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;
33 struct comm_notify_entry {
36 LIST_ENTRY(comm_notify_entry) entry;
38 LIST_HEAD(comm_notify_list, comm_notify_entry) notify;
40 #define UDP_MAX_SOCKETS 3 /* 2 ought to do really */
52 struct udpsock socks[UDP_MAX_SOCKETS];
54 struct buffer_if *rbuf;
55 struct comm_notify_list notify;
61 * Re comm_addr.ix: This field allows us to note in the comm_addr
62 * which socket an incoming packet was received on. This is required
63 * for conveniently logging the actual source of a packet. But the ix
64 * does not formally form part of the address: it is not used when
65 * sending, nor when comparing two comm_addrs.
67 * The special value -1 means that the comm_addr was constructed by
68 * another module in secnet (eg the resolver), rather than being a
69 * description of the source of an incoming packet.
72 static const char *addr_to_string(void *commst, const struct comm_addr *ca) {
73 struct udp *st=commst;
74 struct udp *socks=st; /* for now */
75 static char sbuf[100];
76 int ix=ca->ix>=0 ? ca->ix : 0;
78 assert(ix>=0 && ix<socks->n_socks);
79 snprintf(sbuf, sizeof(sbuf), "udp:%s%s-%s",
80 iaddr_to_string(&socks->socks[ix].addr),
82 iaddr_to_string(&ca->ia));
86 static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
91 struct udp *socks=st; /* for now */
92 BEFOREPOLL_WANT_FDS(socks->n_socks);
93 for (i=0; i<socks->n_socks; i++) {
94 fds[i].fd=socks->socks[i].fd;
100 static void udp_afterpoll(void *state, struct pollfd *fds, int nfds)
102 struct udp *st=state;
103 struct udp *socks=st; /* for now */
104 struct udp *cc=st; /* for now */
105 struct udp *uc=st; /* for now */
108 struct comm_notify_entry *n;
113 for (i=0; i<st->n_socks; i++) {
114 if (i>=nfds) continue;
115 if (!(fds[i].revents & POLLIN)) continue;
116 assert(fds[i].fd == socks->socks[i].fd);
117 int fd=socks->socks[i].fd;
119 fromlen=sizeof(from);
120 BUF_ASSERT_FREE(cc->rbuf);
121 BUF_ALLOC(cc->rbuf,"udp_afterpoll");
122 buffer_init(cc->rbuf,calculate_max_start_pad());
123 rv=recvfrom(fd, cc->rbuf->start,
124 buf_remaining_space(cc->rbuf),
125 0, &from.sa, &fromlen);
129 /* Check that the packet came from our poxy server;
130 we shouldn't be contacted directly by anybody else
131 (since they can trivially forge source addresses) */
132 if (!iaddr_equal(&from,&uc->proxy)) {
133 Message(M_INFO,"udp: received packet that's not "
138 /* proxy protocol supports ipv4 transport only */
139 from.sa.sa_family=AF_INET;
140 BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_addr,4);
141 buf_unprepend(cc->rbuf,2);
142 BUF_GET_BYTES(unprepend,cc->rbuf,&from.sin.sin_port,2);
149 LIST_FOREACH(n, &cc->notify, entry) {
150 if (n->fn(n->state, cc->rbuf, &ca)) {
157 if (cc->rbuf->size>12 /* prevents traffic amplification */
158 && ((msgtype=get_uint32(cc->rbuf->start+8))
160 uint32_t source,dest;
161 /* Manufacture and send NAK packet */
162 source=get_uint32(cc->rbuf->start); /* Us */
163 dest=get_uint32(cc->rbuf->start+4); /* Them */
164 send_nak(&ca,source,dest,msgtype,cc->rbuf,"unwanted");
168 BUF_ASSERT_FREE(cc->rbuf);
176 static void request_notify(void *commst, void *nst, comm_notify_fn *fn)
178 struct udp *st=commst;
179 struct udp *cc=st; /* for now */
180 struct comm_notify_entry *n;
182 n=safe_malloc(sizeof(*n),"request_notify");
185 LIST_INSERT_HEAD(&cc->notify, n, entry);
188 static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
190 struct udp *st=commst;
191 struct udp *cc=st; /* for now */
192 struct comm_notify_entry *n, *t;
195 LIST_FOREACH_SAFE(n, &cc->notify, entry, t) {
196 if (n->state==nst && n->fn==fn) {
197 LIST_REMOVE(n, entry);
203 static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
204 const struct comm_addr *dest)
206 struct udp *st=commst;
207 struct udp *uc=st; /* for now */
208 struct udp *socks=st; /* for now */
212 sa=buf_prepend(buf,8);
213 if (dest->ia.sa.sa_family != AF_INET) {
215 "udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
216 iaddr_to_string(&dest->ia));
219 memcpy(sa,&dest->ia.sin.sin_addr,4);
221 memcpy(sa+6,&dest->ia.sin.sin_port,2);
222 sendto(socks->socks[0].fd,sa,buf->size+8,0,&uc->proxy.sa,
223 iaddr_socklen(&uc->proxy));
224 buf_unprepend(buf,8);
227 bool_t allunsupported=True;
228 for (i=0; i<socks->n_socks; i++) {
229 if (dest->ia.sa.sa_family != socks->socks[i].addr.sa.sa_family)
230 /* no point even trying */
232 r=sendto(socks->socks[i].fd, buf->start, buf->size, 0,
233 &dest->ia.sa, iaddr_socklen(&dest->ia));
234 if (r>=0) return True;
235 if (!(errno==EAFNOSUPPORT || errno==ENETUNREACH))
236 /* who knows what that error means? */
237 allunsupported=False;
239 return !allunsupported; /* see doc for comm_sendmsg_fn in secnet.h */
245 static void udp_make_socket(struct udp *st, struct udpsock *us)
247 const union iaddr *addr=&us->addr;
248 struct udp *cc=st; /* for now */
249 struct udp *uc=st; /* for now */
250 us->fd=socket(addr->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP);
252 fatal_perror("udp (%s:%d): socket",cc->loc.file,cc->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 cc->loc.file,cc->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 cc->loc.file,cc->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 cc->loc.file,cc->loc.line);
304 sprintf(portstr,"%04X",port);
305 argv[0]=uc->authbind;
308 argv[3]=(char*)addrfam;
311 execvp(uc->authbind,argv);
314 while (waitpid(c,&status,0)==-1) {
315 if (errno==EINTR) continue;
316 fatal_perror("udp (%s:%d): authbind",cc->loc.file,cc->loc.line);
318 if (WIFSIGNALED(status)) {
319 fatal("udp (%s:%d): authbind died on signal %d",cc->loc.file,
320 cc->loc.line, WTERMSIG(status));
322 if (WIFEXITED(status) && WEXITSTATUS(status)!=0) {
323 fatal("udp (%s:%d): authbind died with status %d",cc->loc.file,
324 cc->loc.line, WEXITSTATUS(status));
327 if (bind(us->fd, &addr->sa, iaddr_socklen(addr))!=0) {
328 fatal_perror("udp (%s:%d): bind",cc->loc.file,cc->loc.line);
333 static void udp_phase_hook(void *sst, uint32_t new_phase)
336 struct udp *socks=st; /* for now */
338 for (i=0; i<socks->n_socks; i++)
339 udp_make_socket(st,&socks->socks[i]);
341 register_for_poll(st,udp_beforepoll,udp_afterpoll,"udp");
344 static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
355 st=safe_malloc(sizeof(*st),"udp_apply(st)");
356 struct udp *cc=st; /* for now */
357 struct udp *uc=st; /* for now */
358 struct udp *socks=st; /* for now */
360 cc->cl.description="udp";
363 cc->cl.interface=&cc->ops;
365 cc->ops.request_notify=request_notify;
366 cc->ops.release_notify=release_notify;
367 cc->ops.sendmsg=udp_sendmsg;
368 cc->ops.addr_to_string=addr_to_string;
370 LIST_INIT(&cc->notify);
372 item=list_elem(args,0);
373 if (!item || item->type!=t_dict) {
374 cfgfatal(cc->loc,"udp","first argument must be a dictionary\n");
378 int port=dict_read_number(d,"port",True,"udp",cc->loc,0);
380 union iaddr defaultaddrs[] = {
382 { .sin6 = { .sin6_family=AF_INET6,
383 .sin6_port=htons(port),
384 .sin6_addr=IN6ADDR_ANY_INIT } },
386 { .sin = { .sin_family=AF_INET,
387 .sin_port=htons(port),
388 .sin_addr= { .s_addr=INADDR_ANY } } }
391 caddrl=dict_lookup(d,"address");
392 socks->n_socks=caddrl ? list_length(caddrl) : (int)ARRAY_SIZE(defaultaddrs);
393 if (socks->n_socks<=0 || socks->n_socks>UDP_MAX_SOCKETS)
394 cfgfatal(cc->loc,"udp","`address' must be 1..%d addresses",
397 for (i=0; i<socks->n_socks; i++) {
398 struct udpsock *us=&socks->socks[i];
399 if (!list_length(caddrl)) {
400 us->addr=defaultaddrs[i];
402 string_item_to_iaddr(list_elem(caddrl,i),port,&us->addr,"udp");
407 cc->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",cc->loc);
408 uc->authbind=dict_read_string(d,"authbind",False,"udp",cc->loc);
409 l=dict_lookup(d,"proxy");
412 uc->proxy.sa.sa_family=AF_INET;
414 if (!item || item->type!=t_string) {
415 cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n");
417 a=string_item_to_ipaddr(item,"proxy");
418 uc->proxy.sin.sin_addr.s_addr=htonl(a);
420 if (!item || item->type!=t_number) {
421 cfgfatal(cc->loc,"udp","proxy must supply ""addr"",port\n");
423 uc->proxy.sin.sin_port=htons(item->data.number);
426 update_max_start_pad(&comm_max_start_pad, uc->use_proxy ? 8 : 0);
428 add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
430 return new_closure(&cc->cl);
433 void udp_module(dict_t *dict)
435 add_closure(dict,"udp",udp_apply);