common/irs/dns_sv.c

/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996,1999 by Internet Software Consortium.
 *
 * 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 ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static const char rcsid[] = "$Id: dns_sv.c,v 1.5 2005/04/27 04:56:23 sra Exp $";
#endif

/* Imports */

#include "port_before.h"

#include <sys/types.h>
#include <netinet/in.h>

#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <ctype.h>
#include <stdlib.h>
#include <errno.h>

#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>

#include <isc/memcluster.h>
#include <irs.h>

#include "port_after.h"

#include "irs_p.h"
#include "hesiod.h"
#include "dns_p.h"

/* Definitions */

struct pvt {
    struct dns_p *      dns;
    struct servent      serv;
    char *          svbuf;
    struct __res_state *    res;
    void            (*free_res)(void *);
};

/* Forward. */

static void             sv_close(struct irs_sv *);
static struct servent *     sv_byname(struct irs_sv *,
                      const char *, const char *);
static struct servent *     sv_byport(struct irs_sv *, int, const char *);
static struct servent *     sv_next(struct irs_sv *);
static void         sv_rewind(struct irs_sv *);
static void         sv_minimize(struct irs_sv *);
#ifdef SV_RES_SETGET
static struct __res_state * sv_res_get(struct irs_sv *);
static void         sv_res_set(struct irs_sv *,
                       struct __res_state *,
                       void (*)(void *));
#endif

static struct servent *     parse_hes_list(struct irs_sv *,
                           char **, const char *);

/* Public */

struct irs_sv *
irs_dns_sv(struct irs_acc *this) {
    struct dns_p *dns = (struct dns_p *)this->private;
    struct irs_sv *sv;
    struct pvt *pvt;

    if (!dns || !dns->hes_ctx) {
        errno = ENODEV;
        return (NULL);
    }
    if (!(pvt = memget(sizeof *pvt))) {
        errno = ENOMEM;
        return (NULL);
    }
    memset(pvt, 0, sizeof *pvt);
    pvt->dns = dns;
    if (!(sv = memget(sizeof *sv))) {
        memput(pvt, sizeof *pvt);
        errno = ENOMEM;
        return (NULL);
    }
    memset(sv, 0x5e, sizeof *sv);
    sv->private = pvt;
    sv->byname = sv_byname;
    sv->byport = sv_byport;
    sv->next = sv_next;
    sv->rewind = sv_rewind;
    sv->close = sv_close;
    sv->minimize = sv_minimize;
#ifdef SV_RES_SETGET
    sv->res_get = sv_res_get;
    sv->res_set = sv_res_set;
#else
    sv->res_get = NULL; /*%< sv_res_get; */
    sv->res_set = NULL; /*%< sv_res_set; */
#endif
    return (sv);
}

/* Methods */

static void
sv_close(struct irs_sv *this) {
    struct pvt *pvt = (struct pvt *)this->private;

    if (pvt->serv.s_aliases)
        free(pvt->serv.s_aliases);
    if (pvt->svbuf)
        free(pvt->svbuf);

    if (pvt->res && pvt->free_res)
        (*pvt->free_res)(pvt->res);
    memput(pvt, sizeof *pvt);
    memput(this, sizeof *this);
}

static struct servent *
sv_byname(struct irs_sv *this, const char *name, const char *proto) {
    struct pvt *pvt = (struct pvt *)this->private;
    struct dns_p *dns = pvt->dns;
    struct servent *s;
    char **hes_list;

    if (!(hes_list = hesiod_resolve(dns->hes_ctx, name, "service")))
        return (NULL);

    s = parse_hes_list(this, hes_list, proto);
    hesiod_free_list(dns->hes_ctx, hes_list);
    return (s);
}

static struct servent *
sv_byport(struct irs_sv *this, int port, const char *proto) {
    struct pvt *pvt = (struct pvt *)this->private;
    struct dns_p *dns = pvt->dns;
    struct servent *s;
    char portstr[16];
    char **hes_list;

    sprintf(portstr, "%d", ntohs(port));
    if (!(hes_list = hesiod_resolve(dns->hes_ctx, portstr, "port")))
        return (NULL);

    s = parse_hes_list(this, hes_list, proto);
    hesiod_free_list(dns->hes_ctx, hes_list);
    return (s);
}

static struct servent *
sv_next(struct irs_sv *this) {
    UNUSED(this);
    errno = ENODEV;
    return (NULL);
}

static void
sv_rewind(struct irs_sv *this) {
    UNUSED(this);
    /* NOOP */
}

/* Private */

static struct servent *
parse_hes_list(struct irs_sv *this, char **hes_list, const char *proto) {
    struct pvt *pvt = (struct pvt *)this->private;
    char *p, *cp, **cpp, **new;
    int proto_len;
    int num = 0;
    int max = 0;

    for (cpp = hes_list; *cpp; cpp++) {
        cp = *cpp;

        /* Strip away comments, if any. */
        if ((p = strchr(cp, '#')))
            *p = 0;

        /* Check to make sure the protocol matches. */
        p = cp;
        while (*p && !isspace((unsigned char)*p))
            p++;
        if (!*p)
            continue;
        if (proto) {
             proto_len = strlen(proto);
             if (strncasecmp(++p, proto, proto_len) != 0)
              continue;
             if (p[proto_len] && !isspace(p[proto_len]&0xff))
              continue;
        }
        /* OK, we've got a live one.  Let's parse it for real. */
        if (pvt->svbuf)
            free(pvt->svbuf);
        pvt->svbuf = strdup(cp);

        p = pvt->svbuf;
        pvt->serv.s_name = p;
        while (*p && !isspace(*p&0xff))
            p++;
        if (!*p)
            continue;
        *p++ = '\0';

        pvt->serv.s_proto = p;
        while (*p && !isspace(*p&0xff))
            p++;
        if (!*p)
            continue;
        *p++ = '\0';

        pvt->serv.s_port = htons((u_short) atoi(p));
        while (*p && !isspace(*p&0xff))
            p++;
        if (*p)
            *p++ = '\0';

        while (*p) {
            if ((num + 1) >= max || !pvt->serv.s_aliases) {
                max += 10;
                new = realloc(pvt->serv.s_aliases,
                          max * sizeof(char *));
                if (!new) {
                    errno = ENOMEM;
                    goto cleanup;
                }
                pvt->serv.s_aliases = new;
            }
            pvt->serv.s_aliases[num++] = p;
            while (*p && !isspace(*p&0xff))
                p++;
            if (*p)
                *p++ = '\0';
        }
        if (!pvt->serv.s_aliases)
            pvt->serv.s_aliases = malloc(sizeof(char *));
        if (!pvt->serv.s_aliases)
            goto cleanup;
        pvt->serv.s_aliases[num] = NULL;
        return (&pvt->serv);
    }

 cleanup:
    if (pvt->serv.s_aliases) {
        free(pvt->serv.s_aliases);
        pvt->serv.s_aliases = NULL;
    }
    if (pvt->svbuf) {
        free(pvt->svbuf);
        pvt->svbuf = NULL;
    }
    return (NULL);
}

static void
sv_minimize(struct irs_sv *this) {
    UNUSED(this);
    /* NOOP */
}

#ifdef SV_RES_SETGET
static struct __res_state *
sv_res_get(struct irs_sv *this) {
    struct pvt *pvt = (struct pvt *)this->private;
    struct dns_p *dns = pvt->dns;

    return (__hesiod_res_get(dns->hes_ctx));
}

static void
sv_res_set(struct irs_sv *this, struct __res_state * res,
       void (*free_res)(void *)) {
    struct pvt *pvt = (struct pvt *)this->private;
    struct dns_p *dns = pvt->dns;

    __hesiod_res_set(dns->hes_ctx, res, free_res);
}
#endif

/*! \file */