Commit | Line | Data |
---|---|---|
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 | 27 | |
2fe58dfd SE |
28 | static comm_sendmsg_fn udp_sendmsg; |
29 | ||
2fe58dfd | 30 | struct udp { |
763e458f IJ |
31 | struct udpcommon uc; |
32 | struct udpsocks socks; | |
2fe58dfd SE |
33 | }; |
34 | ||
08b62a6c IJ |
35 | /* |
36 | * Re comm_addr.ix: This field allows us to note in the comm_addr | |
37 | * which socket an incoming packet was received on. This is required | |
38 | * for conveniently logging the actual source of a packet. But the ix | |
39 | * does not formally form part of the address: it is not used when | |
40 | * sending, nor when comparing two comm_addrs. | |
41 | * | |
42 | * The special value -1 means that the comm_addr was constructed by | |
43 | * another module in secnet (eg the resolver), rather than being a | |
44 | * description of the source of an incoming packet. | |
45 | */ | |
46 | ||
54d5ef00 IJ |
47 | static const char *udp_addr_to_string(void *commst, const struct comm_addr *ca) |
48 | { | |
5edf478f | 49 | struct udp *st=commst; |
763e458f | 50 | struct udpsocks *socks=&st->socks; |
5edf478f | 51 | static char sbuf[100]; |
08b62a6c | 52 | int ix=ca->ix>=0 ? ca->ix : 0; |
5edf478f | 53 | |
7d31df0e | 54 | assert(ix>=0 && ix<socks->n_socks); |
08b62a6c | 55 | snprintf(sbuf, sizeof(sbuf), "udp:%s%s-%s", |
7d31df0e | 56 | iaddr_to_string(&socks->socks[ix].addr), |
08b62a6c IJ |
57 | ca->ix<0 ? "&" : "", |
58 | iaddr_to_string(&ca->ia)); | |
5edf478f IJ |
59 | return sbuf; |
60 | } | |
61 | ||
f7af3192 IJ |
62 | static int udp_socks_beforepoll(void *state, struct pollfd *fds, int *nfds_io, |
63 | int *timeout_io) | |
2fe58dfd | 64 | { |
f7af3192 | 65 | struct udpsocks *socks=state; |
08b62a6c | 66 | int i; |
7d31df0e IJ |
67 | BEFOREPOLL_WANT_FDS(socks->n_socks); |
68 | for (i=0; i<socks->n_socks; i++) { | |
69 | fds[i].fd=socks->socks[i].fd; | |
08b62a6c IJ |
70 | fds[i].events=POLLIN; |
71 | } | |
2fe58dfd SE |
72 | return 0; |
73 | } | |
74 | ||
f7af3192 | 75 | static void udp_socks_afterpoll(void *state, struct pollfd *fds, int nfds) |
763e458f | 76 | { |
f7af3192 IJ |
77 | struct udpsocks *socks=state; |
78 | struct udpcommon *uc=socks->uc; | |
a32d56fb | 79 | union iaddr from; |
b1a0f651 | 80 | socklen_t fromlen; |
2fe58dfd SE |
81 | bool_t done; |
82 | int rv; | |
08b62a6c | 83 | int i; |
2fe58dfd | 84 | |
763e458f IJ |
85 | struct commcommon *cc=&uc->cc; |
86 | ||
87 | for (i=0; i<socks->n_socks; i++) { | |
08b62a6c IJ |
88 | if (i>=nfds) continue; |
89 | if (!(fds[i].revents & POLLIN)) continue; | |
7d31df0e IJ |
90 | assert(fds[i].fd == socks->socks[i].fd); |
91 | int fd=socks->socks[i].fd; | |
2fe58dfd SE |
92 | do { |
93 | fromlen=sizeof(from); | |
7d31df0e IJ |
94 | BUF_ASSERT_FREE(cc->rbuf); |
95 | BUF_ALLOC(cc->rbuf,"udp_afterpoll"); | |
96 | buffer_init(cc->rbuf,calculate_max_start_pad()); | |
97 | rv=recvfrom(fd, cc->rbuf->start, | |
98 | buf_remaining_space(cc->rbuf), | |
a32d56fb | 99 | 0, &from.sa, &fromlen); |
2fe58dfd | 100 | if (rv>0) { |
7d31df0e IJ |
101 | cc->rbuf->size=rv; |
102 | if (uc->use_proxy) { | |
ff05a229 SE |
103 | /* Check that the packet came from our poxy server; |
104 | we shouldn't be contacted directly by anybody else | |
105 | (since they can trivially forge source addresses) */ | |
7d31df0e | 106 | if (!iaddr_equal(&from,&uc->proxy)) { |
ff05a229 SE |
107 | Message(M_INFO,"udp: received packet that's not " |
108 | "from the proxy\n"); | |
7d31df0e | 109 | BUF_FREE(cc->rbuf); |
ff05a229 SE |
110 | continue; |
111 | } | |
a32d56fb IJ |
112 | /* proxy protocol supports ipv4 transport only */ |
113 | from.sa.sa_family=AF_INET; | |
c1ddd026 | 114 | BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_addr,4); |
7d31df0e | 115 | buf_unprepend(cc->rbuf,2); |
c1ddd026 | 116 | BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_port,2); |
ff05a229 | 117 | } |
8534d602 | 118 | struct comm_addr ca; |
7d31df0e | 119 | ca.comm=&cc->ops; |
a32d56fb | 120 | ca.ia=from; |
08b62a6c | 121 | ca.ix=i; |
54d5ef00 | 122 | done=comm_notify(&cc->notify, cc->rbuf, &ca); |
2fe58dfd | 123 | if (!done) { |
bf28fc73 | 124 | uint32_t msgtype; |
7d31df0e IJ |
125 | if (cc->rbuf->size>12 /* prevents traffic amplification */ |
126 | && ((msgtype=get_uint32(cc->rbuf->start+8)) | |
bf28fc73 IJ |
127 | != LABEL_NAK)) { |
128 | uint32_t source,dest; | |
129 | /* Manufacture and send NAK packet */ | |
7d31df0e IJ |
130 | source=get_uint32(cc->rbuf->start); /* Us */ |
131 | dest=get_uint32(cc->rbuf->start+4); /* Them */ | |
132 | send_nak(&ca,source,dest,msgtype,cc->rbuf,"unwanted"); | |
bf28fc73 | 133 | } |
7d31df0e | 134 | BUF_FREE(cc->rbuf); |
2fe58dfd | 135 | } |
7d31df0e | 136 | BUF_ASSERT_FREE(cc->rbuf); |
2fe58dfd | 137 | } else { |
7d31df0e | 138 | BUF_FREE(cc->rbuf); |
2fe58dfd SE |
139 | } |
140 | } while (rv>=0); | |
141 | } | |
142 | } | |
143 | ||
2fe58dfd | 144 | static bool_t udp_sendmsg(void *commst, struct buffer_if *buf, |
a15faeb2 | 145 | const struct comm_addr *dest) |
2fe58dfd SE |
146 | { |
147 | struct udp *st=commst; | |
763e458f IJ |
148 | struct udpcommon *uc=&st->uc; |
149 | struct udpsocks *socks=&st->socks; | |
ff05a229 | 150 | uint8_t *sa; |
2fe58dfd | 151 | |
7d31df0e | 152 | if (uc->use_proxy) { |
3abd18e8 | 153 | sa=buf_prepend(buf,8); |
a32d56fb IJ |
154 | if (dest->ia.sa.sa_family != AF_INET) { |
155 | Message(M_INFO, | |
156 | "udp: proxy means dropping outgoing non-IPv4 packet to %s\n", | |
157 | iaddr_to_string(&dest->ia)); | |
158 | return False; | |
159 | } | |
160 | memcpy(sa,&dest->ia.sin.sin_addr,4); | |
ff05a229 | 161 | memset(sa+4,0,4); |
a32d56fb | 162 | memcpy(sa+6,&dest->ia.sin.sin_port,2); |
7d31df0e IJ |
163 | sendto(socks->socks[0].fd,sa,buf->size+8,0,&uc->proxy.sa, |
164 | iaddr_socklen(&uc->proxy)); | |
3abd18e8 | 165 | buf_unprepend(buf,8); |
ff05a229 | 166 | } else { |
08b62a6c IJ |
167 | int i,r; |
168 | bool_t allunsupported=True; | |
7d31df0e IJ |
169 | for (i=0; i<socks->n_socks; i++) { |
170 | if (dest->ia.sa.sa_family != socks->socks[i].addr.sa.sa_family) | |
08b62a6c IJ |
171 | /* no point even trying */ |
172 | continue; | |
7d31df0e | 173 | r=sendto(socks->socks[i].fd, buf->start, buf->size, 0, |
08b62a6c IJ |
174 | &dest->ia.sa, iaddr_socklen(&dest->ia)); |
175 | if (r>=0) return True; | |
176 | if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH)) | |
177 | /* who knows what that error means? */ | |
178 | allunsupported=False; | |
179 | } | |
180 | return !allunsupported; /* see doc for comm_sendmsg_fn in secnet.h */ | |
ff05a229 | 181 | } |
2fe58dfd SE |
182 | |
183 | return True; | |
184 | } | |
185 | ||
53f4e666 IJ |
186 | bool_t udp_make_socket(struct udpcommon *uc, struct udpsock *us, |
187 | int failmsgclass) | |
baa06aeb | 188 | { |
f164f167 | 189 | const union iaddr *addr=&us->addr; |
763e458f | 190 | struct commcommon *cc=&uc->cc; |
53f4e666 IJ |
191 | us->fd=-1; |
192 | ||
193 | #define FAIL_LG 0, cc->cl.description, &cc->loc, failmsgclass | |
194 | #define FAIL(...) do{ \ | |
195 | lg_perror(FAIL_LG,errno,__VA_ARGS__); \ | |
196 | goto failed; \ | |
197 | }while(0) | |
763e458f | 198 | |
08b62a6c | 199 | us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP); |
53f4e666 IJ |
200 | if (us->fd<0) FAIL("socket"); |
201 | if (fcntl(us->fd, F_SETFL, fcntl(us->fd, F_GETFL)|O_NONBLOCK)==-1) | |
202 | FAIL("fcntl(set O_NONBLOCK)"); | |
f164f167 | 203 | setcloexec(us->fd); |
08b62a6c IJ |
204 | #ifdef CONFIG_IPV6 |
205 | if (addr->sa.sa_family==AF_INET6) { | |
206 | int r; | |
207 | int optval=1; | |
208 | socklen_t optlen=sizeof(optval); | |
209 | r=setsockopt(us->fd,IPPROTO_IPV6,IPV6_V6ONLY,&optval,optlen); | |
53f4e666 | 210 | if (r) FAIL("setsockopt(,IPV6_V6ONLY,&1,)"); |
08b62a6c IJ |
211 | } |
212 | #endif | |
baa06aeb | 213 | |
7d31df0e | 214 | if (uc->authbind) { |
b2a56f7c SE |
215 | pid_t c; |
216 | int status; | |
217 | ||
218 | /* XXX this fork() and waitpid() business needs to be hidden | |
219 | in some system-specific library functions. */ | |
220 | c=fork(); | |
53f4e666 IJ |
221 | if (c==-1) |
222 | FAIL("fork() for authbind"); | |
b2a56f7c | 223 | if (c==0) { |
3ff31eda IJ |
224 | char *argv[5], addrstr[33], portstr[5]; |
225 | const char *addrfam; | |
226 | int port; | |
f164f167 | 227 | switch (addr->sa.sa_family) { |
a32d56fb | 228 | case AF_INET: |
f164f167 | 229 | sprintf(addrstr,"%08lX",(long)addr->sin.sin_addr.s_addr); |
3ff31eda IJ |
230 | port=addr->sin.sin_port; |
231 | addrfam=NULL; | |
a32d56fb | 232 | break; |
3ff31eda IJ |
233 | #ifdef CONFIG_IPV6 |
234 | case AF_INET6: { | |
235 | int i; | |
236 | for (i=0; i<16; i++) | |
237 | sprintf(addrstr+i*2,"%02X",addr->sin6.sin6_addr.s6_addr[i]); | |
238 | port=addr->sin6.sin6_port; | |
239 | addrfam="6"; | |
240 | break; | |
241 | } | |
242 | #endif /*CONFIG_IPV6*/ | |
a32d56fb IJ |
243 | default: |
244 | fatal("udp (%s:%d): unsupported address family for authbind", | |
7d31df0e | 245 | cc->loc.file,cc->loc.line); |
a32d56fb | 246 | } |
3ff31eda | 247 | sprintf(portstr,"%04X",port); |
7d31df0e | 248 | argv[0]=uc->authbind; |
3b83c932 SE |
249 | argv[1]=addrstr; |
250 | argv[2]=portstr; | |
3ff31eda IJ |
251 | argv[3]=(char*)addrfam; |
252 | argv[4]=NULL; | |
f164f167 | 253 | dup2(us->fd,0); |
7d31df0e | 254 | execvp(uc->authbind,argv); |
3b83c932 | 255 | _exit(255); |
b2a56f7c | 256 | } |
3b83c932 SE |
257 | while (waitpid(c,&status,0)==-1) { |
258 | if (errno==EINTR) continue; | |
53f4e666 | 259 | FAIL("waitpid for authbind"); |
b2a56f7c | 260 | } |
4ac7fd3f IJ |
261 | if (status) { |
262 | lg_exitstatus(FAIL_LG,status,"authbind"); | |
53f4e666 | 263 | goto failed; |
3b83c932 | 264 | } |
b2a56f7c | 265 | } else { |
53f4e666 IJ |
266 | if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0) |
267 | FAIL("bind (%s)",iaddr_to_string(addr)); | |
baa06aeb | 268 | } |
53f4e666 IJ |
269 | return True; |
270 | ||
271 | failed: | |
272 | if (us->fd>=0) { | |
273 | close(us->fd); | |
274 | us->fd=-1; | |
275 | } | |
276 | return False; | |
277 | ||
278 | #undef FAIL | |
f164f167 | 279 | } |
baa06aeb | 280 | |
f7af3192 IJ |
281 | void udp_socks_register(struct udpcommon *uc, struct udpsocks *socks) |
282 | { | |
283 | socks->uc=uc; | |
5c679ae0 IJ |
284 | socks->interest= |
285 | register_for_poll(socks,udp_socks_beforepoll,udp_socks_afterpoll,"udp"); | |
286 | } | |
287 | ||
288 | void udp_socks_deregister(struct udpcommon *uc, struct udpsocks *socks) | |
289 | { | |
290 | socks->uc=uc; | |
291 | deregister_for_poll(socks->interest); | |
f7af3192 IJ |
292 | } |
293 | ||
f164f167 IJ |
294 | static void udp_phase_hook(void *sst, uint32_t new_phase) |
295 | { | |
296 | struct udp *st=sst; | |
763e458f | 297 | struct udpsocks *socks=&st->socks; |
f7af3192 | 298 | struct udpcommon *uc=&st->uc; |
08b62a6c | 299 | int i; |
7d31df0e | 300 | for (i=0; i<socks->n_socks; i++) |
53f4e666 | 301 | udp_make_socket(uc,&socks->socks[i],M_FATAL); |
08b62a6c | 302 | |
f7af3192 | 303 | udp_socks_register(uc,socks); |
baa06aeb SE |
304 | } |
305 | ||
2fe58dfd SE |
306 | static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context, |
307 | list_t *args) | |
308 | { | |
309 | struct udp *st; | |
08b62a6c | 310 | list_t *caddrl; |
ff05a229 SE |
311 | list_t *l; |
312 | uint32_t a; | |
08b62a6c | 313 | int i; |
2fe58dfd | 314 | |
763e458f IJ |
315 | COMM_APPLY(st,&st->uc.cc,udp_,"udp",loc); |
316 | COMM_APPLY_STANDARD(st,&st->uc.cc,"udp",args); | |
317 | UDP_APPLY_STANDARD(st,&st->uc,"udp"); | |
2fe58dfd | 318 | |
763e458f IJ |
319 | struct udpcommon *uc=&st->uc; |
320 | struct udpsocks *socks=&st->socks; | |
321 | struct commcommon *cc=&uc->cc; | |
08b62a6c IJ |
322 | |
323 | union iaddr defaultaddrs[] = { | |
324 | #ifdef CONFIG_IPV6 | |
325 | { .sin6 = { .sin6_family=AF_INET6, | |
763e458f | 326 | .sin6_port=htons(uc->port), |
08b62a6c IJ |
327 | .sin6_addr=IN6ADDR_ANY_INIT } }, |
328 | #endif | |
329 | { .sin = { .sin_family=AF_INET, | |
763e458f | 330 | .sin_port=htons(uc->port), |
08b62a6c IJ |
331 | .sin_addr= { .s_addr=INADDR_ANY } } } |
332 | }; | |
333 | ||
334 | caddrl=dict_lookup(d,"address"); | |
7d31df0e IJ |
335 | socks->n_socks=caddrl ? list_length(caddrl) : (int)ARRAY_SIZE(defaultaddrs); |
336 | if (socks->n_socks<=0 || socks->n_socks>UDP_MAX_SOCKETS) | |
337 | cfgfatal(cc->loc,"udp","`address' must be 1..%d addresses", | |
338 | UDP_MAX_SOCKETS); | |
08b62a6c | 339 | |
7d31df0e IJ |
340 | for (i=0; i<socks->n_socks; i++) { |
341 | struct udpsock *us=&socks->socks[i]; | |
08b62a6c IJ |
342 | if (!list_length(caddrl)) { |
343 | us->addr=defaultaddrs[i]; | |
344 | } else { | |
763e458f | 345 | string_item_to_iaddr(list_elem(caddrl,i),uc->port,&us->addr,"udp"); |
08b62a6c IJ |
346 | } |
347 | us->fd=-1; | |
348 | } | |
349 | ||
ff05a229 SE |
350 | l=dict_lookup(d,"proxy"); |
351 | if (l) { | |
7d31df0e IJ |
352 | uc->use_proxy=True; |
353 | uc->proxy.sa.sa_family=AF_INET; | |
c649eafe IJ |
354 | item=list_elem(l,0); |
355 | if (!item || item->type!=t_string) { | |
7d31df0e | 356 | cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n"); |
ff05a229 | 357 | } |
c649eafe | 358 | a=string_item_to_ipaddr(item,"proxy"); |
7d31df0e | 359 | uc->proxy.sin.sin_addr.s_addr=htonl(a); |
c649eafe IJ |
360 | item=list_elem(l,1); |
361 | if (!item || item->type!=t_number) { | |
7d31df0e | 362 | cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n"); |
ff05a229 | 363 | } |
7d31df0e | 364 | uc->proxy.sin.sin_port=htons(item->data.number); |
ff05a229 | 365 | } |
2fe58dfd | 366 | |
7d31df0e | 367 | update_max_start_pad(&comm_max_start_pad, uc->use_proxy ? 8 : 0); |
3abd18e8 | 368 | |
baa06aeb | 369 | add_hook(PHASE_GETRESOURCES,udp_phase_hook,st); |
2fe58dfd | 370 | |
7d31df0e | 371 | return new_closure(&cc->cl); |
2fe58dfd SE |
372 | } |
373 | ||
2fe58dfd SE |
374 | void udp_module(dict_t *dict) |
375 | { | |
376 | add_closure(dict,"udp",udp_apply); | |
377 | } |