1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
|
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <sys/socket.h>
#include <net/if.h>
#include <asm/types.h>
#include <netinet/in.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include "util.h"
#include "macro.h"
#include "loopback-setup.h"
#include "socket-util.h"
#define NLMSG_TAIL(nmsg) \
((struct rtattr *) (((uint8_t*) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
static int add_rtattr(struct nlmsghdr *n, size_t max_length, int type, const void *data, size_t data_length) {
size_t length;
struct rtattr *rta;
length = RTA_LENGTH(data_length);
if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length) > max_length)
return -E2BIG;
rta = NLMSG_TAIL(n);
rta->rta_type = type;
rta->rta_len = length;
memcpy(RTA_DATA(rta), data, data_length);
n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length);
return 0;
}
static ssize_t sendto_loop(int fd, const void *buf, size_t buf_len, int flags, const struct sockaddr *sa, socklen_t sa_len) {
for (;;) {
ssize_t l;
if ((l = sendto(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
return l;
if (errno != EINTR)
return -errno;
}
}
static ssize_t recvfrom_loop(int fd, void *buf, size_t buf_len, int flags, struct sockaddr *sa, socklen_t *sa_len) {
for (;;) {
ssize_t l;
if ((l = recvfrom(fd, buf, buf_len, flags, sa, sa_len)) >= 0)
return l;
if (errno != EINTR)
return -errno;
}
}
static int add_adresses(int fd, int if_loopback, unsigned *requests) {
union {
struct sockaddr sa;
struct sockaddr_nl nl;
} sa;
union {
struct nlmsghdr header;
uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
RTA_LENGTH(sizeof(struct in6_addr))];
} request;
struct ifaddrmsg *ifaddrmsg;
uint32_t ipv4_address = htonl(INADDR_LOOPBACK);
int r;
zero(request);
request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
request.header.nlmsg_type = RTM_NEWADDR;
request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_ACK;
request.header.nlmsg_seq = *requests + 1;
ifaddrmsg = NLMSG_DATA(&request.header);
ifaddrmsg->ifa_family = AF_INET;
ifaddrmsg->ifa_prefixlen = 8;
ifaddrmsg->ifa_flags = IFA_F_PERMANENT;
ifaddrmsg->ifa_scope = RT_SCOPE_HOST;
ifaddrmsg->ifa_index = if_loopback;
if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address))) < 0)
return r;
zero(sa);
sa.nl.nl_family = AF_NETLINK;
if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
return -errno;
(*requests)++;
if (!socket_ipv6_is_supported())
return 0;
request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
request.header.nlmsg_seq = *requests + 1;
ifaddrmsg->ifa_family = AF_INET6;
ifaddrmsg->ifa_prefixlen = 128;
if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback))) < 0)
return r;
if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
return -errno;
(*requests)++;
return 0;
}
static int start_interface(int fd, int if_loopback, unsigned *requests) {
union {
struct sockaddr sa;
struct sockaddr_nl nl;
} sa;
union {
struct nlmsghdr header;
uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct ifinfomsg))];
} request;
struct ifinfomsg *ifinfomsg;
zero(request);
request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
request.header.nlmsg_type = RTM_NEWLINK;
request.header.nlmsg_flags = NLM_F_REQUEST|NLM_F_ACK;
request.header.nlmsg_seq = *requests + 1;
ifinfomsg = NLMSG_DATA(&request.header);
ifinfomsg->ifi_family = AF_UNSPEC;
ifinfomsg->ifi_index = if_loopback;
ifinfomsg->ifi_flags = IFF_UP;
ifinfomsg->ifi_change = IFF_UP;
zero(sa);
sa.nl.nl_family = AF_NETLINK;
if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0)
return -errno;
(*requests)++;
return 0;
}
static int read_response(int fd, unsigned requests_max) {
union {
struct sockaddr sa;
struct sockaddr_nl nl;
} sa;
union {
struct nlmsghdr header;
uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct nlmsgerr))];
} response;
ssize_t l;
socklen_t sa_len = sizeof(sa);
struct nlmsgerr *nlmsgerr;
if ((l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len)) < 0)
return -errno;
if (sa_len != sizeof(sa.nl) ||
sa.nl.nl_family != AF_NETLINK)
return -EIO;
if (sa.nl.nl_pid != 0)
return 0;
if ((size_t) l < sizeof(struct nlmsghdr))
return -EIO;
if (response.header.nlmsg_type != NLMSG_ERROR ||
(pid_t) response.header.nlmsg_pid != getpid() ||
response.header.nlmsg_seq >= requests_max)
return 0;
if ((size_t) l < NLMSG_LENGTH(sizeof(struct nlmsgerr)) ||
response.header.nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
return -EIO;
nlmsgerr = NLMSG_DATA(&response.header);
if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST) {
log_warning("Netlink failure for request %i: %s", response.header.nlmsg_seq, strerror(-nlmsgerr->error));
return nlmsgerr->error;
}
return response.header.nlmsg_seq;
}
int loopback_setup(void) {
int r, if_loopback;
union {
struct sockaddr sa;
struct sockaddr_nl nl;
struct sockaddr_storage storage;
} sa;
unsigned requests = 0, i;
int fd;
errno = 0;
if ((if_loopback = (int) if_nametoindex("lo")) <= 0)
return errno ? -errno : -ENODEV;
if ((fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0)
return -errno;
zero(sa);
sa.nl.nl_family = AF_NETLINK;
if (bind(fd, &sa.sa, sizeof(sa)) < 0) {
r = -errno;
goto finish;
}
if ((r = add_adresses(fd, if_loopback, &requests)) < 0)
goto finish;
if ((r = start_interface(fd, if_loopback, &requests)) < 0)
goto finish;
for (i = 0; i < requests; i++) {
if ((r = read_response(fd, requests)) < 0)
goto finish;
}
r = 0;
finish:
if (r < 0)
log_error("Failed to configure loopback device: %s", strerror(-r));
if (fd >= 0)
close_nointr_nofail(fd);
return r;
}
|
