c++ - udp packet fragmentation for raw sockets -

-

follow-up of question packet fragmentation raw sockets

if have raw socket implemented such:

  if ((sip_socket = socket(af_inet, sock_raw, ipproto_raw)) < 0)       {     cout << "unable create sip sockets."<< sip_socket<<" \n";     return -3;       }     if ( setsockopt(sip_socket, ipproto_ip, ip_hdrincl, &one, sizeof(one)) == -1)       {    cerr << "unable set option raw socket.\n";    return -4;       };

how can set iphdr->fragment_offset (16 bits including 3 bit flags) if have packet of size 1756 (not including ip header)?
need prepare 2 packets-one of size 1480 , of size 276, , slap ip headers on both packets?

can point example code this?

yes, need prepare 2 packets, each own ip header.

if put 1480 bytes of data in first packet , 276 in second, ip headers should identical, except these fields:

  • fragment offset: set 0 in first packet, , 1480 in second;
  • total length: set 1480 plus header length in first packet, , 276 plus header length in second packet;
  • mf flag: set 1 in first packet , 0 in second;
  • header checksum: recalculated on different headers appropriate.

Comments

Post a Comment

Popular posts from this blog

android - Spacing between the stars of a rating bar? -

-
ho can set spacing beween stars? thats ratingbar: ratingbar = (ratingbar) inflater.inflate(r.layout.ratingbar, null); ratingbar.setlayoutparams(new layoutparams(layoutparams.wrap_content, layoutparams.wrap_content)); the layout: <?xml version="1.0" encoding="utf-8"?> <ratingbar xmlns:android="http://schemas.android.com/apk/res/android" style="@style/mystyle" android:layout_alignparentright="true" android:layout_height="19dp" android:layout_width="wrap_content" android:numstars="5"> </ratingbar> the style: <style name="mystyle" parent="@android:style/widget.ratingbar"> <item name="android:progressdrawable">@drawable/android_r2_ratingstar_yellow</item> <item name="android:indeterminatedrawable">@drawable/android_r2_ratingstar_grey</item> </style> thanks, cheers you have ...
Read more

html - Instapaper-like algorithm -

-
does of algorithm extracts contents webpage? instapaper ? there 2 steps instapaper does: find main content block on page (excluding headers, footers, menus etc) from content block extract , format text to find content block (typically html block element, div containing key page text content) instapaper uses algorithm 1 used readability . can @ source of readability.js see what's going on, @ core tries find area on page highest text/link ratio, although has other simple scoring metrics (e.g. off top of head, things ratio of text commas, para elements etc) go heuristics. once have identified root node element, relevant content, you'll need format it, if want can pull node element containing text out of source document , insert yours, in reality you'll want remove existing styles , apply own, standard , feel. if want output nice text-only can use jericho's renderer . update1 : should mention else instapaper - follow 'pagination' links (...
Read more

c# - How to execute a particular part of code asynchronously in a class -

-
i creating speech recognition engine that's going respond user commands.i have created button enable , disable speech recognition per user convenience.i have used dispose() of speech engine disable speech recoginition.here code private void button1_click(object sender, routedeventargs e) { engineon = !engineon; if (engineon) { speechengine = speech.createspeechengine(); //speech class creates , returns new speech engine. speechengine.audiolevelupdated += new eventhandler<audiolevelupdatedeventargs>(speechengine_audiolevelupdated); // use system's default microphone speechengine.setinputtodefaultaudiodevice(); speechengine.loadgrammar(new dictationgrammar()); // start listening speechengine.recognizeasync(recognizemode.multiple); } else { speechclass.myengine.dispose(); } } but disposal of speech obj...
Read more