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Simple socket and errno = 11, No more processes

http://esp32.io/viewtopic.php?f=13&t=38816

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Simple socket and errno = 11, No more processes

Posted: Sun Mar 10, 2024 9:55 pm
by FrankJensen
Hi forum. New here. I have programmed many years in the Arduino framework and have now switched to ESP-IDF. Platformio. But I am struggling for some days, getting a simple socket to work. No matter what I try, I can not get a response from my server. I know for sure, that the server sends a reply. The Arduino code also worked flawlessly.

My log says:
- Successfully connected
- Data sent successfully
- Failed to receive data: 11 - No more processes

It fails after the timeout. If I do not have the timeout, recv hangs forever.

This code runs in a separate thread. I have boiled down the code to this.
Any suggestions would be apreciated :roll:

I should mention, that I have also a webserver and a httpClient running.
But there should be plenty of resources.
I only send 12 bytes of data, and the reply is less than 100 bytes.
Code: [Select all] [Expand/Collapse]
  1.  
  2.         struct sockaddr_in dest_addr;
  3.         inet_pton(AF_INET, host_ip, &dest_addr.sin_addr);
  4.         dest_addr.sin_family = AF_INET;
  5.         dest_addr.sin_port = htons(PORT);
  6.         addr_family = AF_INET;
  7.         ip_protocol = IPPROTO_IP;
  8.  
  9.         int sock = socket(addr_family, SOCK_STREAM, ip_protocol);
  10.         if (sock < 0)
  11.         {
  12.             ESP_LOGE(TAG, "Unable to create socket: errno %d", errno);
  13.             break;
  14.         }
  15.         ESP_LOGI(TAG, "Socket created ");
  16.         ESP_LOGI(TAG, "Connecting to %s:%d", host_ip, PORT);
  17.  
  18.         int err = connect(sock, (struct sockaddr *)&dest_addr, sizeof(dest_addr));
  19.         if (err != 0)
  20.         {
  21.             ESP_LOGE(TAG, "Socket unable to connect: errno %d", errno);
  22.             break;
  23.         }
  24.         ESP_LOGI(TAG, "Successfully connected");
  25.  
  26.         int nSend = send(sock, sendbuffer, _len_trans, 0);
  27.  
  28.          if (nSend < 0) {
  29.                 ESP_LOGE(TAG, "Failed to send data");
  30.         }
  31.         else {
  32.              ESP_LOGI(TAG, "Data sent successfully");
  33.         }
  34.  
  35. // Set timeout for recv function
  36.          struct timeval timeout;
  37.          timeout.tv_sec = 5; // 5 second timeout
  38.          timeout.tv_usec = 0;
  39.          if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) < 0) {
  40.               ESP_LOGE(TAG, "Failed to set socket receive timeout");
  41.         }
  42.  
  43.          int bytes_received = recv(sock, _frame, _len_recv, 0);
  44.  
  45.         if (bytes_received < 0) {
  46.                ESP_LOGE(TAG, "Failed to receive data: %i - %s", errno, strerror(errno));
  47.         }
  48.         if (bytes_received == 0) {
  49.               ESP_LOGI(TAG, "Server closed connection");
  50.        }
  51.        if (bytes_received > 0) {
  52.            ESP_LOGI(TAG, "Data received successfully");
  53.        }
  54.  
  55.         if (sock != -1)
  56.         {
  57.             shutdown(sock, 0);
  58.             close(sock);
  59.         }
  60.  
GeSHi © Codebox Plus Extension

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 3:48 am
by ESP_Sprite
Hm, I've been staring at your code for a while, but I'm not seeing the issue; it looks perfectly cromulent to me.

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 5:46 am
by chegewara
Maybe try w/o this code?
struct timeval timeout;
timeout.tv_sec = 5; // 5 second timeout
timeout.tv_usec = 0;
if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) < 0) {
ESP_LOGE(TAG, "Failed to set socket receive timeout");
}

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 7:27 am
by FrankJensen
Hi chegewara.

I did try without that code, and then recv never returns.

I have also tried:
- using write instead of send (not sure what the difference)
- polling the socket before recv to make sure its available (it times out).

My webserver and httpclient is running perfectly. But when this code is enabled, after 5-10 minutes, there are no available sockets, so both webserver and httpclient hangs. So somehow its eating up sockets, even though I make sure to close every time.

When I upload my old Arduino code, it just connects, and run immediately. So the server is running.

And just now, I have tried not to start the webserver and the httpclient. This changes nothing. Maybe I should try and port this code to a complete fresh project, to see if the problem persists.....

My log looks like this (I send every 10 seconds).
*****TRYINGI (26706) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (31706) Huawei: Failed to receive data: 11 - No more processes
*****TRYINGI (36706) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (36756) Huawei: Failed to receive data: 104 - Connection reset by peer
**********TRYINGI (46756) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (51756) Huawei: Failed to receive data: 11 - No more processes
******TRYINGI (57756) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (62756) Huawei: Failed to receive data: 11 - No more processes
******TRYINGI (68756) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (73766) Huawei: Failed to receive data: 11 - No more processes
*****TRYINGI (78766) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (83766) Huawei: Failed to receive data: 11 - No more processes
******TRYINGI (89766) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (94766) Huawei: Failed to receive data: 11 - No more processes
******TRYINGI (100766) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (105766) Huawei: Failed to receive data: 11 - No more processes
******TRYINGI (111776) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
BeforeReceived: -1E (116776) Huawei: Failed to receive data: 11 - No more processes
*****TRYINGI (121776) Huawei: Data sent successfully

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 7:59 am
by FrankJensen
And even with all other webservices disables, after aprox 10 minutes

*TRYINGE (1619426) Huawei: Connection failed
*TRYINGE (1638926) Huawei: Connection failed
*TRYINGE (1658426) Huawei: Connection failed
*TRYINGE (1681426) Huawei: Connection failed
*TRYINGE (1741426) Huawei: Connection failed
*TRYINGE (1801426) Huawei: Connection failed
*TRYINGE (1861426) Huawei: Connection failed
*TRYINGE (1921426) Huawei: Connection failed
*TRYINGE (1981426) Huawei: Connection failed
*TRYINGE (2041426) Huawei: Connection failed

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 8:44 am
by ESP_Sprite
In that particular case, the issue may be lingering sockets. Sockets will stay in TIME_WAIT for a while after you close them; if you have too many of those (by making and closing many connections within a small amount of time), you might not be able to create more.

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 1:00 pm
by chegewara
Hi,
thats exactly the reason i asked you to remove this part of code.
The OP is suggesting its happening on first iteration with socket server, but its happening after some time.
Like mr Sprite said, you are exhausting sockets (on server) which you can see here

Code: Select all

Huawei: Failed to receive data: 104 - Connection reset by peer
Please try to add this, not sure if it helps thou

Code: Select all

    int opt = 1;
    setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
or close socket always when you return from the code you posted

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 1:34 pm
by FrankJensen
When I remove the timeout block, recv never returns.

Log says:
*******TRYINGI (16661) Huawei: Data sent successfully
Length: 12 - 00 00 00 00 00 06 01 03 75 30 00 23
Before

Then this thread hangs forever. It never passes the recv line. Before I sprintf in the line before recv. And the line right after recv, should be Received

Adding the SO_REUSEADDR right after creating the socket, makes no difference, thread hangs in recv.

Adding the timeout back in, still with the SO_REUSEADDR, gives same result as before - however I have not checked if it has stopped eating sockets, I am checking right now.

The Reset by peer error, I have actually only seen this one time, where I made the post. Normally it always return error 11, No more processes.

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 9:25 pm
by MicroController

Code: Select all

ESP_LOGI(TAG, "Data sent successfully");
is not quite accurate ;-)
At this point, the data is not sent successfully but placed into the IP stack's buffer. Normally that's not much of a difference, but if you look into the lwIP configuration in menuconfig you may find that, by default, lwIP is set to retry sending a packet ('segment') every 60 seconds ("maximum segment lifetime") up to 12 times before giving up. So if for some reason your data doesn't make it to the other end and/or the ACK is never received, you 1) will not know for about 12 minutes and 2) will have a 'zombie' socket for that period, or until you close it.

TL;DR: The data you send apparently never makes it to the other end, and hence the other end never responds.

Re: Simple socket and errno = 11, No more processes

Posted: Mon Mar 11, 2024 9:32 pm
by FrankJensen
OK, thats some usefull information. So even though the send responds with the correct amount of bytes, it only means that they have been delivered to the buffer. How can I find out, why its not sent?

How can I send it? Do I somehow need to flush it?

Since the Arduino version is working, I dont expect it to be a server nor a reply problem. But if the data is never sent, of course there is no reply...
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