* [ECOS] How to change MTU?
@ 2006-05-15 6:17 蔡述宪
2006-05-17 8:25 ` Birahim Larou Fall
0 siblings, 1 reply; 2+ messages in thread
From: 蔡述宪 @ 2006-05-15 6:17 UTC (permalink / raw)
To: ecos-discuss
Hello, everyone!
I am now implementing a router using eCos. I want to change the MTU
of one of my two network interfaces. I tried to do that using the
socket to kernel routing table, here is my code:
//for route add and delete
u_int32_t g,m,d;
int routes;
struct {
struct rt_msghdr hdr;
struct sockaddr_in dst;
struct sockaddr_in gway;
struct sockaddr_in mask;
} rtmsg;
if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
diag_printf("Error: route socket\n");
}
//change route for MTU of eth1
g = 0x64300100;
m = 0xFFFFFF00;
d = 0x64300100;
g = htonl(g);
m = htonl(m);
d = htonl(d);
memset(&rtmsg, 0, sizeof(rtmsg));
rtmsg.hdr.rtm_type = RTM_CHANGE;
rtmsg.hdr.rtm_flags = RTF_UP | RTF_HOST |RTF_STATIC;
rtmsg.hdr.rtm_version = RTM_VERSION;
rtmsg.hdr.rtm_seq = ++rtm_seq;
rtmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY | RTA_NETMASK;
rtmsg.hdr.rtm_rmx.rmx_locks = 0;
rtmsg.hdr.rtm_rmx.rmx_mtu = 1000;
rtmsg.dst.sin_len = sizeof(rtmsg.dst);
rtmsg.dst.sin_family = AF_INET;
rtmsg.dst.sin_addr.s_addr = d;
rtmsg.gway.sin_len = sizeof(rtmsg.gway);
rtmsg.gway.sin_family = AF_INET;
rtmsg.gway.sin_addr.s_addr = g;
rtmsg.mask.sin_len = sizeof(rtmsg.dst);
rtmsg.mask.sin_family = AF_INET;
rtmsg.mask.sin_addr.s_addr = m;
rtmsg.hdr.rtm_msglen = sizeof(rtmsg);
if (write(routes, &rtmsg, sizeof(rtmsg)) < 0) {
diag_printf("Error:route change failed\n");
}
close(routes);
It seems that the write operation is successful, because I got no
error message. But the MTU of my interface didn't change after that.
Following is the output from show_network_tables():
Routing tables
Destination Gateway Mask Flags Interface
100.48.1.0 100.48.1.0 255.255.255.0 U eth1
100.48.1.2 100.48.1.2 UH eth0
127.0.0.0 127.0.0.1 255.0.0.0 UG lo0
127.0.0.1 127.0.0.1 UH lo0
162.105.75.0 162.105.75.0 255.255.255.0 U eth0
162.105.78.0 100.48.1.2 255.255.255.0 UGS eth1
Interface statistics
eth0 IP: 162.105.75.1, Broadcast: 162.105.75.255, Netmask:
255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU: 1500, Metric: 0
Rx - Packets: 0, Bytes: 0, Tx - Packets: 0, Bytes: 0
eth1 IP: 100.48.1.1, Broadcast: 100.48.1.255, Netmask: 255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU: 1500, Metric: 0
Rx - Packets: 0, Bytes: 0, Tx - Packets: 0, Bytes: 0
lo0 IP: 127.0.0.1, Broadcast: 127.0.0.1, Netmask: 255.0.0.0
UP LOOPBACK RUNNING MULTICAST MTU: 16384, Metric: 0
Rx - Packets: 0, Bytes: 0, Tx - Packets: 0, Bytes: 0
Why the MTU change didn't take effect? The MTU of eth1 is still 1500
but not 1000. Is there something wrong with my code?
Anybody done similar operation before? Thank you very much for your
suggestion!
--
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [ECOS] How to change MTU?
2006-05-15 6:17 [ECOS] How to change MTU? 蔡述宪
@ 2006-05-17 8:25 ` Birahim Larou Fall
0 siblings, 0 replies; 2+ messages in thread
From: Birahim Larou Fall @ 2006-05-17 8:25 UTC (permalink / raw)
To: 蔡述宪; +Cc: ecos-discuss
Why you don't use ioctl command with SIOCSIFMTU(arg2) as command to
change MTU. See " if_ethersubr.c" in freebsd sources.
You have to fill the ifreq struct (for the interface you want to change
the MTU)
Fall Birahim
Digital TV Firmware Engineer
Elsys Design for SCM Microsystems
La Ciotat - France
+33 (0)4 42 83 87 31
Mobile : +33 (0)6 61 40 94 81
bfall@scmmicro.com
蔡述宪 <caishuxian@water.pku.edu.cn>
Sent by: ecos-discuss-owner@ecos.sourceware.org
15/05/2006 08:17
To
ecos-discuss@sources.redhat.com
cc
Subject
[ECOS] How to change MTU?
Hello, everyone!
I am now implementing a router using eCos. I want to change the MTU
of one of my two network interfaces. I tried to do that using the
socket to kernel routing table, here is my code:
//for route add and delete
u_int32_t g,m,d;
int routes;
struct {
struct rt_msghdr hdr;
struct sockaddr_in dst;
struct sockaddr_in gway;
struct sockaddr_in mask;
} rtmsg;
if ((routes = socket(PF_ROUTE, SOCK_RAW, AF_INET)) < 0) {
diag_printf("Error: route socket\n");
}
//change route for MTU of eth1
g = 0x64300100;
m = 0xFFFFFF00;
d = 0x64300100;
g = htonl(g);
m = htonl(m);
d = htonl(d);
memset(&rtmsg, 0, sizeof(rtmsg));
rtmsg.hdr.rtm_type = RTM_CHANGE;
rtmsg.hdr.rtm_flags = RTF_UP | RTF_HOST |RTF_STATIC;
rtmsg.hdr.rtm_version = RTM_VERSION;
rtmsg.hdr.rtm_seq = ++rtm_seq;
rtmsg.hdr.rtm_addrs = RTA_DST | RTA_GATEWAY |
RTA_NETMASK;
rtmsg.hdr.rtm_rmx.rmx_locks = 0;
rtmsg.hdr.rtm_rmx.rmx_mtu = 1000;
rtmsg.dst.sin_len = sizeof(rtmsg.dst);
rtmsg.dst.sin_family = AF_INET;
rtmsg.dst.sin_addr.s_addr = d;
rtmsg.gway.sin_len = sizeof(rtmsg.gway);
rtmsg.gway.sin_family = AF_INET;
rtmsg.gway.sin_addr.s_addr = g;
rtmsg.mask.sin_len = sizeof(rtmsg.dst);
rtmsg.mask.sin_family = AF_INET;
rtmsg.mask.sin_addr.s_addr = m;
rtmsg.hdr.rtm_msglen = sizeof(rtmsg);
if (write(routes, &rtmsg, sizeof(rtmsg)) < 0) {
diag_printf("Error:route change
failed\n");
}
close(routes);
It seems that the write operation is successful, because I got no
error message. But the MTU of my interface didn't change after that.
Following is the output from show_network_tables():
Routing tables
Destination Gateway Mask Flags Interface
100.48.1.0 100.48.1.0 255.255.255.0 U eth1
100.48.1.2 100.48.1.2 UH eth0
127.0.0.0 127.0.0.1 255.0.0.0 UG lo0
127.0.0.1 127.0.0.1 UH lo0
162.105.75.0 162.105.75.0 255.255.255.0 U eth0
162.105.78.0 100.48.1.2 255.255.255.0 UGS eth1
Interface statistics
eth0 IP: 162.105.75.1, Broadcast: 162.105.75.255, Netmask:
255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU: 1500, Metric: 0
Rx - Packets: 0, Bytes: 0, Tx - Packets: 0, Bytes: 0
eth1 IP: 100.48.1.1, Broadcast: 100.48.1.255, Netmask: 255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU: 1500, Metric: 0
Rx - Packets: 0, Bytes: 0, Tx - Packets: 0, Bytes: 0
lo0 IP: 127.0.0.1, Broadcast: 127.0.0.1, Netmask: 255.0.0.0
UP LOOPBACK RUNNING MULTICAST MTU: 16384, Metric: 0
Rx - Packets: 0, Bytes: 0, Tx - Packets: 0, Bytes: 0
Why the MTU change didn't take effect? The MTU of eth1 is still 1500
but not 1000. Is there something wrong with my code?
Anybody done similar operation before? Thank you very much for your
suggestion!
--
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
^ permalink raw reply [flat|nested] 2+ messages in thread
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2006-05-15 6:17 [ECOS] How to change MTU? 蔡述宪
2006-05-17 8:25 ` Birahim Larou Fall
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