1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2010 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
23 #include <sys/socket.h>
25 #include <asm/types.h>
26 #include <netinet/in.h>
30 #include <linux/netlink.h>
31 #include <linux/rtnetlink.h>
35 #include "loopback-setup.h"
36 #include "socket-util.h"
38 #define NLMSG_TAIL(nmsg) \
39 ((struct rtattr *) (((uint8_t*) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
41 static int add_rtattr(struct nlmsghdr *n, size_t max_length, int type, const void *data, size_t data_length) {
45 length = RTA_LENGTH(data_length);
47 if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length) > max_length)
52 rta->rta_len = length;
53 memcpy(RTA_DATA(rta), data, data_length);
54 n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length);
59 static ssize_t sendto_loop(int fd, const void *buf, size_t buf_len, int flags, const struct sockaddr *sa, socklen_t sa_len) {
64 if ((l = sendto(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
72 static ssize_t recvfrom_loop(int fd, void *buf, size_t buf_len, int flags, struct sockaddr *sa, socklen_t *sa_len) {
77 if ((l = recvfrom(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
85 static int add_adresses(int fd, int if_loopback, unsigned *requests) {
88 struct sockaddr_nl nl;
91 struct nlmsghdr header;
92 uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
93 NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
94 RTA_LENGTH(sizeof(struct in6_addr))];
97 struct ifaddrmsg *ifaddrmsg;
98 uint32_t ipv4_address = htonl(INADDR_LOOPBACK);
103 request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
104 request.header.nlmsg_type = RTM_NEWADDR;
105 request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_ACK;
106 request.header.nlmsg_seq = *requests + 1;
108 ifaddrmsg = NLMSG_DATA(&request.header);
109 ifaddrmsg->ifa_family = AF_INET;
110 ifaddrmsg->ifa_prefixlen = 8;
111 ifaddrmsg->ifa_flags = IFA_F_PERMANENT;
112 ifaddrmsg->ifa_scope = RT_SCOPE_HOST;
113 ifaddrmsg->ifa_index = if_loopback;
115 if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address))) < 0)
119 sa.nl.nl_family = AF_NETLINK;
121 if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
125 if (!socket_ipv6_is_supported())
128 request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
129 request.header.nlmsg_seq = *requests + 1;
131 ifaddrmsg->ifa_family = AF_INET6;
132 ifaddrmsg->ifa_prefixlen = 128;
134 if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback))) < 0)
137 if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
144 static int start_interface(int fd, int if_loopback, unsigned *requests) {
147 struct sockaddr_nl nl;
150 struct nlmsghdr header;
151 uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
152 NLMSG_ALIGN(sizeof(struct ifinfomsg))];
155 struct ifinfomsg *ifinfomsg;
159 request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
160 request.header.nlmsg_type = RTM_NEWLINK;
161 request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
162 request.header.nlmsg_seq = *requests + 1;
164 ifinfomsg = NLMSG_DATA(&request.header);
165 ifinfomsg->ifi_family = AF_UNSPEC;
166 ifinfomsg->ifi_index = if_loopback;
167 ifinfomsg->ifi_flags = IFF_UP;
168 ifinfomsg->ifi_change = IFF_UP;
171 sa.nl.nl_family = AF_NETLINK;
173 if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
181 static int read_response(int fd, unsigned requests_max) {
184 struct sockaddr_nl nl;
187 struct nlmsghdr header;
188 uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
189 NLMSG_ALIGN(sizeof(struct nlmsgerr))];
193 socklen_t sa_len = sizeof(sa);
194 struct nlmsgerr *nlmsgerr;
196 if ((l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len)) < 0)
199 if (sa_len != sizeof(sa.nl) ||
200 sa.nl.nl_family != AF_NETLINK)
203 if (sa.nl.nl_pid != 0)
206 if ((size_t) l < sizeof(struct nlmsghdr))
209 if (response.header.nlmsg_type != NLMSG_ERROR ||
210 (pid_t) response.header.nlmsg_pid != getpid() ||
211 response.header.nlmsg_seq >= requests_max)
214 if ((size_t) l < NLMSG_LENGTH(sizeof(struct nlmsgerr)) ||
215 response.header.nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
218 nlmsgerr = NLMSG_DATA(&response.header);
220 if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST) {
221 log_warning("Netlink failure for request %i: %s", response.header.nlmsg_seq, strerror(-nlmsgerr->error));
222 return nlmsgerr->error;
225 return response.header.nlmsg_seq;
228 int loopback_setup(void) {
232 struct sockaddr_nl nl;
233 struct sockaddr_storage storage;
235 unsigned requests = 0, i;
239 if ((if_loopback = (int) if_nametoindex("lo")) <= 0)
240 return errno ? -errno : -ENODEV;
242 if ((fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0)
246 sa.nl.nl_family = AF_NETLINK;
248 if (bind(fd, &sa.sa, sizeof(sa)) < 0) {
253 if ((r = add_adresses(fd, if_loopback, &requests)) < 0)
256 if ((r = start_interface(fd, if_loopback, &requests)) < 0)
259 for (i = 0; i < requests; i++) {
260 if ((r = read_response(fd, requests)) < 0)
268 log_error("Failed to configure loopback device: %s", strerror(-r));
271 close_nointr_nofail(fd);