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>
20 #include "unaligned.h"
23 static beforepoll_fn udp_beforepoll;
24 static afterpoll_fn udp_afterpoll;
25 static comm_request_notify_fn request_notify;
26 static comm_release_notify_fn release_notify;
27 static comm_sendmsg_fn udp_sendmsg;
32 struct notify_list *next;
43 struct buffer_if *rbuf;
44 struct notify_list *notify;
46 struct sockaddr_in proxy;
49 static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
50 int *timeout_io, const struct timeval *tv,
64 static void udp_afterpoll(void *state, struct pollfd *fds, int nfds,
65 const struct timeval *tv, uint64_t *now)
68 struct sockaddr_in from;
70 struct notify_list *n;
74 if (nfds && (fds->revents & POLLIN)) {
77 BUF_ASSERT_FREE(st->rbuf);
78 BUF_ALLOC(st->rbuf,"udp_afterpoll");
79 rv=recvfrom(st->fd, st->rbuf->start, st->rbuf->len, 0,
80 (struct sockaddr *)&from, &fromlen);
84 /* Check that the packet came from our poxy server;
85 we shouldn't be contacted directly by anybody else
86 (since they can trivially forge source addresses) */
87 if (memcmp(&from.sin_addr,&st->proxy.sin_addr,4)!=0 ||
88 memcmp(&from.sin_port,&st->proxy.sin_port,2)!=0) {
89 Message(M_INFO,"udp: received packet that's not "
94 memcpy(&from.sin_addr,buf_unprepend(st->rbuf,4),4);
95 buf_unprepend(st->rbuf,2);
96 memcpy(&from.sin_port,buf_unprepend(st->rbuf,2),2);
99 for (n=st->notify; n; n=n->next) {
100 if (n->fn(n->state, st->rbuf, &from)) {
106 uint32_t source,dest;
107 /* Manufacture and send NAK packet */
108 source=get_uint32(st->rbuf->start); /* Us */
109 dest=get_uint32(st->rbuf->start+4); /* Them */
110 Message(M_INFO,"udp (port %d): sending NAK\n",st->port);
111 buffer_init(st->rbuf,0);
112 buf_append_uint32(st->rbuf,dest);
113 buf_append_uint32(st->rbuf,source);
114 buf_append_uint32(st->rbuf,0); /* NAK is msg type 0 */
115 sendto(st->fd, st->rbuf->start, st->rbuf->size, 0,
116 (struct sockaddr *)&from, sizeof(from));
119 BUF_ASSERT_FREE(st->rbuf);
127 static void request_notify(void *commst, void *nst, comm_notify_fn *fn)
129 struct udp *st=commst;
130 struct notify_list *n;
132 n=safe_malloc(sizeof(*n),"request_notify");
139 static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
141 struct udp *st=commst;
142 struct notify_list *n, **p, *t;
146 for (n=st->notify; n; )
148 if (n->state==nst && n->fn==fn) {
160 static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
161 struct sockaddr_in *dest)
163 struct udp *st=commst;
168 memcpy(sa,&dest->sin_addr,4);
170 memcpy(sa+6,&dest->sin_port,2);
171 sendto(st->fd,sa,buf->size+8,0,(struct sockaddr *)&st->proxy,
174 sendto(st->fd, buf->start, buf->size, 0,
175 (struct sockaddr *)dest, sizeof(*dest));
181 static void udp_phase_hook(void *sst, uint32_t new_phase)
184 struct sockaddr_in addr;
186 st->fd=socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
188 fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line);
190 if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)|O_NONBLOCK)==-1) {
191 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
192 st->loc.file,st->loc.line);
194 if (fcntl(st->fd, F_SETFD, FD_CLOEXEC)==-1) {
195 fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)",
196 st->loc.file,st->loc.line);
199 memset(&addr, 0, sizeof(addr));
200 addr.sin_family=AF_INET;
201 addr.sin_addr.s_addr=htonl(st->addr);
202 addr.sin_port=htons(st->port);
207 /* XXX this fork() and waitpid() business needs to be hidden
208 in some system-specific library functions. */
211 fatal_perror("udp_phase_hook: fork() for authbind");
214 char *argv[4], addrstr[9], portstr[5];
215 sprintf(addrstr,"%08lX",(long)st->addr);
216 sprintf(portstr,"%04X",st->port);
217 argv[0]=st->authbind;
222 execvp(st->authbind,argv);
225 while (waitpid(c,&status,0)==-1) {
226 if (errno==EINTR) continue;
227 fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line);
229 if (WIFSIGNALED(status)) {
230 fatal("udp (%s:%d): authbind died on signal %d",st->loc.file,
231 st->loc.line, WTERMSIG(status));
233 if (WIFEXITED(status) && WEXITSTATUS(status)!=0) {
234 fatal("udp (%s:%d): authbind died with status %d",st->loc.file,
235 st->loc.line, WEXITSTATUS(status));
238 if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) {
239 fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
243 register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
246 static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
255 st=safe_malloc(sizeof(*st),"udp_apply(st)");
257 st->cl.description="udp";
260 st->cl.interface=&st->ops;
262 st->ops.min_start_pad=0;
263 st->ops.min_end_pad=0;
264 st->ops.request_notify=request_notify;
265 st->ops.release_notify=release_notify;
266 st->ops.sendmsg=udp_sendmsg;
271 if (!i || i->type!=t_dict) {
272 cfgfatal(st->loc,"udp","first argument must be a dictionary\n");
276 j=dict_find_item(d,"address",False,"udp",st->loc);
277 st->addr=j?st->addr=string_item_to_ipaddr(j, "udp"):INADDR_ANY;
278 st->port=dict_read_number(d,"port",True,"udp",st->loc,0);
279 st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc);
280 st->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
281 l=dict_lookup(d,"proxy");
284 memset(&st->proxy,0,sizeof(st->proxy));
285 st->proxy.sin_family=AF_INET;
287 if (!i || i->type!=t_string) {
288 cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
290 a=string_item_to_ipaddr(i,"proxy");
291 st->proxy.sin_addr.s_addr=htonl(a);
293 if (!i || i->type!=t_number) {
294 cfgfatal(st->loc,"udp","proxy must supply ""addr"",port\n");
296 st->proxy.sin_port=htons(i->data.number);
297 st->ops.min_start_pad=8;
300 add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
302 return new_closure(&st->cl);
305 init_module udp_module;
306 void udp_module(dict_t *dict)
308 add_closure(dict,"udp",udp_apply);