avahi-core/domain-util.c

/***
  This file is part of avahi.

  avahi is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation; either version 2.1 of the
  License, or (at your option) any later version.

  avahi is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
  Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with avahi; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/utsname.h>
#include <stdio.h>
#include <inttypes.h>

#include <avahi-common/malloc.h>

#include "log.h"
#include "domain-util.h"
#include "util.h"

static void strip_bad_chars(char *s) {
    char *p, *d;

    s[strcspn(s, ".")] = 0;

    for (p = s, d = s; *p; p++)
        if ((*p >= 'a' && *p <= 'z') ||
            (*p >= 'A' && *p <= 'Z') ||
            (*p >= '0' && *p <= '9') ||
            *p == '-')
            *(d++) = *p;

    *d = 0;
}

#ifdef __linux__
static int load_lsb_distrib_id(char *ret_s, size_t size) {
    FILE *f;

    assert(ret_s);
    assert(size > 0);

    if (!(f = fopen("/etc/lsb-release", "r")))
        return -1;

    while (!feof(f)) {
        char ln[256], *p;

        if (!fgets(ln, sizeof(ln), f))
            break;

        if (strncmp(ln, "DISTRIB_ID=", 11))
            continue;

        p = ln + 11;
        p += strspn(p, "\"");
        p[strcspn(p, "\"")] = 0;

        snprintf(ret_s, size, "%s", p);

        fclose(f);
        return 0;
    }

    fclose(f);
    return -1;
}
#endif

// Returns a randomized MAC address.
uint64_t random_host_id() {
    const uint64_t kMacAddressMask = 0xFFFFFFFFFFFF;
    const uint64_t kMacMulticastBit = 0x010000000000;
    const uint64_t kMacLocalBit = 0x020000000000;
    static uint64_t random_id = 0;

    if (!random_id) {
        // The random seed has been initialized in avahi-daemon/main.c
        random_id = (((uint64_t) rand()) << 32) | (uint64_t) rand();
        if (!random_id) {
            random_id = 1;
        }
        random_id = (random_id | kMacLocalBit) & (kMacAddressMask & ~kMacMulticastBit);
    }
    return random_id;
}

char *avahi_get_host_name(char *ret_s, size_t size) {
    assert(ret_s);
    assert(size > 0);

    // For Matter spec compliance, we use a host name in the form of a MAC address.
    snprintf(ret_s, size, "%012" PRIX64 , random_host_id());

    if (size >= AVAHI_LABEL_MAX)
	ret_s[AVAHI_LABEL_MAX-1] = 0;

    return ret_s;
}

char *avahi_get_host_name_strdup(void) {
    char t[AVAHI_DOMAIN_NAME_MAX];

    if (!(avahi_get_host_name(t, sizeof(t))))
        return NULL;

    return avahi_strdup(t);
}

int avahi_binary_domain_cmp(const char *a, const char *b) {
    assert(a);
    assert(b);

    if (a == b)
        return 0;

    for (;;) {
        char ca[AVAHI_LABEL_MAX], cb[AVAHI_LABEL_MAX], *p;
        int r;

        p = avahi_unescape_label(&a, ca, sizeof(ca));
        assert(p);
        p = avahi_unescape_label(&b, cb, sizeof(cb));
        assert(p);

        if ((r = strcmp(ca, cb)))
            return r;

        if (!*a && !*b)
            return 0;
    }
}

int avahi_domain_ends_with(const char *domain, const char *suffix) {
    assert(domain);
    assert(suffix);

    for (;;) {
        char dummy[AVAHI_LABEL_MAX], *r;

        if (*domain == 0)
            return 0;

        if (avahi_domain_equal(domain, suffix))
            return 1;

        r = avahi_unescape_label(&domain, dummy, sizeof(dummy));
        assert(r);
    }
}