SSL connection via AT commands

ESP_Faye
Posts: 1646
Joined: Mon Oct 27, 2014 11:08 am

Re: SSL connection via AT commands

Postby ESP_Faye » Mon Apr 27, 2015 10:22 am

Hi, doughboy,

We debugged on your problem, it's the RAM limitation cause that.

AT commands has only 17KBytes available heap now,SSL need 12KBytes free heap size, if you espconn_secure_set_size to set 5KBytes,it is not enough..

So SSL can not be used in AT commands because RAM is limited.

Sorry for the inconvenience.

doughboy
Posts: 63
Joined: Thu Mar 05, 2015 1:54 am

Re: SSL connection via AT commands

Postby doughboy » Mon Apr 27, 2015 11:08 am

ok, thank you for the explanation.

Do you think it is still possible to optimize the firmware code some more?
v0.93SDK has no problem connecting using SSL to real websites like google and yahoo.
There is a real world need to be able to connect to SSL server, particularly for sending email or connecting to REST services. Most REST servers only accept SSL connection.

if there are 32k ram, and ssl code needs 12k, and ssl buffer size use 8k, that still leaves 12k ram for AT firmware, which is plenty. If firmware use 2k for tx and 2k for rx buffer, that still leaves 8k ram for everything else.

Thanks.

SL!M
Posts: 22
Joined: Tue Dec 30, 2014 11:17 pm

Re: SSL connection via AT commands

Postby SL!M » Thu Jun 18, 2015 2:37 am

Hi,

My question is for the Espressif team, will SSL AT command ever be supported in the future? I understand the ram issue, maybe with proper optimization this could be fixed? like reducing the size of the Tx/Rx buffer and reducing the number of connections allowed. There must be room for compromise somehow. There is no way clients will install devices on there network that doesn't support SSL or some kind of encryption.
Sure we can implement our own encryption solution or use the SDK, but we prefer an out of the box solution.

Thanks,

SL!M
Posts: 22
Joined: Tue Dec 30, 2014 11:17 pm

Re: SSL connection via AT commands

Postby SL!M » Tue Aug 11, 2015 3:23 pm

To close this topic, I was able to successfully implement SSL AT command after the 8KB optimization with v1.2.0 sdk...
I didn't fully test it yet but it works for now.
Thanks!

munderhill
Posts: 2
Joined: Tue Feb 17, 2015 4:26 am

Re: SSL connection via AT commands

Postby munderhill » Tue Aug 11, 2015 8:01 pm

SL!M, can you post the firmware?

SL!M
Posts: 22
Joined: Tue Dec 30, 2014 11:17 pm

Re: SSL connection via AT commands

Postby SL!M » Wed Aug 12, 2015 5:38 pm

Here you go, this is a rough draft and its ugly! but it will work you need to customize it to your needs. Maybe later i will clean it up and post it again.
It's tested with sdk v1.2.0 with the SSL and memory optimization patch, not tested with the latest sdk. Remember to burn the bin files:
blank ----> 0x7e000 and 0xfe000
boot ----> 0x00000
user1.1024.new.2.bin ----> 0x1000

To start the connection: AT+TEST<CR><LF>
To send some data to the server: AT+TEST=?<CR><LF>

You need to build and run axtsltest.sln in VC_TLS_demo, I made a quick modification to the server posted by this guy: viewtopic.php?f=7&t=386
(BTW thanks huafan)

Enjoy
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