/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 */

/*
 * Route-related (RTM_<NEW|DEL|GET>ROUTE) message header and attributes.
 */

#ifndef _NETLINK_ROUTE_ROUTE_H_
#define _NETLINK_ROUTE_ROUTE_H_

/* Base header for all of the relevant messages */
struct rtmsg {
        unsigned char   rtm_family;     /* address family */
        unsigned char   rtm_dst_len;    /* Prefix length */
        unsigned char   rtm_src_len;    /* Source prefix length (not used) */
        unsigned char   rtm_tos;        /* Type of service (not used) */
        unsigned char   rtm_table;      /* rtable id */
        unsigned char   rtm_protocol;   /* Routing protocol id (RTPROT_) */
        unsigned char   rtm_scope;      /* Route distance (RT_SCOPE_) */
        unsigned char   rtm_type;       /* Route type (RTN_) */
        unsigned        rtm_flags;      /* Route flags (RTM_F_) */
};

/*
 * RFC 3549, 3.1.1, route type (rtm_type field).
 */
enum {
        RTN_UNSPEC,
        RTN_UNICAST,            /* Unicast route */
        RTN_LOCAL,              /* Accept locally (not supported) */
        RTN_BROADCAST,          /* Accept locally as broadcast, send as broadcast */
        RTN_ANYCAST,            /* Accept locally as broadcast, but send as unicast */
        RTN_MULTICAST,          /* Multicast route */
        RTN_BLACKHOLE,          /* Drop traffic towards destination */
        RTN_UNREACHABLE,        /* Destination is unreachable */
        RTN_PROHIBIT,           /* Administratively prohibited */
        RTN_THROW,              /* Not in this table (not supported) */
        RTN_NAT,                /* Translate this address (not supported) */
        RTN_XRESOLVE,           /* Use external resolver (not supported) */
        __RTN_MAX,
};
#define RTN_MAX (__RTN_MAX - 1)

/*
 * RFC 3549, 3.1.1, protocol (Identifies what/who added the route).
 * Values larger than RTPROT_STATIC(4) are not interpreted by the
 * kernel, they are just for user information.
 */
#define RTPROT_UNSPEC           0
#define RTPROT_REDIRECT         1 /* Route installed by ICMP redirect */
#define RTPROT_KERNEL           2 /* Route installed by kernel */
#define RTPROT_BOOT             3 /* Route installed during boot */
#define RTPROT_STATIC           4 /* Route installed by administrator */

#define RTPROT_GATED            8
#define RTPROT_RA               9
#define RTPROT_MRT              1
#define RTPROT_ZEBRA            11
#define RTPROT_BIRD             12
#define RTPROT_DNROUTED         13
#define RTPROT_XORP             14
#define RTPROT_NTK              15
#define RTPROT_DHCP             16
#define RTPROT_MROUTED          17
#define RTPROT_KEEPALIVED       18
#define RTPROT_BABEL            42
#define RTPROT_OPENR            99
#define RTPROT_BGP              186
#define RTPROT_ISIS             187
#define RTPROT_OSPF             188
#define RTPROT_RIP              189
#define RTPROT_EIGRP            192

/*
 * RFC 3549 3.1.1 Route scope (valid distance to destination).
 *
 * The values between RT_SCOPE_UNIVERSE(0) and RT_SCOPE_SITE(200)
 *  are available to the user.
 */
enum rt_scope_t {
        RT_SCOPE_UNIVERSE = 0,
        /* User defined values  */
        RT_SCOPE_SITE = 200,
        RT_SCOPE_LINK = 253,
        RT_SCOPE_HOST = 254,
        RT_SCOPE_NOWHERE = 255
};

/*
 * RFC 3549 3.1.1 Route flags (rtm_flags).
 * Is a composition of RTNH_F flags (0x1..0x40 range), RTM_F flags (below)
 * and per-protocol (IPv4/IPv6) flags.
 */
#define RTM_F_NOTIFY            0x00000100 /* not supported */
#define RTM_F_CLONED            0x00000200 /* not supported */
#define RTM_F_EQUALIZE          0x00000400 /* not supported */
#define RTM_F_PREFIX            0x00000800 /* not supported */
#define RTM_F_LOOKUP_TABLE      0x00001000 /* not supported */
#define RTM_F_FIB_MATCH         0x00002000 /* not supported */
#define RTM_F_OFFLOAD           0x00004000 /* not supported */
#define RTM_F_TRAP              0x00008000 /* not supported */
#define RTM_F_OFFLOAD_FAILED    0x20000000 /* not supported */

/* Compatibility handling helpers */
#ifndef _KERNEL
#define NL_RTM_HDRLEN           ((int)sizeof(struct rtmsg))
#define RTM_RTA(_rtm)           ((struct rtattr *)((char *)(_rtm) + NL_RTM_HDRLEN))
#define RTM_PAYLOAD(_hdr)       NLMSG_PAYLOAD((_hdr), NL_RTM_HDRLEN)
#endif

/*
 * Routing table identifiers.
 * FreeBSD route table numbering starts from 0, where 0 is a valid default
 * routing table.  Indicating "all tables" via netlink can be done by not
 * including RTA_TABLE attribute and keeping rtm_table=0 (compatibility) or
 * setting RTA_TABLE value to RT_TABLE_UNSPEC.
 */
#define RT_TABLE_MAIN   0               /* RT_DEFAULT_FIB */
#define RT_TABLE_UNSPEC 0xFFFFFFFF      /* RT_ALL_FIBS */

enum rtattr_type_t {
        NL_RTA_UNSPEC,
        NL_RTA_DST              = 1, /* binary, IPv4/IPv6 destination */
        NL_RTA_SRC              = 2, /* not supported */
        NL_RTA_IIF              = 3, /* not supported */
        NL_RTA_OIF              = 4, /* u32, transmit ifindex */
        NL_RTA_GATEWAY          = 5, /* binary: IPv4/IPv6 gateway */
        NL_RTA_PRIORITY         = 6, /* u32, path metric */
        NL_RTA_PREFSRC          = 7, /* binary, preferred source address */
        NL_RTA_METRICS          = 8, /* nested, list of NL_RTAX* attrs */
        NL_RTA_MULTIPATH        = 9, /* binary, array of struct rtnexthop */
        NL_RTA_PROTOINFO        = 10, /* not supported / deprecated */
        NL_RTA_KNH_ID           = 10, /* u32, FreeBSD specific, kernel nexthop index */
        NL_RTA_FLOW             = 11, /* not supported */
        NL_RTA_CACHEINFO        = 12, /* not supported */
        NL_RTA_SESSION          = 13, /* not supported / deprecated */
        NL_RTA_WEIGHT           = 13, /* u32, FreeBSD specific, path weight */
        NL_RTA_MP_ALGO          = 14, /* not supported / deprecated */
        NL_RTA_RTFLAGS          = 14, /* u32, FreeBSD specific, path flags (RTF_)*/
        NL_RTA_TABLE            = 15, /* u32, fibnum */
        NL_RTA_MARK             = 16, /* not supported */
        NL_RTA_MFC_STATS        = 17, /* not supported */
        NL_RTA_VIA              = 18, /* binary, struct rtvia */
        NL_RTA_NEWDST           = 19, /* not supported */
        NL_RTA_PREF             = 20, /* not supported */
        NL_RTA_ENCAP_TYPE       = 21, /* not supported */
        NL_RTA_ENCAP            = 22, /* not supported */
        NL_RTA_EXPIRES          = 23, /* u32, seconds till expiration */
        NL_RTA_PAD              = 24, /* not supported */
        NL_RTA_UID              = 25, /* not supported */
        NL_RTA_TTL_PROPAGATE    = 26, /* not supported */
        NL_RTA_IP_PROTO         = 27, /* not supported */
        NL_RTA_SPORT            = 28, /* not supported */
        NL_RTA_DPORT            = 29, /* not supported */
        NL_RTA_NH_ID            = 30, /* u32, nexthop/nexthop group index */
        __RTA_MAX
};
#define NL_RTA_MAX (__RTA_MAX - 1)

/*
 * Attributes that can be used as filters:
 *
 */

#ifndef _KERNEL
/*
 * RTA_* space has clashes with rtsock namespace.
 * Use NL_RTA_ prefix in the kernel and map to
 * RTA_ for userland.
 */
#define RTA_UNSPEC              NL_RTA_UNSPEC
#define RTA_DST                 NL_RTA_DST
#define RTA_SRC                 NL_RTA_SRC
#define RTA_IIF                 NL_RTA_IIF
#define RTA_OIF                 NL_RTA_OIF
#define RTA_GATEWAY             NL_RTA_GATEWAY
#define RTA_PRIORITY            NL_RTA_PRIORITY
#define RTA_PREFSRC             NL_RTA_PREFSRC
#define RTA_IFA                 NL_RTA_PREFSRC
#define RTA_METRICS             NL_RTA_METRICS
#define RTA_MULTIPATH           NL_RTA_MULTIPATH
#define RTA_PROTOINFO           NL_RTA_PROTOINFO
#define RTA_KNH_ID              NL_RTA_KNH_ID
#define RTA_FLOW                NL_RTA_FLOW
#define RTA_CACHEINFO           NL_RTA_CACHEINFO
#define RTA_SESSION             NL_RTA_SESSION
#define RTA_MP_ALGO             NL_RTA_MP_ALGO
#define RTA_TABLE               NL_RTA_TABLE
#define RTA_MARK                NL_RTA_MARK
#define RTA_MFC_STATS           NL_RTA_MFC_STATS
#define RTA_VIA                 NL_RTA_VIA
#define RTA_NEWDST              NL_RTA_NEWDST
#define RTA_PREF                NL_RTA_PREF
#define RTA_ENCAP_TYPE          NL_RTA_ENCAP_TYPE
#define RTA_ENCAP               NL_RTA_ENCAP
#define RTA_EXPIRES             NL_RTA_EXPIRES
#define RTA_PAD                 NL_RTA_PAD
#define RTA_UID                 NL_RTA_UID
#define RTA_TTL_PROPAGATE       NL_RTA_TTL_PROPAGATE
#define RTA_IP_PROTO            NL_RTA_IP_PROTO
#define RTA_SPORT               NL_RTA_SPORT
#define RTA_DPORT               NL_RTA_DPORT
#define RTA_NH_ID               NL_RTA_NH_ID
#define RTA_MAX                 NL_RTA_MAX
#endif

/* route attribute header */
struct rtattr {
        unsigned short rta_len;
        unsigned short rta_type;
};

#define NL_RTA_ALIGN_SIZE       NL_ITEM_ALIGN_SIZE
#define NL_RTA_ALIGN            NL_ITEM_ALIGN
#define NL_RTA_HDRLEN           ((int)sizeof(struct rtattr))
#define NL_RTA_DATA_LEN(_rta)   ((int)((_rta)->rta_len - NL_RTA_HDRLEN))
#define NL_RTA_DATA(_rta)       NL_ITEM_DATA(_rta, NL_RTA_HDRLEN)
#define NL_RTA_DATA_CONST(_rta) NL_ITEM_DATA_CONST(_rta, NL_RTA_HDRLEN)

/* Compatibility attribute handling helpers */
#ifndef _KERNEL
#define RTA_ALIGNTO             NL_RTA_ALIGN_SIZE
#define RTA_ALIGN(_len)         NL_RTA_ALIGN(_len)
#define _RTA_LEN(_rta)          ((int)(_rta)->rta_len)
#define _RTA_ALIGNED_LEN(_rta)  RTA_ALIGN(_RTA_LEN(_rta))
#define RTA_OK(_rta, _len)      NL_ITEM_OK(_rta, _len, NL_RTA_HDRLEN, _RTA_LEN)
#define RTA_NEXT(_rta, _len)    NL_ITEM_ITER(_rta, _len, _RTA_ALIGNED_LEN)
#define RTA_LENGTH(_len)        (NL_RTA_HDRLEN + (_len))
#define RTA_SPACE(_len)         RTA_ALIGN(RTA_LENGTH(_len))
#define RTA_DATA(_rta)          NL_RTA_DATA(_rta)
#define RTA_PAYLOAD(_rta)       ((int)(_RTA_LEN(_rta) - NL_RTA_HDRLEN))
#endif

/* RTA attribute headers */

/* RTA_VIA */
struct rtvia {
        sa_family_t     rtvia_family;
        uint8_t         rtvia_addr[0];
};

/*
 * RTA_METRICS is a nested attribute, consisting of a list of
 * TLVs with types defined below.
 */
 enum {
        NL_RTAX_UNSPEC,
        NL_RTAX_LOCK                    = 1, /* not supported */
        NL_RTAX_MTU                     = 2, /* desired path MTU */
        NL_RTAX_WINDOW                  = 3, /* not supported */
        NL_RTAX_RTT                     = 4, /* not supported */
        NL_RTAX_RTTVAR                  = 5, /* not supported */
        NL_RTAX_SSTHRESH                = 6, /* not supported */
        NL_RTAX_CWND                    = 7, /* not supported */
        NL_RTAX_ADVMSS                  = 8, /* not supported  */
        NL_RTAX_REORDERING              = 9, /* not supported */
        NL_RTAX_HOPLIMIT                = 10, /* not supported */
        NL_RTAX_INITCWND                = 11, /* not supporrted */
        NL_RTAX_FEATURES                = 12, /* not supported */
        NL_RTAX_RTO_MIN                 = 13, /* not supported */
        NL_RTAX_INITRWND                = 14, /* not supported */
        NL_RTAX_QUICKACK                = 15, /* not supported */
        NL_RTAX_CC_ALGO                 = 16, /* not supported */
        NL_RTAX_FASTOPEN_NO_COOKIE      = 17, /* not supported */
        __NL_RTAX_MAX
};
#define NL_RTAX_MAX (__NL_RTAX_MAX - 1)

#define RTAX_FEATURE_ECN (1 << 0)
#define RTAX_FEATURE_SACK (1 << 1)
#define RTAX_FEATURE_TIMESTAMP (1 << 2)
#define RTAX_FEATURE_ALLFRAG (1 << 3)

#define RTAX_FEATURE_MASK                                                \
        (RTAX_FEATURE_ECN | RTAX_FEATURE_SACK | RTAX_FEATURE_TIMESTAMP | \
            RTAX_FEATURE_ALLFRAG)

#ifndef _KERNEL

/*
 * RTAX_* space clashes with rtsock namespace.
 * Use NL_RTAX_ prefix in the kernel and map to
 * RTAX_ for userland.
 */
#define RTAX_UNSPEC             NL_RTAX_UNSPEC
#define RTAX_LOCK               NL_RTAX_LOCK
#define RTAX_MTU                NL_RTAX_MTU
#define RTAX_WINDOW             NL_RTAX_WINDOW
#define RTAX_RTT                NL_RTAX_RTT
#define RTAX_RTTVAR             NL_RTAX_RTTVAR
#define RTAX_SSTHRESH           NL_RTAX_SSTHRESH
#define RTAX_CWND               NL_RTAX_CWND
#define RTAX_ADVMSS             NL_RTAX_ADVMSS
#define RTAX_REORDERING         NL_RTAX_REORDERING
#define RTAX_HOPLIMIT           NL_RTAX_HOPLIMIT
#define RTAX_INITCWND           NL_RTAX_INITCWND
#define RTAX_FEATURES           NL_RTAX_FEATURES
#define RTAX_RTO_MIN            NL_RTAX_RTO_MIN
#define RTAX_INITRWND           NL_RTAX_INITRWND
#define RTAX_QUICKACK           NL_RTAX_QUICKACK
#define RTAX_CC_ALGO            NL_RTAX_CC_ALGO
#define RTAX_FASTOPEN_NO_COOKIE NL_RTAX_FASTOPEN_NO_COOKIE
#endif

/*
 * RTA_MULTIPATH consists of an array of rtnexthop structures.
 * Each rtnexthop structure contains RTA_GATEWAY or RTA_VIA
 * attribute following the header.
 */
struct rtnexthop {
        unsigned short          rtnh_len;
        unsigned char           rtnh_flags;
        unsigned char           rtnh_hops;      /* nexthop weight */
        int                     rtnh_ifindex;
};

/* rtnh_flags */
#define RTNH_F_DEAD             0x01    /* not supported */
#define RTNH_F_PERVASIVE        0x02    /* not supported */
#define RTNH_F_ONLINK           0x04    /* not supported */
#define RTNH_F_OFFLOAD          0x08    /* not supported */
#define RTNH_F_LINKDOWN         0x10    /* not supported */
#define RTNH_F_UNRESOLVED       0x20    /* not supported */
#define RTNH_F_TRAP             0x40    /* not supported */

#define RTNH_COMPARE_MASK       (RTNH_F_DEAD | RTNH_F_LINKDOWN | \
                                 RTNH_F_OFFLOAD | RTNH_F_TRAP)

/* Macros to handle hexthops */
#define RTNH_ALIGNTO            NL_ITEM_ALIGN_SIZE
#define RTNH_ALIGN(_len)        NL_ITEM_ALIGN(_len)
#define RTNH_HDRLEN             ((int)sizeof(struct rtnexthop))
#define _RTNH_LEN(_nh)          ((int)(_nh)->rtnh_len)
#define _RTNH_ALIGNED_LEN(_nh)  RTNH_ALIGN(_RTNH_LEN(_nh))
#define RTNH_OK(_nh, _len)      NL_ITEM_OK(_nh, _len, RTNH_HDRLEN, _RTNH_LEN)
#define RTNH_NEXT(_nh)          ((struct rtnexthop *)((char *)(_nh) + _RTNH_ALIGNED_LEN(_nh)))
#define RTNH_LENGTH(_len)       (RTNH_HDRLEN + (_len))
#define RTNH_SPACE(_len)        RTNH_ALIGN(RTNH_LENGTH(_len))
#define RTNH_DATA(_nh)          ((struct rtattr *)NL_ITEM_DATA(_nh, RTNH_HDRLEN))

struct rtgenmsg {
        unsigned char rtgen_family;
};

#endif