On Jan 14, 2014, at 2:09 PM, Nehal J Wani <nehaljw.kkd1@gmail.com> wrote:

Introduce helper program to catch events from dnsmasq and maintain a custom lease file per network. It supports DHCPv4 and DHCPv6. The file is saved as "<interface-name>.status".

The format of each lease is: <expiry-time (epoch time)> <mac> <iaid> <ip-address> <hostname> <clientid>

I feel like I'm bikesheding but is it the best idea to have a custom file format? I know our string handling code makes this really easy to do but it just has a slight code smell to make our own format. We link to stuff like yajl and libxml for JSON/XML support and its really simple to do so we could easily write out a JSON/XML file and read it in. Definitely don't rework the patch based on my comments because we'll 99.9% go with this way, I'm just asking a question I felt should be asked.

Example of custom leases file content: 1385245780 52:54:00:2f:ba:76 * 192.168.150.153 * * 1385245781 52:54:00:2f:ba:76 3127926 2001:db8:ca2:2:1::6c * 00:04:76:00:cf:ae:b3:0b:fc:cd:0e:22:2e:97:76:65:74:ec 1385245964 52:54:00:44:7c:d7 * 192.168.150.219 iiit-ad885e4aa1 01:52:54:00:44:7c:d7 1385245964 52:54:00:44:7c:d7 * 192.168.150.219 * 01:52:54:00:44:7c:d7 1385246016 52:54:00:5d:99:92 * 192.168.150.212 iiit-ad885e4aa1 01:52:54:00:5d:99:92 1385246041 52:54:00:3b:16:e0 * 192.168.150.207 * * 1385246081 52:54:00:db:dd:98 * 192.168.150.234 * * 1385246088 52:54:00:db:dd:98 14409112 2001:db8:ca2:2:1::6d * 00:04:76:00:cf:ae:b3:0b:fc:cd:0e:22:2e:97:76:65:74:ec

--- As danpb suggested, I have split the previous patch into helper program & API Refer: https://www.redhat.com/archives/libvir-list/2013-December/msg00694.html Once this get ACKed, I'll send in the patches for the Leases API v6

src/Makefile.am | 20 ++++ src/network/bridge_driver.c | 4 + src/util/leaseshelper.c | 225 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 249 insertions(+) create mode 100644 src/util/leaseshelper.c

diff --git a/src/Makefile.am b/src/Makefile.am index 57e163f..6e5b03c 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -838,6 +838,9 @@ STORAGE_HELPER_DISK_SOURCES = \ UTIL_IO_HELPER_SOURCES = \ util/iohelper.c

+UTIL_LEASES_HELPER_SOURCES = \ + util/leaseshelper.c + # Network filters NWFILTER_DRIVER_SOURCES = \ nwfilter/nwfilter_driver.h nwfilter/nwfilter_driver.c \ @@ -2408,6 +2411,23 @@ libvirt_iohelper_CFLAGS = \ $(NULL) endif WITH_LIBVIRTD

+if WITH_LIBVIRTD +libexec_PROGRAMS += libvirt_leaseshelper +libvirt_leaseshelper_SOURCES = $(UTIL_LEASES_HELPER_SOURCES) +libvirt_leaseshelper_LDFLAGS = \ + $(NULL) +libvirt_leaseshelper_LDADD = \ + libvirt_util.la \ + ../gnulib/lib/libgnu.la +if WITH_DTRACE_PROBES +libvirt_leaseshelper_LDADD += libvirt_probes.lo +endif WITH_DTRACE_PROBES + +libvirt_leaseshelper_CFLAGS = \ + $(PIE_CFLAGS) \ + $(NULL) +endif WITH_LIBVIRTD + if WITH_STORAGE_DISK if WITH_LIBVIRTD libexec_PROGRAMS += libvirt_parthelper diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index 95e4b65..2278dba 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -1063,6 +1063,10 @@ networkBuildDhcpDaemonCommandLine(virNetworkObjPtr network,

cmd = virCommandNew(dnsmasqCapsGetBinaryPath(caps)); virCommandAddArgFormat(cmd, "--conf-file=%s", configfile); + + /* This helper is used to create cutom leases file for libvirt */ + virCommandAddArgFormat(cmd, "--dhcp-script=%s", LIBEXECDIR "/libvirt_leaseshelper"); + *cmdout = cmd; ret = 0; cleanup: diff --git a/src/util/leaseshelper.c b/src/util/leaseshelper.c new file mode 100644 index 0000000..486ebe3 --- /dev/null +++ b/src/util/leaseshelper.c @@ -0,0 +1,225 @@ +/* + * leasehelper.c: Helper program to create custom leases file + * + * Copyright (C) 2013 Red Hat, Inc. + * + * 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 + * <http://www.gnu.org/licenses/>. + * + * Author: Nehal J Wani <nehaljw.kkd1@gmail.com> + * + */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> + +#include "virutil.h" +#include "virthread.h" +#include "virfile.h" +#include "virbuffer.h" +#include "virstring.h" +#include "virerror.h" +#include "viralloc.h" +#include "configmake.h" + +#define VIR_FROM_THIS VIR_FROM_NETWORK + +/** + * VIR_NETWORK_DHCP_LEASE_FIELDS: + * + * Macro providing the maximum number of fields in an entry in + * the leases file + */ +#define VIR_NETWORK_DHCP_LEASE_FIELDS 6 +/** + * VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX: + * + * Macro providing the upper limit on the size of leases file + */ +#define VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX 2097152 + +/* + * Use this when passing possibly-NULL strings to printf-a-likes. + */ +# define EMPTY_STR(s) ((s) ? (s) : "*") + +int +main(int argc, char **argv) { + + /* Doesn't hurt to check */ + if (argc < 4) { + /* Refer man page of dnsmasq --dhcp-script for more details */ + fprintf(stderr, "Usage: $program $action ${mac|clientid} $ip\n"); + return -1; + } + + const char *program_name = argv[0]; + const char *action = argv[1]; + const char *interface = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_INTERFACE")); + const char *expirytime = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_LEASE_EXPIRES")); + const char *mac = argv[2]; + const char *ip = argv[3]; + const char *iaid = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_IAID")); + const char *hostname = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_SUPPLIED_HOSTNAME")); + const char *clientid = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_CLIENT_ID")); + const char *leases_str = NULL; + char *lease_file = NULL; + char *lease_entries = NULL; + char *lease_entry = NULL; + char **lease_fields = NULL; + bool delete = false; + bool add = false; + int rv = -1; + int lease_file_len = 0; + FILE *fp = NULL; + long long expirytime_tmp = 0; + virBuffer buf_new_lease = VIR_BUFFER_INITIALIZER; + virBuffer buf_all_leases = VIR_BUFFER_INITIALIZER; + + if (setlocale(LC_ALL, "") == NULL || + bindtextdomain(PACKAGE, LOCALEDIR) == NULL || + textdomain(PACKAGE) == NULL) { + fprintf(stderr, _("%s: initialization failed\n"), program_name); + exit(EXIT_FAILURE); + } + + if (virThreadInitialize() < 0 || + virErrorInitialize() < 0) { + fprintf(stderr, _("%s: initialization failed\n"), program_name); + exit(EXIT_FAILURE); + } + + if (virAsprintf(&lease_file, "%s/%s.status", LOCALSTATEDIR + "/lib/libvirt/dnsmasq/", interface) < 0) + goto cleanup; + + if (virGetEnvAllowSUID("DNSMASQ_IAID")) { + mac = EMPTY_STR(virGetEnvAllowSUID("DNSMASQ_MAC")); + clientid = argv[2]; + } + + /* Make sure dnsmasq knows the interface, otherwise something is wrong */ + if (STREQ(interface, "*")) + goto cleanup; + + /* Make sure the file exists. If not, 'touch' it */ + if (virFileTouch(lease_file, 0644) < 0) + goto cleanup; + + /* Read entire contents */ + if ((lease_file_len = virFileReadAll(lease_file, + VIR_NETWORK_DHCP_LEASE_FILE_SIZE_MAX, + &lease_entries)) < 0) { + goto cleanup; + } + + if (STREQ(action, "add") || STREQ(action, "old") || STREQ(action, "del")) { + if (mac || STREQ(action, "del")) { + /* Delete the corresponding lease */ + delete = true; + if (STREQ(action, "add") || STREQ(action, "old")) { + fprintf(stderr, "add|old\n"); + add = true; + /* Enter new lease */ + virBufferAsprintf(&buf_new_lease, "%s %s %s %s %s %s\n", + expirytime, mac, iaid, ip, hostname, clientid); + + if (virBufferError(&buf_new_lease)) { + virBufferFreeAndReset(&buf_new_lease); + virReportOOMError(); + goto cleanup; + } + } + } + } + + lease_entry = lease_entries[0] == '\0' ? NULL : lease_entries; + + while (lease_entry) { + int nfields = 0; + + char *eol = strchr(lease_entry, '\n'); + *eol = '\0'; + + /* Split the lease line */ + if (!(lease_fields = virStringSplit(lease_entry, " ", + VIR_NETWORK_DHCP_LEASE_FIELDS))) + goto cleanup; + + nfields = virStringListLength(lease_fields); + + /* Forward lease_entry to the next lease */ + lease_entry = strchr(lease_entry, '\0'); + if (lease_entry - lease_entries + 1 < lease_file_len) + lease_entry++; + else + lease_entry = NULL; + + if (nfields != VIR_NETWORK_DHCP_LEASE_FIELDS) + goto cleanup; + + if (virStrToLong_ll(lease_fields[0], NULL, 10, &expirytime_tmp) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Unable to convert lease expiry time to integer: %s"), + lease_fields[0]); + goto cleanup; + } + + /* Check whether lease has expired or not */ + if (expirytime_tmp < (long long) time(NULL)) + continue; + else if (delete && STREQ(lease_fields[3], ip)) + continue; + else { + virBufferAsprintf(&buf_all_leases, "%s %s %s %s %s %s\n", + lease_fields[0], lease_fields[1], lease_fields[2], + lease_fields[3], lease_fields[4], lease_fields[5]); + + if (virBufferError(&buf_all_leases)) { + virBufferFreeAndReset(&buf_all_leases); + virReportOOMError(); + goto cleanup; + } + } + } + + if (add) { + virBufferAsprintf(&buf_all_leases, "%s", virBufferContentAndReset(&buf_new_lease)); + + if (virBufferError(&buf_all_leases)) { + virBufferFreeAndReset(&buf_all_leases); + virReportOOMError(); + goto cleanup; + } + } + + rv = 0; + + /* Write to file */ + leases_str = virBufferContentAndReset(&buf_all_leases); + if (!leases_str) + leases_str = ""; + + if (virFileWriteStr(lease_file, leases_str, 0) < 0) + rv = -1; + +cleanup: + VIR_FREE(lease_file); + VIR_FREE(lease_entries); + if (lease_fields) + virStringFreeList(lease_fields); + return rv; +} -- 1.8.1.4

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