// SPDX-License-Identifier: GPL-2.0
/*
 * Discovery service for the NVMe over Fabrics target.
 * Copyright (C) 2016 Intel Corporation. All rights reserved.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include <generated/utsrelease.h>
#include "nvmet.h"

struct nvmet_subsys *nvmet_disc_subsys;

static u64 nvmet_genctr;

static void __nvmet_disc_changed(struct nvmet_port *port,
                                 struct nvmet_ctrl *ctrl)
{
        if (ctrl->port != port)
                return;

        if (nvmet_aen_bit_disabled(ctrl, NVME_AEN_BIT_DISC_CHANGE))
                return;

        nvmet_add_async_event(ctrl, NVME_AER_TYPE_NOTICE,
                              NVME_AER_NOTICE_DISC_CHANGED, NVME_LOG_DISC);
}

void nvmet_port_disc_changed(struct nvmet_port *port,
                             struct nvmet_subsys *subsys)
{
        struct nvmet_ctrl *ctrl;

        lockdep_assert_held(&nvmet_config_sem);
        nvmet_genctr++;

        mutex_lock(&nvmet_disc_subsys->lock);
        list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
                if (subsys && !nvmet_host_allowed(subsys, ctrl->hostnqn))
                        continue;

                __nvmet_disc_changed(port, ctrl);
        }
        mutex_unlock(&nvmet_disc_subsys->lock);

        /* If transport can signal change, notify transport */
        if (port->tr_ops && port->tr_ops->discovery_chg)
                port->tr_ops->discovery_chg(port);
}

static void __nvmet_subsys_disc_changed(struct nvmet_port *port,
                                        struct nvmet_subsys *subsys,
                                        struct nvmet_host *host)
{
        struct nvmet_ctrl *ctrl;

        mutex_lock(&nvmet_disc_subsys->lock);
        list_for_each_entry(ctrl, &nvmet_disc_subsys->ctrls, subsys_entry) {
                if (host && strcmp(nvmet_host_name(host), ctrl->hostnqn))
                        continue;

                __nvmet_disc_changed(port, ctrl);
        }
        mutex_unlock(&nvmet_disc_subsys->lock);
}

void nvmet_subsys_disc_changed(struct nvmet_subsys *subsys,
                               struct nvmet_host *host)
{
        struct nvmet_port *port;
        struct nvmet_subsys_link *s;

        nvmet_genctr++;

        list_for_each_entry(port, nvmet_ports, global_entry)
                list_for_each_entry(s, &port->subsystems, entry) {
                        if (s->subsys != subsys)
                                continue;
                        __nvmet_subsys_disc_changed(port, subsys, host);
                }
}

void nvmet_referral_enable(struct nvmet_port *parent, struct nvmet_port *port)
{
        down_write(&nvmet_config_sem);
        if (list_empty(&port->entry)) {
                list_add_tail(&port->entry, &parent->referrals);
                port->enabled = true;
                nvmet_port_disc_changed(parent, NULL);
        }
        up_write(&nvmet_config_sem);
}

void nvmet_referral_disable(struct nvmet_port *parent, struct nvmet_port *port)
{
        down_write(&nvmet_config_sem);
        if (!list_empty(&port->entry)) {
                port->enabled = false;
                list_del_init(&port->entry);
                nvmet_port_disc_changed(parent, NULL);
        }
        up_write(&nvmet_config_sem);
}

static void nvmet_format_discovery_entry(struct nvmf_disc_rsp_page_hdr *hdr,
                struct nvmet_port *port, char *subsys_nqn, char *traddr,
                u8 type, u32 numrec)
{
        struct nvmf_disc_rsp_page_entry *e = &hdr->entries[numrec];

        e->trtype = port->disc_addr.trtype;
        e->adrfam = port->disc_addr.adrfam;
        e->treq = port->disc_addr.treq;
        e->portid = port->disc_addr.portid;
        /* we support only dynamic controllers */
        e->cntlid = cpu_to_le16(NVME_CNTLID_DYNAMIC);
        e->asqsz = cpu_to_le16(NVME_AQ_DEPTH);
        e->subtype = type;
        memcpy(e->trsvcid, port->disc_addr.trsvcid, NVMF_TRSVCID_SIZE);
        memcpy(e->traddr, traddr, NVMF_TRADDR_SIZE);
        memcpy(e->tsas.common, port->disc_addr.tsas.common, NVMF_TSAS_SIZE);
        strncpy(e->subnqn, subsys_nqn, NVMF_NQN_SIZE);
}

/*
 * nvmet_set_disc_traddr - set a correct discovery log entry traddr
 *
 * IP based transports (e.g RDMA) can listen on "any" ipv4/ipv6 addresses
 * (INADDR_ANY or IN6ADDR_ANY_INIT). The discovery log page traddr reply
 * must not contain that "any" IP address. If the transport implements
 * .disc_traddr, use it. this callback will set the discovery traddr
 * from the req->port address in case the port in question listens
 * "any" IP address.
 */
static void nvmet_set_disc_traddr(struct nvmet_req *req, struct nvmet_port *port,
                char *traddr)
{
        if (req->ops->disc_traddr)
                req->ops->disc_traddr(req, port, traddr);
        else
                memcpy(traddr, port->disc_addr.traddr, NVMF_TRADDR_SIZE);
}

static size_t discovery_log_entries(struct nvmet_req *req)
{
        struct nvmet_ctrl *ctrl = req->sq->ctrl;
        struct nvmet_subsys_link *p;
        struct nvmet_port *r;
        size_t entries = 0;

        list_for_each_entry(p, &req->port->subsystems, entry) {
                if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
                        continue;
                entries++;
        }
        list_for_each_entry(r, &req->port->referrals, entry)
                entries++;
        return entries;
}

static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
{
        const int entry_size = sizeof(struct nvmf_disc_rsp_page_entry);
        struct nvmet_ctrl *ctrl = req->sq->ctrl;
        struct nvmf_disc_rsp_page_hdr *hdr;
        u64 offset = nvmet_get_log_page_offset(req->cmd);
        size_t data_len = nvmet_get_log_page_len(req->cmd);
        size_t alloc_len;
        struct nvmet_subsys_link *p;
        struct nvmet_port *r;
        u32 numrec = 0;
        u16 status = 0;
        void *buffer;

        if (!nvmet_check_transfer_len(req, data_len))
                return;

        if (req->cmd->get_log_page.lid != NVME_LOG_DISC) {
                req->error_loc =
                        offsetof(struct nvme_get_log_page_command, lid);
                status = NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
                goto out;
        }

        /* Spec requires dword aligned offsets */
        if (offset & 0x3) {
                status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
                goto out;
        }

        /*
         * Make sure we're passing at least a buffer of response header size.
         * If host provided data len is less than the header size, only the
         * number of bytes requested by host will be sent to host.
         */
        down_read(&nvmet_config_sem);
        alloc_len = sizeof(*hdr) + entry_size * discovery_log_entries(req);
        buffer = kzalloc(alloc_len, GFP_KERNEL);
        if (!buffer) {
                up_read(&nvmet_config_sem);
                status = NVME_SC_INTERNAL;
                goto out;
        }

        hdr = buffer;
        list_for_each_entry(p, &req->port->subsystems, entry) {
                char traddr[NVMF_TRADDR_SIZE];

                if (!nvmet_host_allowed(p->subsys, ctrl->hostnqn))
                        continue;

                nvmet_set_disc_traddr(req, req->port, traddr);
                nvmet_format_discovery_entry(hdr, req->port,
                                p->subsys->subsysnqn, traddr,
                                NVME_NQN_NVME, numrec);
                numrec++;
        }

        list_for_each_entry(r, &req->port->referrals, entry) {
                nvmet_format_discovery_entry(hdr, r,
                                NVME_DISC_SUBSYS_NAME,
                                r->disc_addr.traddr,
                                NVME_NQN_DISC, numrec);
                numrec++;
        }

        hdr->genctr = cpu_to_le64(nvmet_genctr);
        hdr->numrec = cpu_to_le64(numrec);
        hdr->recfmt = cpu_to_le16(0);

        nvmet_clear_aen_bit(req, NVME_AEN_BIT_DISC_CHANGE);

        up_read(&nvmet_config_sem);

        status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len);
        kfree(buffer);
out:
        nvmet_req_complete(req, status);
}

static void nvmet_execute_disc_identify(struct nvmet_req *req)
{
        struct nvmet_ctrl *ctrl = req->sq->ctrl;
        struct nvme_id_ctrl *id;
        const char model[] = "Linux";
        u16 status = 0;

        if (!nvmet_check_transfer_len(req, NVME_IDENTIFY_DATA_SIZE))
                return;

        if (req->cmd->identify.cns != NVME_ID_CNS_CTRL) {
                req->error_loc = offsetof(struct nvme_identify, cns);
                status = NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
                goto out;
        }

        id = kzalloc(sizeof(*id), GFP_KERNEL);
        if (!id) {
                status = NVME_SC_INTERNAL;
                goto out;
        }

        memset(id->sn, ' ', sizeof(id->sn));
        bin2hex(id->sn, &ctrl->subsys->serial,
                min(sizeof(ctrl->subsys->serial), sizeof(id->sn) / 2));
        memset(id->fr, ' ', sizeof(id->fr));
        memcpy_and_pad(id->mn, sizeof(id->mn), model, sizeof(model) - 1, ' ');
        memcpy_and_pad(id->fr, sizeof(id->fr),
                       UTS_RELEASE, strlen(UTS_RELEASE), ' ');

        /* no limit on data transfer sizes for now */
        id->mdts = 0;
        id->cntlid = cpu_to_le16(ctrl->cntlid);
        id->ver = cpu_to_le32(ctrl->subsys->ver);
        id->lpa = (1 << 2);

        /* no enforcement soft-limit for maxcmd - pick arbitrary high value */
        id->maxcmd = cpu_to_le16(NVMET_MAX_CMD);

        id->sgls = cpu_to_le32(1 << 0); /* we always support SGLs */
        if (ctrl->ops->flags & NVMF_KEYED_SGLS)
                id->sgls |= cpu_to_le32(1 << 2);
        if (req->port->inline_data_size)
                id->sgls |= cpu_to_le32(1 << 20);

        id->oaes = cpu_to_le32(NVMET_DISC_AEN_CFG_OPTIONAL);

        strlcpy(id->subnqn, ctrl->subsys->subsysnqn, sizeof(id->subnqn));

        status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));

        kfree(id);
out:
        nvmet_req_complete(req, status);
}

static void nvmet_execute_disc_set_features(struct nvmet_req *req)
{
        u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
        u16 stat;

        if (!nvmet_check_transfer_len(req, 0))
                return;

        switch (cdw10 & 0xff) {
        case NVME_FEAT_KATO:
                stat = nvmet_set_feat_kato(req);
                break;
        case NVME_FEAT_ASYNC_EVENT:
                stat = nvmet_set_feat_async_event(req,
                                                  NVMET_DISC_AEN_CFG_OPTIONAL);
                break;
        default:
                req->error_loc =
                        offsetof(struct nvme_common_command, cdw10);
                stat = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
                break;
        }

        nvmet_req_complete(req, stat);
}

static void nvmet_execute_disc_get_features(struct nvmet_req *req)
{
        u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10);
        u16 stat = 0;

        if (!nvmet_check_transfer_len(req, 0))
                return;

        switch (cdw10 & 0xff) {
        case NVME_FEAT_KATO:
                nvmet_get_feat_kato(req);
                break;
        case NVME_FEAT_ASYNC_EVENT:
                nvmet_get_feat_async_event(req);
                break;
        default:
                req->error_loc =
                        offsetof(struct nvme_common_command, cdw10);
                stat = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
                break;
        }

        nvmet_req_complete(req, stat);
}

u16 nvmet_parse_discovery_cmd(struct nvmet_req *req)
{
        struct nvme_command *cmd = req->cmd;

        if (unlikely(!(req->sq->ctrl->csts & NVME_CSTS_RDY))) {
                pr_err("got cmd %d while not ready\n",
                       cmd->common.opcode);
                req->error_loc =
                        offsetof(struct nvme_common_command, opcode);
                return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
        }

        switch (cmd->common.opcode) {
        case nvme_admin_set_features:
                req->execute = nvmet_execute_disc_set_features;
                return 0;
        case nvme_admin_get_features:
                req->execute = nvmet_execute_disc_get_features;
                return 0;
        case nvme_admin_async_event:
                req->execute = nvmet_execute_async_event;
                return 0;
        case nvme_admin_keep_alive:
                req->execute = nvmet_execute_keep_alive;
                return 0;
        case nvme_admin_get_log_page:
                req->execute = nvmet_execute_disc_get_log_page;
                return 0;
        case nvme_admin_identify:
                req->execute = nvmet_execute_disc_identify;
                return 0;
        default:
                pr_err("unhandled cmd %d\n", cmd->common.opcode);
                req->error_loc = offsetof(struct nvme_common_command, opcode);
                return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
        }

}

int __init nvmet_init_discovery(void)
{
        nvmet_disc_subsys =
                nvmet_subsys_alloc(NVME_DISC_SUBSYS_NAME, NVME_NQN_DISC);
        return PTR_ERR_OR_ZERO(nvmet_disc_subsys);
}

void nvmet_exit_discovery(void)
{
        nvmet_subsys_put(nvmet_disc_subsys);
}