root/usr.sbin/dvmrpd/parse.y
/*      $OpenBSD: parse.y,v 1.40 2021/10/15 15:01:27 naddy Exp $ */

/*
 * Copyright (c) 2004, 2005, 2006 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/time.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <ctype.h>
#include <err.h>
#include <limits.h>
#include <unistd.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>

#include "igmp.h"
#include "dvmrp.h"
#include "dvmrpd.h"
#include "dvmrpe.h"
#include "log.h"

TAILQ_HEAD(files, file)          files = TAILQ_HEAD_INITIALIZER(files);
static struct file {
        TAILQ_ENTRY(file)        entry;
        FILE                    *stream;
        char                    *name;
        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              lgetc(int);
int              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 *);

static struct dvmrpd_conf       *conf;
char                            *start_state;
struct iface                    *iface = NULL;

static struct {
        u_int32_t        probe_interval;
        u_int32_t        query_interval;
        u_int32_t        query_resp_interval;
        u_int32_t        startup_query_interval;
        u_int32_t        startup_query_cnt;
        u_int32_t        last_member_query_interval;
        u_int32_t        last_member_query_cnt;
        u_int32_t        dead_interval;
        u_int16_t        metric;
        u_int8_t         robustness;
        u_int8_t         igmp_version;
} *defs, *grdefs, globaldefs, groupdefs, ifacedefs;

void             clear_config(struct dvmrpd_conf *xconf);
struct iface    *conf_get_if(struct kif *);
struct iface    *new_group(void);

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

%}

%token  INTERFACE FIBUPDATE
%token  GROUP
%token  METRIC PASSIVE
%token  ROBUSTNESS QUERYINTERVAL QUERYRESPINTERVAL
%token  STARTUPQUERYINTERVAL STARTUPQUERYCNT
%token  LASTMEMBERQUERYINTERVAL LASTMEMBERQUERYCNT
%token  IGMPVERSION
%token  ERROR
%token  <v.string>      STRING
%token  <v.number>      NUMBER
%type   <v.number>      yesno
%type   <v.string>      string

%%

grammar         : /* empty */
                | grammar '\n'
                | grammar conf_main '\n'
                | grammar varset '\n'
                | grammar interface '\n'
                | grammar group '\n'
                | grammar error '\n'            { file->errors++; }
                ;

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

yesno           : STRING {
                        if (!strcmp($1, "yes"))
                                $$ = 1;
                        else if (!strcmp($1, "no"))
                                $$ = 0;
                        else {
                                yyerror("syntax error, "
                                    "either yes or no expected");
                                free($1);
                                YYERROR;
                        }
                        free($1);
                }
                ;

varset          : STRING '=' string             {
                        char *s = $1;
                        if (conf->opts & DVMRPD_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       : FIBUPDATE yesno {
                        if ($2 == 0)
                                conf->flags |= DVMRPD_FLAG_NO_FIB_UPDATE;
                        else
                                conf->flags &= ~DVMRPD_FLAG_NO_FIB_UPDATE;
                }
                | defaults
                ;

defaults        : LASTMEMBERQUERYCNT NUMBER {
                        if ($2 < MIN_LAST_MEMBER_QUERY_CNT ||
                            $2 > MAX_LAST_MEMBER_QUERY_CNT) {
                                yyerror("last-member-query-count out of "
                                    "range (%d-%d)",
                                    MIN_LAST_MEMBER_QUERY_CNT,
                                    MAX_LAST_MEMBER_QUERY_CNT);
                                YYERROR;
                        }
                        defs->last_member_query_cnt = $2;
                }
                | LASTMEMBERQUERYINTERVAL NUMBER {
                        if ($2 < MIN_LAST_MEMBER_QUERY_INTERVAL ||
                            $2 > MAX_LAST_MEMBER_QUERY_INTERVAL) {
                                yyerror("last-member-query-interval out of "
                                    "range (%d-%d)",
                                    MIN_LAST_MEMBER_QUERY_INTERVAL,
                                    MAX_LAST_MEMBER_QUERY_INTERVAL);
                                YYERROR;
                        }
                        defs->last_member_query_interval = $2;
                }
                | METRIC NUMBER {
                        if ($2 < MIN_METRIC || $2 > MAX_METRIC) {
                                yyerror("metric out of range (%d-%d)",
                                    MIN_METRIC, MAX_METRIC);
                                YYERROR;
                        }
                        defs->metric = $2;
                }
                | QUERYINTERVAL NUMBER {
                        if ($2 < MIN_QUERY_INTERVAL ||
                            $2 > MAX_QUERY_INTERVAL) {
                                yyerror("query-interval out of range (%d-%d)",
                                    MIN_QUERY_INTERVAL, MAX_QUERY_INTERVAL);
                                YYERROR;
                        }
                        defs->query_interval = $2;
                }
                | QUERYRESPINTERVAL NUMBER {
                        if ($2 < MIN_QUERY_RESP_INTERVAL ||
                            $2 > MAX_QUERY_RESP_INTERVAL) {
                                yyerror("query-response-interval out of "
                                    "range (%d-%d)",
                                    MIN_QUERY_RESP_INTERVAL,
                                    MAX_QUERY_RESP_INTERVAL);
                                YYERROR;
                        }
                        defs->query_resp_interval = $2;
                }
                | ROBUSTNESS NUMBER {
                        if ($2 < MIN_ROBUSTNESS || $2 > MAX_ROBUSTNESS) {
                                yyerror("robustness out of range (%d-%d)",
                                    MIN_ROBUSTNESS, MAX_ROBUSTNESS);
                                YYERROR;
                        }
                        defs->robustness = $2;
                }
                | STARTUPQUERYCNT NUMBER {
                        if ($2 < MIN_STARTUP_QUERY_CNT ||
                            $2 > MAX_STARTUP_QUERY_CNT) {
                                yyerror("startup-query-count out of "
                                    "range (%d-%d)",
                                    MIN_STARTUP_QUERY_CNT,
                                    MAX_STARTUP_QUERY_CNT);
                                YYERROR;
                        }
                        defs->startup_query_cnt = $2;
                }
                | STARTUPQUERYINTERVAL NUMBER {
                        if ($2 < MIN_STARTUP_QUERY_INTERVAL ||
                            $2 > MAX_STARTUP_QUERY_INTERVAL) {
                                yyerror("startup-query-interval out of "
                                    "range (%d-%d)",
                                    MIN_STARTUP_QUERY_INTERVAL,
                                    MAX_STARTUP_QUERY_INTERVAL);
                                YYERROR;
                        }
                        defs->startup_query_interval = $2;
                }
                | IGMPVERSION NUMBER {
                        if ($2 < MIN_IGMP_VERSION ||
                            $2 > MAX_IGMP_VERSION) {
                                yyerror("igmp-version out of range (%d-%d)",
                                    MIN_IGMP_VERSION, MAX_IGMP_VERSION);
                                YYERROR;
                        }
                        defs->igmp_version = $2;
                }
                ;

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;
                        LIST_INSERT_HEAD(&conf->iface_list, iface, entry);

                        memcpy(&ifacedefs, defs, sizeof(ifacedefs));
                        defs = &ifacedefs;
                } interface_block {
                        iface->probe_interval = defs->probe_interval;
                        iface->query_interval = defs->query_interval;
                        iface->query_resp_interval = defs->query_resp_interval;
                        iface->startup_query_interval =
                            defs->startup_query_interval;
                        iface->startup_query_cnt = defs->startup_query_cnt;
                        iface->last_member_query_interval =
                            defs->last_member_query_interval;
                        iface->last_member_query_cnt =
                            defs->last_member_query_cnt;
                        iface->dead_interval = defs->dead_interval;
                        iface->metric = defs->metric;
                        iface->robustness = defs->robustness;
                        iface->igmp_version = defs->igmp_version;
                        if (grdefs)
                                defs = grdefs;
                        else
                                defs = &globaldefs;
                        iface = NULL;
                }
                ;

interface_block : '{' optnl interfaceopts_l '}'
                | '{' optnl '}'
                |
                ;

interfaceopts_l : interfaceopts_l interfaceoptsl
                | interfaceoptsl
                ;

interfaceoptsl  : PASSIVE nl            { iface->passive = 1; }
                | defaults nl
                ;

group           : GROUP optnl '{' optnl {
                        memcpy(&groupdefs, defs, sizeof(groupdefs));
                        grdefs = defs = &groupdefs;
                }
                    groupopts_l '}' {
                        grdefs = NULL;
                        defs = &globaldefs;
                }
                ;

groupopts_l     : groupopts_l groupoptsl
                | groupoptsl
                ;

groupoptsl      : interface nl
                | defaults nl
                | error nl
                ;

%%

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[] = {
                {"fib-update",                  FIBUPDATE},
                {"group",                       GROUP},
                {"igmp-version",                IGMPVERSION},
                {"interface",                   INTERFACE},
                {"last-member-query-count",     LASTMEMBERQUERYCNT},
                {"last-member-query-interval",  LASTMEMBERQUERYINTERVAL},
                {"metric",                      METRIC},
                {"passive",                     PASSIVE},
                {"query-interval",              QUERYINTERVAL},
                {"query-response-interval",     QUERYRESPINTERVAL},
                {"robustness",                  ROBUSTNESS},
                {"startup-query-count",         STARTUPQUERYCNT},
                {"startup-query-interval",      STARTUPQUERYINTERVAL}
        };
        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 MAXPUSHBACK     128

char    *parsebuf;
int      parseindex;
char     pushback_buffer[MAXPUSHBACK];
int      pushback_index = 0;

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

        if (parsebuf) {
                /* Read character from the parsebuffer instead of input. */
                if (parseindex >= 0) {
                        c = (unsigned char)parsebuf[parseindex++];
                        if (c != '\0')
                                return (c);
                        parsebuf = NULL;
                } else
                        parseindex++;
        }

        if (pushback_index)
                return ((unsigned char)pushback_buffer[--pushback_index]);

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

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

        while (c == EOF) {
                if (file == topfile || popfile() == EOF)
                        return (EOF);
                c = getc(file->stream);
        }
        return (c);
}

int
lungetc(int c)
{
        if (c == EOF)
                return (EOF);
        if (parsebuf) {
                parseindex--;
                if (parseindex >= 0)
                        return (c);
        }
        if (pushback_index + 1 >= MAXPUSHBACK)
                return (EOF);
        pushback_buffer[pushback_index++] = c;
        return (c);
}

int
findeol(void)
{
        int     c;

        parsebuf = NULL;

        /* skip to either EOF or the first real EOL */
        while (1) {
                if (pushback_index)
                        c = (unsigned char)pushback_buffer[--pushback_index];
                else
                        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 == '$' && parsebuf == NULL) {
                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());
                }
                parsebuf = val;
                parseindex = 0;
                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);
}

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("%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 = 1;
        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);
        file = prev;
        return (file ? 0 : EOF);
}

struct dvmrpd_conf *
parse_config(char *filename, int opts)
{
        int              errors = 0;
        struct sym      *sym, *next;
        struct timeval   now;

        if ((conf = calloc(1, sizeof(struct dvmrpd_conf))) == NULL) {
                errx(1, "parse_config calloc");
                return (NULL);
        }

        defs = &globaldefs;
        defs->probe_interval = DEFAULT_PROBE_INTERVAL;
        defs->last_member_query_cnt = DEFAULT_LAST_MEMBER_QUERY_CNT;
        defs->last_member_query_interval = DEFAULT_LAST_MEMBER_QUERY_INTERVAL;
        defs->metric = DEFAULT_METRIC;
        defs->query_interval = DEFAULT_QUERY_INTERVAL;
        defs->query_resp_interval = DEFAULT_QUERY_RESP_INTERVAL;
        defs->robustness = DEFAULT_ROBUSTNESS;
        defs->startup_query_cnt = DEFAULT_STARTUP_QUERY_CNT;
        defs->startup_query_interval = DEFAULT_STARTUP_QUERY_INTERVAL;
        defs->igmp_version = DEFAULT_IGMP_VERSION;
        defs->dead_interval = NBR_TMOUT;

        if ((file = pushfile(filename, 1)) == NULL) {
                free(conf);
                return (NULL);
        }
        topfile = file;

        gettimeofday(&now, NULL);
        conf->gen_id = (u_int32_t)now.tv_sec;   /* for a while after 2038 */
        conf->opts = opts;

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

        /* Free macros and check which have not been used. */
        TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
                if ((conf->opts & DVMRPD_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);
        }

        return (conf);
}

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 iface *
conf_get_if(struct kif *kif)
{
        struct iface    *i;

        if (kif->ifindex >= MAXVIFS) {
                yyerror("interface %s index too large", kif->ifname);
                return (NULL);
        }

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

        i = if_new(kif);
        i->passive = 0;
        i->recv_query_resp_interval = DEFAULT_QUERY_RESP_INTERVAL;

        return (i);
}

void
clear_config(struct dvmrpd_conf *xconf)
{
        /* XXX clear conf */
                /* ... */
}