COAP-TLS-ENGINE-C(5)

📦
version 4.3.5b · 7 versions
, in alpine 3.24

🦋 coap-tls-engine-conf — the CoAP TLS ENGINE config file format 💅

ok so real talk, this is page COAP-TLS-ENGINE-C(5) from the File Formats Manual — it's the glow-up guide for the CoAP TLS ENGINE configuration file, and honestly bestie, it's shorter than you think and it eats. let's get into it ✨

✨ NAME ✨

coap-tls-engine-conf — literally the configuration file format for the CoAP TLS ENGINE. that's it, that's the name, she's iconic 🎀

🌸 DESCRIPTION 🌸

so the TLS ENGINE configuration file gets read in and installed when you use the -q tls_engine_conf_file option for the coap-client(5) or coap-server(5) executables. once it's in, your client or server can use the TLS ENGINE you defined to do all the appropriate TLS functions. main character energy fr 💅

NOTE: rn only OpenSSL is supported. that's the whole vibe check, no other engines are invited to this party 🙈

it also gets read in, parsed, and installed by coap_tls_engine_configure(3) — same energy, different entrance.

and here's a cute detail: this configuration file can totally be a configuration held in memory. the formatting of the memory region is the same as it would be for a file, like as if the file was mapped into memory. coap_tls_engine_configure(3) is the one that uses the memory version of the file. slay 🫶

🧚 the actual format, bestie

the configuration file comprises a set of keywords, one per line. each keyword has a parameter, with an optional second parameter. very demure, very mindful.

the format of each line is one of these (colon separated, don't forget the colons):

keyword:parameter_1:parameter_2
keyword:parameter_1

for parameter_2, this can be a zero length string. but ⚠️ if the preceding character to parameter_2 is not a colon, then parameter_2 is treated as NULL — that's exactly what's happening in the second example up there. so mind your colons, girlies.

the keywords and parameters are case sensitive. yes, fr fr, casing matters, this is not a drill 😭

if a line starts with a #, then it's treated as a comment line and it just gets ignored. empty lines are also valid and ignored. she's low maintenance like that 💖

👑 the possible keywords

  • engine — parameter_1 contains the ENGINE name (ID). parameter_2 is ignored. that's the whole job, she's simple and she knows it.
  • pre-cmd — parameter_1 is the command that's issued to the ENGINE logic before the ENGINE is initialized. if the command has a parameter, this is passed in from parameter_2. some commands do not have a parameter_2, which is usually enforced by the ENGINE — so don't try it, she will clock you 💀
  • post-cmd — parameter_1 is the command that's issued to the ENGINE logic after the ENGINE is initialized. if the command has a parameter, this is passed in from parameter_2. same deal: some commands do not have a parameter_2, usually enforced by the ENGINE.
  • enable-methods — parameter_1 is the numeric value of the or'd set of required ENGINE_METHOD_* or ENGINE_METHOD_ALL. parameter_1 can be an ascii representation of a number, or formatted as 0xXXXX. parameter_2 is ignored. bitwise realness 🌈

💜 EXAMPLE TLS ENGINE CONFIGURATION FILE 💜

here's the whole thing in action, keep it exactly as-is:

# Define the engine name
engine:pkcs11

# Define which methods are to be enabled
enable-methods:0xffff

# Define any post initialization commands
post-cmd:PIN:1234

see how post-cmd:PIN:1234 is doing the two-parameter thing? yeah. that's the moment. 🍓

⭐ SEE ALSO ⭐

go read these next, i'm obsessed with cross-referencing:

🎀 FURTHER INFORMATION 🎀

see

"RFC7252: The Constrained Application Protocol (CoAP)"

for further information. iykyk 📚

💀 BUGS 💀

found something broken? please raise an issue on GitHub at https://github.com/obgm/libcoap/issues to report any bugs. we need to know, bestie 😭

and if you've got a fix? please raise a Pull Request at https://github.com/obgm/libcoap/pulls for any fixes. be the change you want to see in the repo 🫶

🌸 AUTHORS 🌸

the libcoap project <libcoap-developers@lists.sourceforge.net> — the actual icons who made all this happen 👑

and that's the page, babe 💖 this was coap-tls-engine-conf, version 4.3, dated 04/28/2026, living her best life in the COAP-TLS-ENGINE-C(5) slot under the File Formats Manual. go configure something cute. mwah 🧚✨

📦 where this page comes from