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d6c9574f | 1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
af5bc85d LP |
2 | |
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
5430f7f2 LP |
9 | under the terms of the GNU Lesser General Public License as published by |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
af5bc85d LP |
11 | (at your option) any later version. |
12 | ||
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 | |
5430f7f2 | 16 | Lesser General Public License for more details. |
af5bc85d | 17 | |
5430f7f2 | 18 | You should have received a copy of the GNU Lesser General Public License |
af5bc85d LP |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
20 | ***/ | |
21 | ||
22 | #include <errno.h> | |
23 | #include <sys/socket.h> | |
24 | #include <net/if.h> | |
25 | #include <asm/types.h> | |
26 | #include <netinet/in.h> | |
27 | #include <string.h> | |
28 | #include <stdlib.h> | |
29 | #include <unistd.h> | |
30 | #include <linux/netlink.h> | |
31 | #include <linux/rtnetlink.h> | |
32 | ||
33 | #include "util.h" | |
34 | #include "macro.h" | |
35 | #include "loopback-setup.h" | |
5bfcc1c6 | 36 | #include "socket-util.h" |
af5bc85d LP |
37 | |
38 | #define NLMSG_TAIL(nmsg) \ | |
39 | ((struct rtattr *) (((uint8_t*) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len))) | |
40 | ||
41 | static int add_rtattr(struct nlmsghdr *n, size_t max_length, int type, const void *data, size_t data_length) { | |
42 | size_t length; | |
43 | struct rtattr *rta; | |
44 | ||
45 | length = RTA_LENGTH(data_length); | |
46 | ||
47 | if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(length) > max_length) | |
48 | return -E2BIG; | |
49 | ||
50 | rta = NLMSG_TAIL(n); | |
51 | rta->rta_type = type; | |
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); | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
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) { | |
60 | ||
61 | for (;;) { | |
62 | ssize_t l; | |
63 | ||
64 | if ((l = sendto(fd, buf, buf_len, flags, sa, sa_len)) >= 0) | |
65 | return l; | |
66 | ||
67 | if (errno != EINTR) | |
68 | return -errno; | |
69 | } | |
70 | } | |
71 | ||
72 | static ssize_t recvfrom_loop(int fd, void *buf, size_t buf_len, int flags, struct sockaddr *sa, socklen_t *sa_len) { | |
73 | ||
74 | for (;;) { | |
75 | ssize_t l; | |
76 | ||
77 | if ((l = recvfrom(fd, buf, buf_len, flags, sa, sa_len)) >= 0) | |
78 | return l; | |
79 | ||
80 | if (errno != EINTR) | |
81 | return -errno; | |
82 | } | |
83 | } | |
84 | ||
5bfcc1c6 | 85 | static int add_adresses(int fd, int if_loopback, unsigned *requests) { |
af5bc85d LP |
86 | union { |
87 | struct sockaddr sa; | |
88 | struct sockaddr_nl nl; | |
89 | } sa; | |
90 | union { | |
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))]; | |
95 | } request; | |
96 | ||
97 | struct ifaddrmsg *ifaddrmsg; | |
98 | uint32_t ipv4_address = htonl(INADDR_LOOPBACK); | |
99 | int r; | |
100 | ||
101 | zero(request); | |
102 | ||
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; | |
5bfcc1c6 | 106 | request.header.nlmsg_seq = *requests + 1; |
af5bc85d LP |
107 | |
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; | |
114 | ||
115 | if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &ipv4_address, sizeof(ipv4_address))) < 0) | |
116 | return r; | |
117 | ||
118 | zero(sa); | |
119 | sa.nl.nl_family = AF_NETLINK; | |
120 | ||
121 | if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0) | |
122 | return -errno; | |
5bfcc1c6 FF |
123 | (*requests)++; |
124 | ||
125 | if (!socket_ipv6_is_supported()) | |
126 | return 0; | |
af5bc85d LP |
127 | |
128 | request.header.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg)); | |
5bfcc1c6 | 129 | request.header.nlmsg_seq = *requests + 1; |
af5bc85d LP |
130 | |
131 | ifaddrmsg->ifa_family = AF_INET6; | |
132 | ifaddrmsg->ifa_prefixlen = 128; | |
133 | ||
134 | if ((r = add_rtattr(&request.header, sizeof(request), IFA_LOCAL, &in6addr_loopback, sizeof(in6addr_loopback))) < 0) | |
135 | return r; | |
136 | ||
137 | if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0) | |
138 | return -errno; | |
5bfcc1c6 | 139 | (*requests)++; |
af5bc85d LP |
140 | |
141 | return 0; | |
142 | } | |
143 | ||
5bfcc1c6 | 144 | static int start_interface(int fd, int if_loopback, unsigned *requests) { |
af5bc85d LP |
145 | union { |
146 | struct sockaddr sa; | |
147 | struct sockaddr_nl nl; | |
148 | } sa; | |
149 | union { | |
150 | struct nlmsghdr header; | |
151 | uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + | |
152 | NLMSG_ALIGN(sizeof(struct ifinfomsg))]; | |
153 | } request; | |
154 | ||
155 | struct ifinfomsg *ifinfomsg; | |
156 | ||
157 | zero(request); | |
158 | ||
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; | |
5bfcc1c6 | 162 | request.header.nlmsg_seq = *requests + 1; |
af5bc85d LP |
163 | |
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; | |
169 | ||
170 | zero(sa); | |
171 | sa.nl.nl_family = AF_NETLINK; | |
172 | ||
173 | if (sendto_loop(fd, &request, request.header.nlmsg_len, 0, &sa.sa, sizeof(sa)) < 0) | |
174 | return -errno; | |
175 | ||
5bfcc1c6 FF |
176 | (*requests)++; |
177 | ||
af5bc85d LP |
178 | return 0; |
179 | } | |
180 | ||
5bfcc1c6 | 181 | static int read_response(int fd, unsigned requests_max) { |
af5bc85d LP |
182 | union { |
183 | struct sockaddr sa; | |
184 | struct sockaddr_nl nl; | |
185 | } sa; | |
186 | union { | |
187 | struct nlmsghdr header; | |
188 | uint8_t buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + | |
189 | NLMSG_ALIGN(sizeof(struct nlmsgerr))]; | |
190 | } response; | |
191 | ||
192 | ssize_t l; | |
193 | socklen_t sa_len = sizeof(sa); | |
194 | struct nlmsgerr *nlmsgerr; | |
195 | ||
196 | if ((l = recvfrom_loop(fd, &response, sizeof(response), 0, &sa.sa, &sa_len)) < 0) | |
197 | return -errno; | |
198 | ||
199 | if (sa_len != sizeof(sa.nl) || | |
200 | sa.nl.nl_family != AF_NETLINK) | |
201 | return -EIO; | |
202 | ||
203 | if (sa.nl.nl_pid != 0) | |
204 | return 0; | |
205 | ||
206 | if ((size_t) l < sizeof(struct nlmsghdr)) | |
207 | return -EIO; | |
208 | ||
209 | if (response.header.nlmsg_type != NLMSG_ERROR || | |
210 | (pid_t) response.header.nlmsg_pid != getpid() || | |
5bfcc1c6 | 211 | response.header.nlmsg_seq >= requests_max) |
af5bc85d LP |
212 | return 0; |
213 | ||
214 | if ((size_t) l < NLMSG_LENGTH(sizeof(struct nlmsgerr)) || | |
215 | response.header.nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) | |
216 | return -EIO; | |
217 | ||
218 | nlmsgerr = NLMSG_DATA(&response.header); | |
219 | ||
86700cf7 | 220 | if (nlmsgerr->error < 0 && nlmsgerr->error != -EEXIST) { |
68d157d8 | 221 | log_warning("Netlink failure for request %i: %s", response.header.nlmsg_seq, strerror(-nlmsgerr->error)); |
af5bc85d | 222 | return nlmsgerr->error; |
86700cf7 | 223 | } |
af5bc85d LP |
224 | |
225 | return response.header.nlmsg_seq; | |
226 | } | |
227 | ||
228 | int loopback_setup(void) { | |
229 | int r, if_loopback; | |
230 | union { | |
231 | struct sockaddr sa; | |
232 | struct sockaddr_nl nl; | |
233 | struct sockaddr_storage storage; | |
234 | } sa; | |
5bfcc1c6 | 235 | unsigned requests = 0, i; |
af5bc85d LP |
236 | int fd; |
237 | ||
238 | errno = 0; | |
239 | if ((if_loopback = (int) if_nametoindex("lo")) <= 0) | |
240 | return errno ? -errno : -ENODEV; | |
241 | ||
242 | if ((fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) < 0) | |
243 | return -errno; | |
244 | ||
245 | zero(sa); | |
246 | sa.nl.nl_family = AF_NETLINK; | |
247 | ||
248 | if (bind(fd, &sa.sa, sizeof(sa)) < 0) { | |
249 | r = -errno; | |
250 | goto finish; | |
251 | } | |
252 | ||
5bfcc1c6 | 253 | if ((r = add_adresses(fd, if_loopback, &requests)) < 0) |
af5bc85d LP |
254 | goto finish; |
255 | ||
5bfcc1c6 | 256 | if ((r = start_interface(fd, if_loopback, &requests)) < 0) |
af5bc85d LP |
257 | goto finish; |
258 | ||
5bfcc1c6 FF |
259 | for (i = 0; i < requests; i++) { |
260 | if ((r = read_response(fd, requests)) < 0) | |
af5bc85d | 261 | goto finish; |
5bfcc1c6 | 262 | } |
af5bc85d LP |
263 | |
264 | r = 0; | |
265 | ||
266 | finish: | |
267 | if (r < 0) | |
a2c422cb | 268 | log_warning("Failed to configure loopback device: %s", strerror(-r)); |
af5bc85d LP |
269 | |
270 | if (fd >= 0) | |
271 | close_nointr_nofail(fd); | |
272 | ||
273 | return r; | |
274 | } |