vlc/modules/access/srt_common.c

/*****************************************************************************
 * srt_common.c: SRT (Secure Reliable Transport) access module
 *****************************************************************************
 *
 * Copyright (C) 2019, Haivision Systems Inc.
 *
 * Author: Aaron Boxer <aaron.boxer@collabora.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#include "srt_common.h"

const char * const srt_key_length_names[] = { N_( "16 bytes" ), N_(
        "24 bytes" ), N_( "32 bytes" ), };

typedef struct parsed_param {
    char *key;
    char *val;
} parsed_param_t;

static inline char*
find(char *str, char find)
{
    str = strchr( str, find );
    return str != NULL ? str + 1 : NULL;
}

/**
 * Parse a query string into an array of key/value structs.
 *
 * The query string should be a null terminated string of parameters separated
 * by a delimiter. Each parameter are checked for the equal sign character.
 * If it appears in the parameter, it will be used as a null terminator
 * and the part that comes after it will be the value of the parameter.
 *
 *
 * param: query:         the query string to parse. The string will be modified.
 * param: delimiter:      the character that separates the key/value pairs
 *                      from each other.
 * param: params:       an array of parsed_param structs to hold the result.
 * param: max_params:     maximum number of parameters to parse.
 *
 * Return:                the number of parsed items. -1 if there was an error.
 */
static int srt_url_parse_query(char *query, const char* delimiter,
        parsed_param_t *params, int max_params)
{
    int i = 0;
    char *token = NULL;

    if (!query || *query == '\0')
        return -1;
    if (!params || max_params == 0)
        return 0;

    token = strtok( query, delimiter );
    while (token != NULL && i < max_params) {
        params[i].key = token;
        params[i].val = NULL;
        if ((params[i].val = strchr( params[i].key, '=' )) != NULL) {
            size_t val_len = strlen( params[i].val );

            /* make key into a zero-delimited string */
            *(params[i].val) = '\0';

            /* make sure val is not empty */
            if (val_len > 1) {
                params[i].val++;

                /* make sure key is not empty */
                if (params[i].key[0])
                    i++;
            };
        }
        token = strtok( NULL, delimiter );
    }
    return i;
}

bool srt_parse_url(char* url, srt_params_t* params)
{
    char* query = NULL;
    struct parsed_param local_params[32];
    int num_params = 0;
    int i = 0;
    bool rc = false;

    if (!url || !url[0] || !params)
        return false;

    /* initialize params */
    params->latency = -1;
    params->passphrase = NULL;
    params->key_length = -1;
    params->payload_size = -1;
    params->bandwidth_overhead_limit = -1;
    params->streamid = NULL;

    /* Parse URL parameters */
    query = find( url, '?' );
    if (query) {
        num_params = srt_url_parse_query( query, "&", local_params,
                sizeof(local_params) / sizeof(struct parsed_param) );
        if (num_params > 0) {
            rc = true;
            for (i = 0; i < num_params; ++i) {
                char* val = local_params[i].val;
                if (!val)
                    continue;

                if (strcmp( local_params[i].key, SRT_PARAM_LATENCY ) == 0) {
                    int temp = atoi( val );
                    if (temp >= 0)
                        params->latency = temp;
                } else if (strcmp( local_params[i].key, SRT_PARAM_PASSPHRASE )
                        == 0) {
                    params->passphrase = val;
                } else if (strcmp( local_params[i].key, SRT_PARAM_STREAMID )
                        == 0) {
                    params->streamid = val;
                } else if (strcmp( local_params[i].key, SRT_PARAM_PAYLOAD_SIZE )
                        == 0) {
                    int temp = atoi( val );
                    if (temp >= 0)
                        params->payload_size = temp;
                } else if (strcmp( local_params[i].key, SRT_PARAM_KEY_LENGTH )
                        == 0) {
                    int temp = atoi( val );
                    if (temp == srt_key_lengths[0] || temp == srt_key_lengths[1]
                            || temp == srt_key_lengths[2]) {
                        params->key_length = temp;
                    }
                } else if (strcmp( local_params[i].key,
                SRT_PARAM_BANDWIDTH_OVERHEAD_LIMIT ) == 0) {
                    int temp = atoi( val );
                    if (temp >= 0)
                        params->bandwidth_overhead_limit = temp;

                }
            }
        }
    }

    return rc;
}

int srt_set_socket_option(vlc_object_t *this, const char *srt_param,
        SRTSOCKET u, SRT_SOCKOPT opt, const void *optval, int optlen)
{
    int stat = 0;

    stat = srt_setsockopt( u, 0, opt, optval, optlen );
    if (stat)
    msg_Err( this, "Failed to set socket option %s (reason: %s)", srt_param,
            srt_getlasterror_str() );

    return stat;
}