/***

  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 <string.h>

#include <unistd.h>

#include <fcntl.h>

#include <errno.h>

#include <limits.h>

#include <stdio.h>

#include <ctype.h>

#include <stdlib.h>

#include <assert.h>

#include "domain.h"

#include "malloc.h"

#include "error.h"

#include "address.h"

#include "utf8.h"

/* Read the first label from string *name, unescape "\" and write it to dest */

char *avahi_unescape_label(const char **name, char *dest, size_t size) {

    unsigned i = 0;

    char *d;

    assert(dest);

    assert(size > 0);

    assert(name);

    d = dest;

    for (;;) {

        if (i >= size)

            return NULL;

        if (**name == '.') {

            (*name)++;

            break;

        }

        if (**name == 0)

            break;

        if (**name == '\\') {

            /* Escaped character */

            (*name) ++;

            if (**name == 0)

                /* Ending NUL */

                return NULL;

            else if (**name == '\\' || **name == '.') {

                /* Escaped backslash or dot */

                *(d++) = *((*name) ++);

                i++;

            } else if (isdigit(**name)) {

                int n;

                /* Escaped literal ASCII character */

                if (!isdigit(*(*name+1)) || !isdigit(*(*name+2)))

                    return NULL;

                n = ((uint8_t) (**name - '0') * 100) + ((uint8_t) (*(*name+1) - '0') * 10) + ((uint8_t) (*(*name +2) - '0'));

                if (n > 255 || n == 0)

                    return NULL;

                *(d++) = (char) n;

                i++;

                (*name) += 3;

            } else

                return NULL;

        } else {

            /* Normal character */

            *(d++) = *((*name) ++);

            i++;

        }

    }

    assert(i < size);

    *d = 0;

    if (!avahi_utf8_valid(dest))

        return NULL;

    return dest;

}

/* Escape "\" and ".", append \0 */

char *avahi_escape_label(const char* src, size_t src_length, char **ret_name, size_t *ret_size) {

    char *r;

    assert(src);

    assert(ret_name);

    assert(*ret_name);

    assert(ret_size);

    assert(*ret_size > 0);

    r = *ret_name;

    while (src_length > 0) {

        if (*src == '.' || *src == '\\') {

            /* Dot or backslash */

            if (*ret_size < 3)

                return NULL;

            *((*ret_name) ++) = '\\';

            *((*ret_name) ++) = *src;

            (*ret_size) -= 2;

        } else if (

            *src == '_' ||

            *src == '-' ||

            (*src >= '0' && *src <= '9') ||

            (*src >= 'a' && *src <= 'z') ||

            (*src >= 'A' && *src <= 'Z')) {

            /* Proper character */

            if (*ret_size < 2)

                return NULL;

            *((*ret_name)++) = *src;

            (*ret_size) --;

        } else {

            /* Everything else */

            if (*ret_size < 5)

                return NULL;

            *((*ret_name) ++) = '\\';

            *((*ret_name) ++) = '0' + (char)  ((uint8_t) *src / 100);

            *((*ret_name) ++) = '0' + (char) (((uint8_t) *src / 10) % 10);

            *((*ret_name) ++) = '0' + (char)  ((uint8_t) *src % 10);

            (*ret_size) -= 4;

        }

        src_length --;

        src++;

    }

    **ret_name = 0;

    return r;

}

char *avahi_normalize_name(const char *s, char *ret_s, size_t size) {

    int empty = 1;

    char *r;

    assert(s);

    assert(ret_s);

    assert(size > 0);

    r = ret_s;

    *ret_s = 0;

    while (*s) {

        char label[AVAHI_LABEL_MAX];

        if (!(avahi_unescape_label(&s, label, sizeof(label))))

            return NULL;

        if (label[0] == 0) {

            if (*s == 0 && empty)

                return ret_s;

            return NULL;

        }

        if (!empty) {

            if (size < 2)

                return NULL;

            *(r++) = '.';

            size--;

        } else

            empty = 0;

        if (!(avahi_escape_label(label, strlen(label), &r, &size)))

            return NULL;

    }

    return ret_s;

}

char *avahi_normalize_name_strdup(const char *s) {

    char t[AVAHI_DOMAIN_NAME_MAX];

    assert(s);

    if (!(avahi_normalize_name(s, t, sizeof(t))))

        return NULL;

    return avahi_strdup(t);

}

int avahi_domain_equal(const char *a, const char *b) {

    assert(a);

    assert(b);

    if (a == b)

        return 1;

    for (;;) {

        char ca[AVAHI_LABEL_MAX], cb[AVAHI_LABEL_MAX], *r;

        r = avahi_unescape_label(&a, ca, sizeof(ca));

        assert(r);

        r = avahi_unescape_label(&b, cb, sizeof(cb));

        assert(r);

        if (strcasecmp(ca, cb))

            return 0;

        if (!*a && !*b)

            return 1;

    }

    return 1;

}

int avahi_is_valid_service_type_generic(const char *t) {

    assert(t);

    if (strlen(t) >= AVAHI_DOMAIN_NAME_MAX || !*t)

        return 0;

    do {

        char label[AVAHI_LABEL_MAX];

        if (!(avahi_unescape_label(&t, label, sizeof(label))))

            return 0;

        if (strlen(label) <= 2 || label[0] != '_')

            return 0;

    } while (*t);

    return 1;

}

int avahi_is_valid_service_type_strict(const char *t) {

    char label[AVAHI_LABEL_MAX];

    assert(t);

    if (strlen(t) >= AVAHI_DOMAIN_NAME_MAX || !*t)

        return 0;

    /* Application name */

    if (!(avahi_unescape_label(&t, label, sizeof(label))))

        return 0;

    if (strlen(label) <= 2 || label[0] != '_')

        return 0;

    if (!*t)

        return 0;

    /* _tcp or _udp boilerplate */

    if (!(avahi_unescape_label(&t, label, sizeof(label))))

        return 0;

    if (strcasecmp(label, "_tcp") && strcasecmp(label, "_udp"))

        return 0;

    if (*t)

        return 0;

    return 1;

}

const char *avahi_get_type_from_subtype(const char *t) {

    char label[AVAHI_LABEL_MAX];

    const char *ret;

    assert(t);

    if (strlen(t) >= AVAHI_DOMAIN_NAME_MAX || !*t)

        return NULL;

    /* Subtype name */

    if (!(avahi_unescape_label(&t, label, sizeof(label))))

        return NULL;

    if (strlen(label) <= 2 || label[0] != '_')

        return NULL;

    if (!*t)

        return NULL;

    /* String "_sub" */

    if (!(avahi_unescape_label(&t, label, sizeof(label))))

        return NULL;

    if (strcasecmp(label, "_sub"))

        return NULL;

    if (!*t)

        return NULL;

    ret = t;

    /* Application name */

    if (!(avahi_unescape_label(&t, label, sizeof(label))))

        return NULL;

    if (strlen(label) <= 2 || label[0] != '_')

        return NULL;

    if (!*t)

        return NULL;

    /* _tcp or _udp boilerplate */

    if (!(avahi_unescape_label(&t, label, sizeof(label))))

        return NULL;

    if (strcasecmp(label, "_tcp") && strcasecmp(label, "_udp"))

        return NULL;

    if (*t)

        return NULL;

    return ret;

}

int avahi_is_valid_service_subtype(const char *t) {

    assert(t);

    return !!avahi_get_type_from_subtype(t);

}

int avahi_is_valid_domain_name(const char *t) {

    int is_first = 1;

    assert(t);

    if (strlen(t) >= AVAHI_DOMAIN_NAME_MAX)

        return 0;

    do {

        char label[AVAHI_LABEL_MAX];

        if (!(avahi_unescape_label(&t, label, sizeof(label))))

            return 0;

        /* Explicitly allow the root domain name */

        if (is_first && label[0] == 0 && *t == 0)

            return 1;

        is_first = 0;

        if (label[0] == 0)

            return 0;

    } while (*t);

    return 1;

}

int avahi_is_valid_service_name(const char *t) {

    assert(t);

    if (strlen(t) >= AVAHI_LABEL_MAX || !*t || !avahi_utf8_valid(t))

        return 0;

    return 1;

}

int avahi_is_valid_host_name(const char *t) {

    char label[AVAHI_LABEL_MAX];

    assert(t);

    if (strlen(t) >= AVAHI_DOMAIN_NAME_MAX || !*t)

        return 0;

    if (!(avahi_unescape_label(&t, label, sizeof(label))))

        return 0;

    if (strlen(label) < 1)

        return 0;

    if (*t)

        return 0;

    return 1;

}

unsigned avahi_domain_hash(const char *s) {

    unsigned hash = 0;

    while (*s) {

        char c[AVAHI_LABEL_MAX], *p, *r;

        r = avahi_unescape_label(&s, c, sizeof(c));

        assert(r);

        for (p = c; *p; p++)

            hash = 31 * hash + tolower(*p);

    }

    return hash;

}

int avahi_service_name_join(char *p, size_t size, const char *name, const char *type, const char *domain) {

    char escaped_name[AVAHI_LABEL_MAX*4];

    char normalized_type[AVAHI_DOMAIN_NAME_MAX];

    char normalized_domain[AVAHI_DOMAIN_NAME_MAX];

    assert(p);

    /* Validity checks */

    if ((name && !avahi_is_valid_service_name(name)))

        return AVAHI_ERR_INVALID_SERVICE_NAME;

    if (!avahi_is_valid_service_type_generic(type))

        return AVAHI_ERR_INVALID_SERVICE_TYPE;

    if (!avahi_is_valid_domain_name(domain))

        return AVAHI_ERR_INVALID_DOMAIN_NAME;

    /* Preparation */

    if (name) {

        size_t l = sizeof(escaped_name);

        char *e = escaped_name, *r;

        r = avahi_escape_label(name, strlen(name), &e, &l);

        assert(r);

    }

    if (!(avahi_normalize_name(type, normalized_type, sizeof(normalized_type))))

        return AVAHI_ERR_INVALID_SERVICE_TYPE;

    if (!(avahi_normalize_name(domain, normalized_domain, sizeof(normalized_domain))))

        return AVAHI_ERR_INVALID_DOMAIN_NAME;

    /* Concatenation */

    snprintf(p, size, "%s%s%s.%s", name ? escaped_name : "", name ? "." : "", normalized_type, normalized_domain);

    return AVAHI_OK;

}

#ifndef HAVE_STRLCPY

static size_t strlcpy(char *dest, const char *src, size_t n) {

    assert(dest);

    assert(src);

    if (n > 0) {

        strncpy(dest, src, n-1);

        dest[n-1] = 0;

    }

    return strlen(src);

}

#endif

int avahi_service_name_split(const char *p, char *name, size_t name_size, char *type, size_t type_size, char *domain, size_t domain_size) {

    enum {

        NAME,

        TYPE,

        DOMAIN

    } state;

    int type_empty = 1, domain_empty = 1;

    char *oname, *otype, *odomain;

    assert(p);

    assert(type);

    assert(type_size > 0);

    assert(domain);

    assert(domain_size > 0);

    oname = name;

    otype = type;

    odomain = domain;

    if (name) {

        assert(name_size > 0);

        *name = 0;

        state = NAME;

    } else

        state = TYPE;

    *type = *domain = 0;

    while (*p) {

        char buf[64];

        if (!(avahi_unescape_label(&p, buf, sizeof(buf))))

            return -1;

        switch (state) {

            case NAME:

                strlcpy(name, buf, name_size);

                state = TYPE;

                break;

            case TYPE:

                if (buf[0] == '_') {

                    if (!type_empty) {

                        if (!type_size)

                            return AVAHI_ERR_NO_MEMORY;

                        *(type++) = '.';

                        type_size --;

                    } else

                        type_empty = 0;

                    if (!(avahi_escape_label(buf, strlen(buf), &type, &type_size)))

                        return AVAHI_ERR_NO_MEMORY;

                    break;

                }

                state = DOMAIN;

                /* fall through */

            case DOMAIN:

                if (!domain_empty) {

                    if (!domain_size)

                        return AVAHI_ERR_NO_MEMORY;

                    *(domain++) = '.';

                    domain_size --;

                } else

                    domain_empty = 0;

                if (!(avahi_escape_label(buf, strlen(buf), &domain, &domain_size)))

                    return AVAHI_ERR_NO_MEMORY;

                break;

        }

    }

    if ((oname && !avahi_is_valid_service_name(oname)))

        return AVAHI_ERR_INVALID_SERVICE_NAME;

    if (!avahi_is_valid_service_type_strict(otype) && !avahi_is_valid_service_subtype(otype))

        return AVAHI_ERR_INVALID_SERVICE_TYPE;

    if (!avahi_is_valid_domain_name(odomain))

        return AVAHI_ERR_INVALID_DOMAIN_NAME;

    return 0;

}

int avahi_is_valid_fqdn(const char *t) {

    char label[AVAHI_LABEL_MAX];

    char normalized[AVAHI_DOMAIN_NAME_MAX];

    const char *k = t;

    AvahiAddress a;

    assert(t);

    if (strlen(t) >= AVAHI_DOMAIN_NAME_MAX)

        return 0;

    if (!avahi_is_valid_domain_name(t))

        return 0;

    /* Check if there are at least two labels*/

    if (!(avahi_unescape_label(&k, label, sizeof(label))))

        return 0;

    if (label[0] == 0 || !k)

        return 0;

    if (!(avahi_unescape_label(&k, label, sizeof(label))))

        return 0;

    if (label[0] == 0 || !k)

        return 0;

    /* Make sure that the name is not an IP address */

    if (!(avahi_normalize_name(t, normalized, sizeof(normalized))))

        return 0;

    if (avahi_address_parse(normalized, AVAHI_PROTO_UNSPEC, &a))

        return 0;

    return 1;

}