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>
22 #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
;
35 struct notify_list
*next
;
46 struct buffer_if
*rbuf
;
47 struct notify_list
*notify
;
49 struct sockaddr_in proxy
;
52 static const char *saddr_to_string(const struct sockaddr_in
*sin
) {
53 static char bufs
[2][100];
57 snprintf(bufs
[b
], sizeof(bufs
[b
]), "[%s]:%d",
58 inet_ntoa(sin
->sin_addr
),
59 ntohs(sin
->sin_port
));
63 static const char *addr_to_string(void *commst
, const struct comm_addr
*ca
) {
64 struct udp
*st
=commst
;
65 static char sbuf
[100];
67 struct sockaddr_in la
;
68 la
.sin_addr
.s_addr
=htonl(st
->addr
);
69 la
.sin_port
=htons(st
->port
);
71 snprintf(sbuf
, sizeof(sbuf
), "udp:%s-%s",
72 saddr_to_string(&la
), saddr_to_string(&ca
->sin
));
76 static int udp_beforepoll(void *state
, struct pollfd
*fds
, int *nfds_io
,
90 static void udp_afterpoll(void *state
, struct pollfd
*fds
, int nfds
)
93 struct sockaddr_in from
;
95 struct notify_list
*n
;
99 if (nfds
&& (fds
->revents
& POLLIN
)) {
102 fromlen
=sizeof(from
);
103 BUF_ASSERT_FREE(st
->rbuf
);
104 BUF_ALLOC(st
->rbuf
,"udp_afterpoll");
105 rv
=recvfrom(st
->fd
, st
->rbuf
->start
, st
->rbuf
->len
, 0,
106 (struct sockaddr
*)&from
, &fromlen
);
110 /* Check that the packet came from our poxy server;
111 we shouldn't be contacted directly by anybody else
112 (since they can trivially forge source addresses) */
113 if (memcmp(&from
.sin_addr
,&st
->proxy
.sin_addr
,4)!=0 ||
114 memcmp(&from
.sin_port
,&st
->proxy
.sin_port
,2)!=0) {
115 Message(M_INFO
,"udp: received packet that's not "
120 memcpy(&from
.sin_addr
,buf_unprepend(st
->rbuf
,4),4);
121 buf_unprepend(st
->rbuf
,2);
122 memcpy(&from
.sin_port
,buf_unprepend(st
->rbuf
,2),2);
125 for (n
=st
->notify
; n
; n
=n
->next
) {
130 if (n
->fn(n
->state
, st
->rbuf
, &ca
)) {
137 if (st
->rbuf
->size
>12 /* prevents traffic amplification */
138 && ((msgtype
=get_uint32(st
->rbuf
->start
+8))
140 uint32_t source
,dest
;
141 /* Manufacture and send NAK packet */
142 source
=get_uint32(st
->rbuf
->start
); /* Us */
143 dest
=get_uint32(st
->rbuf
->start
+4); /* Them */
144 Message(M_INFO
,"udp (port %d, peer %s):"
145 " %08"PRIx32
"<-%08"PRIx32
": %08"PRIx32
":"
146 " unwanted/incorrect, sending NAK\n",
147 st
->port
, saddr_to_string(&from
),
148 dest
, source
, msgtype
);
149 buffer_init(st
->rbuf
,0);
150 buf_append_uint32(st
->rbuf
,dest
);
151 buf_append_uint32(st
->rbuf
,source
);
152 buf_append_uint32(st
->rbuf
,LABEL_NAK
);
153 sendto(st
->fd
, st
->rbuf
->start
, st
->rbuf
->size
, 0,
154 (struct sockaddr
*)&from
, sizeof(from
));
158 BUF_ASSERT_FREE(st
->rbuf
);
166 static void request_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
168 struct udp
*st
=commst
;
169 struct notify_list
*n
;
171 n
=safe_malloc(sizeof(*n
),"request_notify");
178 static void release_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
180 struct udp
*st
=commst
;
181 struct notify_list
*n
, **p
, *t
;
185 for (n
=st
->notify
; n
; )
187 if (n
->state
==nst
&& n
->fn
==fn
) {
199 static bool_t
udp_sendmsg(void *commst
, struct buffer_if
*buf
,
200 const struct comm_addr
*dest
)
202 struct udp
*st
=commst
;
207 memcpy(sa
,&dest
->sin
.sin_addr
,4);
209 memcpy(sa
+6,&dest
->sin
.sin_port
,2);
210 sendto(st
->fd
,sa
,buf
->size
+8,0,(struct sockaddr
*)&st
->proxy
,
213 sendto(st
->fd
, buf
->start
, buf
->size
, 0,
214 (struct sockaddr
*)&dest
->sin
, sizeof(dest
->sin
));
220 static void udp_phase_hook(void *sst
, uint32_t new_phase
)
223 struct sockaddr_in addr
;
225 st
->fd
=socket(PF_INET
, SOCK_DGRAM
, IPPROTO_UDP
);
227 fatal_perror("udp (%s:%d): socket",st
->loc
.file
,st
->loc
.line
);
229 if (fcntl(st
->fd
, F_SETFL
, fcntl(st
->fd
, F_GETFL
)|O_NONBLOCK
)==-1) {
230 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
231 st
->loc
.file
,st
->loc
.line
);
233 if (fcntl(st
->fd
, F_SETFD
, FD_CLOEXEC
)==-1) {
234 fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)",
235 st
->loc
.file
,st
->loc
.line
);
239 addr
.sin_family
=AF_INET
;
240 addr
.sin_addr
.s_addr
=htonl(st
->addr
);
241 addr
.sin_port
=htons(st
->port
);
246 /* XXX this fork() and waitpid() business needs to be hidden
247 in some system-specific library functions. */
250 fatal_perror("udp_phase_hook: fork() for authbind");
253 char *argv
[4], addrstr
[9], portstr
[5];
254 sprintf(addrstr
,"%08lX",(long)addr
.sin_addr
.s_addr
);
255 sprintf(portstr
,"%04X",addr
.sin_port
);
256 argv
[0]=st
->authbind
;
261 execvp(st
->authbind
,argv
);
264 while (waitpid(c
,&status
,0)==-1) {
265 if (errno
==EINTR
) continue;
266 fatal_perror("udp (%s:%d): authbind",st
->loc
.file
,st
->loc
.line
);
268 if (WIFSIGNALED(status
)) {
269 fatal("udp (%s:%d): authbind died on signal %d",st
->loc
.file
,
270 st
->loc
.line
, WTERMSIG(status
));
272 if (WIFEXITED(status
) && WEXITSTATUS(status
)!=0) {
273 fatal("udp (%s:%d): authbind died with status %d",st
->loc
.file
,
274 st
->loc
.line
, WEXITSTATUS(status
));
277 if (bind(st
->fd
, (struct sockaddr
*)&addr
, sizeof(addr
))!=0) {
278 fatal_perror("udp (%s:%d): bind",st
->loc
.file
,st
->loc
.line
);
282 register_for_poll(st
,udp_beforepoll
,udp_afterpoll
,1,"udp");
285 static list_t
*udp_apply(closure_t
*self
, struct cloc loc
, dict_t
*context
,
294 st
=safe_malloc(sizeof(*st
),"udp_apply(st)");
296 st
->cl
.description
="udp";
299 st
->cl
.interface
=&st
->ops
;
301 st
->ops
.min_start_pad
=0;
302 st
->ops
.min_end_pad
=0;
303 st
->ops
.request_notify
=request_notify
;
304 st
->ops
.release_notify
=release_notify
;
305 st
->ops
.sendmsg
=udp_sendmsg
;
306 st
->ops
.addr_to_string
=addr_to_string
;
311 if (!i
|| i
->type
!=t_dict
) {
312 cfgfatal(st
->loc
,"udp","first argument must be a dictionary\n");
316 j
=dict_find_item(d
,"address",False
,"udp",st
->loc
);
317 st
->addr
=j?
string_item_to_ipaddr(j
, "udp"):INADDR_ANY
;
318 st
->port
=dict_read_number(d
,"port",True
,"udp",st
->loc
,0);
319 st
->rbuf
=find_cl_if(d
,"buffer",CL_BUFFER
,True
,"udp",st
->loc
);
320 st
->authbind
=dict_read_string(d
,"authbind",False
,"udp",st
->loc
);
321 l
=dict_lookup(d
,"proxy");
325 st
->proxy
.sin_family
=AF_INET
;
327 if (!i
|| i
->type
!=t_string
) {
328 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
330 a
=string_item_to_ipaddr(i
,"proxy");
331 st
->proxy
.sin_addr
.s_addr
=htonl(a
);
333 if (!i
|| i
->type
!=t_number
) {
334 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
336 st
->proxy
.sin_port
=htons(i
->data
.number
);
337 st
->ops
.min_start_pad
=8;
340 add_hook(PHASE_GETRESOURCES
,udp_phase_hook
,st
);
342 return new_closure(&st
->cl
);
345 void udp_module(dict_t
*dict
)
347 add_closure(dict
,"udp",udp_apply
);