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Top Forums Programming Raw Socket Programming - Efficient Packet Sniffer Post 302827407 by DGPickett on Friday 28th of June 2013 03:46:38 PM
Old 06-28-2013
Yes, but off to a bad start, never use a dynamic command like printf() in a tight loop when fputs() is what you want. Man Page for fputs (all Section 3) - The UNIX and Linux Forums Consider the buffer settings on stdout, if you are using FILE* i/o, might best be matched to the output media for throughput, like 1-2^^n blocks if disk subsystems are well buffered. Man Page for setvbuf (all Section 3) - The UNIX and Linux Forums Code for this has to be like Lucy on the bakery assembly line: count the cycles, almost. Consider that every call to printf involves parsing this template string for meta characters like '%' and dividing it into segments for different sorts of formatting. Now printf( "%.*s", 11, "----------\n" ) would be closer, as you are telling it the string length, but it still loses to fwrite( "----------\n", 11, 1, stdout ), although I always hate the forced multiply in fread()/fwrite(). Man Page for fwrite (all Section 3) - The UNIX and Linux Forums But at least the call only has to memcpy() the N bytes into the buffer if space is available.
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PPPOE-SNIFF(8)                                                System Manager's Manual                                               PPPOE-SNIFF(8)

NAME
pppoe-sniff - examine network for non-standard PPPoE frames SYNOPSIS
pppoe-sniff [options] DESCRIPTION
pppoe-sniff listens for likely-looking PPPoE PADR and session frames and deduces extra options required for pppoe(8) to work. Some DSL providers seem to use non-standard frame types for PPPoE frames, and/or require a certain value in the Service-Name field. It is often easier to sniff those values from a machine which can successfully connect rather than try to pry them out of the DSL provider. To use pppoe-sniff, you need two computers, a DSL modem and an Ethernet hub (not an Ethernet switch.) If the DSL modem normally connects directly to your computer's Ethernet card, connect it to the "uplink" port on the Ethernet hub. Plug two computers into normal ports on the hub. On one computer, run whatever software the DSL provider gave you on whatever operating system the DSL provider supports. On the other computer, run Linux and log in as root. On the Linux machine, put the Ethernet interface into promiscuous mode and start pppoe-sniff. If the ethernet interface is eth0, for exam- ple, type these commands: ifconfig eth0 promisc pppoe-sniff -I eth0 On the other machine, start your DSL connection as usual. After a short time, pppoe-sniff should print recommendations for the value of PPPOE_EXTRA. Set this value in /etc/ppp/pppoe.conf. If pppoe-sniff indicates that something special is required in PPPOE_EXTRA, please e- mail this to pppoe@roaringpenguin.com along with the name of your ISP and the manufacturer and model number of your DSL modem. This infor- mation will be collated and provided on the PPPoE web page for users who do not have two computers. After pppoe-sniff finishes (or you stop it if it seems hung), remember to turn off promiscuous mode: ifconfig eth0 -promisc OPTIONS
-I interface The -I option specifies the Ethernet interface to use. Under Linux, it is typically eth0 or eth1. The interface should be "up" and in promiscuous mode before you start pppoe-sniff. -V The -V option causes pppoe-sniff to print its version number and exit. BUGS
pppoe-sniff only works on Linux. AUTHORS
pppoe-sniff was written by David F. Skoll <dfs@roaringpenguin.com>. The pppoe home page is http://www.roaringpenguin.com/pppoe/. SEE ALSO
pppd(8), pppoe(8), pppoe-sniff(8), pppoe-relay(8), /usr/share/doc/pppoe/README.Debian.gz 4th Berkeley Distribution 3 July 2000 PPPOE-SNIFF(8)
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