- 13 4月, 2010 1 次提交
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由 Stefan Berger 提交于
Changes from v1 to v2: - changed function name prefixes to 'iface' from previous 'Iface' - Further to make make syntax-check pass: - indentation fix in interface.h - added entry to POTFILES.in I am consolidating network interface related functions used in nwfilter and macvtap code in utils/interface.c. All function names are prefixed with 'Iface'. The following functions are now available through interface.h: int ifaceCtrl(const char *name, bool up); int ifaceUp(const char *name); int ifaceDown(const char *name); int ifaceCheck(bool reportError, const char *ifname, const unsigned char *macaddr, int ifindex); int ifaceGetIndex(bool reportError, const char *ifname, int *ifindex); I added 'int ifindex' as parameter to ifaceCheck to the original function and modified the code accordingly.
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- 10 4月, 2010 1 次提交
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由 Stefan Berger 提交于
I mistakenly took the op field in the DHCP message as the DHCP_OFFER type. Rather than basing the decision to read the VM's IP address on that field, process the appended DHCP options where option 53 indicates the actual type of the packet. I am also reading the broadcast address of the VM, but don't use it so far.
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- 08 4月, 2010 1 次提交
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由 Stefan Berger 提交于
This patch implements support for learning a VM's IP address. It uses the pcap library to listen on the VM's backend network interface (tap) or the physical ethernet device (macvtap) and tries to capture packets with source or destination MAC address of the VM and learn from DHCP Offers, ARP traffic, or first-sent IPv4 packet what the IP address of the VM's interface is. This then allows to instantiate the network traffic filtering rules without the user having to provide the IP parameter somewhere in the filter description or in the interface description as a parameter. This only supports to detect the parameter IP, which is for the assumed single IPv4 address of a VM. There is not support for interfaces that may have multiple IP addresses (IP aliasing) or IPv6 that may then require more than one valid IP address to be detected. A VM can have multiple independent interfaces that each uses a different IP address and in that case it will be attempted to detect each one of the address independently. So, when for example an interface description in the domain XML has looked like this up to now: <interface type='bridge'> <source bridge='mybridge'/> <model type='virtio'/> <filterref filter='clean-traffic'> <parameter name='IP' value='10.2.3.4'/> </filterref> </interface> you may omit the IP parameter: <interface type='bridge'> <source bridge='mybridge'/> <model type='virtio'/> <filterref filter='clean-traffic'/> </interface> Internally I am walking the 'tree' of a VM's referenced network filters and determine with the given variables which variables are missing. Now, the above IP parameter may be missing and this causes a libvirt-internal thread to be started that uses the pcap library's API to listen to the backend interface (in case of macvtap to the physical interface) in an attempt to determine the missing IP parameter. If the backend interface disappears the thread terminates assuming the VM was brought down. In case of a macvtap device a timeout is being used to wait for packets from the given VM (filtering by VM's interface MAC address). If the VM's macvtap device disappeared the thread also terminates. In all other cases it tries to determine the IP address of the VM and will then apply the rules late on the given interface, which would have happened immediately if the IP parameter had been explicitly given. In case an error happens while the firewall rules are applied, the VM's backend interface is 'down'ed preventing it to communicate. Reasons for failure for applying the network firewall rules may that an ebtables/iptables command failes or OOM errors. Essentially the same failure reasons may occur as when the firewall rules are applied immediately on VM start, except that due to the late application of the filtering rules the VM now is already running and cannot be hindered anymore from starting. Bringing down the whole VM would probably be considered too drastic. While a VM's IP address is attempted to be determined only limited updates to network filters are allowed. In particular it is prevented that filters are modified in such a way that they would introduce new variables. A caveat: The algorithm does not know which one is the appropriate IP address of a VM. If the VM spoofs an IP address in its first ARP traffic or IPv4 packets its filtering rules will be instantiated for this IP address, thus 'locking' it to the found IP address. So, it's still 'safer' to explicitly provide the IP address of a VM's interface in the filter description if it is known beforehand. * configure.ac: detect libpcap * libvirt.spec.in: require libpcap[-devel] if qemu is built * src/internal.h: add the new ATTRIBUTE_PACKED define * src/Makefile.am src/libvirt_private.syms: add the new modules and symbols * src/nwfilter/nwfilter_learnipaddr.[ch]: new module being added * src/nwfilter/nwfilter_driver.c src/conf/nwfilter_conf.[ch] src/nwfilter/nwfilter_ebiptables_driver.[ch] src/nwfilter/nwfilter_gentech_driver.[ch]: plu the new functionality in * tests/nwfilterxml2xmltest: extend testing
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