Commit | Line | Data |
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ce5c098f IJ |
1 | /* polypath |
2 | * send/receive module for secnet | |
3 | * for multi-route setups */ | |
4 | ||
5 | #include "secnet.h" | |
6 | #include "util.h" | |
7 | #include "unaligned.h" | |
8 | #include "comm-common.h" | |
9 | ||
10 | #include <adns.h> | |
11 | #include <ctype.h> | |
12 | ||
13 | #ifdef CONFIG_IPV6 | |
14 | ||
15 | static comm_sendmsg_fn polypath_sendmsg; | |
16 | ||
17 | struct interf { | |
18 | char *name; /* from malloc */ | |
19 | struct udpsocks socks; | |
20 | bool_t experienced_xmit_noaf[MAX_AF+1]; | |
21 | LIST_ENTRY(interf) entry; | |
22 | }; | |
23 | ||
24 | struct polypath { | |
25 | struct udpcommon uc; | |
26 | int max_interfs; | |
27 | const char *const *ifname_pats; | |
28 | const char *const *monitor_command; | |
29 | bool_t permit_loopback; | |
30 | LIST_HEAD(,interf) interfs; | |
31 | struct buffer_if lbuf; | |
32 | int monitor_fd; | |
33 | pid_t monitor_pid; | |
34 | }; | |
35 | ||
36 | #define LG 0, st->uc.cc.cl.description, &st->uc.cc.loc | |
37 | ||
38 | static const char *const default_loopback_ifname_pats[] = { | |
39 | "!lo", 0 | |
40 | }; | |
41 | static const char *const default_ifname_pats[] = { | |
42 | "!tun*","!tap*","!sl*","!userv*", "*", 0 | |
43 | }; | |
44 | ||
45 | static const char *const default_monitor_command[] = { | |
46 | 0 | |
47 | }; | |
48 | ||
49 | static const char *polypath_addr_to_string(void *commst, | |
50 | const struct comm_addr *ca) | |
51 | { | |
52 | static char sbuf[100]; | |
53 | ||
54 | snprintf(sbuf, sizeof(sbuf), "polypath:%s", | |
55 | iaddr_to_string(&ca->ia)); | |
56 | return sbuf; | |
57 | } | |
58 | ||
59 | static bool_t ifname_search_pats(struct polypath *st, struct cloc loc, | |
60 | const char *ifname, bool_t *want_io, | |
61 | const char *const *pats) { | |
62 | /* Returns True iff we found a list entry, in which case *want_io | |
63 | * is set to the sense of that entry. Otherwise *want_io is set | |
64 | * to the sense of the last entry, or unchanged if there were no pats. */ | |
65 | if (!pats) | |
66 | return False; | |
67 | const char *const *pati; | |
68 | for (pati=pats; *pati; pati++) { | |
69 | const char *pat=*pati; | |
70 | if (*pat=='!') { *want_io=False; pat++; } | |
71 | else if (*pat=='+') { *want_io=True; pat++; } | |
72 | else if (*pat=='*' || isalnum((unsigned char)*pat)) { *want_io=True; } | |
73 | else cfgfatal(loc,"polypath","invalid interface name pattern `%s'",pat); | |
74 | int match=fnmatch(pat,ifname,0); | |
75 | if (match==0) return True; | |
76 | if (match!=FNM_NOMATCH) | |
77 | cfgfatal(loc,"polypath","fnmatch failed! (pattern `%s')",pat); | |
78 | } | |
79 | return False; | |
80 | } | |
81 | ||
82 | static bool_t ifname_wanted(struct polypath *st, struct cloc loc, | |
83 | const char *ifname) { | |
84 | bool_t want=False; /* pretend an empty cfg ends with !<doesn'tmatch> */ | |
85 | if (ifname_search_pats(st,loc,ifname,&want, st->ifname_pats)) | |
86 | return want; | |
87 | if (want) /* last pattern was positive, do not search default */ | |
88 | return False; | |
89 | if (!st->permit_loopback && | |
90 | ifname_search_pats(st,loc,ifname,&want, default_loopback_ifname_pats)) | |
91 | return want; | |
92 | if (ifname_search_pats(st,loc,ifname,&want, default_ifname_pats)) | |
93 | return want; | |
94 | abort(); | |
95 | } | |
96 | ||
97 | static int polypath_beforepoll(void *state, struct pollfd *fds, int *nfds_io, | |
98 | int *timeout_io) | |
99 | { | |
100 | struct polypath *st=state; | |
101 | BEFOREPOLL_WANT_FDS(1); | |
102 | fds[0].fd=st->monitor_fd; | |
103 | fds[0].events=POLLIN; | |
104 | return 0; | |
105 | } | |
106 | ||
107 | static void dump_ppml(struct polypath *st, const char *orgl) | |
108 | { | |
109 | #ifdef POLYPATH_DEBUG | |
110 | struct interf *interf; | |
111 | if (orgl) | |
112 | lg_perror(LG,M_DEBUG,0, "polypath monitor line `%s'",orgl); | |
113 | LIST_FOREACH(interf, &st->interfs, entry) { | |
114 | lg_perror(LG,M_DEBUG,0, " polypath interface `%s', nsocks=%d", | |
115 | interf->name, interf->socks.n_socks); | |
116 | int i; | |
117 | for (i=0; i<interf->socks.n_socks; i++) { | |
118 | struct udpsock *us=&interf->socks.socks[i]; | |
119 | lg_perror(LG,M_DEBUG,0, " polypath sock fd=%d addr=%s", | |
120 | us->fd, iaddr_to_string(&us->addr)); | |
121 | } | |
122 | } | |
123 | #endif | |
124 | } | |
125 | ||
126 | static void bad(struct polypath *st, char *l, char *undospace, | |
127 | const char *m, int ev) | |
128 | { | |
129 | if (undospace) | |
130 | *undospace=' '; | |
131 | lg_perror(LG,M_WARNING,ev, | |
132 | "error processing polypath state change: %s" | |
133 | " (while processing `%s')", | |
134 | m,l); | |
135 | } | |
136 | ||
137 | static inline bool_t matches32(uint32_t word, uint32_t prefix, int prefixlen) | |
138 | { | |
139 | assert(prefixlen>0); | |
140 | assert(prefixlen<=32); | |
141 | uint32_t mask = ~(((uint32_t)1 << (32-prefixlen)) - 1); | |
142 | assert(!(prefix & ~mask)); | |
143 | return (word & mask) == prefix; | |
144 | } | |
145 | ||
146 | static void polypath_process_monitor_line(struct polypath *st, char *orgl) | |
147 | { | |
148 | struct interf *interf=0; | |
149 | struct udpcommon *uc=&st->uc; | |
150 | char *undospace=0; | |
151 | char *l=orgl; | |
152 | struct udpsock *us=0; | |
153 | ||
154 | dump_ppml(st,orgl); | |
155 | ||
156 | #define BAD(m) do{ bad(st,orgl,undospace,m,0); goto out; }while(0) | |
157 | #define BADE(m,ev) do{ bad(st,orgl,undospace,m,ev); goto out; }while(0) | |
158 | ||
159 | bool_t add; | |
160 | int c=*l++; | |
161 | if (c=='+') add=True; | |
162 | else if (c=='-') add=False; | |
163 | else BAD("bad +/-"); | |
164 | ||
165 | int proto; | |
166 | c=*l++; | |
167 | if (c=='4') proto=AF_INET; | |
168 | else if (c=='6') proto=AF_INET6; | |
169 | else BAD("bad proto"); | |
170 | ||
171 | char *space=strchr(l,' '); | |
172 | if (!space) BAD("no first space"); | |
173 | const char *ifname=space+1; | |
174 | ||
175 | space=strchr(ifname,' '); | |
176 | if (!space) BAD("no second space"); | |
177 | const char *ifaddr=space+1; | |
178 | *space=0; | |
179 | undospace=space; | |
180 | ||
181 | union iaddr ia; | |
182 | FILLZERO(ia); | |
183 | socklen_t salen=sizeof(ia); | |
184 | int r=adns_text2addr(ifaddr,uc->port, adns_qf_addrlit_ipv4_quadonly, | |
185 | &ia.sa, &salen); | |
186 | assert(r!=ENOSPC); | |
187 | if (r) BADE("adns_text2addr",r); | |
188 | if (ia.sa.sa_family!=proto) BAD("address family mismatch"); | |
189 | ||
190 | #define DONT(m) do{ \ | |
191 | if (add) \ | |
192 | lg_perror(LG,M_INFO,0,"ignoring %s [%s]: %s",ifname,ifaddr,m); \ | |
193 | goto out; \ | |
194 | }while(0) | |
195 | ||
196 | if (!ifname_wanted(st,st->uc.cc.loc,ifname)) | |
197 | DONT("unwanted interface name"); | |
198 | ||
199 | switch (ia.sa.sa_family) { | |
200 | case AF_INET6: { | |
201 | const struct in6_addr *i6=&ia.sin6.sin6_addr; | |
202 | #define DONTKIND(X,m) \ | |
203 | if (IN6_IS_ADDR_##X(i6)) DONT("IPv6 address is " m) | |
204 | DONTKIND(UNSPECIFIED, "unspecified"); | |
205 | DONTKIND(MULTICAST , "multicast" ); | |
206 | DONTKIND(LINKLOCAL , "link local" ); | |
207 | DONTKIND(SITELOCAL , "site local" ); | |
208 | DONTKIND(V4MAPPED , "v4-mapped" ); | |
209 | if (!st->permit_loopback) | |
210 | DONTKIND(LOOPBACK , "loopback" ); | |
211 | #undef DONTKIND | |
212 | #define DONTMASK(w7x,w6x,prefixlen,m) \ | |
213 | if (matches32(get_uint32(i6->s6_addr), \ | |
214 | ((uint32_t)0x##w7x << 16) | (uint32_t)0x##w6x, \ | |
215 | prefixlen)) \ | |
216 | DONT("IPv6 address is " m) | |
217 | DONTMASK( 100, 0, 8, "Discard-Only (RFC6666)"); | |
218 | DONTMASK(2001, 0, 23, "in IETF protocol block (RFC2928)"); | |
219 | #undef DONTMASK | |
220 | break; | |
221 | } | |
222 | case AF_INET: { | |
223 | const uint32_t i4=htonl(ia.sin.sin_addr.s_addr); | |
224 | if (i4==INADDR_ANY) DONT("IPv4 address is any/unspecified"); | |
225 | if (i4==INADDR_BROADCAST) DONT("IPv4 address is all hosts broadcast"); | |
226 | #define DONTMASK(b3,b2,b1,b0,prefixlen,m) do{ \ | |
227 | const uint8_t prefixbytes[4] = { (b3),(b2),(b1),(b0) }; \ | |
228 | if (matches32(i4,get_uint32(prefixbytes),prefixlen)) \ | |
229 | DONT("IPv4 address is " m); \ | |
230 | }while(0) | |
231 | DONTMASK(169,254,0,0, 16, "link local"); | |
232 | DONTMASK(224, 0,0,0, 4, "multicast"); | |
233 | DONTMASK(192, 0,0,0, 24, "in IETF protocol block (RFC6890)"); | |
234 | DONTMASK(240, 0,0,0, 4, "in reserved addressing block (RFC1112)"); | |
235 | if (!st->permit_loopback) | |
236 | DONTMASK(127, 0,0,0, 8, "loopback"); | |
237 | #undef DONTMASK | |
238 | break; | |
239 | } | |
240 | default: | |
241 | abort(); | |
242 | } | |
243 | ||
244 | /* OK, process it */ | |
245 | int n_ifs=0; | |
246 | LIST_FOREACH(interf,&st->interfs,entry) { | |
247 | if (!strcmp(interf->name,ifname)) | |
248 | goto found_interf; | |
249 | n_ifs++; | |
250 | } | |
251 | /* not found */ | |
252 | if (n_ifs==st->max_interfs) BAD("too many interfaces"); | |
253 | interf=malloc(sizeof(*interf)); | |
254 | if (!interf) BADE("malloc for new interface",errno); | |
255 | interf->name=0; | |
256 | interf->socks.n_socks=0; | |
257 | FILLZERO(interf->experienced_xmit_noaf); | |
258 | LIST_INSERT_HEAD(&st->interfs,interf,entry); | |
259 | udp_socks_register(&st->uc,&interf->socks); | |
260 | interf->name=strdup(ifname); | |
261 | if (!interf->name) BADE("strdup interface name",errno); | |
262 | found_interf: | |
263 | ||
264 | if (add) { | |
265 | if (interf->socks.n_socks == UDP_MAX_SOCKETS) | |
266 | BAD("too many addresses on this interface"); | |
267 | struct udpsock *us=&interf->socks.socks[interf->socks.n_socks]; | |
268 | us->fd=-1; | |
269 | COPY_OBJ(us->addr,ia); | |
270 | bool_t ok=udp_make_socket(&st->uc,us,M_WARNING); | |
271 | if (!ok) BAD("unable to set up socket"); | |
272 | r=setsockopt(us->fd,SOL_SOCKET,SO_BINDTODEVICE, | |
273 | ifname,strlen(ifname)+1); | |
274 | if (r) BADE("setsockopt(,,SO_BINDTODEVICE,)",errno); | |
275 | interf->socks.n_socks++; | |
276 | us=0; /* do not destroy this socket during `out' */ | |
277 | lg_perror(LG,M_INFO,0,"using %s %s",ifname,ifaddr); | |
278 | } else { | |
279 | int i; | |
280 | for (i=0; i<interf->socks.n_socks; i++) | |
281 | if (!memcmp(&interf->socks.socks[i].addr,&ia,sizeof(ia))) | |
282 | goto address_remove_found; | |
283 | BAD("address to remove not found"); | |
284 | address_remove_found: | |
285 | lg_perror(LG,M_INFO,0,"removed %s %s",ifname,ifaddr); | |
286 | udp_destroy_socket(&st->uc,&interf->socks.socks[i]); | |
287 | interf->socks.socks[i]= | |
288 | interf->socks.socks[--interf->socks.n_socks]; | |
289 | } | |
290 | ||
291 | out: | |
292 | if (us) | |
293 | udp_destroy_socket(uc,us); | |
294 | if (interf && !interf->socks.n_socks) { | |
295 | udp_socks_deregister(&st->uc,&interf->socks); | |
296 | LIST_REMOVE(interf,entry); | |
297 | free(interf->name); | |
298 | free(interf); | |
299 | } | |
300 | ||
301 | dump_ppml(st,0); | |
302 | ||
303 | #undef BAD | |
304 | #undef BADE | |
305 | #undef DONT | |
306 | } | |
307 | ||
308 | static void polypath_afterpoll(void *state, struct pollfd *fds, int nfds) | |
309 | { | |
310 | struct polypath *st=state; | |
311 | enum async_linebuf_result alr; | |
312 | const char *emsg; | |
313 | int status; | |
314 | ||
315 | if (nfds<1) return; | |
316 | ||
317 | while ((alr=async_linebuf_read(fds,&st->lbuf,&emsg)) == async_linebuf_ok) | |
318 | polypath_process_monitor_line(st,st->lbuf.base); | |
319 | ||
320 | if (alr==async_linebuf_nothing) | |
321 | return; | |
322 | ||
323 | assert(st->monitor_pid); | |
324 | ||
325 | pid_t gotpid=waitpid(st->monitor_pid,&status,WNOHANG); | |
326 | if (gotpid==st->monitor_pid) { | |
327 | st->monitor_pid=0; | |
328 | lg_exitstatus(LG,M_FATAL,status,"interface monitor"); | |
329 | } else if (gotpid<0) | |
330 | lg_perror(LG,M_ERR,errno,"unable to reap interface monitor"); | |
331 | else | |
332 | assert(gotpid==0); | |
333 | ||
334 | if (alr==async_linebuf_eof) | |
335 | lg_perror(LG,M_FATAL,0,"unexpected EOF from interface monitor"); | |
336 | else | |
337 | lg_perror(LG,M_FATAL,0,"bad output from interface monitor: %s",emsg); | |
338 | ||
339 | assert(!"not reached"); | |
340 | } | |
341 | ||
342 | /* Actual udp packet sending work */ | |
343 | static bool_t polypath_sendmsg(void *commst, struct buffer_if *buf, | |
344 | const struct comm_addr *dest) | |
345 | { | |
346 | struct polypath *st=commst; | |
347 | struct interf *interf; | |
348 | bool_t allreasonable=True; | |
349 | int af=dest->ia.sa.sa_family; | |
350 | ||
351 | LIST_FOREACH(interf,&st->interfs,entry) { | |
352 | int i; | |
353 | bool_t attempted=False, reasonable=False; | |
354 | for (i=0; i<interf->socks.n_socks; i++) { | |
355 | struct udpsock *us=&interf->socks.socks[i]; | |
356 | if (af != us->addr.sa.sa_family) | |
357 | continue; | |
358 | attempted=True; | |
359 | int r=sendto(us->fd,buf->start,buf->size, | |
360 | 0,&dest->ia.sa,iaddr_socklen(&dest->ia)); | |
361 | udp_sock_experienced(0,&st->uc, interf->name,us, | |
362 | 1,af, r,errno); | |
363 | if (r>=0) { | |
364 | reasonable=True; | |
365 | break; | |
366 | } | |
367 | if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH)) | |
368 | reasonable=True; | |
369 | lg_perror(LG,M_DEBUG,errno,"%s [%s] xmit %"PRIu32" bytes to %s", | |
370 | interf->name,iaddr_to_string(&us->addr), | |
371 | buf->size,iaddr_to_string(&dest->ia)); | |
372 | } | |
373 | if (!attempted) | |
374 | if (!interf->experienced_xmit_noaf[af]++) | |
375 | lg_perror(LG,M_WARNING,0, | |
376 | "%s has no suitable address to transmit %s", | |
377 | interf->name, af_name(af)); | |
378 | allreasonable *= reasonable; | |
379 | } | |
380 | return allreasonable; | |
381 | } | |
382 | ||
383 | static void polypath_phase_startmonitor(void *sst, uint32_t newphase) | |
384 | { | |
385 | struct polypath *st=sst; | |
386 | int pfds[2]; | |
387 | ||
388 | assert(!st->monitor_pid); | |
389 | assert(st->monitor_fd<0); | |
390 | ||
391 | pipe_cloexec(pfds); | |
392 | ||
393 | pid_t pid=fork(); | |
394 | if (!pid) { | |
395 | afterfork(); | |
396 | dup2(pfds[1],1); | |
397 | execvp(st->monitor_command[0],(char**)st->monitor_command); | |
398 | fprintf(stderr,"secnet: cannot execute %s: %s\n", | |
399 | st->monitor_command[0], strerror(errno)); | |
400 | exit(-1); | |
401 | } | |
402 | if (pid<0) | |
403 | fatal_perror("%s: failed to fork for interface monitor", | |
404 | st->uc.cc.cl.description); | |
405 | ||
406 | close(pfds[1]); | |
407 | st->monitor_pid=pid; | |
408 | st->monitor_fd=pfds[0]; | |
409 | setnonblock(st->monitor_fd); | |
410 | ||
411 | register_for_poll(st,polypath_beforepoll,polypath_afterpoll,"polypath"); | |
412 | } | |
413 | ||
414 | static void polypath_phase_shutdown(void *sst, uint32_t newphase) | |
415 | { | |
416 | struct polypath *st=sst; | |
417 | if (st->monitor_pid) { | |
418 | assert(st->monitor_pid>0); | |
419 | kill(st->monitor_pid,SIGTERM); | |
420 | } | |
421 | } | |
422 | ||
423 | static list_t *polypath_apply(closure_t *self, struct cloc loc, | |
424 | dict_t *context, list_t *args) | |
425 | { | |
426 | struct polypath *st; | |
427 | ||
428 | COMM_APPLY(st,&st->uc.cc,polypath_,"polypath",loc); | |
429 | COMM_APPLY_STANDARD(st,&st->uc.cc,"polypath",args); | |
430 | UDP_APPLY_STANDARD(st,&st->uc,"polypath"); | |
431 | ||
432 | struct udpcommon *uc=&st->uc; | |
433 | struct commcommon *cc=&uc->cc; | |
434 | ||
435 | st->max_interfs=dict_read_number(d,"max-interfaces",False,"polypath",loc,3); | |
436 | ||
437 | st->ifname_pats=dict_read_string_array(d,"interfaces",False,"polypath", | |
438 | cc->loc,0); | |
439 | st->permit_loopback=0; /* ifname_wanted reads this */ | |
440 | ifname_wanted(st,st->uc.cc.loc," "); /* try to check each pattern */ | |
441 | ||
442 | st->monitor_command=dict_read_string_array(d,"monitor-command",False, | |
443 | "polypath",cc->loc, default_monitor_command); | |
444 | if (!st->monitor_command[0]) | |
445 | cfgfatal(loc,"polypath","no polypath interface monitor-command" | |
446 | " (polypath unsupported on this platform?)\n"); | |
447 | ||
448 | st->permit_loopback=dict_read_bool(d,"permit-loopback",False, | |
449 | "polypath",cc->loc,False); | |
450 | ||
451 | LIST_INIT(&st->interfs); | |
452 | buffer_new(&st->lbuf,ADNS_ADDR2TEXT_BUFLEN+100); | |
453 | BUF_ALLOC(&st->lbuf,"polypath lbuf"); | |
454 | ||
455 | st->monitor_fd=-1; | |
456 | st->monitor_pid=0; | |
457 | ||
458 | add_hook(PHASE_RUN, polypath_phase_startmonitor,st); | |
459 | add_hook(PHASE_SHUTDOWN, polypath_phase_shutdown, st); | |
460 | ||
461 | return new_closure(&cc->cl); | |
462 | } | |
463 | ||
464 | #endif /* CONFIG_IPV6 */ | |
465 | ||
466 | void polypath_module(dict_t *dict) | |
467 | { | |
468 | #ifdef CONFIG_IPV6 | |
469 | add_closure(dict,"polypath",polypath_apply); | |
470 | #endif /* CONFIG_IPV6 */ | |
471 | } |