pim_tlv.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PIM for Quagga
 * Copyright (C) 2008  Everton da Silva Marques
 */

#include <zebra.h>

#include "log.h"
#include "prefix.h"
#include "if.h"

#include "pimd.h"
#include "pim_instance.h"
#include "pim_int.h"
#include "pim_tlv.h"
#include "pim_str.h"
#include "pim_msg.h"
#include "pim_iface.h"
#include "pim_addr.h"

uint8_t *pim_tlv_append_uint16(uint8_t *buf, const uint8_t *buf_pastend,
			       uint16_t option_type, uint16_t option_value)
{
	uint16_t option_len = 2;

	if ((buf + PIM_TLV_OPTION_SIZE(option_len)) > buf_pastend)
		return NULL;

	*(uint16_t *)buf = htons(option_type);
	buf += 2;
	*(uint16_t *)buf = htons(option_len);
	buf += 2;
	*(uint16_t *)buf = htons(option_value);
	buf += option_len;

	return buf;
}

uint8_t *pim_tlv_append_2uint16(uint8_t *buf, const uint8_t *buf_pastend,
				uint16_t option_type, uint16_t option_value1,
				uint16_t option_value2)
{
	uint16_t option_len = 4;

	if ((buf + PIM_TLV_OPTION_SIZE(option_len)) > buf_pastend)
		return NULL;

	*(uint16_t *)buf = htons(option_type);
	buf += 2;
	*(uint16_t *)buf = htons(option_len);
	buf += 2;
	*(uint16_t *)buf = htons(option_value1);
	buf += 2;
	*(uint16_t *)buf = htons(option_value2);
	buf += 2;

	return buf;
}

uint8_t *pim_tlv_append_uint32(uint8_t *buf, const uint8_t *buf_pastend,
			       uint16_t option_type, uint32_t option_value)
{
	uint16_t option_len = 4;

	if ((buf + PIM_TLV_OPTION_SIZE(option_len)) > buf_pastend)
		return NULL;

	*(uint16_t *)buf = htons(option_type);
	buf += 2;
	*(uint16_t *)buf = htons(option_len);
	buf += 2;
	pim_write_uint32(buf, option_value);
	buf += option_len;

	return buf;
}

#define ucast_ipv4_encoding_len (2 + sizeof(struct in_addr))
#define ucast_ipv6_encoding_len (2 + sizeof(struct in6_addr))

/*
 * An Encoded-Unicast address takes the following format:
 *
 *   0                   1                   2                   3
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |  Addr Family  | Encoding Type |     Unicast Address
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...
 *
 *  Addr Family
 *       The PIM address family of the 'Unicast Address' field of this
 *       address.
 *
 *       Values 0-127 are as assigned by the IANA for Internet Address   *
 * Families in [7].  Values 128-250 are reserved to be assigned by
 *       the IANA for PIM-specific Address Families.  Values 251 though
 *       255 are designated for private use.  As there is no assignment
 *       authority for this space, collisions should be expected.
 *
 *  Encoding Type
 *       The type of encoding used within a specific Address Family.  The
 *       value '0' is reserved for this field and represents the native
 *       encoding of the Address Family.
 *
 *  Unicast Address
 *       The unicast address as represented by the given Address Family
 *       and Encoding Type.
 */
int pim_encode_addr_ucast(uint8_t *buf, pim_addr addr)
{
	uint8_t *start = buf;

	*buf++ = PIM_MSG_ADDRESS_FAMILY;
	*buf++ = 0;
	memcpy(buf, &addr, sizeof(addr));
	buf += sizeof(addr);

	return buf - start;
}

int pim_encode_addr_ucast_prefix(uint8_t *buf, struct prefix *p)
{
	switch (p->family) {
	case AF_INET:
		*buf = PIM_MSG_ADDRESS_FAMILY_IPV4; /* notice: AF_INET !=
						       PIM_MSG_ADDRESS_FAMILY_IPV4
						       */
		++buf;
		*buf = 0; /* ucast IPv4 native encoding type (RFC
					4601: 4.9.1) */
		++buf;
		memcpy(buf, &p->u.prefix4, sizeof(struct in_addr));
		return ucast_ipv4_encoding_len;
	case AF_INET6:
		*buf = PIM_MSG_ADDRESS_FAMILY_IPV6;
		++buf;
		*buf = 0;
		++buf;
		memcpy(buf, &p->u.prefix6, sizeof(struct in6_addr));
		return ucast_ipv6_encoding_len;
	default:
		return 0;
	}
}

#define group_ipv4_encoding_len (4 + sizeof(struct in_addr))

/*
 * Encoded-Group addresses take the following format:
 *
 *   0                   1                   2                   3
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |  Addr Family  | Encoding Type |B| Reserved  |Z|  Mask Len     |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                Group multicast Address
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...
 *
 *  Addr Family
 *       Described above.
 *
 *  Encoding Type
 *       Described above.
 *
 *  [B]idirectional PIM
 *       Indicates the group range should use Bidirectional PIM [13].
 *       For PIM-SM defined in this specification, this bit MUST be zero.
 *
 *  Reserved
 *       Transmitted as zero.  Ignored upon receipt.
 *
 *  Admin Scope [Z]one
 *       indicates the group range is an admin scope zone.  This is used
 *       in the Bootstrap Router Mechanism [11] only.  For all other
 *       purposes, this bit is set to zero and ignored on receipt.
 *
 *  Mask Len
 *       The Mask length field is 8 bits.  The value is the number of
 *       contiguous one bits that are left justified and used as a mask;
 *       when combined with the group address, it describes a range of
 *       groups.  It is less than or equal to the address length in bits
 *       for the given Address Family and Encoding Type.  If the message
 *       is sent for a single group, then the Mask length must equal the
 *       address length in bits for the given Address Family and Encoding
 *       Type (e.g., 32 for IPv4 native encoding, 128 for IPv6 native
 *       encoding).
 *
 *  Group multicast Address
 *       Contains the group address.
 */
int pim_encode_addr_group(uint8_t *buf, afi_t afi, int bidir, int scope,
			  pim_addr group)
{
	uint8_t *start = buf;
	uint8_t flags = 0;

	flags |= bidir << 8;
	flags |= scope;

	*buf++ = PIM_MSG_ADDRESS_FAMILY;
	*buf++ = 0;
	*buf++ = flags;
	*buf++ = sizeof(group) * 8;
	memcpy(buf, &group, sizeof(group));
	buf += sizeof(group);

	return buf - start;
}

uint8_t *pim_tlv_append_addrlist_ucast(uint8_t *buf, const uint8_t *buf_pastend,
				       struct interface *ifp, int family)
{
	uint16_t option_len = 0;
	uint8_t *curr;
	size_t uel;
	struct connected *ifc;
	struct pim_interface *pim_ifp = ifp->info;
	pim_addr addr;

	ifc = if_connected_first(ifp->connected);

	/* Empty address list ? */
	if (!ifc) {
		return buf;
	}

	if (family == AF_INET)
		uel = ucast_ipv4_encoding_len;
	else
		uel = ucast_ipv6_encoding_len;

	/* Scan secondary address list */
	curr = buf + 4; /* skip T and L */
	for (; ifc; ifc = if_connected_next(ifp->connected, ifc)) {
		struct prefix *p = ifc->address;
		int l_encode;

		addr = pim_addr_from_prefix(p);
		if (!pim_addr_cmp(pim_ifp->primary_address, addr))
			/* don't add the primary address
			 * into the secondary address list */
			continue;

		if ((curr + uel) > buf_pastend)
			return 0;

		if (p->family != family)
			continue;

		l_encode = pim_encode_addr_ucast_prefix(curr, p);
		curr += l_encode;
		option_len += l_encode;
	}

	if (PIM_DEBUG_PIM_TRACE_DETAIL) {
		zlog_debug(
			"%s: number of encoded secondary unicast IPv4 addresses: %zu",
			__func__, option_len / uel);
	}

	if (option_len < 1) {
		/* Empty secondary unicast IPv4 address list */
		return buf;
	}

	/*
	 * Write T and L
	 */
	*(uint16_t *)buf = htons(PIM_MSG_OPTION_TYPE_ADDRESS_LIST);
	*(uint16_t *)(buf + 2) = htons(option_len);

	return curr;
}

static int check_tlv_length(const char *label, const char *tlv_name,
			    const char *ifname, pim_addr src_addr,
			    int correct_len, int option_len)
{
	if (option_len != correct_len) {
		zlog_warn(
			"%s: PIM hello %s TLV with incorrect value size=%d correct=%d from %pPAs on interface %s",
			label, tlv_name, option_len, correct_len, &src_addr,
			ifname);
		return -1;
	}

	return 0;
}

static void check_tlv_redefinition_uint16(const char *label,
					  const char *tlv_name,
					  const char *ifname, pim_addr src_addr,
					  pim_hello_options options,
					  pim_hello_options opt_mask,
					  uint16_t new, uint16_t old)
{
	if (PIM_OPTION_IS_SET(options, opt_mask))
		zlog_warn(
			"%s: PIM hello TLV redefined %s=%u old=%u from %pPAs on interface %s",
			label, tlv_name, new, old, &src_addr, ifname);
}

static void check_tlv_redefinition_uint32(const char *label,
					  const char *tlv_name,
					  const char *ifname, pim_addr src_addr,
					  pim_hello_options options,
					  pim_hello_options opt_mask,
					  uint32_t new, uint32_t old)
{
	if (PIM_OPTION_IS_SET(options, opt_mask))
		zlog_warn(
			"%s: PIM hello TLV redefined %s=%u old=%u from %pPAs on interface %s",
			label, tlv_name, new, old, &src_addr, ifname);
}

static void check_tlv_redefinition_uint32_hex(
	const char *label, const char *tlv_name, const char *ifname,
	pim_addr src_addr, pim_hello_options options,
	pim_hello_options opt_mask, uint32_t new, uint32_t old)
{
	if (PIM_OPTION_IS_SET(options, opt_mask))
		zlog_warn(
			"%s: PIM hello TLV redefined %s=%08x old=%08x from %pPAs on interface %s",
			label, tlv_name, new, old, &src_addr, ifname);
}

int pim_tlv_parse_holdtime(const char *ifname, pim_addr src_addr,
			   pim_hello_options *hello_options,
			   uint16_t *hello_option_holdtime, uint16_t option_len,
			   const uint8_t *tlv_curr)
{
	const char *label = "holdtime";

	if (check_tlv_length(__func__, label, ifname, src_addr,
			     sizeof(uint16_t), option_len)) {
		return -1;
	}

	check_tlv_redefinition_uint16(__func__, label, ifname, src_addr,
				      *hello_options, PIM_OPTION_MASK_HOLDTIME,
				      PIM_TLV_GET_HOLDTIME(tlv_curr),
				      *hello_option_holdtime);

	PIM_OPTION_SET(*hello_options, PIM_OPTION_MASK_HOLDTIME);

	*hello_option_holdtime = PIM_TLV_GET_HOLDTIME(tlv_curr);

	return 0;
}

int pim_tlv_parse_lan_prune_delay(const char *ifname, pim_addr src_addr,
				  pim_hello_options *hello_options,
				  uint16_t *hello_option_propagation_delay,
				  uint16_t *hello_option_override_interval,
				  uint16_t option_len, const uint8_t *tlv_curr)
{
	if (check_tlv_length(__func__, "lan_prune_delay", ifname, src_addr,
			     sizeof(uint32_t), option_len)) {
		return -1;
	}

	check_tlv_redefinition_uint16(__func__, "propagation_delay", ifname,
				      src_addr, *hello_options,
				      PIM_OPTION_MASK_LAN_PRUNE_DELAY,
				      PIM_TLV_GET_PROPAGATION_DELAY(tlv_curr),
				      *hello_option_propagation_delay);

	PIM_OPTION_SET(*hello_options, PIM_OPTION_MASK_LAN_PRUNE_DELAY);

	*hello_option_propagation_delay =
		PIM_TLV_GET_PROPAGATION_DELAY(tlv_curr);
	if (PIM_TLV_GET_CAN_DISABLE_JOIN_SUPPRESSION(tlv_curr)) {
		PIM_OPTION_SET(*hello_options,
			       PIM_OPTION_MASK_CAN_DISABLE_JOIN_SUPPRESSION);
	} else {
		PIM_OPTION_UNSET(*hello_options,
				 PIM_OPTION_MASK_CAN_DISABLE_JOIN_SUPPRESSION);
	}
	++tlv_curr;
	++tlv_curr;
	*hello_option_override_interval =
		PIM_TLV_GET_OVERRIDE_INTERVAL(tlv_curr);

	return 0;
}

int pim_tlv_parse_dr_priority(const char *ifname, pim_addr src_addr,
			      pim_hello_options *hello_options,
			      uint32_t *hello_option_dr_priority,
			      uint16_t option_len, const uint8_t *tlv_curr)
{
	const char *label = "dr_priority";

	if (check_tlv_length(__func__, label, ifname, src_addr,
			     sizeof(uint32_t), option_len)) {
		return -1;
	}

	check_tlv_redefinition_uint32(
		__func__, label, ifname, src_addr, *hello_options,
		PIM_OPTION_MASK_DR_PRIORITY, PIM_TLV_GET_DR_PRIORITY(tlv_curr),
		*hello_option_dr_priority);

	PIM_OPTION_SET(*hello_options, PIM_OPTION_MASK_DR_PRIORITY);

	*hello_option_dr_priority = PIM_TLV_GET_DR_PRIORITY(tlv_curr);

	return 0;
}

int pim_tlv_parse_generation_id(const char *ifname, pim_addr src_addr,
				pim_hello_options *hello_options,
				uint32_t *hello_option_generation_id,
				uint16_t option_len, const uint8_t *tlv_curr)
{
	const char *label = "generation_id";

	if (check_tlv_length(__func__, label, ifname, src_addr,
			     sizeof(uint32_t), option_len)) {
		return -1;
	}

	check_tlv_redefinition_uint32_hex(__func__, label, ifname, src_addr,
					  *hello_options,
					  PIM_OPTION_MASK_GENERATION_ID,
					  PIM_TLV_GET_GENERATION_ID(tlv_curr),
					  *hello_option_generation_id);

	PIM_OPTION_SET(*hello_options, PIM_OPTION_MASK_GENERATION_ID);

	*hello_option_generation_id = PIM_TLV_GET_GENERATION_ID(tlv_curr);

	return 0;
}

int pim_parse_addr_ucast_prefix(struct prefix *p, const uint8_t *buf,
				int buf_size)
{
	const int ucast_encoding_min_len = 3; /* 1 family + 1 type + 1 addr */
	const uint8_t *addr;
	const uint8_t *pastend;
	int family;
	int type;

	if (buf_size < ucast_encoding_min_len) {
		zlog_warn(
			"%s: unicast address encoding overflow: left=%d needed=%d",
			__func__, buf_size, ucast_encoding_min_len);
		return -1;
	}

	addr = buf;
	pastend = buf + buf_size;

	family = *addr++;
	type = *addr++;

	if (type) {
		zlog_warn("%s: unknown unicast address encoding type=%d",
			  __func__, type);
		return -2;
	}

	switch (family) {
	case PIM_MSG_ADDRESS_FAMILY_IPV4:
		if ((addr + sizeof(struct in_addr)) > pastend) {
			zlog_warn(
				"%s: IPv4 unicast address overflow: left=%td needed=%zu",
				__func__, pastend - addr,
				sizeof(struct in_addr));
			return -3;
		}

		p->family = AF_INET; /* notice: AF_INET !=
					PIM_MSG_ADDRESS_FAMILY_IPV4 */
		memcpy(&p->u.prefix4, addr, sizeof(struct in_addr));
		p->prefixlen = IPV4_MAX_BITLEN;
		addr += sizeof(struct in_addr);

		break;
	case PIM_MSG_ADDRESS_FAMILY_IPV6:
		if ((addr + sizeof(struct in6_addr)) > pastend) {
			zlog_warn(
				"%s: IPv6 unicast address overflow: left=%td needed %zu",
				__func__, pastend - addr,
				sizeof(struct in6_addr));
			return -3;
		}

		p->family = AF_INET6;
		p->prefixlen = IPV6_MAX_BITLEN;
		memcpy(&p->u.prefix6, addr, sizeof(struct in6_addr));
		addr += sizeof(struct in6_addr);

		break;
	default: {
		zlog_warn("%s: unknown unicast address encoding family=%d from",
			  __func__, family);
		return -4;
	}
	}

	return addr - buf;
}

int pim_parse_addr_ucast(pim_addr *out, const uint8_t *buf, int buf_size,
			 bool *wrong_af)
{
	struct prefix p;
	int ret;

	ret = pim_parse_addr_ucast_prefix(&p, buf, buf_size);
	if (ret < 0)
		return ret;

	if (p.family != PIM_AF) {
		*wrong_af = true;
		return -5;
	}

	memcpy(out, &p.u.val, sizeof(*out));
	return ret;
}

int pim_parse_addr_group(pim_sgaddr *sg, const uint8_t *buf, int buf_size)
{
	const int grp_encoding_min_len =
		4; /* 1 family + 1 type + 1 reserved + 1 addr */
	const uint8_t *addr;
	const uint8_t *pastend;
	int family;
	int type;
	int mask_len;

	if (buf_size < grp_encoding_min_len) {
		zlog_warn(
			"%s: group address encoding overflow: left=%d needed=%d",
			__func__, buf_size, grp_encoding_min_len);
		return -1;
	}

	addr = buf;
	pastend = buf + buf_size;

	family = *addr++;
	type = *addr++;
	++addr; /* skip b_reserved_z fields */
	mask_len = *addr++;

	if (type) {
		zlog_warn("%s: unknown group address encoding type=%d from",
			  __func__, type);
		return -2;
	}

	if (family != PIM_MSG_ADDRESS_FAMILY) {
		zlog_warn(
			"%s: unknown group address encoding family=%d mask_len=%d from",
			__func__, family, mask_len);
		return -4;
	}

	if ((addr + sizeof(sg->grp)) > pastend) {
		zlog_warn(
			"%s: group address overflow: left=%td needed=%zu from",
			__func__, pastend - addr, sizeof(sg->grp));
		return -3;
	}

	memcpy(&sg->grp, addr, sizeof(sg->grp));
	addr += sizeof(sg->grp);

	return addr - buf;
}

int pim_parse_addr_source(pim_sgaddr *sg, uint8_t *flags, const uint8_t *buf,
			  int buf_size)
{
	const int src_encoding_min_len =
		4; /* 1 family + 1 type + 1 reserved + 1 addr */
	const uint8_t *addr;
	const uint8_t *pastend;
	int family;
	int type;
	int mask_len;

	if (buf_size < src_encoding_min_len) {
		zlog_warn(
			"%s: source address encoding overflow: left=%d needed=%d",
			__func__, buf_size, src_encoding_min_len);
		return -1;
	}

	addr = buf;
	pastend = buf + buf_size;

	family = *addr++;
	type = *addr++;
	*flags = *addr++;
	mask_len = *addr++;

	if (type) {
		zlog_warn(
			"%s: unknown source address encoding type=%d: %02x%02x%02x%02x",
			__func__, type, buf[0], buf[1], buf[2], buf[3]);
		return -2;
	}

	switch (family) {
	case PIM_MSG_ADDRESS_FAMILY:
		if ((addr + sizeof(sg->src)) > pastend) {
			zlog_warn(
				"%s: IP source address overflow: left=%td needed=%zu",
				__func__, pastend - addr, sizeof(sg->src));
			return -3;
		}

		memcpy(&sg->src, addr, sizeof(sg->src));

		/*
		   RFC 4601: 4.9.1  Encoded Source and Group Address Formats

		   Encoded-Source Address

		   The mask length MUST be equal to the mask length in bits for
		   the given Address Family and Encoding Type (32 for IPv4
		   native and 128 for IPv6 native).  A router SHOULD ignore any
		   messages received with any other mask length.
		*/
		if (mask_len != PIM_MAX_BITLEN) {
			zlog_warn("%s: IP bad source address mask: %d",
				  __func__, mask_len);
			return -4;
		}

		addr += sizeof(sg->src);

		break;
	default:
		zlog_warn(
			"%s: unknown source address encoding family=%d: %02x%02x%02x%02x",
			__func__, family, buf[0], buf[1], buf[2], buf[3]);
		return -5;
	}

	return addr - buf;
}

#define FREE_ADDR_LIST(hello_option_addr_list)                                 \
	{                                                                      \
		if (hello_option_addr_list) {                                  \
			list_delete(&hello_option_addr_list);                  \
			hello_option_addr_list = 0;                            \
		}                                                              \
	}

int pim_tlv_parse_addr_list(const char *ifname, pim_addr src_addr,
			    pim_hello_options *hello_options,
			    struct list **hello_option_addr_list,
			    uint16_t option_len, const uint8_t *tlv_curr)
{
	const uint8_t *addr;
	const uint8_t *pastend;

	assert(hello_option_addr_list);

	/*
	  Scan addr list
	 */
	addr = tlv_curr;
	pastend = tlv_curr + option_len;
	while (addr < pastend) {
		struct prefix tmp, src_pfx;
		int addr_offset;

		/*
		  Parse ucast addr
		 */
		addr_offset =
			pim_parse_addr_ucast_prefix(&tmp, addr, pastend - addr);
		if (addr_offset < 1) {
			zlog_warn(
				"%s: pim_parse_addr_ucast() failure: from %pPAs on %s",
				__func__, &src_addr, ifname);
			FREE_ADDR_LIST(*hello_option_addr_list);
			return -1;
		}
		addr += addr_offset;

		/*
		  Debug
		 */
		if (PIM_DEBUG_PIM_TRACE) {
			switch (tmp.family) {
			case AF_INET: {
				char addr_str[INET_ADDRSTRLEN];
				pim_inet4_dump("<addr?>", tmp.u.prefix4,
					       addr_str, sizeof(addr_str));
				zlog_debug(
					"%s: PIM hello TLV option: list_old_size=%d IPv4 address %s from %pPAs on %s",
					__func__,
					*hello_option_addr_list
						? ((int)listcount(
							  *hello_option_addr_list))
						: -1,
					addr_str, &src_addr, ifname);
			} break;
			case AF_INET6:
				break;
			default:
				zlog_debug(
					"%s: PIM hello TLV option: list_old_size=%d UNKNOWN address family from %pPAs on %s",
					__func__,
					*hello_option_addr_list
						? ((int)listcount(
							  *hello_option_addr_list))
						: -1,
					&src_addr, ifname);
			}
		}

		/*
		  Exclude neighbor's primary address if incorrectly included in
		  the secondary address list
		 */
		pim_addr_to_prefix(&src_pfx, src_addr);
		if (!prefix_cmp(&tmp, &src_pfx)) {
			zlog_warn(
				"%s: ignoring primary address in secondary list from %pPAs on %s",
				__func__, &src_addr, ifname);
			continue;
		}

		/*
		  Allocate list if needed
		 */
		if (!*hello_option_addr_list) {
			*hello_option_addr_list = list_new();
			(*hello_option_addr_list)->del = prefix_free_lists;
		}

		/*
		  Attach addr to list
		 */
		{
			struct prefix *p;
			p = prefix_new();
			prefix_copy(p, &tmp);
			listnode_add(*hello_option_addr_list, p);
		}

	} /* while (addr < pastend) */

	/*
	  Mark hello option
	 */
	PIM_OPTION_SET(*hello_options, PIM_OPTION_MASK_ADDRESS_LIST);

	return 0;
}