// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright (c) 2026 Robin Jarry

#include "if_map.h"
#include "l3vni_map.h"

#include <gr_infra.h>

#include <lib/jhash.h>
#include <lib/typesafe.h>

// All functions in this file run exclusively on the dplane thread
// (grout_link_change, grout_add_nexthop, grout_neigh_update_ctx).
// No locking required.

// VRF -> VXLAN iface mapping ///////////////////////////////////////////////////

PREDECL_HASH(l3vni_hash);

struct l3vni_entry {
	struct l3vni_hash_item item;
	uint16_t vrf_id;
	uint16_t vxlan_iface_id;
};

static int l3vni_cmp(const struct l3vni_entry *a, const struct l3vni_entry *b) {
	return numcmp(a->vrf_id, b->vrf_id);
}

static uint32_t l3vni_hashfn(const struct l3vni_entry *e) {
	return e->vrf_id;
}

DECLARE_HASH(l3vni_hash, struct l3vni_entry, item, l3vni_cmp, l3vni_hashfn);
static struct l3vni_hash_head l3vni_entries = INIT_HASH(l3vni_entries);

void l3vni_set(uint16_t vrf_id, uint16_t vxlan_iface_id) {
	struct l3vni_entry *e, key = {.vrf_id = vrf_id};

	e = l3vni_hash_find(&l3vni_entries, &key);
	if (e != NULL) {
		e->vxlan_iface_id = vxlan_iface_id;
		return;
	}
	e = XCALLOC(MTYPE_GROUT_MEM, sizeof(*e));
	e->vrf_id = vrf_id;
	e->vxlan_iface_id = vxlan_iface_id;
	l3vni_hash_add(&l3vni_entries, e);
}

void l3vni_del(uint16_t vrf_id) {
	struct l3vni_entry key = {.vrf_id = vrf_id};
	struct l3vni_entry *e = l3vni_hash_find(&l3vni_entries, &key);

	if (e != NULL) {
		l3vni_hash_del(&l3vni_entries, e);
		XFREE(MTYPE_GROUT_MEM, e);
	}
}

void l3vni_del_iface(uint16_t iface_id) {
	struct l3vni_entry *e;

	frr_each_safe(l3vni_hash, &l3vni_entries, e) {
		if (e->vxlan_iface_id == iface_id) {
			l3vni_hash_del(&l3vni_entries, e);
			XFREE(MTYPE_GROUT_MEM, e);
			return;
		}
	}
}

uint16_t l3vni_get_vxlan(uint16_t vrf_id) {
	struct l3vni_entry key = {.vrf_id = vrf_id};
	struct l3vni_entry *e = l3vni_hash_find(&l3vni_entries, &key);
	return e ? e->vxlan_iface_id : GR_IFACE_ID_UNDEF;
}

// (VRF, VTEP) -> RMAC cache ///////////////////////////////////////////////////

PREDECL_HASH(rmac_hash);

struct rmac_entry {
	struct rmac_hash_item item;
	uint16_t vrf_id;
	struct ipaddr vtep;
	struct ethaddr mac;
};

static int rmac_cmp(const struct rmac_entry *a, const struct rmac_entry *b) {
	int v = numcmp(a->vrf_id, b->vrf_id);
	if (v != 0)
		return v;

	int t = numcmp(a->vtep.ipa_type, b->vtep.ipa_type);
	if (t != 0)
		return t;

	switch (a->vtep.ipa_type) {
	case IPADDR_V4:
		return numcmp(a->vtep.ipaddr_v4.s_addr, b->vtep.ipaddr_v4.s_addr);
	case IPADDR_V6:
		return memcmp(&a->vtep.ipaddr_v6, &b->vtep.ipaddr_v6, sizeof(a->vtep.ipaddr_v6));
	default:
		break;
	}
	return 0;
}

static uint32_t rmac_hashfn(const struct rmac_entry *e) {
	uint32_t h = jhash_2words(e->vrf_id, e->vtep.ipa_type, 0);

	switch (e->vtep.ipa_type) {
	case IPADDR_V4:
		h = jhash_1word(e->vtep.ipaddr_v4.s_addr, h);
		break;
	case IPADDR_V6:
		h = jhash(&e->vtep.ipaddr_v6, sizeof(e->vtep.ipaddr_v6), h);
	default:
		break;
	}

	return h;
}

DECLARE_HASH(rmac_hash, struct rmac_entry, item, rmac_cmp, rmac_hashfn);
static struct rmac_hash_head rmac_entries = INIT_HASH(rmac_entries);

static void rmac_vtep_entry(const struct ipaddr *vtep, struct ipaddr *key) {
	*key = *vtep;

	if (vtep->ipa_type == IPADDR_V6 && IS_MAPPED_IPV6(&vtep->ipaddr_v6)) {
		struct in_addr v4;

		ipv4_mapped_ipv6_to_ipv4(&vtep->ipaddr_v6, &v4);
		memset(key, 0, sizeof(*key));
		key->ipa_type = IPADDR_V4;
		key->ipaddr_v4 = v4;
	}
}

void l3vni_rmac_set(uint16_t vrf_id, const struct ipaddr *vtep, const struct ethaddr *mac) {
	struct rmac_entry *e, key = {.vrf_id = vrf_id};
	rmac_vtep_entry(vtep, &key.vtep);

	e = rmac_hash_find(&rmac_entries, &key);
	if (e != NULL) {
		e->mac = *mac;
		return;
	}
	e = XCALLOC(MTYPE_GROUT_MEM, sizeof(*e));
	e->vrf_id = vrf_id;
	e->vtep = key.vtep;
	e->mac = *mac;
	rmac_hash_add(&rmac_entries, e);
}

void l3vni_rmac_del(uint16_t vrf_id, const struct ipaddr *vtep) {
	struct rmac_entry key = {.vrf_id = vrf_id};
	rmac_vtep_entry(vtep, &key.vtep);

	struct rmac_entry *e = rmac_hash_find(&rmac_entries, &key);

	if (e != NULL) {
		rmac_hash_del(&rmac_entries, e);
		XFREE(MTYPE_GROUT_MEM, e);
	}
}

const struct ethaddr *l3vni_rmac_get(uint16_t vrf_id, const struct ipaddr *vtep) {
	struct rmac_entry key = {.vrf_id = vrf_id};
	rmac_vtep_entry(vtep, &key.vtep);
	struct rmac_entry *e = rmac_hash_find(&rmac_entries, &key);
	return e ? &e->mac : NULL;
}
