#include <linux/ceph/ceph_debug.h>

#include <linux/module.h>
#include <linux/err.h>
#include <linux/slab.h>

#include <linux/ceph/types.h>
#include <linux/ceph/decode.h>
#include <linux/ceph/libceph.h>
#include <linux/ceph/messenger.h>
#include "auth_none.h"
#include "auth_x.h"


/*
 * get protocol handler
 */
static u32 supported_protocols[] = {
        CEPH_AUTH_NONE,
        CEPH_AUTH_CEPHX
};

static int ceph_auth_init_protocol(struct ceph_auth_client *ac, int protocol)
{
        switch (protocol) {
        case CEPH_AUTH_NONE:
                return ceph_auth_none_init(ac);
        case CEPH_AUTH_CEPHX:
                return ceph_x_init(ac);
        default:
                return -ENOENT;
        }
}

/*
 * setup, teardown.
 */
struct ceph_auth_client *ceph_auth_init(const char *name, const char *secret)
{
        struct ceph_auth_client *ac;
        int ret;

        dout("auth_init name '%s' secret '%s'\n", name, secret);

        ret = -ENOMEM;
        ac = kzalloc(sizeof(*ac), GFP_NOFS);
        if (!ac)
                goto out;

        ac->negotiating = true;
        if (name)
                ac->name = name;
        else
                ac->name = CEPH_AUTH_NAME_DEFAULT;
        dout("auth_init name %s secret %s\n", ac->name, secret);
        ac->secret = secret;
        return ac;

out:
        return ERR_PTR(ret);
}

void ceph_auth_destroy(struct ceph_auth_client *ac)
{
        dout("auth_destroy %p\n", ac);
        if (ac->ops)
                ac->ops->destroy(ac);
        kfree(ac);
}

/*
 * Reset occurs when reconnecting to the monitor.
 */
void ceph_auth_reset(struct ceph_auth_client *ac)
{
        dout("auth_reset %p\n", ac);
        if (ac->ops && !ac->negotiating)
                ac->ops->reset(ac);
        ac->negotiating = true;
}

int ceph_entity_name_encode(const char *name, void **p, void *end)
{
        int len = strlen(name);

        if (*p + 2*sizeof(u32) + len > end)
                return -ERANGE;
        ceph_encode_32(p, CEPH_ENTITY_TYPE_CLIENT);
        ceph_encode_32(p, len);
        ceph_encode_copy(p, name, len);
        return 0;
}

/*
 * Initiate protocol negotiation with monitor.  Include entity name
 * and list supported protocols.
 */
int ceph_auth_build_hello(struct ceph_auth_client *ac, void *buf, size_t len)
{
        struct ceph_mon_request_header *monhdr = buf;
        void *p = monhdr + 1, *end = buf + len, *lenp;
        int i, num;
        int ret;

        dout("auth_build_hello\n");
        monhdr->have_version = 0;
        monhdr->session_mon = cpu_to_le16(-1);
        monhdr->session_mon_tid = 0;

        ceph_encode_32(&p, 0);  /* no protocol, yet */

        lenp = p;
        p += sizeof(u32);

        ceph_decode_need(&p, end, 1 + sizeof(u32), bad);
        ceph_encode_8(&p, 1);
        num = ARRAY_SIZE(supported_protocols);
        ceph_encode_32(&p, num);
        ceph_decode_need(&p, end, num * sizeof(u32), bad);
        for (i = 0; i < num; i++)
                ceph_encode_32(&p, supported_protocols[i]);

        ret = ceph_entity_name_encode(ac->name, &p, end);
        if (ret < 0)
                return ret;
        ceph_decode_need(&p, end, sizeof(u64), bad);
        ceph_encode_64(&p, ac->global_id);

        ceph_encode_32(&lenp, p - lenp - sizeof(u32));
        return p - buf;

bad:
        return -ERANGE;
}

static int ceph_build_auth_request(struct ceph_auth_client *ac,
                                   void *msg_buf, size_t msg_len)
{
        struct ceph_mon_request_header *monhdr = msg_buf;
        void *p = monhdr + 1;
        void *end = msg_buf + msg_len;
        int ret;

        monhdr->have_version = 0;
        monhdr->session_mon = cpu_to_le16(-1);
        monhdr->session_mon_tid = 0;

        ceph_encode_32(&p, ac->protocol);

        ret = ac->ops->build_request(ac, p + sizeof(u32), end);
        if (ret < 0) {
                pr_err("error %d building auth method %s request\n", ret,
                       ac->ops->name);
                return ret;
        }
        dout(" built request %d bytes\n", ret);
        ceph_encode_32(&p, ret);
        return p + ret - msg_buf;
}

/*
 * Handle auth message from monitor.
 */
int ceph_handle_auth_reply(struct ceph_auth_client *ac,
                           void *buf, size_t len,
                           void *reply_buf, size_t reply_len)
{
        void *p = buf;
        void *end = buf + len;
        int protocol;
        s32 result;
        u64 global_id;
        void *payload, *payload_end;
        int payload_len;
        char *result_msg;
        int result_msg_len;
        int ret = -EINVAL;

        dout("handle_auth_reply %p %p\n", p, end);
        ceph_decode_need(&p, end, sizeof(u32) * 3 + sizeof(u64), bad);
        protocol = ceph_decode_32(&p);
        result = ceph_decode_32(&p);
        global_id = ceph_decode_64(&p);
        payload_len = ceph_decode_32(&p);
        payload = p;
        p += payload_len;
        ceph_decode_need(&p, end, sizeof(u32), bad);
        result_msg_len = ceph_decode_32(&p);
        result_msg = p;
        p += result_msg_len;
        if (p != end)
                goto bad;

        dout(" result %d '%.*s' gid %llu len %d\n", result, result_msg_len,
             result_msg, global_id, payload_len);

        payload_end = payload + payload_len;

        if (global_id && ac->global_id != global_id) {
                dout(" set global_id %lld -> %lld\n", ac->global_id, global_id);
                ac->global_id = global_id;
        }

        if (ac->negotiating) {
                /* server does not support our protocols? */
                if (!protocol && result < 0) {
                        ret = result;
                        goto out;
                }
                /* set up (new) protocol handler? */
                if (ac->protocol && ac->protocol != protocol) {
                        ac->ops->destroy(ac);
                        ac->protocol = 0;
                        ac->ops = NULL;
                }
                if (ac->protocol != protocol) {
                        ret = ceph_auth_init_protocol(ac, protocol);
                        if (ret) {
                                pr_err("error %d on auth protocol %d init\n",
                                       ret, protocol);
                                goto out;
                        }
                }

                ac->negotiating = false;
        }

        ret = ac->ops->handle_reply(ac, result, payload, payload_end);
        if (ret == -EAGAIN) {
                return ceph_build_auth_request(ac, reply_buf, reply_len);
        } else if (ret) {
                pr_err("auth method '%s' error %d\n", ac->ops->name, ret);
                return ret;
        }
        return 0;

bad:
        pr_err("failed to decode auth msg\n");
out:
        return ret;
}

int ceph_build_auth(struct ceph_auth_client *ac,
                    void *msg_buf, size_t msg_len)
{
        if (!ac->protocol)
                return ceph_auth_build_hello(ac, msg_buf, msg_len);
        BUG_ON(!ac->ops);
        if (ac->ops->should_authenticate(ac))
                return ceph_build_auth_request(ac, msg_buf, msg_len);
        return 0;
}

int ceph_auth_is_authenticated(struct ceph_auth_client *ac)
{
        if (!ac->ops)
                return 0;
        return ac->ops->is_authenticated(ac);
}