/*
 * Copyright (c) 2015 Carsten Larsen
 * Copyright (c) 2001, 02  Motoyuki Kasahara
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``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 PROJECT OR CONTRIBUTORS 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.
 */

/*
 * This program provides getaddrinfo() and getnameinfo() described in
 * RFC2133, 2553 and 3493.  These functions are mainly used for IPv6
 * application to resolve hostname or address.
 *
 * This program is designed to be working on traditional IPv4 systems
 * which don't have those functions.  Therefore, this implementation
 * supports IPv4 only.
 *
 * This program is useful for application which should support both IPv6
 * and traditional IPv4 systems.  Use genuine getaddrinfo() and getnameinfo()
 * provided by system if the system supports IPv6.  Otherwise, use this
 * implementation.
 *
 * This program also provides freeaddrinfo() and gai_strerror().
 *
 * Restriction:
 *   getaddrinfo() and getnameinfo() of this program are NOT thread
 *   safe, unless the cpp macro ENABLE_PTHREAD is defined.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory.h>
#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include "ntimed_platform.h"
#include "ntimed.h"
#include "net_getaddrinfo.h"

#ifdef ENABLE_PTHREAD
#include <pthread.h>
#endif

#ifdef ENABLE_NLS
#include <libintl.h>
#endif

#ifdef ENABLE_NLS
#define _(string) gettext(string)
#ifdef gettext_noop
#define N_(string) gettext_noop(string)
#else
#define N_(string) (string)
#endif
#else
#define gettext(string) (string)
#define _(string) (string)
#define N_(string) (string)
#endif

/*
 * Error messages for gai_strerror().
 */
static char *eai_errlist[] = {
    N_("Success"),

    /* EAI_ADDRFAMILY */
    N_("Address family for hostname not supported"),

    /* EAI_AGAIN */
    N_("Temporary failure in name resolution"),

    /* EAI_BADFLAGS */
    N_("Invalid value for ai_flags"),

    /* EAI_FAIL */
    N_("Non-recoverable failure in name resolution"),

    /* EAI_FAMILY */
    N_("ai_family not supported"),

    /* EAI_MEMORY */
    N_("Memory allocation failure"),

    /* EAI_NONAME */
    N_("hostname nor servname provided, or not known"),

    /* EAI_OVERFLOW */
    N_("An argument buffer overflowed"),

    /* EAI_SERVICE */
    N_("servname not supported for ai_socktype"),

    /* EAI_SOCKTYPE */
    N_("ai_socktype not supported"),

    /* EAI_SYSTEM */
    N_("System error returned in errno")
};

/*
 * Default hints for getaddrinfo().
 */
static struct addrinfo default_hints = {
    0, PF_UNSPEC, 0, 0, 0, NULL, NULL, NULL
};

/*
 * Mutex.
 */
#ifdef ENABLE_PTHREAD
static pthread_mutex_t gai_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif

/*
 * Declaration of static functions.
 */
#ifdef __STDC__
static int is_integer(const char *);
static int is_address(const char *);
static int itoa_length(int);
#else
static int is_integer();
static int is_address();
static int itoa_length();
#endif

/*
 * gai_strerror().
 */
const char *
gai_strerror(ecode)
int ecode;
{
    if (ecode < 0 || ecode > EAI_SYSTEM)
        return _("Unknown error");

    return gettext(eai_errlist[ecode]);
}

/*
 * freeaddrinfo().
 */
void
freeaddrinfo(ai)
struct addrinfo *ai;
{
    struct addrinfo *next_ai;

    while (ai != NULL) {
        if (ai->ai_canonname != NULL)
            free(ai->ai_canonname);
        if (ai->ai_addr != NULL)
            free(ai->ai_addr);
        next_ai = ai->ai_next;
        free(ai);
        ai = next_ai;
    }
}

/*
 * Return 1 if the string `s' represents an integer.
 */
static int
is_integer(s)
const char *s;
{
    if (*s == '-' || *s == '+')
        s++;
    if (*s < '0' || '9' < *s)
        return 0;

    s++;
    while ('0' <= *s && *s <= '9')
        s++;

    return (*s == '\0');
}

/*
 * Return 1 if the string `s' represents an IPv4 address.
 * Unlike inet_addr(), it doesn't permit malformed nortation such
 * as "192.168".
 */
static int
is_address(s)
const char *s;
{
    const static char delimiters[] = {'.', '.', '.', '\0'};
    int i, j;
    int octet;

    for (i = 0; i < 4; i++) {
        if (*s == '0' && *(s + 1) != delimiters[i])
            return 0;
        for (j = 0, octet = 0; '0' <= *s && *s <= '9' && j < 3; s++, j++)
            octet = octet * 10 + (*s - '0');
        if (j == 0 || octet > 255 || *s != delimiters[i])
            return 0;
        s++;
    }

    return 1;
}

/*
 * Calcurate length of the string `s', where `s' is set by
 * sprintf(s, "%d", n).
 */
static int
itoa_length(n)
int n;
{
    int result = 1;

    if (n < 0) {
        n = -n;
        result++;
    }

    while (n >= 10) {
        result++;
        n /= 10;
    }

    return result;
}

/*
 * getaddrinfo().
 */
int
getaddrinfo(nodename, servname, hints, res)
const char *nodename;
const char *servname;
const struct addrinfo *hints;
struct addrinfo **res;
{
    struct addrinfo *head_res = NULL;
    struct addrinfo *tail_res = NULL;
    struct addrinfo *new_res;
    struct sockaddr_in *sa_in;
    struct in_addr **addr_list;
    struct in_addr *addr_list_buf[2];
    struct in_addr addr_buf;
    struct in_addr **ap;
    struct servent *servent;
    struct hostent *hostent;
    const char *canonname = NULL;
    in_port_t port;
    int saved_h_errno;
    int result = 0;

#ifdef ENABLE_PTHREAD
    pthread_mutex_lock(&gai_mutex);
#endif

    saved_h_errno = h_errno;

    if (nodename == NULL && servname == NULL) {
        result = EAI_NONAME;
        goto end;
    }

    if (hints != NULL) {
        if (hints->ai_family != PF_INET && hints->ai_family != PF_UNSPEC) {
            result = EAI_FAMILY;
            goto end;
        }
        if (hints->ai_socktype != SOCK_DGRAM
                && hints->ai_socktype != SOCK_STREAM
                && hints->ai_socktype != 0) {
            result = EAI_SOCKTYPE;
            goto end;
        }
    } else {
        hints = &default_hints;
    }

    if (servname != NULL) {
        if (is_integer(servname))
            port = htons(atoi(servname));
        else  {
            if (hints->ai_flags & AI_NUMERICSERV) {
                result = EAI_NONAME;
                goto end;
            }

            if (hints->ai_socktype == SOCK_DGRAM)
                servent = getservbyname((char*)servname, (char*)"udp");
            else if (hints->ai_socktype == SOCK_STREAM)
                servent = getservbyname((char*)servname, (char*)"tcp");
            else if (hints->ai_socktype == 0)
                servent = getservbyname((char*)servname, (char*)"tcp");
            else {
                result = EAI_SOCKTYPE;
                goto end;
            }

            if (servent == NULL) {
                result = EAI_SERVICE;
                goto end;
            }
            port = servent->s_port;
        }
    } else {
        port = htons(0);
    }

    if (nodename != NULL) {
        if (is_address(nodename)) {
            addr_buf.s_addr = inet_addr(nodename);
            addr_list_buf[0] = &addr_buf;
            addr_list_buf[1] = NULL;
            addr_list = addr_list_buf;

            if (hints->ai_flags & AI_CANONNAME
                    && !(hints->ai_flags & AI_NUMERICHOST)) {
                hostent = gethostbyaddr((char *)&addr_buf,
                                        sizeof(struct in_addr), AF_INET);
                if (hostent != NULL)
                    canonname = hostent->h_name;
                else
                    canonname = nodename;
            }
        } else {
            if (hints->ai_flags & AI_NUMERICHOST) {
                result = EAI_NONAME;
                goto end;
            }

            hostent = gethostbyname(nodename);
            if (hostent == NULL) {
                switch (h_errno) {
                case HOST_NOT_FOUND:
                case NO_DATA:
                    result = EAI_NONAME;
                    goto end;
                case TRY_AGAIN:
                    result = EAI_AGAIN;
                    goto end;
                default:
                    result = EAI_FAIL;
                    goto end;
                }
            }
            addr_list = (struct in_addr **)hostent->h_addr_list;

            if (hints->ai_flags & AI_CANONNAME)
                canonname = hostent->h_name;
        }
    } else {
        if (hints->ai_flags & AI_PASSIVE)
            addr_buf.s_addr = htonl(INADDR_ANY);
        else
            addr_buf.s_addr = htonl(0x7F000001);
        addr_list_buf[0] = &addr_buf;
        addr_list_buf[1] = NULL;
        addr_list = addr_list_buf;
    }

    for (ap = addr_list; *ap != NULL; ap++) {
        new_res = (struct addrinfo *)malloc(sizeof(struct addrinfo));
        if (new_res == NULL) {
            if (head_res != NULL)
                freeaddrinfo(head_res);
            result = EAI_MEMORY;
            goto end;
        }

        new_res->ai_family = PF_INET;
        new_res->ai_socktype = hints->ai_socktype;
        new_res->ai_protocol = hints->ai_protocol;
        new_res->ai_addr = NULL;
        new_res->ai_addrlen = sizeof(struct sockaddr_in);
        new_res->ai_canonname = NULL;
        new_res->ai_next = NULL;

        new_res->ai_addr = (struct sockaddr *)
                           malloc(sizeof(struct sockaddr_in));
        if (new_res->ai_addr == NULL) {
            free(new_res);
            if (head_res != NULL)
                freeaddrinfo(head_res);
            result = EAI_MEMORY;
            goto end;
        }

        sa_in = (struct sockaddr_in *)new_res->ai_addr;
        memset(sa_in, 0, sizeof(struct sockaddr_in));
        sa_in->sin_family = PF_INET;
        sa_in->sin_port = port;
        memcpy(&sa_in->sin_addr, *ap, sizeof(struct in_addr));

        if (head_res == NULL)
            head_res = new_res;
        else
            tail_res->ai_next = new_res;
        tail_res = new_res;
    }

    if (canonname != NULL && head_res != NULL) {
        head_res->ai_canonname = (char *)malloc(strlen(canonname) + 1);
        if (head_res->ai_canonname != NULL)
            strcpy(head_res->ai_canonname, canonname);
    }

    *res = head_res;

end:
    h_errno = saved_h_errno;
#ifdef ENABLE_PTHREAD
    pthread_mutex_unlock(&gai_mutex);
#endif
    return result;
}

int getnameinfo(const struct sockaddr *sa, socklen_t salen, char *node, socklen_t nodelen, char *serv, socklen_t servlen, int flags) {

    const struct sockaddr_in *sa_in = (const struct sockaddr_in *)sa;
    struct hostent *hostent;
    struct servent *servent;
    char *ntoa_address;
    int saved_h_errno;
    int result = 0;

#ifdef ENABLE_PTHREAD
    pthread_mutex_lock(&gai_mutex);
#endif

    saved_h_errno = h_errno;

    if (sa_in->sin_family != PF_INET) {
        result = EAI_FAMILY;
        goto end;
    } else if (node == NULL && serv == NULL) {
        result = EAI_NONAME;
        goto end;
    }

    if (serv != NULL && servlen > 0) {
        if (flags & NI_NUMERICSERV)
            servent = NULL;
        else if (flags & NI_DGRAM)
            servent = getservbyport(sa_in->sin_port, "udp");
        else
            servent = getservbyport(sa_in->sin_port, "tcp");

        if (servent != NULL) {
            if (servlen <= strlen(servent->s_name)) {
                result = EAI_OVERFLOW;
                goto end;
            }
            strcpy(serv, servent->s_name);
        } else {
            if (servlen <= itoa_length(ntohs(sa_in->sin_port))) {
                result = EAI_OVERFLOW;
                goto end;
            }
            sprintf(serv, "%d", ntohs(sa_in->sin_port));
        }
    }

    if (node != NULL && nodelen > 0) {
        if (flags & NI_NUMERICHOST)
            hostent = NULL;
        else {
            hostent = gethostbyaddr((char *)&sa_in->sin_addr,
                                    sizeof(struct in_addr), AF_INET);
        }
        if (hostent != NULL) {
            if (nodelen <= strlen(hostent->h_name)) {
                result = EAI_OVERFLOW;
                goto end;
            }
            strcpy(node, hostent->h_name);
        } else {
            if (flags & NI_NAMEREQD) {
                result = EAI_NONAME;
                goto end;
            }
#ifndef AOS3
            ntoa_address = inet_ntoa(sa_in->sin_addr);
#else
            ntoa_address = inet_ntoa((LONG)sa_in->sin_addr.s_addr);
#endif
            if (nodelen <= strlen(ntoa_address)) {
                result = EAI_OVERFLOW;
                goto end;
            }
            strcpy(node, ntoa_address);
        }

    }

end:
    h_errno = saved_h_errno;
#ifdef ENABLE_PTHREAD
    pthread_mutex_unlock(&gai_mutex);
#endif
    return result;
}