path: root/isisd/isis_dlpi.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * IS-IS Rout(e)ing protocol - isis_dlpi.c
 *
 * Copyright (C) 2001,2002    Sampo Saaristo
 *                            Tampere University of Technology
 *                            Institute of Communications Engineering
 */

#include <zebra.h>
#if ISIS_METHOD == ISIS_METHOD_DLPI
#include <net/if.h>
#include <netinet/if_ether.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <stropts.h>
#include <poll.h>
#include <sys/dlpi.h>
#include <sys/pfmod.h>

#include "log.h"
#include "network.h"
#include "stream.h"
#include "if.h"
#include "lib_errors.h"

#include "isisd/isis_constants.h"
#include "isisd/isis_common.h"
#include "isisd/isis_circuit.h"
#include "isisd/isis_flags.h"
#include "isisd/isisd.h"
#include "isisd/isis_network.h"

#include "privs.h"

static t_uscalar_t dlpi_ctl[1024]; /* DLPI control messages */

/*
 * Table 9 - Architectural constants for use with ISO 8802 subnetworks
 * ISO 10589 - 8.4.8
 */

static const uint8_t ALL_L1_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x14};
static const uint8_t ALL_L2_ISS[6] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x15};
static const uint8_t ALL_ISS[6] = {0x09, 0x00, 0x2B, 0x00, 0x00, 0x05};
static uint8_t sock_buff[16384];

static unsigned short pf_filter[] = {
	ENF_PUSHWORD + 0,       /* Get the SSAP/DSAP values */
	ENF_PUSHLIT | ENF_CAND, /* Check them */
	ISO_SAP | (ISO_SAP << 8),
	ENF_PUSHWORD + 1,      /* Get the control value */
	ENF_PUSHLIT | ENF_AND, /* Isolate it */
#ifdef _BIG_ENDIAN
	0xFF00,
#else
	0x00FF,
#endif
	ENF_PUSHLIT | ENF_CAND, /* Test for expected value */
#ifdef _BIG_ENDIAN
	0x0300
#else
	0x0003
#endif
};

/*
 * We would like to use something like libdlpi here, but that's not present on
 * all versions of Solaris or on any non-Solaris system, so it's nowhere near
 * as portable as we'd like.  Thus, we use the standards-conformant DLPI
 * interfaces plus the (optional; not needed) Solaris packet filter module.
 */

static int dlpisend(int fd, const void *cbuf, size_t cbuflen, const void *dbuf,
		    size_t dbuflen, int flags)
{
	const struct strbuf *ctlptr = NULL;
	const struct strbuf *dataptr = NULL;
	struct strbuf ctlbuf, databuf;
	int rv;

	if (cbuf != NULL) {
		memset(&ctlbuf, 0, sizeof(ctlbuf));
		ctlbuf.len = cbuflen;
		ctlbuf.buf = (void *)cbuf;
		ctlptr = &ctlbuf;
	}

	if (dbuf != NULL) {
		memset(&databuf, 0, sizeof(databuf));
		databuf.len = dbuflen;
		databuf.buf = (void *)dbuf;
		dataptr = &databuf;
	}

	/* We assume this doesn't happen often and isn't operationally
	 * significant */
	rv = putmsg(fd, ctlptr, dataptr, flags);
	if (rv == -1 && dbuf == NULL) {
		/*
		 * For actual PDU transmission - recognizable buf dbuf != NULL,
		 * the error is passed upwards and should not be printed here.
		 */
		zlog_debug("%s: putmsg: %s", __func__, safe_strerror(errno));
	}
	return rv;
}

static ssize_t dlpirctl(int fd)
{
	struct pollfd fds[1];
	struct strbuf ctlbuf, databuf;
	int flags, retv;

	do {
		/* Poll is used here in case the device doesn't speak DLPI
		 * correctly */
		memset(fds, 0, sizeof(fds));
		fds[0].fd = fd;
		fds[0].events = POLLIN | POLLPRI;
		if (poll(fds, 1, 1000) <= 0)
			return -1;

		memset(&ctlbuf, 0, sizeof(ctlbuf));
		memset(&databuf, 0, sizeof(databuf));
		ctlbuf.maxlen = sizeof(dlpi_ctl);
		ctlbuf.buf = (void *)dlpi_ctl;
		databuf.maxlen = sizeof(sock_buff);
		databuf.buf = (void *)sock_buff;
		flags = 0;
		retv = getmsg(fd, &ctlbuf, &databuf, &flags);

		if (retv < 0)
			return -1;
	} while (ctlbuf.len == 0);

	if (!(retv & MORECTL)) {
		while (retv & MOREDATA) {
			flags = 0;
			retv = getmsg(fd, NULL, &databuf, &flags);
		}
		return ctlbuf.len;
	}

	while (retv & MORECTL) {
		flags = 0;
		retv = getmsg(fd, &ctlbuf, &databuf, &flags);
	}
	return -1;
}

static int dlpiok(int fd, t_uscalar_t oprim)
{
	int retv;
	dl_ok_ack_t *doa = (dl_ok_ack_t *)dlpi_ctl;

	retv = dlpirctl(fd);
	if (retv < (ssize_t)DL_OK_ACK_SIZE || doa->dl_primitive != DL_OK_ACK
	    || doa->dl_correct_primitive != oprim) {
		return -1;
	} else {
		return 0;
	}
}

static int dlpiinfo(int fd)
{
	dl_info_req_t dir;
	ssize_t retv;

	memset(&dir, 0, sizeof(dir));
	dir.dl_primitive = DL_INFO_REQ;
	/* Info_req uses M_PCPROTO. */
	dlpisend(fd, &dir, sizeof(dir), NULL, 0, RS_HIPRI);
	retv = dlpirctl(fd);
	if (retv < (ssize_t)DL_INFO_ACK_SIZE || dlpi_ctl[0] != DL_INFO_ACK)
		return -1;
	else
		return retv;
}

static int dlpiopen(const char *devpath, ssize_t *acklen)
{
	int fd, flags;

	fd = open(devpath, O_RDWR | O_NONBLOCK | O_NOCTTY);
	if (fd == -1)
		return -1;

	/* All that we want is for the open itself to be non-blocking, not I/O.
	 */
	flags = fcntl(fd, F_GETFL, 0);
	if (flags != -1)
		fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);

	/* After opening, ask for information */
	if ((*acklen = dlpiinfo(fd)) == -1) {
		close(fd);
		return -1;
	}

	return fd;
}

static int dlpiattach(int fd, int unit)
{
	dl_attach_req_t dar;

	memset(&dar, 0, sizeof(dar));
	dar.dl_primitive = DL_ATTACH_REQ;
	dar.dl_ppa = unit;
	dlpisend(fd, &dar, sizeof(dar), NULL, 0, 0);
	return dlpiok(fd, dar.dl_primitive);
}

static int dlpibind(int fd)
{
	dl_bind_req_t dbr;
	int retv;
	dl_bind_ack_t *dba = (dl_bind_ack_t *)dlpi_ctl;

	memset(&dbr, 0, sizeof(dbr));
	dbr.dl_primitive = DL_BIND_REQ;
	dbr.dl_service_mode = DL_CLDLS;
	dlpisend(fd, &dbr, sizeof(dbr), NULL, 0, 0);

	retv = dlpirctl(fd);
	if (retv < (ssize_t)DL_BIND_ACK_SIZE
	    || dba->dl_primitive != DL_BIND_ACK)
		return -1;
	else
		return 0;
}

static int dlpimcast(int fd, const uint8_t *mcaddr)
{
	struct {
		dl_enabmulti_req_t der;
		uint8_t addr[ETHERADDRL];
	} dler;

	memset(&dler, 0, sizeof(dler));
	dler.der.dl_primitive = DL_ENABMULTI_REQ;
	dler.der.dl_addr_length = sizeof(dler.addr);
	dler.der.dl_addr_offset = dler.addr - (uint8_t *)&dler;
	memcpy(dler.addr, mcaddr, sizeof(dler.addr));
	dlpisend(fd, &dler, sizeof(dler), NULL, 0, 0);
	return dlpiok(fd, dler.der.dl_primitive);
}

static int dlpiaddr(int fd, uint8_t *addr)
{
	dl_phys_addr_req_t dpar;
	dl_phys_addr_ack_t *dpaa = (dl_phys_addr_ack_t *)dlpi_ctl;
	int retv;

	memset(&dpar, 0, sizeof(dpar));
	dpar.dl_primitive = DL_PHYS_ADDR_REQ;
	dpar.dl_addr_type = DL_CURR_PHYS_ADDR;
	dlpisend(fd, &dpar, sizeof(dpar), NULL, 0, 0);

	retv = dlpirctl(fd);
	if (retv < (ssize_t)DL_PHYS_ADDR_ACK_SIZE
	    || dpaa->dl_primitive != DL_PHYS_ADDR_ACK)
		return -1;

	if (dpaa->dl_addr_offset < DL_PHYS_ADDR_ACK_SIZE
	    || dpaa->dl_addr_length != ETHERADDRL
	    || dpaa->dl_addr_offset + dpaa->dl_addr_length > (size_t)retv)
		return -1;

	bcopy((char *)dpaa + dpaa->dl_addr_offset, addr, ETHERADDRL);
	return 0;
}

static int open_dlpi_dev(struct isis_circuit *circuit)
{
	int fd = -1, unit, retval;
	char devpath[MAXPATHLEN];
	dl_info_ack_t *dia = (dl_info_ack_t *)dlpi_ctl;
	ssize_t acklen;

	/* Only broadcast-type are supported at the moment */
	if (circuit->circ_type != CIRCUIT_T_BROADCAST) {
		zlog_warn("%s: non-broadcast interface %s", __func__,
			  circuit->interface->name);
		return ISIS_WARNING;
	}

	/* Try the vanity node first, if permitted */
	if (getenv("DLPI_DEVONLY") == NULL) {
		(void)snprintf(devpath, sizeof(devpath), "/dev/net/%s",
			       circuit->interface->name);
		fd = dlpiopen(devpath, &acklen);
	}

	/* Now try as an ordinary Style 1 node */
	if (fd == -1) {
		(void)snprintf(devpath, sizeof(devpath), "/dev/%s",
			       circuit->interface->name);
		unit = -1;
		fd = dlpiopen(devpath, &acklen);
	}

	/* If that fails, try again as Style 2 */
	if (fd == -1) {
		char *cp;

		cp = devpath + strlen(devpath);
		while (--cp >= devpath && isdigit(*cp))
			;
		unit = strtol(cp, NULL, 0);
		*cp = '\0';
		fd = dlpiopen(devpath, &acklen);

		/* If that too fails, then the device really doesn't exist */
		if (fd == -1) {
			zlog_warn("%s: unknown interface %s", __func__,
				  circuit->interface->name);
			return ISIS_WARNING;
		}

		/* Double check the DLPI style */
		if (dia->dl_provider_style != DL_STYLE2) {
			zlog_warn("%s: interface %s: %s is not style 2",
				  __func__, circuit->interface->name, devpath);
			close(fd);
			return ISIS_WARNING;
		}

		/* If it succeeds, then we need to attach to the unit specified
		 */
		dlpiattach(fd, unit);

		/* Reget the information, as it may be different per node */
		if ((acklen = dlpiinfo(fd)) == -1) {
			close(fd);
			return ISIS_WARNING;
		}
	} else {
		/* Double check the DLPI style */
		if (dia->dl_provider_style != DL_STYLE1) {
			zlog_warn("%s: interface %s: %s is not style 1",
				  __func__, circuit->interface->name, devpath);
			close(fd);
			return ISIS_WARNING;
		}
	}

	/* Check that the interface we've got is the kind we expect */
	if ((dia->dl_sap_length != 2 && dia->dl_sap_length != -2)
	    || dia->dl_service_mode != DL_CLDLS
	    || dia->dl_addr_length != ETHERADDRL + 2
	    || dia->dl_brdcst_addr_length != ETHERADDRL) {
		zlog_warn("%s: unsupported interface type for %s", __func__,
			  circuit->interface->name);
		close(fd);
		return ISIS_WARNING;
	}
	switch (dia->dl_mac_type) {
	case DL_CSMACD:
	case DL_ETHER:
	case DL_100VG:
	case DL_100VGTPR:
	case DL_ETH_CSMA:
	case DL_100BT:
		break;
	default:
		zlog_warn("%s: unexpected mac type on %s: %lld", __func__,
			  circuit->interface->name,
			  (long long)dia->dl_mac_type);
		close(fd);
		return ISIS_WARNING;
	}

	circuit->sap_length = dia->dl_sap_length;

	/*
	 * The local hardware address is something that should be provided by
	 * way of
	 * sockaddr_dl for the interface, but isn't on Solaris.  We set it here
	 * based
	 * on DLPI's reported address to avoid roto-tilling the world.
	 * (Note that isis_circuit_if_add on Solaris doesn't set the snpa.)
	 *
	 * Unfortunately, GLD is broken and doesn't provide the address after
	 * attach,
	 * so we need to be careful and use DL_PHYS_ADDR_REQ instead.
	 */
	if (dlpiaddr(fd, circuit->u.bc.snpa) == -1) {
		zlog_warn("%s: interface %s: unable to get MAC address",
			  __func__, circuit->interface->name);
		close(fd);
		return ISIS_WARNING;
	}

	/* Now bind to SAP 0.  This gives us 802-type traffic. */
	if (dlpibind(fd) == -1) {
		zlog_warn("%s: cannot bind SAP 0 on %s", __func__,
			  circuit->interface->name);
		close(fd);
		return ISIS_WARNING;
	}

	/*
	 * Join to multicast groups according to
	 * 8.4.2 - Broadcast subnetwork IIH PDUs
	 */
	retval = 0;
	retval |= dlpimcast(fd, ALL_L1_ISS);
	retval |= dlpimcast(fd, ALL_ISS);
	retval |= dlpimcast(fd, ALL_L2_ISS);

	if (retval != 0) {
		zlog_warn("%s: unable to join multicast on %s", __func__,
			  circuit->interface->name);
		close(fd);
		return ISIS_WARNING;
	}

	/* Push on the packet filter to avoid stray 802 packets */
	if (ioctl(fd, I_PUSH, "pfmod") == 0) {
		struct packetfilt pfil;
		struct strioctl sioc;

		pfil.Pf_Priority = 0;
		pfil.Pf_FilterLen = array_size(pf_filter);
		memcpy(pfil.Pf_Filter, pf_filter, sizeof(pf_filter));
		/* pfmod does not support transparent ioctls */
		sioc.ic_cmd = PFIOCSETF;
		sioc.ic_timout = 5;
		sioc.ic_len = sizeof(struct packetfilt);
		sioc.ic_dp = (char *)&pfil;
		if (ioctl(fd, I_STR, &sioc) == -1)
			zlog_warn("%s: could not perform PF_IOCSETF on %s",
				  __func__, circuit->interface->name);
	}

	circuit->fd = fd;

	return ISIS_OK;
}

/*
 * Create the socket and set the tx/rx funcs
 */
int isis_sock_init(struct isis_circuit *circuit)
{
	int retval = ISIS_OK;

	frr_with_privs(&isisd_privs) {

		retval = open_dlpi_dev(circuit);

		if (retval != ISIS_OK) {
			zlog_warn("%s: could not initialize the socket",
				  __func__);
			break;
		}

		if (circuit->circ_type == CIRCUIT_T_BROADCAST) {
			circuit->tx = isis_send_pdu_bcast;
			circuit->rx = isis_recv_pdu_bcast;
		} else {
			zlog_warn("%s: unknown circuit type", __func__);
			retval = ISIS_WARNING;
			break;
		}
	}

	return retval;
}

int isis_recv_pdu_bcast(struct isis_circuit *circuit, uint8_t *ssnpa)
{
	struct pollfd fds[1];
	struct strbuf ctlbuf, databuf;
	int flags, retv;
	dl_unitdata_ind_t *dui = (dl_unitdata_ind_t *)dlpi_ctl;

	memset(fds, 0, sizeof(fds));
	fds[0].fd = circuit->fd;
	fds[0].events = POLLIN | POLLPRI;
	if (poll(fds, 1, 0) <= 0)
		return ISIS_WARNING;

	memset(&ctlbuf, 0, sizeof(ctlbuf));
	memset(&databuf, 0, sizeof(databuf));
	ctlbuf.maxlen = sizeof(dlpi_ctl);
	ctlbuf.buf = (void *)dlpi_ctl;
	databuf.maxlen = sizeof(sock_buff);
	databuf.buf = (void *)sock_buff;
	flags = 0;
	retv = getmsg(circuit->fd, &ctlbuf, &databuf, &flags);

	if (retv < 0) {
		zlog_warn("%s: getmsg failed: %s", __func__,
			  safe_strerror(errno));
		return ISIS_WARNING;
	}

	if (retv & (MORECTL | MOREDATA)) {
		while (retv & (MORECTL | MOREDATA)) {
			flags = 0;
			retv = getmsg(circuit->fd, &ctlbuf, &databuf, &flags);
		}
		return ISIS_WARNING;
	}

	if (ctlbuf.len < (ssize_t)DL_UNITDATA_IND_SIZE
	    || dui->dl_primitive != DL_UNITDATA_IND)
		return ISIS_WARNING;

	if (dui->dl_src_addr_length != ETHERADDRL + 2
	    || dui->dl_src_addr_offset < DL_UNITDATA_IND_SIZE
	    || dui->dl_src_addr_offset + dui->dl_src_addr_length
		       > (size_t)ctlbuf.len)
		return ISIS_WARNING;

	memcpy(ssnpa,
	       (char *)dui + dui->dl_src_addr_offset
		       + (circuit->sap_length > 0 ? circuit->sap_length : 0),
	       ETHERADDRL);

	if (databuf.len < LLC_LEN || sock_buff[0] != ISO_SAP
	    || sock_buff[1] != ISO_SAP || sock_buff[2] != 3)
		return ISIS_WARNING;

	stream_write(circuit->rcv_stream, sock_buff + LLC_LEN,
		     databuf.len - LLC_LEN);
	stream_set_getp(circuit->rcv_stream, 0);

	return ISIS_OK;
}

int isis_send_pdu_bcast(struct isis_circuit *circuit, int level)
{
	dl_unitdata_req_t *dur = (dl_unitdata_req_t *)dlpi_ctl;
	char *dstaddr;
	unsigned short *dstsap;
	int buflen;
	int rv;

	buflen = stream_get_endp(circuit->snd_stream) + LLC_LEN;
	if ((size_t)buflen > sizeof(sock_buff)) {
		zlog_warn(
			"%s: sock_buff size %zu is less than output pdu size %d on circuit %s",
			__func__, sizeof(sock_buff), buflen,
			circuit->interface->name);
		return ISIS_WARNING;
	}

	stream_set_getp(circuit->snd_stream, 0);

	memset(dur, 0, sizeof(*dur));
	dur->dl_primitive = DL_UNITDATA_REQ;
	dur->dl_dest_addr_length = ETHERADDRL + 2;
	dur->dl_dest_addr_offset = sizeof(*dur);

	dstaddr = (char *)(dur + 1);
	if (circuit->sap_length < 0) {
		dstsap = (unsigned short *)(dstaddr + ETHERADDRL);
	} else {
		dstsap = (unsigned short *)dstaddr;
		dstaddr += circuit->sap_length;
	}
	if (level == 1)
		memcpy(dstaddr, ALL_L1_ISS, ETHERADDRL);
	else
		memcpy(dstaddr, ALL_L2_ISS, ETHERADDRL);
	/* Note: DLPI SAP values are in host byte order */
	*dstsap = buflen;

	sock_buff[0] = ISO_SAP;
	sock_buff[1] = ISO_SAP;
	sock_buff[2] = 0x03;
	memcpy(sock_buff + LLC_LEN, circuit->snd_stream->data,
	       stream_get_endp(circuit->snd_stream));
	rv = dlpisend(circuit->fd, dur, sizeof(*dur) + dur->dl_dest_addr_length,
		      sock_buff, buflen, 0);
	if (rv < 0) {
		zlog_warn("IS-IS dlpi: could not transmit packet on %s: %s",
			  circuit->interface->name, safe_strerror(errno));
		if (ERRNO_IO_RETRY(errno))
			return ISIS_WARNING;
		return ISIS_ERROR;
	}

	return ISIS_OK;
}

#endif /* ISIS_METHOD == ISIS_METHOD_DLPI */