root/usr.sbin/rad/parse.y
/*      $OpenBSD: parse.y,v 1.23 2024/05/17 06:50:14 florian Exp $      */

/*
 * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
 * Copyright (c) 2004, 2005 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/types.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <netinet/in.h>
#include <netinet/icmp6.h>
#include <net/if.h>

#include <arpa/inet.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <event.h>
#include <imsg.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>

#include "log.h"
#include "rad.h"
#include "frontend.h"

TAILQ_HEAD(files, file)          files = TAILQ_HEAD_INITIALIZER(files);
static 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;
} *file, *topfile;
struct file     *pushfile(const char *, int);
int              popfile(void);
int              check_file_secrecy(int, const char *);
int              yyparse(void);
int              yylex(void);
int              yyerror(const char *, ...)
    __attribute__((__format__ (printf, 1, 2)))
    __attribute__((__nonnull__ (1)));
int              kw_cmp(const void *, const void *);
int              lookup(char *);
int              igetc(void);
int              lgetc(int);
void             lungetc(int);
int              findeol(void);

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

int      symset(const char *, const char *, int);
char    *symget(const char *);

void     clear_config(struct rad_conf *xconf);

static struct rad_conf          *conf;
static struct ra_options_conf   *ra_options;
static int                       errors;

static struct ra_iface_conf     *ra_iface_conf;
static struct ra_prefix_conf    *ra_prefix_conf;
static struct ra_pref64_conf    *ra_pref64_conf;

struct ra_prefix_conf   *conf_get_ra_prefix(struct in6_addr*, int);
struct ra_pref64_conf   *conf_get_ra_pref64(struct in6_addr*, int);
struct ra_iface_conf    *conf_get_ra_iface(char *);
void                     copy_dns_options(const struct ra_options_conf *,
                            struct ra_options_conf *);
void                     copy_pref64_options(const struct ra_options_conf *,
                            struct ra_options_conf *);

typedef struct {
        union {
                int64_t          number;
                char            *string;
        } v;
        int lineno;
} YYSTYPE;

%}

%token  RA_IFACE YES NO INCLUDE ERROR
%token  DEFAULT ROUTER HOP LIMIT MANAGED ADDRESS
%token  CONFIGURATION OTHER LIFETIME REACHABLE TIME RETRANS TIMER
%token  AUTO PREFIX VALID PREFERENCE PREFERRED LIFETIME ONLINK AUTONOMOUS
%token  ADDRESS_CONFIGURATION DNS NAMESERVER SEARCH MTU NAT64 HIGH MEDIUM LOW
%token  SOURCE LINK_LAYER

%token  <v.string>      STRING
%token  <v.number>      NUMBER
%type   <v.number>      yesno
%type   <v.string>      string

%%

grammar         : /* empty */
                | grammar include '\n'
                | grammar '\n'
                | grammar { ra_options = &conf->ra_options; } conf_main '\n'
                | grammar varset '\n'
                | grammar ra_iface '\n'
                | grammar error '\n'            { file->errors++; }
                ;

include         : INCLUDE STRING                {
                        struct file     *nfile;

                        if ((nfile = pushfile($2, 0)) == 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
                ;

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

varset          : STRING '=' string             {
                        char *s = $1;
                        if (cmd_opts & 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       : ra_opt_block {
                        ra_options = &conf->ra_options;
                }
                ;

ra_opt_block    : DEFAULT ROUTER yesno {
                        ra_options->dfr = $3;
                }
                | HOP LIMIT NUMBER {
                        ra_options->cur_hl = $3;
                }
                | MANAGED ADDRESS CONFIGURATION yesno {
                        ra_options->m_flag = $4;
                }
                | OTHER CONFIGURATION yesno {
                        ra_options->o_flag = $3;
                }
                | ROUTER LIFETIME NUMBER {
                        ra_options->router_lifetime = $3;
                }
                | ROUTER PREFERENCE HIGH {
                        ra_options->rtpref = ND_RA_FLAG_RTPREF_HIGH;
                }
                | ROUTER PREFERENCE MEDIUM {
                        ra_options->rtpref = ND_RA_FLAG_RTPREF_MEDIUM;
                }
                | ROUTER PREFERENCE LOW {
                        ra_options->rtpref = ND_RA_FLAG_RTPREF_LOW;
                }
                | REACHABLE TIME NUMBER {
                        ra_options->reachable_time = $3;
                }
                | RETRANS TIMER NUMBER {
                        ra_options->retrans_timer = $3;
                }
                | SOURCE LINK_LAYER ADDRESS yesno {
                        ra_options->source_link_addr = $4;
                }
                | MTU NUMBER {
                        ra_options->mtu = $2;
                }
                | NAT64 PREFIX STRING {
                        struct in6_addr  addr;
                        int              prefixlen;
                        char            *p;
                        const char      *errstr;

                        memset(&addr, 0, sizeof(addr));
                        p = strchr($3, '/');
                        if (p != NULL) {
                                *p++ = '\0';
                                prefixlen = strtonum(p, 0, 128, &errstr);
                                if (errstr != NULL) {
                                        yyerror("error parsing prefix "
                                            "\"%s/%s\"", $3, p);
                                        free($3);
                                        YYERROR;
                                }
                        } else
                                prefixlen = 96;

                        switch (prefixlen) {
                        case 96:
                        case 64:
                        case 56:
                        case 48:
                        case 40:
                        case 32:
                                break;
                        default:
                                yyerror("invalid nat64 prefix length: %d",
                                    prefixlen);
                                YYERROR;
                                break;
                        }
                        if(inet_pton(AF_INET6, $3, &addr) == 0) {
                                yyerror("error parsing prefix \"%s/%d\"", $3,
                                    prefixlen);
                                free($3);
                                YYERROR;
                        }
                        mask_prefix(&addr, prefixlen);
                        ra_pref64_conf = conf_get_ra_pref64(&addr, prefixlen);
                } ra_pref64_block {
                        ra_pref64_conf = NULL;
                }
                | DNS dns_block
                ;

optnl           : '\n' optnl            /* zero or more newlines */
                | /*empty*/
                ;

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

ra_iface        : RA_IFACE STRING {
                        ra_iface_conf = conf_get_ra_iface($2);
                        /* set auto prefix defaults */
                        ra_iface_conf->autoprefix = conf_get_ra_prefix(NULL, 0);
                        ra_options = &ra_iface_conf->ra_options;
                } ra_iface_block {
                        ra_iface_conf = NULL;
                        ra_options = &conf->ra_options;
                }
                ;

ra_iface_block  : '{' optnl ra_ifaceopts_l '}'
                | '{' optnl '}'
                | /* empty */
                ;

ra_ifaceopts_l  : ra_ifaceopts_l ra_ifaceoptsl nl
                | ra_ifaceoptsl optnl
                ;

ra_ifaceoptsl   : NO AUTO PREFIX {
                        free(ra_iface_conf->autoprefix);
                        ra_iface_conf->autoprefix = NULL;
                }
                | AUTO PREFIX {
                        if (ra_iface_conf->autoprefix == NULL)
                                ra_iface_conf->autoprefix =
                                    conf_get_ra_prefix(NULL, 0);
                        ra_prefix_conf = ra_iface_conf->autoprefix;
                } ra_prefix_block {
                        ra_prefix_conf = NULL;
                }
                | PREFIX STRING {
                        struct in6_addr  addr;
                        int              prefixlen;
                        char            *p;
                        const char      *errstr;

                        memset(&addr, 0, sizeof(addr));
                        p = strchr($2, '/');
                        if (p != NULL) {
                                *p++ = '\0';
                                prefixlen = strtonum(p, 0, 128, &errstr);
                                if (errstr != NULL) {
                                        yyerror("error parsing prefix "
                                            "\"%s/%s\"", $2, p);
                                        free($2);
                                        YYERROR;
                                }
                        } else
                                prefixlen = 64;
                        if(inet_pton(AF_INET6, $2, &addr) == 0) {
                                yyerror("error parsing prefix \"%s/%d\"", $2,
                                    prefixlen);
                                free($2);
                                YYERROR;
                        }
                        mask_prefix(&addr, prefixlen);
                        ra_prefix_conf = conf_get_ra_prefix(&addr, prefixlen);
                } ra_prefix_block {
                        ra_prefix_conf = NULL;
                }
                | ra_opt_block
                ;

ra_prefix_block : '{' optnl ra_prefixopts_l '}'
                | '{' optnl '}'
                | /* empty */
                ;

ra_prefixopts_l : ra_prefixopts_l ra_prefixoptsl nl
                | ra_prefixoptsl optnl
                ;

ra_prefixoptsl  : VALID LIFETIME NUMBER {
                        ra_prefix_conf->vltime = $3;
                }
                | PREFERRED LIFETIME NUMBER {
                        ra_prefix_conf->pltime = $3;
                }
                | ONLINK yesno {
                        ra_prefix_conf->lflag = $2;
                }
                | AUTONOMOUS ADDRESS_CONFIGURATION yesno {
                        ra_prefix_conf->aflag = $3;
                }
                ;

ra_pref64_block : '{' optnl ra_pref64opts_l '}'
                | '{' optnl '}'
                | /* empty */
                ;

ra_pref64opts_l : ra_pref64opts_l ra_pref64optsl nl
                | ra_pref64optsl optnl
                ;

ra_pref64optsl  : LIFETIME NUMBER {
                        if ($2 < 0 || $2 > 65528) {
                                yyerror("Invalid nat64 prefix lifetime: %lld",
                                    $2);
                                YYERROR;
                        }
                        ra_pref64_conf->ltime = $2;
                }
                ;

dns_block       : '{' optnl dnsopts_l '}'
                | '{' optnl '}'
                | /* empty */
                ;

dnsopts_l       : dnsopts_l dnsoptsl nl
                | dnsoptsl optnl
                ;

dnsoptsl        : LIFETIME NUMBER {
                        ra_options->rdns_lifetime = $2;
                }
                | NAMESERVER nserver_block
                | SEARCH search_block
                ;
nserver_block   : '{' optnl nserveropts_l '}'
                        | '{' optnl '}'
                        | nserveroptsl
                        | /* empty */
                        ;

nserveropts_l   : nserveropts_l nserveroptsl optnl
                | nserveroptsl optnl
                ;

nserveroptsl    : STRING {
                        struct ra_rdnss_conf    *ra_rdnss_conf;
                        struct in6_addr          addr;

                        memset(&addr, 0, sizeof(addr));
                        if (inet_pton(AF_INET6, $1, &addr)
                            != 1) {
                                yyerror("error parsing nameserver address %s",
                                    $1);
                                free($1);
                                YYERROR;
                        }
                        if ((ra_rdnss_conf = calloc(1, sizeof(*ra_rdnss_conf)))
                            == NULL)
                                err(1, "%s", __func__);
                        memcpy(&ra_rdnss_conf->rdnss, &addr, sizeof(addr));
                        SIMPLEQ_INSERT_TAIL(&ra_options->ra_rdnss_list,
                            ra_rdnss_conf, entry);
                        ra_options->rdnss_count++;
                }
                ;
search_block    : '{' optnl searchopts_l '}'
                | '{' optnl '}'
                | searchoptsl
                | /* empty */
                ;

searchopts_l    : searchopts_l searchoptsl optnl
                | searchoptsl optnl
                ;

searchoptsl     : STRING {
                        struct ra_dnssl_conf    *ra_dnssl_conf;
                        size_t                   len;

                        if ((ra_dnssl_conf = calloc(1,
                            sizeof(*ra_dnssl_conf))) == NULL)
                                err(1, "%s", __func__);

                        if ((len = strlcpy(ra_dnssl_conf->search, $1,
                            sizeof(ra_dnssl_conf->search))) >=
                            sizeof(ra_dnssl_conf->search)) {
                                yyerror("search string too long");
                                free($1);
                                YYERROR;
                        }
                        if (ra_dnssl_conf->search[len] != '.') {
                                if ((len = strlcat(ra_dnssl_conf->search, ".",
                                    sizeof(ra_dnssl_conf->search))) >
                                    sizeof(ra_dnssl_conf->search)) {
                                        yyerror("search string too long");
                                        free($1);
                                        YYERROR;
                                }
                        }
                        SIMPLEQ_INSERT_TAIL(&ra_options->ra_dnssl_list,
                            ra_dnssl_conf, entry);
                        ra_options->dnssl_len += len + 1;
                }
                ;
%%

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

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);
}

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

int
lookup(char *s)
{
        /* This has to be sorted always. */
        static const struct keywords keywords[] = {
                {"address",             ADDRESS},
                {"address-configuration",       ADDRESS_CONFIGURATION},
                {"auto",                AUTO},
                {"autonomous",          AUTONOMOUS},
                {"configuration",       CONFIGURATION},
                {"default",             DEFAULT},
                {"dns",                 DNS},
                {"high",                HIGH},
                {"hop",                 HOP},
                {"include",             INCLUDE},
                {"interface",           RA_IFACE},
                {"lifetime",            LIFETIME},
                {"limit",               LIMIT},
                {"link-layer",          LINK_LAYER},
                {"low",                 LOW},
                {"managed",             MANAGED},
                {"medium",              MEDIUM},
                {"mtu",                 MTU},
                {"nameserver",          NAMESERVER},
                {"nat64",               NAT64},
                {"no",                  NO},
                {"on-link",             ONLINK},
                {"other",               OTHER},
                {"preference",          PREFERENCE},
                {"preferred",           PREFERRED},
                {"prefix",              PREFIX},
                {"reachable",           REACHABLE},
                {"retrans",             RETRANS},
                {"router",              ROUTER},
                {"search",              SEARCH},
                {"source",              SOURCE},
                {"time",                TIME},
                {"timer",               TIMER},
                {"valid",               VALID},
                {"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);
}

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, "lungetc");
                file->ungetbuf = p;
                file->ungetsize *= 2;
        }
        file->ungetbuf[file->ungetpos++] = c;
}

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);
}

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, "yylex: strdup");
                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, "yylex: strdup");
                return (token);
        }
        if (c == '\n') {
                yylval.lineno = file->lineno;
                file->lineno++;
        }
        if (c == EOF)
                return (0);
        return (c);
}

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);
}

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

        if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
                log_warn("calloc");
                return (NULL);
        }
        if ((nfile->name = strdup(name)) == NULL) {
                log_warn("strdup");
                free(nfile);
                return (NULL);
        }
        if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
                log_warn("%s", 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("malloc");
                fclose(nfile->stream);
                free(nfile->name);
                free(nfile);
                return (NULL);
        }
        TAILQ_INSERT_TAIL(&files, nfile, entry);
        return (nfile);
}

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 rad_conf *
parse_config(char *filename)
{
        struct sym              *sym, *next;
        struct ra_iface_conf    *iface;

        conf = config_new_empty();
        ra_options = NULL;

        file = pushfile(filename, 0);
        if (file == 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 ((cmd_opts & 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);
                }
        }

        if (errors) {
                clear_config(conf);
                return (NULL);
        }

        if (!SIMPLEQ_EMPTY(&conf->ra_options.ra_rdnss_list) ||
            !SIMPLEQ_EMPTY(&conf->ra_options.ra_dnssl_list)) {
                SIMPLEQ_FOREACH(iface, &conf->ra_iface_list, entry)
                        copy_dns_options(&conf->ra_options,
                            &iface->ra_options);
        }

        if (!SIMPLEQ_EMPTY(&conf->ra_options.ra_pref64_list)) {
                SIMPLEQ_FOREACH(iface, &conf->ra_iface_list, entry)
                        copy_pref64_options(&conf->ra_options,
                            &iface->ra_options);
        }

        return (conf);
}

void
copy_dns_options(const struct ra_options_conf *src, struct ra_options_conf *dst)
{
        struct ra_rdnss_conf    *ra_rdnss, *nra_rdnss;
        struct ra_dnssl_conf    *ra_dnssl, *nra_dnssl;

        if (SIMPLEQ_EMPTY(&dst->ra_rdnss_list)) {
                SIMPLEQ_FOREACH(ra_rdnss, &src->ra_rdnss_list, entry) {
                        if ((nra_rdnss = calloc(1, sizeof(*nra_rdnss))) == NULL)
                                err(1, "%s", __func__);
                        memcpy(nra_rdnss, ra_rdnss, sizeof(*nra_rdnss));
                        SIMPLEQ_INSERT_TAIL(&dst->ra_rdnss_list, nra_rdnss,
                            entry);
                }
                dst->rdnss_count = src->rdnss_count;
        }
        if (SIMPLEQ_EMPTY(&dst->ra_dnssl_list)) {
                SIMPLEQ_FOREACH(ra_dnssl, &src->ra_dnssl_list, entry) {
                        if ((nra_dnssl = calloc(1, sizeof(*nra_dnssl))) == NULL)
                                err(1, "%s", __func__);
                        memcpy(nra_dnssl, ra_dnssl, sizeof(*nra_dnssl));
                        SIMPLEQ_INSERT_TAIL(&dst->ra_dnssl_list, nra_dnssl,
                            entry);
                }
                dst->dnssl_len = src->dnssl_len;
        }
}

void
copy_pref64_options(const struct ra_options_conf *src, struct ra_options_conf
    *dst)
{
        struct ra_pref64_conf   *pref64, *npref64;

        SIMPLEQ_FOREACH(pref64, &src->ra_pref64_list, entry) {
                if ((npref64 = calloc(1, sizeof(*npref64))) == NULL)
                        err(1, "%s", __func__);
                memcpy(npref64, pref64, sizeof(*npref64));
                SIMPLEQ_INSERT_TAIL(&dst->ra_pref64_list, npref64, entry);
        }
}

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);
}

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);
}

struct ra_prefix_conf *
conf_get_ra_prefix(struct in6_addr *addr, int prefixlen)
{
        struct ra_prefix_conf   *prefix;

        if (addr == NULL) {
                if (ra_iface_conf->autoprefix != NULL)
                        return (ra_iface_conf->autoprefix);
        } else {
                SIMPLEQ_FOREACH(prefix, &ra_iface_conf->ra_prefix_list, entry) {
                        if (prefix->prefixlen == prefixlen && memcmp(addr,
                            &prefix->prefix, sizeof(*addr)) == 0)
                                return (prefix);
                }
        }

        prefix = calloc(1, sizeof(*prefix));
        if (prefix == NULL)
                err(1, "%s", __func__);
        prefix->prefixlen = prefixlen;
        prefix->vltime = ADV_VALID_LIFETIME;
        prefix->pltime = ADV_PREFERRED_LIFETIME;
        prefix->lflag = 1;
        prefix->aflag = 1;

        if (addr == NULL)
                ra_iface_conf->autoprefix = prefix;
        else {
                prefix->prefix = *addr;
                SIMPLEQ_INSERT_TAIL(&ra_iface_conf->ra_prefix_list, prefix,
                    entry);
        }

        return (prefix);
}

struct ra_pref64_conf *
conf_get_ra_pref64(struct in6_addr *addr, int prefixlen)
{
        struct ra_pref64_conf   *pref64;

        SIMPLEQ_FOREACH(pref64, &ra_options->ra_pref64_list, entry) {
                if (pref64->prefixlen == prefixlen && memcmp(addr,
                    &pref64->prefix, sizeof(*addr)) == 0)
                        return (pref64);
        }

        pref64 = calloc(1, sizeof(*pref64));
        if (pref64 == NULL)
                err(1, "%s", __func__);
        pref64->prefixlen = prefixlen;
        pref64->ltime = ADV_DEFAULT_LIFETIME;
        pref64->prefix = *addr;
        SIMPLEQ_INSERT_TAIL(&ra_options->ra_pref64_list, pref64, entry);

        return (pref64);
}

struct ra_iface_conf *
conf_get_ra_iface(char *name)
{
        struct ra_iface_conf    *iface;
        size_t                   n;

        SIMPLEQ_FOREACH(iface, &conf->ra_iface_list, entry) {
                if (strcmp(name, iface->name) == 0)
                        return (iface);
        }

        iface = calloc(1, sizeof(*iface));
        if (iface == NULL)
                errx(1, "%s: calloc", __func__);
        n = strlcpy(iface->name, name, sizeof(iface->name));
        if (n >= sizeof(iface->name))
                errx(1, "%s: name too long", __func__);

        /* Inherit attributes set in global section. */
        iface->ra_options = conf->ra_options;

        SIMPLEQ_INIT(&iface->ra_prefix_list);
        SIMPLEQ_INIT(&iface->ra_options.ra_rdnss_list);
        iface->ra_options.rdnss_count = 0;
        SIMPLEQ_INIT(&iface->ra_options.ra_dnssl_list);
        iface->ra_options.dnssl_len = 0;
        SIMPLEQ_INIT(&iface->ra_options.ra_pref64_list);

        SIMPLEQ_INSERT_TAIL(&conf->ra_iface_list, iface, entry);

        return (iface);
}

void
clear_config(struct rad_conf *xconf)
{
        struct ra_iface_conf    *iface;

        free_dns_options(&xconf->ra_options);

        while((iface = SIMPLEQ_FIRST(&xconf->ra_iface_list)) != NULL) {
                SIMPLEQ_REMOVE_HEAD(&xconf->ra_iface_list, entry);
                free_ra_iface_conf(iface);
        }

        free(xconf);
}