mirror of
https://github.com/systemd/systemd.git
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279 lines
8.2 KiB
C
279 lines
8.2 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <asm/types.h>
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#include <netinet/in.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <linux/netlink.h>
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#include <linux/rtnetlink.h>
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#include "util.h"
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#include "macro.h"
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#include "loopback-setup.h"
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enum {
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REQUEST_NONE = 0,
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REQUEST_ADDRESS_IPV4 = 1,
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REQUEST_ADDRESS_IPV6 = 2,
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REQUEST_FLAGS = 4,
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REQUEST_ALL = 7
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};
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#define NLMSG_TAIL(nmsg) \
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((struct rtattr *) (((uint8_t*) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
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static int add_rtattr(struct nlmsghdr *n, size_t max_length, int type, const void *data, size_t data_length) {
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size_t length;
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struct rtattr *rta;
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length = RTA_LENGTH(data_length);
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if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length) > max_length)
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return -E2BIG;
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rta = NLMSG_TAIL(n);
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rta->rta_type = type;
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rta->rta_len = length;
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memcpy(RTA_DATA(rta), data, data_length);
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n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length);
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return 0;
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}
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static ssize_t sendto_loop(int fd, const void *buf, size_t buf_len, int flags, const struct sockaddr *sa, socklen_t sa_len) {
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for (;;) {
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ssize_t l;
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if ((l = sendto(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
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return l;
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if (errno != EINTR)
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return -errno;
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}
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}
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static ssize_t recvfrom_loop(int fd, void *buf, size_t buf_len, int flags, struct sockaddr *sa, socklen_t *sa_len) {
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for (;;) {
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ssize_t l;
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if ((l = recvfrom(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
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return l;
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if (errno != EINTR)
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return -errno;
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}
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}
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static int add_adresses(int fd, int if_loopback) {
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union {
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struct sockaddr sa;
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struct sockaddr_nl nl;
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} sa;
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union {
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struct nlmsghdr header;
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uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
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NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
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RTA_LENGTH(sizeof(struct in6_addr))];
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} request;
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struct ifaddrmsg *ifaddrmsg;
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uint32_t ipv4_address = htonl(INADDR_LOOPBACK);
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int r;
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zero(request);
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request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
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request.header.nlmsg_type = RTM_NEWADDR;
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request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_ACK;
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request.header.nlmsg_seq = REQUEST_ADDRESS_IPV4;
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ifaddrmsg = NLMSG_DATA(&request.header);
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ifaddrmsg->ifa_family = AF_INET;
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ifaddrmsg->ifa_prefixlen = 8;
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ifaddrmsg->ifa_flags = IFA_F_PERMANENT;
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ifaddrmsg->ifa_scope = RT_SCOPE_HOST;
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ifaddrmsg->ifa_index = if_loopback;
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if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address))) < 0)
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return r;
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zero(sa);
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sa.nl.nl_family = AF_NETLINK;
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if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
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return -errno;
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request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
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request.header.nlmsg_seq = REQUEST_ADDRESS_IPV6;
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ifaddrmsg->ifa_family = AF_INET6;
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ifaddrmsg->ifa_prefixlen = 128;
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if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback))) < 0)
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return r;
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if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
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return -errno;
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return 0;
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}
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static int start_interface(int fd, int if_loopback) {
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union {
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struct sockaddr sa;
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struct sockaddr_nl nl;
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} sa;
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union {
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struct nlmsghdr header;
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uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
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NLMSG_ALIGN(sizeof(struct ifinfomsg))];
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} request;
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struct ifinfomsg *ifinfomsg;
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zero(request);
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request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
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request.header.nlmsg_type = RTM_NEWLINK;
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request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
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request.header.nlmsg_seq = REQUEST_FLAGS;
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ifinfomsg = NLMSG_DATA(&request.header);
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ifinfomsg->ifi_family = AF_UNSPEC;
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ifinfomsg->ifi_index = if_loopback;
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ifinfomsg->ifi_flags = IFF_UP;
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ifinfomsg->ifi_change = IFF_UP;
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zero(sa);
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sa.nl.nl_family = AF_NETLINK;
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if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
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return -errno;
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return 0;
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}
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static int read_response(int fd) {
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union {
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struct sockaddr sa;
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struct sockaddr_nl nl;
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} sa;
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union {
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struct nlmsghdr header;
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uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
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NLMSG_ALIGN(sizeof(struct nlmsgerr))];
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} response;
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ssize_t l;
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socklen_t sa_len = sizeof(sa);
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struct nlmsgerr *nlmsgerr;
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if ((l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len)) < 0)
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return -errno;
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if (sa_len != sizeof(sa.nl) ||
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sa.nl.nl_family != AF_NETLINK)
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return -EIO;
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if (sa.nl.nl_pid != 0)
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return 0;
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if ((size_t) l < sizeof(struct nlmsghdr))
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return -EIO;
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if (response.header.nlmsg_type != NLMSG_ERROR ||
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(pid_t) response.header.nlmsg_pid != getpid() ||
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response.header.nlmsg_seq >= REQUEST_ALL)
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return 0;
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if ((size_t) l < NLMSG_LENGTH(sizeof(struct nlmsgerr)) ||
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response.header.nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
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return -EIO;
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nlmsgerr = NLMSG_DATA(&response.header);
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if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST) {
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log_warning("Netlink failure for request %i: %s", response.header.nlmsg_seq, strerror(-nlmsgerr->error));
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return nlmsgerr->error;
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}
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return response.header.nlmsg_seq;
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}
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int loopback_setup(void) {
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int r, if_loopback;
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union {
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struct sockaddr sa;
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struct sockaddr_nl nl;
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struct sockaddr_storage storage;
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} sa;
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int requests = REQUEST_NONE;
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int fd;
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errno = 0;
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if ((if_loopback = (int) if_nametoindex("lo")) <= 0)
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return errno ? -errno : -ENODEV;
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if ((fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0)
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return -errno;
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zero(sa);
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sa.nl.nl_family = AF_NETLINK;
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if (bind(fd, &sa.sa, sizeof(sa)) < 0) {
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r = -errno;
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goto finish;
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}
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if ((r = add_adresses(fd, if_loopback)) < 0)
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goto finish;
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if ((r = start_interface(fd, if_loopback)) < 0)
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goto finish;
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do {
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if ((r = read_response(fd)) < 0)
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goto finish;
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requests |= r;
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} while (requests != REQUEST_ALL);
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r = 0;
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finish:
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if (r < 0)
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log_error("Failed to configure loopback device: %s", strerror(-r));
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if (fd >= 0)
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close_nointr_nofail(fd);
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return r;
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}
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