From 5af7fdf330ad2d3cf4453eff8588c18cd7d2a64c Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Sat, 5 Aug 2023 17:08:52 +1000
Subject: [PATCH] AP_Networking: use host byte order addresses internally

this should make the lua API easier to handle, as it can manipulate
uint32_t easily
---
 libraries/AP_Networking/AP_Networking.cpp     | 30 +++++--------------
 libraries/AP_Networking/AP_Networking.h       |  5 ++--
 .../AP_Networking/AP_Networking_ChibiOS.cpp   | 12 ++++----
 .../AP_Networking/AP_Networking_address.cpp   |  8 ++---
 4 files changed, 18 insertions(+), 37 deletions(-)

diff --git a/libraries/AP_Networking/AP_Networking.cpp b/libraries/AP_Networking/AP_Networking.cpp
index 9ff4d1da83..c5004e0fb4 100644
--- a/libraries/AP_Networking/AP_Networking.cpp
+++ b/libraries/AP_Networking/AP_Networking.cpp
@@ -142,14 +142,10 @@ void AP_Networking::update()
 
 uint32_t AP_Networking::convert_netmask_bitcount_to_ip(const uint32_t netmask_bitcount)
 {
-    if (netmask_bitcount > 32) {
-        return 0;
+    if (netmask_bitcount >= 32) {
+        return 0xFFFFFFFFU;
     }
-    uint32_t netmask_ip = 0;
-    for (uint32_t i=0; i<netmask_bitcount; i++) {
-        netmask_ip |= (1UL << i);
-    }
-    return netmask_ip;
+    return ~((1U<<(32U-netmask_bitcount))-1U);
 }
 
 uint8_t AP_Networking::convert_netmask_ip_to_bitcount(const uint32_t netmask_ip)
@@ -169,29 +165,17 @@ uint32_t AP_Networking::convert_str_to_ip(const char* ip_str)
 {
     uint32_t ip = 0;
     inet_pton(AF_INET, ip_str, &ip);
-    return ip;
+    return ntohl(ip);
 }
 
-const char* AP_Networking::convert_ip_to_str(const uint8_t ip[4])
+const char* AP_Networking::convert_ip_to_str(uint32_t ip)
 {
+    ip = htonl(ip);
     static char _str_buffer[20];
-    if (hal.util->snprintf(_str_buffer, sizeof(_str_buffer), "%u.%u.%u.%u", (unsigned)ip[0], (unsigned)ip[1], (unsigned)ip[2], (unsigned)ip[3]) == 0) {
-        _str_buffer[0] = '\0';
-    }
+    inet_ntop(AF_INET, &ip, _str_buffer, sizeof(_str_buffer));
     return _str_buffer;
 }
 
-const char* AP_Networking::convert_ip_to_str(const uint32_t ip)
-{
-    uint8_t ip_array[4];
-    ip_array[3] = ((ip >> 24) & 0xff);
-    ip_array[2] = ((ip >> 16) & 0xff);
-    ip_array[1] = ((ip >> 8) & 0xff);
-    ip_array[0] = (ip & 0xff);
-
-    return convert_ip_to_str(ip_array);
-}
-
 /*
   convert a string to an ethernet MAC address
  */
diff --git a/libraries/AP_Networking/AP_Networking.h b/libraries/AP_Networking/AP_Networking.h
index f0b4fdb17e..0a5628c97e 100644
--- a/libraries/AP_Networking/AP_Networking.h
+++ b/libraries/AP_Networking/AP_Networking.h
@@ -11,7 +11,7 @@
 #include "AP_Networking_backend.h"
 
 /*
-  Note! all uint32_t IPv4 addresses are in network byte order (big-endian)
+  Note! all uint32_t IPv4 addresses are in host byte order
 */
 
 class AP_Networking
@@ -145,8 +145,7 @@ public:
 
     // helper functions to convert between 32bit IP addresses and null terminated strings and back
     static uint32_t convert_str_to_ip(const char* ip_str);
-    static const char* convert_ip_to_str(const uint8_t ip[4]);
-    static const char* convert_ip_to_str(const uint32_t ip);
+    static const char* convert_ip_to_str(uint32_t ip);
 
     // convert string to ethernet mac address
     static bool convert_str_to_macaddr(const char *mac_str, uint8_t addr[6]);
diff --git a/libraries/AP_Networking/AP_Networking_ChibiOS.cpp b/libraries/AP_Networking/AP_Networking_ChibiOS.cpp
index c47bb3d6b2..6e65d13cf8 100644
--- a/libraries/AP_Networking/AP_Networking_ChibiOS.cpp
+++ b/libraries/AP_Networking/AP_Networking_ChibiOS.cpp
@@ -114,9 +114,9 @@ bool AP_Networking_ChibiOS::init()
         lwip_options->addrMode = NET_ADDRESS_DHCP;
     } else {
         lwip_options->addrMode = NET_ADDRESS_STATIC;
-        lwip_options->address = frontend.get_ip_param();
-        lwip_options->netmask = frontend.get_netmask_param();
-        lwip_options->gateway = frontend.get_gateway_param();
+        lwip_options->address = htonl(frontend.get_ip_param());
+        lwip_options->netmask = htonl(frontend.get_netmask_param());
+        lwip_options->gateway = htonl(frontend.get_gateway_param());
     }
     frontend.param.macaddr.get_address(macaddr);
     lwip_options->macaddress = macaddr;
@@ -131,9 +131,9 @@ bool AP_Networking_ChibiOS::init()
  */
 void AP_Networking_ChibiOS::update()
 {
-    const uint32_t ip = lwipGetIp();
-    const uint32_t nm = lwipGetNetmask();
-    const uint32_t gw = lwipGetGateway();
+    const uint32_t ip = ntohl(lwipGetIp());
+    const uint32_t nm = ntohl(lwipGetNetmask());
+    const uint32_t gw = ntohl(lwipGetGateway());
 
     if (ip != activeSettings.ip ||
         nm != activeSettings.nm ||
diff --git a/libraries/AP_Networking/AP_Networking_address.cpp b/libraries/AP_Networking/AP_Networking_address.cpp
index 386dac004c..675b9159f4 100644
--- a/libraries/AP_Networking/AP_Networking_address.cpp
+++ b/libraries/AP_Networking/AP_Networking_address.cpp
@@ -92,8 +92,6 @@ const AP_Param::GroupInfo AP_Networking_MAC::var_info[] = {
     AP_GROUPEND
 };
 
-
-
 /*
   IPV4 address parameter class
  */
@@ -107,8 +105,8 @@ uint32_t AP_Networking_IPV4::get_uint32(void) const
 {
     uint32_t v = 0;
     uint8_t *b = (uint8_t*)&v;
-    for (uint8_t i=0; i<ARRAY_SIZE(addr); i++) {
-        b[i] = uint8_t(addr[i].get());
+    for (uint8_t i=0; i<4; i++) {
+        b[3-i] = uint8_t(addr[i].get());
     }
     return v;
 }
@@ -117,7 +115,7 @@ void AP_Networking_IPV4::set_default_uint32(uint32_t v)
 {
     uint8_t *b = (uint8_t*)&v;
     for (uint8_t i=0; i<ARRAY_SIZE(addr); i++) {
-        addr[i].set_default(b[i]);
+        addr[3-i].set_default(b[i]);
     }
 }