/*

 * Copyright (C) 2025 by Sukchan Lee <acetcom@gmail.com>

 *

 * This file is part of Open5GS.

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Affero General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

#include "ogs-pfcp.h"

/*

 * Requirements of Node ID:

 * NONE      : Node ID must not be present

 * OPTIONAL  : Node ID may or may not be present

 * MANDATORY : Node ID must be present

 */

#define OGS_PFCP_NODE_ID_NONE      0

#define OGS_PFCP_NODE_ID_OPTIONAL  1

#define OGS_PFCP_NODE_ID_MANDATORY 2

/*

 * This function extracts the PFCP Node ID from the given PFCP message.

 * It determines the Node ID field location and requirement based on

 * the message type. Then it validates presence and copies data into

 * 'node_id'. If Node ID is not consistent with the requirement, an

 * error status is returned.

 */

ogs_pfcp_status_e

ogs_pfcp_extract_node_id(ogs_pfcp_message_t *message,

                         ogs_pfcp_node_id_t *node_id)

{

    /* For C89 compliance, all variables are declared upfront. */

    ogs_pfcp_tlv_node_id_t *tlv_node_id = NULL;

    int requirement = OGS_PFCP_NODE_ID_NONE;

    ogs_pfcp_status_e status = OGS_PFCP_STATUS_SUCCESS;

    /* Validate input pointers */

    ogs_assert(message);

    ogs_assert(node_id);

    /* Initialize the output structure */

    memset(node_id, 0, sizeof(*node_id));

    /* Determine the location of node_id TLV and requirement */

    switch (message->h.type) {

    case OGS_PFCP_PFD_MANAGEMENT_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_pfd_management_request.node_id;

        requirement = OGS_PFCP_NODE_ID_OPTIONAL;

        break;

    case OGS_PFCP_PFD_MANAGEMENT_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_pfd_management_response.node_id;

        requirement = OGS_PFCP_NODE_ID_OPTIONAL;

        break;

    case OGS_PFCP_ASSOCIATION_SETUP_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_association_setup_request.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_ASSOCIATION_SETUP_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_association_setup_response.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_ASSOCIATION_UPDATE_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_association_update_request.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_ASSOCIATION_UPDATE_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_association_update_response.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_ASSOCIATION_RELEASE_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_association_release_request.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_ASSOCIATION_RELEASE_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_association_release_response.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_NODE_REPORT_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_node_report_request.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_NODE_REPORT_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_node_report_response.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_SESSION_SET_DELETION_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_session_set_deletion_request.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_SESSION_SET_DELETION_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_session_set_deletion_response.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_SESSION_SET_MODIFICATION_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_session_set_modification_request.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_SESSION_SET_MODIFICATION_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_session_set_modification_response.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_SESSION_ESTABLISHMENT_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_session_establishment_request.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_SESSION_ESTABLISHMENT_RESPONSE_TYPE:

        tlv_node_id = &message->pfcp_session_establishment_response.node_id;

        requirement = OGS_PFCP_NODE_ID_MANDATORY;

        break;

    case OGS_PFCP_SESSION_MODIFICATION_REQUEST_TYPE:

        tlv_node_id = &message->pfcp_session_modification_request.node_id;

        requirement = OGS_PFCP_NODE_ID_OPTIONAL;

        break;

    /* Add other message types with node_id here as needed */

    case OGS_PFCP_HEARTBEAT_REQUEST_TYPE:

    case OGS_PFCP_HEARTBEAT_RESPONSE_TYPE:

    case OGS_PFCP_VERSION_NOT_SUPPORTED_RESPONSE_TYPE:

    case OGS_PFCP_SESSION_MODIFICATION_RESPONSE_TYPE:

    case OGS_PFCP_SESSION_DELETION_REQUEST_TYPE:

    case OGS_PFCP_SESSION_DELETION_RESPONSE_TYPE:

    case OGS_PFCP_SESSION_REPORT_REQUEST_TYPE:

    case OGS_PFCP_SESSION_REPORT_RESPONSE_TYPE:

        /* Node ID must not be present for these messages */

        requirement = OGS_PFCP_NODE_ID_NONE;

        break;

    default:

        /* Unknown message type */

        ogs_error("Unknown message type %d", message->h.type);

        return OGS_PFCP_ERROR_UNKNOWN_MESSAGE;

    }

    /* Check requirement vs. tlv_node_id existence */

    switch (requirement) {

    case OGS_PFCP_NODE_ID_MANDATORY:

        /* Must have tlv_node_id. presence must be 1. */

        ogs_assert(tlv_node_id);

        if (!tlv_node_id->presence) {

            status = OGS_PFCP_ERROR_NODE_ID_NOT_PRESENT;

            goto done;

        }

        break;

    case OGS_PFCP_NODE_ID_OPTIONAL:

        /*

         * Must have tlv_node_id. presence=1 => real Node ID

         * presence=0 => no Node ID

         */

        ogs_assert(tlv_node_id);

        if (!tlv_node_id->presence) {

            status = OGS_PFCP_STATUS_NODE_ID_OPTIONAL_ABSENT;

            goto done;

        }

        break;

    case OGS_PFCP_NODE_ID_NONE:

        /* Must be NULL => no Node ID field */

        ogs_assert(tlv_node_id == NULL);

        status = OGS_PFCP_STATUS_NODE_ID_NONE;

        goto done;

    default:

        status = OGS_PFCP_ERROR_UNKNOWN_MESSAGE;

        goto done;

    }

  memcpy(node_id, tlv_node_id->data, ogs_min(tlv_node_id->len, sizeof(ogs_pfcp_node_id_t)));

    node_id->fqdn[OGS_MAX_FQDN_LEN - 1] = '\0';

    if (node_id->type != OGS_PFCP_NODE_ID_IPV4 &&

        node_id->type != OGS_PFCP_NODE_ID_IPV6 &&

        node_id->type != OGS_PFCP_NODE_ID_FQDN) {

        ogs_error("Semantic incorrect message[%d] type[%d]",

                message->h.type, node_id->type);

        return OGS_PFCP_ERROR_SEMANTIC_INCORRECT_MESSAGE;

    }

     /* Node ID is valid */

    status = OGS_PFCP_STATUS_SUCCESS;

done:

    return status;

}

ogs_sockaddr_t *ogs_pfcp_node_id_to_addrinfo(const ogs_pfcp_node_id_t *node_id)

{

    ogs_sockaddr_t *p;

    int ret;

    uint16_t port = ogs_pfcp_self()->pfcp_port;

    char fqdn[OGS_MAX_FQDN_LEN+1];

    ogs_assert(node_id);

    switch (node_id->type) {

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

     * 1) IPv4

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

    case OGS_PFCP_NODE_ID_IPV4:

        p = (ogs_sockaddr_t *)ogs_calloc(1, sizeof(*p));

        if (!p) {

            ogs_error("ogs_calloc() failed");

            return NULL;

        }

        p->sa.sa_family = AF_INET;

        p->sin.sin_port = htobe16(port);

        p->sin.sin_addr.s_addr = node_id->addr;

        p->next = NULL;

        return p;

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

     * 2) IPv6

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

    case OGS_PFCP_NODE_ID_IPV6:

        p = (ogs_sockaddr_t *)ogs_calloc(1, sizeof(*p));

        if (!p) {

            ogs_error("ogs_calloc() failed");

            return NULL;

        }

        p->sa.sa_family = AF_INET6;

        p->sin6.sin6_port = htobe16(port);

        /* Copy 16 bytes of IPv6 address */

        memcpy(&p->sin6.sin6_addr, node_id->addr6, 16);

        p->next = NULL;

        return p;

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

     * 3) FQDN

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

    case OGS_PFCP_NODE_ID_FQDN:

        /* If the FQDN is not empty, we attempt DNS resolution.

         *  ogs_addaddrinfo() is a placeholder for your actual

         *  DNS -> ogs_sockaddr_t function (often wraps getaddrinfo).

         */

        /* Port=0 or set as needed, family=AF_UNSPEC, flags=0. */

        if (ogs_fqdn_parse(fqdn, node_id->fqdn, strlen(node_id->fqdn)) <= 0) {

            ogs_error("ogs_fqdn_parse() error [%s]", node_id->fqdn);

            return NULL;

        }

        ret = ogs_getaddrinfo(&p, AF_UNSPEC, fqdn, port, 0);

        if (ret != 0) {

            /* DNS resolution failed => *out remains NULL */

            ogs_error("ogs_addaddrinfo() failed");

            return NULL;

        }

        /* If FQDN is empty, just return with no addresses. */

        return p;

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

     * 4) Unsupported type or default

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

    default:

        /* Optionally handle an error or just return success

         * with no addresses.

         */

        ogs_error("Unknown type [%d]", node_id->type);

        return NULL;

    }

}

/* Utility function to convert node_id to string for logging */

const char *ogs_pfcp_node_id_to_string_static(

        const ogs_pfcp_node_id_t *node_id)

{

    static char buffer[OGS_MAX_FQDN_LEN+1] = { 0, };

    if (node_id) {

        switch (node_id->type) {

        case OGS_PFCP_NODE_ID_IPV4:

            inet_ntop(AF_INET, &node_id->addr, buffer, sizeof(buffer));

            break;

        case OGS_PFCP_NODE_ID_IPV6:

            inet_ntop(AF_INET6, node_id->addr6, buffer, sizeof(buffer));

            break;

        case OGS_PFCP_NODE_ID_FQDN:

            if (ogs_fqdn_parse(buffer,

                               node_id->fqdn,

                               strlen(node_id->fqdn)) <= 0)

                snprintf(buffer, sizeof(buffer), "%s", node_id->fqdn);

            break;

        default:

            snprintf(buffer, sizeof(buffer), "Unknown");

            break;

        }

    }

    return buffer;

}