strace/rtnl_route.c

/*
 * Copyright (c) 2016 Fabien Siron <fabien.siron@epita.fr>
 * Copyright (c) 2017 JingPiao Chen <chenjingpiao@gmail.com>
 * Copyright (c) 2016-2018 The strace developers.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "defs.h"
#include "netlink_route.h"
#include "nlattr.h"
#include "print_fields.h"

#include <linux/ip.h>
#include "netlink.h"
#include <linux/rtnetlink.h>

#include "xlat/ip_type_of_services.h"
#include "xlat/lwtunnel_encap_types.h"
#include "xlat/route_nexthop_flags.h"
#include "xlat/routing_flags.h"
#include "xlat/routing_protocols.h"
#include "xlat/routing_table_ids.h"
#include "xlat/routing_types.h"
#include "xlat/rtnl_route_attrs.h"
#include "xlat/rtnl_rta_metrics_attrs.h"

bool
decode_nla_rt_class(struct tcb *const tcp,
		    const kernel_ulong_t addr,
		    const unsigned int len,
		    const void *const opaque_data)
{
	uint32_t num;

	if (len < sizeof(num))
		return false;
	if (!umove_or_printaddr(tcp, addr, &num))
		printxval(routing_table_ids, num, NULL);
	return true;
}

static bool
decode_route_addr(struct tcb *const tcp,
		  const kernel_ulong_t addr,
		  const unsigned int len,
		  const void *const opaque_data)
{
	const struct rtmsg *const rtmsg = opaque_data;

	decode_inet_addr(tcp, addr, len, rtmsg->rtm_family, NULL);

	return true;
}

static const nla_decoder_t rta_metrics_nla_decoders[] = {
	[RTAX_LOCK]		= decode_nla_u32,
	[RTAX_MTU]		= decode_nla_u32,
	[RTAX_WINDOW]		= decode_nla_u32,
	[RTAX_RTT]		= decode_nla_u32,
	[RTAX_RTTVAR]		= decode_nla_u32,
	[RTAX_SSTHRESH]		= decode_nla_u32,
	[RTAX_CWND]		= decode_nla_u32,
	[RTAX_ADVMSS]		= decode_nla_u32,
	[RTAX_REORDERING]	= decode_nla_u32,
	[RTAX_HOPLIMIT]		= decode_nla_u32,
	[RTAX_INITCWND]		= decode_nla_u32,
	[RTAX_FEATURES]		= decode_nla_u32,
	[RTAX_RTO_MIN]		= decode_nla_u32,
	[RTAX_INITRWND]		= decode_nla_u32,
	[RTAX_QUICKACK]		= decode_nla_u32,
	[RTAX_CC_ALGO]		= decode_nla_str
};

static bool
decode_rta_metrics(struct tcb *const tcp,
		   const kernel_ulong_t addr,
		   const unsigned int len,
		   const void *const opaque_data)
{
	decode_nlattr(tcp, addr, len, rtnl_rta_metrics_attrs,
		      "RTAX_???", rta_metrics_nla_decoders,
		      ARRAY_SIZE(rta_metrics_nla_decoders), opaque_data);

	return true;
}

static bool
decode_rta_multipath(struct tcb *const tcp,
		     const kernel_ulong_t addr,
		     const unsigned int len,
		     const void *const opaque_data);

static bool
decode_rta_cacheinfo(struct tcb *const tcp,
		     const kernel_ulong_t addr,
		     const unsigned int len,
		     const void *const opaque_data)
{
	struct rta_cacheinfo ci;

	if (len < sizeof(ci))
		return false;
	else if (!umove_or_printaddr(tcp, addr, &ci)) {
		PRINT_FIELD_U("{", ci, rta_clntref);
		PRINT_FIELD_U(", ", ci, rta_lastuse);
		PRINT_FIELD_U(", ", ci, rta_expires);
		PRINT_FIELD_U(", ", ci, rta_error);
		PRINT_FIELD_U(", ", ci, rta_used);
		PRINT_FIELD_X(", ", ci, rta_id);
		PRINT_FIELD_U(", ", ci, rta_ts);
		PRINT_FIELD_U(", ", ci, rta_tsage);
		tprints("}");
	}

	return true;
}

static bool
decode_rta_mfc_stats(struct tcb *const tcp,
		     const kernel_ulong_t addr,
		     const unsigned int len,
		     const void *const opaque_data)
{
#ifdef HAVE_STRUCT_RTA_MFC_STATS
	struct rta_mfc_stats mfcs;

	if (len < sizeof(mfcs))
		return false;
	else if (!umove_or_printaddr(tcp, addr, &mfcs)) {
		PRINT_FIELD_U("{", mfcs, mfcs_packets);
		PRINT_FIELD_U(", ", mfcs, mfcs_bytes);
		PRINT_FIELD_U(", ", mfcs, mfcs_wrong_if);
		tprints("}");
	}

	return true;
#else
	return false;
#endif
}

static bool
decode_rtvia(struct tcb *const tcp,
	     const kernel_ulong_t addr,
	     const unsigned int len,
	     const void *const opaque_data)
{
#ifdef HAVE_STRUCT_RTVIA
	struct rtvia via;

	if (len < sizeof(via))
		return false;
	else if (!umove_or_printaddr(tcp, addr, &via)) {
		PRINT_FIELD_XVAL("{", via, rtvia_family, addrfams, "AF_???");

		const unsigned int offset = offsetof(struct rtvia, rtvia_addr);

		if (len > offset) {
			tprints(", ");
			decode_inet_addr(tcp, addr + offset, len - offset,
					 via.rtvia_family, "rtvia_addr");
		}
		tprints("}");
	}

	return true;
#else
	return false;
#endif
}

static bool
decode_rta_encap_type(struct tcb *const tcp,
		      const kernel_ulong_t addr,
		      const unsigned int len,
		      const void *const opaque_data)
{
	uint16_t type;

	if (len < sizeof(type))
		return false;
	else if (!umove_or_printaddr(tcp, addr, &type))
		printxval(lwtunnel_encap_types, type, "LWTUNNEL_ENCAP_???");

	return true;
}

static const nla_decoder_t rtmsg_nla_decoders[] = {
	[RTA_DST]		= decode_route_addr,
	[RTA_SRC]		= decode_route_addr,
	[RTA_IIF]		= decode_nla_ifindex,
	[RTA_OIF]		= decode_nla_ifindex,
	[RTA_GATEWAY]		= decode_route_addr,
	[RTA_PRIORITY]		= decode_nla_u32,
	[RTA_PREFSRC]		= decode_route_addr,
	[RTA_METRICS]		= decode_rta_metrics,
	[RTA_MULTIPATH]		= decode_rta_multipath,
	[RTA_PROTOINFO]		= decode_nla_u32,
	[RTA_FLOW]		= decode_nla_u32,
	[RTA_CACHEINFO]		= decode_rta_cacheinfo,
	[RTA_SESSION]		= NULL, /* unused */
	[RTA_MP_ALGO]		= decode_nla_u32,
	[RTA_TABLE]		= decode_nla_rt_class,
	[RTA_MARK]		= decode_nla_u32,
	[RTA_MFC_STATS]		= decode_rta_mfc_stats,
	[RTA_VIA]		= decode_rtvia,
	[RTA_NEWDST]		= decode_route_addr,
	[RTA_PREF]		= decode_nla_u8,
	[RTA_ENCAP_TYPE]	= decode_rta_encap_type,
	[RTA_ENCAP]		= NULL, /* unimplemented */
	[RTA_EXPIRES]		= decode_nla_u64,
	[RTA_PAD]		= NULL,
	[RTA_UID]		= decode_nla_u32,
	[RTA_TTL_PROPAGATE]	= decode_nla_u8
};

static bool
decode_rta_multipath(struct tcb *const tcp,
		     const kernel_ulong_t addr,
		     const unsigned int len,
		     const void *const opaque_data)
{
	struct rtnexthop nh;

	if (len < sizeof(nh))
		return false;
	else if (!umove_or_printaddr(tcp, addr, &nh)) {
		/* print the whole structure regardless of its rtnh_len */
		PRINT_FIELD_U("{", nh, rtnh_len);
		PRINT_FIELD_FLAGS(", ", nh, rtnh_flags,
				  route_nexthop_flags, "RTNH_F_???");
		PRINT_FIELD_U(", ", nh, rtnh_hops);
		PRINT_FIELD_IFINDEX(", ", nh, rtnh_ifindex);
		tprints("}");

		const unsigned short rtnh_len =
			len < nh.rtnh_len ? len : nh.rtnh_len;
		const size_t offset = RTNH_ALIGN(sizeof(nh));
		if (rtnh_len > offset) {
			tprints(", ");
			decode_nlattr(tcp, addr + offset, rtnh_len - offset,
				      rtnl_route_attrs, "RTA_???",
				      rtmsg_nla_decoders,
				      ARRAY_SIZE(rtmsg_nla_decoders),
				      opaque_data);
		}
	}

	return true;
}

DECL_NETLINK_ROUTE_DECODER(decode_rtmsg)
{
	struct rtmsg rtmsg = { .rtm_family = family };
	size_t offset = sizeof(rtmsg.rtm_family);
	bool decode_nla = false;

	PRINT_FIELD_XVAL("{", rtmsg, rtm_family, addrfams, "AF_???");

	tprints(", ");
	if (len >= sizeof(rtmsg)) {
		if (!umoven_or_printaddr(tcp, addr + offset,
					 sizeof(rtmsg) - offset,
					 (char *) &rtmsg + offset)) {
			PRINT_FIELD_U("", rtmsg, rtm_dst_len);
			PRINT_FIELD_U(", ", rtmsg, rtm_src_len);
			PRINT_FIELD_FLAGS(", ", rtmsg, rtm_tos,
					  ip_type_of_services, "IPTOS_TOS_???");
			PRINT_FIELD_XVAL(", ", rtmsg, rtm_table,
					 routing_table_ids, NULL);
			PRINT_FIELD_XVAL(", ", rtmsg, rtm_protocol,
					 routing_protocols, "RTPROT_???");
			PRINT_FIELD_XVAL(", ", rtmsg, rtm_scope,
					 routing_scopes, NULL);
			PRINT_FIELD_XVAL(", ", rtmsg, rtm_type,
					 routing_types, "RTN_???");
			PRINT_FIELD_FLAGS(", ", rtmsg, rtm_flags,
					  routing_flags, "RTM_F_???");
			decode_nla = true;
		}
	} else
		tprints("...");
	tprints("}");

	offset = NLMSG_ALIGN(sizeof(rtmsg));
	if (decode_nla && len > offset) {
		tprints(", ");
		decode_nlattr(tcp, addr + offset, len - offset,
			      rtnl_route_attrs, "RTA_???",
			      rtmsg_nla_decoders,
			      ARRAY_SIZE(rtmsg_nla_decoders), &rtmsg);
	}
}