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
|
/* SPDX-License-Identifier: LGPL-2.1+ */
/***
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 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.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <net/if.h>
#include <stdlib.h>
#include "sd-netlink.h"
#include "loopback-setup.h"
#include "missing.h"
#include "netlink-util.h"
#define LOOPBACK_SETUP_TIMEOUT_USEC (5 * USEC_PER_SEC)
struct state {
unsigned n_messages;
int rcode;
const char *title;
};
static int generic_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) {
struct state *s = userdata;
assert(s);
assert(s->n_messages > 0);
s->n_messages--;
errno = 0;
log_debug_errno(sd_netlink_message_get_errno(m), "Failed to %s: %m", s->title);
s->rcode = sd_netlink_message_get_errno(m);
return 0;
}
static int start_loopback(sd_netlink *rtnl, struct state *s) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL;
int r;
assert(rtnl);
assert(s);
r = sd_rtnl_message_new_link(rtnl, &req, RTM_SETLINK, LOOPBACK_IFINDEX);
if (r < 0)
return r;
r = sd_rtnl_message_link_set_flags(req, IFF_UP, IFF_UP);
if (r < 0)
return r;
r = sd_netlink_call_async(rtnl, req, generic_handler, s, LOOPBACK_SETUP_TIMEOUT_USEC, NULL);
if (r < 0)
return r;
s->n_messages ++;
return 0;
}
static int add_ipv4_address(sd_netlink *rtnl, struct state *s) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL;
int r;
assert(rtnl);
assert(s);
r = sd_rtnl_message_new_addr(rtnl, &req, RTM_NEWADDR, LOOPBACK_IFINDEX, AF_INET);
if (r < 0)
return r;
r = sd_rtnl_message_addr_set_prefixlen(req, 8);
if (r < 0)
return r;
r = sd_rtnl_message_addr_set_flags(req, IFA_F_PERMANENT);
if (r < 0)
return r;
r = sd_rtnl_message_addr_set_scope(req, RT_SCOPE_HOST);
if (r < 0)
return r;
r = sd_netlink_message_append_in_addr(req, IFA_LOCAL, &(struct in_addr) { .s_addr = htobe32(INADDR_LOOPBACK) } );
if (r < 0)
return r;
r = sd_netlink_call_async(rtnl, req, generic_handler, s, USEC_INFINITY, NULL);
if (r < 0)
return r;
s->n_messages ++;
return 0;
}
static int add_ipv6_address(sd_netlink *rtnl, struct state *s) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL;
int r;
assert(rtnl);
assert(s);
r = sd_rtnl_message_new_addr(rtnl, &req, RTM_NEWADDR, LOOPBACK_IFINDEX, AF_INET6);
if (r < 0)
return r;
r = sd_rtnl_message_addr_set_prefixlen(req, 128);
if (r < 0)
return r;
r = sd_rtnl_message_addr_set_flags(req, IFA_F_PERMANENT);
if (r < 0)
return r;
r = sd_rtnl_message_addr_set_scope(req, RT_SCOPE_HOST);
if (r < 0)
return r;
r = sd_netlink_message_append_in6_addr(req, IFA_LOCAL, &in6addr_loopback);
if (r < 0)
return r;
r = sd_netlink_call_async(rtnl, req, generic_handler, s, USEC_INFINITY, NULL);
if (r < 0)
return r;
s->n_messages ++;
return 0;
}
static bool check_loopback(sd_netlink *rtnl) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
unsigned flags;
int r;
r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, LOOPBACK_IFINDEX);
if (r < 0)
return false;
r = sd_netlink_call(rtnl, req, USEC_INFINITY, &reply);
if (r < 0)
return false;
r = sd_rtnl_message_link_get_flags(reply, &flags);
if (r < 0)
return false;
return flags & IFF_UP;
}
int loopback_setup(void) {
_cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
struct state state_4 = { .title = "add address 127.0.0.1 to loopback interface" },
state_6 = { .title = "add address ::1 to loopback interface"},
state_up = { .title = "bring loopback interface up" };
int r;
r = sd_netlink_open(&rtnl);
if (r < 0)
return log_error_errno(r, "Failed to open netlink: %m");
/* Note that we add the IP addresses here explicitly even though the kernel does that too implicitly when
* setting up the loopback device. The reason we do this here a second time (and possibly race against the
* kernel) is that we want to synchronously wait until the IP addresses are set up correctly, see
*
* https://github.com/systemd/systemd/issues/5641 */
r = add_ipv4_address(rtnl, &state_4);
if (r < 0)
return log_error_errno(r, "Failed to enqueue IPv4 loopback address add request: %m");
r = add_ipv6_address(rtnl, &state_6);
if (r < 0)
return log_error_errno(r, "Failed to enqueue IPv6 loopback address add request: %m");
r = start_loopback(rtnl, &state_up);
if (r < 0)
return log_error_errno(r, "Failed to enqueue loopback interface start request: %m");
while (state_4.n_messages + state_6.n_messages + state_up.n_messages > 0) {
r = sd_netlink_wait(rtnl, LOOPBACK_SETUP_TIMEOUT_USEC);
if (r < 0)
return log_error_errno(r, "Failed to wait for netlink event: %m");
r = sd_netlink_process(rtnl, NULL);
if (r < 0)
return log_warning_errno(r, "Failed to process netlink event: %m");
}
/* Note that we don't really care whether the addresses could be added or not */
if (state_up.rcode != 0) {
/* If we lack the permissions to configure the loopback device,
* but we find it to be already configured, let's exit cleanly,
* in order to supported unprivileged containers. */
if (state_up.rcode == -EPERM && check_loopback(rtnl))
return 0;
return log_warning_errno(state_up.rcode, "Failed to configure loopback device: %m");
}
return 0;
}
|