getsockopt(), setsockopt() not working. socket buffer size,..

igotit
Posts: 4
Joined: Thu Jul 21, 2016 1:08 pm

getsockopt(), setsockopt() not working. socket buffer size,..

Postby igotit » Sat Jan 07, 2017 2:01 pm

Hi,

In order to get the socket buffer size, My codes call the function getsockopt() .

However, the return value is always -1, and the err msg is "Protocol not available".

the codes I used,
ESP-IDF version 1;

Code: Select all

void Init_Client_mySocket(void)
{
	struct sockaddr_in serverAddress;
	memset(&serverAddress,0,sizeof(serverAddress));

	// Create a socket client 
	int sock = socket(AF_INET, SOCK_STREAM,0);// IPPROTO_TCP);
	if (sock < 0) {
		printf("socket: %d %s", sock, strerror(errno));
		goto END;
	}
	printf("socket: %d Created OK\n", sock);

	/// socket option
	int bsize=0;
	socklen_t optlen;
	optlen = sizeof(bsize);

	int retv_gso = getsockopt(sock,SOL_SOCKET,SO_RCVBUF,&bsize,&optlen);
	printf("getsockopt retv = %d. err msg=%s\n",retv_gso,strerror(errno));
	printf("rcv Buf Size = %d\n", bsize);//
...

In order to change the socket buffer size, the function setsockopt() also returns an error.

Questions.
1. How can I get the socket buffer size ?
2. How can I set the socket buffer size ?
3. What is the default socket size ?

User avatar
kolban
Posts: 1683
Joined: Mon Nov 16, 2015 4:43 pm
Location: Texas, USA

Re: getsockopt(), setsockopt() not working. socket buffer size,..

Postby kolban » Sun Jan 08, 2017 3:31 pm

If we look at this comment dated from 2007 in the LWIP stack, we see that the ability to use SO_RCVBUF is disabled by default.

https://github.com/espressif/esp-idf/bl ... ELOG#L2343

It looks like it is enableable by changing a configuration setting in lwipopts.h. However, before doing that, I would suggest a study of the LWIP package in depth and determine what made the LWIP authors make the decision to disable it by default. They may have had some very sound reason for doing such that is specific to the implementation of LWIP.

A deeper question (for me) is the effect/goal you are trying to achieve. Personally, I've never had a need to even think about this option. I'd be very interested to understand from you what the perceived need is to change the value?
Free book on ESP32 available here: https://leanpub.com/kolban-ESP32

ESP_Angus
Posts: 2344
Joined: Sun May 08, 2016 4:11 am

Re: getsockopt(), setsockopt() not working. socket buffer size,..

Postby ESP_Angus » Mon Jan 09, 2017 12:20 am

Hi,

Thanks for your patience with this. A menuconfig option to enable SO_RCVBUF in LWIP will be merged to github master branch in the next few days.

Angus

igotit
Posts: 4
Joined: Thu Jul 21, 2016 1:08 pm

Re: getsockopt(), setsockopt() not working. socket buffer size,..

Postby igotit » Mon Jan 09, 2017 12:39 pm

Hi, kolban.

In my application (the last posting -> http://www.esp32.com/viewtopic.php?f=13&t=839 ),
I need to speed up the TCP socket throughput between two ESP32 modules.
Now I trying to adjust the socket buffer size. I guess that the maximum throughput is affected by the buffser size.
I can not find any other ways to speed up.

some examples for tunning the socket
1. http://www.onlamp.com/pub/a/onlamp/2005 ... uning.html
2. http://lwip.wikia.com/wiki/Tuning_TCP
3. http://lwip.wikia.com/wiki/Maximizing_throughput
4. http://lwip.100.n7.nabble.com/LWIP-conf ... d6963.html

p.s. thank you for ESP32 book, It's so really helpful. ^^
kolban wrote:If we look at this comment dated from 2007 in the LWIP stack, we see that the ability to use SO_RCVBUF is disabled by default.

https://github.com/espressif/esp-idf/bl ... ELOG#L2343

It looks like it is enableable by changing a configuration setting in lwipopts.h. However, before doing that, I would suggest a study of the LWIP package in depth and determine what made the LWIP authors make the decision to disable it by default. They may have had some very sound reason for doing such that is specific to the implementation of LWIP.

A deeper question (for me) is the effect/goal you are trying to achieve. Personally, I've never had a need to even think about this option. I'd be very interested to understand from you what the perceived need is to change the value?

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