From 62a534ab629a8e685f63c7f40f66855440a1103c Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Wed, 4 Sep 2024 15:38:48 +1000
Subject: [PATCH 01/18] Fix inconsistensies with network components mk snippet

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 network/components/network_components.mk | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/network/components/network_components.mk b/network/components/network_components.mk
index 9ed9b3fd4..d681a79c7 100644
--- a/network/components/network_components.mk
+++ b/network/components/network_components.mk
@@ -11,7 +11,6 @@
 # Generates network_virt_rx.elf network_virt_tx.elf arp.elf copy.elf
 # Requires ${SDDF}/util/util.mk to build the utility library for debug output
 
-NETWORK_COMPONENTS_DIR := $(abspath $(dir $(lastword ${MAKEFILE_LIST})))
 NETWORK_IMAGES:= network_virt_rx.elf network_virt_tx.elf arp.elf copy.elf
 network/components/%.o: ${SDDF}/network/components/%.c
 	${CC} ${CFLAGS} -c -o $@ $<
@@ -40,10 +39,11 @@ network/components/network_virt_%.o: ${SDDF}/network/components/virt_%.c
 	${LD} ${LDFLAGS} -o $@ $< ${LIBS}
 
 clean::
-	rm -f network_virt_[rt]x.[od] copy.[od] arp.[od]
+	${RM} -f network_virt_[rt]x.[od] copy.[od] arp.[od]
 
 clobber::
-	rm -f ${IMAGES}
+	${RM} -f ${NETWORK_IMAGES}
+	rmdir network/components
 
 network/components:
 	mkdir -p $@

From f66940af221829c771edf50fe7fbb5253b7e9b69 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Wed, 4 Sep 2024 16:39:07 +1000
Subject: [PATCH 02/18] Create sDDF LWIP interface library

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 .../include/ethernet_config/ethernet_config.h |   1 +
 include/sddf/network/lib_sddf_lwip.h          | 111 ++++++
 include/sddf/network/util.h                   |   2 +-
 network/lib_sddf_lwip/lib_sddf_lwip.c         | 369 ++++++++++++++++++
 network/lib_sddf_lwip/lib_sddf_lwip.mk        |  32 ++
 5 files changed, 514 insertions(+), 1 deletion(-)
 create mode 100644 include/sddf/network/lib_sddf_lwip.h
 create mode 100644 network/lib_sddf_lwip/lib_sddf_lwip.c
 create mode 100644 network/lib_sddf_lwip/lib_sddf_lwip.mk

diff --git a/examples/echo_server/include/ethernet_config/ethernet_config.h b/examples/echo_server/include/ethernet_config/ethernet_config.h
index 2d810c381..7a5913a80 100644
--- a/examples/echo_server/include/ethernet_config/ethernet_config.h
+++ b/examples/echo_server/include/ethernet_config/ethernet_config.h
@@ -8,6 +8,7 @@
 #include <microkit.h>
 #include <sddf/util/string.h>
 #include <sddf/network/queue.h>
+#include <sddf/network/util.h>
 #include <sddf/util/util.h>
 
 #define NUM_NETWORK_CLIENTS 2
diff --git a/include/sddf/network/lib_sddf_lwip.h b/include/sddf/network/lib_sddf_lwip.h
new file mode 100644
index 000000000..ac8c668a0
--- /dev/null
+++ b/include/sddf/network/lib_sddf_lwip.h
@@ -0,0 +1,111 @@
+/*
+ * Copyright 2022, UNSW
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <microkit.h>
+#include <sddf/network/queue.h>
+#include "lwip/pbuf.h"
+
+#define LINK_SPEED 1000000000 // Gigabit
+#define ETHER_MTU 1500
+
+/* Definitions for sDDF error constants. */
+typedef enum {
+    /* No error, everything OK. */
+    SDDF_ERR_OK = 0,
+    /* Pbuf too large for sDDF buffer. */
+    SDDF_ERR_PBUF = -1,
+    /* No buffers available. */
+    SDDF_ERR_NO_BUF = -2,
+    /* Pbuf successfully enqueued to be sent later. */
+    SDDF_ERR_ENQUEUED    = -3,
+    /* Could not resolve error. */
+    SDDF_ERR_UNHANDLED    = -4
+} net_sddf_err_t;
+
+/**
+ * Function type for output of sDDF LWIP errors.
+ */
+typedef int (*sddf_lwip_err_output_fn)(const char *format, ...);
+
+/**
+ * Function type for netif status callback. Invoked by LWIP upon
+ * successfully obtaining an IP address for the network interface.
+ */
+typedef void (*sddf_lwip_netif_status_callback_fn)(char *ip_addr);
+
+/**
+ * Function type for handling function which is optionally invoked
+ * when a pbuf is unable to be sent due to no available sDDF tx buffers.
+ * Can be used to store pbuf until more buffers are available.
+ */
+typedef net_sddf_err_t (*sddf_lwip_handle_empty_tx_free_fn)(struct pbuf *p);
+
+/** 
+ * Checks LWIP system timeouts. Should be invoked after every LWIP tick.
+ */
+void sddf_lwip_process_timeout(void);
+
+/**
+ * Transmits the provided pbuf through the sddf network system.
+ *
+ * @param p pbuf to be transmitted.
+ *
+ * @return If the pbuf is sent successfully, SDDF_ERR_OK is returned and the
+ * pbuf can safely be freed. If the pbuf is too large, SDDF_ERR_PBUF is
+ * returned. If there are no free sDDF buffers available,
+ * handle_empty_tx_free will be called with the pbuf, and the return value
+ * will be returned.
+ */
+net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p);
+
+/** 
+ * Handles the passing of incoming packets in sDDF buffers to LWIP. Must be
+ * called to process the sDDF RX queue each time a notification is received
+ * from the network virtualiser.
+ */
+void sddf_lwip_process_rx(void);
+
+/**
+ * Handles the sending of notifications to the network RX and TX virtualisers.
+ * Must be invoked at the end of each event handling loop to ensure outgoing
+ * buffers are processed by the virtualisers.
+ */
+void sddf_lwip_maybe_notify(void);
+
+/**
+ * Initialisation function for the sDDF LWIP library. Must be called prior
+ * to using any other library functions.
+ *
+ * @param rx_queue RX net queue handle data structure. Must be initialised
+ * prior to being passed to this function.
+ * @param tx_queue TX net queue handle data structure. Must be initialised
+ * prior to being passed to this function.
+ * @param rx_ch RX notification channel to the net RX virtualiser.
+ * @param tx_ch TX notification channel to the net TX virtualiser.
+ * @param rx_buffer_data_region virtual address of the start of the RX
+ * buffer region.
+ * @param tx_buffer_data_region virtual address of the start of the TX
+ * buffer region.
+ * @param timer_ch timer notification channel to the timer driver.
+ * @param mac mac address of the client.
+ * @param err_output function pointer to optional user provided error
+ * output function. Provide NULL to use default sddf_printf_.
+ * @param netif_callback function pointer to optional user provided netif
+ * status callback function. Provide NULL to use err_output to print client
+ * MAC address and obtained IP address.
+ * @param handle_empty_tx_free function pointer to optional user provided
+ * handling function for no available sDDF TX buffers during sending of LWIP
+ * pbuf. Provide NULL to leave unhandled.
+ */
+void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
+                    microkit_channel rx_ch, microkit_channel tx_ch,
+                    uintptr_t rx_buffer_data_region,
+                    uintptr_t tx_buffer_data_region,
+                    microkit_channel timer_ch,
+                    uint64_t mac, sddf_lwip_err_output_fn err_output,
+                    sddf_lwip_netif_status_callback_fn netif_callback,
+                    sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free);
\ No newline at end of file
diff --git a/include/sddf/network/util.h b/include/sddf/network/util.h
index 916a56322..1c45f8d33 100644
--- a/include/sddf/network/util.h
+++ b/include/sddf/network/util.h
@@ -21,4 +21,4 @@ static void net_set_mac_addr(uint8_t *mac, uint64_t val)
     mac[3] = val >> 16 & 0xff;
     mac[4] = val >> 8 & 0xff;
     mac[5] = val & 0xff;
-}
\ No newline at end of file
+}
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
new file mode 100644
index 000000000..94ff95542
--- /dev/null
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -0,0 +1,369 @@
+/*
+ * Copyright 2022, UNSW
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <microkit.h>
+#include <sddf/util/util.h>
+#include <sddf/util/printf.h>
+#include <sddf/util/string.h>
+#include <sddf/network/lib_sddf_lwip.h>
+#include <sddf/network/queue.h>
+#include <sddf/network/util.h>
+#include <sddf/timer/client.h>
+#include "lwip/err.h"
+#include "lwip/init.h"
+#include "lwip/ip4_addr.h"
+#include "netif/etharp.h"
+#include "lwip/pbuf.h"
+#include "lwip/netif.h"
+#include "lwip/snmp.h"
+#include "lwip/sys.h"
+#include "lwip/timeouts.h"
+#include "lwip/dhcp.h"
+
+typedef struct lwip_state {
+    /* LWIP network interface struct. */
+    struct netif netif;
+    /* MAC address of client. */
+    uint64_t mac;
+    /* Output function used to print error messages. */
+    sddf_lwip_err_output_fn err_output;
+    /* Callback function to be invoked when ip address is obtained. */
+    sddf_lwip_netif_status_callback_fn netif_callback;
+    /* Function that optionally handles when no free tx buffers available. */
+    sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free;
+} lwip_state_t;
+
+typedef struct sddf_state {
+    /* sddf net rx queue handle. */
+    net_queue_handle_t rx_queue;
+    /* sddf net tx queue handle. */
+    net_queue_handle_t tx_queue;
+    /* sddf channel for net rx virt. */
+    microkit_channel rx_ch;
+    /* sddf channel for net tx virt. */
+    microkit_channel tx_ch;
+    /* Base address of data region containing rx buffers. */
+    uintptr_t rx_buffer_data_region;
+    /* Base address of data region containing tx buffers. */
+    uintptr_t tx_buffer_data_region;
+    /* Boolean indicating whether buffers have been given to rx virt. */
+    bool notify_rx;
+    /* Boolean indicating whether buffers have been given to tx virt. */
+    bool notify_tx;
+    /* sddf channel for timer. */
+    microkit_channel timer_ch;
+} sddf_state_t;
+
+/* Wrapper over custom_pbuf structure to keep track of buffer's offset into data region. */
+typedef struct pbuf_custom_offset {
+    struct pbuf_custom custom;
+    uint64_t offset;
+} pbuf_custom_offset_t;
+
+LWIP_MEMPOOL_DECLARE(
+    RX_POOL,
+    MAX_NUM_BUFFS * 2,
+    sizeof(struct pbuf_custom_offset),
+    "Zero-copy RX pool"
+);
+
+lwip_state_t lwip_state;
+sddf_state_t sddf_state;
+
+/**
+ * Helper function to convert sddf errors to lwip errors.
+ * 
+ * @param sddf_err sddf error.
+ *
+ * @return Equivalent lwip error. 
+ */
+static err_t sddf_err_to_lwip_err(net_sddf_err_t sddf_err) {
+    switch (sddf_err) {
+        case SDDF_ERR_OK:
+            return ERR_OK;
+        case SDDF_ERR_PBUF:
+            return ERR_BUF;
+        case SDDF_ERR_NO_BUF:
+            return ERR_MEM;
+        case SDDF_ERR_ENQUEUED:
+            return ERR_OK;
+        case SDDF_ERR_UNHANDLED:
+            return ERR_MEM;
+    }
+    return ERR_ARG;
+}
+
+/**
+ * Default netif status callback function. Prints client MAC address and
+ * obtained ip address.
+ * 
+ * @param ip_addr Obtained ip address as a string. 
+ */
+static void netif_status_callback_default(char *ip_addr) {
+    uint8_t *mac = lwip_state.netif.hwaddr;
+    lwip_state.err_output("LWIP|NOTICE: DHCP request for mac "
+                       "%02lx:%02lx:%02lx:%02lx:%02lx:%02lx "
+                       "returned ip address: %s\n", mac[0],
+                       mac[1], mac[2], mac[3], mac[4], mac[5],
+                       ip_addr);
+}
+
+/**
+ * Default handling function to be called during transmission if tx free
+ * queue is empty.
+ * 
+ * @param p pbuf that could not be sent due to queue being empty.
+ *
+ * @return Simply returns the sddf error indicating nothing was done.
+ */
+static net_sddf_err_t handle_empty_tx_free_default(struct pbuf *p) {
+    return SDDF_ERR_UNHANDLED;
+}
+
+/**
+ * Returns current time from the timer.
+ */
+uint32_t sys_now(void) {
+    return sddf_timer_time_now(sddf_state.timer_ch) / NS_IN_MS;
+}
+
+void sddf_lwip_process_timeout() {
+    sys_check_timeouts();
+}
+
+/**
+ * Free a pbuf. This also returns the underlying sddf buffer to the receive free ring.
+ *
+ * @param p pbuf to free.
+ */
+static void interface_free_buffer(struct pbuf *p) {
+    SYS_ARCH_DECL_PROTECT(old_level);
+    pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *)p;
+    SYS_ARCH_PROTECT(old_level);
+    net_buff_desc_t buffer = {custom_pbuf_offset->offset, 0};
+    int err = net_enqueue_free(&(sddf_state.rx_queue), buffer);
+    assert(!err);
+    sddf_state.notify_rx = true;
+    LWIP_MEMPOOL_FREE(RX_POOL, custom_pbuf_offset);
+    SYS_ARCH_UNPROTECT(old_level);
+}
+
+/**
+ * Create a pbuf structure to pass to the network interface.
+ *
+ * @param offset offset into the data region of the buffer to be passed.
+ * @param length length of data.
+ *
+ * @return the newly created pbuf. Can be cast to pbuf_custom.
+ */
+static struct pbuf *create_interface_buffer(uint64_t offset, size_t length) {
+    pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *) LWIP_MEMPOOL_ALLOC(RX_POOL);
+    custom_pbuf_offset->offset = offset;
+    custom_pbuf_offset->custom.custom_free_function = interface_free_buffer;
+
+    return pbuf_alloced_custom(
+               PBUF_RAW,
+               length,
+               PBUF_REF,
+               &custom_pbuf_offset->custom,
+               (void *)(offset + sddf_state.rx_buffer_data_region),
+               NET_BUFFER_SIZE
+           );
+}
+
+/**
+ * Copy a pbuf into an sddf buffer and insert it into the transmit active queue.
+ *
+ * @param netif lwip network interface state.
+ * @param p pbuf to be transmitted.
+ *
+ * @return If the pbuf is sent, ERR_OK is returned and the pbuf can safely be
+ * freed. If the pbuf is too large ERR_MEM is returned. If there are no free
+ * sddf buffers available, handle_empty_tx_free will be called with the pbuf,
+ * and the equivalent lwip error will be returned.
+ */
+static err_t lwip_eth_send(struct netif *netif, struct pbuf *p) {
+    if (p->tot_len > NET_BUFFER_SIZE) {
+        lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
+                              p->tot_len, NET_BUFFER_SIZE);
+        return ERR_MEM;
+    }
+
+    if (net_queue_empty_free(&sddf_state.tx_queue)) {
+        return sddf_err_to_lwip_err(lwip_state.handle_empty_tx_free(p));
+    }
+
+    net_buff_desc_t buffer;
+    int err = net_dequeue_free(&sddf_state.tx_queue, &buffer);
+    assert(!err);
+
+    uintptr_t frame = buffer.io_or_offset + sddf_state.tx_buffer_data_region;
+    uint16_t copied = 0;
+    for (struct pbuf *curr = p; curr != NULL; curr = curr->next) {
+        memcpy((void *)(frame + copied), curr->payload, curr->len);
+        copied += curr->len;
+    }
+
+    buffer.len = copied;
+    err = net_enqueue_active(&sddf_state.tx_queue, buffer);
+    assert(!err);
+
+    sddf_state.notify_tx = true;
+
+    return ERR_OK;
+}
+
+net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p) {
+    if (p->tot_len > NET_BUFFER_SIZE) {
+        lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
+                              p->tot_len, NET_BUFFER_SIZE);
+        return SDDF_ERR_PBUF;
+    }
+
+    if (net_queue_empty_free(&sddf_state.tx_queue)) {
+        return lwip_state.handle_empty_tx_free(p);
+    }
+
+    err_t err = lwip_eth_send(&lwip_state.netif, p);
+    assert(!err);
+
+    return SDDF_ERR_OK;
+}
+
+void sddf_lwip_process_rx(void) {
+    bool reprocess = true;
+    while (reprocess) {
+        while (!net_queue_empty_active(&sddf_state.rx_queue)) {
+            net_buff_desc_t buffer;
+            int err = net_dequeue_active(&sddf_state.rx_queue, &buffer);
+            assert(!err);
+
+            struct pbuf *p = create_interface_buffer(buffer.io_or_offset, buffer.len);
+            assert(p != NULL);
+            if (lwip_state.netif.input(p, &lwip_state.netif) != ERR_OK) {
+                lwip_state.err_output("LWIP|ERROR: unkown error inputting pbuf into network stack\n");
+                pbuf_free(p);
+            }
+        }
+
+        net_request_signal_active(&sddf_state.rx_queue);
+        reprocess = false;
+
+        if (!net_queue_empty_active(&sddf_state.rx_queue)) {
+            net_cancel_signal_active(&sddf_state.rx_queue);
+            reprocess = true;
+        }
+    }
+}
+
+/**
+ * Initialise the network interface data structure.
+ *
+ * @param netif network interface data structure.
+ */
+static err_t ethernet_init(struct netif *netif) {
+    if (netif->state == NULL) {
+        return ERR_ARG;
+    }
+    
+    net_set_mac_addr(netif->hwaddr, lwip_state.mac);
+    netif->mtu = ETHER_MTU;
+    netif->hwaddr_len = ETHARP_HWADDR_LEN;
+    netif->output = etharp_output;
+    netif->linkoutput = lwip_eth_send;
+    NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED);
+    netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP | NETIF_FLAG_IGMP;
+
+    return ERR_OK;
+}
+
+/**
+ * Network interface callback function invoked when DHCP packets are received.
+ * If an ip address is successfully obtained, the provided netif_callback
+ * function will be invoked with the ip address as a string.
+ *
+ * @param netif network interface data structure.
+ */
+static void netif_status_callback(struct netif *netif) {
+    if (dhcp_supplied_address(netif)) {
+        char ip4_str[IP4ADDR_STRLEN_MAX];
+        lwip_state.netif_callback(ip4addr_ntoa_r(netif_ip4_addr(netif), ip4_str, IP4ADDR_STRLEN_MAX));
+    }
+}
+
+void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
+                    microkit_channel rx_ch, microkit_channel tx_ch,
+                    uintptr_t rx_buffer_data_region,
+                    uintptr_t tx_buffer_data_region,
+                    microkit_channel timer_ch,
+                    uint64_t mac, sddf_lwip_err_output_fn err_output,
+                    sddf_lwip_netif_status_callback_fn netif_callback,
+                    sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free) {
+    /* Initialise sddf state */
+    sddf_state.rx_queue = rx_queue;
+    sddf_state.tx_queue = tx_queue;
+    sddf_state.rx_ch = rx_ch;
+    sddf_state.tx_ch = tx_ch;
+    sddf_state.rx_buffer_data_region = rx_buffer_data_region;
+    sddf_state.tx_buffer_data_region = tx_buffer_data_region;
+    sddf_state.timer_ch = timer_ch;
+
+    /* Initialise lwip state */
+    lwip_state.mac = mac;
+    lwip_state.err_output = (err_output == NULL)? sddf_printf_: err_output;
+    lwip_state.netif_callback = (netif_callback == NULL)? netif_status_callback_default: netif_callback;
+    lwip_state.handle_empty_tx_free = (handle_empty_tx_free == NULL)? handle_empty_tx_free_default: handle_empty_tx_free;
+
+    lwip_init();
+
+    LWIP_MEMPOOL_INIT(RX_POOL);
+
+    /* Set dummy IP configuration values to get lwIP bootstrapped */
+    struct ip4_addr netmask, ipaddr, gw, multicast;
+    ipaddr_aton("0.0.0.0", &gw);
+    ipaddr_aton("0.0.0.0", &ipaddr);
+    ipaddr_aton("0.0.0.0", &multicast);
+    ipaddr_aton("255.255.255.0", &netmask);
+
+    lwip_state.netif.name[0] = 'e';
+    lwip_state.netif.name[1] = '0';
+
+    if (!netif_add(&(lwip_state.netif), &ipaddr, &netmask, &gw, (void *)&lwip_state,
+                   ethernet_init, ethernet_input)) {
+        lwip_state.err_output("LWIP|ERROR: Netif add returned NULL\n");
+    }
+
+    netif_set_default(&(lwip_state.netif));
+    netif_set_status_callback(&(lwip_state.netif), netif_status_callback);
+    netif_set_up(&(lwip_state.netif));
+
+    if (dhcp_start(&(lwip_state.netif))) {
+        lwip_state.err_output("LWIP|ERROR: failed to start DHCP negotiation\n");
+    }
+}
+
+void sddf_lwip_maybe_notify() {
+    if (sddf_state.notify_rx && net_require_signal_free(&sddf_state.rx_queue)) {
+        net_cancel_signal_free(&sddf_state.rx_queue);
+        sddf_state.notify_rx = false;
+        if (!microkit_have_signal) {
+            microkit_deferred_notify(sddf_state.rx_ch);
+        } else if (microkit_signal_cap != BASE_OUTPUT_NOTIFICATION_CAP + sddf_state.rx_ch) {
+            microkit_notify(sddf_state.rx_ch);
+        }
+    }
+
+    if (sddf_state.notify_tx && net_require_signal_active(&sddf_state.tx_queue)) {
+        net_cancel_signal_active(&sddf_state.tx_queue);
+        sddf_state.notify_tx = false;
+        if (!microkit_have_signal) {
+            microkit_deferred_notify(sddf_state.tx_ch);
+        } else if (microkit_signal_cap != BASE_OUTPUT_NOTIFICATION_CAP + sddf_state.tx_ch) {
+            microkit_notify(sddf_state.tx_ch);
+        }
+    }
+}
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.mk b/network/lib_sddf_lwip/lib_sddf_lwip.mk
new file mode 100644
index 000000000..7f80c39bc
--- /dev/null
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.mk
@@ -0,0 +1,32 @@
+#
+# Copyright 2022, UNSW
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+
+ifeq ($(strip $(MAX_NUM_BUFFS)),)
+$(error MAX_NUM_BUFFS must be specified)
+endif
+
+CFLAGS += -DMAX_NUM_BUFFS=$(MAX_NUM_BUFFS)
+
+LIB_SDDF_LWIP_DIR := network/lib_sddf_lwip
+LIB_SDDF_LWIP_FILES := $(addprefix ${LIB_SDDF_LWIP_DIR}/, lib_sddf_lwip.c)
+LIB_SDDF_LWIP_OBJS := $(LIB_SDDF_LWIP_FILES:.c=.o)
+
+${LIB_SDDF_LWIP_OBJS}: | ${LIB_SDDF_LWIP_DIR} ${CHECK_FLAGS_BOARD_MD5}
+${LIB_SDDF_LWIP_DIR}:
+	mkdir -p $@
+
+lib_sddf_lwip.a: ${LIB_SDDF_LWIP_OBJS}
+	${AR} rv $@ $^
+	${RANLIB} $@
+
+clean::
+	${RM} -f ${LIB_SDDF_LWIP_OBJS} ${LIB_SDDF_LWIP_OBJS:.o=.d}
+
+clobber:: clean
+	${RM} -f lib_sddf_lwip.a
+	rmdir ${LIB_SDDF_LWIP_DIR}
+
+-include ${LIB_SDDF_LWIP_OBJS:.o=.d}

From c4646bf741897bced5950b1a3b17d7de5eecbcec Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Wed, 4 Sep 2024 17:29:58 +1000
Subject: [PATCH 03/18] Convert echo servers to use lib sddf_lwip

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 .../board/imx8mm_evk/echo_server.system       |   4 +-
 .../board/maaxboard/echo_server.system        |   4 +-
 .../board/odroidc4/echo_server.system         |   4 +-
 .../qemu_virt_aarch64/echo_server.system      |   4 +-
 examples/echo_server/echo.c                   | 165 ++++++++
 examples/echo_server/echo.h                   |   3 -
 examples/echo_server/echo.mk                  |  33 +-
 examples/echo_server/lwip.c                   | 395 ------------------
 8 files changed, 190 insertions(+), 422 deletions(-)
 create mode 100644 examples/echo_server/echo.c
 delete mode 100644 examples/echo_server/lwip.c

diff --git a/examples/echo_server/board/imx8mm_evk/echo_server.system b/examples/echo_server/board/imx8mm_evk/echo_server.system
index 264e4e867..f4c9dd681 100644
--- a/examples/echo_server/board/imx8mm_evk/echo_server.system
+++ b/examples/echo_server/board/imx8mm_evk/echo_server.system
@@ -164,7 +164,7 @@
         </protection_domain>
 
         <protection_domain name="client0" priority="97" budget="20000" id="6">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli0" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli0" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
@@ -181,7 +181,7 @@
         </protection_domain>
 
         <protection_domain name="client1" priority="95" budget="20000" id="7">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli1" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli1" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
diff --git a/examples/echo_server/board/maaxboard/echo_server.system b/examples/echo_server/board/maaxboard/echo_server.system
index 05e1d7684..a26891f98 100644
--- a/examples/echo_server/board/maaxboard/echo_server.system
+++ b/examples/echo_server/board/maaxboard/echo_server.system
@@ -164,7 +164,7 @@
         </protection_domain>
 
         <protection_domain name="client0" priority="97" budget="20000" id="6">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli0" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli0" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
@@ -181,7 +181,7 @@
         </protection_domain>
 
         <protection_domain name="client1" priority="95" budget="20000" id="7">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli1" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli1" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
diff --git a/examples/echo_server/board/odroidc4/echo_server.system b/examples/echo_server/board/odroidc4/echo_server.system
index 74998d981..001b4f9c8 100644
--- a/examples/echo_server/board/odroidc4/echo_server.system
+++ b/examples/echo_server/board/odroidc4/echo_server.system
@@ -164,7 +164,7 @@
         </protection_domain>
 
         <protection_domain name="client0" priority="97" budget="20000" id="6">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli0" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli0" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
@@ -181,7 +181,7 @@
         </protection_domain>
 
         <protection_domain name="client1" priority="95" budget="20000" id="7">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli1" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli1" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
diff --git a/examples/echo_server/board/qemu_virt_aarch64/echo_server.system b/examples/echo_server/board/qemu_virt_aarch64/echo_server.system
index 1cacbb3c9..8a859f46a 100644
--- a/examples/echo_server/board/qemu_virt_aarch64/echo_server.system
+++ b/examples/echo_server/board/qemu_virt_aarch64/echo_server.system
@@ -163,7 +163,7 @@
         </protection_domain>
 
         <protection_domain name="client0" priority="97" budget="20000" id="6">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli0" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli0" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
@@ -180,7 +180,7 @@
         </protection_domain>
 
         <protection_domain name="client1" priority="95" budget="20000" id="7">
-            <program_image path="lwip.elf" />
+            <program_image path="echo.elf" />
 
             <map mr="net_rx_free_cli1" vaddr="0x2_000_000" perms="rw" cached="true" setvar_vaddr="rx_free" />
             <map mr="net_rx_active_cli1" vaddr="0x2_200_000" perms="rw" cached="true" setvar_vaddr="rx_active" />
diff --git a/examples/echo_server/echo.c b/examples/echo_server/echo.c
new file mode 100644
index 000000000..f53d3d265
--- /dev/null
+++ b/examples/echo_server/echo.c
@@ -0,0 +1,165 @@
+/*
+ * Copyright 2022, UNSW
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include <stdbool.h>
+#include <stdint.h>
+#include <microkit.h>
+#include <sddf/util/util.h>
+#include <sddf/util/string.h>
+#include <sddf/util/printf.h>
+#include <sddf/network/lib_sddf_lwip.h>
+#include <sddf/network/queue.h>
+#include <sddf/serial/queue.h>
+#include <sddf/timer/client.h>
+#include <sddf/benchmark/sel4bench.h>
+#include <serial_config.h>
+#include <ethernet_config.h>
+#include "lwip/pbuf.h"
+
+#include "echo.h"
+
+#define SERIAL_TX_CH 0
+#define TIMER  1
+#define RX_CH  2
+#define TX_CH  3
+
+char *serial_tx_data;
+serial_queue_t *serial_tx_queue;
+serial_queue_handle_t serial_tx_queue_handle;
+
+net_queue_t *rx_free;
+net_queue_t *rx_active;
+net_queue_t *tx_free;
+net_queue_t *tx_active;
+uintptr_t rx_buffer_data_region;
+uintptr_t tx_buffer_data_region;
+
+net_queue_handle_t net_rx_handle;
+net_queue_handle_t net_tx_handle;
+
+#define LWIP_TICK_MS 100
+
+struct pbuf *head;
+struct pbuf *tail;
+
+/**
+ * Netif status callback function that output's client's Microkit name and
+ * obtained IP address.
+ * 
+ * @param ip_addr ip address of the client.
+ */
+void netif_status_callback(char *ip_addr) {
+    sddf_printf("DHCP request finished, IP address for netif %s is: %s\n", microkit_name, ip_addr);
+}
+
+/**
+ * Sets a timeout for the next lwip tick.
+ */
+void set_timeout(void) {
+    sddf_timer_set_timeout(TIMER, LWIP_TICK_MS * NS_IN_MS);
+}
+
+/**
+ * Stores a pbuf to be transmitted upon available transmit buffers.
+ *
+ * @param p pbuf to be stored.
+ */
+net_sddf_err_t enqueue_pbufs(struct pbuf *p)
+{
+    /* Indicate to the tx virt that we wish to be notified about free tx buffers */
+    net_request_signal_free(&net_tx_handle);
+
+    if (head == NULL) {
+        head = p;
+    } else {
+        tail->next_chain = p;
+    }
+    tail = p;
+
+    /* Increment reference count to ensure this pbuf is not freed by lwip */
+    pbuf_ref(p);
+
+    return SDDF_ERR_OK;
+}
+
+void transmit(void)
+{
+    bool reprocess = true;
+    while (reprocess) {
+        while (head != NULL && !net_queue_empty_free(&net_tx_handle)) {
+            net_sddf_err_t err = sddf_lwip_transmit_pbuf(head);
+            if (err == SDDF_ERR_PBUF) {
+                sddf_dprintf("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
+                             head->tot_len, NET_BUFFER_SIZE);
+            } else if (err != SDDF_ERR_OK) {
+                sddf_dprintf("LWIP|ERROR: unkown error when trying to send pbuf %p\n", head);
+            }
+
+            struct pbuf *temp = head;
+            head = temp->next_chain;
+            if (head == NULL) {
+                tail = NULL;
+            }
+            pbuf_free(temp);
+        }
+
+        /* Only request a signal if there are more pending pbufs to send */
+        if (head == NULL || !net_queue_empty_free(&net_tx_handle)) {
+            net_cancel_signal_free(&net_tx_handle);
+        } else {
+            net_request_signal_free(&net_tx_handle);
+        }
+        reprocess = false;
+
+        if (head != NULL && !net_queue_empty_free(&net_tx_handle)) {
+            net_cancel_signal_free(&net_tx_handle);
+            reprocess = true;
+        }
+    }
+}
+
+void init(void)
+{
+    serial_cli_queue_init_sys(microkit_name, NULL, NULL, NULL, &serial_tx_queue_handle, serial_tx_queue, serial_tx_data);
+    serial_putchar_init(SERIAL_TX_CH, &serial_tx_queue_handle);
+
+    size_t rx_size, tx_size;
+    net_cli_queue_size(microkit_name, &rx_size, &tx_size);
+    net_queue_init(&net_rx_handle, rx_free, rx_active, rx_size);
+    net_queue_init(&net_tx_handle, tx_free, tx_active, tx_size);
+    net_buffers_init(&net_tx_handle, 0);
+
+    sddf_lwip_init(net_rx_handle, net_tx_handle, RX_CH, TX_CH, rx_buffer_data_region, tx_buffer_data_region, TIMER,
+                   net_cli_mac_addr(microkit_name), NULL, netif_status_callback, enqueue_pbufs);
+    set_timeout();
+
+    setup_udp_socket();
+    setup_utilization_socket();
+    setup_tcp_socket();
+
+    sddf_lwip_maybe_notify();
+}
+
+void notified(microkit_channel ch)
+{
+    switch (ch) {
+    case RX_CH:
+        sddf_lwip_process_rx();
+        break;
+    case TIMER:
+        sddf_lwip_process_timeout();
+        set_timeout();
+        break;
+    case TX_CH:
+        transmit();
+        break;
+    case SERIAL_TX_CH:
+        break;
+    default:
+        sddf_dprintf("LWIP|LOG: received notification on unexpected channel: %u\n", ch);
+        break;
+    }
+
+    sddf_lwip_maybe_notify();
+}
diff --git a/examples/echo_server/echo.h b/examples/echo_server/echo.h
index f514c979c..066e22365 100644
--- a/examples/echo_server/echo.h
+++ b/examples/echo_server/echo.h
@@ -9,9 +9,6 @@
 #define UTILIZATION_PORT 1236
 #define TCP_ECHO_PORT 1237
 
-#define LINK_SPEED 1000000000 // Gigabit
-#define ETHER_MTU 1500
-
 int setup_udp_socket(void);
 int setup_utilization_socket(void);
 int setup_tcp_socket(void);
diff --git a/examples/echo_server/echo.mk b/examples/echo_server/echo.mk
index bf5e3a67c..0434cf57a 100644
--- a/examples/echo_server/echo.mk
+++ b/examples/echo_server/echo.mk
@@ -7,17 +7,17 @@
 QEMU := qemu-system-aarch64
 
 MICROKIT_TOOL ?= $(MICROKIT_SDK)/bin/microkit
-ECHO_SERVER:=${SDDF}/examples/echo_server
-LWIPDIR:=network/ipstacks/lwip/src
-BENCHMARK:=$(SDDF)/benchmark
-UTIL:=$(SDDF)/util
-ETHERNET_DRIVER:=$(SDDF)/drivers/network/$(DRIV_DIR)
-ETHERNET_CONFIG_INCLUDE:=${ECHO_SERVER}/include/ethernet_config
+ECHO_SERVER := ${SDDF}/examples/echo_server
+LWIPDIR := network/ipstacks/lwip/src
+BENCHMARK := $(SDDF)/benchmark
+UTIL := $(SDDF)/util
+ETHERNET_DRIVER := $(SDDF)/drivers/network/$(DRIV_DIR)
+ETHERNET_CONFIG_INCLUDE := ${ECHO_SERVER}/include/ethernet_config
 SERIAL_COMPONENTS := $(SDDF)/serial/components
 UART_DRIVER := $(SDDF)/drivers/serial/$(UART_DRIV_DIR)
-SERIAL_CONFIG_INCLUDE:=${ECHO_SERVER}/include/serial_config
+SERIAL_CONFIG_INCLUDE := ${ECHO_SERVER}/include/serial_config
 TIMER_DRIVER:=$(SDDF)/drivers/timer/$(TIMER_DRV_DIR)
-NETWORK_COMPONENTS:=$(SDDF)/network/components
+NETWORK_COMPONENTS := $(SDDF)/network/components
 
 BOARD_DIR := $(MICROKIT_SDK)/board/$(MICROKIT_BOARD)/$(MICROKIT_CONFIG)
 SYSTEM_FILE := ${ECHO_SERVER}/board/$(MICROKIT_BOARD)/echo_server.system
@@ -26,7 +26,7 @@ REPORT_FILE := report.txt
 
 vpath %.c ${SDDF} ${ECHO_SERVER}
 
-IMAGES := eth_driver.elf lwip.elf benchmark.elf idle.elf network_virt_rx.elf\
+IMAGES := eth_driver.elf echo.elf benchmark.elf idle.elf network_virt_rx.elf\
 	  network_virt_tx.elf copy.elf timer_driver.elf uart_driver.elf serial_virt_tx.elf
 
 CFLAGS := -mcpu=$(CPU) \
@@ -41,14 +41,13 @@ CFLAGS := -mcpu=$(CPU) \
 	  -I${ETHERNET_CONFIG_INCLUDE} \
 	  -I$(SERIAL_CONFIG_INCLUDE) \
 	  -I${SDDF}/$(LWIPDIR)/include \
-	  -I${SDDF}/$(LWIPDIR)/include/ipv4 \
 	  -MD \
 	  -MP
 
 LDFLAGS := -L$(BOARD_DIR)/lib -L${LIBC}
 LIBS := --start-group -lmicrokit -Tmicrokit.ld -lc libsddf_util_debug.a --end-group
 
-CHECK_FLAGS_BOARD_MD5:=.board_cflags-$(shell echo -- ${CFLAGS} ${BOARD} ${MICROKIT_CONFIG} | shasum | sed 's/ *-//')
+CHECK_FLAGS_BOARD_MD5 := .board_cflags-$(shell echo -- ${CFLAGS} ${BOARD} ${MICROKIT_CONFIG} | shasum | sed 's/ *-//')
 
 ${CHECK_FLAGS_BOARD_MD5}:
 	-rm -f .board_cflags-*
@@ -64,17 +63,16 @@ include ${SDDF}/${LWIPDIR}/Filelists.mk
 NETIFFILES:=$(LWIPDIR)/netif/ethernet.c
 
 # LWIPFILES: All the above.
-LWIPFILES=lwip.c $(COREFILES) $(CORE4FILES) $(NETIFFILES)
-LWIP_OBJS := $(LWIPFILES:.c=.o) lwip.o utilization_socket.o \
+LWIPFILES = echo.c $(COREFILES) $(CORE4FILES) $(NETIFFILES)
+LWIP_OBJS := $(LWIPFILES:.c=.o) echo.o utilization_socket.o \
 	     udp_echo_socket.o tcp_echo_socket.o
 
-OBJS := $(LWIP_OBJS)
-DEPS := $(filter %.d,$(OBJS:.o=.d))
+DEPS := $(filter %.d,$(LWIP_OBJS:.o=.d))
 
 all: loader.img
 
 ${LWIP_OBJS}: ${CHECK_FLAGS_BOARD_MD5}
-lwip.elf: $(LWIP_OBJS) libsddf_util.a
+echo.elf: $(LWIP_OBJS) libsddf_util.a lib_sddf_lwip.a
 	$(LD) $(LDFLAGS) $^ $(LIBS) -o $@
 
 LWIPDIRS := $(addprefix ${LWIPDIR}/, core/ipv4 netif api)
@@ -92,6 +90,9 @@ ${IMAGE_FILE} $(REPORT_FILE): $(IMAGES) $(SYSTEM_FILE)
 
 include ${SDDF}/util/util.mk
 include ${SDDF}/network/components/network_components.mk
+# Specify how many pbufs sDDF LWIP library requires for all clients
+MAX_NUM_BUFFS=512
+include ${SDDF}/network/lib_sddf_lwip/lib_sddf_lwip.mk
 include ${ETHERNET_DRIVER}/eth_driver.mk
 include ${BENCHMARK}/benchmark.mk
 include ${TIMER_DRIVER}/timer_driver.mk
diff --git a/examples/echo_server/lwip.c b/examples/echo_server/lwip.c
deleted file mode 100644
index 7f21022cd..000000000
--- a/examples/echo_server/lwip.c
+++ /dev/null
@@ -1,395 +0,0 @@
-/*
- * Copyright 2022, UNSW
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#include <stdbool.h>
-#include <stdint.h>
-#include <microkit.h>
-#include <sddf/util/util.h>
-#include <sddf/util/printf.h>
-#include <sddf/network/queue.h>
-#include <sddf/network/util.h>
-#include <sddf/serial/queue.h>
-#include <sddf/timer/client.h>
-#include <sddf/benchmark/sel4bench.h>
-#include <serial_config.h>
-#include <ethernet_config.h>
-#include <string.h>
-#include "lwip/init.h"
-#include "netif/etharp.h"
-#include "lwip/pbuf.h"
-#include "lwip/netif.h"
-#include "lwip/stats.h"
-#include "lwip/snmp.h"
-#include "lwip/sys.h"
-#include "lwip/timeouts.h"
-#include "lwip/dhcp.h"
-
-#include "echo.h"
-
-#define SERIAL_TX_CH 0
-#define TIMER  1
-#define RX_CH  2
-#define TX_CH  3
-
-char *serial_tx_data;
-serial_queue_t *serial_tx_queue;
-serial_queue_handle_t serial_tx_queue_handle;
-
-#define LWIP_TICK_MS 100
-#define NUM_PBUFFS NET_MAX_CLIENT_QUEUE_SIZE
-
-net_queue_t *rx_free;
-net_queue_t *rx_active;
-net_queue_t *tx_free;
-net_queue_t *tx_active;
-uintptr_t rx_buffer_data_region;
-uintptr_t tx_buffer_data_region;
-
-/* Booleans to indicate whether packets have been enqueued during notification handling */
-static bool notify_tx;
-static bool notify_rx;
-
-/* Wrapper over custom_pbuf structure to keep track of buffer offset */
-typedef struct pbuf_custom_offset {
-    struct pbuf_custom custom;
-    uint64_t offset;
-} pbuf_custom_offset_t;
-
-LWIP_MEMPOOL_DECLARE(
-    RX_POOL,
-    NUM_PBUFFS * 2,
-    sizeof(struct pbuf_custom_offset),
-    "Zero-copy RX pool"
-);
-
-typedef struct state {
-    struct netif netif;
-    uint8_t mac[ETH_HWADDR_LEN];
-    net_queue_handle_t rx_queue;
-    net_queue_handle_t tx_queue;
-    struct pbuf *head;
-    struct pbuf *tail;
-} state_t;
-
-state_t state;
-
-void set_timeout(void)
-{
-    sddf_timer_set_timeout(TIMER, LWIP_TICK_MS * NS_IN_MS);
-}
-
-uint32_t sys_now(void)
-{
-    return sddf_timer_time_now(TIMER) / NS_IN_MS;
-}
-
-/**
- * Free a pbuf. This also returns the underlying buffer to the receive free ring.
- *
- * @param p pbuf to free.
- */
-static void interface_free_buffer(struct pbuf *p)
-{
-    SYS_ARCH_DECL_PROTECT(old_level);
-    pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *)p;
-    SYS_ARCH_PROTECT(old_level);
-    net_buff_desc_t buffer = {custom_pbuf_offset->offset, 0};
-    int err = net_enqueue_free(&(state.rx_queue), buffer);
-    assert(!err);
-    notify_rx = true;
-    LWIP_MEMPOOL_FREE(RX_POOL, custom_pbuf_offset);
-    SYS_ARCH_UNPROTECT(old_level);
-}
-
-/**
- * Create a pbuf structure to pass to the network interface.
- *
- * @param state client state data.
- * @param buffer shared buffer containing the data.
- * @param length length of data.
- *
- * @return the newly created pbuf. Can be cast to pbuf_custom.
- */
-static struct pbuf *create_interface_buffer(uint64_t offset, size_t length)
-{
-    pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *) LWIP_MEMPOOL_ALLOC(RX_POOL);
-    custom_pbuf_offset->offset = offset;
-    custom_pbuf_offset->custom.custom_free_function = interface_free_buffer;
-
-    return pbuf_alloced_custom(
-               PBUF_RAW,
-               length,
-               PBUF_REF,
-               &custom_pbuf_offset->custom,
-               (void *)(offset + rx_buffer_data_region),
-               NET_BUFFER_SIZE
-           );
-}
-
-/**
- * Stores a pbuf to be transmitted upon available transmit buffers.
- *
- * @param p pbuf to be stored.
- */
-void enqueue_pbufs(struct pbuf *p)
-{
-    /* Indicate to the multiplexer that we require transmit free buffers */
-    net_request_signal_free(&state.tx_queue);
-
-    if (state.head == NULL) {
-        state.head = p;
-    } else {
-        state.tail->next_chain = p;
-    }
-    state.tail = p;
-
-    /* Increment refernce count to ensure this pbuf is not freed by lwip */
-    pbuf_ref(p);
-}
-
-/**
- * Insert pbuf into transmit active queue. If no free buffers available or transmit active queue is full,
- * stores pbuf to be sent upon buffers becoming available.
- * */
-static err_t lwip_eth_send(struct netif *netif, struct pbuf *p)
-{
-    if (p->tot_len > NET_BUFFER_SIZE) {
-        sddf_dprintf("LWIP|ERROR: attempted to send a packet of size  %u > BUFFER SIZE  %u\n", p->tot_len, NET_BUFFER_SIZE);
-        return ERR_MEM;
-    }
-
-    if (net_queue_empty_free(&state.tx_queue)) {
-        enqueue_pbufs(p);
-        return ERR_OK;
-    }
-
-    net_buff_desc_t buffer;
-    int err = net_dequeue_free(&state.tx_queue, &buffer);
-    assert(!err);
-
-    uintptr_t frame = buffer.io_or_offset + tx_buffer_data_region;
-    uint16_t copied = 0;
-    for (struct pbuf *curr = p; curr != NULL; curr = curr->next) {
-        memcpy((void *)(frame + copied), curr->payload, curr->len);
-        copied += curr->len;
-    }
-
-    buffer.len = copied;
-    err = net_enqueue_active(&state.tx_queue, buffer);
-    assert(!err);
-
-    notify_tx = true;
-
-    return ERR_OK;
-}
-
-void transmit(void)
-{
-    bool reprocess = true;
-    while (reprocess) {
-        while (state.head != NULL && !net_queue_empty_free(&state.tx_queue)) {
-            err_t err = lwip_eth_send(&state.netif, state.head);
-            if (err == ERR_MEM) {
-                sddf_dprintf("LWIP|ERROR: attempted to send a packet of size  %u > BUFFER SIZE  %u\n", state.head->tot_len,
-                             NET_BUFFER_SIZE);
-            } else if (err != ERR_OK) {
-                sddf_dprintf("LWIP|ERROR: unkown error when trying to send pbuf  %p\n", state.head);
-            }
-
-            struct pbuf *temp = state.head;
-            state.head = temp->next_chain;
-            if (state.head == NULL) {
-                state.tail = NULL;
-            }
-            pbuf_free(temp);
-        }
-
-        /* Only request a signal if no more pbufs enqueud to send */
-        if (state.head == NULL || !net_queue_empty_free(&state.tx_queue)) {
-            net_cancel_signal_free(&state.tx_queue);
-        } else {
-            net_request_signal_free(&state.tx_queue);
-        }
-        reprocess = false;
-
-        if (state.head != NULL && !net_queue_empty_free(&state.tx_queue)) {
-            net_cancel_signal_free(&state.tx_queue);
-            reprocess = true;
-        }
-    }
-}
-
-void receive(void)
-{
-    bool reprocess = true;
-    while (reprocess) {
-        while (!net_queue_empty_active(&state.rx_queue)) {
-            net_buff_desc_t buffer;
-            int err = net_dequeue_active(&state.rx_queue, &buffer);
-            assert(!err);
-
-            struct pbuf *p = create_interface_buffer(buffer.io_or_offset, buffer.len);
-            assert(p != NULL);
-            if (state.netif.input(p, &state.netif) != ERR_OK) {
-                sddf_dprintf("LWIP|ERROR: unkown error inputting pbuf into network stack\n");
-                pbuf_free(p);
-            }
-        }
-
-        net_request_signal_active(&state.rx_queue);
-        reprocess = false;
-
-        if (!net_queue_empty_active(&state.rx_queue)) {
-            net_cancel_signal_active(&state.rx_queue);
-            reprocess = true;
-        }
-    }
-}
-
-/**
- * Initialise the network interface data structure.
- *
- * @param netif network interface data structuer.
- */
-static err_t ethernet_init(struct netif *netif)
-{
-    if (netif->state == NULL) {
-        return ERR_ARG;
-    }
-    state_t *data = netif->state;
-
-    netif->hwaddr[0] = data->mac[0];
-    netif->hwaddr[1] = data->mac[1];
-    netif->hwaddr[2] = data->mac[2];
-    netif->hwaddr[3] = data->mac[3];
-    netif->hwaddr[4] = data->mac[4];
-    netif->hwaddr[5] = data->mac[5];
-    netif->mtu = ETHER_MTU;
-    netif->hwaddr_len = ETHARP_HWADDR_LEN;
-    netif->output = etharp_output;
-    netif->linkoutput = lwip_eth_send;
-    NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED);
-    netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP | NETIF_FLAG_IGMP;
-    return ERR_OK;
-}
-
-/* Callback function that prints DHCP supplied IP address. */
-static void netif_status_callback(struct netif *netif)
-{
-    if (dhcp_supplied_address(netif)) {
-        sddf_printf("LWIP|NOTICE: DHCP request for %s returned IP address: %s\n", microkit_name,
-                    ip4addr_ntoa(netif_ip4_addr(netif)));
-    }
-}
-
-void init(void)
-{
-    serial_cli_queue_init_sys(microkit_name, NULL, NULL, NULL, &serial_tx_queue_handle, serial_tx_queue, serial_tx_data);
-    serial_putchar_init(SERIAL_TX_CH, &serial_tx_queue_handle);
-
-    size_t rx_size, tx_size;
-    net_cli_queue_size(microkit_name, &rx_size, &tx_size);
-    net_queue_init(&state.rx_queue, rx_free, rx_active, rx_size);
-    net_queue_init(&state.tx_queue, tx_free, tx_active, tx_size);
-    net_buffers_init(&state.tx_queue, 0);
-
-    lwip_init();
-    set_timeout();
-
-    LWIP_MEMPOOL_INIT(RX_POOL);
-
-    uint64_t mac_addr = net_cli_mac_addr(microkit_name);
-    net_set_mac_addr(state.mac, mac_addr);
-
-    /* Set dummy IP configuration values to get lwIP bootstrapped  */
-    struct ip4_addr netmask, ipaddr, gw, multicast;
-    ipaddr_aton("0.0.0.0", &gw);
-    ipaddr_aton("0.0.0.0", &ipaddr);
-    ipaddr_aton("0.0.0.0", &multicast);
-    ipaddr_aton("255.255.255.0", &netmask);
-
-    state.netif.name[0] = 'e';
-    state.netif.name[1] = '0';
-
-    if (!netif_add(&(state.netif), &ipaddr, &netmask, &gw, (void *)&state,
-                   ethernet_init, ethernet_input)) {
-        sddf_dprintf("LWIP|ERROR: Netif add returned NULL\n");
-    }
-
-    netif_set_default(&(state.netif));
-    netif_set_status_callback(&(state.netif), netif_status_callback);
-    netif_set_up(&(state.netif));
-
-    if (dhcp_start(&(state.netif))) {
-        sddf_dprintf("LWIP|ERROR: failed to start DHCP negotiation\n");
-    }
-
-    setup_udp_socket();
-    setup_utilization_socket();
-    setup_tcp_socket();
-
-    if (notify_rx && net_require_signal_free(&state.rx_queue)) {
-        net_cancel_signal_free(&state.rx_queue);
-        notify_rx = false;
-        if (!microkit_have_signal) {
-            microkit_deferred_notify(RX_CH);
-        } else if (microkit_signal_cap != BASE_OUTPUT_NOTIFICATION_CAP + RX_CH) {
-            microkit_notify(RX_CH);
-        }
-    }
-
-    if (notify_tx && net_require_signal_active(&state.tx_queue)) {
-        net_cancel_signal_active(&state.tx_queue);
-        notify_tx = false;
-        if (!microkit_have_signal) {
-            microkit_deferred_notify(TX_CH);
-        } else if (microkit_signal_cap != BASE_OUTPUT_NOTIFICATION_CAP + TX_CH) {
-            microkit_notify(TX_CH);
-        }
-    }
-}
-
-void notified(microkit_channel ch)
-{
-    switch (ch) {
-    case RX_CH:
-        receive();
-        break;
-    case TIMER:
-        sys_check_timeouts();
-        set_timeout();
-        break;
-    case TX_CH:
-        transmit();
-        receive();
-        break;
-    case SERIAL_TX_CH:
-        // Nothing to do
-        break;
-    default:
-        sddf_dprintf("LWIP|LOG: received notification on unexpected channel: %u\n", ch);
-        break;
-    }
-
-    if (notify_rx && net_require_signal_free(&state.rx_queue)) {
-        net_cancel_signal_free(&state.rx_queue);
-        notify_rx = false;
-        if (!microkit_have_signal) {
-            microkit_deferred_notify(RX_CH);
-        } else if (microkit_signal_cap != BASE_OUTPUT_NOTIFICATION_CAP + RX_CH) {
-            microkit_notify(RX_CH);
-        }
-    }
-
-    if (notify_tx && net_require_signal_active(&state.tx_queue)) {
-        net_cancel_signal_active(&state.tx_queue);
-        notify_tx = false;
-        if (!microkit_have_signal) {
-            microkit_deferred_notify(TX_CH);
-        } else if (microkit_signal_cap != BASE_OUTPUT_NOTIFICATION_CAP + TX_CH) {
-            microkit_notify(TX_CH);
-        }
-    }
-}

From dc8b994c15c30b9f2c817878e658a8fa50ab3f36 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Fri, 6 Sep 2024 15:43:21 +1000
Subject: [PATCH 04/18] Add absolute path to lib_sddf_lwip dir

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 network/lib_sddf_lwip/lib_sddf_lwip.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.mk b/network/lib_sddf_lwip/lib_sddf_lwip.mk
index 7f80c39bc..c0158ae75 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.mk
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.mk
@@ -10,7 +10,7 @@ endif
 
 CFLAGS += -DMAX_NUM_BUFFS=$(MAX_NUM_BUFFS)
 
-LIB_SDDF_LWIP_DIR := network/lib_sddf_lwip
+LIB_SDDF_LWIP_DIR := ${SDDF}/network/lib_sddf_lwip
 LIB_SDDF_LWIP_FILES := $(addprefix ${LIB_SDDF_LWIP_DIR}/, lib_sddf_lwip.c)
 LIB_SDDF_LWIP_OBJS := $(LIB_SDDF_LWIP_FILES:.c=.o)
 

From c08780084fe5c40017bb493d15b2d24e57ed4ed0 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Fri, 6 Sep 2024 17:15:14 +1000
Subject: [PATCH 05/18] Update description for lib sddf lwip notify function

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 include/sddf/network/lib_sddf_lwip.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/sddf/network/lib_sddf_lwip.h b/include/sddf/network/lib_sddf_lwip.h
index ac8c668a0..494437213 100644
--- a/include/sddf/network/lib_sddf_lwip.h
+++ b/include/sddf/network/lib_sddf_lwip.h
@@ -9,8 +9,7 @@
 #include <sddf/network/queue.h>
 #include "lwip/pbuf.h"
 
-#define LINK_SPEED 1000000000 // Gigabit
-#define ETHER_MTU 1500
+
 
 /* Definitions for sDDF error constants. */
 typedef enum {
@@ -71,8 +70,8 @@ void sddf_lwip_process_rx(void);
 
 /**
  * Handles the sending of notifications to the network RX and TX virtualisers.
- * Must be invoked at the end of each event handling loop to ensure outgoing
- * buffers are processed by the virtualisers.
+ * Must be invoked at the end of each event handling loop and initialisation
+ * to ensure outgoing buffers are processed by the virtualisers.
  */
 void sddf_lwip_maybe_notify(void);
 

From df3847091a7f6b2e7cbd5f47d200f8c429bb0213 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Fri, 6 Sep 2024 17:20:49 +1000
Subject: [PATCH 06/18] Add prefixes to lib sddf constants

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 include/sddf/network/lib_sddf_lwip.h  | 4 ++++
 network/lib_sddf_lwip/lib_sddf_lwip.c | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/sddf/network/lib_sddf_lwip.h b/include/sddf/network/lib_sddf_lwip.h
index 494437213..4c92583a4 100644
--- a/include/sddf/network/lib_sddf_lwip.h
+++ b/include/sddf/network/lib_sddf_lwip.h
@@ -9,7 +9,11 @@
 #include <sddf/network/queue.h>
 #include "lwip/pbuf.h"
 
+/* Default gigabit link speed. */
+#define SDDF_LWIP_LINK_SPEED 1000000000
 
+/* Default ethernet MTU. */
+#define SDDF_LWIP_ETHER_MTU 1500
 
 /* Definitions for sDDF error constants. */
 typedef enum {
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index 94ff95542..2d3571578 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -271,11 +271,11 @@ static err_t ethernet_init(struct netif *netif) {
     }
     
     net_set_mac_addr(netif->hwaddr, lwip_state.mac);
-    netif->mtu = ETHER_MTU;
+    netif->mtu = SDDF_LWIP_ETHER_MTU;
     netif->hwaddr_len = ETHARP_HWADDR_LEN;
     netif->output = etharp_output;
     netif->linkoutput = lwip_eth_send;
-    NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED);
+    NETIF_INIT_SNMP(netif, snmp_ifType_ethernet_csmacd, SDDF_LWIP_LINK_SPEED);
     netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP | NETIF_FLAG_IGMP;
 
     return ERR_OK;

From 69a27d75b0015c26273fbc24d714201eb787bfcb Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Fri, 6 Sep 2024 17:30:44 +1000
Subject: [PATCH 07/18] Add prefix to NUM_BUFFS constant for lib sddf lwip

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.mk           | 2 +-
 network/lib_sddf_lwip/lib_sddf_lwip.c  | 2 +-
 network/lib_sddf_lwip/lib_sddf_lwip.mk | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/examples/echo_server/echo.mk b/examples/echo_server/echo.mk
index 0434cf57a..c32d41ce2 100644
--- a/examples/echo_server/echo.mk
+++ b/examples/echo_server/echo.mk
@@ -91,7 +91,7 @@ ${IMAGE_FILE} $(REPORT_FILE): $(IMAGES) $(SYSTEM_FILE)
 include ${SDDF}/util/util.mk
 include ${SDDF}/network/components/network_components.mk
 # Specify how many pbufs sDDF LWIP library requires for all clients
-MAX_NUM_BUFFS=512
+SDDF_LWIP_NUM_BUFFS=512
 include ${SDDF}/network/lib_sddf_lwip/lib_sddf_lwip.mk
 include ${ETHERNET_DRIVER}/eth_driver.mk
 include ${BENCHMARK}/benchmark.mk
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index 2d3571578..8e5858103 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -66,7 +66,7 @@ typedef struct pbuf_custom_offset {
 
 LWIP_MEMPOOL_DECLARE(
     RX_POOL,
-    MAX_NUM_BUFFS * 2,
+    SDDF_LWIP_NUM_BUFFS * 2,
     sizeof(struct pbuf_custom_offset),
     "Zero-copy RX pool"
 );
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.mk b/network/lib_sddf_lwip/lib_sddf_lwip.mk
index c0158ae75..4ce8d3908 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.mk
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.mk
@@ -4,11 +4,11 @@
 # SPDX-License-Identifier: BSD-2-Clause
 #
 
-ifeq ($(strip $(MAX_NUM_BUFFS)),)
+ifeq ($(strip $(SDDF_LWIP_NUM_BUFFS)),)
 $(error MAX_NUM_BUFFS must be specified)
 endif
 
-CFLAGS += -DMAX_NUM_BUFFS=$(MAX_NUM_BUFFS)
+CFLAGS += -DSDDF_LWIP_NUM_BUFFS=$(SDDF_LWIP_NUM_BUFFS)
 
 LIB_SDDF_LWIP_DIR := ${SDDF}/network/lib_sddf_lwip
 LIB_SDDF_LWIP_FILES := $(addprefix ${LIB_SDDF_LWIP_DIR}/, lib_sddf_lwip.c)

From d122ece74d48434b503aff9e0b8ca1dbdf3221db Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Fri, 6 Sep 2024 18:56:58 +1000
Subject: [PATCH 08/18] Fix style

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.c           |  8 ++-
 include/sddf/network/lib_sddf_lwip.h  |  4 +-
 network/lib_sddf_lwip/lib_sddf_lwip.c | 88 ++++++++++++++++-----------
 3 files changed, 58 insertions(+), 42 deletions(-)

diff --git a/examples/echo_server/echo.c b/examples/echo_server/echo.c
index f53d3d265..81706d831 100644
--- a/examples/echo_server/echo.c
+++ b/examples/echo_server/echo.c
@@ -46,17 +46,19 @@ struct pbuf *tail;
 /**
  * Netif status callback function that output's client's Microkit name and
  * obtained IP address.
- * 
+ *
  * @param ip_addr ip address of the client.
  */
-void netif_status_callback(char *ip_addr) {
+void netif_status_callback(char *ip_addr)
+{
     sddf_printf("DHCP request finished, IP address for netif %s is: %s\n", microkit_name, ip_addr);
 }
 
 /**
  * Sets a timeout for the next lwip tick.
  */
-void set_timeout(void) {
+void set_timeout(void)
+{
     sddf_timer_set_timeout(TIMER, LWIP_TICK_MS * NS_IN_MS);
 }
 
diff --git a/include/sddf/network/lib_sddf_lwip.h b/include/sddf/network/lib_sddf_lwip.h
index 4c92583a4..1f389d20c 100644
--- a/include/sddf/network/lib_sddf_lwip.h
+++ b/include/sddf/network/lib_sddf_lwip.h
@@ -47,7 +47,7 @@ typedef void (*sddf_lwip_netif_status_callback_fn)(char *ip_addr);
  */
 typedef net_sddf_err_t (*sddf_lwip_handle_empty_tx_free_fn)(struct pbuf *p);
 
-/** 
+/**
  * Checks LWIP system timeouts. Should be invoked after every LWIP tick.
  */
 void sddf_lwip_process_timeout(void);
@@ -65,7 +65,7 @@ void sddf_lwip_process_timeout(void);
  */
 net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p);
 
-/** 
+/**
  * Handles the passing of incoming packets in sDDF buffers to LWIP. Must be
  * called to process the sDDF RX queue each time a notification is received
  * from the network virtualiser.
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index 8e5858103..135abfb92 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -76,23 +76,24 @@ sddf_state_t sddf_state;
 
 /**
  * Helper function to convert sddf errors to lwip errors.
- * 
+ *
  * @param sddf_err sddf error.
  *
- * @return Equivalent lwip error. 
+ * @return Equivalent lwip error.
  */
-static err_t sddf_err_to_lwip_err(net_sddf_err_t sddf_err) {
+static err_t sddf_err_to_lwip_err(net_sddf_err_t sddf_err)
+{
     switch (sddf_err) {
-        case SDDF_ERR_OK:
-            return ERR_OK;
-        case SDDF_ERR_PBUF:
-            return ERR_BUF;
-        case SDDF_ERR_NO_BUF:
-            return ERR_MEM;
-        case SDDF_ERR_ENQUEUED:
-            return ERR_OK;
-        case SDDF_ERR_UNHANDLED:
-            return ERR_MEM;
+    case SDDF_ERR_OK:
+        return ERR_OK;
+    case SDDF_ERR_PBUF:
+        return ERR_BUF;
+    case SDDF_ERR_NO_BUF:
+        return ERR_MEM;
+    case SDDF_ERR_ENQUEUED:
+        return ERR_OK;
+    case SDDF_ERR_UNHANDLED:
+        return ERR_MEM;
     }
     return ERR_ARG;
 }
@@ -100,38 +101,42 @@ static err_t sddf_err_to_lwip_err(net_sddf_err_t sddf_err) {
 /**
  * Default netif status callback function. Prints client MAC address and
  * obtained ip address.
- * 
- * @param ip_addr Obtained ip address as a string. 
+ *
+ * @param ip_addr Obtained ip address as a string.
  */
-static void netif_status_callback_default(char *ip_addr) {
+static void netif_status_callback_default(char *ip_addr)
+{
     uint8_t *mac = lwip_state.netif.hwaddr;
     lwip_state.err_output("LWIP|NOTICE: DHCP request for mac "
-                       "%02lx:%02lx:%02lx:%02lx:%02lx:%02lx "
-                       "returned ip address: %s\n", mac[0],
-                       mac[1], mac[2], mac[3], mac[4], mac[5],
-                       ip_addr);
+                          "%02lx:%02lx:%02lx:%02lx:%02lx:%02lx "
+                          "returned ip address: %s\n", mac[0],
+                          mac[1], mac[2], mac[3], mac[4], mac[5],
+                          ip_addr);
 }
 
 /**
  * Default handling function to be called during transmission if tx free
  * queue is empty.
- * 
+ *
  * @param p pbuf that could not be sent due to queue being empty.
  *
  * @return Simply returns the sddf error indicating nothing was done.
  */
-static net_sddf_err_t handle_empty_tx_free_default(struct pbuf *p) {
+static net_sddf_err_t handle_empty_tx_free_default(struct pbuf *p)
+{
     return SDDF_ERR_UNHANDLED;
 }
 
 /**
  * Returns current time from the timer.
  */
-uint32_t sys_now(void) {
+uint32_t sys_now(void)
+{
     return sddf_timer_time_now(sddf_state.timer_ch) / NS_IN_MS;
 }
 
-void sddf_lwip_process_timeout() {
+void sddf_lwip_process_timeout()
+{
     sys_check_timeouts();
 }
 
@@ -140,7 +145,8 @@ void sddf_lwip_process_timeout() {
  *
  * @param p pbuf to free.
  */
-static void interface_free_buffer(struct pbuf *p) {
+static void interface_free_buffer(struct pbuf *p)
+{
     SYS_ARCH_DECL_PROTECT(old_level);
     pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *)p;
     SYS_ARCH_PROTECT(old_level);
@@ -160,7 +166,8 @@ static void interface_free_buffer(struct pbuf *p) {
  *
  * @return the newly created pbuf. Can be cast to pbuf_custom.
  */
-static struct pbuf *create_interface_buffer(uint64_t offset, size_t length) {
+static struct pbuf *create_interface_buffer(uint64_t offset, size_t length)
+{
     pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *) LWIP_MEMPOOL_ALLOC(RX_POOL);
     custom_pbuf_offset->offset = offset;
     custom_pbuf_offset->custom.custom_free_function = interface_free_buffer;
@@ -186,7 +193,8 @@ static struct pbuf *create_interface_buffer(uint64_t offset, size_t length) {
  * sddf buffers available, handle_empty_tx_free will be called with the pbuf,
  * and the equivalent lwip error will be returned.
  */
-static err_t lwip_eth_send(struct netif *netif, struct pbuf *p) {
+static err_t lwip_eth_send(struct netif *netif, struct pbuf *p)
+{
     if (p->tot_len > NET_BUFFER_SIZE) {
         lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
                               p->tot_len, NET_BUFFER_SIZE);
@@ -217,7 +225,8 @@ static err_t lwip_eth_send(struct netif *netif, struct pbuf *p) {
     return ERR_OK;
 }
 
-net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p) {
+net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p)
+{
     if (p->tot_len > NET_BUFFER_SIZE) {
         lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
                               p->tot_len, NET_BUFFER_SIZE);
@@ -234,7 +243,8 @@ net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p) {
     return SDDF_ERR_OK;
 }
 
-void sddf_lwip_process_rx(void) {
+void sddf_lwip_process_rx(void)
+{
     bool reprocess = true;
     while (reprocess) {
         while (!net_queue_empty_active(&sddf_state.rx_queue)) {
@@ -265,11 +275,12 @@ void sddf_lwip_process_rx(void) {
  *
  * @param netif network interface data structure.
  */
-static err_t ethernet_init(struct netif *netif) {
+static err_t ethernet_init(struct netif *netif)
+{
     if (netif->state == NULL) {
         return ERR_ARG;
     }
-    
+
     net_set_mac_addr(netif->hwaddr, lwip_state.mac);
     netif->mtu = SDDF_LWIP_ETHER_MTU;
     netif->hwaddr_len = ETHARP_HWADDR_LEN;
@@ -288,7 +299,8 @@ static err_t ethernet_init(struct netif *netif) {
  *
  * @param netif network interface data structure.
  */
-static void netif_status_callback(struct netif *netif) {
+static void netif_status_callback(struct netif *netif)
+{
     if (dhcp_supplied_address(netif)) {
         char ip4_str[IP4ADDR_STRLEN_MAX];
         lwip_state.netif_callback(ip4addr_ntoa_r(netif_ip4_addr(netif), ip4_str, IP4ADDR_STRLEN_MAX));
@@ -302,7 +314,8 @@ void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
                     microkit_channel timer_ch,
                     uint64_t mac, sddf_lwip_err_output_fn err_output,
                     sddf_lwip_netif_status_callback_fn netif_callback,
-                    sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free) {
+                    sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free)
+{
     /* Initialise sddf state */
     sddf_state.rx_queue = rx_queue;
     sddf_state.tx_queue = tx_queue;
@@ -314,9 +327,9 @@ void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
 
     /* Initialise lwip state */
     lwip_state.mac = mac;
-    lwip_state.err_output = (err_output == NULL)? sddf_printf_: err_output;
-    lwip_state.netif_callback = (netif_callback == NULL)? netif_status_callback_default: netif_callback;
-    lwip_state.handle_empty_tx_free = (handle_empty_tx_free == NULL)? handle_empty_tx_free_default: handle_empty_tx_free;
+    lwip_state.err_output = (err_output == NULL) ? sddf_printf_ : err_output;
+    lwip_state.netif_callback = (netif_callback == NULL) ? netif_status_callback_default : netif_callback;
+    lwip_state.handle_empty_tx_free = (handle_empty_tx_free == NULL) ? handle_empty_tx_free_default : handle_empty_tx_free;
 
     lwip_init();
 
@@ -346,7 +359,8 @@ void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
     }
 }
 
-void sddf_lwip_maybe_notify() {
+void sddf_lwip_maybe_notify()
+{
     if (sddf_state.notify_rx && net_require_signal_free(&sddf_state.rx_queue)) {
         net_cancel_signal_free(&sddf_state.rx_queue);
         sddf_state.notify_rx = false;

From 917941c6f9c4110e4819b08f35c844ba18e57e1f Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Mon, 9 Sep 2024 16:40:37 +1000
Subject: [PATCH 09/18] Rename LWIP_OBJS to ECHO_OBJS

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.mk | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/examples/echo_server/echo.mk b/examples/echo_server/echo.mk
index c32d41ce2..3a613f85d 100644
--- a/examples/echo_server/echo.mk
+++ b/examples/echo_server/echo.mk
@@ -63,20 +63,20 @@ include ${SDDF}/${LWIPDIR}/Filelists.mk
 NETIFFILES:=$(LWIPDIR)/netif/ethernet.c
 
 # LWIPFILES: All the above.
-LWIPFILES = echo.c $(COREFILES) $(CORE4FILES) $(NETIFFILES)
-LWIP_OBJS := $(LWIPFILES:.c=.o) echo.o utilization_socket.o \
+LWIPFILES := $(COREFILES) $(CORE4FILES) $(NETIFFILES)
+ECHO_OBJS := $(LWIPFILES:.c=.o) echo.o utilization_socket.o \
 	     udp_echo_socket.o tcp_echo_socket.o
 
-DEPS := $(filter %.d,$(LWIP_OBJS:.o=.d))
+DEPS := $(filter %.d,$(ECHO_OBJS:.o=.d))
 
 all: loader.img
 
-${LWIP_OBJS}: ${CHECK_FLAGS_BOARD_MD5}
-echo.elf: $(LWIP_OBJS) libsddf_util.a lib_sddf_lwip.a
+${ECHO_OBJS}: ${CHECK_FLAGS_BOARD_MD5}
+echo.elf: $(ECHO_OBJS) lib_sddf_lwip.a libsddf_util.a
 	$(LD) $(LDFLAGS) $^ $(LIBS) -o $@
 
 LWIPDIRS := $(addprefix ${LWIPDIR}/, core/ipv4 netif api)
-${LWIP_OBJS}: |${BUILD_DIR}/${LWIPDIRS}
+${ECHO_OBJS}: |${BUILD_DIR}/${LWIPDIRS}
 ${BUILD_DIR}/${LWIPDIRS}:
 	mkdir -p $@
 

From 73f6f7c97b1886b0d77c7e3191c3ceca0c0a1387 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Mon, 9 Sep 2024 16:43:18 +1000
Subject: [PATCH 10/18] Remove unnecessary filter

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/echo_server/echo.mk b/examples/echo_server/echo.mk
index 3a613f85d..fe90d625f 100644
--- a/examples/echo_server/echo.mk
+++ b/examples/echo_server/echo.mk
@@ -67,7 +67,7 @@ LWIPFILES := $(COREFILES) $(CORE4FILES) $(NETIFFILES)
 ECHO_OBJS := $(LWIPFILES:.c=.o) echo.o utilization_socket.o \
 	     udp_echo_socket.o tcp_echo_socket.o
 
-DEPS := $(filter %.d,$(ECHO_OBJS:.o=.d))
+DEPS := $(ECHO_OBJS:.o=.d)
 
 all: loader.img
 

From 49e62e4a8578d0adad5ac39685e71200cb528314 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Mon, 9 Sep 2024 17:44:14 +1000
Subject: [PATCH 11/18] Only use SDDF_LWIP_NUM_BUFFS for building lib sddf lwip

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 network/lib_sddf_lwip/lib_sddf_lwip.mk | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.mk b/network/lib_sddf_lwip/lib_sddf_lwip.mk
index 4ce8d3908..8f71c02f8 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.mk
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.mk
@@ -8,12 +8,12 @@ ifeq ($(strip $(SDDF_LWIP_NUM_BUFFS)),)
 $(error MAX_NUM_BUFFS must be specified)
 endif
 
-CFLAGS += -DSDDF_LWIP_NUM_BUFFS=$(SDDF_LWIP_NUM_BUFFS)
-
 LIB_SDDF_LWIP_DIR := ${SDDF}/network/lib_sddf_lwip
 LIB_SDDF_LWIP_FILES := $(addprefix ${LIB_SDDF_LWIP_DIR}/, lib_sddf_lwip.c)
 LIB_SDDF_LWIP_OBJS := $(LIB_SDDF_LWIP_FILES:.c=.o)
 
+${LIB_SDDF_LWIP_OBJS}: CFLAGS += -DSDDF_LWIP_NUM_BUFFS=$(SDDF_LWIP_NUM_BUFFS)
+
 ${LIB_SDDF_LWIP_OBJS}: | ${LIB_SDDF_LWIP_DIR} ${CHECK_FLAGS_BOARD_MD5}
 ${LIB_SDDF_LWIP_DIR}:
 	mkdir -p $@

From 4db3f63000d4fd2081ae73cb9709ce6bf424e417 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Mon, 9 Sep 2024 17:47:22 +1000
Subject: [PATCH 12/18] SDDF_LWIP_NUM_BUFS rename

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.mk           | 2 +-
 network/lib_sddf_lwip/lib_sddf_lwip.c  | 2 +-
 network/lib_sddf_lwip/lib_sddf_lwip.mk | 8 ++++----
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/examples/echo_server/echo.mk b/examples/echo_server/echo.mk
index fe90d625f..7240089b8 100644
--- a/examples/echo_server/echo.mk
+++ b/examples/echo_server/echo.mk
@@ -91,7 +91,7 @@ ${IMAGE_FILE} $(REPORT_FILE): $(IMAGES) $(SYSTEM_FILE)
 include ${SDDF}/util/util.mk
 include ${SDDF}/network/components/network_components.mk
 # Specify how many pbufs sDDF LWIP library requires for all clients
-SDDF_LWIP_NUM_BUFFS=512
+SDDF_LWIP_NUM_BUFS=512
 include ${SDDF}/network/lib_sddf_lwip/lib_sddf_lwip.mk
 include ${ETHERNET_DRIVER}/eth_driver.mk
 include ${BENCHMARK}/benchmark.mk
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index 135abfb92..b4fe83755 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -66,7 +66,7 @@ typedef struct pbuf_custom_offset {
 
 LWIP_MEMPOOL_DECLARE(
     RX_POOL,
-    SDDF_LWIP_NUM_BUFFS * 2,
+    SDDF_LWIP_NUM_BUFS * 2,
     sizeof(struct pbuf_custom_offset),
     "Zero-copy RX pool"
 );
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.mk b/network/lib_sddf_lwip/lib_sddf_lwip.mk
index 8f71c02f8..9c8966efd 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.mk
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.mk
@@ -4,17 +4,17 @@
 # SPDX-License-Identifier: BSD-2-Clause
 #
 
-ifeq ($(strip $(SDDF_LWIP_NUM_BUFFS)),)
-$(error MAX_NUM_BUFFS must be specified)
+ifeq ($(strip $(SDDF_LWIP_NUM_BUFS)),)
+$(error SDDF_LWIP_NUM_BUFS must be specified)
 endif
 
 LIB_SDDF_LWIP_DIR := ${SDDF}/network/lib_sddf_lwip
 LIB_SDDF_LWIP_FILES := $(addprefix ${LIB_SDDF_LWIP_DIR}/, lib_sddf_lwip.c)
 LIB_SDDF_LWIP_OBJS := $(LIB_SDDF_LWIP_FILES:.c=.o)
 
-${LIB_SDDF_LWIP_OBJS}: CFLAGS += -DSDDF_LWIP_NUM_BUFFS=$(SDDF_LWIP_NUM_BUFFS)
+${LIB_SDDF_LWIP_OBJS}: CFLAGS += -DSDDF_LWIP_NUM_BUFS=$(SDDF_LWIP_NUM_BUFS)
 
-${LIB_SDDF_LWIP_OBJS}: | ${LIB_SDDF_LWIP_DIR} ${CHECK_FLAGS_BOARD_MD5}
+${LIB_SDDF_LWIP_OBJS}: ${CHECK_FLAGS_BOARD_MD5} | ${LIB_SDDF_LWIP_DIR}
 ${LIB_SDDF_LWIP_DIR}:
 	mkdir -p $@
 

From 6e15f97a54645dbd47d90afc7791de0a1edc7d80 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Mon, 9 Sep 2024 17:51:29 +1000
Subject: [PATCH 13/18] Use makefile snippet location rather than hardcoded
 location

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 network/lib_sddf_lwip/lib_sddf_lwip.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.mk b/network/lib_sddf_lwip/lib_sddf_lwip.mk
index 9c8966efd..17506e141 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.mk
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.mk
@@ -8,7 +8,7 @@ ifeq ($(strip $(SDDF_LWIP_NUM_BUFS)),)
 $(error SDDF_LWIP_NUM_BUFS must be specified)
 endif
 
-LIB_SDDF_LWIP_DIR := ${SDDF}/network/lib_sddf_lwip
+LIB_SDDF_LWIP_DIR := $(dir $(lastword $(MAKEFILE_LIST)))
 LIB_SDDF_LWIP_FILES := $(addprefix ${LIB_SDDF_LWIP_DIR}/, lib_sddf_lwip.c)
 LIB_SDDF_LWIP_OBJS := $(LIB_SDDF_LWIP_FILES:.c=.o)
 

From fabf5c6ccf5e97bec40a2e4cf43aa37f19b1038b Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Mon, 9 Sep 2024 17:59:38 +1000
Subject: [PATCH 14/18] Add attribute to print function

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 include/sddf/network/lib_sddf_lwip.h  | 4 ++--
 network/lib_sddf_lwip/lib_sddf_lwip.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/sddf/network/lib_sddf_lwip.h b/include/sddf/network/lib_sddf_lwip.h
index 1f389d20c..79adb3e37 100644
--- a/include/sddf/network/lib_sddf_lwip.h
+++ b/include/sddf/network/lib_sddf_lwip.h
@@ -32,7 +32,7 @@ typedef enum {
 /**
  * Function type for output of sDDF LWIP errors.
  */
-typedef int (*sddf_lwip_err_output_fn)(const char *format, ...);
+typedef int (*sddf_lwip_err_output_fn)(const char *format, ...) __attribute__((format(__printf__, 1, 2)));
 
 /**
  * Function type for netif status callback. Invoked by LWIP upon
@@ -111,4 +111,4 @@ void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
                     microkit_channel timer_ch,
                     uint64_t mac, sddf_lwip_err_output_fn err_output,
                     sddf_lwip_netif_status_callback_fn netif_callback,
-                    sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free);
\ No newline at end of file
+                    sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free);
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index b4fe83755..234a66e44 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -108,7 +108,7 @@ static void netif_status_callback_default(char *ip_addr)
 {
     uint8_t *mac = lwip_state.netif.hwaddr;
     lwip_state.err_output("LWIP|NOTICE: DHCP request for mac "
-                          "%02lx:%02lx:%02lx:%02lx:%02lx:%02lx "
+                          "%02x:%02x:%02x:%02x:%02x:%02x "
                           "returned ip address: %s\n", mac[0],
                           mac[1], mac[2], mac[3], mac[4], mac[5],
                           ip_addr);

From d06e9677648e62ec8c8d8488ea3aef25dea47c92 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Thu, 19 Sep 2024 19:22:16 +1000
Subject: [PATCH 15/18] Update err prefix

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.c           |  6 +++---
 include/sddf/network/lib_sddf_lwip.h  | 14 +++++++-------
 network/lib_sddf_lwip/lib_sddf_lwip.c | 14 +++++++-------
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/examples/echo_server/echo.c b/examples/echo_server/echo.c
index 81706d831..49da1147e 100644
--- a/examples/echo_server/echo.c
+++ b/examples/echo_server/echo.c
@@ -82,7 +82,7 @@ net_sddf_err_t enqueue_pbufs(struct pbuf *p)
     /* Increment reference count to ensure this pbuf is not freed by lwip */
     pbuf_ref(p);
 
-    return SDDF_ERR_OK;
+    return SDDF_LWIP_ERR_OK;
 }
 
 void transmit(void)
@@ -91,10 +91,10 @@ void transmit(void)
     while (reprocess) {
         while (head != NULL && !net_queue_empty_free(&net_tx_handle)) {
             net_sddf_err_t err = sddf_lwip_transmit_pbuf(head);
-            if (err == SDDF_ERR_PBUF) {
+            if (err == SDDF_LWIP_ERR_PBUF) {
                 sddf_dprintf("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
                              head->tot_len, NET_BUFFER_SIZE);
-            } else if (err != SDDF_ERR_OK) {
+            } else if (err != SDDF_LWIP_ERR_OK) {
                 sddf_dprintf("LWIP|ERROR: unkown error when trying to send pbuf %p\n", head);
             }
 
diff --git a/include/sddf/network/lib_sddf_lwip.h b/include/sddf/network/lib_sddf_lwip.h
index 79adb3e37..5b8dfea95 100644
--- a/include/sddf/network/lib_sddf_lwip.h
+++ b/include/sddf/network/lib_sddf_lwip.h
@@ -18,15 +18,15 @@
 /* Definitions for sDDF error constants. */
 typedef enum {
     /* No error, everything OK. */
-    SDDF_ERR_OK = 0,
+    SDDF_LWIP_ERR_OK = 0,
     /* Pbuf too large for sDDF buffer. */
-    SDDF_ERR_PBUF = -1,
+    SDDF_LWIP_ERR_PBUF = -1,
     /* No buffers available. */
-    SDDF_ERR_NO_BUF = -2,
+    SDDF_LWIP_ERR_NO_BUF = -2,
     /* Pbuf successfully enqueued to be sent later. */
-    SDDF_ERR_ENQUEUED    = -3,
+    SDDF_LWIP_ERR_ENQUEUED    = -3,
     /* Could not resolve error. */
-    SDDF_ERR_UNHANDLED    = -4
+    SDDF_LWIP_ERR_UNHANDLED    = -4
 } net_sddf_err_t;
 
 /**
@@ -57,8 +57,8 @@ void sddf_lwip_process_timeout(void);
  *
  * @param p pbuf to be transmitted.
  *
- * @return If the pbuf is sent successfully, SDDF_ERR_OK is returned and the
- * pbuf can safely be freed. If the pbuf is too large, SDDF_ERR_PBUF is
+ * @return If the pbuf is sent successfully, SDDF_LWIP_ERR_OK is returned and the
+ * pbuf can safely be freed. If the pbuf is too large, SDDF_LWIP_ERR_PBUF is
  * returned. If there are no free sDDF buffers available,
  * handle_empty_tx_free will be called with the pbuf, and the return value
  * will be returned.
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index 234a66e44..f56304301 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -84,15 +84,15 @@ sddf_state_t sddf_state;
 static err_t sddf_err_to_lwip_err(net_sddf_err_t sddf_err)
 {
     switch (sddf_err) {
-    case SDDF_ERR_OK:
+    case SDDF_LWIP_ERR_OK:
         return ERR_OK;
-    case SDDF_ERR_PBUF:
+    case SDDF_LWIP_ERR_PBUF:
         return ERR_BUF;
     case SDDF_ERR_NO_BUF:
         return ERR_MEM;
-    case SDDF_ERR_ENQUEUED:
+    case SDDF_LWIP_ERR_ENQUEUED:
         return ERR_OK;
-    case SDDF_ERR_UNHANDLED:
+    case SDDF_LWIP_ERR_UNHANDLED:
         return ERR_MEM;
     }
     return ERR_ARG;
@@ -124,7 +124,7 @@ static void netif_status_callback_default(char *ip_addr)
  */
 static net_sddf_err_t handle_empty_tx_free_default(struct pbuf *p)
 {
-    return SDDF_ERR_UNHANDLED;
+    return SDDF_LWIP_ERR_UNHANDLED;
 }
 
 /**
@@ -230,7 +230,7 @@ net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p)
     if (p->tot_len > NET_BUFFER_SIZE) {
         lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
                               p->tot_len, NET_BUFFER_SIZE);
-        return SDDF_ERR_PBUF;
+        return SDDF_LWIP_ERR_PBUF;
     }
 
     if (net_queue_empty_free(&sddf_state.tx_queue)) {
@@ -240,7 +240,7 @@ net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p)
     err_t err = lwip_eth_send(&lwip_state.netif, p);
     assert(!err);
 
-    return SDDF_ERR_OK;
+    return SDDF_LWIP_ERR_OK;
 }
 
 void sddf_lwip_process_rx(void)

From f98391f60f9640f48fe32825c9a8299f7ad949a1 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Thu, 19 Sep 2024 19:24:12 +1000
Subject: [PATCH 16/18] Unify channel naming

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/examples/echo_server/echo.c b/examples/echo_server/echo.c
index 49da1147e..45c81299c 100644
--- a/examples/echo_server/echo.c
+++ b/examples/echo_server/echo.c
@@ -20,7 +20,7 @@
 #include "echo.h"
 
 #define SERIAL_TX_CH 0
-#define TIMER  1
+#define TIMER_CH  1
 #define RX_CH  2
 #define TX_CH  3
 
@@ -59,7 +59,7 @@ void netif_status_callback(char *ip_addr)
  */
 void set_timeout(void)
 {
-    sddf_timer_set_timeout(TIMER, LWIP_TICK_MS * NS_IN_MS);
+    sddf_timer_set_timeout(TIMER_CH, LWIP_TICK_MS * NS_IN_MS);
 }
 
 /**
@@ -132,7 +132,7 @@ void init(void)
     net_queue_init(&net_tx_handle, tx_free, tx_active, tx_size);
     net_buffers_init(&net_tx_handle, 0);
 
-    sddf_lwip_init(net_rx_handle, net_tx_handle, RX_CH, TX_CH, rx_buffer_data_region, tx_buffer_data_region, TIMER,
+    sddf_lwip_init(net_rx_handle, net_tx_handle, RX_CH, TX_CH, rx_buffer_data_region, tx_buffer_data_region, TIMER_CH,
                    net_cli_mac_addr(microkit_name), NULL, netif_status_callback, enqueue_pbufs);
     set_timeout();
 
@@ -149,7 +149,7 @@ void notified(microkit_channel ch)
     case RX_CH:
         sddf_lwip_process_rx();
         break;
-    case TIMER:
+    case TIMER_CH:
         sddf_lwip_process_timeout();
         set_timeout();
         break;

From 7928c2987dbc37029dae602544b10c5bf0de4cf8 Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Thu, 19 Sep 2024 19:31:57 +1000
Subject: [PATCH 17/18] fix style

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 examples/echo_server/echo.c           |  7 ++--
 include/sddf/network/lib_sddf_lwip.h  | 13 +++----
 network/lib_sddf_lwip/lib_sddf_lwip.c | 49 ++++++++++-----------------
 3 files changed, 26 insertions(+), 43 deletions(-)

diff --git a/examples/echo_server/echo.c b/examples/echo_server/echo.c
index 45c81299c..6f9b3ffa0 100644
--- a/examples/echo_server/echo.c
+++ b/examples/echo_server/echo.c
@@ -92,8 +92,8 @@ void transmit(void)
         while (head != NULL && !net_queue_empty_free(&net_tx_handle)) {
             net_sddf_err_t err = sddf_lwip_transmit_pbuf(head);
             if (err == SDDF_LWIP_ERR_PBUF) {
-                sddf_dprintf("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
-                             head->tot_len, NET_BUFFER_SIZE);
+                sddf_dprintf("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n", head->tot_len,
+                             NET_BUFFER_SIZE);
             } else if (err != SDDF_LWIP_ERR_OK) {
                 sddf_dprintf("LWIP|ERROR: unkown error when trying to send pbuf %p\n", head);
             }
@@ -123,7 +123,8 @@ void transmit(void)
 
 void init(void)
 {
-    serial_cli_queue_init_sys(microkit_name, NULL, NULL, NULL, &serial_tx_queue_handle, serial_tx_queue, serial_tx_data);
+    serial_cli_queue_init_sys(microkit_name, NULL, NULL, NULL, &serial_tx_queue_handle, serial_tx_queue,
+                              serial_tx_data);
     serial_putchar_init(SERIAL_TX_CH, &serial_tx_queue_handle);
 
     size_t rx_size, tx_size;
diff --git a/include/sddf/network/lib_sddf_lwip.h b/include/sddf/network/lib_sddf_lwip.h
index 5b8dfea95..68e7a1b6c 100644
--- a/include/sddf/network/lib_sddf_lwip.h
+++ b/include/sddf/network/lib_sddf_lwip.h
@@ -24,9 +24,9 @@ typedef enum {
     /* No buffers available. */
     SDDF_LWIP_ERR_NO_BUF = -2,
     /* Pbuf successfully enqueued to be sent later. */
-    SDDF_LWIP_ERR_ENQUEUED    = -3,
+    SDDF_LWIP_ERR_ENQUEUED = -3,
     /* Could not resolve error. */
-    SDDF_LWIP_ERR_UNHANDLED    = -4
+    SDDF_LWIP_ERR_UNHANDLED = -4
 } net_sddf_err_t;
 
 /**
@@ -104,11 +104,8 @@ void sddf_lwip_maybe_notify(void);
  * handling function for no available sDDF TX buffers during sending of LWIP
  * pbuf. Provide NULL to leave unhandled.
  */
-void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
-                    microkit_channel rx_ch, microkit_channel tx_ch,
-                    uintptr_t rx_buffer_data_region,
-                    uintptr_t tx_buffer_data_region,
-                    microkit_channel timer_ch,
-                    uint64_t mac, sddf_lwip_err_output_fn err_output,
+void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue, microkit_channel rx_ch,
+                    microkit_channel tx_ch, uintptr_t rx_buffer_data_region, uintptr_t tx_buffer_data_region,
+                    microkit_channel timer_ch, uint64_t mac, sddf_lwip_err_output_fn err_output,
                     sddf_lwip_netif_status_callback_fn netif_callback,
                     sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free);
diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index f56304301..e8b2342bf 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -64,12 +64,7 @@ typedef struct pbuf_custom_offset {
     uint64_t offset;
 } pbuf_custom_offset_t;
 
-LWIP_MEMPOOL_DECLARE(
-    RX_POOL,
-    SDDF_LWIP_NUM_BUFS * 2,
-    sizeof(struct pbuf_custom_offset),
-    "Zero-copy RX pool"
-);
+LWIP_MEMPOOL_DECLARE(RX_POOL, SDDF_LWIP_NUM_BUFS * 2, sizeof(struct pbuf_custom_offset), "Zero-copy RX pool");
 
 lwip_state_t lwip_state;
 sddf_state_t sddf_state;
@@ -109,9 +104,8 @@ static void netif_status_callback_default(char *ip_addr)
     uint8_t *mac = lwip_state.netif.hwaddr;
     lwip_state.err_output("LWIP|NOTICE: DHCP request for mac "
                           "%02x:%02x:%02x:%02x:%02x:%02x "
-                          "returned ip address: %s\n", mac[0],
-                          mac[1], mac[2], mac[3], mac[4], mac[5],
-                          ip_addr);
+                          "returned ip address: %s\n",
+                          mac[0], mac[1], mac[2], mac[3], mac[4], mac[5], ip_addr);
 }
 
 /**
@@ -150,7 +144,7 @@ static void interface_free_buffer(struct pbuf *p)
     SYS_ARCH_DECL_PROTECT(old_level);
     pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *)p;
     SYS_ARCH_PROTECT(old_level);
-    net_buff_desc_t buffer = {custom_pbuf_offset->offset, 0};
+    net_buff_desc_t buffer = { custom_pbuf_offset->offset, 0 };
     int err = net_enqueue_free(&(sddf_state.rx_queue), buffer);
     assert(!err);
     sddf_state.notify_rx = true;
@@ -168,18 +162,12 @@ static void interface_free_buffer(struct pbuf *p)
  */
 static struct pbuf *create_interface_buffer(uint64_t offset, size_t length)
 {
-    pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *) LWIP_MEMPOOL_ALLOC(RX_POOL);
+    pbuf_custom_offset_t *custom_pbuf_offset = (pbuf_custom_offset_t *)LWIP_MEMPOOL_ALLOC(RX_POOL);
     custom_pbuf_offset->offset = offset;
     custom_pbuf_offset->custom.custom_free_function = interface_free_buffer;
 
-    return pbuf_alloced_custom(
-               PBUF_RAW,
-               length,
-               PBUF_REF,
-               &custom_pbuf_offset->custom,
-               (void *)(offset + sddf_state.rx_buffer_data_region),
-               NET_BUFFER_SIZE
-           );
+    return pbuf_alloced_custom(PBUF_RAW, length, PBUF_REF, &custom_pbuf_offset->custom,
+                               (void *)(offset + sddf_state.rx_buffer_data_region), NET_BUFFER_SIZE);
 }
 
 /**
@@ -196,8 +184,8 @@ static struct pbuf *create_interface_buffer(uint64_t offset, size_t length)
 static err_t lwip_eth_send(struct netif *netif, struct pbuf *p)
 {
     if (p->tot_len > NET_BUFFER_SIZE) {
-        lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
-                              p->tot_len, NET_BUFFER_SIZE);
+        lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n", p->tot_len,
+                              NET_BUFFER_SIZE);
         return ERR_MEM;
     }
 
@@ -228,8 +216,8 @@ static err_t lwip_eth_send(struct netif *netif, struct pbuf *p)
 net_sddf_err_t sddf_lwip_transmit_pbuf(struct pbuf *p)
 {
     if (p->tot_len > NET_BUFFER_SIZE) {
-        lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n",
-                              p->tot_len, NET_BUFFER_SIZE);
+        lwip_state.err_output("LWIP|ERROR: attempted to send a packet of size %u > BUFFER SIZE %u\n", p->tot_len,
+                              NET_BUFFER_SIZE);
         return SDDF_LWIP_ERR_PBUF;
     }
 
@@ -307,12 +295,9 @@ static void netif_status_callback(struct netif *netif)
     }
 }
 
-void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
-                    microkit_channel rx_ch, microkit_channel tx_ch,
-                    uintptr_t rx_buffer_data_region,
-                    uintptr_t tx_buffer_data_region,
-                    microkit_channel timer_ch,
-                    uint64_t mac, sddf_lwip_err_output_fn err_output,
+void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue, microkit_channel rx_ch,
+                    microkit_channel tx_ch, uintptr_t rx_buffer_data_region, uintptr_t tx_buffer_data_region,
+                    microkit_channel timer_ch, uint64_t mac, sddf_lwip_err_output_fn err_output,
                     sddf_lwip_netif_status_callback_fn netif_callback,
                     sddf_lwip_handle_empty_tx_free_fn handle_empty_tx_free)
 {
@@ -329,7 +314,8 @@ void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
     lwip_state.mac = mac;
     lwip_state.err_output = (err_output == NULL) ? sddf_printf_ : err_output;
     lwip_state.netif_callback = (netif_callback == NULL) ? netif_status_callback_default : netif_callback;
-    lwip_state.handle_empty_tx_free = (handle_empty_tx_free == NULL) ? handle_empty_tx_free_default : handle_empty_tx_free;
+    lwip_state.handle_empty_tx_free = (handle_empty_tx_free == NULL) ? handle_empty_tx_free_default
+                                                                     : handle_empty_tx_free;
 
     lwip_init();
 
@@ -345,8 +331,7 @@ void sddf_lwip_init(net_queue_handle_t rx_queue, net_queue_handle_t tx_queue,
     lwip_state.netif.name[0] = 'e';
     lwip_state.netif.name[1] = '0';
 
-    if (!netif_add(&(lwip_state.netif), &ipaddr, &netmask, &gw, (void *)&lwip_state,
-                   ethernet_init, ethernet_input)) {
+    if (!netif_add(&(lwip_state.netif), &ipaddr, &netmask, &gw, (void *)&lwip_state, ethernet_init, ethernet_input)) {
         lwip_state.err_output("LWIP|ERROR: Netif add returned NULL\n");
     }
 

From b5983a0388f2394851f1e24a201ce7edff2bf3cd Mon Sep 17 00:00:00 2001
From: Courtney Darville <courtneydarville94@outlook.com>
Date: Thu, 19 Sep 2024 19:40:42 +1000
Subject: [PATCH 18/18] Fix forgotten name update

Signed-off-by: Courtney Darville <courtneydarville94@outlook.com>
---
 network/lib_sddf_lwip/lib_sddf_lwip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/network/lib_sddf_lwip/lib_sddf_lwip.c b/network/lib_sddf_lwip/lib_sddf_lwip.c
index e8b2342bf..349e3eea4 100644
--- a/network/lib_sddf_lwip/lib_sddf_lwip.c
+++ b/network/lib_sddf_lwip/lib_sddf_lwip.c
@@ -83,7 +83,7 @@ static err_t sddf_err_to_lwip_err(net_sddf_err_t sddf_err)
         return ERR_OK;
     case SDDF_LWIP_ERR_PBUF:
         return ERR_BUF;
-    case SDDF_ERR_NO_BUF:
+    case SDDF_LWIP_ERR_NO_BUF:
         return ERR_MEM;
     case SDDF_LWIP_ERR_ENQUEUED:
         return ERR_OK;