root/usr.sbin/ldpd/parse.y
/*      $OpenBSD: parse.y,v 1.74 2024/08/22 08:17:54 florian Exp $ */

/*
 * Copyright (c) 2013, 2015, 2016 Renato Westphal <renato@openbsd.org>
 * Copyright (c) 2004, 2005, 2008 Esben Norby <norby@openbsd.org>
 * Copyright (c) 2004 Ryan McBride <mcbride@openbsd.org>
 * Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
 * Copyright (c) 2001 Daniel Hartmeier.  All rights reserved.
 * Copyright (c) 2001 Theo de Raadt.  All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

%{
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <err.h>
#include <unistd.h>
#include <ifaddrs.h>
#include <net/if_types.h>
#include <limits.h>
#include <stdio.h>
#include <syslog.h>
#include <errno.h>
#include <netdb.h>

#include "ldpd.h"
#include "ldpe.h"
#include "lde.h"
#include "log.h"

struct file {
        TAILQ_ENTRY(file)        entry;
        FILE                    *stream;
        char                    *name;
        size_t                   ungetpos;
        size_t                   ungetsize;
        u_char                  *ungetbuf;
        int                      eof_reached;
        int                      lineno;
        int                      errors;
};
TAILQ_HEAD(files, file);

struct sym {
        TAILQ_ENTRY(sym)         entry;
        int                      used;
        int                      persist;
        char                    *nam;
        char                    *val;
};
TAILQ_HEAD(symhead, sym);

struct config_defaults {
        uint16_t        keepalive;
        uint16_t        lhello_holdtime;
        uint16_t        lhello_interval;
        uint16_t        thello_holdtime;
        uint16_t        thello_interval;
        union ldpd_addr trans_addr;
        int             afflags;
        uint8_t         pwflags;
};

typedef struct {
        union {
                int64_t          number;
                char            *string;
                struct in_addr   routerid;
                struct ldp_auth *auth;
        } v;
        int lineno;
} YYSTYPE;

static int               yyerror(const char *, ...)
    __attribute__((__format__ (printf, 1, 2)))
    __attribute__((__nonnull__ (1)));
static int               kw_cmp(const void *, const void *);
static int               lookup(char *);
static int               igetc(void);
static int               lgetc(int);
void                     lungetc(int);
static int               findeol(void);
static int               yylex(void);
static int               check_file_secrecy(int, const char *);
static struct file      *pushfile(const char *, int);
static int               popfile(void);
static int               yyparse(void);
static int               symset(const char *, const char *, int);
static char             *symget(const char *);
static struct iface     *conf_get_if(struct kif *);
static struct tnbr      *conf_get_tnbr(union ldpd_addr *);
static struct nbr_params *conf_get_nbrp(struct in_addr);
static struct l2vpn     *conf_get_l2vpn(char *);
static struct l2vpn_if  *conf_get_l2vpn_if(struct l2vpn *, struct kif *);
static struct l2vpn_pw  *conf_get_l2vpn_pw(struct l2vpn *, struct kif *);
int                      conf_check_rdomain(unsigned int);
static void              clear_config(struct ldpd_conf *xconf);
static uint32_t          get_rtr_id(void);
static int               get_address(const char *, union ldpd_addr *);
static int               get_af_address(const char *, int *, union ldpd_addr *);
static int               str2key(char *, const char *, int);

static struct file              *file, *topfile;
static struct files              files = TAILQ_HEAD_INITIALIZER(files);
static struct symhead            symhead = TAILQ_HEAD_INITIALIZER(symhead);
static struct ldpd_conf         *conf;
static int                       errors;

static int                       af;
static struct ldpd_af_conf      *af_conf;
static struct iface             *iface;
static struct iface_af          *ia;
static struct tnbr              *tnbr;
static struct nbr_params        *nbrp;
static struct l2vpn             *l2vpn;
static struct l2vpn_pw          *pw;

static struct config_defaults    globaldefs;
static struct config_defaults    afdefs;
static struct config_defaults    ifacedefs;
static struct config_defaults    tnbrdefs;
static struct config_defaults    pwdefs;
static struct config_defaults   *defs;

%}

%token  INTERFACE TNEIGHBOR ROUTERID FIBUPDATE RDOMAIN EXPNULL
%token  LHELLOHOLDTIME LHELLOINTERVAL
%token  THELLOHOLDTIME THELLOINTERVAL
%token  THELLOACCEPT AF IPV4 IPV6 INET INET6 GTSMENABLE GTSMHOPS
%token  KEEPALIVE TRANSADDRESS TRANSPREFERENCE DSCISCOINTEROP
%token  NEIGHBOR
%token  TCP MD5SIG PASSWORD KEY
%token  L2VPN TYPE VPLS PWTYPE MTU BRIDGE
%token  ETHERNET ETHERNETTAGGED STATUSTLV CONTROLWORD
%token  PSEUDOWIRE NEIGHBORID NEIGHBORADDR PWID
%token  EXTTAG
%token  YES NO
%token  INCLUDE
%token  ERROR
%token  <v.string>      STRING
%token  <v.number>      NUMBER
%type   <v.number>      yesno ldp_af l2vpn_type pw_type
%type   <v.string>      string
%type   <v.routerid>    routerid
%type   <v.auth>        auth tcpmd5 optnbrprefix

%%

grammar         : /* empty */
                | grammar include '\n'
                | grammar '\n'
                | grammar conf_main '\n'
                | grammar varset '\n'
                | grammar af '\n'
                | grammar neighbor '\n'
                | grammar l2vpn '\n'
                | grammar error '\n'            { file->errors++; }
                ;

include         : INCLUDE STRING                {
                        struct file     *nfile;

                        if ((nfile = pushfile($2,
                            !(global.cmd_opts & LDPD_OPT_NOACTION))) == NULL) {
                                yyerror("failed to include file %s", $2);
                                free($2);
                                YYERROR;
                        }
                        free($2);

                        file = nfile;
                        lungetc('\n');
                }
                ;

string          : string STRING {
                        if (asprintf(&$$, "%s %s", $1, $2) == -1) {
                                free($1);
                                free($2);
                                yyerror("string: asprintf");
                                YYERROR;
                        }
                        free($1);
                        free($2);
                }
                | STRING
                ;

routerid        : STRING {
                        if (inet_pton(AF_INET, $1, &$$) != 1) {
                                yyerror("%s: error parsing router id", $1);
                                free($1);
                                YYERROR;
                        }
                        if (bad_addr_v4($$)) {
                                yyerror("%s: invalid router id", $1);
                                free($1);
                                YYERROR;
                        }
                        free($1);

                        break;
                }
                ;

yesno           : YES   { $$ = 1; }
                | NO    { $$ = 0; }
                ;

ldp_af          : IPV4  { $$ = AF_INET; }
                | IPV6  { $$ = AF_INET6; }
                ;

l2vpn_type      : VPLS  { $$ = L2VPN_TYPE_VPLS; }
                ;

pw_type         : ETHERNET              { $$ = PW_TYPE_ETHERNET; }
                | ETHERNETTAGGED        { $$ = PW_TYPE_ETHERNET_TAGGED; }
                ;

varset          : STRING '=' string {
                        char *s = $1;
                        if (global.cmd_opts & LDPD_OPT_VERBOSE)
                                printf("%s = \"%s\"\n", $1, $3);
                        while (*s++) {
                                if (isspace((unsigned char)*s)) {
                                        yyerror("macro name cannot contain "
                                            "whitespace");
                                        free($1);
                                        free($3);
                                        YYERROR;
                                }
                        }
                        if (symset($1, $3, 0) == -1)
                                fatal("cannot store variable");
                        free($1);
                        free($3);
                }
                ;

conf_main       : ROUTERID routerid {
                        conf->rtr_id = $2;
                }
                | FIBUPDATE yesno {
                        if ($2 == 0)
                                conf->flags |= F_LDPD_NO_FIB_UPDATE;
                        else
                                conf->flags &= ~F_LDPD_NO_FIB_UPDATE;
                }
                | RDOMAIN NUMBER {
                        if ($2 < 0 || $2 > RT_TABLEID_MAX) {
                                yyerror("invalid rdomain");
                                YYERROR;
                        }
                        conf->rdomain = $2;
                }
                | TRANSPREFERENCE ldp_af {
                        conf->trans_pref = $2;

                        switch (conf->trans_pref) {
                        case AF_INET:
                                conf->trans_pref = DUAL_STACK_LDPOV4;
                                break;
                        case AF_INET6:
                                conf->trans_pref = DUAL_STACK_LDPOV6;
                                break;
                        default:
                                yyerror("invalid address-family");
                                YYERROR;
                        }
                }
                | DSCISCOINTEROP yesno {
                        if ($2 == 1)
                                conf->flags |= F_LDPD_DS_CISCO_INTEROP;
                        else
                                conf->flags &= ~F_LDPD_DS_CISCO_INTEROP;
                }
                | auth {
                        LIST_INSERT_HEAD(&conf->auth_list, $1, entry);
                }
                | af_defaults
                | iface_defaults
                | tnbr_defaults
                ;

af              : AF ldp_af {
                        af = $2;
                        switch (af) {
                        case AF_INET:
                                af_conf = &conf->ipv4;
                                break;
                        case AF_INET6:
                                af_conf = &conf->ipv6;
                                break;
                        default:
                                yyerror("invalid address-family");
                                YYERROR;
                        }

                        afdefs = *defs;
                        defs = &afdefs;
                } af_block {
                        af_conf->keepalive = defs->keepalive;
                        af_conf->thello_holdtime = defs->thello_holdtime;
                        af_conf->thello_interval = defs->thello_interval;
                        af_conf->flags = defs->afflags;
                        af_conf->flags |= F_LDPD_AF_ENABLED;
                        af_conf = NULL;
                        af = AF_UNSPEC;
                        defs = &globaldefs;
                }
                ;

af_block        : '{' optnl afopts_l '}'
                | '{' optnl '}'
                |
                ;

afopts_l        : afopts_l afoptsl nl
                | afoptsl optnl
                ;

afoptsl         :  TRANSADDRESS STRING {
                        if (get_address($2, &af_conf->trans_addr) == -1) {
                                yyerror("error parsing transport-address");
                                free($2);
                                YYERROR;
                        }
                        free($2);
                        if (bad_addr(af, &af_conf->trans_addr)) {
                                yyerror("invalid transport-address");
                                YYERROR;
                        }
                        if (af == AF_INET6 &&
                           IN6_IS_SCOPE_EMBED(&af_conf->trans_addr.v6)) {
                                yyerror("ipv6 transport-address can not be "
                                    "link-local");
                                YYERROR;
                        }
                }
                | GTSMENABLE yesno {
                        if ($2 == 0)
                                defs->afflags |= F_LDPD_AF_NO_GTSM;
                }
                | af_defaults
                | iface_defaults
                | tnbr_defaults
                | interface
                | tneighbor
                ;

af_defaults     : THELLOACCEPT yesno {
                        if ($2 == 0)
                                defs->afflags &= ~F_LDPD_AF_THELLO_ACCEPT;
                        else
                                defs->afflags |= F_LDPD_AF_THELLO_ACCEPT;
                }
                | EXPNULL yesno {
                        if ($2 == 0)
                                defs->afflags &= ~F_LDPD_AF_EXPNULL;
                        else
                                defs->afflags |= F_LDPD_AF_EXPNULL;
                }
                | KEEPALIVE NUMBER {
                        if ($2 < MIN_KEEPALIVE || $2 > MAX_KEEPALIVE) {
                                yyerror("keepalive out of range (%d-%d)",
                                    MIN_KEEPALIVE, MAX_KEEPALIVE);
                                YYERROR;
                        }
                        defs->keepalive = $2;
                }
                ;

iface_defaults  : LHELLOHOLDTIME NUMBER {
                        if ($2 < MIN_HOLDTIME || $2 > MAX_HOLDTIME) {
                                yyerror("hello-holdtime out of range (%d-%d)",
                                    MIN_HOLDTIME, MAX_HOLDTIME);
                                YYERROR;
                        }
                        defs->lhello_holdtime = $2;
                }
                | LHELLOINTERVAL NUMBER {
                        if ($2 < MIN_HELLO_INTERVAL ||
                            $2 > MAX_HELLO_INTERVAL) {
                                yyerror("hello-interval out of range (%d-%d)",
                                    MIN_HELLO_INTERVAL, MAX_HELLO_INTERVAL);
                                YYERROR;
                        }
                        defs->lhello_interval = $2;
                }
                ;

tnbr_defaults   : THELLOHOLDTIME NUMBER {
                        if ($2 < MIN_HOLDTIME || $2 > MAX_HOLDTIME) {
                                yyerror("hello-holdtime out of range (%d-%d)",
                                    MIN_HOLDTIME, MAX_HOLDTIME);
                                YYERROR;
                        }
                        defs->thello_holdtime = $2;
                }
                | THELLOINTERVAL NUMBER {
                        if ($2 < MIN_HELLO_INTERVAL ||
                            $2 > MAX_HELLO_INTERVAL) {
                                yyerror("hello-interval out of range (%d-%d)",
                                    MIN_HELLO_INTERVAL, MAX_HELLO_INTERVAL);
                                YYERROR;
                        }
                        defs->thello_interval = $2;
                }
                ;

tcpmd5          : TCP MD5SIG PASSWORD STRING {
                        size_t len;

                        $$ = calloc(1, sizeof(*$$));
                        if ($$ == NULL) {
                                free($4);
                                yyerror("unable to allocate md5 key");
                                YYERROR;
                        }

                        len = strlen($4);
                        if (len > sizeof($$->md5key)) {
                                free($$);
                                free($4);
                                yyerror("tcp md5sig password too long: "
                                    "max %zu", sizeof($$->md5key));
                                YYERROR;
                        }

                        memcpy($$->md5key, $4, len);
                        $$->md5key_len = len;

                        free($4);
                }
                | TCP MD5SIG KEY STRING {
                        int len;

                        $$ = calloc(1, sizeof(*$$));
                        if ($$ == NULL) {
                                free($4);
                                yyerror("unable to allocate md5 key");
                                YYERROR;
                        }

                        len = str2key($$->md5key, $4, sizeof($$->md5key));
                        if (len == -1) {
                                free($$);
                                free($4);
                                yyerror("invalid hex string");
                                YYERROR;
                        }
                        if ((size_t)len > sizeof($$->md5key_len)) {
                                free($$);
                                free($4);
                                yyerror("tcp md5sig key too long: %d "
                                    "max %zu", len, sizeof($$->md5key));
                                YYERROR;
                        }

                        $$->md5key_len = len;

                        free($4);
                }
                | NO TCP MD5SIG {
                        $$ = calloc(1, sizeof(*$$));
                        if ($$ == NULL) {
                                yyerror("unable to allocate no md5 key");
                                YYERROR;
                        }
                        $$->md5key_len = 0;
                }
                ;

optnbrprefix    : STRING {
                        $$ = calloc(1, sizeof(*$$));
                        if ($$ == NULL) {
                                yyerror("unable to allocate auth");
                                free($1);
                                YYERROR;
                        }

                        $$->idlen = inet_net_pton(AF_INET, $1,
                            &$$->id, sizeof($$->id));
                        if ($$->idlen == -1) {
                                yyerror("%s: %s", $1, strerror(errno));
                                free($1);
                                YYERROR;
                        }
                }
                | /* empty */ {
                        $$ = NULL;
                }
                ;

auth            : tcpmd5 optnbrprefix {
                        $$ = $1;
                        if ($2 != NULL) {
                                $$->id = $2->id;
                                $$->idlen = $2->idlen;
                                free($2);
                        } else {
                                $$->id.s_addr = 0;
                                $$->idlen = 0;
                        }
                }
                ;

nbr_opts        : KEEPALIVE NUMBER {
                        if ($2 < MIN_KEEPALIVE || $2 > MAX_KEEPALIVE) {
                                yyerror("keepalive out of range (%d-%d)",
                                    MIN_KEEPALIVE, MAX_KEEPALIVE);
                                YYERROR;
                        }
                        nbrp->keepalive = $2;
                        nbrp->flags |= F_NBRP_KEEPALIVE;
                }
                | tcpmd5 {
                        /* this is syntactic sugar... */
                        $1->id = nbrp->lsr_id;
                        $1->idlen = 32;
                        LIST_INSERT_HEAD(&conf->auth_list, $1, entry);
                }
                | GTSMENABLE yesno {
                        nbrp->flags |= F_NBRP_GTSM;
                        nbrp->gtsm_enabled = $2;
                }
                | GTSMHOPS NUMBER {
                        if ($2 < 1 || $2 > 255) {
                                yyerror("invalid number of hops %lld", $2);
                                YYERROR;
                        }
                        nbrp->gtsm_hops = $2;
                        nbrp->flags |= F_NBRP_GTSM_HOPS;
                }
                ;

pw_defaults     : STATUSTLV yesno {
                        if ($2 == 1)
                                defs->pwflags |= F_PW_STATUSTLV_CONF;
                        else
                                defs->pwflags &= ~F_PW_STATUSTLV_CONF;
                }
                | CONTROLWORD yesno {
                        if ($2 == 1)
                                defs->pwflags |= F_PW_CWORD_CONF;
                        else
                                defs->pwflags &= ~F_PW_CWORD_CONF;
                }
                ;

pwopts          : PWID NUMBER {
                        if ($2 < MIN_PWID_ID ||
                            $2 > MAX_PWID_ID) {
                                yyerror("pw-id out of range (%d-%d)",
                                    MIN_PWID_ID, MAX_PWID_ID);
                                YYERROR;
                        }

                        pw->pwid = $2;
                }
                | NEIGHBORID routerid {
                        pw->lsr_id = $2;
                }
                | NEIGHBORADDR STRING {
                        int              family;
                        union ldpd_addr  addr;

                        if (get_af_address($2, &family, &addr) == -1) {
                                yyerror("error parsing neighbor address");
                                free($2);
                                YYERROR;
                        }
                        free($2);
                        if (bad_addr(family, &addr)) {
                                yyerror("invalid neighbor address");
                                YYERROR;
                        }
                        if (family == AF_INET6 &&
                            IN6_IS_SCOPE_EMBED(&addr.v6)) {
                                yyerror("neighbor address can not be "
                                    "link-local");
                                YYERROR;
                        }

                        pw->af = family;
                        pw->addr = addr;
                }
                | pw_defaults
                ;

pseudowire      : PSEUDOWIRE STRING {
                        struct kif      *kif;

                        if ((kif = kif_findname($2)) == NULL) {
                                yyerror("unknown interface %s", $2);
                                free($2);
                                YYERROR;
                        }
                        free($2);

                        if (kif->if_type != IFT_MPLSTUNNEL &&
                            kmpw_find(kif->ifname) == -1) {
                                yyerror("unsupported interface type on "
                                    "interface %s", kif->ifname);
                                YYERROR;
                        }

                        pw = conf_get_l2vpn_pw(l2vpn, kif);
                        if (pw == NULL)
                                YYERROR;

                        pwdefs = *defs;
                        defs = &pwdefs;
                } pw_block {
                        struct l2vpn    *l;
                        struct l2vpn_pw *p;

                        /* check for errors */
                        if (pw->pwid == 0) {
                                yyerror("missing pseudowire id");
                                YYERROR;
                        }
                        if (pw->lsr_id.s_addr == INADDR_ANY) {
                                yyerror("missing pseudowire neighbor-id");
                                YYERROR;
                        }
                        LIST_FOREACH(l, &conf->l2vpn_list, entry) {
                                LIST_FOREACH(p, &l->pw_list, entry) {
                                        if (pw != p &&
                                            pw->pwid == p->pwid &&
                                            pw->af == p->af &&
                                            pw->lsr_id.s_addr ==
                                            p->lsr_id.s_addr) {
                                                yyerror("pseudowire already "
                                                    "configured");
                                                YYERROR;
                                        }
                                }
                        }

                        /*
                         * If the neighbor address is not specified, use the
                         * neighbor id.
                         */
                        if (pw->af == AF_UNSPEC) {
                                pw->af = AF_INET;
                                pw->addr.v4 = pw->lsr_id;
                        }

                        pw->flags = defs->pwflags;
                        pw = NULL;
                        defs = &globaldefs;
                }
                ;

pw_block        : '{' optnl pwopts_l '}'
                | '{' optnl '}'
                | /* nothing */
                ;

pwopts_l        : pwopts_l pwopts nl
                | pwopts optnl
                ;

l2vpnopts       : PWTYPE pw_type {
                        l2vpn->pw_type = $2;
                }
                | MTU NUMBER {
                        if ($2 < MIN_L2VPN_MTU ||
                            $2 > MAX_L2VPN_MTU) {
                                yyerror("l2vpn mtu out of range (%d-%d)",
                                    MIN_L2VPN_MTU, MAX_L2VPN_MTU);
                                YYERROR;
                        }
                        l2vpn->mtu = $2;
                }
                | pw_defaults
                | BRIDGE STRING {
                        struct l2vpn     *l;
                        struct kif       *kif;

                        if ((kif = kif_findname($2)) == NULL) {
                                yyerror("unknown interface %s", $2);
                                free($2);
                                YYERROR;
                        }
                        free($2);

                        if (l2vpn->br_ifindex != 0) {
                                yyerror("bridge interface cannot be "
                                    "redefined on l2vpn %s", l2vpn->name);
                                YYERROR;
                        }

                        if (kif->if_type != IFT_BRIDGE) {
                                yyerror("unsupported interface type on "
                                    "interface %s", kif->ifname);
                                YYERROR;
                        }

                        LIST_FOREACH(l, &conf->l2vpn_list, entry) {
                                if (l->br_ifindex == kif->ifindex) {
                                        yyerror("bridge %s is already being "
                                            "used by l2vpn %s", kif->ifname,
                                            l->name);
                                        YYERROR;
                                }
                        }

                        l2vpn->br_ifindex = kif->ifindex;
                        strlcpy(l2vpn->br_ifname, kif->ifname,
                            sizeof(l2vpn->br_ifname));
                }
                | INTERFACE STRING {
                        struct kif      *kif;
                        struct l2vpn_if *lif;

                        if ((kif = kif_findname($2)) == NULL) {
                                yyerror("unknown interface %s", $2);
                                free($2);
                                YYERROR;
                        }
                        free($2);

                        lif = conf_get_l2vpn_if(l2vpn, kif);
                        if (lif == NULL)
                                YYERROR;
                }
                | pseudowire
                ;

optnl           : '\n' optnl
                |
                ;

nl              : '\n' optnl            /* one newline or more */
                ;

interface       : INTERFACE STRING      {
                        struct kif      *kif;

                        if ((kif = kif_findname($2)) == NULL) {
                                yyerror("unknown interface %s", $2);
                                free($2);
                                YYERROR;
                        }
                        free($2);

                        iface = conf_get_if(kif);
                        if (iface == NULL)
                                YYERROR;

                        ia = iface_af_get(iface, af);
                        if (ia->enabled) {
                                yyerror("interface %s already configured for "
                                    "address-family %s", kif->ifname,
                                    af_name(af));
                                YYERROR;
                        }
                        ia->enabled = 1;

                        ifacedefs = *defs;
                        defs = &ifacedefs;
                } interface_block {
                        ia->hello_holdtime = defs->lhello_holdtime;
                        ia->hello_interval = defs->lhello_interval;
                        iface = NULL;
                        defs = &afdefs;
                }
                ;

interface_block : '{' optnl interfaceopts_l '}'
                | '{' optnl '}'
                | /* nothing */
                ;

interfaceopts_l : interfaceopts_l iface_defaults nl
                | iface_defaults optnl
                ;

tneighbor       : TNEIGHBOR STRING      {
                        union ldpd_addr  addr;

                        if (get_address($2, &addr) == -1) {
                                yyerror("error parsing targeted-neighbor "
                                    "address");
                                free($2);
                                YYERROR;
                        }
                        free($2);
                        if (bad_addr(af, &addr)) {
                                yyerror("invalid targeted-neighbor address");
                                YYERROR;
                        }
                        if (af == AF_INET6 &&
                           IN6_IS_SCOPE_EMBED(&addr.v6)) {
                                yyerror("targeted-neighbor address can not be "
                                    "link-local");
                                YYERROR;
                        }

                        tnbr = conf_get_tnbr(&addr);
                        if (tnbr == NULL)
                                YYERROR;

                        tnbrdefs = *defs;
                        defs = &tnbrdefs;
                } tneighbor_block {
                        tnbr->hello_holdtime = defs->thello_holdtime;
                        tnbr->hello_interval = defs->thello_interval;
                        tnbr = NULL;
                        defs = &afdefs;
                }
                ;

tneighbor_block : '{' optnl tneighboropts_l '}'
                | '{' optnl '}'
                | /* nothing */
                ;

tneighboropts_l : tneighboropts_l tnbr_defaults nl
                | tnbr_defaults optnl
                ;

neighbor        : NEIGHBOR routerid     {
                        nbrp = conf_get_nbrp($2);
                        if (nbrp == NULL)
                                YYERROR;
                } neighbor_block {
                        nbrp = NULL;
                }
                ;

neighbor_block  : '{' optnl neighboropts_l '}'
                | '{' optnl '}'
                | /* nothing */
                ;

neighboropts_l  : neighboropts_l nbr_opts nl
                | nbr_opts optnl
                ;

l2vpn           : L2VPN STRING TYPE l2vpn_type {
                        l2vpn = conf_get_l2vpn($2);
                        if (l2vpn == NULL)
                                YYERROR;
                        l2vpn->type = $4;
                } l2vpn_block {
                        l2vpn = NULL;
                }
                ;

l2vpn_block     : '{' optnl l2vpnopts_l '}'
                | '{' optnl '}'
                | /* nothing */
                ;

l2vpnopts_l     : l2vpnopts_l l2vpnopts nl
                | l2vpnopts optnl
                ;

%%

struct keywords {
        const char      *k_name;
        int              k_val;
};

static int
yyerror(const char *fmt, ...)
{
        va_list          ap;
        char            *msg;

        file->errors++;
        va_start(ap, fmt);
        if (vasprintf(&msg, fmt, ap) == -1)
                fatalx("yyerror vasprintf");
        va_end(ap);
        logit(LOG_CRIT, "%s:%d: %s", file->name, yylval.lineno, msg);
        free(msg);
        return (0);
}

static int
kw_cmp(const void *k, const void *e)
{
        return (strcmp(k, ((const struct keywords *)e)->k_name));
}

static int
lookup(char *s)
{
        /* this has to be sorted always */
        static const struct keywords keywords[] = {
                {"address-family",              AF},
                {"bridge",                      BRIDGE},
                {"control-word",                CONTROLWORD},
                {"ds-cisco-interop",            DSCISCOINTEROP},
                {"ethernet",                    ETHERNET},
                {"ethernet-tagged",             ETHERNETTAGGED},
                {"explicit-null",               EXPNULL},
                {"fib-update",                  FIBUPDATE},
                {"gtsm-enable",                 GTSMENABLE},
                {"gtsm-hops",                   GTSMHOPS},
                {"include",                     INCLUDE},
                {"inet",                        INET},
                {"inet6",                       INET6},
                {"interface",                   INTERFACE},
                {"ipv4",                        IPV4},
                {"ipv6",                        IPV6},
                {"keepalive",                   KEEPALIVE},
                {"key",                         KEY},
                {"l2vpn",                       L2VPN},
                {"link-hello-holdtime",         LHELLOHOLDTIME},
                {"link-hello-interval",         LHELLOINTERVAL},
                {"md5sig",                      MD5SIG},
                {"mtu",                         MTU},
                {"neighbor",                    NEIGHBOR},
                {"neighbor-addr",               NEIGHBORADDR},
                {"neighbor-id",                 NEIGHBORID},
                {"no",                          NO},
                {"password",                    PASSWORD},
                {"pseudowire",                  PSEUDOWIRE},
                {"pw-id",                       PWID},
                {"pw-type",                     PWTYPE},
                {"rdomain",                     RDOMAIN},
                {"router-id",                   ROUTERID},
                {"status-tlv",                  STATUSTLV},
                {"targeted-hello-accept",       THELLOACCEPT},
                {"targeted-hello-holdtime",     THELLOHOLDTIME},
                {"targeted-hello-interval",     THELLOINTERVAL},
                {"targeted-neighbor",           TNEIGHBOR},
                {"tcp",                         TCP},
                {"transport-address",           TRANSADDRESS},
                {"transport-preference",        TRANSPREFERENCE},
                {"type",                        TYPE},
                {"vpls",                        VPLS},
                {"yes",                         YES}
        };
        const struct keywords   *p;

        p = bsearch(s, keywords, sizeof(keywords)/sizeof(keywords[0]),
            sizeof(keywords[0]), kw_cmp);

        if (p)
                return (p->k_val);
        else
                return (STRING);
}

#define START_EXPAND    1
#define DONE_EXPAND     2

static int      expanding;

int
igetc(void)
{
        int     c;

        while (1) {
                if (file->ungetpos > 0)
                        c = file->ungetbuf[--file->ungetpos];
                else
                        c = getc(file->stream);

                if (c == START_EXPAND)
                        expanding = 1;
                else if (c == DONE_EXPAND)
                        expanding = 0;
                else
                        break;
        }
        return (c);
}

static int
lgetc(int quotec)
{
        int             c, next;

        if (quotec) {
                if ((c = igetc()) == EOF) {
                        yyerror("reached end of file while parsing "
                            "quoted string");
                        if (file == topfile || popfile() == EOF)
                                return (EOF);
                        return (quotec);
                }
                return (c);
        }

        while ((c = igetc()) == '\\') {
                next = igetc();
                if (next != '\n') {
                        c = next;
                        break;
                }
                yylval.lineno = file->lineno;
                file->lineno++;
        }

        if (c == EOF) {
                /*
                 * Fake EOL when hit EOF for the first time. This gets line
                 * count right if last line in included file is syntactically
                 * invalid and has no newline.
                 */
                if (file->eof_reached == 0) {
                        file->eof_reached = 1;
                        return ('\n');
                }
                while (c == EOF) {
                        if (file == topfile || popfile() == EOF)
                                return (EOF);
                        c = igetc();
                }
        }
        return (c);
}

void
lungetc(int c)
{
        if (c == EOF)
                return;

        if (file->ungetpos >= file->ungetsize) {
                void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
                if (p == NULL)
                        err(1, "%s", __func__);
                file->ungetbuf = p;
                file->ungetsize *= 2;
        }
        file->ungetbuf[file->ungetpos++] = c;
}

static int
findeol(void)
{
        int     c;

        /* skip to either EOF or the first real EOL */
        while (1) {
                c = lgetc(0);
                if (c == '\n') {
                        file->lineno++;
                        break;
                }
                if (c == EOF)
                        break;
        }
        return (ERROR);
}

static int
yylex(void)
{
        char     buf[8096];
        char    *p, *val;
        int      quotec, next, c;
        int      token;

 top:
        p = buf;
        while ((c = lgetc(0)) == ' ' || c == '\t')
                ; /* nothing */

        yylval.lineno = file->lineno;
        if (c == '#')
                while ((c = lgetc(0)) != '\n' && c != EOF)
                        ; /* nothing */
        if (c == '$' && !expanding) {
                while (1) {
                        if ((c = lgetc(0)) == EOF)
                                return (0);

                        if (p + 1 >= buf + sizeof(buf) - 1) {
                                yyerror("string too long");
                                return (findeol());
                        }
                        if (isalnum(c) || c == '_') {
                                *p++ = c;
                                continue;
                        }
                        *p = '\0';
                        lungetc(c);
                        break;
                }
                val = symget(buf);
                if (val == NULL) {
                        yyerror("macro '%s' not defined", buf);
                        return (findeol());
                }
                p = val + strlen(val) - 1;
                lungetc(DONE_EXPAND);
                while (p >= val) {
                        lungetc((unsigned char)*p);
                        p--;
                }
                lungetc(START_EXPAND);
                goto top;
        }

        switch (c) {
        case '\'':
        case '"':
                quotec = c;
                while (1) {
                        if ((c = lgetc(quotec)) == EOF)
                                return (0);
                        if (c == '\n') {
                                file->lineno++;
                                continue;
                        } else if (c == '\\') {
                                if ((next = lgetc(quotec)) == EOF)
                                        return (0);
                                if (next == quotec || next == ' ' ||
                                    next == '\t')
                                        c = next;
                                else if (next == '\n') {
                                        file->lineno++;
                                        continue;
                                } else
                                        lungetc(next);
                        } else if (c == quotec) {
                                *p = '\0';
                                break;
                        } else if (c == '\0') {
                                yyerror("syntax error");
                                return (findeol());
                        }
                        if (p + 1 >= buf + sizeof(buf) - 1) {
                                yyerror("string too long");
                                return (findeol());
                        }
                        *p++ = c;
                }
                yylval.v.string = strdup(buf);
                if (yylval.v.string == NULL)
                        err(1, "%s", __func__);
                return (STRING);
        }

#define allowed_to_end_number(x) \
        (isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')

        if (c == '-' || isdigit(c)) {
                do {
                        *p++ = c;
                        if ((size_t)(p-buf) >= sizeof(buf)) {
                                yyerror("string too long");
                                return (findeol());
                        }
                } while ((c = lgetc(0)) != EOF && isdigit(c));
                lungetc(c);
                if (p == buf + 1 && buf[0] == '-')
                        goto nodigits;
                if (c == EOF || allowed_to_end_number(c)) {
                        const char *errstr = NULL;

                        *p = '\0';
                        yylval.v.number = strtonum(buf, LLONG_MIN,
                            LLONG_MAX, &errstr);
                        if (errstr) {
                                yyerror("\"%s\" invalid number: %s",
                                    buf, errstr);
                                return (findeol());
                        }
                        return (NUMBER);
                } else {
 nodigits:
                        while (p > buf + 1)
                                lungetc((unsigned char)*--p);
                        c = (unsigned char)*--p;
                        if (c == '-')
                                return (c);
                }
        }

#define allowed_in_string(x) \
        (isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
        x != '{' && x != '}' && \
        x != '!' && x != '=' && x != '#' && \
        x != ','))

        if (isalnum(c) || c == ':' || c == '_') {
                do {
                        *p++ = c;
                        if ((size_t)(p-buf) >= sizeof(buf)) {
                                yyerror("string too long");
                                return (findeol());
                        }
                } while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
                lungetc(c);
                *p = '\0';
                if ((token = lookup(buf)) == STRING)
                        if ((yylval.v.string = strdup(buf)) == NULL)
                                err(1, "%s", __func__);
                return (token);
        }
        if (c == '\n') {
                yylval.lineno = file->lineno;
                file->lineno++;
        }
        if (c == EOF)
                return (0);
        return (c);
}

static int
check_file_secrecy(int fd, const char *fname)
{
        struct stat     st;

        if (fstat(fd, &st)) {
                log_warn("cannot stat %s", fname);
                return (-1);
        }
        if (st.st_uid != 0 && st.st_uid != getuid()) {
                log_warnx("%s: owner not root or current user", fname);
                return (-1);
        }
        if (st.st_mode & (S_IWGRP | S_IXGRP | S_IRWXO)) {
                log_warnx("%s: group writable or world read/writable", fname);
                return (-1);
        }
        return (0);
}

static struct file *
pushfile(const char *name, int secret)
{
        struct file     *nfile;

        if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
                log_warn("%s", __func__);
                return (NULL);
        }
        if ((nfile->name = strdup(name)) == NULL) {
                log_warn("%s", __func__);
                free(nfile);
                return (NULL);
        }
        if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
                log_warn("%s: %s", __func__, nfile->name);
                free(nfile->name);
                free(nfile);
                return (NULL);
        } else if (secret &&
            check_file_secrecy(fileno(nfile->stream), nfile->name)) {
                fclose(nfile->stream);
                free(nfile->name);
                free(nfile);
                return (NULL);
        }
        nfile->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
        nfile->ungetsize = 16;
        nfile->ungetbuf = malloc(nfile->ungetsize);
        if (nfile->ungetbuf == NULL) {
                log_warn("%s", __func__);
                fclose(nfile->stream);
                free(nfile->name);
                free(nfile);
                return (NULL);
        }
        TAILQ_INSERT_TAIL(&files, nfile, entry);
        return (nfile);
}

static int
popfile(void)
{
        struct file     *prev;

        if ((prev = TAILQ_PREV(file, files, entry)) != NULL)
                prev->errors += file->errors;

        TAILQ_REMOVE(&files, file, entry);
        fclose(file->stream);
        free(file->name);
        free(file->ungetbuf);
        free(file);
        file = prev;
        return (file ? 0 : EOF);
}

struct ldpd_conf *
parse_config(char *filename)
{
        struct sym      *sym, *next;

        conf = config_new_empty();
        conf->rdomain = 0;
        conf->trans_pref = DUAL_STACK_LDPOV6;

        defs = &globaldefs;
        defs->keepalive = DEFAULT_KEEPALIVE;
        defs->lhello_holdtime = LINK_DFLT_HOLDTIME;
        defs->lhello_interval = DEFAULT_HELLO_INTERVAL;
        defs->thello_holdtime = TARGETED_DFLT_HOLDTIME;
        defs->thello_interval = DEFAULT_HELLO_INTERVAL;
        defs->pwflags = F_PW_STATUSTLV_CONF|F_PW_CWORD_CONF;

        if ((file = pushfile(filename,
            !(global.cmd_opts & LDPD_OPT_NOACTION))) == NULL) {
                free(conf);
                return (NULL);
        }
        topfile = file;

        yyparse();
        errors = file->errors;
        popfile();

        /* Free macros and check which have not been used. */
        TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
                if ((global.cmd_opts & LDPD_OPT_VERBOSE2) && !sym->used)
                        fprintf(stderr, "warning: macro '%s' not "
                            "used\n", sym->nam);
                if (!sym->persist) {
                        free(sym->nam);
                        free(sym->val);
                        TAILQ_REMOVE(&symhead, sym, entry);
                        free(sym);
                }
        }

        /* check that all interfaces belong to the configured rdomain */
        errors += conf_check_rdomain(conf->rdomain);

        /* free global config defaults */
        if (errors) {
                clear_config(conf);
                return (NULL);
        }

        if (conf->rtr_id.s_addr == INADDR_ANY)
                conf->rtr_id.s_addr = get_rtr_id();

        /* if the ipv4 transport-address is not set, use the router-id */
        if ((conf->ipv4.flags & F_LDPD_AF_ENABLED) &&
            conf->ipv4.trans_addr.v4.s_addr == INADDR_ANY)
                conf->ipv4.trans_addr.v4 = conf->rtr_id;

        return (conf);
}

static int
symset(const char *nam, const char *val, int persist)
{
        struct sym      *sym;

        TAILQ_FOREACH(sym, &symhead, entry) {
                if (strcmp(nam, sym->nam) == 0)
                        break;
        }

        if (sym != NULL) {
                if (sym->persist == 1)
                        return (0);
                else {
                        free(sym->nam);
                        free(sym->val);
                        TAILQ_REMOVE(&symhead, sym, entry);
                        free(sym);
                }
        }
        if ((sym = calloc(1, sizeof(*sym))) == NULL)
                return (-1);

        sym->nam = strdup(nam);
        if (sym->nam == NULL) {
                free(sym);
                return (-1);
        }
        sym->val = strdup(val);
        if (sym->val == NULL) {
                free(sym->nam);
                free(sym);
                return (-1);
        }
        sym->used = 0;
        sym->persist = persist;
        TAILQ_INSERT_TAIL(&symhead, sym, entry);
        return (0);
}

int
cmdline_symset(char *s)
{
        char    *sym, *val;
        int     ret;

        if ((val = strrchr(s, '=')) == NULL)
                return (-1);
        sym = strndup(s, val - s);
        if (sym == NULL)
                errx(1, "%s: strndup", __func__);
        ret = symset(sym, val + 1, 1);
        free(sym);

        return (ret);
}

static char *
symget(const char *nam)
{
        struct sym      *sym;

        TAILQ_FOREACH(sym, &symhead, entry) {
                if (strcmp(nam, sym->nam) == 0) {
                        sym->used = 1;
                        return (sym->val);
                }
        }
        return (NULL);
}

static struct iface *
conf_get_if(struct kif *kif)
{
        struct iface    *i;
        struct l2vpn    *l;

        if (kif->if_type == IFT_LOOP ||
            kif->if_type == IFT_CARP ||
            kif->if_type == IFT_BRIDGE ||
            kif->if_type == IFT_MPLSTUNNEL) {
                yyerror("unsupported interface type on interface %s",
                    kif->ifname);
                return (NULL);
        }

        LIST_FOREACH(l, &conf->l2vpn_list, entry)
                if (l2vpn_if_find(l, kif->ifindex)) {
                        yyerror("interface %s already configured under "
                            "l2vpn %s", kif->ifname, l->name);
                        return (NULL);
                }

        LIST_FOREACH(i, &conf->iface_list, entry)
                if (i->ifindex == kif->ifindex)
                        return (i);

        i = if_new(kif);
        LIST_INSERT_HEAD(&conf->iface_list, i, entry);
        return (i);
}

static struct tnbr *
conf_get_tnbr(union ldpd_addr *addr)
{
        struct tnbr     *t;

        t = tnbr_find(conf, af, addr);
        if (t) {
                yyerror("targeted neighbor %s already configured",
                    log_addr(af, addr));
                return (NULL);
        }

        t = tnbr_new(conf, af, addr);
        t->flags |= F_TNBR_CONFIGURED;
        LIST_INSERT_HEAD(&conf->tnbr_list, t, entry);
        return (t);
}

static struct nbr_params *
conf_get_nbrp(struct in_addr lsr_id)
{
        struct nbr_params       *n;

        LIST_FOREACH(n, &conf->nbrp_list, entry) {
                if (n->lsr_id.s_addr == lsr_id.s_addr) {
                        yyerror("neighbor %s already configured",
                            inet_ntoa(lsr_id));
                        return (NULL);
                }
        }

        n = nbr_params_new(lsr_id);
        LIST_INSERT_HEAD(&conf->nbrp_list, n, entry);
        return (n);
}

static struct l2vpn *
conf_get_l2vpn(char *name)
{
        struct l2vpn     *l;

        if (l2vpn_find(conf, name)) {
                yyerror("l2vpn %s already configured", name);
                return (NULL);
        }

        l = l2vpn_new(name);
        LIST_INSERT_HEAD(&conf->l2vpn_list, l, entry);
        return (l);
}

static struct l2vpn_if *
conf_get_l2vpn_if(struct l2vpn *l, struct kif *kif)
{
        struct iface    *i;
        struct l2vpn    *ltmp;
        struct l2vpn_if *f;

        if (kif->if_type == IFT_LOOP ||
            kif->if_type == IFT_CARP ||
            kif->if_type == IFT_BRIDGE ||
            kif->if_type == IFT_MPLSTUNNEL) {
                yyerror("unsupported interface type on interface %s",
                    kif->ifname);
                return (NULL);
        }

        LIST_FOREACH(ltmp, &conf->l2vpn_list, entry)
                if (l2vpn_if_find(ltmp, kif->ifindex)) {
                        yyerror("interface %s already configured under "
                            "l2vpn %s", kif->ifname, ltmp->name);
                        return (NULL);
                }

        LIST_FOREACH(i, &conf->iface_list, entry) {
                if (i->ifindex == kif->ifindex) {
                        yyerror("interface %s already configured",
                            kif->ifname);
                        return (NULL);
                }
        }

        f = l2vpn_if_new(l, kif);
        LIST_INSERT_HEAD(&l2vpn->if_list, f, entry);
        return (f);
}

static struct l2vpn_pw *
conf_get_l2vpn_pw(struct l2vpn *l, struct kif *kif)
{
        struct l2vpn    *ltmp;
        struct l2vpn_pw *p;

        LIST_FOREACH(ltmp, &conf->l2vpn_list, entry) {
                if (l2vpn_pw_find(ltmp, kif->ifindex)) {
                        yyerror("pseudowire %s is already being "
                            "used by l2vpn %s", kif->ifname, ltmp->name);
                        return (NULL);
                }
        }

        p = l2vpn_pw_new(l, kif);
        LIST_INSERT_HEAD(&l2vpn->pw_list, p, entry);
        return (p);
}

int
conf_check_rdomain(unsigned int rdomain)
{
        struct iface    *i;
        int              errs = 0;

        LIST_FOREACH(i, &conf->iface_list, entry) {
                if (i->rdomain != rdomain) {
                        logit(LOG_CRIT, "interface %s not in rdomain %u",
                            i->name, rdomain);
                        errs++;
                }
        }

        return (errs);
}

static void
clear_config(struct ldpd_conf *xconf)
{
        struct iface            *i;
        struct tnbr             *t;
        struct nbr_params       *n;
        struct l2vpn            *l;
        struct l2vpn_if         *f;
        struct l2vpn_pw         *p;

        while ((i = LIST_FIRST(&xconf->iface_list)) != NULL) {
                LIST_REMOVE(i, entry);
                free(i);
        }

        while ((t = LIST_FIRST(&xconf->tnbr_list)) != NULL) {
                LIST_REMOVE(t, entry);
                free(t);
        }

        while ((n = LIST_FIRST(&xconf->nbrp_list)) != NULL) {
                LIST_REMOVE(n, entry);
                free(n);
        }

        while ((l = LIST_FIRST(&xconf->l2vpn_list)) != NULL) {
                while ((f = LIST_FIRST(&l->if_list)) != NULL) {
                        LIST_REMOVE(f, entry);
                        free(f);
                }
                while ((p = LIST_FIRST(&l->pw_list)) != NULL) {
                        LIST_REMOVE(p, entry);
                        free(p);
                }
                LIST_REMOVE(l, entry);
                free(l);
        }

        free(xconf);
}

static uint32_t
get_rtr_id(void)
{
        struct ifaddrs          *ifap, *ifa;
        uint32_t                 ip = 0, cur, localnet;

        localnet = htonl(INADDR_LOOPBACK & IN_CLASSA_NET);

        if (getifaddrs(&ifap) == -1) {
                log_warn("getifaddrs");
                return (0);
        }

        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                if (strncmp(ifa->ifa_name, "carp", 4) == 0)
                        continue;
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                cur = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr.s_addr;
                if ((cur & localnet) == localnet)       /* skip 127/8 */
                        continue;
                if (ntohl(cur) < ntohl(ip) || ip == 0)
                        ip = cur;
        }
        freeifaddrs(ifap);

        return (ip);
}

static int
get_address(const char *s, union ldpd_addr *addr)
{
        switch (af) {
        case AF_INET:
                if (inet_pton(AF_INET, s, &addr->v4) != 1)
                        return (-1);
                break;
        case AF_INET6:
                if (inet_pton(AF_INET6, s, &addr->v6) != 1)
                        return (-1);
                break;
        default:
                return (-1);
        }

        return (0);
}

static int
get_af_address(const char *s, int *family, union ldpd_addr *addr)
{
        if (inet_pton(AF_INET, s, &addr->v4) == 1) {
                *family = AF_INET;
                return (0);
        }

        if (inet_pton(AF_INET6, s, &addr->v6) == 1) {
                *family = AF_INET6;
                return (0);
        }

        return (-1);
}

static int
hexchar(int ch)
{
        if (ch >= '0' && ch <= '9')
                return (ch - '0');
        if (ch >= 'a' && ch <= 'f')
                return (ch - 'a');
        if (ch >= 'A' && ch <= 'F')
                return (ch - 'A');

        return (-1);
}

static int
str2key(char *dst, const char *src, int dstlen)
{
        int             i = 0;
        int             digit;

        while (*src != '\0') {
                digit = hexchar(*src);
                if (digit == -1)
                        return (-1);

                if (i < dstlen)
                        *dst = digit << 4;

                src++;
                if (*src == '\0')
                        return (-1);
                digit = hexchar(*src);
                if (digit == -1)
                        return (-1);

                if (i < dstlen)
                        *dst |= digit;

                src++;
                i++;
        }

        return (i);
}