source: mainline/uspace/lib/c/generic/inet/host.c@ eec201d

/*
 * Copyright (c) 2016 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libc
 * @{
 */
/** @file Internet host specification
 *
 * Either a host name or an address.
 */

#include <assert.h>
#include <errno.h>
#include <inet/addr.h>
#include <inet/dnsr.h>
#include <inet/host.h>
#include <inet/hostname.h>
#include <stdio.h>
#include <stdlib.h>
#include <str.h>

/** Parse host string.
 *
 * @param str Host string
 * @param rhost Place to store pointer to new host structure
 * @param endptr Place to store pointer to next character in string or @c NULL
 *
 * @return EOK on success. EINVAL if @a str does not start with a valid
 *         host specification or if @a endptr is @c NULL and @a str contains
 *         extra characters at the end. ENOMEM if out of memory
 */
errno_t inet_host_parse(const char *str, inet_host_t **rhost,
    char **endptr)
{
        inet_host_t *host;
        inet_addr_t addr;
        char *name;
        char *aend;
        errno_t rc;

        host = calloc(1, sizeof(inet_host_t));
        if (host == NULL)
                return ENOMEM;

        /* Try address */
        rc = inet_addr_parse(str, &addr, &aend);
        if (rc == EOK) {
                host->hform = inet_host_addr;
                host->host.addr = addr;
                goto have_host;
        }

        /* Try <hostname> */
        rc = inet_hostname_parse(str, &name, &aend);
        if (rc == EOK) {
                host->hform = inet_host_name;
                host->host.name = name;
                goto have_host;
        }

        free(host);
        return EINVAL;

have_host:
        if (*aend != '\0' && endptr == NULL) {
                /* Extra characters */
                free(host);
                return EINVAL;
        }

        *rhost = host;
        if (endptr != NULL)
                *endptr = (char *)aend;
        return EOK;
}

/** Convert host structure to string representation.
 *
 * @param host Host structure
 * @param rstr Place to store pointer to new string
 * @return EOK on success, ENOMEM if out of memory
 */
errno_t inet_host_format(inet_host_t *host, char **rstr)
{
        errno_t rc;
        char *str = NULL;

        switch (host->hform) {
        case inet_host_addr:
                rc = inet_addr_format(&host->host.addr, &str);
                if (rc != EOK) {
                        assert(rc == ENOMEM);
                        return ENOMEM;
                }

                break;
        case inet_host_name:
                str = str_dup(host->host.name);
                if (str == NULL)
                        return ENOMEM;
                break;
        }

        *rstr = str;
        return EOK;
}

/** Destroy host structure.
 *
 * @param host Host structure or @c NULL
 */
void inet_host_destroy(inet_host_t *host)
{
        if (host == NULL)
                return;

        switch (host->hform) {
        case inet_host_addr:
                break;
        case inet_host_name:
                free(host->host.name);
                break;
        }

        free(host);
}

/** Look up first address corresponding to host.
 *
 * If host contains a host name, name resolution is performed.
 *
 * @param host Host structure
 * @param version Desired IP version (ip_any to get any version)
 * @param addr Place to store address
 *
 * @reutrn EOK on success, ENOENT on resolurion failure
 */
errno_t inet_host_lookup_one(inet_host_t *host, ip_ver_t version, inet_addr_t *addr)
{
        dnsr_hostinfo_t *hinfo = NULL;
        errno_t rc;

        switch (host->hform) {
        case inet_host_addr:
                *addr = host->host.addr;
                break;
        case inet_host_name:
                rc = dnsr_name2host(host->host.name, &hinfo, version);
                if (rc != EOK) {
                        dnsr_hostinfo_destroy(hinfo);
                        return ENOENT;
                }

                *addr = hinfo->addr;
                dnsr_hostinfo_destroy(hinfo);
                break;
        }

        return EOK;
}

/** Look up first address corresponding to host string.
 *
 * If host contains a host name, name resolution is performed.
 *
 * @param str Host string
 * @param version Desired IP version (ip_any to get any version)
 * @param addr Place to store address
 * @param endptr Place to store pointer to next character in string or @c NULL
 * @param errmsg Place to store pointer to error message (no need to free it)
 *               or @c NULL
 *
 * @return EOK on success. EINVAL if @a str has incorrect format or if
 *         @a endptr is @c NULL and @a str contains extra characters at
 *         the end. ENOENT if host was not found during resolution,
 *         ENOMEM if out of memory
 */
errno_t inet_host_plookup_one(const char *str, ip_ver_t version, inet_addr_t *addr,
    char **endptr, const char **errmsg)
{
        inet_host_t *host = NULL;
        char *eptr;
        errno_t rc;

        rc = inet_host_parse(str, &host, endptr != NULL ? &eptr : NULL);
        if (rc != EOK) {
                switch (rc) {
                case EINVAL:
                        if (errmsg != NULL)
                                *errmsg = "Invalid format";
                        goto error;
                case ENOMEM:
                        if (errmsg != NULL)
                                *errmsg = "Out of memory";
                        goto error;
                default:
                        assert(false);
                }
        }

        rc = inet_host_lookup_one(host, version, addr);
        if (rc != EOK) {
                /* XXX Distinguish between 'not found' and other error */
                rc = ENOENT;
                if (errmsg != NULL)
                        *errmsg = "Name resolution failed";
                goto error;
        }

        inet_host_destroy(host);
        if (endptr != NULL)
                *endptr = eptr;
        return EOK;
error:
        inet_host_destroy(host);
        return rc;
}

/** @}
 */