lwIP (Raw API)

Platform/LwipRaw/ wraps the Raw API of lwIP (lwIP documentation). Its .c files compile against your lwipopts.h, so the adapter inherits your stack's configuration.

Fills the Resolver, Datagram and Stream roles, plus the address handle they share. Layer Mbed TLS over the TCP stream for TLS.

What it ships

Class	Role
SolidSyslogLwipRawAddress	destination handle
SolidSyslogLwipRawResolver	numeric IPv4 resolver
SolidSyslogLwipRawDnsResolver	DNS resolver (LWIP_DNS=1)
SolidSyslogLwipRawDatagram	UDP sender
SolidSyslogLwipRawTcpStream	TCP byte transport

The source calls lwIP only — no direct OS calls. The TCP stream's synchronous Open needs a bounded sleep, injected as a SolidSyslogSleepFunction.

The marshal

Not a role: SolidSyslogLwipRaw_SetMarshal is a process-global seam, not a component you wire into the config. Every lwIP call the Datagram and TcpStream make is routed through one marshal hop.

• NO_SYS=1 — bare metal, one execution context. Do nothing; the default direct-call marshal is correct.
• NO_SYS=0 — an RTOS tcpip thread (lwIP multithreading documentation). Call SolidSyslogLwipRaw_SetMarshal(fn) once at boot, before creating any adapter, passing a function that runs its callback on the core-owning thread.

The marshal must invoke its callback synchronously — the adapter reads results the moment the hop returns. tcpip_callback_with_block(…, 1) or a LOCK_TCPIP_CORE / UNLOCK_TCPIP_CORE pair satisfy that; a bare tcpip_callback does not. Worked example: Bdd/Targets/FreeRtosLwip/main.c.

Requirements

Your lwipopts.h must enable the features the adapter wraps:

Setting	For
LWIP_RAW=1	the Raw API
LWIP_UDP=1	the UDP datagram
LWIP_TCP=1	the TCP stream
LWIP_DNS=1	the DNS resolver only

Also set ARP_QUEUEING=1 (else the first datagram to an unresolved peer is dropped) and LWIP_TCP_KEEPALIVE=1, and size PBUF_POOL_SIZE / MEMP_NUM_TCP_PCB / MEMP_NUM_UDP_PCB to your instance counts.

Full setup — config, marshal, DNS — is Integrating lwIP.