sockets - How to set "don't fragment" flag bit for TCP packet in Go? -

-

i intend set "don't fragment" flag bit in go, same thing this post while in c. checked constant list didn't find option. corresponding option in go?

thanks in advance!

how set "don't fragment" flag bit tcp packet in go?

first should know tcp doesn't ip fragments. if not major implementations avoid fragmentation tcp segments using path mtu discovery.

the tl;dr typical ip packet containing tcp segment has df bit set. can (and should) try out. here sniffing few seconds of traffic between machine , stackoverflow.com:

% tshark -w /tmp/tcp.pcap tcp , host stackoverflow.com <wait few seconds> % tshark -r /tmp/tcp.pcap -t fields -e ip.flags | sort | uniq -c     186 0x00000002

0x02 means df bit set. confess in other captures have seen occasional tcp segment in ip packet without df bit; suspect rfc1191 has explanation this.

now question, think there's no portable way set df bit , more widespread question (there isn't posix-portable way). there (likely) escape hatch in relevant package implementation under golang.org/x/sys.

for example, on unix supports ip_dontfrag such freebsd 1 use unix.setsockoptint , dig relevant constant value.

on linux there not ip_dontfrag, discovered the question linked. workaround seems to use ip_mtu_discover happens available a constant in unix package. can use same unix.setsockoptint set it.


Comments

Post a Comment

Popular posts from this blog

wordpress - (T_ENDFOREACH) php error -

-
creating wordpress website , i'm getting following php error: parse error: syntax error, unexpected 'endforeach' (t_endforeach) in /home/soralmedia/public_html/wp-content/themes/soral media/woocommerce/myaccount/my-orders.php on line 98 here's code file: <?php /** * orders * * shows recent orders on account page. * * template can overridden copying yourtheme/woocommerce/myaccount/my-orders.php. * * however, on occasion woocommerce need update template files , (the theme developer). * need copy new files theme maintain compatibility. try this. * little possible, happen. when occurs version of template file will. * bumped , readme list important changes. * * @see http://docs.woothemes.com/document/template-structure/ * @author woothemes * @package woocommerce/templates * @version 2.5.0 */ if ( ! defined( 'abspath' ) ) { exit; } $my_orders_columns = apply_filters( 'woocommerce_my_account_my_orders_columns', array(
Read more

Export Excel workseet into txt file using vba - (text and numbers with formulas) -

-
i new vba have developed code use in excel move text/numbers txt file. issue have 3 functions need go same txt file. when run first function has set fs = createobject("scripting.filesystemobject") set = fs.createtextfile(module1.nys45uploadfilename, true) a.writeline (str) a.close. the other 2 functions had save. set fs = createobject("scripting.filesystemobject") set = fs.savetextfile(module1.nys45uploadfilename, true) a.writeline (str) a.close. the first function go txt file, other 2 error object doesn't support property or method. when changed 3 create last function goes txt file. can not figure out word use in order make other 2 functions follow txt file in order keyed. the entire code follows private sub addrecord_click() on error goto errhandler module1.nys45uploadfilename = application.getsaveasfilename(filefilter:="textfiles (*.txt), *.txt") if module1.nys45uploadfilename = "false" exit sub
Read more

Using django-mptt to get only the categories that have items -

-
sample structure: all uppercase: category mixed case: item root ├── books │   ├── fiction │   │   └── classics │   └── non-fiction ├── clothing └── electronics ├── laptops ├── phones │   ├── apple │   │   ├── iphone 6 │   │   ├── iphone 6 plus │   │   ├── iphone 6s │   │   └── iphone 6s plus │   ├── motorola │   │   ├── moto g4 │   │   ├── moto g4 play │   │   ├── moto g4 plus │   │   └── moto x │   └── samsung └── tablets └── apple i'm trying have index page show "electronics" category. "clothing" category shouldn't show since it's empty , "books" category shouldn't show either since, although has child categories, child categories don't have items. similarly, "electronics" page should show "phones" category. "laptops" category shouldn't show since it's empty , "tablets" category shouldn't show either since
Read more