ProtoCore v0.0.1
Deterministic, zero-heap network stack for embedded targets
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IPv6 - serve over IPv6 (dual-stack)

Layer: Foundation · Build flags: PC_ENABLE_IPV6

What this example teaches

The server is already dual-stack: the TCP and UDP listeners bind IPADDR_TYPE_ANY, so the moment the interface has an IPv6 address it answers over v6 as well as v4. All you add is turning IPv6 on for the network interface:

init_wifi_physical(SSID, PASSWORD);
while (!wifi_ready()) delay(250);
init_ipv6_physical(); // enable IPv6 (SLAAC) on the Wi-Fi netif
while (!pc_ipv6_ready()) delay(250); // waits for a global (routable) v6 address
init_wifi_physical
bool init_wifi_physical(const char *, const char *)
Connect to a WiFi access point.
Definition physical.cpp:41
pc_ipv6_ready
bool pc_ipv6_ready(void)
True once the interface has a global IPv6 address (see net_global_ipv6()).
Definition physical.cpp:73
wifi_ready
bool wifi_ready()
True if the WiFi station link is up (associated + an IP is assigned).
Definition physical.cpp:45
init_ipv6_physical
bool init_ipv6_physical(void)
Enable IPv6 (dual-stack) on the Wi-Fi interface (PC_ENABLE_IPV6).
Definition physical.cpp:65

PC_ENABLE_IPV6 gates the bring-up. init_ipv6_physical() enables IPv6 on the netif (SLAAC gives a fe80:: link-local address, plus a global one if a router advertises a prefix). net_global_ipv6() reads the acquired global address straight from lwIP into a pc_ip.

The pc_ip address core

network_drivers/network/ip.h is one family-tagged type for both v4 and v6, with:

  • **pc_ip_parse()** - RFC 4291 text (dotted-quad; v6 with :: zero-compression and the embedded-v4 ::ffff:a.b.c.d tail).
  • **pc_ip_format()** - the RFC 5952 canonical form (lower-case, no leading zeros, longest zero run compressed, v4-mapped shown dotted).
  • **pc_ip_classify()** - loopback / link-local / private-ULA / multicast / global.

It is pure and host-tested (pio test -e native_ip), so the address handling is verified off-device; the netif bring-up is ESP32-only.

Try it

Flash, open Serial @ 115200 for the addresses, then (note the brackets and curl -g):

curl -g "http://[2001:db8::abcd]/" # your printed global address

Build-flag note

The flag must reach the whole library build:

pio ci --board=esp32dev --project-option="framework=arduino" \
--project-option="build_flags=-DPC_ENABLE_IPV6=1" \
--lib="." examples/Foundation/IPv6/IPv6.ino

Requires an lwIP built with LWIP_IPV6=1 (the stock Arduino-ESP32 core ships it). In the Arduino IDE the build_opt.h beside this sketch sets the flag for you.