/* * leaseshelper.c: Helper program to create custom leases file * * Copyright (C) 2014 Red Hat, Inc. * Copyright (C) 2014 Nehal J Wani * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library. If not, see * . * * For IPv6 support, use dnsmasq >= 2.67 */ #include #include "virthread.h" #include "virfile.h" #include "virpidfile.h" #include "virstring.h" #include "virerror.h" #include "viralloc.h" #include "virjson.h" #include "virlease.h" #include "virenum.h" #include "configmake.h" #include "virgettext.h" #define VIR_FROM_THIS VIR_FROM_NETWORK static const char *program_name; /* Display version information. */ static void helperVersion(const char *argv0) { printf("%s (%s) %s\n", argv0, PACKAGE_NAME, PACKAGE_VERSION); } ATTRIBUTE_NORETURN static void usage(int status) { if (status) { fprintf(stderr, _("%s: try --help for more details\n"), program_name); } else { printf(_("Usage: %s add|old|del|init mac|clientid ip [hostname]\n" "Designed for use with 'dnsmasq --dhcp-script'\n" "Refer to man page of dnsmasq for more details'\n"), program_name); } exit(status); } /* Flags denoting actions for a lease */ enum virLeaseActionFlags { VIR_LEASE_ACTION_ADD, /* Create new lease */ VIR_LEASE_ACTION_OLD, /* Lease already exists, renew it */ VIR_LEASE_ACTION_DEL, /* Delete the lease */ VIR_LEASE_ACTION_INIT, /* Tell dnsmasq of existing leases on restart */ VIR_LEASE_ACTION_LAST }; VIR_ENUM_DECL(virLeaseAction); VIR_ENUM_IMPL(virLeaseAction, VIR_LEASE_ACTION_LAST, "add", "old", "del", "init", ); int main(int argc, char **argv) { char *pid_file = NULL; char *custom_lease_file = NULL; const char *ip = NULL; const char *mac = NULL; const char *leases_str = NULL; const char *iaid = virGetEnvAllowSUID("DNSMASQ_IAID"); const char *clientid = virGetEnvAllowSUID("DNSMASQ_CLIENT_ID"); const char *interface = virGetEnvAllowSUID("DNSMASQ_INTERFACE"); const char *hostname = virGetEnvAllowSUID("DNSMASQ_SUPPLIED_HOSTNAME"); char *server_duid = NULL; int action = -1; int pid_file_fd = -1; int rv = EXIT_FAILURE; bool delete = false; virJSONValuePtr lease_new = NULL; virJSONValuePtr leases_array_new = NULL; virSetErrorFunc(NULL, NULL); virSetErrorLogPriorityFunc(NULL); program_name = argv[0]; if (virGettextInitialize() < 0 || virThreadInitialize() < 0 || virErrorInitialize() < 0) { fprintf(stderr, _("%s: initialization failed\n"), program_name); exit(EXIT_FAILURE); } /* Doesn't hurt to check */ if (argc > 1) { if (STREQ(argv[1], "--help")) usage(EXIT_SUCCESS); if (STREQ(argv[1], "--version")) { helperVersion(argv[0]); exit(EXIT_SUCCESS); } } if (argc != 4 && argc != 5 && argc != 2) { /* Refer man page of dnsmasq --dhcp-script for more details */ usage(EXIT_FAILURE); } /* Make sure dnsmasq knows the interface. The interface name is not known * via env variable set by dnsmasq when dnsmasq (re)starts and throws 'del' * events for expired leases. So, libvirtd sets another env var for this * purpose */ if (!interface && !(interface = virGetEnvAllowSUID("VIR_BRIDGE_NAME"))) goto cleanup; ip = argv[3]; mac = argv[2]; if ((action = virLeaseActionTypeFromString(argv[1])) < 0) { fprintf(stderr, _("Unsupported action: %s\n"), argv[1]); exit(EXIT_FAILURE); } /* In case hostname is known, it is the 5th argument */ if (argc == 5) hostname = argv[4]; /* Check if it is an IPv6 lease */ if (iaid) { mac = virGetEnvAllowSUID("DNSMASQ_MAC"); clientid = argv[2]; } if (VIR_STRDUP(server_duid, virGetEnvAllowSUID("DNSMASQ_SERVER_DUID")) < 0) goto cleanup; if (virAsprintf(&custom_lease_file, LOCALSTATEDIR "/lib/libvirt/dnsmasq/%s.status", interface) < 0) goto cleanup; if (VIR_STRDUP(pid_file, LOCALSTATEDIR "/run/leaseshelper.pid") < 0) goto cleanup; /* Try to claim the pidfile, exiting if we can't */ if ((pid_file_fd = virPidFileAcquirePath(pid_file, true, getpid())) < 0) goto cleanup; /* Since interfaces can be hot plugged, we need to make sure that the * corresponding custom lease file exists. If not, 'touch' it */ if (virFileTouch(custom_lease_file, 0644) < 0) goto cleanup; switch ((enum virLeaseActionFlags) action) { case VIR_LEASE_ACTION_ADD: case VIR_LEASE_ACTION_OLD: /* Create new lease */ if (virLeaseNew(&lease_new, mac, clientid, ip, hostname, iaid, server_duid) < 0) goto cleanup; /* Custom ipv6 leases *will not* be created if the env-var DNSMASQ_MAC * is not set. In the special case, when the $(interface).status file * is not already present and dnsmasq is (re)started, the corresponding * ipv6 custom lease will be created only when the guest sends the * 'old' action for its existing ipv6 interfaces. * * According to rfc3315, the combination of DUID and IAID can be used * to uniquely identify each ipv6 guest interface. So, in future, if * we introduce virNetworkGetDHCPLeaseBy(IAID|DUID|IAID+DUID) for ipv6 * interfaces, then, the following if condition won't be required, as * the new lease will be created irrespective of whether the MACID is * known or not. */ if (!lease_new) break; ATTRIBUTE_FALLTHROUGH; case VIR_LEASE_ACTION_DEL: /* Delete the corresponding lease, if it already exists */ delete = true; break; case VIR_LEASE_ACTION_INIT: case VIR_LEASE_ACTION_LAST: break; } if (!(leases_array_new = virJSONValueNewArray())) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("failed to create json")); goto cleanup; } if (virLeaseReadCustomLeaseFile(leases_array_new, custom_lease_file, delete ? ip : NULL, &server_duid) < 0) goto cleanup; switch ((enum virLeaseActionFlags) action) { case VIR_LEASE_ACTION_INIT: if (virLeasePrintLeases(leases_array_new, server_duid) < 0) goto cleanup; break; case VIR_LEASE_ACTION_OLD: case VIR_LEASE_ACTION_ADD: if (lease_new && virJSONValueArrayAppend(leases_array_new, lease_new) < 0) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("failed to create json")); goto cleanup; } lease_new = NULL; ATTRIBUTE_FALLTHROUGH; case VIR_LEASE_ACTION_DEL: if (!(leases_str = virJSONValueToString(leases_array_new, true))) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("empty json array")); goto cleanup; } /* Write to file */ if (virFileRewriteStr(custom_lease_file, 0644, leases_str) < 0) goto cleanup; break; case VIR_LEASE_ACTION_LAST: break; } rv = EXIT_SUCCESS; cleanup: if (pid_file_fd != -1) virPidFileReleasePath(pid_file, pid_file_fd); VIR_FREE(pid_file); VIR_FREE(server_duid); VIR_FREE(custom_lease_file); virJSONValueFree(lease_new); virJSONValueFree(leases_array_new); return rv; }