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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 | 24 | #include "log.h" |
43e52561 | 25 | #include "lib_errors.h" |
05895ad0 | 26 | |
85a75f1e MS |
27 | #include "zebra/rib.h" |
28 | #include "zebra/zebra_dplane.h" | |
05895ad0 PG |
29 | #if defined(HAVE_NETLINK) |
30 | ||
31 | #include <linux/net_namespace.h> | |
32 | #include <linux/netlink.h> | |
33 | #include <linux/rtnetlink.h> | |
34 | ||
05895ad0 PG |
35 | #include "zebra_ns.h" |
36 | #include "kernel_netlink.h" | |
37 | #endif /* defined(HAVE_NETLINK) */ | |
38 | ||
43e52561 QY |
39 | #include "zebra/zebra_netns_id.h" |
40 | #include "zebra/zebra_errors.h" | |
05895ad0 | 41 | |
ec31f30d PG |
42 | /* default NS ID value used when VRF backend is not NETNS */ |
43 | #define NS_DEFAULT_INTERNAL 0 | |
44 | ||
05895ad0 PG |
45 | /* in case NEWNSID not available, the NSID will be locally obtained |
46 | */ | |
47 | #define NS_BASE_NSID 0 | |
48 | ||
49 | #if defined(HAVE_NETLINK) | |
50 | ||
51 | #define NETLINK_SOCKET_BUFFER_SIZE 512 | |
52 | #define NETLINK_ALIGNTO 4 | |
996c9314 LB |
53 | #define NETLINK_ALIGN(len) \ |
54 | (((len) + NETLINK_ALIGNTO - 1) & ~(NETLINK_ALIGNTO - 1)) | |
05895ad0 PG |
55 | #define NETLINK_NLATTR_LEN(_a, _b) (unsigned int)((char *)_a - (char *)_b) |
56 | ||
57 | #endif /* defined(HAVE_NETLINK) */ | |
58 | ||
59 | static ns_id_t zebra_ns_id_get_fallback(const char *netnspath) | |
60 | { | |
61 | static int zebra_ns_id_local; | |
62 | ||
63 | return zebra_ns_id_local++; | |
64 | } | |
65 | ||
66 | #if defined(HAVE_NETLINK) | |
67 | ||
68 | static struct nlmsghdr *initiate_nlh(char *buf, unsigned int *seq, int type) | |
69 | { | |
70 | struct nlmsghdr *nlh; | |
71 | ||
72 | nlh = (struct nlmsghdr *)buf; | |
73 | nlh->nlmsg_len = NETLINK_ALIGN(sizeof(struct nlmsghdr)); | |
74 | ||
75 | nlh->nlmsg_type = type; | |
76 | nlh->nlmsg_flags = NLM_F_REQUEST; | |
77 | if (type == RTM_NEWNSID) | |
78 | nlh->nlmsg_flags |= NLM_F_ACK; | |
79 | nlh->nlmsg_seq = *seq = time(NULL); | |
80 | return nlh; | |
81 | } | |
82 | ||
996c9314 LB |
83 | static int send_receive(int sock, struct nlmsghdr *nlh, unsigned int seq, |
84 | char *buf) | |
05895ad0 PG |
85 | { |
86 | int ret; | |
996c9314 | 87 | static const struct sockaddr_nl snl = {.nl_family = AF_NETLINK}; |
05895ad0 PG |
88 | |
89 | ret = sendto(sock, (const void *)nlh, (size_t)nlh->nlmsg_len, 0, | |
996c9314 | 90 | (struct sockaddr *)&snl, (socklen_t)sizeof(snl)); |
05895ad0 | 91 | if (ret < 0) { |
450971aa | 92 | flog_err_sys(EC_LIB_SOCKET, "netlink( %u) sendmsg() error: %s", |
09c866e3 | 93 | sock, safe_strerror(errno)); |
05895ad0 PG |
94 | return -1; |
95 | } | |
96 | ||
97 | /* reception */ | |
98 | struct sockaddr_nl addr; | |
99 | struct iovec iov = { | |
996c9314 | 100 | .iov_base = buf, .iov_len = NETLINK_SOCKET_BUFFER_SIZE, |
05895ad0 PG |
101 | }; |
102 | struct msghdr msg = { | |
996c9314 LB |
103 | .msg_name = &addr, |
104 | .msg_namelen = sizeof(struct sockaddr_nl), | |
105 | .msg_iov = &iov, | |
106 | .msg_iovlen = 1, | |
107 | .msg_control = NULL, | |
05895ad0 | 108 | .msg_controllen = 0, |
996c9314 | 109 | .msg_flags = 0, |
05895ad0 PG |
110 | }; |
111 | ret = recvmsg(sock, &msg, 0); | |
112 | if (ret < 0) { | |
450971aa | 113 | flog_err_sys(EC_LIB_SOCKET, |
09c866e3 QY |
114 | "netlink recvmsg: error %d (errno %u)", ret, |
115 | errno); | |
05895ad0 PG |
116 | return -1; |
117 | } | |
118 | if (msg.msg_flags & MSG_TRUNC) { | |
e914ccbe | 119 | flog_err(EC_ZEBRA_NETLINK_LENGTH_ERROR, |
1c50c1c0 | 120 | "netlink recvmsg : error message truncated"); |
05895ad0 PG |
121 | return -1; |
122 | } | |
123 | /* nlh already points to buf */ | |
124 | if (nlh->nlmsg_seq != seq) { | |
af4c2728 | 125 | flog_err( |
e914ccbe | 126 | EC_ZEBRA_NETLINK_BAD_SEQUENCE, |
996c9314 LB |
127 | "netlink recvmsg: bad sequence number %x (expected %x)", |
128 | seq, nlh->nlmsg_seq); | |
05895ad0 PG |
129 | return -1; |
130 | } | |
131 | return ret; | |
132 | } | |
133 | ||
134 | /* extract on a valid nlmsg the nsid | |
135 | * valid nlmsghdr - not a nlmsgerr | |
136 | */ | |
137 | static ns_id_t extract_nsid(struct nlmsghdr *nlh, char *buf) | |
138 | { | |
139 | ns_id_t ns_id = NS_UNKNOWN; | |
996c9314 LB |
140 | int offset = NETLINK_ALIGN(sizeof(struct nlmsghdr)) |
141 | + NETLINK_ALIGN(sizeof(struct rtgenmsg)); | |
05895ad0 PG |
142 | int curr_length = offset; |
143 | void *tail = (void *)((char *)nlh + NETLINK_ALIGN(nlh->nlmsg_len)); | |
144 | struct nlattr *attr; | |
145 | ||
146 | for (attr = (struct nlattr *)((char *)buf + offset); | |
996c9314 LB |
147 | NETLINK_NLATTR_LEN(tail, attr) >= sizeof(struct nlattr) |
148 | && attr->nla_len >= sizeof(struct nlattr) | |
149 | && attr->nla_len <= NETLINK_NLATTR_LEN(tail, attr); | |
05895ad0 PG |
150 | attr += NETLINK_ALIGN(attr->nla_len)) { |
151 | curr_length += attr->nla_len; | |
152 | if ((attr->nla_type & NLA_TYPE_MASK) == NETNSA_NSID) { | |
d7c0a89a | 153 | uint32_t *ptr = (uint32_t *)(attr); |
05895ad0 PG |
154 | |
155 | ns_id = ptr[1]; | |
156 | break; | |
157 | } | |
158 | } | |
159 | return ns_id; | |
160 | } | |
161 | ||
162 | ns_id_t zebra_ns_id_get(const char *netnspath) | |
163 | { | |
164 | int ns_id = -1; | |
165 | struct sockaddr_nl snl; | |
166 | int fd, sock, ret; | |
167 | unsigned int seq; | |
168 | ns_id_t return_nsid = NS_UNKNOWN; | |
169 | ||
170 | /* netns path check */ | |
171 | if (!netnspath) | |
172 | return NS_UNKNOWN; | |
173 | fd = open(netnspath, O_RDONLY); | |
174 | if (fd == -1) | |
175 | return NS_UNKNOWN; | |
176 | ||
177 | /* netlink socket */ | |
178 | sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); | |
179 | if (sock < 0) { | |
450971aa | 180 | flog_err_sys(EC_LIB_SOCKET, "netlink( %u) socket() error: %s", |
09c866e3 | 181 | sock, safe_strerror(errno)); |
af734bc7 | 182 | close(fd); |
05895ad0 PG |
183 | return NS_UNKNOWN; |
184 | } | |
185 | memset(&snl, 0, sizeof(snl)); | |
186 | snl.nl_family = AF_NETLINK; | |
187 | snl.nl_groups = RTNLGRP_NSID; | |
188 | snl.nl_pid = 0; /* AUTO PID */ | |
189 | ret = bind(sock, (struct sockaddr *)&snl, sizeof(snl)); | |
190 | if (ret < 0) { | |
450971aa | 191 | flog_err_sys(EC_LIB_SOCKET, |
09c866e3 QY |
192 | "netlink( %u) socket() bind error: %s", sock, |
193 | safe_strerror(errno)); | |
05895ad0 PG |
194 | close(sock); |
195 | close(fd); | |
196 | return NS_UNKNOWN; | |
197 | } | |
198 | ||
199 | /* message to send to netlink,and response : NEWNSID */ | |
200 | char buf[NETLINK_SOCKET_BUFFER_SIZE]; | |
201 | struct nlmsghdr *nlh; | |
202 | struct rtgenmsg *rt; | |
203 | int len; | |
204 | ||
205 | memset(buf, 0, NETLINK_SOCKET_BUFFER_SIZE); | |
206 | nlh = initiate_nlh(buf, &seq, RTM_NEWNSID); | |
207 | rt = (struct rtgenmsg *)(buf + nlh->nlmsg_len); | |
208 | nlh->nlmsg_len += NETLINK_ALIGN(sizeof(struct rtgenmsg)); | |
209 | rt->rtgen_family = AF_UNSPEC; | |
210 | ||
211 | addattr32(nlh, NETLINK_SOCKET_BUFFER_SIZE, NETNSA_FD, fd); | |
212 | addattr32(nlh, NETLINK_SOCKET_BUFFER_SIZE, NETNSA_NSID, ns_id); | |
213 | ||
214 | ret = send_receive(sock, nlh, seq, buf); | |
215 | if (ret < 0) { | |
216 | close(sock); | |
217 | close(fd); | |
218 | return NS_UNKNOWN; | |
219 | } | |
220 | nlh = (struct nlmsghdr *)buf; | |
221 | ||
222 | /* message to analyse : NEWNSID response */ | |
05895ad0 | 223 | ret = 0; |
b5891e15 A |
224 | if (nlh->nlmsg_type >= NLMSG_MIN_TYPE) { |
225 | return_nsid = extract_nsid(nlh, buf); | |
226 | } else { | |
227 | if (nlh->nlmsg_type == NLMSG_ERROR) { | |
228 | struct nlmsgerr *err = | |
229 | (struct nlmsgerr | |
230 | *)((char *)nlh | |
231 | + NETLINK_ALIGN( | |
232 | sizeof(struct nlmsghdr))); | |
233 | ||
234 | ret = -1; | |
235 | if (err->error < 0) | |
236 | errno = -err->error; | |
237 | else | |
238 | errno = err->error; | |
239 | if (errno == 0) { | |
240 | /* request NEWNSID was successfull | |
241 | * return EEXIST error to get GETNSID | |
05895ad0 | 242 | */ |
05895ad0 | 243 | errno = EEXIST; |
05895ad0 | 244 | } |
b5891e15 A |
245 | } else { |
246 | /* other errors ignored | |
247 | * attempt to get nsid | |
248 | */ | |
249 | ret = -1; | |
250 | errno = EEXIST; | |
05895ad0 | 251 | } |
b5891e15 | 252 | } |
05895ad0 PG |
253 | |
254 | if (ret <= 0) { | |
255 | if (errno != EEXIST && ret != 0) { | |
af4c2728 | 256 | flog_err( |
450971aa | 257 | EC_LIB_SOCKET, |
996c9314 LB |
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) { | |
9df414fe | 263 | zlog_debug("NEWNSID locally generated"); |
05895ad0 PG |
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)); | |
0cfbff74 | 309 | } while (len != 0 && ret == 0); |
05895ad0 PG |
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) { | |
e914ccbe | 331 | flog_warn(EC_ZEBRA_NAMESPACE_DIR_INACCESSIBLE, |
9df414fe | 332 | "NS check: failed to access %s", NS_RUN_DIR); |
ec31f30d PG |
333 | return; |
334 | } | |
335 | } | |
336 | } | |
337 | #endif | |
338 | ||
339 | ns_id_t zebra_ns_id_get_default(void) | |
340 | { | |
341 | #ifdef HAVE_NETNS | |
342 | int fd; | |
343 | #endif /* !HAVE_NETNS */ | |
344 | ||
345 | #ifdef HAVE_NETNS | |
346 | if (vrf_is_backend_netns()) | |
347 | zebra_ns_create_netns_directory(); | |
348 | fd = open(NS_DEFAULT_NAME, O_RDONLY); | |
349 | ||
350 | if (fd == -1) | |
351 | return NS_DEFAULT_INTERNAL; | |
4307629f DS |
352 | if (!vrf_is_backend_netns()) { |
353 | close(fd); | |
ec31f30d | 354 | return NS_DEFAULT_INTERNAL; |
4307629f | 355 | } |
ec31f30d PG |
356 | close(fd); |
357 | return zebra_ns_id_get((char *)NS_DEFAULT_NAME); | |
996c9314 | 358 | #else /* HAVE_NETNS */ |
ec31f30d PG |
359 | return NS_DEFAULT_INTERNAL; |
360 | #endif /* !HAVE_NETNS */ | |
361 | } |