/*

 * Copyright (c) 2022 Sippy Software, Inc., http://www.sippysoft.com

 *

 * 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/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <stdatomic.h>

#include <stdbool.h>

#include <stddef.h>

#include <stdint.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <srtp2/srtp.h>

#include "config_pp.h"

#include "rtpp_types.h"

#include "rtpp_debug.h"

#include "rtpp_module.h"

#include "rtpp_module_wthr.h"

#include "rtpp_module_cplane.h"

#include "rtpp_log.h"

#include "rtpp_log_obj.h"

#include "rtpp_codeptr.h"

#include "rtpp_refcnt.h"

#include "rtpp_cfg.h"

#include "rtpp_wi.h"

#include "rtpp_wi_sgnl.h"

#include "rtpp_wi_data.h"

#include "rtpp_queue.h"

#include "rtpp_stream.h"

#include "rtp.h"

#include "rtpp_time.h"

#include "rtp_packet.h"

#include "rtpp_packetops.h"

#include "rtpp_command.h"

#include "rtpp_command_args.h"

#include "rtpp_command_sub.h"

#include "rtpp_util.h"

#include "rtpp_socket.h"

#include "rtpp_sessinfo.h"

#include "rtpp_session.h"

#include "rtpp_stats.h"

#include "rtpp_stream.h"

#include "rtpp_pipe.h"

#include "rtpp_proc_async.h"

#include "rtpp_ttl.h"

#include "rtpp_util.h"

#include "rtpp_pcount.h"

#include "rtpp_pcnt_strm.h"

#include "rtpp_linker_set.h"

#include "advanced/packet_processor.h"

#include "advanced/pproc_manager.h"

#include "rtpp_dtls.h"

#include "rtpp_dtls_util.h"

#include "rtpp_dtls_conn.h"

struct rtpp_module_priv {

    struct rtpp_dtls *dtls_ctx;

    const struct rtpp_cfg *cfsp;

    struct rtpp_minfo *mself;

};

struct dtls_gw_stream_cfg {

    struct rtpp_refcnt *rcnt;

    struct rtpp_dtls_conn *dtls_conn;

    struct rtpp_minfo *mself;

};

enum rtpp_dtls_dir {

    DTLS_IN, SRTP_IN, RTP_OUT

};

struct rtpp_dtls_gw_aux {

    enum rtpp_dtls_dir direction;

    struct rtpp_dtls_conn *dtls_conn;

    struct rtpp_minfo *mself;

};

struct wipkt {

    struct pkt_proc_ctx pktx;

    struct rtpp_dtls_gw_aux edata;

};

static struct rtpp_module_priv *rtpp_dtls_gw_ctor(const struct rtpp_cfg *,

  struct rtpp_minfo *);

static void rtpp_dtls_gw_dtor(struct rtpp_module_priv *);

static void rtpp_dtls_gw_worker(const struct rtpp_wthrdata *);

static int rtpp_dtls_gw_handle_command(struct rtpp_module_priv *,

  const struct rtpp_subc_ctx *);

static int rtpp_dtls_gw_taste_encrypted(struct pkt_proc_ctx *);

static int rtpp_dtls_gw_taste_plain(struct pkt_proc_ctx *);

static struct pproc_act rtpp_dtls_gw_enqueue(const struct pkt_proc_ctx *);

#ifdef RTPP_CHECK_LEAKS

#include "rtpp_memdeb_internal.h"

RTPP_MEMDEB_APP_STATIC;

#endif

const struct rtpp_minfo RTPP_MOD_SELF = {

    .descr.name = "dtls_gw",

    .descr.ver = MI_VER_INIT(),

    .descr.module_id = 4,

    .proc.ctor = rtpp_dtls_gw_ctor,

    .proc.dtor = rtpp_dtls_gw_dtor,

    .wapi = &(const struct rtpp_wthr_handlers){

        .main_thread = rtpp_dtls_gw_worker,

        .queue_size = RTPQ_MEDIUM_CB_LEN,

    },

    .capi = &(const struct rtpp_cplane_handlers){.ul_subc_handle = rtpp_dtls_gw_handle_command},

    .fn = &(struct rtpp_minfo_fset){0},

#ifdef RTPP_CHECK_LEAKS

    .memdeb_p = &MEMDEB_SYM

#endif

};

#if defined(LIBRTPPROXY)

DATA_SET(rtpp_modules, RTPP_MOD_SELF);

#endif

static void

rtpp_dtls_gw_worker(const struct rtpp_wthrdata *wp)

{

    struct rtpp_wi *wi;

    struct wipkt *wip;

    struct res_loc res;

    for (;;) {

        wi = rtpp_queue_get_item(wp->mod_q, 0);

        if (wi == wp->sigterm) {

            RTPP_OBJ_DECREF(wi);

            break;

        }

        wip = rtpp_wi_data_get_ptr(wi, sizeof(*wip), sizeof(*wip));

        struct rtpp_dtls_gw_aux *edp = &wip->edata;

        switch (edp->direction) {

        case DTLS_IN:

#if 0

            RTPP_LOG(edp->mself->log, RTPP_LOG_DBUG, "Packet from DTLS");

#endif

            CALL_SMETHOD(edp->dtls_conn, dtls_recv, wip->pktx.pktp);

            res = RES_HERE(1);

            break;

        case SRTP_IN:

#if 0

            RTPP_LOG(RTPP_MOD_SELF.log, RTPP_LOG_DBUG, "DTLS: packet SRTP->RTP");

#endif

            res = CALL_SMETHOD(edp->dtls_conn, srtp_recv, &wip->pktx);

            break;

        case RTP_OUT:

#if 0

            RTPP_LOG(RTPP_MOD_SELF.log, RTPP_LOG_DBUG, "DTLS: packet RTP->SRTP");

#endif

            res = CALL_SMETHOD(edp->dtls_conn, rtp_send, &wip->pktx);

            break;

        default:

            abort();

        }

        if (res.v != 0) {

            switch (edp->direction) {

            case DTLS_IN:

                break;

            case SRTP_IN:

                CALL_SMETHOD(wip->pktx.strmp_in->pcnt_strm, reg_pktin, wip->pktx.pktp);

                /* Fallthrouth */

            case RTP_OUT:

                CALL_SMETHOD(wip->pktx.strmp_in->pcount, reg_drop, res.loc);

                CALL_SMETHOD(wip->pktx.strmp_in->pproc_manager, reg_drop);

                break;

            }

            RTPP_OBJ_DECREF(wip->pktx.pktp);

        }

        RTPP_OBJ_DECREF(wi);

    }

}

static struct dtls_gw_stream_cfg *

dtls_gw_data_ctor(struct rtpp_module_priv *pvt, struct rtpp_stream *dtls_strmp)

{

    struct dtls_gw_stream_cfg *rtps_c;

    rtps_c = mod_rzmalloc(sizeof(*rtps_c), offsetof(struct dtls_gw_stream_cfg, rcnt));

    if (rtps_c == NULL) {

        goto e0;

    }

    rtps_c->dtls_conn = CALL_METHOD(pvt->dtls_ctx, newconn, dtls_strmp);

    if (rtps_c->dtls_conn == NULL) {

        goto e1;

    }

    rtps_c->mself = pvt->mself;

    RC_INCREF(pvt->mself->super_rcnt);

    RTPP_OBJ_DTOR_ATTACH_RC(rtps_c, pvt->mself->super_rcnt);

    RTPP_OBJ_DTOR_ATTACH_RC(rtps_c, rtps_c->dtls_conn->rcnt);

    RTPP_OBJ_DTOR_ATTACH(rtps_c, GET_SMETHOD(rtps_c->dtls_conn, godead),

      rtps_c->dtls_conn);

    rtps_c->mself = pvt->mself;

    return (rtps_c);

e1:

    mod_free(rtps_c);

e0:

    return (NULL);

}

static int

rtpp_dtls_gw_setup_sender(struct rtpp_module_priv *pvt,

  struct rtpp_session *spa, struct rtpp_stream *dtls_strmp)

{

    int sidx, lport;

    struct rtpp_socket *fd, *fds[2];

    fd = CALL_SMETHOD(dtls_strmp, get_skt, HEREVAL);

    if (fd != NULL) {

        RTPP_OBJ_DECREF(fd);

        return (0);

    }

    if (spa->rtp->stream[0] == dtls_strmp) {

        sidx = 0;

    } else if (spa->rtp->stream[1] == dtls_strmp) {

        sidx = 1;

    } else {

        abort();

    }

    if (rtpp_create_listener(pvt->cfsp, dtls_strmp->laddr, &lport, fds) == -1)

        return (-1);

    CALL_SMETHOD(pvt->cfsp->sessinfo, append, spa, sidx, fds);

    CALL_METHOD(pvt->cfsp->rtpp_proc_cf, nudge);

    RTPP_OBJ_DECREF(fds[0]);

    RTPP_OBJ_DECREF(fds[1]);

    dtls_strmp->port = lport;

    spa->rtcp->stream[sidx]->port = lport + 1;

    if (spa->complete == 0) {

        CALL_SMETHOD(pvt->cfsp->rtpp_stats, updatebyname, "nsess_complete", 1);

        CALL_SMETHOD(spa->rtp->stream[0]->ttl, reset_with,

          pvt->cfsp->max_ttl);

        CALL_SMETHOD(spa->rtp->stream[1]->ttl, reset_with,

          pvt->cfsp->max_ttl);

    }

    spa->complete = 1;

    return (0);

}

enum rdg_cmd {RDG_CMD_A, RDG_CMD_P, RDG_CMD_S, RDG_CMD_D, RDG_CMD_U};

static int

rtpp_dtls_gw_handle_command(struct rtpp_module_priv *pvt,

  const struct rtpp_subc_ctx *ctxp)

{

    struct dtls_gw_stream_cfg *rtps_c;

    enum rtpp_dtls_mode my_mode;

    struct rdc_peer_spec rdfs, *rdfsp;

    const rtpp_str_t * argv = rtpp_str_fix(&ctxp->subc_args->v[1]);

    int argc = ctxp->subc_args->c - 1;

    struct rtpp_stream *dtls_strmp;

    int rlen;

    char *rcp;

    enum rdg_cmd rdg_cmd;

    if (argc != 1 && argc != 3 && argc != 4) {

        RTPP_LOG(pvt->mself->log, RTPP_LOG_ERR, "expected 1, 3 or 4 parameters: %d",

          argc);

        return (-1);

    }

    switch (argv[0].s[0] | argv[0].s[1]) {

    case 'a':

    case 'A':

        if (argc != 3 && argc != 4)

            goto invalmode;

        rdfs.peer_mode = RTPP_DTLS_ACTIVE;

        rdg_cmd = RDG_CMD_A;

        break;

    case 'p':

    case 'P':

        if (argc != 3 && argc != 4)

            goto invalmode;

        rdfs.peer_mode = RTPP_DTLS_PASSIVE;

        rdg_cmd = RDG_CMD_P;

        break;

    case 's':

    case 'S':

        if (argc != 1)

            goto invalmode;

        rdg_cmd = RDG_CMD_S;

        break;

    case 'd':

    case 'D':

        if (argc != 1)

            goto invalmode;

        rdg_cmd = RDG_CMD_D;

        break;

    case 'u':

    case 'U':

        if (argc != 1)

            goto invalmode;

        rdg_cmd = RDG_CMD_U;

        break;

    default:

        goto invalmode;

    }

    switch (rdg_cmd) {

    case RDG_CMD_A:

    case RDG_CMD_P:

        if (argv[1].len > sizeof(rdfs.alg_buf))

            goto invalalg;

        for (int i = 0; i < argv[1].len; i++) {

            rdfs.alg_buf[i] = argv[1].s[i];

            if (rdfs.alg_buf[i] >= 'a')

                rdfs.alg_buf[i] -= ('a' - 'A');

        }

        rdfs.algorithm.len = argv[1].len;

        rdfs.algorithm.s = rdfs.alg_buf;

        rdfs.fingerprint = &argv[2];

        rdfs.ssrc = (argc == 4) ? &argv[3] : NULL;

        rdfsp = &rdfs;

        /* Fallthrough */

    case RDG_CMD_D:

        dtls_strmp = ctxp->strmp_in;

        break;

    case RDG_CMD_S:

        rdfsp = NULL;

        /* Fallthrough */

    case RDG_CMD_U:

        dtls_strmp = ctxp->strmp_out;

        break;

    }

    struct packet_processor_if dtls_in_poi;

    int lookup_res = CALL_SMETHOD(dtls_strmp->pproc_manager, lookup, pvt, &dtls_in_poi);

    if (lookup_res != 0) {

        rtps_c = dtls_in_poi.arg;

    }

    if (rdg_cmd == RDG_CMD_D || rdg_cmd == RDG_CMD_U) {

        if (lookup_res == 0) {

            return (-1);

        }

        CALL_SMETHOD(dtls_strmp->pproc_manager, unreg, pvt);

        CALL_SMETHOD(dtls_strmp->pproc_manager->reverse, unreg, pvt + 1);

        goto out;

    }

    if (lookup_res == 0) {

        rtps_c = dtls_gw_data_ctor(pvt, dtls_strmp);

        if (rtps_c == NULL) {

            return (-1);

        }

    }

    if (rdfsp != NULL && rdfs.peer_mode == RTPP_DTLS_PASSIVE) {

        if (rtpp_dtls_gw_setup_sender(pvt, ctxp->sessp, dtls_strmp) != 0) {

            goto e0;

        }

    }

    my_mode = CALL_SMETHOD(rtps_c->dtls_conn, setmode, rdfsp);

    if (my_mode == RTPP_DTLS_MODERR) {

        goto e0;

    }

    if (lookup_res == 0) {

        dtls_in_poi = (struct packet_processor_if){

            .descr = "dtls (srtp->rtp)",

            .taste = rtpp_dtls_gw_taste_encrypted,

            .enqueue = rtpp_dtls_gw_enqueue,

            .key = pvt,

            .arg = rtps_c,

            .rcnt = rtps_c->rcnt

        };

        if (CALL_SMETHOD(dtls_strmp->pproc_manager, reg, PPROC_ORD_DECRYPT, &dtls_in_poi) < 0) {

            goto e0;

        }

        const struct packet_processor_if dtls_out_poi = {

            .descr = "dtls (rtp->srtp)",

            .taste = rtpp_dtls_gw_taste_plain,

            .enqueue = rtpp_dtls_gw_enqueue,

            .key = pvt + 1,

            .arg = rtps_c,

            .rcnt = rtps_c->rcnt

        };

        if (CALL_SMETHOD(dtls_strmp->pproc_manager->reverse, reg, PPROC_ORD_ENCRYPT, &dtls_out_poi) < 0) {

            goto e1;

        }

    }

    if (rdfsp == NULL) {

        rcp = ctxp->resp->buf_t;

        rlen = sizeof(ctxp->resp->buf_t);

        switch (my_mode) {

        case RTPP_DTLS_ACTPASS:

            strlcpy(rcp, "actpass ", rlen);

            rcp += strlen("actpass ");

            rlen -= strlen("actpass ");

            break;

        case RTPP_DTLS_ACTIVE:

            strlcpy(rcp, "active ", rlen);

            rcp += strlen("active ");

            rlen -= strlen("active ");

            break;

        case RTPP_DTLS_PASSIVE:

            strlcpy(rcp, "passive ", rlen);

            rcp += strlen("passive ");

            rlen -= strlen("passive ");

            break;

        default:

            abort();

        }

        strlcpy(rcp, pvt->dtls_ctx->fingerprint, rlen);

    }

out:

    RTPP_OBJ_DECREF(rtps_c);

    return (0);

invalalg:

    RTPP_LOG(pvt->mself->log, RTPP_LOG_ERR, "invalid algorithm: \"%s\"",

      argv[1].s);

    return (-1);

invalmode:

    RTPP_LOG(pvt->mself->log, RTPP_LOG_ERR, "invalid mode: \"%s\"",

      argv[0].s);

    return (-1);

e1:

    CALL_SMETHOD(dtls_strmp->pproc_manager, unreg, pvt);

e0:

    RTPP_OBJ_DECREF(rtps_c);

    return (-1);

}

static int

rtpp_dtls_gw_taste_encrypted(struct pkt_proc_ctx *pktxp)

{

    struct dtls_gw_stream_cfg *rtps_c;

    static __thread struct rtpp_dtls_gw_aux dtls_in = {.direction = DTLS_IN};

    static __thread struct rtpp_dtls_gw_aux strp_in = {.direction = SRTP_IN};

    struct rtpp_dtls_gw_aux *rdgap;

    if (!rtpp_is_dtls_tst(pktxp))

        rdgap = &strp_in;

    else

        rdgap = &dtls_in;

    rtps_c = pktxp->pproc->arg;

    rdgap->dtls_conn = rtps_c->dtls_conn;

    rdgap->mself = rtps_c->mself;

    pktxp->auxp = rdgap;

    return (1);

}

static int

rtpp_dtls_gw_taste_plain(struct pkt_proc_ctx *pktxp)

{

    struct dtls_gw_stream_cfg *rtps_c;

    static __thread struct rtpp_dtls_gw_aux rtp_out = {.direction = RTP_OUT};

    if (pktxp->strmp_out == NULL)

        return (0);

    rtps_c = pktxp->pproc->arg;

    rtp_out.dtls_conn = rtps_c->dtls_conn;

    rtp_out.mself = rtps_c->mself;

    pktxp->auxp = &rtp_out;

    return (1);

}

static struct pproc_act

rtpp_dtls_gw_enqueue(const struct pkt_proc_ctx *pktxp)

{

    struct rtpp_dtls_gw_aux *edata;

    struct rtpp_wi *wi;

    struct wipkt *wip;

    edata = (struct rtpp_dtls_gw_aux *)pktxp->auxp;

    wi = rtpp_wi_malloc_udata((void **)&wip, sizeof(struct wipkt));

    if (wi == NULL)

        return (PPROC_ACT_DROP);

    wip->edata = *edata;

    RTPP_OBJ_BORROW(wi, edata->dtls_conn);

    wip->pktx = *pktxp;

    wip->pktx.rsp = NULL;

    RTPP_OBJ_BORROW(wi, pktxp->strmp_in);

    if (pktxp->strmp_out != NULL)

        RTPP_OBJ_BORROW(wi, pktxp->strmp_out);

    if (rtpp_queue_put_item(wi, edata->mself->wthr.mod_q) != 0) {

        RTPP_OBJ_DECREF(wi);

        return (PPROC_ACT_DROP);

    }

    return (PPROC_ACT_TAKE);

}

static struct rtpp_module_priv *

rtpp_dtls_gw_ctor(const struct rtpp_cfg *cfsp, struct rtpp_minfo *mself)

{

    struct rtpp_module_priv *pvt;

    static int srtp_inited = 0;

    pvt = mod_zmalloc(sizeof(struct rtpp_module_priv));

    if (pvt == NULL) {

        goto e0;

    }

    pvt->dtls_ctx = rtpp_dtls_ctor(cfsp, mself);

    if (pvt->dtls_ctx == NULL) {

        goto e1;

    }

    if (!srtp_inited && srtp_init() != 0) {

        goto e2;

    }

    srtp_inited = 1;

    pvt->cfsp = cfsp;

    pvt->mself = mself;

    return (pvt);

e2:

    RTPP_OBJ_DECREF(pvt->dtls_ctx);

e1:

    mod_free(pvt);

e0:

    return (NULL);

}

static void

rtpp_dtls_gw_dtor(struct rtpp_module_priv *pvt)

{

    srtp_shutdown();

    RTPP_OBJ_DECREF(pvt->dtls_ctx);

    mod_free(pvt);

    return;

}