[libvirt] [PATCH v4 2/5] util: introduce helper to parse message from RTM_GETNEIGH query

From: Chen Hanxiao <chenhanxiao(a)gmail.com&gt; introduce helper to parse RTM_GETNEIGH query message and store it in struct virArpTable. Signed-off-by: Chen Hanxiao <chenhanxiao(a)gmail.com&gt; --- v4: use netlink query instead of parsing /proc/net/arp v3: s/virGetArpTable/virArpTableGet alloc virArpTable in virArpTableGet return ENOSUPP on none-Linux platform move helpers to virarptable.[ch] po/POTFILES.in | 1 + src/Makefile.am | 1 + src/libvirt_private.syms | 5 ++ src/util/virarptable.c | 182 +++++++++++++++++++++++++++++++++++++++++++++++ src/util/virarptable.h | 47 ++++++++++++ 5 files changed, 236 insertions(+) create mode 100644 src/util/virarptable.c create mode 100644 src/util/virarptable.h diff --git a/po/POTFILES.in b/po/POTFILES.in index cbf2accba..0f2ba7490 100644 --- a/po/POTFILES.in +++ b/po/POTFILES.in @@ -193,6 +193,7 @@ src/uml/uml_conf.c src/uml/uml_driver.c src/util/iohelper.c src/util/viralloc.c +src/util/virarptable.c src/util/viraudit.c src/util/virauth.c src/util/virauthconfig.c diff --git a/src/Makefile.am b/src/Makefile.am index 79adc9ba5..dd79b58e0 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -98,6 +98,7 @@ augeastest_DATA = UTIL_SOURCES = \ util/viralloc.c util/viralloc.h \ util/virarch.h util/virarch.c \ + util/virarptable.h util/virarptable.c \ util/viratomic.h util/viratomic.c \ util/viraudit.c util/viraudit.h \ util/virauth.c util/virauth.h \ diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index d90eb3dde..1167220f2 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1346,6 +1346,11 @@ virArchGetWordSize; virArchToString; +# util/virarptable.h +virArpTableFree; +virArpTableGet; + + # util/viraudit.h virAuditClose; virAuditEncode; diff --git a/src/util/virarptable.c b/src/util/virarptable.c new file mode 100644 index 000000000..cbf085403 --- /dev/null +++ b/src/util/virarptable.c @@ -0,0 +1,182 @@ +/* + * virarptable.c Linux ARP table handling + * + * Copyright (C) 2018 Chen Hanxiao + * + * 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/>;. + * + * Authors: + * Chen Hanxiao <chenhanxiao(a)gmail.com&gt; + */ + +#include <config.h> + +#include <stdlib.h> +#include <stdio.h> +#include <arpa/inet.h> + +#include "viralloc.h" +#include "virarptable.h" +#include "virfile.h" +#include "virlog.h" +#include "virnetlink.h" +#include "virsocketaddr.h" +#include "virstring.h" + +#define VIR_FROM_THIS VIR_FROM_NONE + +VIR_LOG_INIT("util.arptable"); + +#ifdef __linux__ + +# define NDA_RTA(r) \ + ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ndmsg)))) + +static int +parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len) +{ + memset(tb, 0, sizeof(struct rtattr *) * (max + 1)); + while (RTA_OK(rta, len)) { + if ((rta->rta_type <= max) && (!tb[rta->rta_type])) + tb[rta->rta_type] = rta; + rta = RTA_NEXT(rta, len); + } + + if (len) + VIR_WARN("malformed netlink message: Deficit %d, rta_len=%d", + len, rta->rta_len); + return 0; +} + +virArpTablePtr virArpTableGet(void) +{ + int num = 0; + int msglen; + void *nlData = NULL; + virArpTablePtr table = NULL; + char *ipstr = NULL; + struct nlmsghdr* nh; + struct rtattr * tb[NDA_MAX+1]; + + msglen = virNetlinkGetNeighbor(&nlData, 0, 0); + if (msglen < 0) + return NULL; + + if (VIR_ALLOC(table) < 0) + return NULL; + + nh = (struct nlmsghdr*)nlData; + + while (NLMSG_OK(nh, msglen)) { + struct ndmsg *r = NLMSG_DATA(nh); + int len = nh->nlmsg_len; + void *addr; + + if ((len -= NLMSG_LENGTH(sizeof(*nh))) < 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("wrong nlmsg len")); + goto cleanup; + } + + if (r->ndm_family && (r->ndm_family != AF_INET)) + goto next_nlmsg; + + /* catch stale and reachalbe arp entry only */ + if (r->ndm_state && + (!(r->ndm_state == NUD_STALE || r->ndm_state == NUD_REACHABLE))) { + nh = NLMSG_NEXT(nh, msglen); + continue; + } + + if (nh->nlmsg_type == NLMSG_DONE) + goto end_of_netlink_messages; + + parse_rtattr(tb, NDA_MAX, NDA_RTA(r), + nh->nlmsg_len - NLMSG_LENGTH(sizeof(*r))); + + if (tb[NDA_DST] == NULL || tb[NDA_LLADDR] == NULL) + goto next_nlmsg; + + if (tb[NDA_DST]) { + virSocketAddr virAddr; + if (VIR_REALLOC_N(table->t, num + 1) < 0) + goto cleanup; + + table->n = num + 1; + + addr = RTA_DATA(tb[NDA_DST]); + bzero(&virAddr, sizeof(virAddr)); + virAddr.len = sizeof(virAddr.data.inet4); + virAddr.data.inet4.sin_family = AF_INET; + virAddr.data.inet4.sin_addr = *(struct in_addr *)addr; + ipstr = virSocketAddrFormat(&virAddr); + + if (VIR_STRDUP(table->t[num].ipaddr, ipstr) < 0) + goto cleanup; + + VIR_FREE(ipstr); + } + + if (tb[NDA_LLADDR]) { + virMacAddr macaddr; + char ifmac[VIR_MAC_STRING_BUFLEN]; + + addr = RTA_DATA(tb[NDA_LLADDR]); + memcpy(macaddr.addr, addr, VIR_MAC_BUFLEN); + macaddr.generated = false; + + virMacAddrFormat(&macaddr, ifmac); + + if (VIR_STRDUP(table->t[num].mac, ifmac) < 0) + goto cleanup; + + num++; + } + + next_nlmsg: + nh = NLMSG_NEXT(nh, msglen); + } + + end_of_netlink_messages: + VIR_FREE(nlData); + return table; + + cleanup: + VIR_FREE(ipstr); + VIR_FREE(nlData); + return NULL; +} + +#else + +virArpTablePtr virArpTableGet(void) +{ + virReportError(VIR_ERR_NO_SUPPORT, "%s", + _("get arp table not implemented on this platform")); + return NULL; +} + +#endif /* __linux__ */ + +void +virArpTableFree(virArpTablePtr table) +{ + size_t i; + for (i = 0; i < table->n; i++) { + VIR_FREE(table->t[i].ipaddr); + VIR_FREE(table->t[i].mac); + } + VIR_FREE(table); +} diff --git a/src/util/virarptable.h b/src/util/virarptable.h new file mode 100644 index 000000000..682919812 --- /dev/null +++ b/src/util/virarptable.h @@ -0,0 +1,47 @@ +/* + * virarptable.h Linux ARP table handling + * + * Copyright (C) 2018 Chen Hanxiao + * + * 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/>;. + * + * Authors: + * Chen Hanxiao <chenhanxiao(a)gmail.com&gt; + */ + +#ifndef __VIR_ARPTABLE_H__ +# define __VIR_ARPTABLE_H__ + +# include "internal.h" + +typedef struct _virArpTableEntry virArpTableEntry; +typedef virArpTableEntry *virArpTableEntryPtr; +typedef struct _virArpTable virArpTable; +typedef virArpTable *virArpTablePtr; + +struct _virArpTableEntry{ + char *ipaddr; + char *mac; +}; + +struct _virArpTable { + int n; + virArpTableEntryPtr t; +}; + +virArpTablePtr virArpTableGet(void); +void virArpTableFree(virArpTablePtr table); + +#endif /* __VIR_ARPTABLE_H__ */ -- 2.14.3