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RE: ARP static entry
- From: Birahim Larou Fall <BLFall at scmmicro dot fr>
- To: "Michael Grimard" <michaelg at maxt dot com>
- Cc: ecos-discuss at sourceware dot org
- Date: Tue, 28 Mar 2006 11:11:56 +0200
- Subject: RE: [ECOS] ARP static entry
1/ The argument gateway passed to the function may not be correct
char gateway[] = {01, 10,10,10}; // to be confirm or {10,10,10,01};
Also before to call ioct() declares the routes static:
rt->rt_flags|=RTF_STATIC; // static route: added by user. This avoid the
route to be removed on timeout
Make a break point for debug in function ip_output() and follows your
packet until arp_request();
Why you want to disable this roote after interface set up?
2/UDP is connectionless but it needs a route to send data. So if it does
not know its route, IP layer uses ARP to found the route. "UDP and TCP"
can have the same route. UDP add entry to the tab.
3/ More than two network interface can share the same MAC adress but they
must have different IP adress. When IP packets arrived, data are passed
to the interface that match with IP address of the dest addr of the IP
packet. Of course the best way, since you use freebsd, is to use eth0
for redboot and eth1 for your appli with different address MAC. You should
configure the cdl file to enable eth1 if it's not done.
4/ About lwip, for me it's ok, you have just to modifie the ethernet
logical driver for lwip (eth_drv) to bypass arp:
eCos\packages\io\eth\current\src\lwip\eth_drv
hope this can help you!
PS: en utilisant lwip tu peux economiser jusqu'Ã 150Mo surtout que t'ulise
pas TCP qui represente la moitià de lwip. Si on parle pas un peu le
franÃais, on risque de se faire taper par chirac :)
Fall Birahim
Elsys Design for SCM Microsystems
Thanks Birahim.
What I'm trying to do is modify the stack so that all configuration will
be
static (no DNS and no ARP). Everything (Host name, IP Address and MAC
Address) will be known in advance and read from a configuration file to
configure the stack. My network is a closed network and it needs to be up
and running really fast after a reset, so there is no time (and need) to
use
DNS and ARP protocols. Also, I only need to use UDP packet.
The first step I thaught to do is to add a static entry to the ARP and the
next step would have been to disable it.
I used the code posted by Sebastien to add a route in ARP table, ioctl()
returns 0 (no error), show_network_tables() show me a new route for
10.10.10.90 (but the gateway is 10.10.10.90) so the route is probably not
good. The first time I send a packet to 10.10.10.90, I see the ARP request
and reply packets on the wire... That confirms that the route/entry is not
good.
I removed the code to add the entry to ARP table and call
show_network_tables() after the first packet is sent and the ARP protocol
has done is job, but I don't see the new entry (I have four entries, two
on
eth0 (0.0.0.0 and 10.10.10.0) and two for lo0).
I have two questions:
1- does UDP packet add entry to the table? UDP is connectionless, maybe
the
route is saved elsewhere or differently.
2- The target machine is running eCos with Redboot. Both have an IP
Address
but only are using the same MAC. The route should be to Redboot (that will
pass it to eCos)? That is what I see with Ethereal, Ethernet destination
is
Redboot and IP destination is eCos.
For LwIp, I will definitely take a look at it, but I will wait that the
patches to the latest version will be accepted.
Thanks,
Michael
-----Original Message-----
From: Birahim Larou Fall [mailto:BLFall@scmmicro.fr]
Sent: March 27, 2006 3:17 AM
To: Michael Grimard
Cc: ecos-discuss@sourceware.org
Subject: Re: [ECOS] ARP static entry
The code posted by Sebastien just add a route in ARP table but does not
disable/bypass the ARP protocole. What does the function ioct returns?
use show_network_tables(); to print all routes:
typedef int pfunc( const char *fmt, ... )
CYGBLD_ATTRIB_PRINTF_FORMAT(1,2);
externC void show_network_tables(pfunc *pfct);//
packages/net/bsd_tcpip/current/src/ecos/support.c
show_network_tables(diag_printf);// show all routes.
Why you don't use use LWIP stack? you can easily remove the ARP protocole.
Give more informations about your project.
PS: je parle franÃais mais l'anglais permet d'en faire profiter un max de
softer.
Fall Birahim
Elsys Design for SCM Microsystems
"Michael Grimard" <michaelg@maxt.com>
Sent by: ecos-discuss-owner@ecos.sourceware.org
25/03/2006 04:28
To
<ecos-discuss@sourceware.org>
cc
Subject
[ECOS] ARP static entry
Hi,
I need to enter some entries in the ARP table to bypass the ARP protocol
with the FreeBSD stack.
I started by using the code that came with this previous post:
http://sourceware.org/ml/ecos-discuss/2005-09/msg00023.html but I canât
make
it work.
Say that I want to link the IP Address 10.10.10.90 to Ethernet Address
00:07:E9:E3:07:A7, what will the parameters be to the call of AddMAC
function?
Any help/suggestion will be greatly appreciated. Iâm new to eCos and
networking stuff, so Iâm a little lost hereâ
Thanks,
Michael
P.S.: Je parle franÃais, alors si SÃbastien Couret est encore sur la
liste,
tu peux me faire un reply en franÃais.
int AddMAC(const char* dest,const char* gateway,const int index)
{
struct sockaddr_dl gway; // Adresse passerelle
struct sockaddr_in dst; // RÃseau/hote cible
char ds[IPSTRING];
struct ecos_rtentry *rt=NULL; // EntrÃe dans la table de routage
int s=0; // Descripteur de socket
u_char cp[MACSTRING]; // Adresse MAC sous forme chaine
memset(&gway,0,sizeof(struct sockaddr_dl));
gway.sdl_family=AF_LINK; // AF_UNSPEC ?
gway.sdl_len=sizeof(struct sockaddr_dl);
gway.sdl_index=index;
gway.sdl_type=IFT_ETHER;
gway.sdl_alen=ETHER_ADDR_LEN;
memcpy(gway.sdl_data,gateway,ETHER_ADDR_LEN);
memset(&dst,0,sizeof(struct sockaddr_in));
dst.sin_family=AF_INET;
dst.sin_port=0;
dst.sin_len=sizeof(struct sockaddr_in);
dst.sin_addr.s_addr=inet_addr(dest);
rt=(struct ecos_rtentry*)malloc(sizeof(struct ecos_rtentry));
if (!rt)
{
diag_printf("Erreur d'allocation d'une route :'%s'",strerror(errno));
return(-1);
}
memset(rt,0,sizeof(struct ecos_rtentry));
rt->rt_flags|=RTF_LLINFO;
rt->rt_flags|=RTF_HOST; // Host entry
memcpy(&(rt->rt_gateway), &gway, sizeof(struct sockaddr));
memcpy(&(rt->rt_dst), &dst, sizeof(struct sockaddr_in));
rt->rt_flags|=RTF_UP; // Route utilisable
// rt->rt_flags|=RTF_WAS_CLONED;
//rt->rt_use=0;
rt->rt_dev=NULL;
rt->rt_metric=1; // Reseau local
strncpy(ds,inet_ntoa(dst.sin_addr),IPSTRING);
ether_print((u_char*)gateway,(char*)cp,MACSTRING);
diag_printf("Ajout d'une adresse MAC pour '%s' :'%s' sur interface
eth%d",ds,cp,index-1);
s=socket(AF_INET,SOCK_DGRAM,0);
if (s<0)
{
diag_printf("Socket error :'%s'",strerror(errno));
free(rt);
return(-1);
}
if (ioctl(s,SIOCADDRT,rt)<0)
{
diag_printf("Ioctl error :'%s'",strerror(errno));
switch (errno)
{
case EINVAL:diag_printf("Invalid Command or agument");
break;
case ENOTTY:diag_printf("Not a device");
break;
case EBADF:diag_printf("Bad File descriptor");
break;
case EEXIST:diag_printf("Already existing");
break;
default:diag_printf("Unknown error %d:'%s'",errno,strerror(errno));
}
free(rt);
close(s);
return (-1);
}
diag_printf("ARP entry added");
free(rt);
close(s);
return(0);
}
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