.address().to_v4().to_ulong()));
+        stream_ctrl.udp_port = uhd::htonx(boost::uint32_t(endpoint.port()));
+
+        for (size_t i = 0; i < 3; i++){
+            UHD_MSG(status) << "ARP attempt " << i << std::endl;
+            managed_send_buffer::sptr send_buff = xport->get_send_buff();
+            std::memcpy(send_buff->cast<void *>(), &stream_ctrl, sizeof(stream_ctrl));
+            send_buff->commit(sizeof(stream_ctrl));
+            boost::this_thread::sleep(boost::posix_time::milliseconds(300));
+            managed_recv_buffer::sptr recv_buff = xport->get_recv_buff(0.0);
+            if (recv_buff and recv_buff->size() >= sizeof(boost::uint32_t)){
+                const boost::uint32_t result = uhd::ntohx(recv_buff->cast<const boost::uint32_t *>()[0]);
+                if (result == 0){
+                    UHD_MSG(status) << "Success! " << std::endl;
+                    return;
+                }
+            }
+        }
+        throw uhd::runtime_error("Device failed to ARP when programming alternative streaming destination.");
+    }
+
+    else{
+        //send the partial stream control without destination
+        managed_send_buffer::sptr send_buff = xport->get_send_buff();
+        std::memcpy(send_buff->cast<void *>(), &stream_ctrl, sizeof(stream_ctrl));
+        send_buff->commit(sizeof(stream_ctrl)/2);
+    }
+}
+
+/***********************************************************************
  * Receive streamer
  **********************************************************************/
 rx_streamer::sptr usrp2_impl::get_rx_stream(const uhd::stream_args_t &args_){
@@ -406,6 +462,7 @@ rx_streamer::sptr usrp2_impl::get_rx_stream(const uhd::stream_args_t &args_){
                 const size_t dsp = chan + _mbc[mb].rx_chan_occ - num_chan_so_far;
                 _mbc[mb].rx_dsps[dsp]->set_nsamps_per_packet(spp); //seems to be a good place to set this
                 _mbc[mb].rx_dsps[dsp]->setup(args);
+                this->program_stream_dest(_mbc[mb].rx_dsp_xports[dsp], args);
                 my_streamer->set_xport_chan_get_buff(chan_i, boost::bind(
                     &zero_copy_if::get_recv_buff, _mbc[mb].rx_dsp_xports[dsp], _1
                 ), true /*flush*/);
diff --git a/host/lib/usrp/usrp2/usrp2_impl.hpp b/host/lib/usrp/usrp2/usrp2_impl.hpp
index e5065c02d..6053c3890 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.hpp
@@ -129,6 +129,7 @@ private:
     double set_tx_dsp_freq(const std::string &, const double);
     uhd::meta_range_t get_tx_dsp_freq_range(const std::string &);
     void update_clock_source(const std::string &, const std::string &);
+    void program_stream_dest(uhd::transport::zero_copy_if::sptr &, const uhd::stream_args_t &);
 };
 
 #endif /* INCLUDED_USRP2_IMPL_HPP */