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
;
42 struct buffer_if
*rbuf
;
43 struct notify_list
*notify
;
45 struct sockaddr_in proxy
;
48 static int udp_beforepoll(void *state
, struct pollfd
*fds
, int *nfds_io
,
49 int *timeout_io
, const struct timeval
*tv
,
63 static void udp_afterpoll(void *state
, struct pollfd
*fds
, int nfds
,
64 const struct timeval
*tv
, uint64_t *now
)
67 struct sockaddr_in from
;
69 struct notify_list
*n
;
73 if (nfds
&& (fds
->revents
& POLLIN
)) {
76 BUF_ASSERT_FREE(st
->rbuf
);
77 BUF_ALLOC(st
->rbuf
,"udp_afterpoll");
78 rv
=recvfrom(st
->fd
, st
->rbuf
->start
, st
->rbuf
->len
, 0,
79 (struct sockaddr
*)&from
, &fromlen
);
83 /* Check that the packet came from our poxy server;
84 we shouldn't be contacted directly by anybody else
85 (since they can trivially forge source addresses) */
86 if (memcmp(&from
.sin_addr
,&st
->proxy
.sin_addr
,4)!=0 ||
87 memcmp(&from
.sin_port
,&st
->proxy
.sin_port
,2)!=0) {
88 Message(M_INFO
,"udp: received packet that's not "
93 memcpy(&from
.sin_addr
,buf_unprepend(st
->rbuf
,4),4);
94 buf_unprepend(st
->rbuf
,2);
95 memcpy(&from
.sin_port
,buf_unprepend(st
->rbuf
,2),2);
98 for (n
=st
->notify
; n
; n
=n
->next
) {
99 if (n
->fn(n
->state
, st
->rbuf
, &from
)) {
105 uint32_t source
,dest
;
106 /* Manufacture and send NAK packet */
107 source
=get_uint32(st
->rbuf
->start
); /* Us */
108 dest
=get_uint32(st
->rbuf
->start
+4); /* Them */
109 Message(M_INFO
,"udp (port %d): sending NAK\n",st
->port
);
110 buffer_init(st
->rbuf
,0);
111 buf_append_uint32(st
->rbuf
,dest
);
112 buf_append_uint32(st
->rbuf
,source
);
113 buf_append_uint32(st
->rbuf
,0); /* NAK is msg type 0 */
114 sendto(st
->fd
, st
->rbuf
->start
, st
->rbuf
->size
, 0,
115 (struct sockaddr
*)&from
, sizeof(from
));
118 BUF_ASSERT_FREE(st
->rbuf
);
126 static void request_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
128 struct udp
*st
=commst
;
129 struct notify_list
*n
;
131 n
=safe_malloc(sizeof(*n
),"request_notify");
138 static void release_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
140 struct udp
*st
=commst
;
141 struct notify_list
*n
, **p
, *t
;
145 for (n
=st
->notify
; n
; )
147 if (n
->state
==nst
&& n
->fn
==fn
) {
159 static bool_t
udp_sendmsg(void *commst
, struct buffer_if
*buf
,
160 struct sockaddr_in
*dest
)
162 struct udp
*st
=commst
;
167 memcpy(sa
,&dest
->sin_addr
,4);
169 memcpy(sa
+6,&dest
->sin_port
,2);
170 sendto(st
->fd
,sa
,buf
->size
+8,0,(struct sockaddr
*)&st
->proxy
,
173 sendto(st
->fd
, buf
->start
, buf
->size
, 0,
174 (struct sockaddr
*)dest
, sizeof(*dest
));
180 static void udp_phase_hook(void *sst
, uint32_t new_phase
)
183 struct sockaddr_in addr
;
185 st
->fd
=socket(AF_INET
, SOCK_DGRAM
, 0);
187 fatal_perror("udp (%s:%d): socket",st
->loc
.file
,st
->loc
.line
);
189 if (fcntl(st
->fd
, F_SETFL
, fcntl(st
->fd
, F_GETFL
)|O_NONBLOCK
)==-1) {
190 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
191 st
->loc
.file
,st
->loc
.line
);
193 if (fcntl(st
->fd
, F_SETFD
, FD_CLOEXEC
)==-1) {
194 fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)",
195 st
->loc
.file
,st
->loc
.line
);
198 memset(&addr
, 0, sizeof(addr
));
199 addr
.sin_family
=AF_INET
;
200 addr
.sin_port
=htons(st
->port
);
205 /* XXX this fork() and waitpid() business needs to be hidden
206 in some system-specific library functions. */
209 fatal_perror("udp_phase_hook: fork() for authbind");
213 argv
[0]=st
->authbind
;
216 if (!argv
[2]) exit(ENOMEM
);
217 sprintf(argv
[2],"%04X",htons(st
->port
));
220 execvp(st
->authbind
,argv
);
223 waitpid(c
,&status
,0);
224 if (WEXITSTATUS(status
)!=0) {
225 errno
=WEXITSTATUS(status
);
226 fatal_perror("udp (%s:%d): authbind",st
->loc
.file
,st
->loc
.line
);
229 if (bind(st
->fd
, (struct sockaddr
*)&addr
, sizeof(addr
))!=0) {
230 fatal_perror("udp (%s:%d): bind",st
->loc
.file
,st
->loc
.line
);
234 register_for_poll(st
,udp_beforepoll
,udp_afterpoll
,1,"udp");
237 static list_t
*udp_apply(closure_t
*self
, struct cloc loc
, dict_t
*context
,
246 st
=safe_malloc(sizeof(*st
),"udp_apply(st)");
248 st
->cl
.description
="udp";
251 st
->cl
.interface
=&st
->ops
;
253 st
->ops
.min_start_pad
=0;
254 st
->ops
.min_end_pad
=0;
255 st
->ops
.request_notify
=request_notify
;
256 st
->ops
.release_notify
=release_notify
;
257 st
->ops
.sendmsg
=udp_sendmsg
;
262 if (!i
|| i
->type
!=t_dict
) {
263 cfgfatal(st
->loc
,"udp","first argument must be a dictionary\n");
267 st
->port
=dict_read_number(d
,"port",True
,"udp",st
->loc
,0);
268 st
->rbuf
=find_cl_if(d
,"buffer",CL_BUFFER
,True
,"udp",st
->loc
);
269 st
->authbind
=dict_read_string(d
,"authbind",False
,"udp",st
->loc
);
270 l
=dict_lookup(d
,"proxy");
273 memset(&st
->proxy
,0,sizeof(st
->proxy
));
274 st
->proxy
.sin_family
=AF_INET
;
276 if (!i
|| i
->type
!=t_string
) {
277 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
279 a
=string_item_to_ipaddr(i
,"proxy");
280 st
->proxy
.sin_addr
.s_addr
=htonl(a
);
282 if (!i
|| i
->type
!=t_number
) {
283 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
285 st
->proxy
.sin_port
=htons(i
->data
.number
);
286 st
->ops
.min_start_pad
=8;
289 add_hook(PHASE_GETRESOURCES
,udp_phase_hook
,st
);
291 return new_closure(&st
->cl
);
294 init_module udp_module
;
295 void udp_module(dict_t
*dict
)
297 add_closure(dict
,"udp",udp_apply
);