topic Re: how to set/change gateway setting or make it accept connection from different subnet in MQX Software Solutions

how to set/change gateway setting or make it accept connection from different subnet

David_Wu — Wed, 04 Jul 2012 01:41:09 GMT

I noticed the gatewy settings in IP Config in RTCS menu in CW10.2

gateways

network gateway

0.0.0.0/0 192.168.100.1

192.168.1.102/32 192.168.1.102

My configuration is: DHCP enabled - got an IP 192.168.100.185, gateway 192.168.100.1, netmask 255.255.255.0.

I can connect 192.168.100.185 from 192.168.100.4 - same subnet - but I couldn't from 192.168.1.102

Anyone know if the gateway setting is correct in MQX RTCS and if not how to change it? (I know how to set the default gateway - I don't know how to change the extra gateway info above -). Why there is an extra routing entry?

what settings can make it accept a connection from a different subnet - timeout issue, routing issue, socket option issue , what ever to make it work?

thanks in advance,

David

Re: how to set/change gateway setting or make it accept connection from different subnet

David_Wu — Thu, 29 Oct 2020 09:26:19 GMT

updates:It seems there is no route back to the host that makes the connection. I got the error is:TCP: TCP_Send_IP_packet: errno 1510 on IP_send.If I change the netmask to accommodate two subnets then the TCP connection works. Further investigation indicates that it looks like MQX did not support ICMP redirect messages from gateway.

Re: how to set/change gateway setting or make it accept connection from different subnet

David_Wu — Tue, 29 Jan 2013 17:35:07 GMT

By changing the netmask is only a work around and not a fix - I'd like to know if the MQX team will find a solution?

Re: how to set/change gateway setting or make it accept connection from different subnet

butok — Wed, 30 Jan 2013 09:41:57 GMT

The communication between two nodes from different networks is done via a gateway.

Nodes can communicates directly (without gateway) only if they belong to the same network. It is defined by the netmask.

Re: how to set/change gateway setting or make it accept connection from different subnet

David_Wu — Fri, 21 Jun 2013 20:10:27 GMT

But when it comes to ICMP redirct, things changed. If the Default gateway tells the K60 to contact the end device directly then regardless the netmask, K60 should setup a ROUTING rule for it to reach.

Here is what I did as a work around (add a indirect routing rule):

in icmp.c for case ICMPTYPE_REDIRECT in ICMP_service() I add the detection for redirect for a host and call RTCSCMD_internal(parms, IPIF_gate_add_redirect_other) instead - IPIF_gate_add_redirect_other is the function I added in ipif_add.c (see below ) - note that I add two more parameters in IP_route_add_indirect(). Also in IP_route_test() I check for RTF_REDIRECT_HOST flag and return the correct info if match.

I might miss some source code - but you should get the idea.

-----------------

icmp.c

------------------

@@ -99,7 +99,7 @@

_ip_address source, dest;

uint_32 error;

uint_16 chksum;

- uchar type;

+ uchar type, code;

ICMP_cfg_ptr = RTCS_getcfg(ICMP);

@@ -109,6 +109,7 @@

source = IP_source(pcb);

dest = IP_dest(pcb);

type = ntohc(packet->TYPE);

+ code = ntohc(packet->CODE);

** Make sure that

@@ -170,6 +171,14 @@

parms.network = origdest;

parms.netmask = 0xFFFFFFFFL;

parms.locmask = 0;

+#define ICMP_REDIRECT_FIX 1

+#if ICMP_REDIRECT_FIX //WMQ

+ parms.ihandle = pcb->IFSRC;

+ if(code == ICMPCODE_RD_HOST){

+ parms.address = dest;

+ RTCSCMD_internal(parms, IPIF_gate_add_redirect_other);

+ } else

+#endif

RTCSCMD_internal(parms, IPIF_gate_add_redirect);

} else {

IF_ICMP_STATS_ENABLED(ICMP_cfg_ptr->STATS.COMMON.ST_RX_DISCARDED++);

---------------------------------------

rtcs/source/tcpip/ipif_add.c

-----------------------------------------

+/* for ICMP redirect when gateway is the destination */

+void IPIF_gate_add_redirect_other

+ (

+ IPIF_PARM_PTR parms

+ )

+{ /* Body */

+#if RTCSCFG_ENABLE_IP4

+ _ip_address netmask = parms->netmask;

+ uint_32 error;

+ /*

+ ** Make sure the netmask is valid. We use the fact that

+ ** (x & x+1) == 0 <=> x = 2^n-1.

+ */

+ if (~netmask & (~netmask + 1)) {

+ RTCSCMD_complete(parms, RTCSERR_IP_BIND_MASK);

+ return;

+ } /* Endif */

+ /* Start CR 1133 */

+ //error = IP_route_add_direct(parms->address, parms->netmask, (IP_IF_PTR)parms->ihandle, (IP_IF_PTR)parms->ihandle); /* this one causes memory leak*/

+ error = IP_route_add_indirect(parms->network, netmask, parms->network, RTF_REDIRECT | RTF_REDIRECT_HOST, parms->locmask, (IP_IF_PTR)parms->ihandle,parms->address);

+ RTCSCMD_complete(parms, error);

+#else

+ RTCSCMD_complete(parms, RTCSERR_IP_IS_DISABLED);

+#endif /* RTCSCFG_ENABLE_IP4 */

+} /* Endbody */

--------------------------------------------

rtcs/source/tcpip/iproute.c

--------------------------------------------

uint_32 IP_route_add_indirect

(

_ip_address address, /* Gateway address */

@@ -373,7 +373,9 @@

_ip_address netmask, /* Network mask */

_ip_address network, /* Network address */

uint_32 flag, /* [IN] RTF_* */

- uint_16 metric /* [IN] the route metric [0,65535] */

+ uint_16 metric, /* [IN] the route metric [0,65535] */

+ IP_IF_PTR destif, /* WMQ:Interface for outgoing packets */

+ _ip_address source /* WMQ: source address to send */

)

{ /* Body */

IP_CFG_STRUCT_PTR IP_cfg_ptr = RTCS_getcfg(IP);

@@ -390,6 +392,8 @@

route->FLAGS = flag | RTF_UP;

route->IS_DIRECT = NULL;

route->METRIC = metric;

+ route->DESTIF = destif; //WMQ

+ route->ADDRESS = source; //WMQ

-------------------------------------------

static boolean IP_route_test

(

pointer node_data,

pointer data

)

{ /* Body */

.....

if (indirect && testdata->check_gateway) {

do {

if (indirect->FLAGS & RTF_UP) {

testdata->hopdest = indirect->GATEWAY;

#if 1

if(indirect->FLAGS & RTF_REDIRECT_HOST){

testdata->sendit = TRUE;

testdata->ifdest = indirect->DESTIF;

testdata->retval = RTCS_OK;

if (!testdata->hopsrcislocal) {

testdata->hopsrc = indirect->ADDRESS;

} /* Endif */

}

#endif

/* Notify calling function that a gateway was found */

testdata->check_gateway = FALSE;

return TRUE;

} /* Endif */

indirect = indirect->NEXT;

} while(indirect != route->INDIRECT);

---------------------------------------------

rtcs/source/include/ip_prv.h

---------------------------------------------

#define RTF_REDIRECT_HOST

0x0008

/* created for a ICMP redirect for a host*/

Re: how to set/change gateway setting or make it accept connection from different subnet

butok — Mon, 01 Jul 2013 08:31:10 GMT

Hi David,

We have never tested handling of the ICMPv4 Redirect messages. So I have added the task to our backlog.

BTW: What have you used to produce the ICMPv4 redirect messages? Do you use a special/customizable switch?

Thanks,

Andrey

Re: how to set/change gateway setting or make it accept connection from different subnet

GottiLuca — Tue, 02 Jul 2013 07:21:02 GMT

Dear David,

It's quite normal that you could not connect to another subnet .

In such cases you have two options :

- You can try to connect the two nodes directly ( i.e. : without using gateway ) increasing the netmask from 255.255.255.0 to a larger one ( i.e. : 255.255.0.0 ). In such a case, you have to set this same netmask on the other node ( 192.168.1.102 ).

- if you don't wanna modify the netmask, you muast have a gateway ( 192.168.100.1 ) that routes the messages bidirectonally from the two subnets ( 192.168.100.x and 192.168.1.x ) . This is usually a functionality that requires a routers or , more appropriate ,a firewall .

Re: how to set/change gateway setting or make it accept connection from different subnet

David_Wu — Tue, 02 Jul 2013 19:19:22 GMT

The easiest way to instrument this is to enable a Linux PC with two Ethernet(s) to act as your network gateway

On LINUX PC (acting as Router/Gateway)

Ethernet 1 (Ethernet link to real network gateway 192.168.0.1 <=> 192.168.0.100 )

ifconfig eth0 192.168.0.1 netwmask 255.255.255.0

route add default gw 192.168.0.100

Ethernet 2 ( Ethernet support two seperare class C Lan spaces 192.168.1.1/24 and 192.168.100.1/24 ) connected to a HUB or a SWITCH

ifconfig eth1:0 192.168.1.1 netmask 255.255.255.0

route add 192.168.1.0/24 eth1

ifconfig eth1:1 192.168.100.1 netmask 255.255.255.0

route add 192.168.100.0/24 eth1

Ensure you enable the LINUX mahine as a router. You can do this typically through the /proc file system.

Enable IP Forwarding like such:

echo 1 > /proc/sys/net/ipv4/ip_forward

See the link below for information on enable the sending of redirects based on interface and network load.

http://tldp.org/HOWTO/Adv-Routing-HOWTO/lartc.kernel.obscure.html