// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS Cache Manager Service
 *
 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/ip.h>
#include "internal.h"
#include "afs_cm.h"
#include "protocol_yfs.h"

static int afs_deliver_cb_init_call_back_state(struct afs_call *);
static int afs_deliver_cb_init_call_back_state3(struct afs_call *);
static int afs_deliver_cb_probe(struct afs_call *);
static int afs_deliver_cb_callback(struct afs_call *);
static int afs_deliver_cb_probe_uuid(struct afs_call *);
static int afs_deliver_cb_tell_me_about_yourself(struct afs_call *);
static void afs_cm_destructor(struct afs_call *);
static void SRXAFSCB_CallBack(struct work_struct *);
static void SRXAFSCB_InitCallBackState(struct work_struct *);
static void SRXAFSCB_Probe(struct work_struct *);
static void SRXAFSCB_ProbeUuid(struct work_struct *);
static void SRXAFSCB_TellMeAboutYourself(struct work_struct *);

static int afs_deliver_yfs_cb_callback(struct afs_call *);

#define CM_NAME(name) \
        char afs_SRXCB##name##_name[] __tracepoint_string =     \
                "CB." #name

/*
 * CB.CallBack operation type
 */
static CM_NAME(CallBack);
static const struct afs_call_type afs_SRXCBCallBack = {
        .name           = afs_SRXCBCallBack_name,
        .deliver        = afs_deliver_cb_callback,
        .destructor     = afs_cm_destructor,
        .work           = SRXAFSCB_CallBack,
};

/*
 * CB.InitCallBackState operation type
 */
static CM_NAME(InitCallBackState);
static const struct afs_call_type afs_SRXCBInitCallBackState = {
        .name           = afs_SRXCBInitCallBackState_name,
        .deliver        = afs_deliver_cb_init_call_back_state,
        .destructor     = afs_cm_destructor,
        .work           = SRXAFSCB_InitCallBackState,
};

/*
 * CB.InitCallBackState3 operation type
 */
static CM_NAME(InitCallBackState3);
static const struct afs_call_type afs_SRXCBInitCallBackState3 = {
        .name           = afs_SRXCBInitCallBackState3_name,
        .deliver        = afs_deliver_cb_init_call_back_state3,
        .destructor     = afs_cm_destructor,
        .work           = SRXAFSCB_InitCallBackState,
};

/*
 * CB.Probe operation type
 */
static CM_NAME(Probe);
static const struct afs_call_type afs_SRXCBProbe = {
        .name           = afs_SRXCBProbe_name,
        .deliver        = afs_deliver_cb_probe,
        .destructor     = afs_cm_destructor,
        .work           = SRXAFSCB_Probe,
};

/*
 * CB.ProbeUuid operation type
 */
static CM_NAME(ProbeUuid);
static const struct afs_call_type afs_SRXCBProbeUuid = {
        .name           = afs_SRXCBProbeUuid_name,
        .deliver        = afs_deliver_cb_probe_uuid,
        .destructor     = afs_cm_destructor,
        .work           = SRXAFSCB_ProbeUuid,
};

/*
 * CB.TellMeAboutYourself operation type
 */
static CM_NAME(TellMeAboutYourself);
static const struct afs_call_type afs_SRXCBTellMeAboutYourself = {
        .name           = afs_SRXCBTellMeAboutYourself_name,
        .deliver        = afs_deliver_cb_tell_me_about_yourself,
        .destructor     = afs_cm_destructor,
        .work           = SRXAFSCB_TellMeAboutYourself,
};

/*
 * YFS CB.CallBack operation type
 */
static CM_NAME(YFS_CallBack);
static const struct afs_call_type afs_SRXYFSCB_CallBack = {
        .name           = afs_SRXCBYFS_CallBack_name,
        .deliver        = afs_deliver_yfs_cb_callback,
        .destructor     = afs_cm_destructor,
        .work           = SRXAFSCB_CallBack,
};

/*
 * route an incoming cache manager call
 * - return T if supported, F if not
 */
bool afs_cm_incoming_call(struct afs_call *call)
{
        _enter("{%u, CB.OP %u}", call->service_id, call->operation_ID);

        call->epoch = rxrpc_kernel_get_epoch(call->net->socket, call->rxcall);

        switch (call->operation_ID) {
        case CBCallBack:
                call->type = &afs_SRXCBCallBack;
                return true;
        case CBInitCallBackState:
                call->type = &afs_SRXCBInitCallBackState;
                return true;
        case CBInitCallBackState3:
                call->type = &afs_SRXCBInitCallBackState3;
                return true;
        case CBProbe:
                call->type = &afs_SRXCBProbe;
                return true;
        case CBProbeUuid:
                call->type = &afs_SRXCBProbeUuid;
                return true;
        case CBTellMeAboutYourself:
                call->type = &afs_SRXCBTellMeAboutYourself;
                return true;
        case YFSCBCallBack:
                if (call->service_id != YFS_CM_SERVICE)
                        return false;
                call->type = &afs_SRXYFSCB_CallBack;
                return true;
        default:
                return false;
        }
}

/*
 * Record a probe to the cache manager from a server.
 */
static int afs_record_cm_probe(struct afs_call *call, struct afs_server *server)
{
        _enter("");

        if (test_bit(AFS_SERVER_FL_HAVE_EPOCH, &server->flags) &&
            !test_bit(AFS_SERVER_FL_PROBING, &server->flags)) {
                if (server->cm_epoch == call->epoch)
                        return 0;

                if (!server->probe.said_rebooted) {
                        pr_notice("kAFS: FS rebooted %pU\n", &server->uuid);
                        server->probe.said_rebooted = true;
                }
        }

        spin_lock(&server->probe_lock);

        if (!test_and_set_bit(AFS_SERVER_FL_HAVE_EPOCH, &server->flags)) {
                server->cm_epoch = call->epoch;
                server->probe.cm_epoch = call->epoch;
                goto out;
        }

        if (server->probe.cm_probed &&
            call->epoch != server->probe.cm_epoch &&
            !server->probe.said_inconsistent) {
                pr_notice("kAFS: FS endpoints inconsistent %pU\n",
                          &server->uuid);
                server->probe.said_inconsistent = true;
        }

        if (!server->probe.cm_probed || call->epoch == server->cm_epoch)
                server->probe.cm_epoch = server->cm_epoch;

out:
        server->probe.cm_probed = true;
        spin_unlock(&server->probe_lock);
        return 0;
}

/*
 * Find the server record by peer address and record a probe to the cache
 * manager from a server.
 */
static int afs_find_cm_server_by_peer(struct afs_call *call)
{
        struct sockaddr_rxrpc srx;
        struct afs_server *server;

        rxrpc_kernel_get_peer(call->net->socket, call->rxcall, &srx);

        server = afs_find_server(call->net, &srx);
        if (!server) {
                trace_afs_cm_no_server(call, &srx);
                return 0;
        }

        call->server = server;
        return afs_record_cm_probe(call, server);
}

/*
 * Find the server record by server UUID and record a probe to the cache
 * manager from a server.
 */
static int afs_find_cm_server_by_uuid(struct afs_call *call,
                                      struct afs_uuid *uuid)
{
        struct afs_server *server;

        rcu_read_lock();
        server = afs_find_server_by_uuid(call->net, call->request);
        rcu_read_unlock();
        if (!server) {
                trace_afs_cm_no_server_u(call, call->request);
                return 0;
        }

        call->server = server;
        return afs_record_cm_probe(call, server);
}

/*
 * Clean up a cache manager call.
 */
static void afs_cm_destructor(struct afs_call *call)
{
        kfree(call->buffer);
        call->buffer = NULL;
}

/*
 * Abort a service call from within an action function.
 */
static void afs_abort_service_call(struct afs_call *call, u32 abort_code, int error,
                                   const char *why)
{
        rxrpc_kernel_abort_call(call->net->socket, call->rxcall,
                                abort_code, error, why);
        afs_set_call_complete(call, error, 0);
}

/*
 * The server supplied a list of callbacks that it wanted to break.
 */
static void SRXAFSCB_CallBack(struct work_struct *work)
{
        struct afs_call *call = container_of(work, struct afs_call, work);

        _enter("");

        /* We need to break the callbacks before sending the reply as the
         * server holds up change visibility till it receives our reply so as
         * to maintain cache coherency.
         */
        if (call->server) {
                trace_afs_server(call->server, atomic_read(&call->server->usage),
                                 afs_server_trace_callback);
                afs_break_callbacks(call->server, call->count, call->request);
        }

        afs_send_empty_reply(call);
        afs_put_call(call);
        _leave("");
}

/*
 * deliver request data to a CB.CallBack call
 */
static int afs_deliver_cb_callback(struct afs_call *call)
{
        struct afs_callback_break *cb;
        __be32 *bp;
        int ret, loop;

        _enter("{%u}", call->unmarshall);

        switch (call->unmarshall) {
        case 0:
                afs_extract_to_tmp(call);
                call->unmarshall++;

                /* extract the FID array and its count in two steps */
                /* fall through */
        case 1:
                _debug("extract FID count");
                ret = afs_extract_data(call, true);
                if (ret < 0)
                        return ret;

                call->count = ntohl(call->tmp);
                _debug("FID count: %u", call->count);
                if (call->count > AFSCBMAX)
                        return afs_protocol_error(call, -EBADMSG,
                                                  afs_eproto_cb_fid_count);

                call->buffer = kmalloc(array3_size(call->count, 3, 4),
                                       GFP_KERNEL);
                if (!call->buffer)
                        return -ENOMEM;
                afs_extract_to_buf(call, call->count * 3 * 4);
                call->unmarshall++;

                /* Fall through */
        case 2:
                _debug("extract FID array");
                ret = afs_extract_data(call, true);
                if (ret < 0)
                        return ret;

                _debug("unmarshall FID array");
                call->request = kcalloc(call->count,
                                        sizeof(struct afs_callback_break),
                                        GFP_KERNEL);
                if (!call->request)
                        return -ENOMEM;

                cb = call->request;
                bp = call->buffer;
                for (loop = call->count; loop > 0; loop--, cb++) {
                        cb->fid.vid     = ntohl(*bp++);
                        cb->fid.vnode   = ntohl(*bp++);
                        cb->fid.unique  = ntohl(*bp++);
                }

                afs_extract_to_tmp(call);
                call->unmarshall++;

                /* extract the callback array and its count in two steps */
                /* fall through */
        case 3:
                _debug("extract CB count");
                ret = afs_extract_data(call, true);
                if (ret < 0)
                        return ret;

                call->count2 = ntohl(call->tmp);
                _debug("CB count: %u", call->count2);
                if (call->count2 != call->count && call->count2 != 0)
                        return afs_protocol_error(call, -EBADMSG,
                                                  afs_eproto_cb_count);
                call->iter = &call->def_iter;
                iov_iter_discard(&call->def_iter, READ, call->count2 * 3 * 4);
                call->unmarshall++;

                /* Fall through */
        case 4:
                _debug("extract discard %zu/%u",
                       iov_iter_count(call->iter), call->count2 * 3 * 4);

                ret = afs_extract_data(call, false);
                if (ret < 0)
                        return ret;

                call->unmarshall++;
        case 5:
                break;
        }

        if (!afs_check_call_state(call, AFS_CALL_SV_REPLYING))
                return afs_io_error(call, afs_io_error_cm_reply);

        /* we'll need the file server record as that tells us which set of
         * vnodes to operate upon */
        return afs_find_cm_server_by_peer(call);
}

/*
 * allow the fileserver to request callback state (re-)initialisation
 */
static void SRXAFSCB_InitCallBackState(struct work_struct *work)
{
        struct afs_call *call = container_of(work, struct afs_call, work);

        _enter("{%p}", call->server);

        if (call->server)
                afs_init_callback_state(call->server);
        afs_send_empty_reply(call);
        afs_put_call(call);
        _leave("");
}

/*
 * deliver request data to a CB.InitCallBackState call
 */
static int afs_deliver_cb_init_call_back_state(struct afs_call *call)
{
        int ret;

        _enter("");

        afs_extract_discard(call, 0);
        ret = afs_extract_data(call, false);
        if (ret < 0)
                return ret;

        /* we'll need the file server record as that tells us which set of
         * vnodes to operate upon */
        return afs_find_cm_server_by_peer(call);
}

/*
 * deliver request data to a CB.InitCallBackState3 call
 */
static int afs_deliver_cb_init_call_back_state3(struct afs_call *call)
{
        struct afs_uuid *r;
        unsigned loop;
        __be32 *b;
        int ret;

        _enter("");

        _enter("{%u}", call->unmarshall);

        switch (call->unmarshall) {
        case 0:
                call->buffer = kmalloc_array(11, sizeof(__be32), GFP_KERNEL);
                if (!call->buffer)
                        return -ENOMEM;
                afs_extract_to_buf(call, 11 * sizeof(__be32));
                call->unmarshall++;

                /* Fall through */
        case 1:
                _debug("extract UUID");
                ret = afs_extract_data(call, false);
                switch (ret) {
                case 0:         break;
                case -EAGAIN:   return 0;
                default:        return ret;
                }

                _debug("unmarshall UUID");
                call->request = kmalloc(sizeof(struct afs_uuid), GFP_KERNEL);
                if (!call->request)
                        return -ENOMEM;

                b = call->buffer;
                r = call->request;
                r->time_low                     = b[0];
                r->time_mid                     = htons(ntohl(b[1]));
                r->time_hi_and_version          = htons(ntohl(b[2]));
                r->clock_seq_hi_and_reserved    = ntohl(b[3]);
                r->clock_seq_low                = ntohl(b[4]);

                for (loop = 0; loop < 6; loop++)
                        r->node[loop] = ntohl(b[loop + 5]);

                call->unmarshall++;

        case 2:
                break;
        }

        if (!afs_check_call_state(call, AFS_CALL_SV_REPLYING))
                return afs_io_error(call, afs_io_error_cm_reply);

        /* we'll need the file server record as that tells us which set of
         * vnodes to operate upon */
        return afs_find_cm_server_by_uuid(call, call->request);
}

/*
 * allow the fileserver to see if the cache manager is still alive
 */
static void SRXAFSCB_Probe(struct work_struct *work)
{
        struct afs_call *call = container_of(work, struct afs_call, work);

        _enter("");
        afs_send_empty_reply(call);
        afs_put_call(call);
        _leave("");
}

/*
 * deliver request data to a CB.Probe call
 */
static int afs_deliver_cb_probe(struct afs_call *call)
{
        int ret;

        _enter("");

        afs_extract_discard(call, 0);
        ret = afs_extract_data(call, false);
        if (ret < 0)
                return ret;

        if (!afs_check_call_state(call, AFS_CALL_SV_REPLYING))
                return afs_io_error(call, afs_io_error_cm_reply);
        return afs_find_cm_server_by_peer(call);
}

/*
 * allow the fileserver to quickly find out if the fileserver has been rebooted
 */
static void SRXAFSCB_ProbeUuid(struct work_struct *work)
{
        struct afs_call *call = container_of(work, struct afs_call, work);
        struct afs_uuid *r = call->request;

        _enter("");

        if (memcmp(r, &call->net->uuid, sizeof(call->net->uuid)) == 0)
                afs_send_empty_reply(call);
        else
                afs_abort_service_call(call, 1, 1, "K-1");

        afs_put_call(call);
        _leave("");
}

/*
 * deliver request data to a CB.ProbeUuid call
 */
static int afs_deliver_cb_probe_uuid(struct afs_call *call)
{
        struct afs_uuid *r;
        unsigned loop;
        __be32 *b;
        int ret;

        _enter("{%u}", call->unmarshall);

        switch (call->unmarshall) {
        case 0:
                call->buffer = kmalloc_array(11, sizeof(__be32), GFP_KERNEL);
                if (!call->buffer)
                        return -ENOMEM;
                afs_extract_to_buf(call, 11 * sizeof(__be32));
                call->unmarshall++;

                /* Fall through */
        case 1:
                _debug("extract UUID");
                ret = afs_extract_data(call, false);
                switch (ret) {
                case 0:         break;
                case -EAGAIN:   return 0;
                default:        return ret;
                }

                _debug("unmarshall UUID");
                call->request = kmalloc(sizeof(struct afs_uuid), GFP_KERNEL);
                if (!call->request)
                        return -ENOMEM;

                b = call->buffer;
                r = call->request;
                r->time_low                     = b[0];
                r->time_mid                     = htons(ntohl(b[1]));
                r->time_hi_and_version          = htons(ntohl(b[2]));
                r->clock_seq_hi_and_reserved    = ntohl(b[3]);
                r->clock_seq_low                = ntohl(b[4]);

                for (loop = 0; loop < 6; loop++)
                        r->node[loop] = ntohl(b[loop + 5]);

                call->unmarshall++;

        case 2:
                break;
        }

        if (!afs_check_call_state(call, AFS_CALL_SV_REPLYING))
                return afs_io_error(call, afs_io_error_cm_reply);
        return afs_find_cm_server_by_uuid(call, call->request);
}

/*
 * allow the fileserver to ask about the cache manager's capabilities
 */
static void SRXAFSCB_TellMeAboutYourself(struct work_struct *work)
{
        struct afs_call *call = container_of(work, struct afs_call, work);
        int loop;

        struct {
                struct /* InterfaceAddr */ {
                        __be32 nifs;
                        __be32 uuid[11];
                        __be32 ifaddr[32];
                        __be32 netmask[32];
                        __be32 mtu[32];
                } ia;
                struct /* Capabilities */ {
                        __be32 capcount;
                        __be32 caps[1];
                } cap;
        } reply;

        _enter("");

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

        reply.ia.uuid[0] = call->net->uuid.time_low;
        reply.ia.uuid[1] = htonl(ntohs(call->net->uuid.time_mid));
        reply.ia.uuid[2] = htonl(ntohs(call->net->uuid.time_hi_and_version));
        reply.ia.uuid[3] = htonl((s8) call->net->uuid.clock_seq_hi_and_reserved);
        reply.ia.uuid[4] = htonl((s8) call->net->uuid.clock_seq_low);
        for (loop = 0; loop < 6; loop++)
                reply.ia.uuid[loop + 5] = htonl((s8) call->net->uuid.node[loop]);

        reply.cap.capcount = htonl(1);
        reply.cap.caps[0] = htonl(AFS_CAP_ERROR_TRANSLATION);
        afs_send_simple_reply(call, &reply, sizeof(reply));
        afs_put_call(call);
        _leave("");
}

/*
 * deliver request data to a CB.TellMeAboutYourself call
 */
static int afs_deliver_cb_tell_me_about_yourself(struct afs_call *call)
{
        int ret;

        _enter("");

        afs_extract_discard(call, 0);
        ret = afs_extract_data(call, false);
        if (ret < 0)
                return ret;

        if (!afs_check_call_state(call, AFS_CALL_SV_REPLYING))
                return afs_io_error(call, afs_io_error_cm_reply);
        return afs_find_cm_server_by_peer(call);
}

/*
 * deliver request data to a YFS CB.CallBack call
 */
static int afs_deliver_yfs_cb_callback(struct afs_call *call)
{
        struct afs_callback_break *cb;
        struct yfs_xdr_YFSFid *bp;
        size_t size;
        int ret, loop;

        _enter("{%u}", call->unmarshall);

        switch (call->unmarshall) {
        case 0:
                afs_extract_to_tmp(call);
                call->unmarshall++;

                /* extract the FID array and its count in two steps */
                /* Fall through */
        case 1:
                _debug("extract FID count");
                ret = afs_extract_data(call, true);
                if (ret < 0)
                        return ret;

                call->count = ntohl(call->tmp);
                _debug("FID count: %u", call->count);
                if (call->count > YFSCBMAX)
                        return afs_protocol_error(call, -EBADMSG,
                                                  afs_eproto_cb_fid_count);

                size = array_size(call->count, sizeof(struct yfs_xdr_YFSFid));
                call->buffer = kmalloc(size, GFP_KERNEL);
                if (!call->buffer)
                        return -ENOMEM;
                afs_extract_to_buf(call, size);
                call->unmarshall++;

                /* Fall through */
        case 2:
                _debug("extract FID array");
                ret = afs_extract_data(call, false);
                if (ret < 0)
                        return ret;

                _debug("unmarshall FID array");
                call->request = kcalloc(call->count,
                                        sizeof(struct afs_callback_break),
                                        GFP_KERNEL);
                if (!call->request)
                        return -ENOMEM;

                cb = call->request;
                bp = call->buffer;
                for (loop = call->count; loop > 0; loop--, cb++) {
                        cb->fid.vid     = xdr_to_u64(bp->volume);
                        cb->fid.vnode   = xdr_to_u64(bp->vnode.lo);
                        cb->fid.vnode_hi = ntohl(bp->vnode.hi);
                        cb->fid.unique  = ntohl(bp->vnode.unique);
                        bp++;
                }

                afs_extract_to_tmp(call);
                call->unmarshall++;

        case 3:
                break;
        }

        if (!afs_check_call_state(call, AFS_CALL_SV_REPLYING))
                return afs_io_error(call, afs_io_error_cm_reply);

        /* We'll need the file server record as that tells us which set of
         * vnodes to operate upon.
         */
        return afs_find_cm_server_by_peer(call);
}