/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

/*

 * Copyright (C) 2019 by Sukchan Lee <acetcom@gmail.com>

 *

 * This file is part of Open5GS.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *   http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include "core-config-private.h"

#if HAVE_ARPA_INET_H

#include <arpa/inet.h>

#endif

#if HAVE_CTYPE_H

#include <ctype.h>

#endif

#if HAVE_IFADDRS_H

#include <ifaddrs.h>

#endif

#if HAVE_NETDB_H

#include <netdb.h>

#endif

#include "ogs-core.h"

#undef OGS_LOG_DOMAIN

#define OGS_LOG_DOMAIN __ogs_sock_domain

static bool ogs_sockaddr_compare(const ogs_sockaddr_t *a,

                                 const ogs_sockaddr_t *b,

                                 bool compare_port);

/* If you want to use getnameinfo,

 * you need to consider DNS query delay (about 10 seconds) */

#if 0

int ogs_getnameinfo(

    char *hostname, socklen_t hostname_len, ogs_sockaddr_t *addr, int flags)

{

    ogs_assert(hostname);

    ogs_assert(addr);

    return getnameinfo(&addr->sa, ogs_sockaddr_len(addr),

            hostname, hostname_len,

            NULL, 0, flags != 0 ? flags : NI_NAMEREQD);

}

#endif

int ogs_getaddrinfo(ogs_sockaddr_t **sa_list,

        int family, const char *hostname, uint16_t port, int flags)

{

    *sa_list = NULL;

    return ogs_addaddrinfo(sa_list, family, hostname, port, flags);

}

int ogs_freeaddrinfo(ogs_sockaddr_t *sa_list)

{

    ogs_sockaddr_t *next = NULL, *addr = NULL;

    addr = sa_list;

    while (addr) {

        next = addr->next;

        if (addr->hostname)

            ogs_free(addr->hostname);

        ogs_free(addr);

        addr = next;

    }

    return OGS_OK;

}

int ogs_addaddrinfo(ogs_sockaddr_t **sa_list,

        int family, const char *hostname, uint16_t port, int flags)

{

    int rc;

    char service[NI_MAXSERV];

    struct addrinfo hints, *ai, *ai_list;

    ogs_sockaddr_t *prev;

    char buf[OGS_ADDRSTRLEN];

    ogs_assert(sa_list);

    memset(&hints, 0, sizeof(hints));

    hints.ai_family = family;

    hints.ai_socktype = SOCK_STREAM;

    hints.ai_flags = flags;

    ogs_snprintf(service, sizeof(service), "%u", port);

    rc = getaddrinfo(hostname, service, &hints, &ai_list);

    if (rc != 0) {

        ogs_log_message(OGS_LOG_ERROR, ogs_socket_errno,

                "getaddrinfo(%d:%s:%d:0x%x) failed",

                family, hostname, port, flags);

        return OGS_ERROR;

    }

    prev = NULL;

    if (*sa_list) {

        prev = *sa_list;

        while(prev->next) prev = prev->next;

    }

    for (ai = ai_list; ai; ai = ai->ai_next) {

        ogs_sockaddr_t *new, tmp;

        if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)

            continue;

        new = ogs_calloc(1, sizeof(ogs_sockaddr_t));

        if (!new) {

            ogs_error("ogs_calloc() failed");

            return OGS_ERROR;

        }

        memcpy(&new->sa, ai->ai_addr, ai->ai_addrlen);

        new->ogs_sin_port = htobe16(port);

        if (hostname) {

            if (ogs_inet_pton(ai->ai_family, hostname, &tmp) == OGS_OK) {

                /* It's a valid IP address */

                ogs_debug("addr:%s, port:%d", OGS_ADDR(new, buf), port);

            } else {

                /* INVALID IP address! We assume it is a hostname */

                new->hostname = ogs_strdup(hostname);

                ogs_assert(new->hostname);

                ogs_debug("name:%s, port:%d", new->hostname, port);

            }

        }

        if (!prev)

            *sa_list = new;

        else

            prev->next = new;

        prev = new;

    }

    freeaddrinfo(ai_list);

    if (prev == NULL) {

        ogs_log_message(OGS_LOG_ERROR, ogs_socket_errno,

                "ogs_getaddrinfo(%d:%s:%d:%d) failed",

                family, hostname, port, flags);

        return OGS_ERROR;

    }

    return OGS_OK;

}

int ogs_filteraddrinfo(ogs_sockaddr_t **sa_list, int family)

{

    ogs_sockaddr_t *addr = NULL, *prev = NULL, *next = NULL;

    ogs_assert(sa_list);

    prev = NULL;

    addr = *sa_list;

    while (addr) {

        next = addr->next;

        if (addr->ogs_sa_family != family) {

            if (prev)

                prev->next = addr->next;

            else

                *sa_list = addr->next;

            if (addr->hostname)

                ogs_free(addr->hostname);

            ogs_free(addr);

        } else {

            prev = addr;

        }

        addr = next;

    }

    return OGS_OK;

}

int ogs_copyaddrinfo(ogs_sockaddr_t **dst, const ogs_sockaddr_t *src)

{

    ogs_sockaddr_t *d;

    const ogs_sockaddr_t *s;

    for (*dst = d = NULL, s = src; s; s = s->next) {

        if (!d) {

            *dst = d = ogs_memdup(s, sizeof *s);

            if (!(*dst)) {

                ogs_error("ogs_memdup() failed");

                return OGS_ERROR;

            }

        } else {

            d = d->next = ogs_memdup(s, sizeof *s);

            if (!d) {

                ogs_error("ogs_memdup() failed");

                return OGS_ERROR;

            }

        }

        if (s->hostname) {

            if (s == src || s->hostname != src->hostname) {

                d->hostname = ogs_strdup(s->hostname);

                if (!d->hostname) {

                    ogs_error("ogs_memdup() failed");

                    return OGS_ERROR;

                }

            } else {

                d->hostname = (*dst)->hostname;

            }

        }

    }

    return OGS_OK;

}

int ogs_sortaddrinfo(ogs_sockaddr_t **sa_list, int family)

{

    ogs_sockaddr_t *head = NULL, *addr = NULL, *new = NULL, *old = NULL;

    ogs_assert(sa_list);

    old = *sa_list;

    while (old) {

        addr = old;

        old = old->next;

        if (head == NULL || addr->ogs_sa_family == family) {

            addr->next = head;

            head = addr;

        } else {

            new = head;

            while(new->next != NULL && new->next->ogs_sa_family != family) {

                new = new->next;

            }

            addr->next = new->next;

            new->next = addr;

        }

    }

    *sa_list = head;

    return OGS_OK;

}

/*--------------------------------------------------------------------------

 * Merge a single node if not already in "dest" list

 *--------------------------------------------------------------------------

 */

void ogs_merge_single_addrinfo(

        ogs_sockaddr_t **dest, const ogs_sockaddr_t *item)

{

    ogs_sockaddr_t *p;

    ogs_sockaddr_t *new_sa;

    ogs_assert(dest);

    ogs_assert(item);

    p = *dest;

    while (p) {

        if (ogs_sockaddr_is_equal(p, item)) {

            /* Already exists */

            return;

        }

        p = p->next;

    }

    new_sa = (ogs_sockaddr_t *)ogs_malloc(sizeof(*new_sa));

    ogs_assert(new_sa);

    memcpy(new_sa, item, sizeof(*new_sa));

    if (item->hostname) {

        new_sa->hostname = ogs_strdup(item->hostname);

        ogs_assert(new_sa->hostname);

    }

    new_sa->next = NULL;

    if (!(*dest)) {

        *dest = new_sa;

    } else {

        p = *dest;

        while (p->next)

            p = p->next;

        p->next = new_sa;

    }

}

/*--------------------------------------------------------------------------

 * Merge an entire src list into dest

 *--------------------------------------------------------------------------

 */

void ogs_merge_addrinfo(ogs_sockaddr_t **dest, const ogs_sockaddr_t *src)

{

    const ogs_sockaddr_t *cur;

    cur = src;

    while (cur) {

        ogs_merge_single_addrinfo(dest, cur);

        cur = cur->next;

    }

}

ogs_sockaddr_t *ogs_link_local_addr(const char *dev, const ogs_sockaddr_t *sa)

{

#if defined(HAVE_GETIFADDRS)

    struct ifaddrs *iflist, *cur;

    int rc;

    rc = getifaddrs(&iflist);

    if (rc != 0) {

        ogs_log_message(OGS_LOG_ERROR, ogs_socket_errno, "getifaddrs failed");

        return NULL;

    }

    for (cur = iflist; cur != NULL; cur = cur->ifa_next) {

        ogs_sockaddr_t *ifa_addr = NULL;

        ogs_sockaddr_t *addr = NULL;

        ifa_addr = (ogs_sockaddr_t *)cur->ifa_addr;

        if (ifa_addr == NULL) /* may happen with ppp interfaces */

            continue;

        if (ifa_addr->ogs_sa_family == AF_INET)

            continue;

        if (!IN6_IS_ADDR_LINKLOCAL(&ifa_addr->sin6.sin6_addr))

            continue;

        if (dev && strcmp(dev, cur->ifa_name) != 0)

            continue;

        if (sa && memcmp(&sa->sin6.sin6_addr,

                &ifa_addr->sin6.sin6_addr, sizeof(struct in6_addr)) != 0)

            continue;

        addr = ogs_calloc(1, sizeof(ogs_sockaddr_t));

        if (!addr) {

            ogs_error("ogs_calloc() failed");

            return NULL;

        }

        ogs_assert(addr);

        memcpy(&addr->sa, cur->ifa_addr, ogs_sockaddr_len(cur->ifa_addr));

        freeifaddrs(iflist);

        return addr;

    }

    freeifaddrs(iflist);

#endif

    return NULL;

}

ogs_sockaddr_t *ogs_link_local_addr_by_dev(const char *dev)

{

    ogs_assert(dev);

    return ogs_link_local_addr(dev, NULL);

}

ogs_sockaddr_t *ogs_link_local_addr_by_sa(const ogs_sockaddr_t *sa)

{

    ogs_assert(sa);

    return ogs_link_local_addr(NULL, sa);

}

int ogs_filter_ip_version(ogs_sockaddr_t **addr,

        int no_ipv4, int no_ipv6, int prefer_ipv4)

{

    int rv;

    if (no_ipv4 == 1) {

        rv = ogs_filteraddrinfo(addr, AF_INET6);

        ogs_assert(rv == OGS_OK);

    }

    if (no_ipv6 == 1) {

        rv = ogs_filteraddrinfo(addr, AF_INET);

        ogs_assert(rv == OGS_OK);

    }

    if (prefer_ipv4 == 1) {

        rv = ogs_sortaddrinfo(addr, AF_INET);

        ogs_assert(rv == OGS_OK);

    } else {

        rv = ogs_sortaddrinfo(addr, AF_INET6);

        ogs_assert(rv == OGS_OK);

    }

    return OGS_OK;

}

const char *ogs_inet_ntop(void *sa, char *buf, int buflen)

{

    int family;

    ogs_sockaddr_t *sockaddr = NULL;

    sockaddr = sa;

    ogs_assert(sockaddr);

    ogs_assert(buf);

    ogs_assert(buflen >= OGS_ADDRSTRLEN);

    family = sockaddr->ogs_sa_family;

    switch (family) {

    case AF_INET:

        return inet_ntop(family, &sockaddr->sin.sin_addr, buf,

                INET_ADDRSTRLEN);

    case AF_INET6:

        return inet_ntop(family, &sockaddr->sin6.sin6_addr, buf,

                INET6_ADDRSTRLEN);

    default:

        ogs_fatal("Unknown family(%d)", family);

        ogs_abort();

        return NULL;

    }

}

int ogs_inet_pton(int family, const char *src, void *sa)

{

    ogs_sockaddr_t *dst = NULL;

    ogs_assert(src);

    dst = sa;

    ogs_assert(dst);

    dst->ogs_sa_family = family;

    switch(family) {

    case AF_INET:

        return inet_pton(family, src, &dst->sin.sin_addr) == 1 ?

            OGS_OK : OGS_ERROR;

    case AF_INET6:

        return inet_pton(family, src, &dst->sin6.sin6_addr) == 1 ?

             OGS_OK : OGS_ERROR;

    default:

        ogs_fatal("Unknown family(%d)", family);

        ogs_abort();

        return OGS_ERROR;

    }

}

socklen_t ogs_sockaddr_len(const void *sa)

{

    const ogs_sockaddr_t *sockaddr = sa;

    ogs_assert(sa);

    switch(sockaddr->ogs_sa_family) {

    case AF_INET:

        return sizeof(struct sockaddr_in);

    case AF_INET6:

        return sizeof(struct sockaddr_in6);

    default:

        ogs_fatal("Unknown family(%d)", sockaddr->ogs_sa_family);

        ogs_abort();

        return OGS_ERROR;

    }

}

/*

 * Helper function to compare two addresses.

 * If compare_port is true, compare both port and address.

 * Otherwise, compare address only.

 */

static bool ogs_sockaddr_compare(const ogs_sockaddr_t *a,

                                 const ogs_sockaddr_t *b,

                                 bool compare_port)

{

    ogs_assert(a);

    ogs_assert(b);

    if (a->ogs_sa_family != b->ogs_sa_family)

        return false;

    switch (a->ogs_sa_family) {

    case AF_INET:

        if (compare_port && (a->sin.sin_port != b->sin.sin_port))

            return false;

        if (memcmp(&a->sin.sin_addr, &b->sin.sin_addr,

                   sizeof(struct in_addr)) != 0)

            return false;

        return true;

    case AF_INET6:

        if (compare_port && (a->sin6.sin6_port != b->sin6.sin6_port))

            return false;

        if (memcmp(&a->sin6.sin6_addr, &b->sin6.sin6_addr,

                   sizeof(struct in6_addr)) != 0)

            return false;

        return true;

    default:

        ogs_error("Unexpected address family %u", a->ogs_sa_family);

        ogs_abort();

        return false; /* Defensive return */

    }

}

/* Compare addresses including port */

bool ogs_sockaddr_is_equal(const void *p, const void *q)

{

    const ogs_sockaddr_t *a = (const ogs_sockaddr_t *)p;

    const ogs_sockaddr_t *b = (const ogs_sockaddr_t *)q;

    return ogs_sockaddr_compare(a, b, true);

}

/* Compare addresses without considering port */

bool ogs_sockaddr_is_equal_addr(const void *p, const void *q)

{

    const ogs_sockaddr_t *a = (const ogs_sockaddr_t *)p;

    const ogs_sockaddr_t *b = (const ogs_sockaddr_t *)q;

    return ogs_sockaddr_compare(a, b, false);

}

bool ogs_sockaddr_check_any_match(

        ogs_sockaddr_t *base,

        ogs_sockaddr_t *list, const ogs_sockaddr_t *single, bool compare_port)

{

    ogs_sockaddr_t *p = NULL;

    while (list) {

        p = base;

        while (p) {

            if (ogs_sockaddr_compare(p, list, compare_port) == true)

                return true;

            p = p->next;

        }

        list = list->next;

    }

    if (single) {

        p = base;

        while (p) {

            if (ogs_sockaddr_compare(p, single, compare_port) == true)

                return true;

            p = p->next;

        }

    }

    return false;

}

static int parse_network(ogs_ipsubnet_t *ipsub, const char *network)

{

    /* legacy syntax for ip addrs: a.b.c. ==> a.b.c.0/24 for example */

    int shift;

    char *s, *t;

    int octet;

    char buf[sizeof "255.255.255.255"];

    if (strlen(network) < sizeof buf)

        strcpy(buf, network);

    else

        return OGS_ERROR;

    /* parse components */

    s = buf;

    ipsub->sub[0] = 0;

    ipsub->mask[0] = 0;

    shift = 24;

    while (*s) {

        t = s;

        if (!isdigit(*t))

            return OGS_ERROR;

        while (isdigit(*t))

            ++t;

        if (*t == '.')

            *t++ = 0;

        else if (*t)

            return OGS_ERROR;

        if (shift < 0)

            return OGS_ERROR;

        octet = atoi(s);

        if (octet < 0 || octet > 255)

            return OGS_ERROR;

        ipsub->sub[0] |= octet << shift;

        ipsub->mask[0] |= 0xFFUL << shift;

        s = t;

        shift -= 8;

    }

    ipsub->sub[0] = be32toh(ipsub->sub[0]);

    ipsub->mask[0] = be32toh(ipsub->mask[0]);

    ipsub->family = AF_INET;

    return OGS_OK;

}

/* return values:

 * CORE_EINVAL     not an IP address; caller should see

 *                 if it is something else

 * CORE_BADIP      IP address portion is is not valid

 * CORE_BADMASK    mask portion is not valid

 */

static int parse_ip(

        ogs_ipsubnet_t *ipsub, const char *ipstr, int network_allowed)

{

    /* supported flavors of IP:

     *

     * . IPv6 numeric address string (e.g., "fe80::1")

     *

     *   IMPORTANT: Don't store IPv4-mapped IPv6 address as an IPv6 address.

     *

     * . IPv4 numeric address string (e.g., "127.0.0.1")

     *

     * . IPv4 network string (e.g., "9.67")

     *

     *   IMPORTANT: This network form is only allowed if network_allowed is on.

     */

    int rc;

    rc = inet_pton(AF_INET6, ipstr, ipsub->sub);

    if (rc == 1) {

        if (IN6_IS_ADDR_V4MAPPED((struct in6_addr *)ipsub->sub)) {

            /* ipsubnet_test() assumes that we don't create IPv4-mapped IPv6

             * addresses; this of course forces the user to specify

             * IPv4 addresses in a.b.c.d style instead of ::ffff:a.b.c.d style.

             */

            ogs_error("Cannot support IPv4-mapped IPv6: "

                    "Use IPv4 address in a.b.c.d style "

                    "instead of ::ffff:a.b.c.d style");

            return OGS_ERROR;

        }

        ipsub->family = AF_INET6;

    } else {

        rc = inet_pton(AF_INET, ipstr, ipsub->sub);

        if (rc == 1) {

            ipsub->family = AF_INET;

        }

    }

    if (rc != 1) {

        if (network_allowed)

            return parse_network(ipsub, ipstr);

        else

            return OGS_ERROR;

    }

    return OGS_OK;

}

static int looks_like_ip(const char *ipstr)

{

    if (strlen(ipstr) == 0)

        return 0;

    if (strchr(ipstr, ':')) {

        /* definitely not a hostname;

         * assume it is intended to be an IPv6 address */

        return 1;

    }

    /* simple IPv4 address string check */

    while ((*ipstr == '.') || isdigit(*ipstr))

        ipstr++;

    return (*ipstr == '\0');

}

static void fix_subnet(ogs_ipsubnet_t *ipsub)

{

    /* in case caller specified more bits in network address than are

     * valid according to the mask, turn off the extra bits

     */

    int i;

    for (i = 0; i < sizeof ipsub->mask / sizeof(int32_t); i++)

        ipsub->sub[i] &= ipsub->mask[i];

}

/* be sure not to store any IPv4 address as a v4-mapped IPv6 address */

int ogs_ipsubnet(ogs_ipsubnet_t *ipsub,

        const char *ipstr, const char *mask_or_numbits)

{

    int rv;

    char *endptr;

    long bits, maxbits = 32;

    ogs_assert(ipsub);

    ogs_assert(ipstr);

    /* filter out stuff which doesn't look remotely like an IP address;

     * this helps callers like mod_access which have a syntax allowing

     * hostname or IP address;

     * CORE_EINVAL tells the caller that it was probably not intended

     * to be an IP address

     */

    if (!looks_like_ip(ipstr)) {

        ogs_error("looks_like_ip(%s, %s) failed", ipstr, mask_or_numbits);

        return OGS_ERROR;

    }

    /* assume ipstr is an individual IP address, not a subnet */

    memset(ipsub->mask, 0xFF, sizeof ipsub->mask);

    rv = parse_ip(ipsub, ipstr, mask_or_numbits == NULL);

    if (rv != OGS_OK) {

        ogs_error("parse_ip(%s, %s) failed", ipstr, mask_or_numbits);

        return rv;

    }

    if (mask_or_numbits) {

        if (ipsub->family == AF_INET6) {

            maxbits = 128;

        }

        bits = strtol(mask_or_numbits, &endptr, 10);

        if (*endptr == '\0' && bits > 0 && bits <= maxbits) {

            /* valid num-bits string; fill in mask appropriately */

            int cur_entry = 0;

            int32_t cur_bit_value;

            memset(ipsub->mask, 0, sizeof ipsub->mask);

            while (bits > 32) {

                ipsub->mask[cur_entry] = 0xFFFFFFFF; /* all 32 bits */

                bits -= 32;

                ++cur_entry;

            }

            cur_bit_value = 0x80000000;

            while (bits) {

                ipsub->mask[cur_entry] |= cur_bit_value;

                --bits;

                cur_bit_value /= 2;

            }

            ipsub->mask[cur_entry] = htobe32(ipsub->mask[cur_entry]);

        }

        else if (inet_pton(AF_INET, mask_or_numbits, ipsub->mask) == 1 &&

            ipsub->family == AF_INET) {

            /* valid IPv4 netmask */

        } else {

            ogs_error("Bad netmask %s", mask_or_numbits);

            return OGS_ERROR;

        }

    }

    fix_subnet(ipsub);

    return OGS_OK;

}

char *ogs_gethostname(ogs_sockaddr_t *addr)

{

    return addr->hostname;

}

char *ogs_ipstrdup(ogs_sockaddr_t *addr)

{

    char buf[OGS_ADDRSTRLEN + 1];

    ogs_assert(addr);

    memset(buf, 0, sizeof(buf));

    OGS_ADDR(addr, buf);

    return ogs_strdup(buf);

}

char *ogs_sockaddr_to_string_static(ogs_sockaddr_t *sa_list)

{

    static char dumpstr[OGS_HUGE_LEN] = { 0, };

    char *p, *last;

    ogs_sockaddr_t *addr = NULL;

    last = dumpstr + OGS_HUGE_LEN;

    p = dumpstr;

    addr = (ogs_sockaddr_t *)sa_list;

    while (addr) {

        char buf[OGS_ADDRSTRLEN];

        p = ogs_slprintf(p, last, "[%s]:%d ",

                OGS_ADDR(addr, buf), OGS_PORT(addr));

        addr = addr->next;

    }

    if (p > dumpstr) {

        /* If there is more than one addr, remove the last character */

        *(p-1) = 0;

        return dumpstr;

    }

    /* No address */

    return NULL;

}