Commit | Line | Data |
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2fe58dfd SE |
1 | /* UDP send/receive module for secnet */ |
2 | ||
3 | /* This module enables sites to communicate by sending UDP | |
4 | * packets. When an instance of the module is created we can | |
5 | * optionally bind to a particular local IP address (not implemented | |
6 | * yet). | |
7 | * | |
2fe58dfd SE |
8 | * Packets are offered to registered receivers in turn. Once one |
9 | * accepts it, it isn't offered to any more. */ | |
10 | ||
8689b3a9 | 11 | #include "secnet.h" |
2fe58dfd SE |
12 | #include <stdio.h> |
13 | #include <unistd.h> | |
14 | #include <fcntl.h> | |
15 | #include <string.h> | |
16 | #include <errno.h> | |
2fe58dfd | 17 | #include <sys/socket.h> |
b2a56f7c | 18 | #include <sys/wait.h> |
5edf478f IJ |
19 | #include <netinet/in.h> |
20 | #include <arpa/inet.h> | |
2fe58dfd | 21 | #include "util.h" |
dd9209d1 | 22 | #include "magic.h" |
794f2398 | 23 | #include "unaligned.h" |
ff05a229 | 24 | #include "ipaddr.h" |
136740e6 | 25 | #include "magic.h" |
54d5ef00 | 26 | #include "comm-common.h" |
2fe58dfd SE |
27 | |
28 | static beforepoll_fn udp_beforepoll; | |
29 | static afterpoll_fn udp_afterpoll; | |
2fe58dfd SE |
30 | static comm_sendmsg_fn udp_sendmsg; |
31 | ||
2fe58dfd | 32 | struct udp { |
763e458f IJ |
33 | struct udpcommon uc; |
34 | struct udpsocks socks; | |
2fe58dfd SE |
35 | }; |
36 | ||
08b62a6c IJ |
37 | /* |
38 | * Re comm_addr.ix: This field allows us to note in the comm_addr | |
39 | * which socket an incoming packet was received on. This is required | |
40 | * for conveniently logging the actual source of a packet. But the ix | |
41 | * does not formally form part of the address: it is not used when | |
42 | * sending, nor when comparing two comm_addrs. | |
43 | * | |
44 | * The special value -1 means that the comm_addr was constructed by | |
45 | * another module in secnet (eg the resolver), rather than being a | |
46 | * description of the source of an incoming packet. | |
47 | */ | |
48 | ||
54d5ef00 IJ |
49 | static const char *udp_addr_to_string(void *commst, const struct comm_addr *ca) |
50 | { | |
5edf478f | 51 | struct udp *st=commst; |
763e458f | 52 | struct udpsocks *socks=&st->socks; |
5edf478f | 53 | static char sbuf[100]; |
08b62a6c | 54 | int ix=ca->ix>=0 ? ca->ix : 0; |
5edf478f | 55 | |
7d31df0e | 56 | assert(ix>=0 && ix<socks->n_socks); |
08b62a6c | 57 | snprintf(sbuf, sizeof(sbuf), "udp:%s%s-%s", |
7d31df0e | 58 | iaddr_to_string(&socks->socks[ix].addr), |
08b62a6c IJ |
59 | ca->ix<0 ? "&" : "", |
60 | iaddr_to_string(&ca->ia)); | |
5edf478f IJ |
61 | return sbuf; |
62 | } | |
63 | ||
763e458f IJ |
64 | int udp_socks_beforepoll(struct udpsocks *socks, |
65 | struct pollfd *fds, int *nfds_io, | |
66 | int *timeout_io) | |
2fe58dfd | 67 | { |
08b62a6c | 68 | int i; |
7d31df0e IJ |
69 | BEFOREPOLL_WANT_FDS(socks->n_socks); |
70 | for (i=0; i<socks->n_socks; i++) { | |
71 | fds[i].fd=socks->socks[i].fd; | |
08b62a6c IJ |
72 | fds[i].events=POLLIN; |
73 | } | |
2fe58dfd SE |
74 | return 0; |
75 | } | |
76 | ||
763e458f IJ |
77 | static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io, |
78 | int *timeout_io) | |
2fe58dfd SE |
79 | { |
80 | struct udp *st=state; | |
763e458f IJ |
81 | return udp_socks_beforepoll(&st->socks,fds,nfds_io,timeout_io); |
82 | } | |
83 | ||
84 | void udp_socks_afterpoll(struct udpcommon *uc, struct udpsocks *socks, | |
85 | struct pollfd *fds, int nfds) | |
86 | { | |
a32d56fb | 87 | union iaddr from; |
b1a0f651 | 88 | socklen_t fromlen; |
2fe58dfd SE |
89 | bool_t done; |
90 | int rv; | |
08b62a6c | 91 | int i; |
2fe58dfd | 92 | |
763e458f IJ |
93 | struct commcommon *cc=&uc->cc; |
94 | ||
95 | for (i=0; i<socks->n_socks; i++) { | |
08b62a6c IJ |
96 | if (i>=nfds) continue; |
97 | if (!(fds[i].revents & POLLIN)) continue; | |
7d31df0e IJ |
98 | assert(fds[i].fd == socks->socks[i].fd); |
99 | int fd=socks->socks[i].fd; | |
2fe58dfd SE |
100 | do { |
101 | fromlen=sizeof(from); | |
7d31df0e IJ |
102 | BUF_ASSERT_FREE(cc->rbuf); |
103 | BUF_ALLOC(cc->rbuf,"udp_afterpoll"); | |
104 | buffer_init(cc->rbuf,calculate_max_start_pad()); | |
105 | rv=recvfrom(fd, cc->rbuf->start, | |
106 | buf_remaining_space(cc->rbuf), | |
a32d56fb | 107 | 0, &from.sa, &fromlen); |
2fe58dfd | 108 | if (rv>0) { |
7d31df0e IJ |
109 | cc->rbuf->size=rv; |
110 | if (uc->use_proxy) { | |
ff05a229 SE |
111 | /* Check that the packet came from our poxy server; |
112 | we shouldn't be contacted directly by anybody else | |
113 | (since they can trivially forge source addresses) */ | |
7d31df0e | 114 | if (!iaddr_equal(&from,&uc->proxy)) { |
ff05a229 SE |
115 | Message(M_INFO,"udp: received packet that's not " |
116 | "from the proxy\n"); | |
7d31df0e | 117 | BUF_FREE(cc->rbuf); |
ff05a229 SE |
118 | continue; |
119 | } | |
a32d56fb IJ |
120 | /* proxy protocol supports ipv4 transport only */ |
121 | from.sa.sa_family=AF_INET; | |
c1ddd026 | 122 | BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_addr,4); |
7d31df0e | 123 | buf_unprepend(cc->rbuf,2); |
c1ddd026 | 124 | BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_port,2); |
ff05a229 | 125 | } |
8534d602 | 126 | struct comm_addr ca; |
7d31df0e | 127 | ca.comm=&cc->ops; |
a32d56fb | 128 | ca.ia=from; |
08b62a6c | 129 | ca.ix=i; |
54d5ef00 | 130 | done=comm_notify(&cc->notify, cc->rbuf, &ca); |
2fe58dfd | 131 | if (!done) { |
bf28fc73 | 132 | uint32_t msgtype; |
7d31df0e IJ |
133 | if (cc->rbuf->size>12 /* prevents traffic amplification */ |
134 | && ((msgtype=get_uint32(cc->rbuf->start+8)) | |
bf28fc73 IJ |
135 | != LABEL_NAK)) { |
136 | uint32_t source,dest; | |
137 | /* Manufacture and send NAK packet */ | |
7d31df0e IJ |
138 | source=get_uint32(cc->rbuf->start); /* Us */ |
139 | dest=get_uint32(cc->rbuf->start+4); /* Them */ | |
140 | send_nak(&ca,source,dest,msgtype,cc->rbuf,"unwanted"); | |
bf28fc73 | 141 | } |
7d31df0e | 142 | BUF_FREE(cc->rbuf); |
2fe58dfd | 143 | } |
7d31df0e | 144 | BUF_ASSERT_FREE(cc->rbuf); |
2fe58dfd | 145 | } else { |
7d31df0e | 146 | BUF_FREE(cc->rbuf); |
2fe58dfd SE |
147 | } |
148 | } while (rv>=0); | |
149 | } | |
150 | } | |
151 | ||
763e458f IJ |
152 | static void udp_afterpoll(void *state, struct pollfd *fds, int nfds) |
153 | { | |
154 | struct udp *st=state; | |
155 | return udp_socks_afterpoll(&st->uc,&st->socks,fds,nfds); | |
156 | } | |
157 | ||
2fe58dfd | 158 | static bool_t udp_sendmsg(void *commst, struct buffer_if *buf, |
a15faeb2 | 159 | const struct comm_addr *dest) |
2fe58dfd SE |
160 | { |
161 | struct udp *st=commst; | |
763e458f IJ |
162 | struct udpcommon *uc=&st->uc; |
163 | struct udpsocks *socks=&st->socks; | |
ff05a229 | 164 | uint8_t *sa; |
2fe58dfd | 165 | |
7d31df0e | 166 | if (uc->use_proxy) { |
3abd18e8 | 167 | sa=buf_prepend(buf,8); |
a32d56fb IJ |
168 | if (dest->ia.sa.sa_family != AF_INET) { |
169 | Message(M_INFO, | |
170 | "udp: proxy means dropping outgoing non-IPv4 packet to %s\n", | |
171 | iaddr_to_string(&dest->ia)); | |
172 | return False; | |
173 | } | |
174 | memcpy(sa,&dest->ia.sin.sin_addr,4); | |
ff05a229 | 175 | memset(sa+4,0,4); |
a32d56fb | 176 | memcpy(sa+6,&dest->ia.sin.sin_port,2); |
7d31df0e IJ |
177 | sendto(socks->socks[0].fd,sa,buf->size+8,0,&uc->proxy.sa, |
178 | iaddr_socklen(&uc->proxy)); | |
3abd18e8 | 179 | buf_unprepend(buf,8); |
ff05a229 | 180 | } else { |
08b62a6c IJ |
181 | int i,r; |
182 | bool_t allunsupported=True; | |
7d31df0e IJ |
183 | for (i=0; i<socks->n_socks; i++) { |
184 | if (dest->ia.sa.sa_family != socks->socks[i].addr.sa.sa_family) | |
08b62a6c IJ |
185 | /* no point even trying */ |
186 | continue; | |
7d31df0e | 187 | r=sendto(socks->socks[i].fd, buf->start, buf->size, 0, |
08b62a6c IJ |
188 | &dest->ia.sa, iaddr_socklen(&dest->ia)); |
189 | if (r>=0) return True; | |
190 | if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH)) | |
191 | /* who knows what that error means? */ | |
192 | allunsupported=False; | |
193 | } | |
194 | return !allunsupported; /* see doc for comm_sendmsg_fn in secnet.h */ | |
ff05a229 | 195 | } |
2fe58dfd SE |
196 | |
197 | return True; | |
198 | } | |
199 | ||
08b62a6c | 200 | static void udp_make_socket(struct udp *st, struct udpsock *us) |
baa06aeb | 201 | { |
f164f167 | 202 | const union iaddr *addr=&us->addr; |
763e458f IJ |
203 | struct udpcommon *uc=&st->uc; |
204 | struct commcommon *cc=&uc->cc; | |
205 | ||
08b62a6c | 206 | us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP); |
f164f167 | 207 | if (us->fd<0) { |
7d31df0e | 208 | fatal_perror("udp (%s:%d): socket",cc->loc.file,cc->loc.line); |
baa06aeb | 209 | } |
f164f167 | 210 | if (fcntl(us->fd, F_SETFL, fcntl(us->fd, F_GETFL)|O_NONBLOCK)==-1) { |
baa06aeb | 211 | fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)", |
7d31df0e | 212 | cc->loc.file,cc->loc.line); |
baa06aeb | 213 | } |
f164f167 | 214 | setcloexec(us->fd); |
08b62a6c IJ |
215 | #ifdef CONFIG_IPV6 |
216 | if (addr->sa.sa_family==AF_INET6) { | |
217 | int r; | |
218 | int optval=1; | |
219 | socklen_t optlen=sizeof(optval); | |
220 | r=setsockopt(us->fd,IPPROTO_IPV6,IPV6_V6ONLY,&optval,optlen); | |
221 | if (r) fatal_perror("udp (%s:%d): setsockopt(,IPV6_V6ONLY,&1,)", | |
7d31df0e | 222 | cc->loc.file,cc->loc.line); |
08b62a6c IJ |
223 | } |
224 | #endif | |
baa06aeb | 225 | |
7d31df0e | 226 | if (uc->authbind) { |
b2a56f7c SE |
227 | pid_t c; |
228 | int status; | |
229 | ||
230 | /* XXX this fork() and waitpid() business needs to be hidden | |
231 | in some system-specific library functions. */ | |
232 | c=fork(); | |
233 | if (c==-1) { | |
234 | fatal_perror("udp_phase_hook: fork() for authbind"); | |
235 | } | |
236 | if (c==0) { | |
3ff31eda IJ |
237 | char *argv[5], addrstr[33], portstr[5]; |
238 | const char *addrfam; | |
239 | int port; | |
f164f167 | 240 | switch (addr->sa.sa_family) { |
a32d56fb | 241 | case AF_INET: |
f164f167 | 242 | sprintf(addrstr,"%08lX",(long)addr->sin.sin_addr.s_addr); |
3ff31eda IJ |
243 | port=addr->sin.sin_port; |
244 | addrfam=NULL; | |
a32d56fb | 245 | break; |
3ff31eda IJ |
246 | #ifdef CONFIG_IPV6 |
247 | case AF_INET6: { | |
248 | int i; | |
249 | for (i=0; i<16; i++) | |
250 | sprintf(addrstr+i*2,"%02X",addr->sin6.sin6_addr.s6_addr[i]); | |
251 | port=addr->sin6.sin6_port; | |
252 | addrfam="6"; | |
253 | break; | |
254 | } | |
255 | #endif /*CONFIG_IPV6*/ | |
a32d56fb IJ |
256 | default: |
257 | fatal("udp (%s:%d): unsupported address family for authbind", | |
7d31df0e | 258 | cc->loc.file,cc->loc.line); |
a32d56fb | 259 | } |
3ff31eda | 260 | sprintf(portstr,"%04X",port); |
7d31df0e | 261 | argv[0]=uc->authbind; |
3b83c932 SE |
262 | argv[1]=addrstr; |
263 | argv[2]=portstr; | |
3ff31eda IJ |
264 | argv[3]=(char*)addrfam; |
265 | argv[4]=NULL; | |
f164f167 | 266 | dup2(us->fd,0); |
7d31df0e | 267 | execvp(uc->authbind,argv); |
3b83c932 | 268 | _exit(255); |
b2a56f7c | 269 | } |
3b83c932 SE |
270 | while (waitpid(c,&status,0)==-1) { |
271 | if (errno==EINTR) continue; | |
7d31df0e | 272 | fatal_perror("udp (%s:%d): authbind",cc->loc.file,cc->loc.line); |
b2a56f7c | 273 | } |
3b83c932 | 274 | if (WIFSIGNALED(status)) { |
7d31df0e IJ |
275 | fatal("udp (%s:%d): authbind died on signal %d",cc->loc.file, |
276 | cc->loc.line, WTERMSIG(status)); | |
3b83c932 SE |
277 | } |
278 | if (WIFEXITED(status) && WEXITSTATUS(status)!=0) { | |
7d31df0e IJ |
279 | fatal("udp (%s:%d): authbind died with status %d",cc->loc.file, |
280 | cc->loc.line, WEXITSTATUS(status)); | |
3b83c932 | 281 | } |
b2a56f7c | 282 | } else { |
08b62a6c | 283 | if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0) { |
7d31df0e | 284 | fatal_perror("udp (%s:%d): bind",cc->loc.file,cc->loc.line); |
b2a56f7c | 285 | } |
baa06aeb | 286 | } |
f164f167 | 287 | } |
baa06aeb | 288 | |
f164f167 IJ |
289 | static void udp_phase_hook(void *sst, uint32_t new_phase) |
290 | { | |
291 | struct udp *st=sst; | |
763e458f | 292 | struct udpsocks *socks=&st->socks; |
08b62a6c | 293 | int i; |
7d31df0e IJ |
294 | for (i=0; i<socks->n_socks; i++) |
295 | udp_make_socket(st,&socks->socks[i]); | |
08b62a6c | 296 | |
32fc582f | 297 | register_for_poll(st,udp_beforepoll,udp_afterpoll,"udp"); |
baa06aeb SE |
298 | } |
299 | ||
2fe58dfd SE |
300 | static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context, |
301 | list_t *args) | |
302 | { | |
303 | struct udp *st; | |
08b62a6c | 304 | list_t *caddrl; |
ff05a229 SE |
305 | list_t *l; |
306 | uint32_t a; | |
08b62a6c | 307 | int i; |
2fe58dfd | 308 | |
763e458f IJ |
309 | COMM_APPLY(st,&st->uc.cc,udp_,"udp",loc); |
310 | COMM_APPLY_STANDARD(st,&st->uc.cc,"udp",args); | |
311 | UDP_APPLY_STANDARD(st,&st->uc,"udp"); | |
2fe58dfd | 312 | |
763e458f IJ |
313 | struct udpcommon *uc=&st->uc; |
314 | struct udpsocks *socks=&st->socks; | |
315 | struct commcommon *cc=&uc->cc; | |
08b62a6c IJ |
316 | |
317 | union iaddr defaultaddrs[] = { | |
318 | #ifdef CONFIG_IPV6 | |
319 | { .sin6 = { .sin6_family=AF_INET6, | |
763e458f | 320 | .sin6_port=htons(uc->port), |
08b62a6c IJ |
321 | .sin6_addr=IN6ADDR_ANY_INIT } }, |
322 | #endif | |
323 | { .sin = { .sin_family=AF_INET, | |
763e458f | 324 | .sin_port=htons(uc->port), |
08b62a6c IJ |
325 | .sin_addr= { .s_addr=INADDR_ANY } } } |
326 | }; | |
327 | ||
328 | caddrl=dict_lookup(d,"address"); | |
7d31df0e IJ |
329 | socks->n_socks=caddrl ? list_length(caddrl) : (int)ARRAY_SIZE(defaultaddrs); |
330 | if (socks->n_socks<=0 || socks->n_socks>UDP_MAX_SOCKETS) | |
331 | cfgfatal(cc->loc,"udp","`address' must be 1..%d addresses", | |
332 | UDP_MAX_SOCKETS); | |
08b62a6c | 333 | |
7d31df0e IJ |
334 | for (i=0; i<socks->n_socks; i++) { |
335 | struct udpsock *us=&socks->socks[i]; | |
08b62a6c IJ |
336 | if (!list_length(caddrl)) { |
337 | us->addr=defaultaddrs[i]; | |
338 | } else { | |
763e458f | 339 | string_item_to_iaddr(list_elem(caddrl,i),uc->port,&us->addr,"udp"); |
08b62a6c IJ |
340 | } |
341 | us->fd=-1; | |
342 | } | |
343 | ||
ff05a229 SE |
344 | l=dict_lookup(d,"proxy"); |
345 | if (l) { | |
7d31df0e IJ |
346 | uc->use_proxy=True; |
347 | uc->proxy.sa.sa_family=AF_INET; | |
c649eafe IJ |
348 | item=list_elem(l,0); |
349 | if (!item || item->type!=t_string) { | |
7d31df0e | 350 | cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n"); |
ff05a229 | 351 | } |
c649eafe | 352 | a=string_item_to_ipaddr(item,"proxy"); |
7d31df0e | 353 | uc->proxy.sin.sin_addr.s_addr=htonl(a); |
c649eafe IJ |
354 | item=list_elem(l,1); |
355 | if (!item || item->type!=t_number) { | |
7d31df0e | 356 | cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n"); |
ff05a229 | 357 | } |
7d31df0e | 358 | uc->proxy.sin.sin_port=htons(item->data.number); |
ff05a229 | 359 | } |
2fe58dfd | 360 | |
7d31df0e | 361 | update_max_start_pad(&comm_max_start_pad, uc->use_proxy ? 8 : 0); |
3abd18e8 | 362 | |
baa06aeb | 363 | add_hook(PHASE_GETRESOURCES,udp_phase_hook,st); |
2fe58dfd | 364 | |
7d31df0e | 365 | return new_closure(&cc->cl); |
2fe58dfd SE |
366 | } |
367 | ||
2fe58dfd SE |
368 | void udp_module(dict_t *dict) |
369 | { | |
370 | add_closure(dict,"udp",udp_apply); | |
371 | } |