1 /* UDP send/receive module for secnet */
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
8 * Packets are offered to registered receivers in turn. Once one
9 * accepts it, it isn't offered to any more. */
17 #include <sys/socket.h>
19 #include <netinet/in.h>
20 #include <arpa/inet.h>
23 #include "unaligned.h"
26 #include "comm-common.h"
28 static comm_sendmsg_fn udp_sendmsg;
32 struct udpsocks socks;
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.
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.
47 static const char *udp_addr_to_string(void *commst, const struct comm_addr *ca)
49 struct udp *st=commst;
50 struct udpsocks *socks=&st->socks;
51 static char sbuf[100];
52 int ix=ca->ix>=0 ? ca->ix : 0;
54 assert(ix>=0 && ix<socks->n_socks);
55 snprintf(sbuf, sizeof(sbuf), "udp:%s%s-%s",
56 iaddr_to_string(&socks->socks[ix].addr),
57 ca->ix<0 && socks->n_socks>1 ? "&" : "",
58 iaddr_to_string(&ca->ia));
62 static int udp_socks_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
65 struct udpsocks *socks=state;
67 BEFOREPOLL_WANT_FDS(socks->n_socks);
68 for (i=0; i<socks->n_socks; i++) {
69 fds[i].fd=socks->socks[i].fd;
75 const char *af_name(int af)
78 case AF_INET6: return "IPv6";
79 case AF_INET: return "IPv4";
80 case 0: return "(any)";
85 void udp_sock_experienced(struct log_if *lg, struct udpcommon *uc,
86 struct udpsocks *socks, struct udpsock *us,
87 const union iaddr *dest, int af,
91 if (us->experienced[!!dest][af][success]++)
93 lg_perror(lg, uc->cc.cl.description, &uc->cc.loc,
94 success ? M_INFO : M_WARNING,
95 success ? 0 : errnoval,
96 "%s %s experiencing some %s %s%s%s%s%s%s",
97 socks->desc,iaddr_to_string(&us->addr),
98 success?"success":"trouble",
99 dest?"transmitting":"receiving",
100 af?" ":"", af?af_name(af):"",
102 dest?iaddr_to_string(dest):"",
106 static void udp_socks_afterpoll(void *state, struct pollfd *fds, int nfds)
108 struct udpsocks *socks=state;
109 struct udpcommon *uc=socks->uc;
116 struct commcommon *cc=&uc->cc;
118 for (i=0; i<socks->n_socks; i++) {
119 struct udpsock *us=&socks->socks[i];
120 if (i>=nfds) continue;
121 if (!(fds[i].revents & POLLIN)) continue;
122 assert(fds[i].fd == us->fd);
125 fromlen=sizeof(from);
126 BUF_ASSERT_FREE(cc->rbuf);
127 BUF_ALLOC(cc->rbuf,"udp_afterpoll");
128 buffer_init(cc->rbuf,calculate_max_start_pad());
129 rv=recvfrom(fd, cc->rbuf->start,
130 buf_remaining_space(cc->rbuf),
131 0, &from.sa, &fromlen);
135 /* Check that the packet came from our poxy server;
136 we shouldn't be contacted directly by anybody else
137 (since they can trivially forge source addresses) */
138 if (!iaddr_equal(&from,&uc->proxy,False)) {
139 Message(M_INFO,"udp: received packet that's not "
144 /* proxy protocol supports ipv4 transport only */
145 from.sa.sa_family=AF_INET;
146 BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_addr,4);
147 buf_unprepend(cc->rbuf,2);
148 BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_port,2);
154 done=comm_notify(&cc->notify, cc->rbuf, &ca);
156 udp_sock_experienced(0,uc,socks,us,0,
157 from.sa.sa_family,0,0);
160 if (cc->rbuf->size>12 /* prevents traffic amplification */
161 && ((msgtype=get_uint32(cc->rbuf->start+8))
163 uint32_t source,dest;
164 /* Manufacture and send NAK packet */
165 source=get_uint32(cc->rbuf->start); /* Us */
166 dest=get_uint32(cc->rbuf->start+4); /* Them */
167 send_nak(&ca,source,dest,msgtype,cc->rbuf,"unwanted");
171 BUF_ASSERT_FREE(cc->rbuf);
173 if (errno!=EINTR && !iswouldblock(errno))
174 udp_sock_experienced(0,uc,socks,us, 0,0, rv,errno);
181 static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
182 const struct comm_addr *dest)
184 struct udp *st=commst;
185 struct udpcommon *uc=&st->uc;
186 struct udpsocks *socks=&st->socks;
190 struct udpsock *us=&socks->socks[0];
191 sa=buf_prepend(buf,8);
192 if (dest->ia.sa.sa_family != AF_INET) {
194 "udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
195 iaddr_to_string(&dest->ia));
198 memcpy(sa,&dest->ia.sin.sin_addr,4);
200 memcpy(sa+6,&dest->ia.sin.sin_port,2);
201 int r=sendto(us->fd,sa,buf->size+8,0,&uc->proxy.sa,
202 iaddr_socklen(&uc->proxy));
203 udp_sock_experienced(0,uc,socks,us, &dest->ia,0, r,errno);
204 buf_unprepend(buf,8);
207 bool_t allunsupported=True;
208 int af=dest->ia.sa.sa_family;
209 for (i=0; i<socks->n_socks; i++) {
210 struct udpsock *us=&socks->socks[i];
211 if (us->addr.sa.sa_family != af)
212 /* no point even trying */
214 r=sendto(us->fd, buf->start, buf->size, 0,
215 &dest->ia.sa, iaddr_socklen(&dest->ia));
216 udp_sock_experienced(0,uc,socks,us, &dest->ia,af, r,errno);
217 if (r>=0) return True;
218 if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH))
219 /* who knows what that error means? */
220 allunsupported=False;
222 return !allunsupported; /* see doc for comm_sendmsg_fn in secnet.h */
228 void udp_destroy_socket(struct udpcommon *uc, struct udpsock *us)
236 #define FAIL_LG 0, cc->cl.description, &cc->loc, failmsgclass
237 #define FAIL(...) do{ \
238 lg_perror(FAIL_LG,errno,__VA_ARGS__); \
242 static bool_t record_socket_gotaddr(struct udpcommon *uc, struct udpsock *us,
245 struct commcommon *cc=&uc->cc;
246 socklen_t salen=sizeof(us->addr);
247 int r=getsockname(us->fd,&us->addr.sa,&salen);
248 if (r) FAIL("getsockname()");
249 if (salen>sizeof(us->addr)) { errno=0; FAIL("getsockname() length"); }
256 bool_t udp_import_socket(struct udpcommon *uc, struct udpsock *us,
257 int failmsgclass, int fd)
259 FILLZERO(us->experienced);
261 return record_socket_gotaddr(uc,us,failmsgclass);
264 bool_t udp_make_socket(struct udpcommon *uc, struct udpsock *us,
267 const union iaddr *addr=&us->addr;
268 struct commcommon *cc=&uc->cc;
271 FILLZERO(us->experienced);
272 us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
273 if (us->fd<0) FAIL("socket");
277 if (addr->sa.sa_family==AF_INET6) {
280 socklen_t optlen=sizeof(optval);
281 r=setsockopt(us->fd,IPPROTO_IPV6,IPV6_V6ONLY,&optval,optlen);
282 if (r) FAIL("setsockopt(,IPV6_V6ONLY,&1,)");
290 snprintf(desc,sizeof(desc),"authbind for %s: %s",
291 iaddr_to_string(addr), uc->authbind);
293 /* XXX this fork() and waitpid() business needs to be hidden
294 in some system-specific library functions. */
297 FAIL("fork() for authbind");
299 char *argv[5], addrstr[33], portstr[5];
303 switch (addr->sa.sa_family) {
305 sprintf(addrstr,"%08lX",(long)addr->sin.sin_addr.s_addr);
306 port=addr->sin.sin_port;
313 sprintf(addrstr+i*2,"%02X",addr->sin6.sin6_addr.s6_addr[i]);
314 port=addr->sin6.sin6_port;
318 #endif /*CONFIG_IPV6*/
320 fatal("udp (%s:%d): unsupported address family for authbind",
321 cc->loc.file,cc->loc.line);
323 sprintf(portstr,"%04X",port);
324 argv[0]=uc->authbind;
327 argv[3]=(char*)addrfam;
330 execvp(uc->authbind,argv);
333 while (waitpid(c,&status,0)==-1) {
334 if (errno==EINTR) continue;
335 FAIL("waitpid for authbind");
338 if (WIFEXITED(status) && WEXITSTATUS(status)<127) {
339 int es=WEXITSTATUS(status);
340 lg_perror(FAIL_LG,es,
341 "%s exited with error exit status %d;"
342 " indicates error",desc,es);
344 lg_exitstatus(FAIL_LG,status,desc);
349 if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0)
350 FAIL("bind (%s)",iaddr_to_string(addr));
353 bool_t ok=record_socket_gotaddr(uc,us,failmsgclass);
354 if (!ok) goto failed;
359 udp_destroy_socket(uc,us);
365 void udp_socks_register(struct udpcommon *uc, struct udpsocks *socks,
371 register_for_poll(socks,udp_socks_beforepoll,udp_socks_afterpoll,"udp");
374 void udp_socks_deregister(struct udpcommon *uc, struct udpsocks *socks)
377 deregister_for_poll(socks->interest);
380 void udp_socks_childpersist(struct udpcommon *uc, struct udpsocks *socks)
383 for (i=0; i<socks->n_socks; i++)
384 udp_destroy_socket(uc,&socks->socks[i]);
387 static void udp_childpersist_hook(void *sst, uint32_t new_phase)
390 udp_socks_childpersist(&st->uc,&st->socks);
393 static void udp_phase_hook(void *sst, uint32_t new_phase)
396 struct udpsocks *socks=&st->socks;
397 struct udpcommon *uc=&st->uc;
399 for (i=0; i<socks->n_socks; i++)
400 udp_make_socket(uc,&socks->socks[i],M_FATAL);
402 udp_socks_register(uc,socks, uc->use_proxy ? "proxy" : "socket");
404 add_hook(PHASE_CHILDPERSIST,udp_childpersist_hook,st);
407 static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
416 COMM_APPLY(st,&st->uc.cc,udp_,"udp",loc);
417 COMM_APPLY_STANDARD(st,&st->uc.cc,"udp",args);
418 UDP_APPLY_STANDARD(st,&st->uc,"udp");
420 struct udpcommon *uc=&st->uc;
421 struct udpsocks *socks=&st->socks;
422 struct commcommon *cc=&uc->cc;
424 union iaddr defaultaddrs[] = {
426 { .sin6 = { .sin6_family=AF_INET6,
427 .sin6_port=htons(uc->port),
428 .sin6_addr=IN6ADDR_ANY_INIT } },
430 { .sin = { .sin_family=AF_INET,
431 .sin_port=htons(uc->port),
432 .sin_addr= { .s_addr=INADDR_ANY } } }
435 caddrl=dict_lookup(d,"address");
436 socks->n_socks=caddrl ? list_length(caddrl) : (int)ARRAY_SIZE(defaultaddrs);
437 if (socks->n_socks<=0 || socks->n_socks>UDP_MAX_SOCKETS)
438 cfgfatal(cc->loc,"udp","`address' must be 1..%d addresses",
441 for (i=0; i<socks->n_socks; i++) {
442 struct udpsock *us=&socks->socks[i];
443 if (!list_length(caddrl)) {
444 us->addr=defaultaddrs[i];
446 string_item_to_iaddr(list_elem(caddrl,i),uc->port,&us->addr,"udp");
451 l=dict_lookup(d,"proxy");
454 uc->proxy.sa.sa_family=AF_INET;
456 if (!item || item->type!=t_string) {
457 cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n");
459 a=string_item_to_ipaddr(item,"proxy");
460 uc->proxy.sin.sin_addr.s_addr=htonl(a);
462 if (!item || item->type!=t_number) {
463 cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n");
465 uc->proxy.sin.sin_port=htons(item->data.number);
468 update_max_start_pad(&comm_max_start_pad, uc->use_proxy ? 8 : 0);
470 add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
472 return new_closure(&cc->cl);
475 void udp_module(dict_t *dict)
477 add_closure(dict,"udp",udp_apply);