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
;
47 struct buffer_if
*rbuf
;
48 struct notify_list
*notify
;
50 struct sockaddr_in proxy
;
53 static const char *saddr_to_string(const struct sockaddr_in
*sin
) {
54 static char bufs
[2][100];
58 snprintf(bufs
[b
], sizeof(bufs
[b
]), "[%s]:%d",
59 inet_ntoa(sin
->sin_addr
),
60 ntohs(sin
->sin_port
));
64 static const char *addr_to_string(void *commst
, const struct comm_addr
*ca
) {
65 struct udp
*st
=commst
;
66 static char sbuf
[100];
68 struct sockaddr_in la
;
69 la
.sin_addr
.s_addr
=htonl(st
->addr
);
70 la
.sin_port
=htons(st
->port
);
72 snprintf(sbuf
, sizeof(sbuf
), "udp:%s-%s",
73 saddr_to_string(&la
), saddr_to_string(&ca
->sin
));
77 static int udp_beforepoll(void *state
, struct pollfd
*fds
, int *nfds_io
,
91 static void udp_afterpoll(void *state
, struct pollfd
*fds
, int nfds
)
94 struct sockaddr_in from
;
96 struct notify_list
*n
;
100 if (nfds
&& (fds
->revents
& POLLIN
)) {
103 fromlen
=sizeof(from
);
104 BUF_ASSERT_FREE(st
->rbuf
);
105 BUF_ALLOC(st
->rbuf
,"udp_afterpoll");
106 buffer_init(st
->rbuf
,calculate_max_start_pad());
107 rv
=recvfrom(st
->fd
, st
->rbuf
->start
,
108 buf_remaining_space(st
->rbuf
),
109 0, (struct sockaddr
*)&from
, &fromlen
);
113 /* Check that the packet came from our poxy server;
114 we shouldn't be contacted directly by anybody else
115 (since they can trivially forge source addresses) */
116 if (memcmp(&from
.sin_addr
,&st
->proxy
.sin_addr
,4)!=0 ||
117 memcmp(&from
.sin_port
,&st
->proxy
.sin_port
,2)!=0) {
118 Message(M_INFO
,"udp: received packet that's not "
123 memcpy(&from
.sin_addr
,buf_unprepend(st
->rbuf
,4),4);
124 buf_unprepend(st
->rbuf
,2);
125 memcpy(&from
.sin_port
,buf_unprepend(st
->rbuf
,2),2);
132 for (n
=st
->notify
; n
; n
=n
->next
) {
133 if (n
->fn(n
->state
, st
->rbuf
, &ca
)) {
140 if (st
->rbuf
->size
>12 /* prevents traffic amplification */
141 && ((msgtype
=get_uint32(st
->rbuf
->start
+8))
143 uint32_t source
,dest
;
144 /* Manufacture and send NAK packet */
145 source
=get_uint32(st
->rbuf
->start
); /* Us */
146 dest
=get_uint32(st
->rbuf
->start
+4); /* Them */
147 send_nak(&ca
,source
,dest
,msgtype
,st
->rbuf
,"unwanted");
151 BUF_ASSERT_FREE(st
->rbuf
);
159 static void request_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
161 struct udp
*st
=commst
;
162 struct notify_list
*n
;
164 n
=safe_malloc(sizeof(*n
),"request_notify");
171 static void release_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
173 struct udp
*st
=commst
;
174 struct notify_list
*n
, **p
, *t
;
178 for (n
=st
->notify
; n
; )
180 if (n
->state
==nst
&& n
->fn
==fn
) {
192 static bool_t
udp_sendmsg(void *commst
, struct buffer_if
*buf
,
193 const struct comm_addr
*dest
)
195 struct udp
*st
=commst
;
199 sa
=buf_prepend(buf
,8);
200 memcpy(sa
,&dest
->sin
.sin_addr
,4);
202 memcpy(sa
+6,&dest
->sin
.sin_port
,2);
203 sendto(st
->fd
,sa
,buf
->size
+8,0,(struct sockaddr
*)&st
->proxy
,
205 buf_unprepend(buf
,8);
207 sendto(st
->fd
, buf
->start
, buf
->size
, 0,
208 (struct sockaddr
*)&dest
->sin
, sizeof(dest
->sin
));
214 static void udp_phase_hook(void *sst
, uint32_t new_phase
)
217 struct sockaddr_in addr
;
219 st
->fd
=socket(PF_INET
, SOCK_DGRAM
, IPPROTO_UDP
);
221 fatal_perror("udp (%s:%d): socket",st
->loc
.file
,st
->loc
.line
);
223 if (fcntl(st
->fd
, F_SETFL
, fcntl(st
->fd
, F_GETFL
)|O_NONBLOCK
)==-1) {
224 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
225 st
->loc
.file
,st
->loc
.line
);
230 addr
.sin_family
=AF_INET
;
231 addr
.sin_addr
.s_addr
=htonl(st
->addr
);
232 addr
.sin_port
=htons(st
->port
);
237 /* XXX this fork() and waitpid() business needs to be hidden
238 in some system-specific library functions. */
241 fatal_perror("udp_phase_hook: fork() for authbind");
244 char *argv
[4], addrstr
[9], portstr
[5];
245 sprintf(addrstr
,"%08lX",(long)addr
.sin_addr
.s_addr
);
246 sprintf(portstr
,"%04X",addr
.sin_port
);
247 argv
[0]=st
->authbind
;
252 execvp(st
->authbind
,argv
);
255 while (waitpid(c
,&status
,0)==-1) {
256 if (errno
==EINTR
) continue;
257 fatal_perror("udp (%s:%d): authbind",st
->loc
.file
,st
->loc
.line
);
259 if (WIFSIGNALED(status
)) {
260 fatal("udp (%s:%d): authbind died on signal %d",st
->loc
.file
,
261 st
->loc
.line
, WTERMSIG(status
));
263 if (WIFEXITED(status
) && WEXITSTATUS(status
)!=0) {
264 fatal("udp (%s:%d): authbind died with status %d",st
->loc
.file
,
265 st
->loc
.line
, WEXITSTATUS(status
));
268 if (bind(st
->fd
, (struct sockaddr
*)&addr
, sizeof(addr
))!=0) {
269 fatal_perror("udp (%s:%d): bind",st
->loc
.file
,st
->loc
.line
);
273 register_for_poll(st
,udp_beforepoll
,udp_afterpoll
,1,"udp");
276 static list_t
*udp_apply(closure_t
*self
, struct cloc loc
, dict_t
*context
,
285 st
=safe_malloc(sizeof(*st
),"udp_apply(st)");
287 st
->cl
.description
="udp";
290 st
->cl
.interface
=&st
->ops
;
292 st
->ops
.request_notify
=request_notify
;
293 st
->ops
.release_notify
=release_notify
;
294 st
->ops
.sendmsg
=udp_sendmsg
;
295 st
->ops
.addr_to_string
=addr_to_string
;
300 if (!i
|| i
->type
!=t_dict
) {
301 cfgfatal(st
->loc
,"udp","first argument must be a dictionary\n");
305 j
=dict_find_item(d
,"address",False
,"udp",st
->loc
);
306 st
->addr
=j?
string_item_to_ipaddr(j
, "udp"):INADDR_ANY
;
307 st
->port
=dict_read_number(d
,"port",True
,"udp",st
->loc
,0);
308 st
->rbuf
=find_cl_if(d
,"buffer",CL_BUFFER
,True
,"udp",st
->loc
);
309 st
->authbind
=dict_read_string(d
,"authbind",False
,"udp",st
->loc
);
310 l
=dict_lookup(d
,"proxy");
314 st
->proxy
.sin_family
=AF_INET
;
316 if (!i
|| i
->type
!=t_string
) {
317 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
319 a
=string_item_to_ipaddr(i
,"proxy");
320 st
->proxy
.sin_addr
.s_addr
=htonl(a
);
322 if (!i
|| i
->type
!=t_number
) {
323 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
325 st
->proxy
.sin_port
=htons(i
->data
.number
);
328 update_max_start_pad(&comm_max_start_pad
, st
->use_proxy ?
8 : 0);
330 add_hook(PHASE_GETRESOURCES
,udp_phase_hook
,st
);
332 return new_closure(&st
->cl
);
335 void udp_module(dict_t
*dict
)
337 add_closure(dict
,"udp",udp_apply
);