Enable IPv4 or IPv4/IPv6 stacks, Ethernet class (#695)

IPv4-only mode saves 20KB+ of flash memory.

Add some backwards compatibility with the global Arduino Ethernet
class when running in IPv4 only mode.

Fixes #687

* Speed P.IO build by not cloning 2GB of sources
* Document P.IO new option

Author: earlephilhower

.github/workflows/pull-request.yml

@@ -185,7 +185,14 @@ jobs:
     steps:
     - uses: actions/checkout@v3
       with:
-        submodules: 'recursive'
+        submodules: 'true'
+    - name: Initialize needed submodules
+      run: |
+        cd pico-sdk
+        git submodule update --init
+        cd ../libraries/Adafruit_TinyUSB_Arduino
+        git submodule update --init
+        cd ../..
     - name: Cache pip
       uses: actions/cache@v2
       with:

boards.txt

@@ -179,8 +179,10 @@ bool IPAddress::isValid(const char* arg) {
 	return IPAddress().fromString(arg);
 }
 
+namespace arduino {
 const IPAddress INADDR_ANY; // generic "0.0.0.0" for IPv4 & IPv6
 const IPAddress INADDR_NONE(255,255,255,255);
+};
 
 void IPAddress::clear() {
     (*this) = INADDR_ANY;

cores/rp2040/api/IPAddress.cpp

@@ -27,11 +27,14 @@
 #include <lwip/ip_addr.h>
 #include <lwip/ip4_addr.h>
 
-namespace arduino {
 
-#if !LWIP_IPV6
-struct ip_addr: ipv4_addr { };
-#endif // !LWIP_IPV6
+// forward declarations of global name space friend classes
+class EthernetClass;
+class DhcpClass;
+class DNSClient;
+
+
+namespace arduino {
 
 // to display a netif id with printf:
 #define NETIFID_STR        "%c%c%u"
@@ -48,8 +51,19 @@ struct ip_addr: ipv4_addr { };
 
 class IPAddress: public Printable {
     private:
-
+#if !LWIP_IPV6
+        // Ugly hack to allow Arduino Ethernet library to twiddle internal bits.
+        // This can only work in IPv4-only mode, of course.
+        union {
+            ip_addr_t _ip;
+            struct {
+                uint8_t bytes[4];
+            } _address;
+        };
+        static_assert(sizeof(_ip) == sizeof(_address), "IP_ADDR_T size != _ADDRESS size");
+#else
         ip_addr_t _ip;
+#endif
 
         // Access the raw byte array containing the address.  Because this returns a pointer
         // to the internal structure rather than a copy of the address this function should only
@@ -149,6 +163,10 @@ class IPAddress: public Printable {
         friend class DhcpClass;
         friend class DNSClient;
 
+        friend ::EthernetClass;
+        friend ::DhcpClass;
+        friend ::DNSClient;
+
         /*
                lwIP address compatibility
         */
@@ -167,14 +185,14 @@ class IPAddress: public Printable {
 
         bool isLocal () const { return ip_addr_islinklocal(&_ip); }
 
-#if LWIP_IPV6
 
         IPAddress(const ip_addr_t& lwip_addr) { ip_addr_copy(_ip, lwip_addr); }
         IPAddress(const ip_addr_t* lwip_addr) { ip_addr_copy(_ip, *lwip_addr); }
 
         IPAddress& operator=(const ip_addr_t& lwip_addr) { ip_addr_copy(_ip, lwip_addr); return *this; }
         IPAddress& operator=(const ip_addr_t* lwip_addr) { ip_addr_copy(_ip, *lwip_addr); return *this; }
 
+#if LWIP_IPV6
         uint16_t* raw6()
         {
             setV6();

cores/rp2040/api/IPAddress.h

@@ -222,6 +222,18 @@ default Pico SDK USB stack. To change it, add
 Note that the special "No USB" setting is also supported, through the
 shortcut-define ``PIO_FRAMEWORK_ARDUINO_NO_USB``.
 
+IP Stack
+---------
+
+The lwIP stack can be configured to support only IPv4 (default) or additionally IPv6. To activate IPv6 support, add 
+
+.. code:: ini
+
+    ; IPv6
+    build_flags = -DPIO_FRAMEWORK_ARDUINO_ENABLE_IPV6
+
+to the ``platformio.ini``.
+
 
 Selecting a different core version
 ----------------------------------

docs/platformio.rst

@@ -179,7 +179,7 @@ int LwipIntfDev<RawDev>::hostByName(const char* aHostname, IPAddress& aResult, i
 #if LWIP_IPV4 && LWIP_IPV6
     err_t err = dns_gethostbyname_addrtype(aHostname, &addr, &_dns_found_callback, &cb, LWIP_DNS_ADDRTYPE_DEFAULT);
 #else
-    err_t err = dns_gethostbyname(aHostname, &addr, &wifi_dns_found_callback, &cb);
+    err_t err = dns_gethostbyname(aHostname, &addr, &_dns_found_callback, &cb);
 #endif
     if (err == ERR_OK) {
         aResult = IPAddress(&addr);

lib/libpico-ipv6.a

@@ -41,12 +41,11 @@ compiler.warning_flags.default=-Werror=return-type
 compiler.warning_flags.more=-Wall -Werror=return-type -Wno-ignored-qualifiers
 compiler.warning_flags.all=-Wall -Wextra -Werror=return-type -Wno-ignored-qualifiers
 
-compiler.netdefines=-DPICO_CYW43_ARCH_THREADSAFE_BACKGROUND=1 -DCYW43_LWIP=0 -DLWIP_IPV6=1 -DLWIP_IPV4=1 -DLWIP_IGMP=1 -DLWIP_CHECKSUM_CTRL_PER_NETIF=1
+compiler.netdefines=-DPICO_CYW43_ARCH_THREADSAFE_BACKGROUND=1 -DCYW43_LWIP=0 {build.lwipdefs} -DLWIP_IGMP=1 -DLWIP_CHECKSUM_CTRL_PER_NETIF=1
 compiler.defines={build.led} {build.usbstack_flags} -DCFG_TUSB_MCU=OPT_MCU_RP2040 -DUSB_VID={build.vid} -DUSB_PID={build.pid} '-DUSB_MANUFACTURER={build.usb_manufacturer}' '-DUSB_PRODUCT={build.usb_product}' {compiler.netdefines}
 compiler.includes="-iprefix{runtime.platform.path}/" "@{runtime.platform.path}/lib/platform_inc.txt" "-I{runtime.platform.path}/include"
 compiler.flags=-march=armv6-m -mcpu=cortex-m0plus -mthumb -ffunction-sections -fdata-sections {build.flags.exceptions} {build.flags.stackprotect}
 compiler.wrap="@{runtime.platform.path}/lib/platform_wrap.txt"
-compiler.libpico="{runtime.platform.path}/lib/libpico.a"
 compiler.libbearssl="{runtime.platform.path}/lib/libbearssl.a"
 
 compiler.c.cmd=arm-none-eabi-gcc
@@ -92,8 +91,9 @@ build.usbstack_flags=
 build.flags.libstdcpp=-lstdc++
 build.flags.exceptions=-fno-exceptions
 build.flags.stackprotect=
-
+build.libpico=libpico.a
 build.boot2=boot2_generic_03h_4_padded_checksum
+build.lwipdefs=-DLWIP_IPV6=0 -DLWIP_IPV4=1
 
 # Allow Pico boards do be auto-discovered by the IDE
 discovery.rp2040.pattern="{runtime.tools.pqt-python3.path}/python3" -I "{runtime.platform.path}/tools/discovery.py"
@@ -123,7 +123,7 @@ recipe.hooks.linking.prelink.1.pattern="{runtime.tools.pqt-python3.path}/python3
 recipe.hooks.linking.prelink.2.pattern="{compiler.path}{compiler.S.cmd}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} -c "{runtime.platform.path}/boot2/{build.boot2}.S" "-I{runtime.platform.path}/pico-sdk/src/rp2040/hardware_regs/include/" "-I{runtime.platform.path}/pico-sdk/src/common/pico_binary_info/include" -o "{build.path}/boot2.o"
 
 ## Combine gc-sections, archives, and objects
-recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" "-L{build.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} {compiler.ldflags} "-Wl,--script={build.path}/memmap_default.ld" "-Wl,-Map,{build.path}/{build.project_name}.map" -o "{build.path}/{build.project_name}.elf" -Wl,--start-group {object_files} "{build.path}/{archive_file}" "{build.path}/boot2.o" {compiler.libraries.ldflags} {compiler.libpico} {compiler.libbearssl} -lm -lc {build.flags.libstdcpp} -lc -Wl,--end-group
+recipe.c.combine.pattern="{compiler.path}{compiler.c.elf.cmd}" "-L{build.path}" {compiler.c.elf.flags} {compiler.c.elf.extra_flags} {compiler.ldflags} "-Wl,--script={build.path}/memmap_default.ld" "-Wl,-Map,{build.path}/{build.project_name}.map" -o "{build.path}/{build.project_name}.elf" -Wl,--start-group {object_files} "{build.path}/{archive_file}" "{build.path}/boot2.o" {compiler.libraries.ldflags} "{runtime.platform.path}/lib/{build.libpico}" {compiler.libbearssl} -lm -lc {build.flags.libstdcpp} -lc -Wl,--end-group
 
 ## Create output (UF2 file)
 recipe.objcopy.uf2.pattern="{runtime.tools.pqt-elf2uf2.path}/elf2uf2" "{build.path}/{build.project_name}.elf" "{build.path}/{build.project_name}.uf2"

lib/libpico.a

@@ -21,7 +21,7 @@ target_compile_definitions(pico PUBLIC
 	PICO_FLASH_SIZE_BYTES=16777216
 	PICO_XOSC_STARTUP_DELAY_MULTIPLIER=64
         LWIP_IPV4=1
-        LWIP_IPV6=1
+        LWIP_IPV6=${IPV6}
         LWIP_UDP=1
         LWIP_IGMP=1
         LWIP_CHECKSUM_CTRL_PER_NETIF=1