// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) 1997, 2000
 * Portions:
 *   Swedish University of Agricultural Sciences
 *   Robert Olsson
 *   Kunihiro Ishiguro
 *
 * Thanks to Jens Laas at Swedish University of Agricultural Sciences
 * for reviewing and tests.
 */

#include <zebra.h>

#include "if.h"
#include "vty.h"
#include "sockunion.h"
#include "prefix.h"
#include "command.h"
#include "memory.h"
#include "stream.h"
#include "ioctl.h"
#include "connected.h"
#include "log.h"
#include "zclient.h"
#include "frrevent.h"
#include "lib_errors.h"
#include "zebra/interface.h"
#include "zebra/rtadv.h"
#include "zebra/rib.h"
#include "zebra/zebra_router.h"
#include "zebra/redistribute.h"
#include "zebra/irdp.h"
#include "zebra/zebra_errors.h"
#include <netinet/ip_icmp.h>
#include "if.h"
#include "sockunion.h"
#include "log.h"
#include "network.h"

extern int irdp_sock;

DEFINE_MTYPE_STATIC(ZEBRA, IRDP_IF, "IRDP interface data");

#define IRDP_CONFIGED                                                                 \
	do {                                                                          \
		if (!irdp) {                                                          \
			vty_out(vty,                                                  \
				"Please Configure IRDP before using this command\n"); \
			return CMD_WARNING_CONFIG_FAILED;                             \
		}                                                                     \
	} while (0)

static struct irdp_interface *irdp_if_get(struct interface *ifp)
{
	struct zebra_if *zi = ifp->info;

	if (!zi)
		return NULL;

	if (!zi->irdp)
		zi->irdp = XCALLOC(MTYPE_IRDP_IF, sizeof(*zi->irdp));

	if (!zi->irdp->started)
		return NULL;

	return zi->irdp;
}

static int irdp_if_delete(struct interface *ifp)
{
	struct zebra_if *zi = ifp->info;
	if (!zi)
		return 0;
	XFREE(MTYPE_IRDP_IF, zi->irdp);
	return 0;
}

static const char *inet_2a(uint32_t a, char *b, size_t b_len)
{
	snprintf(b, b_len, "%u.%u.%u.%u", (a)&0xFF, (a >> 8) & 0xFF,
		 (a >> 16) & 0xFF, (a >> 24) & 0xFF);
	return b;
}


static struct prefix *irdp_get_prefix(struct interface *ifp)
{
	struct connected *ifc;

	frr_each (if_connected, ifp->connected, ifc) {
		if (ifc->address->family == AF_INET)
			return ifc->address;
	}

	return NULL;
}

/* Join to the add/leave multicast group. */
static int if_group(struct interface *ifp, int sock, uint32_t group,
		    int add_leave)
{
	struct ip_mreq m;
	struct prefix *p;
	int ret;
	char b1[INET_ADDRSTRLEN];

	memset(&m, 0, sizeof(m));
	m.imr_multiaddr.s_addr = htonl(group);
	p = irdp_get_prefix(ifp);

	if (!p) {
		flog_warn(EC_ZEBRA_NO_IFACE_ADDR,
			  "IRDP: can't get address for %s", ifp->name);
		return 1;
	}

	m.imr_interface = p->u.prefix4;

	ret = setsockopt(sock, IPPROTO_IP, add_leave, (char *)&m,
			 sizeof(struct ip_mreq));
	if (ret < 0)
		flog_err_sys(EC_LIB_SOCKET, "IRDP: %s can't setsockopt %s: %s",
			     add_leave == IP_ADD_MEMBERSHIP ? "join group"
							    : "leave group",
			     inet_2a(group, b1, sizeof(b1)),
			     safe_strerror(errno));

	return ret;
}

static int if_add_group(struct interface *ifp)
{
	struct zebra_if *zi = ifp->info;
	struct irdp_interface *irdp = zi->irdp;
	int ret;
	char b1[INET_ADDRSTRLEN];

	if (!irdp)
		return -1;

	ret = if_group(ifp, irdp_sock, INADDR_ALLRTRS_GROUP, IP_ADD_MEMBERSHIP);
	if (ret < 0) {
		return ret;
	}

	if (irdp->flags & IF_DEBUG_MISC)
		zlog_debug("IRDP: Adding group %s for %s",
			   inet_2a(htonl(INADDR_ALLRTRS_GROUP), b1, sizeof(b1)),
			   ifp->name);
	return 0;
}

static int if_drop_group(struct interface *ifp)
{
	struct zebra_if *zi = ifp->info;
	struct irdp_interface *irdp = zi->irdp;
	int ret;
	char b1[INET_ADDRSTRLEN];

	if (!irdp)
		return -1;

	ret = if_group(ifp, irdp_sock, INADDR_ALLRTRS_GROUP,
		       IP_DROP_MEMBERSHIP);
	if (ret < 0)
		return ret;

	if (irdp->flags & IF_DEBUG_MISC)
		zlog_debug("IRDP: Leaving group %s for %s",
			   inet_2a(htonl(INADDR_ALLRTRS_GROUP), b1, sizeof(b1)),
			   ifp->name);
	return 0;
}

static void if_set_defaults(struct irdp_interface *irdp)
{
	irdp->MaxAdvertInterval = IRDP_MAXADVERTINTERVAL;
	irdp->MinAdvertInterval = IRDP_MINADVERTINTERVAL;
	irdp->Preference = IRDP_PREFERENCE;
	irdp->Lifetime = IRDP_LIFETIME;
}


static struct Adv *Adv_new(void)
{
	return XCALLOC(MTYPE_IRDP_IF, sizeof(struct Adv));
}

static void Adv_free(struct Adv *adv)
{
	XFREE(MTYPE_IRDP_IF, adv);
}

static void irdp_if_start(struct interface *ifp, int multicast,
			  int set_defaults)
{
	struct zebra_if *zi = ifp->info;
	struct irdp_interface *irdp = zi->irdp;
	struct connected *ifc;
	uint32_t timer, seed;

	assert(irdp);

	irdp->started = true;
	if (irdp->flags & IF_ACTIVE) {
		zlog_debug("IRDP: Interface is already active %s", ifp->name);
		return;
	}
	if ((irdp_sock < 0) && ((irdp_sock = irdp_sock_init()) < 0)) {
		flog_warn(EC_ZEBRA_IRDP_CANNOT_ACTIVATE_IFACE,
			  "IRDP: Cannot activate interface %s (cannot create IRDP socket)",
			  ifp->name);
		return;
	}
	irdp->flags |= IF_ACTIVE;

	if (!multicast)
		irdp->flags |= IF_BROADCAST;

	if_add_update(ifp);

	if (!(ifp->flags & IFF_UP)) {
		flog_warn(EC_ZEBRA_IRDP_IFACE_DOWN,
			  "IRDP: Interface is down %s", ifp->name);
	}

	/* Shall we cancel if_start if if_add_group fails? */

	if (multicast) {
		if_add_group(ifp);

		if (!(ifp->flags & (IFF_MULTICAST | IFF_ALLMULTI))) {
			flog_warn(EC_ZEBRA_IRDP_IFACE_MCAST_DISABLED,
				  "IRDP: Interface not multicast enabled %s",
				  ifp->name);
		}
	}

	if (set_defaults)
		if_set_defaults(irdp);

	irdp->irdp_sent = 0;

	/* The spec suggests this for randomness */

	seed = 0;
	frr_each (if_connected, ifp->connected, ifc) {
		if (ifc->address->family == AF_INET) {
			seed = ifc->address->u.prefix4.s_addr;
			break;
		}
	}

	srandom(seed);
	timer = (frr_weak_random() % IRDP_DEFAULT_INTERVAL) + 1;

	irdp->AdvPrefList = list_new();
	irdp->AdvPrefList->del = (void (*)(void *))Adv_free; /* Destructor */


	/* And this for startup. Speed limit from 1991 :-). But it's OK*/

	if (irdp->irdp_sent < MAX_INITIAL_ADVERTISEMENTS
	    && timer > MAX_INITIAL_ADVERT_INTERVAL)
		timer = MAX_INITIAL_ADVERT_INTERVAL;


	if (irdp->flags & IF_DEBUG_MISC)
		zlog_debug("IRDP: Init timer for %s set to %u", ifp->name,
			   timer);

	irdp->t_advertise = NULL;
	event_add_timer(zrouter.master, irdp_send_thread, ifp, timer,
			&irdp->t_advertise);
}

static void irdp_if_stop(struct interface *ifp)
{
	struct zebra_if *zi = ifp->info;
	struct irdp_interface *irdp = zi->irdp;

	if (irdp == NULL) {
		zlog_debug("Interface %s structure is NULL", ifp->name);
		return;
	}

	if (!(irdp->flags & IF_ACTIVE)) {
		zlog_debug("Interface is not active %s", ifp->name);
		return;
	}

	if (!(irdp->flags & IF_BROADCAST))
		if_drop_group(ifp);

	irdp_advert_off(ifp);

	list_delete(&irdp->AdvPrefList);

	irdp->flags = 0;
}


static void irdp_if_shutdown(struct interface *ifp)
{
	struct zebra_if *zi = ifp->info;
	struct irdp_interface *irdp = zi->irdp;

	if (!irdp)
		return;

	if (irdp->flags & IF_SHUTDOWN) {
		zlog_debug("IRDP: Interface is already shutdown %s", ifp->name);
		return;
	}

	irdp->flags |= IF_SHUTDOWN;
	irdp->flags &= ~IF_ACTIVE;

	if (!(irdp->flags & IF_BROADCAST))
		if_drop_group(ifp);

	/* Tell the hosts we are out of service */
	irdp_advert_off(ifp);
}

static void irdp_if_no_shutdown(struct interface *ifp)
{
	struct irdp_interface *irdp = irdp_if_get(ifp);

	if (!irdp)
		return;

	if (!(irdp->flags & IF_SHUTDOWN)) {
		zlog_debug("IRDP: Interface is not shutdown %s", ifp->name);
		return;
	}

	irdp->flags &= ~IF_SHUTDOWN;

	irdp_if_start(ifp, irdp->flags & IF_BROADCAST ? false : true, false);
}


/* Write configuration to user */

int irdp_config_write(struct vty *vty, struct interface *ifp)
{
	struct zebra_if *zi = ifp->info;
	struct irdp_interface *irdp = zi->irdp;
	struct Adv *adv;
	struct listnode *node;
	char b1[INET_ADDRSTRLEN];

	if (!irdp)
		return 0;

	if (irdp->flags & IF_ACTIVE || irdp->flags & IF_SHUTDOWN) {

		if (irdp->flags & IF_SHUTDOWN)
			vty_out(vty, " ip irdp shutdown \n");

		if (irdp->flags & IF_BROADCAST)
			vty_out(vty, " ip irdp broadcast\n");
		else
			vty_out(vty, " ip irdp multicast\n");

		vty_out(vty, " ip irdp preference %ld\n", irdp->Preference);

		for (ALL_LIST_ELEMENTS_RO(irdp->AdvPrefList, node, adv))
			vty_out(vty, " ip irdp address %s preference %d\n",
				inet_2a(adv->ip.s_addr, b1, sizeof(b1)),
				adv->pref);

		vty_out(vty, " ip irdp holdtime %d\n", irdp->Lifetime);

		vty_out(vty, " ip irdp minadvertinterval %ld\n",
			irdp->MinAdvertInterval);

		vty_out(vty, " ip irdp maxadvertinterval %ld\n",
			irdp->MaxAdvertInterval);
	}
	return 0;
}


DEFUN (ip_irdp_multicast,
       ip_irdp_multicast_cmd,
       "ip irdp multicast",
       IP_STR
       "ICMP Router discovery on this interface\n"
       "Use multicast mode\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);
	irdp_if_get(ifp);

	irdp_if_start(ifp, true, true);
	return CMD_SUCCESS;
}

DEFUN (ip_irdp_broadcast,
       ip_irdp_broadcast_cmd,
       "ip irdp broadcast",
       IP_STR
       "ICMP Router discovery on this interface\n"
       "Use broadcast mode\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);
	irdp_if_get(ifp);

	irdp_if_start(ifp, false, true);
	return CMD_SUCCESS;
}

DEFUN (no_ip_irdp,
       no_ip_irdp_cmd,
       "no ip irdp",
       NO_STR
       IP_STR
       "Disable ICMP Router discovery on this interface\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);

	irdp_if_stop(ifp);
	return CMD_SUCCESS;
}

DEFUN (ip_irdp_shutdown,
       ip_irdp_shutdown_cmd,
       "ip irdp shutdown",
       IP_STR
       "ICMP Router discovery on this interface\n"
       "ICMP Router discovery shutdown on this interface\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);

	irdp_if_shutdown(ifp);
	return CMD_SUCCESS;
}

DEFUN (no_ip_irdp_shutdown,
       no_ip_irdp_shutdown_cmd,
       "no ip irdp shutdown",
       NO_STR
       IP_STR
       "ICMP Router discovery on this interface\n"
       "ICMP Router discovery no shutdown on this interface\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);

	irdp_if_no_shutdown(ifp);
	return CMD_SUCCESS;
}

DEFUN (ip_irdp_holdtime,
       ip_irdp_holdtime_cmd,
       "ip irdp holdtime (0-9000)",
       IP_STR
       "ICMP Router discovery on this interface\n"
       "Set holdtime value\n"
       "Holdtime value in seconds. Default is 1800 seconds\n")
{
	int idx_number = 3;
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	irdp->Lifetime = atoi(argv[idx_number]->arg);
	return CMD_SUCCESS;
}

DEFUN (ip_irdp_minadvertinterval,
       ip_irdp_minadvertinterval_cmd,
       "ip irdp minadvertinterval (3-1800)",
       IP_STR
       "ICMP Router discovery on this interface\n"
       "Set minimum time between advertisement\n"
       "Minimum advertisement interval in seconds\n")
{
	int idx_number = 3;
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	if ((unsigned)atoi(argv[idx_number]->arg) <= irdp->MaxAdvertInterval) {
		irdp->MinAdvertInterval = atoi(argv[idx_number]->arg);
		return CMD_SUCCESS;
	} else {
		vty_out(vty,
			"%% MinAdvertInterval must be less than or equal to MaxAdvertInterval\n");
		return CMD_WARNING_CONFIG_FAILED;
	}
}

DEFUN (ip_irdp_maxadvertinterval,
       ip_irdp_maxadvertinterval_cmd,
       "ip irdp maxadvertinterval (4-1800)",
       IP_STR
       "ICMP Router discovery on this interface\n"
       "Set maximum time between advertisement\n"
       "Maximum advertisement interval in seconds\n")
{
	int idx_number = 3;
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	if (irdp->MinAdvertInterval <= (unsigned)atoi(argv[idx_number]->arg)) {
		irdp->MaxAdvertInterval = atoi(argv[idx_number]->arg);
		return CMD_SUCCESS;
	} else {
		vty_out(vty,
			"%% MaxAdvertInterval must be greater than or equal to MinAdvertInterval\n");
		return CMD_WARNING_CONFIG_FAILED;
	}
}

/* DEFUN needs to be fixed for negative ranages...
 * "ip irdp preference <-2147483648-2147483647>",
 * Be positive for now. :-)
 */

DEFUN (ip_irdp_preference,
       ip_irdp_preference_cmd,
       "ip irdp preference (0-2147483647)",
       IP_STR
       "ICMP Router discovery on this interface\n"
       "Set default preference level for this interface\n"
       "Preference level\n")
{
	int idx_number = 3;
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	irdp->Preference = atoi(argv[idx_number]->arg);
	return CMD_SUCCESS;
}

DEFUN (ip_irdp_address_preference,
       ip_irdp_address_preference_cmd,
       "ip irdp address A.B.C.D preference (0-2147483647)",
       IP_STR
       "Alter ICMP Router discovery preference on this interface\n"
       "Set IRDP address for advertise\n"
       "IPv4 address\n"
       "Specify IRDP non-default preference to advertise\n"
       "Preference level\n")
{
	int idx_ipv4 = 3;
	int idx_number = 5;
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);
	struct listnode *node;
	struct in_addr ip;
	int pref;
	int ret;
	struct Adv *adv;

	IRDP_CONFIGED;

	ret = inet_aton(argv[idx_ipv4]->arg, &ip);
	if (!ret)
		return CMD_WARNING_CONFIG_FAILED;

	pref = atoi(argv[idx_number]->arg);

	for (ALL_LIST_ELEMENTS_RO(irdp->AdvPrefList, node, adv))
		if (adv->ip.s_addr == ip.s_addr)
			return CMD_SUCCESS;

	adv = Adv_new();
	adv->ip = ip;
	adv->pref = pref;
	listnode_add(irdp->AdvPrefList, adv);

	return CMD_SUCCESS;
}

DEFUN (no_ip_irdp_address_preference,
       no_ip_irdp_address_preference_cmd,
       "no ip irdp address A.B.C.D preference (0-2147483647)",
       NO_STR
       IP_STR
       "Alter ICMP Router discovery preference on this interface\n"
       "Select IRDP address\n"
       "IPv4 address\n"
       "Reset ICMP Router discovery preference on this interface\n"
       "Old preference level\n")
{
	int idx_ipv4 = 4;
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);
	struct listnode *node, *nnode;
	struct in_addr ip;
	int ret;
	struct Adv *adv;

	IRDP_CONFIGED;

	ret = inet_aton(argv[idx_ipv4]->arg, &ip);
	if (!ret)
		return CMD_WARNING_CONFIG_FAILED;

	for (ALL_LIST_ELEMENTS(irdp->AdvPrefList, node, nnode, adv)) {
		if (adv->ip.s_addr == ip.s_addr) {
			listnode_delete(irdp->AdvPrefList, adv);
			break;
		}
	}

	return CMD_SUCCESS;
}

DEFUN (ip_irdp_debug_messages,
       ip_irdp_debug_messages_cmd,
       "ip irdp debug messages",
       IP_STR
       "ICMP Router discovery debug Averts. and Solicits (short)\n"
       "IRDP debugging options\n"
       "Enable debugging for IRDP messages\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	irdp->flags |= IF_DEBUG_MESSAGES;

	return CMD_SUCCESS;
}

DEFUN (ip_irdp_debug_misc,
       ip_irdp_debug_misc_cmd,
       "ip irdp debug misc",
       IP_STR
       "ICMP Router discovery debug Averts. and Solicits (short)\n"
       "IRDP debugging options\n"
       "Enable debugging for miscellaneous IRDP events\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	irdp->flags |= IF_DEBUG_MISC;

	return CMD_SUCCESS;
}

DEFUN (ip_irdp_debug_packet,
       ip_irdp_debug_packet_cmd,
       "ip irdp debug packet",
       IP_STR
       "ICMP Router discovery debug Averts. and Solicits (short)\n"
       "IRDP debugging options\n"
       "Enable debugging for IRDP packets\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	irdp->flags |= IF_DEBUG_PACKET;

	return CMD_SUCCESS;
}


DEFUN (ip_irdp_debug_disable,
       ip_irdp_debug_disable_cmd,
       "ip irdp debug disable",
       IP_STR
       "ICMP Router discovery debug Averts. and Solicits (short)\n"
       "IRDP debugging options\n"
       "Disable debugging for all IRDP events\n")
{
	VTY_DECLVAR_CONTEXT(interface, ifp);
	struct irdp_interface *irdp = irdp_if_get(ifp);

	IRDP_CONFIGED;

	irdp->flags &= ~IF_DEBUG_PACKET;
	irdp->flags &= ~IF_DEBUG_MESSAGES;
	irdp->flags &= ~IF_DEBUG_MISC;

	return CMD_SUCCESS;
}

void irdp_if_init(void)
{
	hook_register(if_del, irdp_if_delete);

	install_element(INTERFACE_NODE, &ip_irdp_broadcast_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_multicast_cmd);
	install_element(INTERFACE_NODE, &no_ip_irdp_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_shutdown_cmd);
	install_element(INTERFACE_NODE, &no_ip_irdp_shutdown_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_holdtime_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_maxadvertinterval_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_minadvertinterval_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_preference_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_address_preference_cmd);
	install_element(INTERFACE_NODE, &no_ip_irdp_address_preference_cmd);

	install_element(INTERFACE_NODE, &ip_irdp_debug_messages_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_debug_misc_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_debug_packet_cmd);
	install_element(INTERFACE_NODE, &ip_irdp_debug_disable_cmd);
}