/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <poll.h>
#include <errno.h>

#include "isns_server.h"
#include "isns_log.h"
#include "isns_pdu.h"

#define ISNS_MAX_IOVEC          5
#define MAX_XID                 (2^16)
#define MAX_RCV_RSP_COUNT       10      /* Maximum number of unmatched xid */
#define ISNS_RCV_RETRY_MAX      2
#define IPV4_RSVD_BYTES         10

/* externs */
#ifdef DEBUG
extern void dump_pdu2(isns_pdu_t *);
#endif

/*
 * local functions.
 */

size_t
isns_rcv_pdu(
        int fd,
        isns_pdu_t **pdu,
        size_t *pdu_size,
        int rcv_timeout
)
{
        int poll_cnt;
        struct pollfd fds;
        iovec_t iovec[ISNS_MAX_IOVEC];
        isns_pdu_t *tmp_pdu_hdr;
        ssize_t bytes_received, total_bytes_received = 0;
        struct msghdr msg;
        uint8_t *tmp_pdu_data;

        uint16_t payload_len = 0;

        /* initialize to zero */
        *pdu = NULL;
        *pdu_size = 0;

        fds.fd = fd;
        fds.events = (POLLIN | POLLRDNORM);
        fds.revents = 0;

        /* Receive the header first */
        tmp_pdu_hdr = (isns_pdu_t *)malloc(ISNSP_HEADER_SIZE);
        if (tmp_pdu_hdr == NULL) {
                return (0);
        }
        (void) memset((void *)&tmp_pdu_hdr[0], 0, ISNSP_HEADER_SIZE);
        (void) memset((void *)&iovec[0], 0, sizeof (iovec_t));
        iovec[0].iov_base = (void *)tmp_pdu_hdr;
        iovec[0].iov_len = ISNSP_HEADER_SIZE;

        /* Initialization of the message header. */
        bzero(&msg, sizeof (msg));
        msg.msg_iov = &iovec[0];
        /* msg.msg_flags   = MSG_WAITALL, */
        msg.msg_iovlen  = 1;

        /* Poll and receive the pdu header */
        poll_cnt = 0;
        do {
                int err = poll(&fds, 1, rcv_timeout * 1000);
                if (err <= 0) {
                        poll_cnt ++;
                } else {
                        bytes_received = recvmsg(fd, &msg, MSG_WAITALL);
                        break;
                }
        } while (poll_cnt < ISNS_RCV_RETRY_MAX);

        if (poll_cnt >= ISNS_RCV_RETRY_MAX) {
                free(tmp_pdu_hdr);
                return (0);
        }

        if (bytes_received <= 0) {
                free(tmp_pdu_hdr);
                return (0);
        }

        total_bytes_received += bytes_received;

        payload_len = ntohs(tmp_pdu_hdr->payload_len);
        /* Verify the received payload len is within limit */
        if (payload_len > ISNSP_MAX_PAYLOAD_SIZE) {
                free(tmp_pdu_hdr);
                return (0);
        }

        /* Proceed to receive additional data. */
        tmp_pdu_data = malloc(payload_len);
        if (tmp_pdu_data == NULL) {
                free(tmp_pdu_hdr);
                return (0);
        }
        (void) memset((void *)&iovec[0], 0, sizeof (iovec_t));
        iovec[0].iov_base = (void *)tmp_pdu_data;
        iovec[0].iov_len = payload_len;

        /* Initialization of the message header. */
        bzero(&msg, sizeof (msg));
        msg.msg_iov = &iovec[0];
        /* msg.msg_flags   = MSG_WAITALL, */
        msg.msg_iovlen  = 1;

        /* poll and receive the pdu payload */
        poll_cnt = 0;
        do {
                int err = poll(&fds, 1, rcv_timeout * 1000);
                if (err <= 0) {
                        poll_cnt ++;
                } else {
                        bytes_received = recvmsg(fd, &msg, MSG_WAITALL);
                        break;
                }
        } while (poll_cnt < ISNS_RCV_RETRY_MAX);

        if (poll_cnt >= ISNS_RCV_RETRY_MAX) {
                free(tmp_pdu_data);
                free(tmp_pdu_hdr);
                return (0);
        }

        if (bytes_received <= 0) {
                free(tmp_pdu_data);
                free(tmp_pdu_hdr);
                return (0);
        }

        total_bytes_received += bytes_received;

        *pdu_size = ISNSP_HEADER_SIZE + payload_len;
        (*pdu) = (isns_pdu_t *)malloc(*pdu_size);
        if (*pdu == NULL) {
                *pdu_size = 0;
                free(tmp_pdu_data);
                free(tmp_pdu_hdr);
                return (0);
        }
        (*pdu)->version = ntohs(tmp_pdu_hdr->version);
        (*pdu)->func_id = ntohs(tmp_pdu_hdr->func_id);
        (*pdu)->payload_len = payload_len;
        (*pdu)->flags = ntohs(tmp_pdu_hdr->flags);
        (*pdu)->xid = ntohs(tmp_pdu_hdr->xid);
        (*pdu)->seq = ntohs(tmp_pdu_hdr->seq);
        (void) memcpy(&((*pdu)->payload), tmp_pdu_data, payload_len);

        free(tmp_pdu_data);
        tmp_pdu_data = NULL;
        free(tmp_pdu_hdr);
        tmp_pdu_hdr = NULL;

        return (total_bytes_received);
}

int
isns_send_pdu(
        int fd,
        isns_pdu_t *pdu,
        size_t pl
)
{
        uint8_t *payload;
        uint16_t flags;
        uint16_t seq;
        iovec_t iovec[ISNS_MAX_IOVEC];
        struct msghdr msg = { 0 };

        size_t send_len;
        ssize_t bytes_sent;


        /* Initialization of the message header. */
        msg.msg_iov = &iovec[0];
        /* msg.msg_flags   = MSG_WAITALL, */
        msg.msg_iovlen  = 2;

        /*
         * Initialize the pdu flags.
         */
        flags = ISNS_FLAG_SERVER;
        flags |= ISNS_FLAG_FIRST_PDU;

        /*
         * Initialize the pdu sequence id.
         */
        seq = 0;

        iovec[0].iov_base = (void *)pdu;
        iovec[0].iov_len = (ISNSP_HEADER_SIZE);

        payload = pdu->payload;

#ifdef DEBUG
        pdu->flags = htons(flags);
        pdu->seq = htons(0);
        pdu->payload_len = htons(pl);
        dump_pdu2(pdu);
#endif

        do {
                /* set the payload for sending */
                iovec[1].iov_base = (void *)payload;

                if (pl > ISNSP_MAX_PAYLOAD_SIZE) {
                        send_len = ISNSP_MAX_PAYLOAD_SIZE;
                } else {
                        send_len = pl;
                        /* set the last pdu flag */
                        flags |= ISNS_FLAG_LAST_PDU;
                }
                iovec[1].iov_len = send_len;
                pdu->payload_len = htons(send_len);

                /* set the pdu flags */
                pdu->flags = htons(flags);
                /* set the pdu sequence id */
                pdu->seq = htons(seq);

                /* send the packet */
                bytes_sent = sendmsg(fd, &msg, 0);

                /* get rid of the first pdu flag */
                flags &= ~(ISNS_FLAG_FIRST_PDU);

                /* next part of payload */
                payload += send_len;
                pl -= send_len;

                /* add the length of header for verification */
                send_len += ISNSP_HEADER_SIZE;

                /* increase the sequence id by one */
                seq ++;
        } while (bytes_sent == send_len && pl > 0);

        if (bytes_sent == send_len) {
                return (0);
        } else {
                isnslog(LOG_DEBUG, "isns_send_pdu", "sending pdu failed.");
                return (-1);
        }
}

#define RSP_PDU_FRAG_SZ (ISNSP_MAX_PDU_SIZE / 10)
static int
pdu_reset(
        isns_pdu_t **rsp,
        size_t *sz
)
{
        int ec = 0;

        if (*rsp == NULL) {
                *rsp = (isns_pdu_t *)malloc(RSP_PDU_FRAG_SZ);
                if (*rsp != NULL) {
                        *sz = RSP_PDU_FRAG_SZ;
                } else {
                        ec = ISNS_RSP_INTERNAL_ERROR;
                }
        }

        return (ec);
}

int
pdu_reset_rsp(
        isns_pdu_t **rsp,
        size_t *pl,
        size_t *sz
)
{
        int ec = pdu_reset(rsp, sz);

        if (ec == 0) {
                /* leave space for status code */
                *pl = 4;
        }

        return (ec);
}

int
pdu_reset_scn(
        isns_pdu_t **pdu,
        size_t *pl,
        size_t *sz
)
{
        int ec = pdu_reset(pdu, sz);

        if (ec == 0) {
                *pl = 0;
        }

        return (ec);
}

int
pdu_reset_esi(
        isns_pdu_t **pdu,
        size_t *pl,
        size_t *sz
)
{
        return (pdu_reset_scn(pdu, pl, sz));
}

int
pdu_update_code(
        isns_pdu_t *pdu,
        size_t *pl,
        int code
)
{
        isns_resp_t *resp;

        resp = (isns_resp_t *)pdu->payload;

        /* reset the payload length */
        if (code != ISNS_RSP_SUCCESSFUL || *pl == 0) {
                *pl = 4;
        }

        resp->status = htonl(code);

        return (0);
}

int
pdu_add_tlv(
        isns_pdu_t **pdu,
        size_t *pl,
        size_t *sz,
        uint32_t attr_id,
        uint32_t attr_len,
        void *attr_data,
        int pflag
)
{
        int ec = 0;

        isns_pdu_t *new_pdu;
        size_t new_sz;

        isns_tlv_t *attr_tlv;
        uint8_t *payload_ptr;
        uint32_t normalized_attr_len;
        uint64_t attr_tlv_len;

        /* The attribute length must be 4-byte aligned. Section 5.1.3. */
        normalized_attr_len = (attr_len % 4) == 0 ? (attr_len) :
            (attr_len + (4 - (attr_len % 4)));
        attr_tlv_len = ISNS_TLV_ATTR_ID_LEN
            + ISNS_TLV_ATTR_LEN_LEN
            + normalized_attr_len;
        /* Check if we are going to exceed the maximum PDU length. */
        if ((ISNSP_HEADER_SIZE + *pl + attr_tlv_len) > *sz) {
                new_sz = *sz + RSP_PDU_FRAG_SZ;
                new_pdu = (isns_pdu_t *)realloc(*pdu, new_sz);
                if (new_pdu != NULL) {
                        *sz = new_sz;
                        *pdu = new_pdu;
                } else {
                        ec = ISNS_RSP_INTERNAL_ERROR;
                        return (ec);
                }
        }

        attr_tlv = (isns_tlv_t *)malloc(attr_tlv_len);
        (void) memset((void *)attr_tlv, 0, attr_tlv_len);

        attr_tlv->attr_id = htonl(attr_id);

        switch (attr_id) {
                case ISNS_DELIMITER_ATTR_ID:
                break;

                case ISNS_PORTAL_IP_ADDR_ATTR_ID:
                case ISNS_PG_PORTAL_IP_ADDR_ATTR_ID:
                        /* IPv6 */
                        ASSERT(attr_len == sizeof (in6_addr_t));
                        (void) memcpy(attr_tlv->attr_value, attr_data,
                            sizeof (in6_addr_t));
                break;

                case ISNS_EID_ATTR_ID:
                case ISNS_ISCSI_NAME_ATTR_ID:
                case ISNS_ISCSI_ALIAS_ATTR_ID:
                case ISNS_PG_ISCSI_NAME_ATTR_ID:
                        (void) memcpy(attr_tlv->attr_value, (char *)attr_data,
                            attr_len);
                break;

                default:
                        if (attr_len == 8) {
                                if (pflag == 0) {
                                /*
                                 * In the iSNS protocol, there is only one
                                 * attribute ISNS_TIMESTAMP_ATTR_ID which has
                                 * 8 bytes length integer value and when the
                                 * function "pdu_add_tlv" is called for adding
                                 * the timestamp attribute, the value of
                                 * the attribute is always passed in as its
                                 * address, i.e. the pflag sets to 1.
                                 * So it is an error when we get to this code
                                 * path.
                                 */
                                        ec = ISNS_RSP_INTERNAL_ERROR;
                                        return (ec);
                                } else {
                                        *(uint64_t *)attr_tlv->attr_value =
                                            *(uint64_t *)attr_data;
                                }
                        } else if (attr_len == 4) {
                                if (pflag == 0) {
                                        *(uint32_t *)attr_tlv->attr_value =
                                            htonl((uint32_t)attr_data);
                                } else {
                                        *(uint32_t *)attr_tlv->attr_value =
                                            *(uint32_t *)attr_data;
                                }
                        }
                break;
        }

        attr_tlv->attr_len = htonl(normalized_attr_len);
        /*
         * Convert the network byte ordered payload length to host byte
         * ordered for local address calculation.
         */
        payload_ptr = (*pdu)->payload + *pl;
        (void) memcpy(payload_ptr, attr_tlv, attr_tlv_len);
        *pl += attr_tlv_len;

        /*
         * The payload length might exceed the maximum length of a
         * payload that isnsp allows, we will split the payload and
         * set the size of each payload before they are sent.
         */

        free(attr_tlv);
        attr_tlv = NULL;

        return (ec);
}

isns_tlv_t *
pdu_get_source(
        isns_pdu_t *pdu
)
{
        uint8_t *payload = &pdu->payload[0];
        uint16_t payload_len = pdu->payload_len;
        isns_tlv_t *tlv = NULL;

        /* response code */
        if (pdu->func_id & ISNS_RSP_MASK) {
                if (payload_len < 4) {
                        return (NULL);
                }
                payload += 4;
                payload_len -= 4;
        }

        if (payload_len > 8) {
                tlv = (isns_tlv_t *)payload;
                tlv->attr_id = ntohl(tlv->attr_id);
                tlv->attr_len = ntohl(tlv->attr_len);
        }

        return (tlv);
}

isns_tlv_t *
pdu_get_key(
        isns_pdu_t *pdu,
        size_t *key_len
)
{
        uint8_t *payload = &pdu->payload[0];
        uint16_t payload_len = pdu->payload_len;
        isns_tlv_t *tlv, *key;

        /* reset */
        *key_len = 0;

        /* response code */
        if (pdu->func_id & ISNS_RSP_MASK) {
                if (payload_len <= 4) {
                        return (NULL);
                }
                payload += 4;
                payload_len -= 4;
        }

        /* skip the soure */
        if (payload_len >= 8) {
                tlv = (isns_tlv_t *)payload;
                payload += (8 + tlv->attr_len);
                payload_len -= (8 + tlv->attr_len);
                key = (isns_tlv_t *)payload;
                while (payload_len >= 8) {
                        tlv = (isns_tlv_t *)payload;
                        tlv->attr_id = ntohl(tlv->attr_id);
                        tlv->attr_len = ntohl(tlv->attr_len);
                        if (tlv->attr_id == ISNS_DELIMITER_ATTR_ID) {
                                break;
                        }
                        *key_len += (8 + tlv->attr_len);
                        payload += (8 + tlv->attr_len);
                        payload_len -= (8 + tlv->attr_len);
                }
        }

        if (*key_len >= 8) {
                return (key);
        }

        return (NULL);
}

isns_tlv_t *
pdu_get_operand(
        isns_pdu_t *pdu,
        size_t *op_len
)
{
        uint8_t *payload = &pdu->payload[0];
        uint16_t payload_len = pdu->payload_len;
        isns_tlv_t *tlv, *op = NULL;
        int found_op = 0;

        /* reset */
        *op_len = 0;

        /* response code */
        if (pdu->func_id & ISNS_RSP_MASK) {
                if (payload_len < 4) {
                        return (NULL);
                }
                payload += 4;
                payload_len -= 4;
        }

        /* tlvs */
        while (payload_len >= 8) {
                tlv = (isns_tlv_t *)payload;
                if (found_op != 0) {
                        tlv->attr_id = ntohl(tlv->attr_id);
                        tlv->attr_len = ntohl(tlv->attr_len);
                        payload += (8 + tlv->attr_len);
                        payload_len -= (8 + tlv->attr_len);
                } else {
                        payload += (8 + tlv->attr_len);
                        payload_len -= (8 + tlv->attr_len);
                        if (tlv->attr_id == ISNS_DELIMITER_ATTR_ID) {
                                /* found it */
                                op = (isns_tlv_t *)payload;
                                *op_len = payload_len;
                                found_op = 1;
                        }
                }
        }

        if (*op_len >= 8) {
                return (op);
        }

        return (NULL);
}