rtpw can not receive data in srtp 1.4.4

[openluopworld]

Hi, I use srtp 1.4.4 in Ubuntu 14.04. After compiling, I execute the program rtpw with the example in libSRTP 1.4.4 Overview and Reference Manual. It can send data, but nothing can be received. Here are the steps.

1. Compile

   ./configure
   make

2. get the key

   ./crypto/test/rand_gen -n 30
   9a390d7e4c1b5abf91a523dbf987cbc981a5f40c8e319cebe35091834067

3. Then I send data and the result is below.

   ./test/rtpw -s -k 9a390d7e4c1b5abf91a523dbf987cbc981a5f40c8e319cebe35091834067 -e -a 0.0.0.0 9999
   security services: confidentiality message authentication
   set master key/salt to 9a390d7e4c1b5abf91a523dbf987cbc9/81a5f40c8e319cebe35091834067
   sending word: A
   sending word: A's
   sending word: AA's
   sending word: AB's
   sending word: ABM's
   sending word: AC's
   ...

4. But nothing received when I try to execute the following command in another shell.

   ./test/rtpw -r -k 9a390d7e4c1b5abf91a523dbf987cbc981a5f40c8e319cebe35091834067 -e -a 0.0.0.0 9999
   security services: confidentiality message authentication
   set master key/salt to 9a390d7e4c1b5abf91a523dbf987cbc9/81a5f40c8e319cebe35091834067

   Does someone know the reason or do I miss something? Thanks.

[paulej]

I assume you figured it out?

[openluopworld]

Yeah, since the function rtp_recvfrom returns an unsigned int. It can not be compared with -1.

unsigned int rtp_recvfrom(rtp_receiver_t receiver, void *msg, int *len);

// line 473 of rtpw.c in version 1.4.4
if (rtp_recvfrom(rcvr, word, &len) > -1) {