[vlc-devel] [PATCH] srt: parse srt parameters from url

Tristan Matthews tmatth at videolan.org
Wed Mar 6 16:20:07 CET 2019


On Wed, Mar 6, 2019 at 10:04 AM Aaron Boxer <boxerab at gmail.com> wrote:
>
> Thanks, Remi. Is there another better way of getting a user-configured passphrase to the srt module ?

I think you want the vlc_credential API, see e.g.,
https://git.videolan.org/?p=vlc.git;a=blob;f=modules/access/http.c;h=56d75687e27f10a6c1ef33cd32178dcc857e4136;hb=HEAD#l304

Best,
-t

> On Wed, Mar 6, 2019 at 5:57 AM Rémi Denis-Courmont <remi at remlab.net> wrote:
>>
>> Hi,
>>
>> Passing passwords in URLs is well-documented as a terrible idea. In VLC's case, the passphrase will show up in the OSD title, window title, logs, etc...
>>
>> Le 5 mars 2019 23:42:14 GMT+02:00, Aaron Boxer <boxerab at gmail.com> a écrit :
>>>
>>> Parse pass phrase and latency from url for incoming srt stream
>>>
>>>
>>> diff --git a/modules/access/srt.c b/modules/access/srt.c
>>> index d8d8cbe659..55c0efc201 100644
>>> --- a/modules/access/srt.c
>>> +++ b/modules/access/srt.c
>>> @@ -37,6 +37,9 @@
>>>
>>>  #include <srt/srt.h>
>>>
>>> +const char* SRT_PARAM_PASSPHRASE     = "passphrase";
>>> +const char* SRT_PARAM_LATENCY         = "latency";
>>> +
>>>  /* libsrt defines default packet size as 1316 internally
>>>   * so srt module takes same value. */
>>>  #define SRT_DEFAULT_CHUNK_SIZE 1316
>>> @@ -70,6 +73,85 @@ typedef struct
>>>      int         i_chunks; /* Number of chunks to allocate in the next read */
>>>  } stream_sys_t;
>>>
>>> +
>>> +
>>> +struct parsed_param {
>>> +    char *key;
>>> +    char *val;
>>> +};
>>> +
>>> +static inline char *
>>> +find(char *str, char find)
>>> +{
>>> +    str = strchr(str, find);
>>> +    if (NULL == str) {
>>> +        return NULL;
>>> +    }
>>> +    return str + 1;
>>> +}
>>> +
>>> +static inline char *
>>> +find_query(char *str)
>>> +{
>>> +    return find(str, '?');
>>> +}
>>> +
>>> +/**
>>> + * 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, char delimiter, struct parsed_param *params, int max_params)
>>> +{
>>> +    int i = 0;
>>> +
>>> +    if (!query ||  *query == '\0')
>>> +    {
>>> +        return -1;
>>> +    }
>>> +    if (!params || max_params  == 0)
>>> +    {
>>> +        return 0;
>>> +    }
>>> +
>>> +    params[i++].key = query;
>>> +    while (i < max_params && NULL != (query = strchr(query, delimiter)))
>>> +    {
>>> +        *query = '\0';
>>> +        params[i].key = ++query;
>>> +        params[i].val = NULL;
>>> +
>>> +        /* Go back and split previous param if one exists */
>>> +        if (i > 0)
>>> +        {
>>> +            if ((params[i - 1].val = strchr(params[i - 1].key, '=')) != NULL)
>>> +            {
>>> +                *(params[i - 1].val)++ = '\0';
>>> +            }
>>> +        }
>>> +        i++;
>>> +    }
>>> +    /* Go back and split last param */
>>> +    if ((params[i - 1].val = strchr(params[i - 1].key, '=')) != NULL)
>>> +    {
>>> +        *(params[i - 1].val)++ = '\0';
>>> +    }
>>> +    return i;
>>> +}
>>> +
>>> +
>>>  static void srt_wait_interrupted(void *p_data)
>>>  {
>>>      stream_t *p_stream = p_data;
>>> @@ -115,9 +197,11 @@ static int Control(stream_t *p_stream, int i_query, va_list args)
>>>
>>>  static bool srt_schedule_reconnect(stream_t *p_stream)
>>>  {
>>> -    int         i_latency;
>>> +    int         i_latency=-1;
>>>      int         stat;
>>>      char        *psz_passphrase = NULL;
>>> +    bool        parsed_passphrase = false;
>>> +    char        *url = NULL;
>>>
>>>      struct addrinfo hints = {
>>>          .ai_socktype = SOCK_DGRAM,
>>> @@ -153,6 +237,38 @@ static bool srt_schedule_reconnect(stream_t *p_stream)
>>>          goto out;
>>>      }
>>>
>>> +    /* Parse URL parameters */
>>> +    if (p_stream->psz_url && strlen(p_stream->psz_url) < 512)
>>> +    {
>>> +        char* query = NULL;
>>> +        struct parsed_param params[32];
>>> +        int num_params = 0;
>>> +        int i=0;
>>> +        size_t url_size = strlen(p_stream->psz_url)+1;
>>> +
>>> +        url = malloc(url_size);
>>> +        url[url_size-1] = 0;
>>> +        strcpy(url, p_stream->psz_url);
>>> +        query = find_query(url);
>>> +        if (query)
>>> +        {
>>> +            num_params = srt_url_parse_query(query,'&', params, sizeof(params)/sizeof(struct parsed_param) );
>>> +            if (num_params > 0) {
>>> +                for (i = 0; i < num_params; ++i)
>>> +                {
>>> +                    if (strcmp(params[i].key, SRT_PARAM_PASSPHRASE) == 0)
>>> +                    {
>>> +                        psz_passphrase = params[i].val;
>>> +                        parsed_passphrase = true;
>>> +                    }
>>> +                    else if (strcmp(params[i].key, SRT_PARAM_LATENCY) == 0)
>>> +                        i_latency = atoi(params[i].val);
>>> +                }
>>> +            }
>>> +        }
>>> +    }
>>> +
>>> +
>>>      /* Make SRT non-blocking */
>>>      srt_setsockopt( p_sys->sock, 0, SRTO_SNDSYN,
>>>          &(bool) { false }, sizeof( bool ) );
>>> @@ -168,11 +284,13 @@ static bool srt_schedule_reconnect(stream_t *p_stream)
>>>          &(int) { 0 }, sizeof( int ) );
>>>
>>>      /* Set latency */
>>> -    i_latency = var_InheritInteger( p_stream, "latency" );
>>> +    if (i_latency == -1)
>>> +        i_latency = var_InheritInteger( p_stream, SRT_PARAM_LATENCY );
>>>      srt_setsockopt( p_sys->sock, 0, SRTO_TSBPDDELAY,
>>>          &i_latency, sizeof( int ) );
>>>
>>> -    psz_passphrase = var_InheritString( p_stream, "passphrase" );
>>> +    if (!psz_passphrase)
>>> +        psz_passphrase = var_InheritString( p_stream, SRT_PARAM_PASSPHRASE );
>>>      if ( psz_passphrase != NULL && psz_passphrase[0] != '\0')
>>>      {
>>>          int i_key_length = var_InheritInteger( p_stream, "key-length" );
>>> @@ -211,7 +329,11 @@ out:
>>>      }
>>>
>>>      freeaddrinfo( res );
>>> -    free( psz_passphrase );
>>> +    if (!parsed_passphrase)
>>> +    {
>>> +        free( psz_passphrase );
>>> +    }
>>> +       free(url);
>>>
>>>      return !failed;
>>>  }
>>> @@ -422,8 +544,8 @@ vlc_module_begin ()
>>>              N_("SRT chunk size (bytes)"), NULL, true )
>>>      add_integer( "poll-timeout", SRT_DEFAULT_POLL_TIMEOUT,
>>>              N_("Return poll wait after timeout milliseconds (-1 = infinite)"), NULL, true )
>>> -    add_integer( "latency", SRT_DEFAULT_LATENCY, N_("SRT latency (ms)"), NULL, true )
>>> -    add_password("passphrase", "", N_("Password for stream encryption"), NULL)
>>> +    add_integer( SRT_PARAM_LATENCY, SRT_DEFAULT_LATENCY, N_("SRT latency (ms)"), NULL, true )
>>> +    add_password(SRT_PARAM_PASSPHRASE, "", N_("Password for stream encryption"), NULL)
>>>      add_integer( "key-length", SRT_DEFAULT_KEY_LENGTH,
>>>              SRT_KEY_LENGTH_TEXT, SRT_KEY_LENGTH_TEXT, false )
>>>          change_integer_list( srt_key_lengths, srt_key_length_names )
>>>
>>
>> --
>> Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez excuser ma brièveté.
>
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