Re: [libvirt PATCH 5/9] conf: parse/format passt-related XML additions

This implements XML config to represent a subset of the features supported by 'passt' (https://passt.top), which is an alternative backend for emulated network devices that requires no elevated privileges (similar to slirp, but "better"). Along with setting the backend to use passt (via <backend type='passt'/> when the interface type='user'), we also support passt's --log-file and --interface options (via the <backend> subelement logFile and upstream attributes) and its --tcp-ports and --udp-ports options (which selectively forward incoming connections to the host on to the guest) via the new <portForward> subelement of <interface>. Here is an example of the config for a network interface that uses passt to connect: <interface type='user'> <mac address='52:54:00:a8:33:fc'/> <ip address='192.168.221.122' family='ipv4'/> <model type='virtio'/> <backend type='passt' logFile='/tmp/xyzzy.log' upstream='eth0'/> <portForward address='10.0.0.1' proto='tcp' dev='eth0'> <range start='2022' to='22'/> <range start='5000' end='5099' to='1000'/> <range start='5010' end='5029' exclude='yes'/> </portForward> <portForward proto='udp'> <range start='10101'/> </portForward> </interface> In this case: * the guest will be offered address 192.168.221.122 for its interface via DHCP * the passt process will write all log messages to /tmp/xyzzy.log * routes to the outside for the guest will be derived from the addresses and routes associated with the host interface "eth0". * incoming tcp port 2022 to the host will be forwarded to port 22 on the guest. * incoming tcp ports 5000-5099 (with the exception of ports 5010-5029) to the host will be forwarded to port 1000-1099 on the guest. * incoming udp packets on port 10101 will be forwarded (unchanged) to the guest. Signed-off-by: Laine Stump <laine(a)redhat.com&gt; --- docs/formatdomain.rst | 95 +++++++- src/conf/domain_conf.c | 242 +++++++++++++++++++- src/conf/domain_conf.h | 40 ++++ src/conf/domain_validate.c | 32 ++- src/conf/virconftypes.h | 4 + src/libvirt_private.syms | 1 + tests/qemuxml2xmloutdata/net-user-passt.xml | 1 + tests/qemuxml2xmltest.c | 1 + 8 files changed, 401 insertions(+), 15 deletions(-) create mode 120000 tests/qemuxml2xmloutdata/net-user-passt.xml

+static int +virDomainNetPortForwardRangesParseXML(virDomainNetPortForward *def, + xmlXPathContextPtr ctxt) +{ + int nRanges; + g_autofree xmlNodePtr *ranges = NULL; + size_t i; + + if ((nRanges = virXPathNodeSet("./range", + ctxt, &ranges)) <= 0) {

+ return nRanges; + } + + def->ranges = g_new0(virDomainNetPortForwardRange *, nRanges); + + for (i = 0; i < nRanges; i++) { + g_autofree virDomainNetPortForwardRange *range = NULL; +

@@ -23274,17 +23435,91 @@ static void virDomainNetBackendFormat(virBuffer *buf, virDomainNetBackend *backend) { - - if (!(backend->tap || backend->vhost)) + if (!(backend->type || backend->tap || backend->vhost + || backend->logFile || backend->upstream)) {

return; + }

+ if (net->type != VIR_DOMAIN_NET_TYPE_USER) { + if (net->backend.type == VIR_DOMAIN_NET_BACKEND_PASST) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("\"<backend type='passt'/>\" can only be used with \"<interface type='user'>\""));

+ return -1; + } + } + switch (net->type) { case VIR_DOMAIN_NET_TYPE_VHOSTUSER: if (!virDomainNetIsVirtioModel(net)) {