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 * Sites register an interest in local port numbers for receiving
9 * packets, and can also send packets. We don't care about the source
10 * port number for sending packets.
12 * Packets are offered to registered receivers in turn. Once one
13 * accepts it, it isn't offered to any more. */
21 #include <sys/socket.h>
24 #include "unaligned.h"
26 static beforepoll_fn udp_beforepoll;
27 static afterpoll_fn udp_afterpoll;
28 static comm_request_notify_fn request_notify;
29 static comm_release_notify_fn release_notify;
30 static comm_sendmsg_fn udp_sendmsg;
32 /* The UDP module exports a pure closure which can be used to construct a
33 * UDP send/receive module. Arguments:
39 struct notify_list *next;
49 struct buffer_if *rbuf;
50 struct notify_list *notify;
53 static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
54 int *timeout_io, const struct timeval *tv,
68 static void udp_afterpoll(void *state, struct pollfd *fds, int nfds,
69 const struct timeval *tv, uint64_t *now)
72 struct sockaddr_in from;
74 struct notify_list *n;
78 if (nfds && (fds->revents & POLLIN)) {
81 BUF_ASSERT_FREE(st->rbuf);
82 BUF_ALLOC(st->rbuf,"udp_afterpoll");
83 rv=recvfrom(st->fd, st->rbuf->start, st->rbuf->len, 0,
84 (struct sockaddr *)&from, &fromlen);
88 for (n=st->notify; n; n=n->next) {
89 if (n->fn(n->state, st->rbuf, &from)) {
96 /* XXX manufacture and send NAK packet */
97 source=get_uint32(st->rbuf->start); /* Us */
98 dest=get_uint32(st->rbuf->start+4); /* Them */
99 Message(M_INFO,"udp (port %d): sending NAK\n",st->port);
100 buffer_init(st->rbuf,0);
101 buf_append_uint32(st->rbuf,dest);
102 buf_append_uint32(st->rbuf,source);
103 buf_append_uint32(st->rbuf,0); /* NAK is msg type 0 */
104 sendto(st->fd, st->rbuf->start, st->rbuf->size, 0,
105 (struct sockaddr *)&from, sizeof(from));
108 BUF_ASSERT_FREE(st->rbuf);
116 static void request_notify(void *commst, void *nst, comm_notify_fn *fn)
118 struct udp *st=commst;
119 struct notify_list *n;
121 n=safe_malloc(sizeof(*n),"request_notify");
128 static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
130 struct udp *st=commst;
131 struct notify_list *n, **p, *t;
135 for (n=st->notify; n; )
137 if (n->state==nst && n->fn==fn) {
149 static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
150 struct sockaddr_in *dest)
152 struct udp *st=commst;
154 /* XXX fix error reporting */
155 sendto(st->fd, buf->start, buf->size, 0,
156 (struct sockaddr *)dest, sizeof(*dest));
161 static void udp_phase_hook(void *sst, uint32_t new_phase)
164 struct sockaddr_in addr;
166 st->fd=socket(AF_INET, SOCK_DGRAM, 0);
168 fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line);
170 if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)|O_NONBLOCK)==-1) {
171 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
172 st->loc.file,st->loc.line);
174 if (fcntl(st->fd, F_SETFD, FD_CLOEXEC)==-1) {
175 fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)",
176 st->loc.file,st->loc.line);
179 memset(&addr, 0, sizeof(addr));
180 addr.sin_family=AF_INET;
181 addr.sin_port=htons(st->port);
186 /* XXX this fork() and waitpid() business needs to be hidden
187 in some system-specific library functions. */
190 fatal_perror("udp_phase_hook: fork() for authbind");
194 argv[0]=st->authbind;
197 if (!argv[2]) exit(ENOMEM);
198 sprintf(argv[2],"%04X",htons(st->port));
201 execvp(st->authbind,argv);
204 waitpid(c,&status,0);
205 if (WEXITSTATUS(status)!=0) {
206 errno=WEXITSTATUS(status);
207 fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line);
210 if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) {
211 fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
215 register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
218 static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
225 st=safe_malloc(sizeof(*st),"udp_apply(st)");
227 st->cl.description="udp";
230 st->cl.interface=&st->ops;
232 st->ops.request_notify=request_notify;
233 st->ops.release_notify=release_notify;
234 st->ops.sendmsg=udp_sendmsg;
238 if (!i || i->type!=t_dict) {
239 cfgfatal(st->loc,"udp","first argument must be a dictionary\n");
243 st->port=dict_read_number(d,"port",True,"udp",st->loc,0);
244 st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc);
245 st->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
247 add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
249 return new_closure(&st->cl);
252 init_module udp_module;
253 void udp_module(dict_t *dict)
255 add_closure(dict,"udp",udp_apply);