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05895ad0 PG |
1 | /* zebra NETNS ID handling routines |
2 | * those routines are implemented locally to avoid having external dependencies. | |
3 | * Copyright (C) 2018 6WIND | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License as published by the Free | |
7 | * Software Foundation; either version 2 of the License, or (at your option) | |
8 | * any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along | |
16 | * with this program; see the file COPYING; if not, write to the Free Software | |
17 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | */ | |
19 | ||
20 | #include <zebra.h> | |
21 | ||
22 | #include "ns.h" | |
ec31f30d | 23 | #include "vrf.h" |
05895ad0 PG |
24 | #include "log.h" |
25 | ||
26 | #if defined(HAVE_NETLINK) | |
27 | ||
28 | #include <linux/net_namespace.h> | |
29 | #include <linux/netlink.h> | |
30 | #include <linux/rtnetlink.h> | |
31 | ||
32 | #include "rib.h" | |
33 | #include "zebra_ns.h" | |
34 | #include "kernel_netlink.h" | |
35 | #endif /* defined(HAVE_NETLINK) */ | |
36 | ||
37 | #include "zebra_netns_id.h" | |
38 | ||
ec31f30d PG |
39 | /* default NS ID value used when VRF backend is not NETNS */ |
40 | #define NS_DEFAULT_INTERNAL 0 | |
41 | ||
05895ad0 PG |
42 | /* in case NEWNSID not available, the NSID will be locally obtained |
43 | */ | |
44 | #define NS_BASE_NSID 0 | |
45 | ||
46 | #if defined(HAVE_NETLINK) | |
47 | ||
48 | #define NETLINK_SOCKET_BUFFER_SIZE 512 | |
49 | #define NETLINK_ALIGNTO 4 | |
996c9314 LB |
50 | #define NETLINK_ALIGN(len) \ |
51 | (((len) + NETLINK_ALIGNTO - 1) & ~(NETLINK_ALIGNTO - 1)) | |
05895ad0 PG |
52 | #define NETLINK_NLATTR_LEN(_a, _b) (unsigned int)((char *)_a - (char *)_b) |
53 | ||
54 | #endif /* defined(HAVE_NETLINK) */ | |
55 | ||
56 | static ns_id_t zebra_ns_id_get_fallback(const char *netnspath) | |
57 | { | |
58 | static int zebra_ns_id_local; | |
59 | ||
60 | return zebra_ns_id_local++; | |
61 | } | |
62 | ||
63 | #if defined(HAVE_NETLINK) | |
64 | ||
65 | static struct nlmsghdr *initiate_nlh(char *buf, unsigned int *seq, int type) | |
66 | { | |
67 | struct nlmsghdr *nlh; | |
68 | ||
69 | nlh = (struct nlmsghdr *)buf; | |
70 | nlh->nlmsg_len = NETLINK_ALIGN(sizeof(struct nlmsghdr)); | |
71 | ||
72 | nlh->nlmsg_type = type; | |
73 | nlh->nlmsg_flags = NLM_F_REQUEST; | |
74 | if (type == RTM_NEWNSID) | |
75 | nlh->nlmsg_flags |= NLM_F_ACK; | |
76 | nlh->nlmsg_seq = *seq = time(NULL); | |
77 | return nlh; | |
78 | } | |
79 | ||
996c9314 LB |
80 | static int send_receive(int sock, struct nlmsghdr *nlh, unsigned int seq, |
81 | char *buf) | |
05895ad0 PG |
82 | { |
83 | int ret; | |
996c9314 | 84 | static const struct sockaddr_nl snl = {.nl_family = AF_NETLINK}; |
05895ad0 PG |
85 | |
86 | ret = sendto(sock, (const void *)nlh, (size_t)nlh->nlmsg_len, 0, | |
996c9314 | 87 | (struct sockaddr *)&snl, (socklen_t)sizeof(snl)); |
05895ad0 | 88 | if (ret < 0) { |
996c9314 LB |
89 | zlog_err("netlink( %u) sendmsg() error: %s", sock, |
90 | safe_strerror(errno)); | |
05895ad0 PG |
91 | return -1; |
92 | } | |
93 | ||
94 | /* reception */ | |
95 | struct sockaddr_nl addr; | |
96 | struct iovec iov = { | |
996c9314 | 97 | .iov_base = buf, .iov_len = NETLINK_SOCKET_BUFFER_SIZE, |
05895ad0 PG |
98 | }; |
99 | struct msghdr msg = { | |
996c9314 LB |
100 | .msg_name = &addr, |
101 | .msg_namelen = sizeof(struct sockaddr_nl), | |
102 | .msg_iov = &iov, | |
103 | .msg_iovlen = 1, | |
104 | .msg_control = NULL, | |
05895ad0 | 105 | .msg_controllen = 0, |
996c9314 | 106 | .msg_flags = 0, |
05895ad0 PG |
107 | }; |
108 | ret = recvmsg(sock, &msg, 0); | |
109 | if (ret < 0) { | |
110 | zlog_err("netlink recvmsg: error %d (errno %u)", ret, errno); | |
111 | return -1; | |
112 | } | |
113 | if (msg.msg_flags & MSG_TRUNC) { | |
114 | zlog_err("netlink recvmsg : error message truncated"); | |
115 | return -1; | |
116 | } | |
117 | /* nlh already points to buf */ | |
118 | if (nlh->nlmsg_seq != seq) { | |
996c9314 LB |
119 | zlog_err( |
120 | "netlink recvmsg: bad sequence number %x (expected %x)", | |
121 | seq, nlh->nlmsg_seq); | |
05895ad0 PG |
122 | return -1; |
123 | } | |
124 | return ret; | |
125 | } | |
126 | ||
127 | /* extract on a valid nlmsg the nsid | |
128 | * valid nlmsghdr - not a nlmsgerr | |
129 | */ | |
130 | static ns_id_t extract_nsid(struct nlmsghdr *nlh, char *buf) | |
131 | { | |
132 | ns_id_t ns_id = NS_UNKNOWN; | |
996c9314 LB |
133 | int offset = NETLINK_ALIGN(sizeof(struct nlmsghdr)) |
134 | + NETLINK_ALIGN(sizeof(struct rtgenmsg)); | |
05895ad0 PG |
135 | int curr_length = offset; |
136 | void *tail = (void *)((char *)nlh + NETLINK_ALIGN(nlh->nlmsg_len)); | |
137 | struct nlattr *attr; | |
138 | ||
139 | for (attr = (struct nlattr *)((char *)buf + offset); | |
996c9314 LB |
140 | NETLINK_NLATTR_LEN(tail, attr) >= sizeof(struct nlattr) |
141 | && attr->nla_len >= sizeof(struct nlattr) | |
142 | && attr->nla_len <= NETLINK_NLATTR_LEN(tail, attr); | |
05895ad0 PG |
143 | attr += NETLINK_ALIGN(attr->nla_len)) { |
144 | curr_length += attr->nla_len; | |
145 | if ((attr->nla_type & NLA_TYPE_MASK) == NETNSA_NSID) { | |
146 | u_int32_t *ptr = (u_int32_t *)(attr); | |
147 | ||
148 | ns_id = ptr[1]; | |
149 | break; | |
150 | } | |
151 | } | |
152 | return ns_id; | |
153 | } | |
154 | ||
155 | ns_id_t zebra_ns_id_get(const char *netnspath) | |
156 | { | |
157 | int ns_id = -1; | |
158 | struct sockaddr_nl snl; | |
159 | int fd, sock, ret; | |
160 | unsigned int seq; | |
161 | ns_id_t return_nsid = NS_UNKNOWN; | |
162 | ||
163 | /* netns path check */ | |
164 | if (!netnspath) | |
165 | return NS_UNKNOWN; | |
166 | fd = open(netnspath, O_RDONLY); | |
167 | if (fd == -1) | |
168 | return NS_UNKNOWN; | |
169 | ||
170 | /* netlink socket */ | |
171 | sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); | |
172 | if (sock < 0) { | |
996c9314 LB |
173 | zlog_err("netlink( %u) socket() error: %s", sock, |
174 | safe_strerror(errno)); | |
05895ad0 PG |
175 | return NS_UNKNOWN; |
176 | } | |
177 | memset(&snl, 0, sizeof(snl)); | |
178 | snl.nl_family = AF_NETLINK; | |
179 | snl.nl_groups = RTNLGRP_NSID; | |
180 | snl.nl_pid = 0; /* AUTO PID */ | |
181 | ret = bind(sock, (struct sockaddr *)&snl, sizeof(snl)); | |
182 | if (ret < 0) { | |
996c9314 LB |
183 | zlog_err("netlink( %u) socket() bind error: %s", sock, |
184 | safe_strerror(errno)); | |
05895ad0 PG |
185 | close(sock); |
186 | close(fd); | |
187 | return NS_UNKNOWN; | |
188 | } | |
189 | ||
190 | /* message to send to netlink,and response : NEWNSID */ | |
191 | char buf[NETLINK_SOCKET_BUFFER_SIZE]; | |
192 | struct nlmsghdr *nlh; | |
193 | struct rtgenmsg *rt; | |
194 | int len; | |
195 | ||
196 | memset(buf, 0, NETLINK_SOCKET_BUFFER_SIZE); | |
197 | nlh = initiate_nlh(buf, &seq, RTM_NEWNSID); | |
198 | rt = (struct rtgenmsg *)(buf + nlh->nlmsg_len); | |
199 | nlh->nlmsg_len += NETLINK_ALIGN(sizeof(struct rtgenmsg)); | |
200 | rt->rtgen_family = AF_UNSPEC; | |
201 | ||
202 | addattr32(nlh, NETLINK_SOCKET_BUFFER_SIZE, NETNSA_FD, fd); | |
203 | addattr32(nlh, NETLINK_SOCKET_BUFFER_SIZE, NETNSA_NSID, ns_id); | |
204 | ||
205 | ret = send_receive(sock, nlh, seq, buf); | |
206 | if (ret < 0) { | |
207 | close(sock); | |
208 | close(fd); | |
209 | return NS_UNKNOWN; | |
210 | } | |
211 | nlh = (struct nlmsghdr *)buf; | |
212 | ||
213 | /* message to analyse : NEWNSID response */ | |
214 | len = ret; | |
215 | ret = 0; | |
216 | do { | |
217 | if (nlh->nlmsg_type >= NLMSG_MIN_TYPE) { | |
218 | return_nsid = extract_nsid(nlh, buf); | |
219 | if (return_nsid != NS_UNKNOWN) | |
220 | break; | |
221 | } else { | |
222 | if (nlh->nlmsg_type == NLMSG_ERROR) { | |
996c9314 LB |
223 | struct nlmsgerr *err = |
224 | (struct nlmsgerr | |
225 | *)((char *)nlh | |
226 | + NETLINK_ALIGN(sizeof( | |
227 | struct | |
228 | nlmsghdr))); | |
05895ad0 PG |
229 | |
230 | ret = -1; | |
231 | if (err->error < 0) | |
232 | errno = -err->error; | |
233 | else | |
234 | errno = err->error; | |
235 | if (errno == 0) { | |
236 | /* request NEWNSID was successfull | |
237 | * return EEXIST error to get GETNSID | |
238 | */ | |
239 | errno = EEXIST; | |
240 | } | |
241 | } else { | |
242 | /* other errors ignored | |
243 | * attempt to get nsid | |
244 | */ | |
245 | ret = -1; | |
246 | errno = EEXIST; | |
247 | break; | |
248 | } | |
249 | } | |
250 | len = len - NETLINK_ALIGN(nlh->nlmsg_len); | |
996c9314 LB |
251 | nlh = (struct nlmsghdr *)((char *)nlh |
252 | + NETLINK_ALIGN(nlh->nlmsg_len)); | |
05895ad0 PG |
253 | } while (len != 0 && return_nsid != NS_UNKNOWN && ret == 0); |
254 | ||
255 | if (ret <= 0) { | |
256 | if (errno != EEXIST && ret != 0) { | |
996c9314 LB |
257 | zlog_err( |
258 | "netlink( %u) recvfrom() error 2 when reading: %s", | |
259 | fd, safe_strerror(errno)); | |
05895ad0 PG |
260 | close(sock); |
261 | close(fd); | |
262 | if (errno == ENOTSUP) { | |
263 | zlog_warn("NEWNSID locally generated"); | |
264 | return zebra_ns_id_get_fallback(netnspath); | |
265 | } | |
266 | return NS_UNKNOWN; | |
267 | } | |
268 | /* message to send to netlink : GETNSID */ | |
269 | memset(buf, 0, NETLINK_SOCKET_BUFFER_SIZE); | |
270 | nlh = initiate_nlh(buf, &seq, RTM_GETNSID); | |
271 | rt = (struct rtgenmsg *)(buf + nlh->nlmsg_len); | |
272 | nlh->nlmsg_len += NETLINK_ALIGN(sizeof(struct rtgenmsg)); | |
273 | rt->rtgen_family = AF_UNSPEC; | |
274 | ||
275 | addattr32(nlh, NETLINK_SOCKET_BUFFER_SIZE, NETNSA_FD, fd); | |
276 | addattr32(nlh, NETLINK_SOCKET_BUFFER_SIZE, NETNSA_NSID, ns_id); | |
277 | ||
278 | ret = send_receive(sock, nlh, seq, buf); | |
279 | if (ret < 0) { | |
280 | close(sock); | |
281 | close(fd); | |
282 | return NS_UNKNOWN; | |
283 | } | |
284 | nlh = (struct nlmsghdr *)buf; | |
285 | len = ret; | |
286 | ret = 0; | |
287 | do { | |
288 | if (nlh->nlmsg_type >= NLMSG_MIN_TYPE) { | |
289 | return_nsid = extract_nsid(nlh, buf); | |
290 | if (return_nsid != NS_UNKNOWN) | |
291 | break; | |
292 | } else if (nlh->nlmsg_type == NLMSG_ERROR) { | |
996c9314 LB |
293 | struct nlmsgerr *err = |
294 | (struct nlmsgerr | |
295 | *)((char *)nlh | |
296 | + NETLINK_ALIGN(sizeof( | |
297 | struct | |
298 | nlmsghdr))); | |
05895ad0 PG |
299 | if (err->error < 0) |
300 | errno = -err->error; | |
301 | else | |
302 | errno = err->error; | |
303 | break; | |
304 | } | |
305 | len = len - NETLINK_ALIGN(nlh->nlmsg_len); | |
996c9314 LB |
306 | nlh = (struct nlmsghdr *)((char *)nlh |
307 | + NETLINK_ALIGN( | |
308 | nlh->nlmsg_len)); | |
05895ad0 PG |
309 | } while (len != 0 && return_nsid != NS_UNKNOWN && ret == 0); |
310 | } | |
311 | ||
312 | close(fd); | |
313 | close(sock); | |
314 | return return_nsid; | |
315 | } | |
316 | ||
317 | #else | |
318 | ns_id_t zebra_ns_id_get(const char *netnspath) | |
319 | { | |
320 | return zebra_ns_id_get_fallback(netnspath); | |
321 | } | |
322 | #endif /* ! defined(HAVE_NETLINK) */ | |
ec31f30d PG |
323 | |
324 | #ifdef HAVE_NETNS | |
325 | static void zebra_ns_create_netns_directory(void) | |
326 | { | |
327 | /* check that /var/run/netns is created */ | |
328 | /* S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH */ | |
329 | if (mkdir(NS_RUN_DIR, 0755)) { | |
330 | if (errno != EEXIST) { | |
331 | zlog_warn("NS check: failed to access %s", NS_RUN_DIR); | |
332 | return; | |
333 | } | |
334 | } | |
335 | } | |
336 | #endif | |
337 | ||
338 | ns_id_t zebra_ns_id_get_default(void) | |
339 | { | |
340 | #ifdef HAVE_NETNS | |
341 | int fd; | |
342 | #endif /* !HAVE_NETNS */ | |
343 | ||
344 | #ifdef HAVE_NETNS | |
345 | if (vrf_is_backend_netns()) | |
346 | zebra_ns_create_netns_directory(); | |
347 | fd = open(NS_DEFAULT_NAME, O_RDONLY); | |
348 | ||
349 | if (fd == -1) | |
350 | return NS_DEFAULT_INTERNAL; | |
351 | if (!vrf_is_backend_netns()) | |
352 | return NS_DEFAULT_INTERNAL; | |
353 | close(fd); | |
354 | return zebra_ns_id_get((char *)NS_DEFAULT_NAME); | |
996c9314 | 355 | #else /* HAVE_NETNS */ |
ec31f30d PG |
356 | return NS_DEFAULT_INTERNAL; |
357 | #endif /* !HAVE_NETNS */ | |
358 | } |