/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2012 The FreeBSD Foundation
 *
 * This software was developed by Edward Tomasz Napierala under sponsorship
 * from the FreeBSD Foundation.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 */

#include <sys/time.h>
#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <cam/ctl/ctl.h>
#include <cam/ctl/ctl_io.h>
#include <cam/ctl/ctl_ioctl.h>

#include "ctld.hh"
#include "iscsi.hh"
#include "iscsi_proto.h"

#define MAX_DATA_SEGMENT_LENGTH         (128 * 1024)

static void login_send_error(struct pdu *request,
    char error_class, char detail);

static void
kernel_limits(const char *offload, int s, int *max_recv_dsl, int *max_send_dsl,
    int *max_burst_length, int *first_burst_length)
{
        struct ctl_iscsi req;
        struct ctl_iscsi_limits_params *cilp;

        bzero(&req, sizeof(req));

        req.type = CTL_ISCSI_LIMITS;
        cilp = (struct ctl_iscsi_limits_params *)&(req.data.limits);
        strlcpy(cilp->offload, offload, sizeof(cilp->offload));
        cilp->socket = s;

        if (ioctl(ctl_fd, CTL_ISCSI, &req) == -1) {
                log_err(1, "error issuing CTL_ISCSI ioctl; "
                    "dropping connection");
        }

        if (req.status != CTL_ISCSI_OK) {
                log_errx(1, "error returned from CTL iSCSI limits request: "
                    "%s; dropping connection", req.error_str);
        }

        if (cilp->max_recv_data_segment_length != 0) {
                *max_recv_dsl = cilp->max_recv_data_segment_length;
                *max_send_dsl = cilp->max_recv_data_segment_length;
        }
        if (cilp->max_send_data_segment_length != 0)
                *max_send_dsl = cilp->max_send_data_segment_length;
        if (cilp->max_burst_length != 0)
                *max_burst_length = cilp->max_burst_length;
        if (cilp->first_burst_length != 0)
                *first_burst_length = cilp->first_burst_length;
        if (*max_burst_length < *first_burst_length)
                *first_burst_length = *max_burst_length;

        if (offload[0] != '\0') {
                log_debugx("Kernel limits for offload \"%s\" are "
                    "MaxRecvDataSegment=%d, max_send_dsl=%d, "
                    "MaxBurstLength=%d, FirstBurstLength=%d",
                    offload, *max_recv_dsl, *max_send_dsl, *max_burst_length,
                    *first_burst_length);
        } else {
                log_debugx("Kernel limits are "
                    "MaxRecvDataSegment=%d, max_send_dsl=%d, "
                    "MaxBurstLength=%d, FirstBurstLength=%d",
                    *max_recv_dsl, *max_send_dsl, *max_burst_length,
                    *first_burst_length);
        }
}

static void
login_set_nsg(struct pdu *response, int nsg)
{
        struct iscsi_bhs_login_response *bhslr;

        assert(nsg == BHSLR_STAGE_SECURITY_NEGOTIATION ||
            nsg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION ||
            nsg == BHSLR_STAGE_FULL_FEATURE_PHASE);

        bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs;

        bhslr->bhslr_flags &= 0xFC;
        bhslr->bhslr_flags |= nsg;
        bhslr->bhslr_flags |= BHSLR_FLAGS_TRANSIT;
}

static int
login_csg(const struct pdu *request)
{
        struct iscsi_bhs_login_request *bhslr;

        bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;

        return ((bhslr->bhslr_flags & 0x0C) >> 2);
}

static void
login_set_csg(struct pdu *response, int csg)
{
        struct iscsi_bhs_login_response *bhslr;

        assert(csg == BHSLR_STAGE_SECURITY_NEGOTIATION ||
            csg == BHSLR_STAGE_OPERATIONAL_NEGOTIATION ||
            csg == BHSLR_STAGE_FULL_FEATURE_PHASE);

        bhslr = (struct iscsi_bhs_login_response *)response->pdu_bhs;

        bhslr->bhslr_flags &= 0xF3;
        bhslr->bhslr_flags |= csg << 2;
}

static struct pdu *
login_receive(struct connection *conn, bool initial)
{
        struct pdu *request;
        struct iscsi_bhs_login_request *bhslr;

        request = pdu_new(conn);
        pdu_receive(request);
        if ((request->pdu_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) !=
            ISCSI_BHS_OPCODE_LOGIN_REQUEST) {
                /*
                 * The first PDU in session is special - if we receive any PDU
                 * different than login request, we have to drop the connection
                 * without sending response ("A target receiving any PDU
                 * except a Login request before the Login Phase is started MUST
                 * immediately terminate the connection on which the PDU
                 * was received.")
                 */
                if (initial == false)
                        login_send_error(request, 0x02, 0x0b);
                log_errx(1, "protocol error: received invalid opcode 0x%x",
                    request->pdu_bhs->bhs_opcode);
        }
        bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
        /*
         * XXX: Implement the C flag some day.
         */
        if ((bhslr->bhslr_flags & BHSLR_FLAGS_CONTINUE) != 0) {
                login_send_error(request, 0x03, 0x00);
                log_errx(1, "received Login PDU with unsupported \"C\" flag");
        }
        if (bhslr->bhslr_version_max != 0x00) {
                login_send_error(request, 0x02, 0x05);
                log_errx(1, "received Login PDU with unsupported "
                    "Version-max 0x%x", bhslr->bhslr_version_max);
        }
        if (bhslr->bhslr_version_min != 0x00) {
                login_send_error(request, 0x02, 0x05);
                log_errx(1, "received Login PDU with unsupported "
                    "Version-min 0x%x", bhslr->bhslr_version_min);
        }
        if (initial == false &&
            ISCSI_SNLT(ntohl(bhslr->bhslr_cmdsn), conn->conn_cmdsn)) {
                login_send_error(request, 0x02, 0x00);
                log_errx(1, "received Login PDU with decreasing CmdSN: "
                    "was %u, is %u", conn->conn_cmdsn,
                    ntohl(bhslr->bhslr_cmdsn));
        }
        if (initial == false &&
            ntohl(bhslr->bhslr_expstatsn) != conn->conn_statsn) {
                login_send_error(request, 0x02, 0x00);
                log_errx(1, "received Login PDU with wrong ExpStatSN: "
                    "is %u, should be %u", ntohl(bhslr->bhslr_expstatsn),
                    conn->conn_statsn);
        }
        conn->conn_cmdsn = ntohl(bhslr->bhslr_cmdsn);

        return (request);
}

static struct pdu *
login_new_response(struct pdu *request)
{
        struct pdu *response;
        struct connection *conn;
        struct iscsi_bhs_login_request *bhslr;
        struct iscsi_bhs_login_response *bhslr2;

        bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
        conn = request->pdu_connection;

        response = pdu_new_response(request);
        bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
        bhslr2->bhslr_opcode = ISCSI_BHS_OPCODE_LOGIN_RESPONSE;
        login_set_csg(response, BHSLR_STAGE_SECURITY_NEGOTIATION);
        memcpy(bhslr2->bhslr_isid,
            bhslr->bhslr_isid, sizeof(bhslr2->bhslr_isid));
        bhslr2->bhslr_initiator_task_tag = bhslr->bhslr_initiator_task_tag;
        bhslr2->bhslr_statsn = htonl(conn->conn_statsn++);
        bhslr2->bhslr_expcmdsn = htonl(conn->conn_cmdsn);
        bhslr2->bhslr_maxcmdsn = htonl(conn->conn_cmdsn);

        return (response);
}

static void
login_send_error(struct pdu *request, char error_class, char detail)
{
        struct pdu *response;
        struct iscsi_bhs_login_response *bhslr2;

        log_debugx("sending Login Response PDU with failure class 0x%x/0x%x; "
            "see next line for reason", error_class, detail);
        response = login_new_response(request);
        bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
        bhslr2->bhslr_status_class = error_class;
        bhslr2->bhslr_status_detail = detail;

        pdu_send(response);
        pdu_delete(response);
}

static int
login_list_contains(const char *list, const char *what)
{
        char *tofree, *str, *token;

        tofree = str = checked_strdup(list);

        while ((token = strsep(&str, ",")) != NULL) {
                if (strcmp(token, what) == 0) {
                        free(tofree);
                        return (1);
                }
        }
        free(tofree);
        return (0);
}

static int
login_list_prefers(const char *list,
    const char *choice1, const char *choice2)
{
        char *tofree, *str, *token;

        tofree = str = checked_strdup(list);

        while ((token = strsep(&str, ",")) != NULL) {
                if (strcmp(token, choice1) == 0) {
                        free(tofree);
                        return (1);
                }
                if (strcmp(token, choice2) == 0) {
                        free(tofree);
                        return (2);
                }
        }
        free(tofree);
        return (-1);
}

static struct pdu *
login_receive_chap_a(struct connection *conn)
{
        struct pdu *request;
        struct keys *request_keys;
        const char *chap_a;

        request = login_receive(conn, false);
        request_keys = keys_new();
        keys_load_pdu(request_keys, request);

        chap_a = keys_find(request_keys, "CHAP_A");
        if (chap_a == NULL) {
                login_send_error(request, 0x02, 0x07);
                log_errx(1, "received CHAP Login PDU without CHAP_A");
        }
        if (login_list_contains(chap_a, "5") == 0) {
                login_send_error(request, 0x02, 0x01);
                log_errx(1, "received CHAP Login PDU with unsupported CHAP_A "
                    "\"%s\"", chap_a);
        }
        keys_delete(request_keys);

        return (request);
}

static void
login_send_chap_c(struct pdu *request, struct chap *chap)
{
        struct pdu *response;
        struct keys *response_keys;
        char *chap_c, *chap_i;

        chap_c = chap_get_challenge(chap);
        chap_i = chap_get_id(chap);

        response = login_new_response(request);
        response_keys = keys_new();
        keys_add(response_keys, "CHAP_A", "5");
        keys_add(response_keys, "CHAP_I", chap_i);
        keys_add(response_keys, "CHAP_C", chap_c);
        free(chap_i);
        free(chap_c);
        keys_save_pdu(response_keys, response);
        pdu_send(response);
        pdu_delete(response);
        keys_delete(response_keys);
}

static struct pdu *
login_receive_chap_r(struct connection *conn, struct auth_group *ag,
    struct chap *chap, const struct auth **authp, std::string &user)
{
        struct pdu *request;
        struct keys *request_keys;
        const char *chap_n, *chap_r;
        const struct auth *auth;
        int error;

        request = login_receive(conn, false);
        request_keys = keys_new();
        keys_load_pdu(request_keys, request);

        chap_n = keys_find(request_keys, "CHAP_N");
        if (chap_n == NULL) {
                login_send_error(request, 0x02, 0x07);
                log_errx(1, "received CHAP Login PDU without CHAP_N");
        }
        chap_r = keys_find(request_keys, "CHAP_R");
        if (chap_r == NULL) {
                login_send_error(request, 0x02, 0x07);
                log_errx(1, "received CHAP Login PDU without CHAP_R");
        }
        error = chap_receive(chap, chap_r);
        if (error != 0) {
                login_send_error(request, 0x02, 0x07);
                log_errx(1, "received CHAP Login PDU with malformed CHAP_R");
        }

        /*
         * Verify the response.
         */
        assert(ag->type() == auth_type::CHAP ||
            ag->type() == auth_type::CHAP_MUTUAL);
        auth = ag->find_auth(chap_n);
        if (auth == NULL) {
                login_send_error(request, 0x02, 0x01);
                log_errx(1, "received CHAP Login with invalid user \"%s\"",
                    chap_n);
        }

        error = chap_authenticate(chap, auth->secret());
        if (error != 0) {
                login_send_error(request, 0x02, 0x01);
                log_errx(1, "CHAP authentication failed for user \"%s\"",
                    chap_n);
        }
        user = chap_n;

        keys_delete(request_keys);

        *authp = auth;
        return (request);
}

static void
login_send_chap_success(struct pdu *request,
    const struct auth *auth, const std::string &user)
{
        struct pdu *response;
        struct keys *request_keys, *response_keys;
        struct rchap *rchap;
        const char *chap_i, *chap_c;
        char *chap_r;
        int error;

        response = login_new_response(request);
        login_set_nsg(response, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);

        /*
         * Actually, one more thing: mutual authentication.
         */
        request_keys = keys_new();
        keys_load_pdu(request_keys, request);
        chap_i = keys_find(request_keys, "CHAP_I");
        chap_c = keys_find(request_keys, "CHAP_C");
        if (chap_i != NULL || chap_c != NULL) {
                if (chap_i == NULL) {
                        login_send_error(request, 0x02, 0x07);
                        log_errx(1, "initiator requested target "
                            "authentication, but didn't send CHAP_I");
                }
                if (chap_c == NULL) {
                        login_send_error(request, 0x02, 0x07);
                        log_errx(1, "initiator requested target "
                            "authentication, but didn't send CHAP_C");
                }
                if (!auth->mutual()) {
                        login_send_error(request, 0x02, 0x01);
                        log_errx(1, "initiator requests target authentication "
                            "for user \"%s\", but mutual user/secret "
                            "is not set", user.c_str());
                }

                log_debugx("performing mutual authentication as user \"%s\"",
                    auth->mutual_user());

                rchap = rchap_new(auth->mutual_secret());
                error = rchap_receive(rchap, chap_i, chap_c);
                if (error != 0) {
                        login_send_error(request, 0x02, 0x07);
                        log_errx(1, "received CHAP Login PDU with malformed "
                            "CHAP_I or CHAP_C");
                }
                chap_r = rchap_get_response(rchap);
                rchap_delete(rchap);
                response_keys = keys_new();
                keys_add(response_keys, "CHAP_N", auth->mutual_user());
                keys_add(response_keys, "CHAP_R", chap_r);
                free(chap_r);
                keys_save_pdu(response_keys, response);
                keys_delete(response_keys);
        } else {
                log_debugx("initiator did not request target authentication");
        }

        keys_delete(request_keys);
        pdu_send(response);
        pdu_delete(response);
}

void
iscsi_connection::login_chap(struct auth_group *ag)
{
        std::string user;
        const struct auth *auth;
        struct chap *chap;
        struct pdu *request;

        /*
         * Receive CHAP_A PDU.
         */
        log_debugx("beginning CHAP authentication; waiting for CHAP_A");
        request = login_receive_chap_a(&conn);

        /*
         * Generate the challenge.
         */
        chap = chap_new();

        /*
         * Send the challenge.
         */
        log_debugx("sending CHAP_C, binary challenge size is %zd bytes",
            sizeof(chap->chap_challenge));
        login_send_chap_c(request, chap);
        pdu_delete(request);

        /*
         * Receive CHAP_N/CHAP_R PDU and authenticate.
         */
        log_debugx("waiting for CHAP_N/CHAP_R");
        request = login_receive_chap_r(&conn, ag, chap, &auth, user);

        /*
         * Yay, authentication succeeded!
         */
        log_debugx("authentication succeeded for user \"%s\"; "
            "transitioning to operational parameter negotiation", user.c_str());
        login_send_chap_success(request, auth, user);
        pdu_delete(request);

        /*
         * Leave username and CHAP information for discovery().
         */
        conn_user = user;
        conn_chap = chap;
}

void
iscsi_connection::login_negotiate_key(struct pdu *request, const char *name,
    const char *value, bool skipped_security, struct keys *response_keys)
{
        int which;
        size_t tmp;

        assert(request->pdu_connection == &conn);

        if (strcmp(name, "InitiatorName") == 0) {
                if (!skipped_security)
                        log_errx(1, "initiator resent InitiatorName");
        } else if (strcmp(name, "SessionType") == 0) {
                if (!skipped_security)
                        log_errx(1, "initiator resent SessionType");
        } else if (strcmp(name, "TargetName") == 0) {
                if (!skipped_security)
                        log_errx(1, "initiator resent TargetName");
        } else if (strcmp(name, "InitiatorAlias") == 0) {
                conn_initiator_alias = value;
        } else if (strcmp(value, "Irrelevant") == 0) {
                /* Ignore. */
        } else if (strcmp(name, "HeaderDigest") == 0) {
                /*
                 * We don't handle digests for discovery sessions.
                 */
                if (conn_session_type == CONN_SESSION_TYPE_DISCOVERY) {
                        log_debugx("discovery session; digests disabled");
                        keys_add(response_keys, name, "None");
                        return;
                }

                which = login_list_prefers(value, "CRC32C", "None");
                switch (which) {
                case 1:
                        log_debugx("initiator prefers CRC32C "
                            "for header digest; we'll use it");
                        conn.conn_header_digest = CONN_DIGEST_CRC32C;
                        keys_add(response_keys, name, "CRC32C");
                        break;
                case 2:
                        log_debugx("initiator prefers not to do "
                            "header digest; we'll comply");
                        keys_add(response_keys, name, "None");
                        break;
                default:
                        log_warnx("initiator sent unrecognized "
                            "HeaderDigest value \"%s\"; will use None", value);
                        keys_add(response_keys, name, "None");
                        break;
                }
        } else if (strcmp(name, "DataDigest") == 0) {
                if (conn_session_type == CONN_SESSION_TYPE_DISCOVERY) {
                        log_debugx("discovery session; digests disabled");
                        keys_add(response_keys, name, "None");
                        return;
                }

                which = login_list_prefers(value, "CRC32C", "None");
                switch (which) {
                case 1:
                        log_debugx("initiator prefers CRC32C "
                            "for data digest; we'll use it");
                        conn.conn_data_digest = CONN_DIGEST_CRC32C;
                        keys_add(response_keys, name, "CRC32C");
                        break;
                case 2:
                        log_debugx("initiator prefers not to do "
                            "data digest; we'll comply");
                        keys_add(response_keys, name, "None");
                        break;
                default:
                        log_warnx("initiator sent unrecognized "
                            "DataDigest value \"%s\"; will use None", value);
                        keys_add(response_keys, name, "None");
                        break;
                }
        } else if (strcmp(name, "MaxConnections") == 0) {
                keys_add(response_keys, name, "1");
        } else if (strcmp(name, "InitialR2T") == 0) {
                keys_add(response_keys, name, "Yes");
        } else if (strcmp(name, "ImmediateData") == 0) {
                if (conn_session_type == CONN_SESSION_TYPE_DISCOVERY) {
                        log_debugx("discovery session; ImmediateData irrelevant");
                        keys_add(response_keys, name, "Irrelevant");
                } else {
                        if (strcmp(value, "Yes") == 0) {
                                conn.conn_immediate_data = true;
                                keys_add(response_keys, name, "Yes");
                        } else {
                                conn.conn_immediate_data = false;
                                keys_add(response_keys, name, "No");
                        }
                }
        } else if (strcmp(name, "MaxRecvDataSegmentLength") == 0) {
                tmp = strtoul(value, NULL, 10);
                if (tmp <= 0) {
                        login_send_error(request, 0x02, 0x00);
                        log_errx(1, "received invalid "
                            "MaxRecvDataSegmentLength");
                }

                /*
                 * MaxRecvDataSegmentLength is a direction-specific parameter.
                 * We'll limit our _send_ to what the initiator can handle but
                 * our MaxRecvDataSegmentLength is not influenced by the
                 * initiator in any way.
                 */
                if ((int)tmp > conn_max_send_data_segment_limit) {
                        log_debugx("capping MaxRecvDataSegmentLength "
                            "from %zd to %d", tmp,
                            conn_max_send_data_segment_limit);
                        tmp = conn_max_send_data_segment_limit;
                }
                conn.conn_max_send_data_segment_length = tmp;
        } else if (strcmp(name, "MaxBurstLength") == 0) {
                tmp = strtoul(value, NULL, 10);
                if (tmp <= 0) {
                        login_send_error(request, 0x02, 0x00);
                        log_errx(1, "received invalid MaxBurstLength");
                }
                if ((int)tmp > conn_max_burst_limit) {
                        log_debugx("capping MaxBurstLength from %zd to %d",
                            tmp, conn_max_burst_limit);
                        tmp = conn_max_burst_limit;
                }
                conn.conn_max_burst_length = tmp;
                keys_add_int(response_keys, name, tmp);
        } else if (strcmp(name, "FirstBurstLength") == 0) {
                tmp = strtoul(value, NULL, 10);
                if (tmp <= 0) {
                        login_send_error(request, 0x02, 0x00);
                        log_errx(1, "received invalid FirstBurstLength");
                }
                if ((int)tmp > conn_first_burst_limit) {
                        log_debugx("capping FirstBurstLength from %zd to %d",
                            tmp, conn_first_burst_limit);
                        tmp = conn_first_burst_limit;
                }
                conn.conn_first_burst_length = tmp;
                keys_add_int(response_keys, name, tmp);
        } else if (strcmp(name, "DefaultTime2Wait") == 0) {
                keys_add(response_keys, name, value);
        } else if (strcmp(name, "DefaultTime2Retain") == 0) {
                keys_add(response_keys, name, "0");
        } else if (strcmp(name, "MaxOutstandingR2T") == 0) {
                keys_add(response_keys, name, "1");
        } else if (strcmp(name, "DataPDUInOrder") == 0) {
                keys_add(response_keys, name, "Yes");
        } else if (strcmp(name, "DataSequenceInOrder") == 0) {
                keys_add(response_keys, name, "Yes");
        } else if (strcmp(name, "ErrorRecoveryLevel") == 0) {
                keys_add(response_keys, name, "0");
        } else if (strcmp(name, "OFMarker") == 0) {
                keys_add(response_keys, name, "No");
        } else if (strcmp(name, "IFMarker") == 0) {
                keys_add(response_keys, name, "No");
        } else if (strcmp(name, "iSCSIProtocolLevel") == 0) {
                tmp = strtoul(value, NULL, 10);
                if (tmp > 2)
                        tmp = 2;
                keys_add_int(response_keys, name, tmp);
        } else {
                log_debugx("unknown key \"%s\"; responding "
                    "with NotUnderstood", name);
                keys_add(response_keys, name, "NotUnderstood");
        }
}

static void
login_redirect(struct pdu *request, const char *target_address)
{
        struct pdu *response;
        struct iscsi_bhs_login_response *bhslr2;
        struct keys *response_keys;

        response = login_new_response(request);
        login_set_csg(response, login_csg(request));
        bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
        bhslr2->bhslr_status_class = 0x01;
        bhslr2->bhslr_status_detail = 0x01;

        response_keys = keys_new();
        keys_add(response_keys, "TargetAddress", target_address);

        keys_save_pdu(response_keys, response);
        pdu_send(response);
        pdu_delete(response);
        keys_delete(response_keys);
}

bool
iscsi_connection::login_portal_redirect(struct pdu *request)
{
        const struct portal_group *pg;

        pg = conn_portal->portal_group();
        if (!pg->is_redirecting())
                return (false);

        log_debugx("portal-group \"%s\" configured to redirect to %s",
            pg->name(), pg->redirection());
        login_redirect(request, pg->redirection());

        return (true);
}

bool
iscsi_connection::login_target_redirect(struct pdu *request)
{
        const char *target_address;

        assert(!conn_portal->portal_group()->is_redirecting());

        if (conn_target == NULL)
                return (false);

        if (!conn_target->has_redirection())
                return (false);

        target_address = conn_target->redirection();
        log_debugx("target \"%s\" configured to redirect to %s",
          conn_target->name(), target_address);
        login_redirect(request, target_address);

        return (true);
}

void
iscsi_connection::login_negotiate(struct pdu *request)
{
        struct portal_group *pg = conn_portal->portal_group();
        struct pdu *response;
        struct iscsi_bhs_login_response *bhslr2;
        struct keys *request_keys, *response_keys;
        int i;
        bool redirected, skipped_security;

        if (conn_session_type == CONN_SESSION_TYPE_NORMAL) {
                /*
                 * Query the kernel for various size limits.  In case of
                 * offload, it depends on hardware capabilities.
                 */
                assert(conn_target != NULL);
                conn_max_recv_data_segment_limit = (1 << 24) - 1;
                conn_max_send_data_segment_limit = (1 << 24) - 1;
                conn_max_burst_limit = (1 << 24) - 1;
                conn_first_burst_limit = (1 << 24) - 1;
                kernel_limits(pg->offload(),
                    conn_fd,
                    &conn_max_recv_data_segment_limit,
                    &conn_max_send_data_segment_limit,
                    &conn_max_burst_limit,
                    &conn_first_burst_limit);

                /* We expect legal, usable values at this point. */
                assert(conn_max_recv_data_segment_limit >= 512);
                assert(conn_max_recv_data_segment_limit < (1 << 24));
                assert(conn_max_send_data_segment_limit >= 512);
                assert(conn_max_send_data_segment_limit < (1 << 24));
                assert(conn_max_burst_limit >= 512);
                assert(conn_max_burst_limit < (1 << 24));
                assert(conn_first_burst_limit >= 512);
                assert(conn_first_burst_limit < (1 << 24));
                assert(conn_first_burst_limit <= conn_max_burst_limit);

                /*
                 * Limit default send length in case it won't be negotiated.
                 * We can't do it for other limits, since they may affect both
                 * sender and receiver operation, and we must obey defaults.
                 */
                if (conn_max_send_data_segment_limit <
                    conn.conn_max_send_data_segment_length) {
                        conn.conn_max_send_data_segment_length =
                            conn_max_send_data_segment_limit;
                }
        } else {
                conn_max_recv_data_segment_limit = MAX_DATA_SEGMENT_LENGTH;
                conn_max_send_data_segment_limit = MAX_DATA_SEGMENT_LENGTH;
        }

        if (request == NULL) {
                log_debugx("beginning operational parameter negotiation; "
                    "waiting for Login PDU");
                request = login_receive(&conn, false);
                skipped_security = false;
        } else
                skipped_security = true;

        /*
         * RFC 3720, 10.13.5.  Status-Class and Status-Detail, says
         * the redirection SHOULD be accepted by the initiator before
         * authentication, but MUST be accepted afterwards; that's
         * why we're doing it here and not earlier.
         */
        redirected = login_target_redirect(request);
        if (redirected) {
                log_debugx("initiator redirected; exiting");
                exit(0);
        }

        request_keys = keys_new();
        keys_load_pdu(request_keys, request);

        response = login_new_response(request);
        bhslr2 = (struct iscsi_bhs_login_response *)response->pdu_bhs;
        bhslr2->bhslr_tsih = htons(0xbadd);
        login_set_csg(response, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
        login_set_nsg(response, BHSLR_STAGE_FULL_FEATURE_PHASE);
        response_keys = keys_new();

        if (skipped_security &&
            conn_session_type == CONN_SESSION_TYPE_NORMAL) {
                if (conn_target->has_alias())
                        keys_add(response_keys,
                            "TargetAlias", conn_target->alias());
                keys_add_int(response_keys, "TargetPortalGroupTag",
                    pg->tag());
        }

        for (i = 0; i < KEYS_MAX; i++) {
                if (request_keys->keys_names[i] == NULL)
                        break;

                login_negotiate_key(request, request_keys->keys_names[i],
                    request_keys->keys_values[i], skipped_security,
                    response_keys);
        }

        /*
         * We'd started with usable values at our end.  But a bad initiator
         * could have presented a large FirstBurstLength and then a smaller
         * MaxBurstLength (in that order) and because we process the key/value
         * pairs in the order they are in the request we might have ended up
         * with illegal values here.
         */
        if (conn_session_type == CONN_SESSION_TYPE_NORMAL &&
            conn.conn_first_burst_length > conn.conn_max_burst_length) {
                log_errx(1, "initiator sent FirstBurstLength > MaxBurstLength");
        }

        conn.conn_max_recv_data_segment_length =
            conn_max_recv_data_segment_limit;
        keys_add_int(response_keys, "MaxRecvDataSegmentLength",
                    conn.conn_max_recv_data_segment_length);

        log_debugx("operational parameter negotiation done; "
            "transitioning to Full Feature Phase");

        keys_save_pdu(response_keys, response);
        pdu_send(response);
        pdu_delete(response);
        keys_delete(response_keys);
        pdu_delete(request);
        keys_delete(request_keys);
}

void
iscsi_connection::login_wait_transition()
{
        struct pdu *request, *response;
        struct iscsi_bhs_login_request *bhslr;

        log_debugx("waiting for state transition request");
        request = login_receive(&conn, false);
        bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
        if ((bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) == 0) {
                login_send_error(request, 0x02, 0x00);
                log_errx(1, "got no \"T\" flag after answering AuthMethod");
        }

        log_debugx("got state transition request");
        response = login_new_response(request);
        pdu_delete(request);
        login_set_nsg(response, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
        pdu_send(response);
        pdu_delete(response);

        login_negotiate(nullptr);
}

void
iscsi_connection::login()
{
        struct pdu *request, *response;
        struct iscsi_bhs_login_request *bhslr;
        struct keys *request_keys, *response_keys;
        struct auth_group *ag;
        struct portal_group *pg;
        const char *initiator_name, *initiator_alias, *session_type,
            *target_name, *auth_method;
        bool redirected, fail, trans;

        /*
         * Handle the initial Login Request - figure out required authentication
         * method and either transition to the next phase, if no authentication
         * is required, or call appropriate authentication code.
         */
        log_debugx("beginning Login Phase; waiting for Login PDU");
        request = login_receive(&conn, true);
        bhslr = (struct iscsi_bhs_login_request *)request->pdu_bhs;
        if (bhslr->bhslr_tsih != 0) {
                login_send_error(request, 0x02, 0x0a);
                log_errx(1, "received Login PDU with non-zero TSIH");
        }

        pg = conn_portal->portal_group();

        memcpy(conn_initiator_isid, bhslr->bhslr_isid,
            sizeof(conn_initiator_isid));

        /*
         * XXX: Implement the C flag some day.
         */
        request_keys = keys_new();
        keys_load_pdu(request_keys, request);

        assert(conn_initiator_name.empty());
        initiator_name = keys_find(request_keys, "InitiatorName");
        if (initiator_name == NULL) {
                login_send_error(request, 0x02, 0x07);
                log_errx(1, "received Login PDU without InitiatorName");
        }
        if (valid_iscsi_name(initiator_name, log_warnx) == false) {
                login_send_error(request, 0x02, 0x00);
                log_errx(1, "received Login PDU with invalid InitiatorName");
        }
        conn_initiator_name = initiator_name;
        log_set_peer_name(conn_initiator_name.c_str());
        setproctitle("%s (%s)", conn_initiator_addr.c_str(),
            conn_initiator_name.c_str());

        redirected = login_portal_redirect(request);
        if (redirected) {
                log_debugx("initiator redirected; exiting");
                exit(0);
        }

        initiator_alias = keys_find(request_keys, "InitiatorAlias");
        if (initiator_alias != NULL)
                conn_initiator_alias = initiator_alias;

        assert(conn_session_type == CONN_SESSION_TYPE_NONE);
        session_type = keys_find(request_keys, "SessionType");
        if (session_type != NULL) {
                if (strcmp(session_type, "Normal") == 0) {
                        conn_session_type = CONN_SESSION_TYPE_NORMAL;
                } else if (strcmp(session_type, "Discovery") == 0) {
                        conn_session_type = CONN_SESSION_TYPE_DISCOVERY;
                } else {
                        login_send_error(request, 0x02, 0x00);
                        log_errx(1, "received Login PDU with invalid "
                            "SessionType \"%s\"", session_type);
                }
        } else
                conn_session_type = CONN_SESSION_TYPE_NORMAL;

        assert(conn_target == NULL);
        if (conn_session_type == CONN_SESSION_TYPE_NORMAL) {
                target_name = keys_find(request_keys, "TargetName");
                if (target_name == NULL) {
                        login_send_error(request, 0x02, 0x07);
                        log_errx(1, "received Login PDU without TargetName");
                }

                conn_port = pg->find_port(target_name);
                if (conn_port == NULL) {
                        login_send_error(request, 0x02, 0x03);
                        log_errx(1, "requested target \"%s\" not found",
                            target_name);
                }
                conn_target = conn_port->target();
        }

        /*
         * At this point we know what kind of authentication we need.
         */
        if (conn_session_type == CONN_SESSION_TYPE_NORMAL) {
                ag = conn_port->auth_group();
                if (ag == nullptr)
                        ag = conn_target->auth_group();
                if (conn_port->auth_group() == nullptr &&
                    conn_target->private_auth()) {
                        log_debugx("initiator requests to connect "
                            "to target \"%s\"", conn_target->name());
                } else {
                        log_debugx("initiator requests to connect "
                            "to target \"%s\"; %s",
                            conn_target->name(), ag->label());
                }
        } else {
                assert(conn_session_type == CONN_SESSION_TYPE_DISCOVERY);
                ag = pg->discovery_auth_group();
                log_debugx("initiator requests discovery session; %s",
                    ag->label());
        }

        if (ag->type() == auth_type::DENY) {
                login_send_error(request, 0x02, 0x01);
                log_errx(1, "auth-type is \"deny\"");
        }

        if (ag->type() == auth_type::UNKNOWN) {
                /*
                 * This can happen with empty auth-group.
                 */
                login_send_error(request, 0x02, 0x01);
                log_errx(1, "auth-type not set, denying access");
        }

        /*
         * Enforce initiator-name and initiator-portal.
         */
        if (!ag->initiator_permitted(initiator_name)) {
                login_send_error(request, 0x02, 0x02);
                log_errx(1, "initiator does not match allowed initiator names");
        }

        if (!ag->initiator_permitted(conn_initiator_sa)) {
                login_send_error(request, 0x02, 0x02);
                log_errx(1, "initiator does not match allowed "
                    "initiator portals");
        }

        /*
         * Let's see if the initiator intends to do any kind of authentication
         * at all.
         */
        if (login_csg(request) == BHSLR_STAGE_OPERATIONAL_NEGOTIATION) {
                if (ag->type() != auth_type::NO_AUTHENTICATION) {
                        login_send_error(request, 0x02, 0x01);
                        log_errx(1, "initiator skipped the authentication, "
                            "but authentication is required");
                }

                keys_delete(request_keys);

                log_debugx("initiator skipped the authentication, "
                    "and we don't need it; proceeding with negotiation");
                login_negotiate(request);
                return;
        }

        fail = false;
        response = login_new_response(request);
        response_keys = keys_new();
        trans = (bhslr->bhslr_flags & BHSLR_FLAGS_TRANSIT) != 0;
        auth_method = keys_find(request_keys, "AuthMethod");
        if (ag->type() == auth_type::NO_AUTHENTICATION) {
                log_debugx("authentication not required");
                if (auth_method == NULL ||
                    login_list_contains(auth_method, "None")) {
                        keys_add(response_keys, "AuthMethod", "None");
                } else {
                        log_warnx("initiator requests "
                            "AuthMethod \"%s\" instead of \"None\"",
                            auth_method);
                        keys_add(response_keys, "AuthMethod", "Reject");
                }
                if (trans)
                        login_set_nsg(response, BHSLR_STAGE_OPERATIONAL_NEGOTIATION);
        } else {
                log_debugx("CHAP authentication required");
                if (auth_method == NULL ||
                    login_list_contains(auth_method, "CHAP")) {
                        keys_add(response_keys, "AuthMethod", "CHAP");
                } else {
                        log_warnx("initiator requests unsupported "
                            "AuthMethod \"%s\" instead of \"CHAP\"",
                            auth_method);
                        keys_add(response_keys, "AuthMethod", "Reject");
                        fail = true;
                }
        }
        if (conn_session_type == CONN_SESSION_TYPE_NORMAL) {
                if (conn_target->has_alias())
                        keys_add(response_keys,
                            "TargetAlias", conn_target->alias());
                keys_add_int(response_keys,
                    "TargetPortalGroupTag", pg->tag());
        }
        keys_save_pdu(response_keys, response);

        pdu_send(response);
        pdu_delete(response);
        keys_delete(response_keys);
        pdu_delete(request);
        keys_delete(request_keys);

        if (fail) {
                log_debugx("sent reject for AuthMethod; exiting");
                exit(1);
        }

        if (ag->type() != auth_type::NO_AUTHENTICATION) {
                login_chap(ag);
                login_negotiate(nullptr);
        } else if (trans) {
                login_negotiate(nullptr);
        } else {
                login_wait_transition();
        }
}