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"
27 static beforepoll_fn udp_beforepoll;
28 static afterpoll_fn udp_afterpoll;
29 static comm_request_notify_fn request_notify;
30 static comm_release_notify_fn release_notify;
31 static comm_sendmsg_fn udp_sendmsg;
36 struct notify_list *next;
39 #define MAX_SOCKETS 3 /* 2 ought to do really */
51 struct udpsock socks[MAX_SOCKETS];
53 struct buffer_if *rbuf;
54 struct notify_list *notify;
60 * Re comm_addr.ix: This field allows us to note in the comm_addr
61 * which socket an incoming packet was received on. This is required
62 * for conveniently logging the actual source of a packet. But the ix
63 * does not formally form part of the address: it is not used when
64 * sending, nor when comparing two comm_addrs.
66 * The special value -1 means that the comm_addr was constructed by
67 * another module in secnet (eg the resolver), rather than being a
68 * description of the source of an incoming packet.
71 static const char *addr_to_string(void *commst, const struct comm_addr *ca) {
72 struct udp *st=commst;
73 static char sbuf[100];
74 int ix=ca->ix>=0 ? ca->ix : 0;
76 assert(ix>=0 && ix<st->n_socks);
77 snprintf(sbuf, sizeof(sbuf), "udp:%s%s-%s",
78 iaddr_to_string(&st->socks[ix].addr),
80 iaddr_to_string(&ca->ia));
84 static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
89 if (*nfds_io<st->n_socks) {
94 for (i=0; i<st->n_socks; i++) {
95 fds[i].fd=st->socks[i].fd;
101 static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
103 struct udp *st=state;
106 struct notify_list *n;
111 for (i=0; i<st->n_socks; i++) {
112 if (i>=nfds) continue;
113 if (!(fds[i].revents & POLLIN)) continue;
114 assert(fds[i].fd == st->socks[i].fd);
115 int fd=st->socks[i].fd;
117 fromlen=sizeof(from);
118 BUF_ASSERT_FREE(st->rbuf);
119 BUF_ALLOC(st->rbuf,"udp_afterpoll");
120 buffer_init(st->rbuf,calculate_max_start_pad());
121 rv=recvfrom(fd, st->rbuf->start,
122 buf_remaining_space(st->rbuf),
123 0, &from.sa, &fromlen);
127 /* Check that the packet came from our poxy server;
128 we shouldn't be contacted directly by anybody else
129 (since they can trivially forge source addresses) */
130 if (!iaddr_equal(&from,&st->proxy)) {
131 Message(M_INFO,"udp: received packet that's not "
136 /* proxy protocol supports ipv4 transport only */
137 from.sa.sa_family=AF_INET;
138 memcpy(&from.sin.sin_addr,buf_unprepend(st->rbuf,4),4);
139 buf_unprepend(st->rbuf,2);
140 memcpy(&from.sin.sin_port,buf_unprepend(st->rbuf,2),2);
147 for (n=st->notify; n; n=n->next) {
148 if (n->fn(n->state, st->rbuf, &ca)) {
155 if (st->rbuf->size>12 /* prevents traffic amplification */
156 && ((msgtype=get_uint32(st->rbuf->start+8))
158 uint32_t source,dest;
159 /* Manufacture and send NAK packet */
160 source=get_uint32(st->rbuf->start); /* Us */
161 dest=get_uint32(st->rbuf->start+4); /* Them */
162 send_nak(&ca,source,dest,msgtype,st->rbuf,"unwanted");
166 BUF_ASSERT_FREE(st->rbuf);
174 static void request_notify(void *commst, void *nst, comm_notify_fn *fn)
176 struct udp *st=commst;
177 struct notify_list *n;
179 n=safe_malloc(sizeof(*n),"request_notify");
186 static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
188 struct udp *st=commst;
189 struct notify_list *n, **p, *t;
193 for (n=st->notify; n; )
195 if (n->state==nst && n->fn==fn) {
207 static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
208 const struct comm_addr *dest)
210 struct udp *st=commst;
214 sa=buf_prepend(buf,8);
215 if (dest->ia.sa.sa_family != AF_INET) {
217 "udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
218 iaddr_to_string(&dest->ia));
221 memcpy(sa,&dest->ia.sin.sin_addr,4);
223 memcpy(sa+6,&dest->ia.sin.sin_port,2);
224 sendto(st->socks[0].fd,sa,buf->size+8,0,&st->proxy.sa,
225 iaddr_socklen(&st->proxy));
226 buf_unprepend(buf,8);
229 bool_t allunsupported=True;
230 for (i=0; i<st->n_socks; i++) {
231 if (dest->ia.sa.sa_family != st->socks[i].addr.sa.sa_family)
232 /* no point even trying */
234 r=sendto(st->socks[i].fd, buf->start, buf->size, 0,
235 &dest->ia.sa, iaddr_socklen(&dest->ia));
236 if (r>=0) return True;
237 if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH))
238 /* who knows what that error means? */
239 allunsupported=False;
241 return !allunsupported; /* see doc for comm_sendmsg_fn in secnet.h */
247 static void udp_make_socket(struct udp *st, struct udpsock *us)
249 const union iaddr *addr=&us->addr;
250 us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
252 fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line);
254 if (fcntl(us->fd, F_SETFL, fcntl(us->fd, F_GETFL)|O_NONBLOCK)==-1) {
255 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
256 st->loc.file,st->loc.line);
260 if (addr->sa.sa_family==AF_INET6) {
263 socklen_t optlen=sizeof(optval);
264 r=setsockopt(us->fd,IPPROTO_IPV6,IPV6_V6ONLY,&optval,optlen);
265 if (r) fatal_perror("udp (%s:%d): setsockopt(,IPV6_V6ONLY,&1,)",
266 st->loc.file,st->loc.line);
274 /* XXX this fork() and waitpid() business needs to be hidden
275 in some system-specific library functions. */
278 fatal_perror("udp_phase_hook: fork() for authbind");
281 char *argv[5], addrstr[33], portstr[5];
284 switch (addr->sa.sa_family) {
286 sprintf(addrstr,"%08lX",(long)addr->sin.sin_addr.s_addr);
287 port=addr->sin.sin_port;
294 sprintf(addrstr+i*2,"%02X",addr->sin6.sin6_addr.s6_addr[i]);
295 port=addr->sin6.sin6_port;
299 #endif /*CONFIG_IPV6*/
301 fatal("udp (%s:%d): unsupported address family for authbind",
302 st->loc.file,st->loc.line);
304 sprintf(portstr,"%04X",port);
305 argv[0]=st->authbind;
308 argv[3]=(char*)addrfam;
311 execvp(st->authbind,argv);
314 while (waitpid(c,&status,0)==-1) {
315 if (errno==EINTR) continue;
316 fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line);
318 if (WIFSIGNALED(status)) {
319 fatal("udp (%s:%d): authbind died on signal %d",st->loc.file,
320 st->loc.line, WTERMSIG(status));
322 if (WIFEXITED(status) && WEXITSTATUS(status)!=0) {
323 fatal("udp (%s:%d): authbind died with status %d",st->loc.file,
324 st->loc.line, WEXITSTATUS(status));
327 if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0) {
328 fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
333 static void udp_phase_hook(void *sst, uint32_t new_phase)
337 for (i=0; i<st->n_socks; i++)
338 udp_make_socket(st,&st->socks[i]);
340 register_for_poll(st,udp_beforepoll,udp_afterpoll,MAX_SOCKETS,"udp");
343 static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
354 st=safe_malloc(sizeof(*st),"udp_apply(st)");
356 st->cl.description="udp";
359 st->cl.interface=&st->ops;
361 st->ops.request_notify=request_notify;
362 st->ops.release_notify=release_notify;
363 st->ops.sendmsg=udp_sendmsg;
364 st->ops.addr_to_string=addr_to_string;
367 item=list_elem(args,0);
368 if (!item || item->type!=t_dict) {
369 cfgfatal(st->loc,"udp","first argument must be a dictionary\n");
373 int port=dict_read_number(d,"port",True,"udp",st->loc,0);
375 union iaddr defaultaddrs[] = {
377 { .sin6 = { .sin6_family=AF_INET6,
378 .sin6_port=htons(port),
379 .sin6_addr=IN6ADDR_ANY_INIT } },
381 { .sin = { .sin_family=AF_INET,
382 .sin_port=htons(port),
383 .sin_addr= { .s_addr=INADDR_ANY } } }
386 caddrl=dict_lookup(d,"address");
387 st->n_socks=caddrl ? list_length(caddrl) : (int)ARRAY_SIZE(defaultaddrs);
388 if (st->n_socks<=0 || st->n_socks>MAX_SOCKETS)
389 cfgfatal(st->loc,"udp","`address' must be 1..%d addresses",
392 for (i=0; i<st->n_socks; i++) {
393 struct udpsock *us=&st->socks[i];
394 if (!list_length(caddrl)) {
395 us->addr=defaultaddrs[i];
397 string_item_to_iaddr(list_elem(caddrl,i),port,&us->addr,"udp");
402 st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc);
403 st->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
404 l=dict_lookup(d,"proxy");
407 st->proxy.sa.sa_family=AF_INET;
409 if (!item || item->type!=t_string) {
410 cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
412 a=string_item_to_ipaddr(item,"proxy");
413 st->proxy.sin.sin_addr.s_addr=htonl(a);
415 if (!item || item->type!=t_number) {
416 cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
418 st->proxy.sin.sin_port=htons(item->data.number);
421 update_max_start_pad(&comm_max_start_pad, st->use_proxy ? 8 : 0);
423 add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
425 return new_closure(&st->cl);
428 void udp_module(dict_t *dict)
430 add_closure(dict,"udp",udp_apply);