Files
RTLPlayground/rtl837x_trap.h
DrDoof 14b2ce1c49 trap: deliver reserved multicast to the CPU by trap, STP first
A reserved-multicast trap goes to the port named in EXT_CPU_CTRL, which
names no port out of reset, so trapped frames were dropped at ingress.
trap_init() points it at the CPU port once at startup, and
trap_rma_set() changes only the action field of an RMA register.

A trapped frame arrives without the VLAN tag a forwarded one gets, so
TRAP_RX_BODY() gives the offset of the payload for both forms.

STP now traps its address while it runs instead of steering it with a
static L2 entry per VLAN, so turning it on no longer walks the VLAN
table and a pvid change no longer needs stp off and on. With STP off
the flooding entries are restored as before.

A trapped BPDU passes the tagged-only ingress filter that drops a
forwarded one, so the stp_setup() warning about such ports goes.
2026-10-12 01:16:28 +02:00

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C

#ifndef _RTL837X_TRAP_H_
#define _RTL837X_TRAP_H_
#include <stdint.h>
#include "rtl837x_common.h"
#define TRAP_RX_HDR_SIZE (12 + RTL_TAG_SIZE)
#define TRAP_RX_BODY() \
((uip_buf[TRAP_RX_HDR_SIZE] == 0x81 && uip_buf[TRAP_RX_HDR_SIZE + 1] == 0x00) \
? TRAP_RX_HDR_SIZE + VLAN_TAG_SIZE : TRAP_RX_HDR_SIZE)
void trap_init(void) __banked;
void trap_rma_set(uint16_t reg, uint8_t act) __banked;
#endif