CODEWITHSUNDEEP
c++csockets
csteifel
csteifel

Reputation: 2934

Finding sockaddr info before reading udp

Is there anyway that I can get the sockaddr information from an incoming packet without actually doing a recvfrom on the data first? I was just wondering cause you can tell that there is something to be read with like a poll or select I was wondering if I can pull more information from this before actually reading the data that was sent. I ask this because I have a system where each individual ip/port combination has its own little internal buffer that we put chunked messages into and I need to know so that I can put it in the right internal buffer.

Upvotes: 1

Views: 88

Answers (1)

Captain Obvlious
Captain Obvlious

Reputation: 20063

Yes, by supplying the MSG_PEEK flag to the recvfrom call.

recvfrom(socket, buffer, 1, MSG_PEEK, &address, &address_len);

This will leave the datagram intact and not remove it. You can of course specify a smaller value for the buffer size to reduce unecessary read overhead. The next time you do a normal recvfrom the datagram will be removed as normal.

recvfrom(socket, buffer, length, 0, &address, &address_len); // Do the actual read

Upvotes: 1

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