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Re: [uml-user] packets get through but no pings (sendmdg: Operation not permitted / MAC incomplete)
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From: Erik de B. - L. <Er...@Lo...> - 2003-08-28 00:03:33
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Hello, I'm replying to my own post because I've succeeded to getting my UML's up and running, and should tell you how (for this thread to be of any use). After compiling my own um kernel from scratch it all went well, everything behaved as I though it should have done in the first place (the first time I've tried). It rather slowed down the whole project a LOT. My reasoning in using a ready made kernel was as following: - I knew people had succeeded in getting networking up and running the way I intended to do so too. - When asking question others could verify with their situation that wouldn't differ too much from mine. - I didn't have time to play with different build options because I was getting late on schedule. My advice, regardless of how good the pre-built kernels are, try to build at least the kernel yourself. You could download a .config of one to get started quickly (usable options) but eventually you'll (probably) want to tweak it anyway. Thanks list, and thanks Jeff! Erik www.BudgetDedicated.com ----- Original Message ----- From: "Erik de Bruijn - LowVoice" <Er...@Lo...> To: <use...@li...> Sent: Monday, August 25, 2003 1:35 AM Subject: [uml-user] packets get through but no pings (sendmdg: Operation not permitted / MAC incomplete) > Hi UML people, > > I've got an (remote) online test box on which I'm trying to get networking > up and running. Since I've been intensly trying for weeks, because I really > NEED it to work (and refuse to give up), I almost know every bit of > documentation about UML networking, and TUN/TAP. > > Before I get nuts, I'd like someone else to have a secound look at what I'm > doing (wrong)! > > Here's my current setup: > - Host > kernel: Linux gen4 2.4.21 #6 Sat Aug 23 23:24:58 CEST 2003 i686 AMD > Athlon(tm) XP 1800+ AuthenticAMD GNU/Linux > distro: gentoo: Gentoo Base System version 1.4.3.8p1 > CONFIG_TUN=y > CONFIG_NETLINK_DEV not set > CONFIG_ETHERTAP not set ##I don't want to use ETHERTAP so NETLINK_DEV > shouln't be necesairy either. > Uplink: eth1 > - User-mode OS: > kernels I've tried it al with: Linux uml1 2.6.0-test3-bk5-1um #1 Sun Aug 17 > 23:12:03 EDT 2003 i686 unknown, both from kernels.usermodelinux.org if I > recall correctly > TAP shows in dmesg: Universal TUN/TAP device driver 1.5 > > My objective: > To be able to ping a UML instance through TUN/TAP (and get response) on a > public IP address from a remote connection, with or without bridging. I'm > trying first without bridging, because when you bridge you I have to set my > uplink to promisc before I get the bridge up again. If I just enter the > commands my ssh connection will be down before I can get the bridge up. I > could do it through a script, but that breaks when the connection is gone as > well. It can be done, but I guess it's risky business when you don't have a > second uplink. I'll have that back next week, along with a minicom-link, so > untill then I'd like to try it without bridging. > > What I'm doing: > I've manually preconfigured the device. I've also skipped this part to let > the uml_net helper do it, but it seems to be exactly what uml_net does. > <skipped> > root# tunctl -u root -t tap0 # creates the device > root# ifconfig tap0 213.123.123.180 netmask 255.255.255.255 up # I've also > tried with mtu 1484 > root# bash -c echo 1 > /proc/sys/net/ipv4/ip_forward > root# route add -host 213.123.123.181 dev tap0 > root# bash -c echo 1 > /proc/sys/net/ipv4/conf/tap0/proxy_arp > root# arp -Ds 213.189.19.181 eth1 pub > </skipped> > The preconfigured device and the uml_net helperconfigured tap could be > pinged by the host at the tap end (ping own tap device @ 213.189.19.180 > works) > If I do the above manually, regardless of whether I start up the UML, when I > ping (or nmap or anything similar) the UML ip 213.123.123.181 I get: > ping: sendmsg: Operation not permitted > ping: sendmsg: Operation not permitted ##ctrl-C > I also get this when the UML runs on the preconfigured device, or when it's > running with the uml_net helper. > > Googling around tells me that I've got to have permissions on the suid-root > /bin/ping, I do, I'm root and it's set setuid anyway. I couldn't find other > leads to what this means and what causes it. It can be related to: arp on > the host shows it has an incomlete HwAddress/MAC (see the command + output > below). > > Below this you'll find A LOT OF EXTRA INFORMATION. Don't feel too much > overloaded, because I only wanted to give all information that's related. > Just read the bits of commands you'd issue to find the problem! > > Thank you (in advance) very much for any help, and (already) for your > attention! > > Best regards, > > Erik > http://www.BudgetDedicated.com/ > > ________________________EXTRA INFO________________________ > ## <-- comments right of double 'sharps', don't confuse with CLI-prompt! > > root# linux \ ## i run UML with this: > eth0=tuntap,[when not-skipping the above: tap0],,213.123.123.180 \ > umid=uml1 con=null con0=fd:0,fd:1 mem=64M > hostfs=/home/uml/uml1/host_fs/ \ > ubd0=/home/uml/uml1/Debian-3.0r0.ext2.5GB \ > ubd1=/home/uml/uml1/swap \ > rootfs=ubd/0 devfs=mount root=ubd/0 > ## both the 2.4.20 and the 2.6.0test3 kernel seem to boot normally, debian > runs smoothly > ##--------boot proces shows:---------- > ##Netdevice 0 : TUN/TAP backend - IP = 213.189.19.180 > ##divert: allocating divert_blk for eth0 > login: root > password: **** > UML# ifconfig eth0 213.123.123.181 up > UML# route > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use > Iface ## routing table seems to be empty > UML# route add -host 213.189.19.181 eth0 > UML# route add default gw 213.189.19.180 > # route -n > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use > Iface > 213.189.19.181 0.0.0.0 255.255.255.255 UH 0 0 0 eth0 > 213.189.19.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 > 0.0.0.0 213.189.19.180 0.0.0.0 UG 0 0 0 eth0 > UML# ifconfig |grep HWaddr > eth0 Link encap:Ethernet HWaddr FE:FD:D5:BD:13:B5 > > HOST# route > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref Use > Iface > 213.123.123.181 * 255.255.255.255 UH 0 0 0 > tap0 > 213.123.123.0 * 255.255.255.0 U 0 0 0 > eth1 > 192.168.1.0 * 255.255.255.0 U 0 0 0 eth0 > loopback localhost 255.0.0.0 UG 0 0 0 lo > default 213.123.123.3 0.0.0.0 UG 0 0 0 > eth1 > > HOST# arp > Address HWtype HWaddress Flags Mask > Iface > 213.189.19.183 (incomplete) > tap-test > 213.189.19.181 (incomplete) > tap0 ## incomplete > 213.189.19.181 ether 00:FF:87:44:62:75 CM > eth1 ## i don't know this HW addres... can this be a problem? > 213.189.19.3 ether 00:00:5E:00:01:21 C > eth1 > 213.189.19.2 ether 00:02:85:0A:C4:80 C > eth1 > 213.189.19.1 ether 00:02:85:0B:AF:40 C > eth1 > 213.189.19.183 * * MP > eth1 > 213.189.19.181 * * MP > eth1 > > HOST# arping 213.189.19.181 -I eth1 > ARPING 213.189.19.181 from 213.189.19.160 eth1 > Unicast reply from 213.189.19.181 [00:00:5E:00:01:21] 0.933ms ##this is the > eth1 MAC address, but I guess the problem's something else. > ##etc. > > HOST# netstat -i #some extra info?! > Kernel Interface table > Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR > Flg > eth0 1500 0 0 0 0 0 0 0 0 > 0 BMPU > eth1 1500 0 4165888 0 0 0 183913 0 0 > 0 BMRU > ext0 1500 0 0 0 0 0 0 0 0 > 0 BMRU > lo 16436 0 643 0 0 0 643 0 0 > 0 LRU > tap0 1500 0 981 0 0 0 942 0 0 > 0 BMRU > > UML# arp -n > Address HWtype HWaddress Flags Mask > Iface > 213.189.19.180 ether 00:FF:3B:CC:1B:6F C > eth0 #this IS the correct MAC for tap0@HOST > > HOST# tcpdump -i tap0 > ## Irregularly outputs packets with: arp who-has 213.189.19.181 tell > 213.189.19.180 > ## I'm doing nothing on host or UML. > > What else to investigate?! > |
