In this part, we will start to play with ASN.1 and asn1c – installing open source ASN.1 compiler, asn1c, writing ANS.1 description of Itevad and then compiling. Please note we will not cover detailed grammar of ASN.1 or how to install asn1c into your machine. All these info could be found from Lev’s website: http://lionet.info/asn1c/blog/ Here we go:)
/* Install and make sure ASN.1 compiler work */ [root@localhost ItevadBin]# which asn1c /usr/local/bin/asn1c [root@localhost ItevadBin]# asn1c -h ASN.1 Compiler, v0.9.21 Copyright (c) 2003, 2004, 2005, 2006 Lev Walkin <vlm@lionet.info> Usage: asn1c [options] file ... Options: -E Run only the ASN.1 parser and print out the tree -F During -E operation, also perform tree fixing -P Concatenate and print the compiled text -R Restrict output (tables only, no support code) -S <dir> Directory with support (skeleton?) files (Default is "/usr/local/share/asn1c") -X Generate and print the XML DTD -Werror Treat warnings as errors; abort if any warning -Wdebug-lexer Enable verbose debugging output from lexer -Wdebug-fixer --//-- semantics processor -Wdebug-compiler --//-- compiler -fbless-SIZE Allow SIZE() constraint for INTEGER etc (non-std.) -fcompound-names Disambiguate C's struct NAME's inside top-level types -findirect-choice Compile members of CHOICE as indirect pointers -fknown-extern-type=<name> Pretend the specified type is known -fnative-types Use "long" instead of INTEGER_t whenever possible, etc. -fno-constraints Do not generate constraint checking code -fno-include-deps Do not generate courtesy #includes for dependencies -funnamed-unions Enable unnamed unions in structures -fskeletons-copy Force copying the support files -gen-PER Generate PER support code -pdu=auto Generate PDU table (discover PDUs automatically) -print-class-matrix Print out the collected object class matrix (debug) -print-constraints Explain subtype constraints (debug) -print-lines Generate "-- #line" comments in -E output [root@localhost ItevadBin]# /* ASN.1 description for Itevad Protocol */ [root@localhost itevad2]# cat itevad.asn1 /* * Itevad - an example protocol * which is used to do nothing or nothing * Name: itevad.asn1 * dave.tian@alcatel-lucent.com * Jan 6, 2011 * http://daveti.blog.com */ ITEVAD DEFINITIONS AUTOMATIC TAGS ::= BEGIN ItevadMessage ::= SEQUENCE { version Version, ip4Address IP4Address, messageBody MessageBody } Version ::= INTEGER(0..99) IP4Address ::= SEQUENCE { address OCTET STRING (SIZE(4)), portNumber INTEGER(0..65536) OPTIONAL } MessageBody ::= CHOICE { messageRequest MessageRequest, messageReply MessageReply } MessageRequest ::= SEQUENCE { transactionId TransactionId, askContent AskContent } MessageReply ::= SEQUENCE { transactionId TransactionId, answerContent AnswerContent } TransactionId ::= INTEGER(0..4294967295) -- 32-bit unsigned integer, 0xffffffff AskContent ::= IA5String(SIZE(1..1000)) AnswerContent ::= IA5String(SIZE(1..1000)) END [root@localhost itevad2]# /* Generate structure headers and sources for encoding/decoding Binary Itevad Protocol */ [root@localhost itevad2]# asn1c -fnative-types itevad.asn1 Compiled ItevadMessage.c Compiled ItevadMessage.h Compiled Version.c Compiled Version.h Compiled IP4Address.c Compiled IP4Address.h Compiled MessageBody.c Compiled MessageBody.h Compiled MessageRequest.c Compiled MessageRequest.h Compiled MessageReply.c Compiled MessageReply.h Compiled TransactionId.c Compiled TransactionId.h Compiled AskContent.c Compiled AskContent.h Compiled AnswerContent.c Compiled AnswerContent.h Symlinked /usr/local/share/asn1c/INTEGER.h -> INTEGER.h Symlinked /usr/local/share/asn1c/NativeEnumerated.h -> NativeEnumerated.h Symlinked /usr/local/share/asn1c/IA5String.h -> IA5String.h Symlinked /usr/local/share/asn1c/IA5String.c -> IA5String.c Symlinked /usr/local/share/asn1c/INTEGER.c -> INTEGER.c Symlinked /usr/local/share/asn1c/NativeEnumerated.c -> NativeEnumerated.c Symlinked /usr/local/share/asn1c/NativeInteger.h -> NativeInteger.h Symlinked /usr/local/share/asn1c/NativeInteger.c -> NativeInteger.c Symlinked /usr/local/share/asn1c/constr_CHOICE.h -> constr_CHOICE.h Symlinked /usr/local/share/asn1c/constr_CHOICE.c -> constr_CHOICE.c Symlinked /usr/local/share/asn1c/constr_SEQUENCE.h -> constr_SEQUENCE.h Symlinked /usr/local/share/asn1c/constr_SEQUENCE.c -> constr_SEQUENCE.c Symlinked /usr/local/share/asn1c/asn_application.h -> asn_application.h Symlinked /usr/local/share/asn1c/asn_system.h -> asn_system.h Symlinked /usr/local/share/asn1c/asn_codecs.h -> asn_codecs.h Symlinked /usr/local/share/asn1c/asn_internal.h -> asn_internal.h Symlinked /usr/local/share/asn1c/OCTET_STRING.h -> OCTET_STRING.h Symlinked /usr/local/share/asn1c/OCTET_STRING.c -> OCTET_STRING.c Symlinked /usr/local/share/asn1c/BIT_STRING.h -> BIT_STRING.h Symlinked /usr/local/share/asn1c/BIT_STRING.c -> BIT_STRING.c Symlinked /usr/local/share/asn1c/asn_codecs_prim.c -> asn_codecs_prim.c Symlinked /usr/local/share/asn1c/asn_codecs_prim.h -> asn_codecs_prim.h Symlinked /usr/local/share/asn1c/ber_tlv_length.h -> ber_tlv_length.h Symlinked /usr/local/share/asn1c/ber_tlv_length.c -> ber_tlv_length.c Symlinked /usr/local/share/asn1c/ber_tlv_tag.h -> ber_tlv_tag.h Symlinked /usr/local/share/asn1c/ber_tlv_tag.c -> ber_tlv_tag.c Symlinked /usr/local/share/asn1c/ber_decoder.h -> ber_decoder.h Symlinked /usr/local/share/asn1c/ber_decoder.c -> ber_decoder.c Symlinked /usr/local/share/asn1c/der_encoder.h -> der_encoder.h Symlinked /usr/local/share/asn1c/der_encoder.c -> der_encoder.c Symlinked /usr/local/share/asn1c/constr_TYPE.h -> constr_TYPE.h Symlinked /usr/local/share/asn1c/constr_TYPE.c -> constr_TYPE.c Symlinked /usr/local/share/asn1c/constraints.h -> constraints.h Symlinked /usr/local/share/asn1c/constraints.c -> constraints.c Symlinked /usr/local/share/asn1c/xer_support.h -> xer_support.h Symlinked /usr/local/share/asn1c/xer_support.c -> xer_support.c Symlinked /usr/local/share/asn1c/xer_decoder.h -> xer_decoder.h Symlinked /usr/local/share/asn1c/xer_decoder.c -> xer_decoder.c Symlinked /usr/local/share/asn1c/xer_encoder.h -> xer_encoder.h Symlinked /usr/local/share/asn1c/xer_encoder.c -> xer_encoder.c Symlinked /usr/local/share/asn1c/per_support.h -> per_support.h Symlinked /usr/local/share/asn1c/per_support.c -> per_support.c Symlinked /usr/local/share/asn1c/per_decoder.h -> per_decoder.h Symlinked /usr/local/share/asn1c/per_decoder.c -> per_decoder.c Symlinked /usr/local/share/asn1c/per_encoder.h -> per_encoder.h Symlinked /usr/local/share/asn1c/per_encoder.c -> per_encoder.c Symlinked /usr/local/share/asn1c/converter-sample.c -> converter-sample.c Generated Makefile.am.sample [root@localhost itevad2]# rm converter-sample.c rm: remove symbolic link `converter-sample.c'? yes
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