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;
33 bool_t addr_configured;
37 * Re comm_addr.ix: This field allows us to note in the comm_addr
38 * which socket an incoming packet was received on. This is required
39 * for conveniently logging the actual source of a packet. But the ix
40 * does not formally form part of the address: it is not used when
41 * sending, nor when comparing two comm_addrs.
43 * The special value -1 means that the comm_addr was constructed by
44 * another module in secnet (eg the resolver), rather than being a
45 * description of the source of an incoming packet.
48 static const char *udp_addr_to_string(void *commst, const struct comm_addr *ca)
50 struct udp *st=commst;
51 struct udpsocks *socks=&st->socks;
52 static char sbuf[100];
53 int ix=ca->ix>=0 ? ca->ix : 0;
55 assert(ix>=0 && ix<socks->n_socks);
56 snprintf(sbuf, sizeof(sbuf), "udp:%s%s-%s",
57 iaddr_to_string(&socks->socks[ix].addr),
58 ca->ix<0 && socks->n_socks>1 ? "&" : "",
59 iaddr_to_string(&ca->ia));
63 static int udp_socks_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
66 struct udpsocks *socks=state;
68 BEFOREPOLL_WANT_FDS(socks->n_socks);
69 for (i=0; i<socks->n_socks; i++) {
70 fds[i].fd=socks->socks[i].fd;
76 const char *af_name(int af)
79 case AF_INET6: return "IPv6";
80 case AF_INET: return "IPv4";
81 case 0: return "(any)";
86 void udp_sock_experienced(struct log_if *lg, struct udpcommon *uc,
87 struct udpsocks *socks, struct udpsock *us,
88 const union iaddr *dest, int af,
92 if (us->experienced[!!dest][af][success]++)
94 lg_perror(lg, uc->cc.cl.description, &uc->cc.loc,
95 success ? M_INFO : M_WARNING,
96 success ? 0 : errnoval,
97 "%s %s experiencing some %s %s%s%s%s%s%s",
98 socks->desc,iaddr_to_string(&us->addr),
99 success?"success":"trouble",
100 dest?"transmitting":"receiving",
101 af?" ":"", af?af_name(af):"",
103 dest?iaddr_to_string(dest):"",
107 static void udp_socks_afterpoll(void *state, struct pollfd *fds, int nfds)
109 struct udpsocks *socks=state;
110 struct udpcommon *uc=socks->uc;
117 struct commcommon *cc=&uc->cc;
119 for (i=0; i<socks->n_socks; i++) {
120 struct udpsock *us=&socks->socks[i];
121 if (i>=nfds) continue;
122 if (!(fds[i].revents & POLLIN)) continue;
123 assert(fds[i].fd == us->fd);
126 fromlen=sizeof(from);
127 BUF_ASSERT_FREE(cc->rbuf);
128 BUF_ALLOC(cc->rbuf,"udp_afterpoll");
129 buffer_init(cc->rbuf,calculate_max_start_pad());
130 rv=recvfrom(fd, cc->rbuf->start,
131 buf_remaining_space(cc->rbuf),
132 0, &from.sa, &fromlen);
136 /* Check that the packet came from our poxy server;
137 we shouldn't be contacted directly by anybody else
138 (since they can trivially forge source addresses) */
139 if (!iaddr_equal(&from,&uc->proxy,False)) {
140 Message(M_INFO,"udp: received packet that's not "
145 /* proxy protocol supports ipv4 transport only */
146 from.sa.sa_family=AF_INET;
147 BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_addr,4);
148 buf_unprepend(cc->rbuf,2);
149 BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_port,2);
155 done=comm_notify(&cc->notify, cc->rbuf, &ca);
157 udp_sock_experienced(0,uc,socks,us,0,
158 from.sa.sa_family,0,0);
161 if (cc->rbuf->size>12 /* prevents traffic amplification */
162 && ((msgtype=get_uint32(cc->rbuf->start+8))
164 uint32_t source,dest;
165 /* Manufacture and send NAK packet */
166 source=get_uint32(cc->rbuf->start); /* Us */
167 dest=get_uint32(cc->rbuf->start+4); /* Them */
168 send_nak(&ca,source,dest,msgtype,cc->rbuf,"unwanted");
172 BUF_ASSERT_FREE(cc->rbuf);
174 if (errno!=EINTR && !iswouldblock(errno))
175 udp_sock_experienced(0,uc,socks,us, 0,0, rv,errno);
182 static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
183 const struct comm_addr *dest)
185 struct udp *st=commst;
186 struct udpcommon *uc=&st->uc;
187 struct udpsocks *socks=&st->socks;
191 struct udpsock *us=&socks->socks[0];
192 sa=buf_prepend(buf,8);
193 if (dest->ia.sa.sa_family != AF_INET) {
195 "udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
196 iaddr_to_string(&dest->ia));
199 memcpy(sa,&dest->ia.sin.sin_addr,4);
201 memcpy(sa+6,&dest->ia.sin.sin_port,2);
202 int r=sendto(us->fd,sa,buf->size+8,0,&uc->proxy.sa,
203 iaddr_socklen(&uc->proxy));
204 udp_sock_experienced(0,uc,socks,us, &dest->ia,0, r,errno);
205 buf_unprepend(buf,8);
208 bool_t allunsupported=True;
209 int af=dest->ia.sa.sa_family;
210 for (i=0; i<socks->n_socks; i++) {
211 struct udpsock *us=&socks->socks[i];
212 if (us->addr.sa.sa_family != af)
213 /* no point even trying */
215 r=sendto(us->fd, buf->start, buf->size, 0,
216 &dest->ia.sa, iaddr_socklen(&dest->ia));
217 udp_sock_experienced(0,uc,socks,us, &dest->ia,af, r,errno);
218 if (r>=0) return True;
219 if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH))
220 /* who knows what that error means? */
221 allunsupported=False;
223 return !allunsupported; /* see doc for comm_sendmsg_fn in secnet.h */
229 void udp_destroy_socket(struct udpcommon *uc, struct udpsock *us)
237 #define FAIL_LG 0, cc->cl.description, &cc->loc, failmsgclass
238 #define FAIL(...) do{ \
239 lg_perror(FAIL_LG,errno,__VA_ARGS__); \
243 static bool_t record_socket_gotaddr(struct udpcommon *uc, struct udpsock *us,
246 struct commcommon *cc=&uc->cc;
247 socklen_t salen=sizeof(us->addr);
248 int r=getsockname(us->fd,&us->addr.sa,&salen);
249 if (r) FAIL("getsockname()");
250 if (salen>sizeof(us->addr)) { errno=0; FAIL("getsockname() length"); }
257 bool_t udp_import_socket(struct udpcommon *uc, struct udpsock *us,
258 int failmsgclass, int fd)
260 FILLZERO(us->experienced);
262 return record_socket_gotaddr(uc,us,failmsgclass);
265 bool_t udp_make_socket(struct udpcommon *uc, struct udpsock *us,
268 const union iaddr *addr=&us->addr;
269 struct commcommon *cc=&uc->cc;
272 FILLZERO(us->experienced);
273 us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
274 if (us->fd<0) FAIL("socket");
278 if (addr->sa.sa_family==AF_INET6) {
281 socklen_t optlen=sizeof(optval);
282 r=setsockopt(us->fd,IPPROTO_IPV6,IPV6_V6ONLY,&optval,optlen);
283 if (r) FAIL("setsockopt(,IPV6_V6ONLY,&1,)");
291 snprintf(desc,sizeof(desc),"authbind for %s: %s",
292 iaddr_to_string(addr), uc->authbind);
294 /* XXX this fork() and waitpid() business needs to be hidden
295 in some system-specific library functions. */
298 FAIL("fork() for authbind");
300 char *argv[5], addrstr[33], portstr[5];
304 switch (addr->sa.sa_family) {
306 sprintf(addrstr,"%08lX",(long)addr->sin.sin_addr.s_addr);
307 port=addr->sin.sin_port;
314 sprintf(addrstr+i*2,"%02X",addr->sin6.sin6_addr.s6_addr[i]);
315 port=addr->sin6.sin6_port;
319 #endif /*CONFIG_IPV6*/
321 fatal("udp (%s:%d): unsupported address family for authbind",
322 cc->loc.file,cc->loc.line);
324 sprintf(portstr,"%04X",port);
325 argv[0]=uc->authbind;
328 argv[3]=(char*)addrfam;
331 execvp(uc->authbind,argv);
334 while (waitpid(c,&status,0)==-1) {
335 if (errno==EINTR) continue;
336 FAIL("waitpid for authbind");
339 if (WIFEXITED(status) && WEXITSTATUS(status)<127) {
340 int es=WEXITSTATUS(status);
341 lg_perror(FAIL_LG,es,
342 "%s exited with error exit status %d;"
343 " indicates error",desc,es);
345 lg_exitstatus(FAIL_LG,status,desc);
350 if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0)
351 FAIL("bind (%s)",iaddr_to_string(addr));
354 bool_t ok=record_socket_gotaddr(uc,us,failmsgclass);
355 if (!ok) goto failed;
360 udp_destroy_socket(uc,us);
366 void udp_socks_register(struct udpcommon *uc, struct udpsocks *socks,
372 register_for_poll(socks,udp_socks_beforepoll,udp_socks_afterpoll,"udp");
375 void udp_socks_deregister(struct udpcommon *uc, struct udpsocks *socks)
378 deregister_for_poll(socks->interest);
381 void udp_socks_childpersist(struct udpcommon *uc, struct udpsocks *socks)
384 for (i=0; i<socks->n_socks; i++)
385 udp_destroy_socket(uc,&socks->socks[i]);
388 static void udp_childpersist_hook(void *sst, uint32_t new_phase)
391 udp_socks_childpersist(&st->uc,&st->socks);
394 static void udp_phase_hook(void *sst, uint32_t new_phase)
397 struct udpsocks *socks=&st->socks;
398 struct udpcommon *uc=&st->uc;
402 for (i=0; i<socks->n_socks; i++) {
403 bool_t required=st->addr_configured
404 || (!anydone && i==socks->n_socks-1);
405 anydone += udp_make_socket(uc,&socks->socks[i],
406 required ? M_FATAL : M_WARNING);
409 udp_socks_register(uc,socks, uc->use_proxy ? "proxy" : "socket");
411 add_hook(PHASE_CHILDPERSIST,udp_childpersist_hook,st);
414 static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
423 COMM_APPLY(st,&st->uc.cc,udp_,"udp",loc);
424 COMM_APPLY_STANDARD(st,&st->uc.cc,"udp",args);
425 UDP_APPLY_STANDARD(st,&st->uc,"udp");
427 struct udpcommon *uc=&st->uc;
428 struct udpsocks *socks=&st->socks;
429 struct commcommon *cc=&uc->cc;
431 union iaddr defaultaddrs[] = {
433 { .sin6 = { .sin6_family=AF_INET6,
434 .sin6_port=htons(uc->port),
435 .sin6_addr=IN6ADDR_ANY_INIT } },
437 { .sin = { .sin_family=AF_INET,
438 .sin_port=htons(uc->port),
439 .sin_addr= { .s_addr=INADDR_ANY } } }
442 caddrl=dict_lookup(d,"address");
443 st->addr_configured=!!caddrl;
444 socks->n_socks=st->addr_configured ? list_length(caddrl)
445 : (int)ARRAY_SIZE(defaultaddrs);
446 if (socks->n_socks<=0 || socks->n_socks>UDP_MAX_SOCKETS)
447 cfgfatal(cc->loc,"udp","`address' must be 1..%d addresses",
450 for (i=0; i<socks->n_socks; i++) {
451 struct udpsock *us=&socks->socks[i];
452 if (!st->addr_configured) {
453 us->addr=defaultaddrs[i];
455 string_item_to_iaddr(list_elem(caddrl,i),uc->port,&us->addr,"udp");
460 l=dict_lookup(d,"proxy");
463 uc->proxy.sa.sa_family=AF_INET;
465 if (!item || item->type!=t_string) {
466 cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n");
468 a=string_item_to_ipaddr(item,"proxy");
469 uc->proxy.sin.sin_addr.s_addr=htonl(a);
471 if (!item || item->type!=t_number) {
472 cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n");
474 uc->proxy.sin.sin_port=htons(item->data.number);
477 update_max_start_pad(&comm_max_start_pad, uc->use_proxy ? 8 : 0);
479 add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
481 return new_closure(&cc->cl);
484 void udp_module(dict_t *dict)
486 add_closure(dict,"udp",udp_apply);