/* rtpdump.c

 *

 * Wiretap Library

 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>

 *

 * Support for RTPDump file format

 * Copyright (c) 2023 by David Perry <boolean263@protonmail.com>

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

/* The rtpdump file format is the "dump" format as generated by rtpdump from

 * <https://github.com/irtlab/rtptools>. It starts with an ASCII text header:

 *

 *      #!rtpplay1.0 source_address/port\n

 *

 * followed by a binary header:

 *

 *      typedef struct {

 *          struct timeval start;  // start of recording (GMT)

 *          uint32_t source;       // network source (multicast)

 *          uint16_t port;         // UDP port

 *      } RD_hdr_t;

 *

 * Note that the SAME source address and port are included twice in

 * this header, as seen here:

 * <https://github.com/irtlab/rtptools/blob/9356740cb0c/rtpdump.c#L189>

 *

 * Wireshark can also generate rtpdump files, but it uses DIFFERENT addresses

 * and ports in the text vs binary headers. See rtp_write_header() in

 * ui/tap-rtp-common.c -- Wireshark puts the destination address and port

 * in the text header, but the source address and port in the binary header.

 *

 * Wireshark may also generate the file with an IPv6 address in the text

 * header, whereas rtpdump only supports IPv4 here. The binary header

 * can't hold an IPv6 address without fully breaking compatibility with

 * the rtptools project, so Wireshark truncates the address.

 *

 * Either way, each packet which follows is a RTP or RTCP packet of the form

 *

 *      typedef struct {

 *          uint16_t length; // length of original packet, including header

 *          uint16_t plen;   // actual header+payload length for RTP, 0 for RTCP

 *          uint32_t offset; // ms since the start of recording

 *      } RD_packet_t;

 *

 * followed by length bytes of packet data.

 */

#include "config.h"

#include "rtpdump.h"

#include <wtap-int.h>

#include <file_wrappers.h>

#include <wsutil/exported_pdu_tlvs.h>

#include <wsutil/inet_addr.h>

#include <wsutil/nstime.h>

#include <wsutil/strtoi.h>

#include <wsutil/wslog.h>

#include <string.h>

/* NB. I've included the version string in the magic for stronger identification.

 * If we add/change version support, we'll also need to edit:

 *  - wiretap/mime_file.c

 *  - resources/freedesktop/org.wireshark.Wireshark-mime.xml

 *  - epan/dissectors/file-rtpdump.c

 */

#define RTP_MAGIC "#!rtpplay1.0 "

#define RTP_MAGIC_LEN 13

/* Reasonable maximum length for the RTP header (after the magic):

 * - WS_INET6_ADDRSTRLEN characters for a IPv6 address

 * - 1 for a slash

 * - 5 characters for a port number

 * - 1 character for a newline

 * - 4 bytes for each of start seconds, start useconds, IPv4 address

 * - 2 bytes for each of port, padding

 * and 2 bytes of fudge factor, just in case.

 */

#define RTP_HEADER_MAX_LEN 25+WS_INET6_ADDRSTRLEN

/* Reasonable buffer size for holding the Exported PDU headers:

 * - 8 bytes for the port type header

 * - 8 bytes for one port

 * - 4+EXP_PDU_TAG_IPV6_LEN for one IPv6 address

 *    (same space would hold 2 IPv4 addresses with room to spare)

 */

#define RTP_BUFFER_INIT_LEN 20+EXP_PDU_TAG_IPV6_LEN

static bool

rtpdump_read(wtap *wth, wtap_rec *rec,

               int *err, char **err_info,

               int64_t *data_offset);

static bool

rtpdump_seek_read(wtap *wth, int64_t seek_off,

                    wtap_rec *rec,

                    int *err, char **err_info);

static void

rtpdump_close(wtap *wth);

static int rtpdump_file_type_subtype = -1;

typedef union ip_addr_u {

    ws_in4_addr ipv4;

    ws_in6_addr ipv6;

} ip_addr_t;

typedef struct rtpdump_priv_s {

    Buffer epdu_headers;

    nstime_t start_time;

} rtpdump_priv_t;

void register_rtpdump(void);

wtap_open_return_val

rtpdump_open(wtap *wth, int *err, char **err_info)

{

    uint8_t buf_magic[RTP_MAGIC_LEN];

    char ch = '\0';

    rtpdump_priv_t *priv = NULL;

    ip_addr_t txt_addr;

    ws_in4_addr bin_addr;

    uint16_t txt_port = 0;

    uint16_t bin_port = 0;

    GString *header_str = NULL;

    bool is_ipv6 = false;

    bool got_ip = false;

    nstime_t start_time = NSTIME_INIT_ZERO;

    Buffer *buf;

    if (!wtap_read_bytes(wth->fh, buf_magic, RTP_MAGIC_LEN, err, err_info)) {

        return (*err == WTAP_ERR_SHORT_READ)

            ? WTAP_OPEN_NOT_MINE

            : WTAP_OPEN_ERROR;

    }

    if (strncmp(buf_magic, RTP_MAGIC, RTP_MAGIC_LEN) != 0) {

        return WTAP_OPEN_NOT_MINE;

    }

    /* Parse the text header for an IP and port. */

    header_str = g_string_sized_new(RTP_HEADER_MAX_LEN);

    do {

        if (!wtap_read_bytes(wth->fh, &ch, 1, err, err_info)) {

            g_string_free(header_str, TRUE);

            return (*err == WTAP_ERR_SHORT_READ)

                ? WTAP_OPEN_NOT_MINE

                : WTAP_OPEN_ERROR;

        }

        if (ch == '/') {

            /* Everything up to now should be an IP address */

            if (ws_inet_pton4(header_str->str, &txt_addr.ipv4)) {

                is_ipv6 = false;

            }

            else if (ws_inet_pton6(header_str->str, &txt_addr.ipv6)) {

                is_ipv6 = true;

            }

            else {

                *err = WTAP_ERR_BAD_FILE;

                *err_info = ws_strdup("rtpdump: bad IP in header text");

                g_string_free(header_str, TRUE);

                return WTAP_OPEN_ERROR;

            }

            got_ip = true;

            g_string_truncate(header_str, 0);

        }

        else if (ch == '\n') {

            if (!got_ip) {

                *err = WTAP_ERR_BAD_FILE;

                *err_info = ws_strdup("rtpdump: no IP in header text");

                g_string_free(header_str, TRUE);

                return WTAP_OPEN_ERROR;

            }

            if (!ws_strtou16(header_str->str, NULL, &txt_port)) {

                *err = WTAP_ERR_BAD_FILE;

                *err_info = ws_strdup("rtpdump: bad port in header text");

                g_string_free(header_str, TRUE);

                return WTAP_OPEN_ERROR;

            }

            break;

        }

        else if (g_ascii_isprint(ch)) {

            g_string_append_c(header_str, ch);

        }

        else {

            g_string_free(header_str, TRUE);

            return WTAP_OPEN_NOT_MINE;

        }

    } while (ch != '\n');

    g_string_free(header_str, TRUE);

    if (!got_ip || txt_port == 0) {

        *err = WTAP_ERR_BAD_FILE;

        *err_info = ws_strdup("rtpdump: bad header text");

        return WTAP_OPEN_ERROR;

    }

    /* Whether generated by rtpdump or Wireshark, the binary header

     * has the source IP and port. If the text header has an IPv6 address,

     * this address was likely truncated from an IPv6 address as well

     * and is likely inaccurate, so we will ignore it.

     */

#define FAIL G_STMT_START {              \

    return (*err == WTAP_ERR_SHORT_READ) \

        ? WTAP_OPEN_NOT_MINE             \

        : WTAP_OPEN_ERROR;               \

} G_STMT_END

    if (!wtap_read_bytes(wth->fh, &start_time.secs, 4, err, err_info)) FAIL;

    start_time.secs = g_ntohl(start_time.secs);

    if (!wtap_read_bytes(wth->fh, &start_time.nsecs, 4, err, err_info)) FAIL;

    start_time.nsecs = g_ntohl(start_time.nsecs) * 1000;

    if (!wtap_read_bytes(wth->fh, &bin_addr, 4, err, err_info)) FAIL;

    if (!wtap_read_bytes(wth->fh, &bin_port, 2, err, err_info)) FAIL;

    bin_port = g_ntohs(bin_port);

    /* Finally, padding */

    if (!wtap_read_bytes(wth->fh, NULL, 2, err, err_info)) FAIL;

#undef FAIL

    /* If we made it this far, we have all the info we need to generate

     * most of the Exported PDU headers for every packet in this stream.

     */

    priv = g_new0(rtpdump_priv_t, 1);

    priv->start_time = start_time;

    buf = &priv->epdu_headers; /* shorthand */

    ws_buffer_init(buf, RTP_BUFFER_INIT_LEN);

    wtap_buffer_append_epdu_uint(buf, EXP_PDU_TAG_PORT_TYPE, EXP_PDU_PT_UDP);

    if (is_ipv6) {

        /* File must be generated by Wireshark. Text address is IPv6 destination,

         * binary address is invalid and ignored here.

         */

        wtap_buffer_append_epdu_tag(buf, EXP_PDU_TAG_IPV6_DST, (const uint8_t *)&txt_addr.ipv6, EXP_PDU_TAG_IPV6_LEN);

        wtap_buffer_append_epdu_uint(buf, EXP_PDU_TAG_DST_PORT, txt_port);

    }

    else if (txt_addr.ipv4 == bin_addr && txt_port == bin_port) {

        /* File must be generated by rtpdump. Both addresses are IPv4 source. */

        wtap_buffer_append_epdu_tag(buf, EXP_PDU_TAG_IPV4_SRC, (const uint8_t *)&bin_addr, EXP_PDU_TAG_IPV4_LEN);

        wtap_buffer_append_epdu_uint(buf, EXP_PDU_TAG_SRC_PORT, bin_port);

    }

    else {

        /* File must be generated by Wireshark. Text is IPv4 destination,

         * binary is IPv4 source.

         */

        wtap_buffer_append_epdu_tag(buf, EXP_PDU_TAG_IPV4_DST, (const uint8_t *)&txt_addr.ipv4, EXP_PDU_TAG_IPV4_LEN);

        wtap_buffer_append_epdu_uint(buf, EXP_PDU_TAG_DST_PORT, txt_port);

        wtap_buffer_append_epdu_tag(buf, EXP_PDU_TAG_IPV4_SRC, (const uint8_t *)&bin_addr, EXP_PDU_TAG_IPV4_LEN);

        wtap_buffer_append_epdu_uint(buf, EXP_PDU_TAG_SRC_PORT, bin_port);

    }

    wth->priv              = (void *)priv;

    wth->subtype_close     = rtpdump_close;

    wth->subtype_read      = rtpdump_read;

    wth->subtype_seek_read = rtpdump_seek_read;

    wth->file_type_subtype = rtpdump_file_type_subtype;

    wth->file_encap        = WTAP_ENCAP_WIRESHARK_UPPER_PDU;

    /* Starting timestamp has microsecond precision, but delta time

     * between packets is only milliseconds.

     */

    wth->file_tsprec       = WTAP_TSPREC_MSEC;

    return WTAP_OPEN_MINE;

}

static bool

rtpdump_read_packet(wtap *wth, FILE_T fh, wtap_rec *rec,

                      int *err, char **err_info)

{

    rtpdump_priv_t *priv = (rtpdump_priv_t *)wth->priv;

    nstime_t ts = NSTIME_INIT_ZERO;

    uint32_t epdu_len = 0;       /* length of the Exported PDU headers we add */

    const uint8_t hdr_len = 8;   /* Header comprised of the following 3 fields: */

    uint16_t length;             /* length of packet, including this header (may

                                   be smaller than plen if not whole packet recorded) */

    uint16_t plen;               /* actual header+payload length for RTP, 0 for RTCP */

    uint32_t offset;             /* milliseconds since the start of recording */

    if (!wtap_read_bytes_or_eof(fh, (void *)&length, 2, err, err_info)) return false;

    length = g_ntohs(length);

    if (!wtap_read_bytes(fh, (void *)&plen, 2, err, err_info)) return false;

    plen = g_ntohs(plen);

    if (!wtap_read_bytes(fh, (void *)&offset, 4, err, err_info)) return false;

    offset = g_ntohl(offset);

    /* Set length to remaining length of packet data */

    length -= hdr_len;

    ws_buffer_append_buffer(&rec->data, &priv->epdu_headers);

    if (plen == 0) {

        /* RTCP sample */

        plen = length;

        wtap_buffer_append_epdu_string(&rec->data, EXP_PDU_TAG_DISSECTOR_NAME, "rtcp");

    }

    else {

        /* RTP sample */

        wtap_buffer_append_epdu_string(&rec->data, EXP_PDU_TAG_DISSECTOR_NAME, "rtp");

    }

    epdu_len = wtap_buffer_append_epdu_end(&rec->data);

    /* Offset is milliseconds since the start of recording */

    ts.secs = offset / 1000;

    ts.nsecs = (offset % 1000) * 1000000;

    nstime_sum(&rec->ts, &priv->start_time, &ts);

    rec->presence_flags |= WTAP_HAS_TS | WTAP_HAS_CAP_LEN;

    rec->rec_header.packet_header.caplen = epdu_len + plen;

    rec->rec_header.packet_header.len = epdu_len + length;

    rec->rec_type = REC_TYPE_PACKET;

    return wtap_read_bytes_buffer(fh, &rec->data, length, err, err_info);

}

static bool

rtpdump_read(wtap *wth, wtap_rec *rec, int *err, char **err_info,

               int64_t *data_offset)

{

    *data_offset = file_tell(wth->fh);

    return rtpdump_read_packet(wth, wth->fh, rec, err, err_info);

}

static bool

rtpdump_seek_read(wtap *wth, int64_t seek_off, wtap_rec *rec,

                    int *err, char **err_info)

{

    if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)

        return false;

    return rtpdump_read_packet(wth, wth->random_fh, rec, err, err_info);

}

static void

rtpdump_close(wtap *wth)

{

    rtpdump_priv_t *priv = (rtpdump_priv_t *)wth->priv;

    ws_buffer_free(&priv->epdu_headers);

}

static const struct supported_block_type rtpdump_blocks_supported[] = {

    /* We support packet blocks, with no comments or other options. */

    { WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED }

};

static const struct file_type_subtype_info rtpdump_info = {

    "RTPDump stream file", "rtpdump", "rtp", "rtpdump",

    false, BLOCKS_SUPPORTED(rtpdump_blocks_supported),

    NULL, NULL, NULL

};

void register_rtpdump(void)

{

    rtpdump_file_type_subtype = wtap_register_file_type_subtype(&rtpdump_info);

}