// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * RDMA Transport Layer
 *
 * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
 * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
 * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
 */
#undef pr_fmt
#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt

#include <linux/module.h>
#include <linux/inet.h>

#include "rtrs-pri.h"
#include "rtrs-log.h"

MODULE_DESCRIPTION("RDMA Transport Core");
MODULE_LICENSE("GPL");

struct rtrs_iu *rtrs_iu_alloc(u32 iu_num, size_t size, gfp_t gfp_mask,
                              struct ib_device *dma_dev,
                              enum dma_data_direction dir,
                              void (*done)(struct ib_cq *cq, struct ib_wc *wc))
{
        struct rtrs_iu *ius, *iu;
        int i;

        ius = kcalloc(iu_num, sizeof(*ius), gfp_mask);
        if (!ius)
                return NULL;
        for (i = 0; i < iu_num; i++) {
                iu = &ius[i];
                iu->direction = dir;
                iu->buf = kzalloc(size, gfp_mask);
                if (!iu->buf)
                        goto err;

                iu->dma_addr = ib_dma_map_single(dma_dev, iu->buf, size, dir);
                if (ib_dma_mapping_error(dma_dev, iu->dma_addr))
                        goto err;

                iu->cqe.done  = done;
                iu->size      = size;
        }
        return ius;
err:
        rtrs_iu_free(ius, dma_dev, i);
        return NULL;
}
EXPORT_SYMBOL_GPL(rtrs_iu_alloc);

void rtrs_iu_free(struct rtrs_iu *ius, struct ib_device *ibdev, u32 queue_num)
{
        struct rtrs_iu *iu;
        int i;

        if (!ius)
                return;

        for (i = 0; i < queue_num; i++) {
                iu = &ius[i];
                ib_dma_unmap_single(ibdev, iu->dma_addr, iu->size, iu->direction);
                kfree(iu->buf);
        }
        kfree(ius);
}
EXPORT_SYMBOL_GPL(rtrs_iu_free);

int rtrs_iu_post_recv(struct rtrs_con *con, struct rtrs_iu *iu)
{
        struct rtrs_sess *sess = con->sess;
        struct ib_recv_wr wr;
        struct ib_sge list;

        list.addr   = iu->dma_addr;
        list.length = iu->size;
        list.lkey   = sess->dev->ib_pd->local_dma_lkey;

        if (list.length == 0) {
                rtrs_wrn(con->sess,
                          "Posting receive work request failed, sg list is empty\n");
                return -EINVAL;
        }
        wr = (struct ib_recv_wr) {
                .wr_cqe  = &iu->cqe,
                .sg_list = &list,
                .num_sge = 1,
        };

        return ib_post_recv(con->qp, &wr, NULL);
}
EXPORT_SYMBOL_GPL(rtrs_iu_post_recv);

int rtrs_post_recv_empty(struct rtrs_con *con, struct ib_cqe *cqe)
{
        struct ib_recv_wr wr;

        wr = (struct ib_recv_wr) {
                .wr_cqe  = cqe,
        };

        return ib_post_recv(con->qp, &wr, NULL);
}
EXPORT_SYMBOL_GPL(rtrs_post_recv_empty);

static int rtrs_post_send(struct ib_qp *qp, struct ib_send_wr *head,
                          struct ib_send_wr *wr, struct ib_send_wr *tail)
{
        if (head) {
                struct ib_send_wr *next = head;

                while (next->next)
                        next = next->next;
                next->next = wr;
        } else {
                head = wr;
        }

        if (tail)
                wr->next = tail;

        return ib_post_send(qp, head, NULL);
}

int rtrs_iu_post_send(struct rtrs_con *con, struct rtrs_iu *iu, size_t size,
                       struct ib_send_wr *head)
{
        struct rtrs_sess *sess = con->sess;
        struct ib_send_wr wr;
        struct ib_sge list;

        if (WARN_ON(size == 0))
                return -EINVAL;

        list.addr   = iu->dma_addr;
        list.length = size;
        list.lkey   = sess->dev->ib_pd->local_dma_lkey;

        wr = (struct ib_send_wr) {
                .wr_cqe     = &iu->cqe,
                .sg_list    = &list,
                .num_sge    = 1,
                .opcode     = IB_WR_SEND,
                .send_flags = IB_SEND_SIGNALED,
        };

        return rtrs_post_send(con->qp, head, &wr, NULL);
}
EXPORT_SYMBOL_GPL(rtrs_iu_post_send);

int rtrs_iu_post_rdma_write_imm(struct rtrs_con *con, struct rtrs_iu *iu,
                                struct ib_sge *sge, unsigned int num_sge,
                                u32 rkey, u64 rdma_addr, u32 imm_data,
                                enum ib_send_flags flags,
                                struct ib_send_wr *head,
                                struct ib_send_wr *tail)
{
        struct ib_rdma_wr wr;
        int i;

        wr = (struct ib_rdma_wr) {
                .wr.wr_cqe        = &iu->cqe,
                .wr.sg_list       = sge,
                .wr.num_sge       = num_sge,
                .rkey             = rkey,
                .remote_addr      = rdma_addr,
                .wr.opcode        = IB_WR_RDMA_WRITE_WITH_IMM,
                .wr.ex.imm_data = cpu_to_be32(imm_data),
                .wr.send_flags  = flags,
        };

        /*
         * If one of the sges has 0 size, the operation will fail with a
         * length error
         */
        for (i = 0; i < num_sge; i++)
                if (WARN_ON(sge[i].length == 0))
                        return -EINVAL;

        return rtrs_post_send(con->qp, head, &wr.wr, tail);
}
EXPORT_SYMBOL_GPL(rtrs_iu_post_rdma_write_imm);

static int rtrs_post_rdma_write_imm_empty(struct rtrs_con *con,
                                          struct ib_cqe *cqe,
                                          u32 imm_data,
                                          struct ib_send_wr *head)
{
        struct ib_rdma_wr wr;
        struct rtrs_sess *sess = con->sess;
        enum ib_send_flags sflags;

        atomic_dec_if_positive(&con->sq_wr_avail);
        sflags = (atomic_inc_return(&con->wr_cnt) % sess->signal_interval) ?
                0 : IB_SEND_SIGNALED;

        wr = (struct ib_rdma_wr) {
                .wr.wr_cqe      = cqe,
                .wr.send_flags  = sflags,
                .wr.opcode      = IB_WR_RDMA_WRITE_WITH_IMM,
                .wr.ex.imm_data = cpu_to_be32(imm_data),
        };

        return rtrs_post_send(con->qp, head, &wr.wr, NULL);
}

static void qp_event_handler(struct ib_event *ev, void *ctx)
{
        struct rtrs_con *con = ctx;

        switch (ev->event) {
        case IB_EVENT_COMM_EST:
                rtrs_info(con->sess, "QP event %s (%d) received\n",
                           ib_event_msg(ev->event), ev->event);
                rdma_notify(con->cm_id, IB_EVENT_COMM_EST);
                break;
        default:
                rtrs_info(con->sess, "Unhandled QP event %s (%d) received\n",
                           ib_event_msg(ev->event), ev->event);
                break;
        }
}

static int create_cq(struct rtrs_con *con, int cq_vector, int nr_cqe,
                     enum ib_poll_context poll_ctx)
{
        struct rdma_cm_id *cm_id = con->cm_id;
        struct ib_cq *cq;

        cq = ib_cq_pool_get(cm_id->device, nr_cqe, cq_vector, poll_ctx);
        if (IS_ERR(cq)) {
                rtrs_err(con->sess, "Creating completion queue failed, errno: %ld\n",
                          PTR_ERR(cq));
                return PTR_ERR(cq);
        }
        con->cq = cq;
        con->nr_cqe = nr_cqe;

        return 0;
}

static int create_qp(struct rtrs_con *con, struct ib_pd *pd,
                     u32 max_send_wr, u32 max_recv_wr, u32 max_sge)
{
        struct ib_qp_init_attr init_attr = {NULL};
        struct rdma_cm_id *cm_id = con->cm_id;
        int ret;

        init_attr.cap.max_send_wr = max_send_wr;
        init_attr.cap.max_recv_wr = max_recv_wr;
        init_attr.cap.max_recv_sge = 1;
        init_attr.event_handler = qp_event_handler;
        init_attr.qp_context = con;
        init_attr.cap.max_send_sge = max_sge;

        init_attr.qp_type = IB_QPT_RC;
        init_attr.send_cq = con->cq;
        init_attr.recv_cq = con->cq;
        init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;

        ret = rdma_create_qp(cm_id, pd, &init_attr);
        if (ret) {
                rtrs_err(con->sess, "Creating QP failed, err: %d\n", ret);
                return ret;
        }
        con->qp = cm_id->qp;

        return ret;
}

int rtrs_cq_qp_create(struct rtrs_sess *sess, struct rtrs_con *con,
                       u32 max_send_sge, int cq_vector, int nr_cqe,
                       u32 max_send_wr, u32 max_recv_wr,
                       enum ib_poll_context poll_ctx)
{
        int err;

        err = create_cq(con, cq_vector, nr_cqe, poll_ctx);
        if (err)
                return err;

        err = create_qp(con, sess->dev->ib_pd, max_send_wr, max_recv_wr,
                        max_send_sge);
        if (err) {
                ib_cq_pool_put(con->cq, con->nr_cqe);
                con->cq = NULL;
                return err;
        }
        con->sess = sess;

        return 0;
}
EXPORT_SYMBOL_GPL(rtrs_cq_qp_create);

void rtrs_cq_qp_destroy(struct rtrs_con *con)
{
        if (con->qp) {
                rdma_destroy_qp(con->cm_id);
                con->qp = NULL;
        }
        if (con->cq) {
                ib_cq_pool_put(con->cq, con->nr_cqe);
                con->cq = NULL;
        }
}
EXPORT_SYMBOL_GPL(rtrs_cq_qp_destroy);

static void schedule_hb(struct rtrs_sess *sess)
{
        queue_delayed_work(sess->hb_wq, &sess->hb_dwork,
                           msecs_to_jiffies(sess->hb_interval_ms));
}

void rtrs_send_hb_ack(struct rtrs_sess *sess)
{
        struct rtrs_con *usr_con = sess->con[0];
        u32 imm;
        int err;

        imm = rtrs_to_imm(RTRS_HB_ACK_IMM, 0);
        err = rtrs_post_rdma_write_imm_empty(usr_con, sess->hb_cqe, imm,
                                             NULL);
        if (err) {
                rtrs_err(sess, "send HB ACK failed, errno: %d\n", err);
                sess->hb_err_handler(usr_con);
                return;
        }
}
EXPORT_SYMBOL_GPL(rtrs_send_hb_ack);

static void hb_work(struct work_struct *work)
{
        struct rtrs_con *usr_con;
        struct rtrs_sess *sess;
        u32 imm;
        int err;

        sess = container_of(to_delayed_work(work), typeof(*sess), hb_dwork);
        usr_con = sess->con[0];

        if (sess->hb_missed_cnt > sess->hb_missed_max) {
                rtrs_err(sess, "HB missed max reached.\n");
                sess->hb_err_handler(usr_con);
                return;
        }
        if (sess->hb_missed_cnt++) {
                /* Reschedule work without sending hb */
                schedule_hb(sess);
                return;
        }

        sess->hb_last_sent = ktime_get();

        imm = rtrs_to_imm(RTRS_HB_MSG_IMM, 0);
        err = rtrs_post_rdma_write_imm_empty(usr_con, sess->hb_cqe, imm,
                                             NULL);
        if (err) {
                rtrs_err(sess, "HB send failed, errno: %d\n", err);
                sess->hb_err_handler(usr_con);
                return;
        }

        schedule_hb(sess);
}

void rtrs_init_hb(struct rtrs_sess *sess, struct ib_cqe *cqe,
                  unsigned int interval_ms, unsigned int missed_max,
                  void (*err_handler)(struct rtrs_con *con),
                  struct workqueue_struct *wq)
{
        sess->hb_cqe = cqe;
        sess->hb_interval_ms = interval_ms;
        sess->hb_err_handler = err_handler;
        sess->hb_wq = wq;
        sess->hb_missed_max = missed_max;
        sess->hb_missed_cnt = 0;
        INIT_DELAYED_WORK(&sess->hb_dwork, hb_work);
}
EXPORT_SYMBOL_GPL(rtrs_init_hb);

void rtrs_start_hb(struct rtrs_sess *sess)
{
        schedule_hb(sess);
}
EXPORT_SYMBOL_GPL(rtrs_start_hb);

void rtrs_stop_hb(struct rtrs_sess *sess)
{
        cancel_delayed_work_sync(&sess->hb_dwork);
        sess->hb_missed_cnt = 0;
}
EXPORT_SYMBOL_GPL(rtrs_stop_hb);

static int rtrs_str_gid_to_sockaddr(const char *addr, size_t len,
                                     short port, struct sockaddr_storage *dst)
{
        struct sockaddr_ib *dst_ib = (struct sockaddr_ib *)dst;
        int ret;

        /*
         * We can use some of the IPv6 functions since GID is a valid
         * IPv6 address format
         */
        ret = in6_pton(addr, len, dst_ib->sib_addr.sib_raw, '\0', NULL);
        if (ret == 0)
                return -EINVAL;

        dst_ib->sib_family = AF_IB;
        /*
         * Use the same TCP server port number as the IB service ID
         * on the IB port space range
         */
        dst_ib->sib_sid = cpu_to_be64(RDMA_IB_IP_PS_IB | port);
        dst_ib->sib_sid_mask = cpu_to_be64(0xffffffffffffffffULL);
        dst_ib->sib_pkey = cpu_to_be16(0xffff);

        return 0;
}

/**
 * rtrs_str_to_sockaddr() - Convert rtrs address string to sockaddr
 * @addr:       String representation of an addr (IPv4, IPv6 or IB GID):
 *              - "ip:192.168.1.1"
 *              - "ip:fe80::200:5aee:feaa:20a2"
 *              - "gid:fe80::200:5aee:feaa:20a2"
 * @len:        String address length
 * @port:       Destination port
 * @dst:        Destination sockaddr structure
 *
 * Returns 0 if conversion successful. Non-zero on error.
 */
static int rtrs_str_to_sockaddr(const char *addr, size_t len,
                                u16 port, struct sockaddr_storage *dst)
{
        if (strncmp(addr, "gid:", 4) == 0) {
                return rtrs_str_gid_to_sockaddr(addr + 4, len - 4, port, dst);
        } else if (strncmp(addr, "ip:", 3) == 0) {
                char port_str[8];
                char *cpy;
                int err;

                snprintf(port_str, sizeof(port_str), "%u", port);
                cpy = kstrndup(addr + 3, len - 3, GFP_KERNEL);
                err = cpy ? inet_pton_with_scope(&init_net, AF_UNSPEC,
                                                 cpy, port_str, dst) : -ENOMEM;
                kfree(cpy);

                return err;
        }
        return -EPROTONOSUPPORT;
}

/**
 * sockaddr_to_str() - convert sockaddr to a string.
 * @addr:       the sockadddr structure to be converted.
 * @buf:        string containing socket addr.
 * @len:        string length.
 *
 * The return value is the number of characters written into buf not
 * including the trailing '\0'. If len is == 0 the function returns 0..
 */
int sockaddr_to_str(const struct sockaddr *addr, char *buf, size_t len)
{

        switch (addr->sa_family) {
        case AF_IB:
                return scnprintf(buf, len, "gid:%pI6",
                        &((struct sockaddr_ib *)addr)->sib_addr.sib_raw);
        case AF_INET:
                return scnprintf(buf, len, "ip:%pI4",
                        &((struct sockaddr_in *)addr)->sin_addr);
        case AF_INET6:
                return scnprintf(buf, len, "ip:%pI6c",
                          &((struct sockaddr_in6 *)addr)->sin6_addr);
        }
        return scnprintf(buf, len, "<invalid address family>");
}
EXPORT_SYMBOL(sockaddr_to_str);

/**
 * rtrs_addr_to_str() - convert rtrs_addr to a string "src@dst"
 * @addr:       the rtrs_addr structure to be converted
 * @buf:        string containing source and destination addr of a path
 *              separated by '@' I.e. "ip:1.1.1.1@ip:1.1.1.2"
 *              "ip:1.1.1.1@ip:1.1.1.2".
 * @len:        string length
 *
 * The return value is the number of characters written into buf not
 * including the trailing '\0'.
 */
int rtrs_addr_to_str(const struct rtrs_addr *addr, char *buf, size_t len)
{
        int cnt;

        cnt = sockaddr_to_str((struct sockaddr *)addr->src,
                              buf, len);
        cnt += scnprintf(buf + cnt, len - cnt, "@");
        sockaddr_to_str((struct sockaddr *)addr->dst,
                        buf + cnt, len - cnt);
        return cnt;
}
EXPORT_SYMBOL(rtrs_addr_to_str);

/**
 * rtrs_addr_to_sockaddr() - convert path string "src,dst" or "src@dst"
 * to sockaddreses
 * @str:        string containing source and destination addr of a path
 *              separated by ',' or '@' I.e. "ip:1.1.1.1,ip:1.1.1.2" or
 *              "ip:1.1.1.1@ip:1.1.1.2". If str contains only one address it's
 *              considered to be destination.
 * @len:        string length
 * @port:       Destination port number.
 * @addr:       will be set to the source/destination address or to NULL
 *              if str doesn't contain any source address.
 *
 * Returns zero if conversion successful. Non-zero otherwise.
 */
int rtrs_addr_to_sockaddr(const char *str, size_t len, u16 port,
                          struct rtrs_addr *addr)
{
        const char *d;

        d = strchr(str, ',');
        if (!d)
                d = strchr(str, '@');
        if (d) {
                if (rtrs_str_to_sockaddr(str, d - str, 0, addr->src))
                        return -EINVAL;
                d += 1;
                len -= d - str;
                str  = d;

        } else {
                addr->src = NULL;
        }
        return rtrs_str_to_sockaddr(str, len, port, addr->dst);
}
EXPORT_SYMBOL(rtrs_addr_to_sockaddr);

void rtrs_rdma_dev_pd_init(enum ib_pd_flags pd_flags,
                            struct rtrs_rdma_dev_pd *pool)
{
        WARN_ON(pool->ops && (!pool->ops->alloc ^ !pool->ops->free));
        INIT_LIST_HEAD(&pool->list);
        mutex_init(&pool->mutex);
        pool->pd_flags = pd_flags;
}
EXPORT_SYMBOL(rtrs_rdma_dev_pd_init);

void rtrs_rdma_dev_pd_deinit(struct rtrs_rdma_dev_pd *pool)
{
        mutex_destroy(&pool->mutex);
        WARN_ON(!list_empty(&pool->list));
}
EXPORT_SYMBOL(rtrs_rdma_dev_pd_deinit);

static void dev_free(struct kref *ref)
{
        struct rtrs_rdma_dev_pd *pool;
        struct rtrs_ib_dev *dev;

        dev = container_of(ref, typeof(*dev), ref);
        pool = dev->pool;

        mutex_lock(&pool->mutex);
        list_del(&dev->entry);
        mutex_unlock(&pool->mutex);

        if (pool->ops && pool->ops->deinit)
                pool->ops->deinit(dev);

        ib_dealloc_pd(dev->ib_pd);

        if (pool->ops && pool->ops->free)
                pool->ops->free(dev);
        else
                kfree(dev);
}

int rtrs_ib_dev_put(struct rtrs_ib_dev *dev)
{
        return kref_put(&dev->ref, dev_free);
}
EXPORT_SYMBOL(rtrs_ib_dev_put);

static int rtrs_ib_dev_get(struct rtrs_ib_dev *dev)
{
        return kref_get_unless_zero(&dev->ref);
}

struct rtrs_ib_dev *
rtrs_ib_dev_find_or_add(struct ib_device *ib_dev,
                         struct rtrs_rdma_dev_pd *pool)
{
        struct rtrs_ib_dev *dev;

        mutex_lock(&pool->mutex);
        list_for_each_entry(dev, &pool->list, entry) {
                if (dev->ib_dev->node_guid == ib_dev->node_guid &&
                    rtrs_ib_dev_get(dev))
                        goto out_unlock;
        }
        mutex_unlock(&pool->mutex);
        if (pool->ops && pool->ops->alloc)
                dev = pool->ops->alloc();
        else
                dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (IS_ERR_OR_NULL(dev))
                goto out_err;

        kref_init(&dev->ref);
        dev->pool = pool;
        dev->ib_dev = ib_dev;
        dev->ib_pd = ib_alloc_pd(ib_dev, pool->pd_flags);
        if (IS_ERR(dev->ib_pd))
                goto out_free_dev;

        if (pool->ops && pool->ops->init && pool->ops->init(dev))
                goto out_free_pd;

        mutex_lock(&pool->mutex);
        list_add(&dev->entry, &pool->list);
out_unlock:
        mutex_unlock(&pool->mutex);
        return dev;

out_free_pd:
        ib_dealloc_pd(dev->ib_pd);
out_free_dev:
        if (pool->ops && pool->ops->free)
                pool->ops->free(dev);
        else
                kfree(dev);
out_err:
        return NULL;
}
EXPORT_SYMBOL(rtrs_ib_dev_find_or_add);