ldap - BER Encoding of a "Choice" -

-

i trying parse ldap bind request using apache harmony asn.1/ber classes (could use library, chose has apache license).

my question on encoding of "choice" in asn.1. rfc defines ldap asn.1 schema (http://www.rfc-editor.org/rfc/rfc2251.txt) gives following part bind request:

   bindrequest ::= [application 0] sequence {             version                 integer (1 .. 127),             name                    ldapdn,             authentication          authenticationchoice }      authenticationchoice ::= choice {             simple                  [0] octet string,                                      -- 1 , 2 reserved             sasl                    [3] saslcredentials }      saslcredentials ::= sequence {             mechanism               ldapstring,             credentials             octet string optional }

how choice there encoded?

i generated sample bind request using jxplorer , captured raw data sent. looks this:

00000000  30 31 02 01 01 60 2c 02  01 03 04 1b 75 69 64 3d  |01...`,.....uid=| 00000010  74 65 73 74 75 73 65 72  2c 64 63 3d 74 65 73 74  |testuser,dc=test| 00000020  2c 64 63 3d 63 6f 6d 80  0a 74 65 73 74 69 6e 67  |,dc=com..testing| 00000030  31 32 33                                          |123|

the 80 there (at offset 0x27) seems represent choice. fair enough - , (per http://en.wikipedia.org/wiki/basic_encoding_rules#ber_encoding) last bit set in order indicate it's "context specific" (i.e. defined application/protocol) how know if "simple" or "sasl" auth? indicates option of choice being used? in case looks next byte (0x0a) length of string - octetstring or of sort - don't see here indicates actual other 0x80...

i'm not sure [0] , [3] mean in choice section above. saying there 4 options options numbered 0 , 3 in use?

below can see output of openssl asn1parse command. choice members encoded using called context specific tags - means normal tag value replaced 1 specified in asn.1 definition respective item in choice. tag has value 0 implicates first item in choice selected. first choice item of type octet string. value 0 of context specific tag gives information value type. if there no context tag, normal octet string tag used. 

 0:d=0  hl=2 l=  49 cons: sequence            2:d=1  hl=2 l=   1 prim:  integer           :01  5:d=1  hl=2 l=  44 cons:  appl [ 0 ]          7:d=2  hl=2 l=   1 prim:   integer           :03 10:d=2  hl=2 l=  27 prim:   octet string      :uid=testuser,dc=test,dc=com 39:d=2  hl=2 l=  10 prim:   cont [ 0 ]

Comments

Post a Comment

Popular posts from this blog

css - Which browser returns the correct result for getBoundingClientRect of an SVG element? -

-
this svg contains rect overflows svg element: <svg id='svg' width='10' height='10'> <rect x='-10' y='-10' width='30' height='30'/> </svg> chrome 28 , opera 12 return getboundingclientrect() svg element width , height of 10. firefox 23 reports width , height of 30. correct? jsfiddle the relevant spec cssom , delegates svg spec if svg element not "have associated css layout box". haven't found definition of "having associated css layout box", correct result seem hinge on definition, getbbox returns 30x30 rect in browsers. this firefox bug fixed now, fix in firefox nightlies , should make through firefox 33 released on 14 october 2014. see bug 530985 details.
Read more

gcc - Calling fftR4() in c from assembly -

-
i trying asm fft implementation www.embeddedsignals.com work. running make gives error: undefined reference fftr4(short*, short*, int) at top of asm have .syntax unified .thumb .global fftr4 .type fftr4, %function and there #define's associate c functions arguments registers followed macros fftr4 function uses. after that, fftr4 called .thumb_func fftr4: stmfd sp!, {r4-r11, lr} mov tmp0, #0 // bit reversed counter mov tmp1, #0 .word 0xf3a2fa92 //rbit r3,r2 //rbit r,n lsl r,#3 and c code follows: void fftr4(short *y, short *x, int n); short x[512]; short y[512]; int i; void loop() { (i=0;i<512;i++) x[i]=0; (i=0;i<512;i=i+8) { x[i+0]=16384; x[i+2]=16384; x[i+4]=-16384; x[i+6]=-16384;} fftr4(y, x, 256); serialusb.println(y[128]); serialusb.println(y[129]); serialusb.println(y[384]); serialusb.println(y[385]); // expected results: //y[128]is 8191; y[129] -8190 y[
Read more

Function that returns a formatted array in VBA -

-
i have function prints excel data text file in array format following: [ ['id', 'label', 'longitude', 'latitude', 'country', 'region', 'ttl_wt_flw_thru', 'sum-of-bol-wt', 'count of wdr_ref', 'ratio'], ['aeauh', 'abu dhabi, united arab emirates', 54.3666667, 24.4666667, 'ae', 'eame', 66, 30, 8432, 281.066666666667], ['aedxb', 'dubai, united arab emirates', 55.307485, 25.271139, 'ae', 'eame', 682, 3, 8369, 2789.66666666667] ] my code writing array is: function fillsourcearray() dim long, j long, s string dim lastrow double dim s1 string 'opens file filepath = filepath & "dataarray" & ".txt" open filepath output #1 'read source data dataarray = sheets("nodes").cells(1).currentregion.value 'determine lastrow lastrow = sheets("nodes").range
Read more