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
;
39 #define MAX_SOCKETS 3 /* 2 ought to do really */
51 struct udpsock socks
[MAX_SOCKETS
];
53 struct buffer_if
*rbuf
;
54 struct notify_list
*notify
;
60 * Re comm_addr.ix: This field allows us to note in the comm_addr
61 * which socket an incoming packet was received on. This is required
62 * for conveniently logging the actual source of a packet. But the ix
63 * does not formally form part of the address: it is not used when
64 * sending, nor when comparing two comm_addrs.
66 * The special value -1 means that the comm_addr was constructed by
67 * another module in secnet (eg the resolver), rather than being a
68 * description of the source of an incoming packet.
71 static const char *addr_to_string(void *commst
, const struct comm_addr
*ca
) {
72 struct udp
*st
=commst
;
73 static char sbuf
[100];
74 int ix
=ca
->ix
>=0 ? ca
->ix
: 0;
76 assert(ix
>=0 && ix
<st
->n_socks
);
77 snprintf(sbuf
, sizeof(sbuf
), "udp:%s%s-%s",
78 iaddr_to_string(&st
->socks
[ix
].addr
),
80 iaddr_to_string(&ca
->ia
));
84 static int udp_beforepoll(void *state
, struct pollfd
*fds
, int *nfds_io
,
89 if (*nfds_io
<st
->n_socks
) {
94 for (i
=0; i
<st
->n_socks
; i
++) {
95 fds
[i
].fd
=st
->socks
[i
].fd
;
101 static void udp_afterpoll(void *state
, struct pollfd
*fds
, int nfds
)
103 struct udp
*st
=state
;
106 struct notify_list
*n
;
111 for (i
=0; i
<st
->n_socks
; i
++) {
112 if (i
>=nfds
) continue;
113 if (!(fds
[i
].revents
& POLLIN
)) continue;
114 assert(fds
[i
].fd
== st
->socks
[i
].fd
);
115 int fd
=st
->socks
[i
].fd
;
117 fromlen
=sizeof(from
);
118 BUF_ASSERT_FREE(st
->rbuf
);
119 BUF_ALLOC(st
->rbuf
,"udp_afterpoll");
120 buffer_init(st
->rbuf
,calculate_max_start_pad());
121 rv
=recvfrom(fd
, st
->rbuf
->start
,
122 buf_remaining_space(st
->rbuf
),
123 0, &from
.sa
, &fromlen
);
127 /* Check that the packet came from our poxy server;
128 we shouldn't be contacted directly by anybody else
129 (since they can trivially forge source addresses) */
130 if (!iaddr_equal(&from
,&st
->proxy
)) {
131 Message(M_INFO
,"udp: received packet that's not "
136 /* proxy protocol supports ipv4 transport only */
137 from
.sa
.sa_family
=AF_INET
;
138 memcpy(&from
.sin
.sin_addr
,buf_unprepend(st
->rbuf
,4),4);
139 buf_unprepend(st
->rbuf
,2);
140 memcpy(&from
.sin
.sin_port
,buf_unprepend(st
->rbuf
,2),2);
147 for (n
=st
->notify
; n
; n
=n
->next
) {
148 if (n
->fn(n
->state
, st
->rbuf
, &ca
)) {
155 if (st
->rbuf
->size
>12 /* prevents traffic amplification */
156 && ((msgtype
=get_uint32(st
->rbuf
->start
+8))
158 uint32_t source
,dest
;
159 /* Manufacture and send NAK packet */
160 source
=get_uint32(st
->rbuf
->start
); /* Us */
161 dest
=get_uint32(st
->rbuf
->start
+4); /* Them */
162 send_nak(&ca
,source
,dest
,msgtype
,st
->rbuf
,"unwanted");
166 BUF_ASSERT_FREE(st
->rbuf
);
174 static void request_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
176 struct udp
*st
=commst
;
177 struct notify_list
*n
;
179 n
=safe_malloc(sizeof(*n
),"request_notify");
186 static void release_notify(void *commst
, void *nst
, comm_notify_fn
*fn
)
188 struct udp
*st
=commst
;
189 struct notify_list
*n
, **p
, *t
;
193 for (n
=st
->notify
; n
; )
195 if (n
->state
==nst
&& n
->fn
==fn
) {
207 static bool_t
udp_sendmsg(void *commst
, struct buffer_if
*buf
,
208 const struct comm_addr
*dest
)
210 struct udp
*st
=commst
;
214 sa
=buf_prepend(buf
,8);
215 if (dest
->ia
.sa
.sa_family
!= AF_INET
) {
217 "udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
218 iaddr_to_string(&dest
->ia
));
221 memcpy(sa
,&dest
->ia
.sin
.sin_addr
,4);
223 memcpy(sa
+6,&dest
->ia
.sin
.sin_port
,2);
224 sendto(st
->socks
[0].fd
,sa
,buf
->size
+8,0,&st
->proxy
.sa
,
225 iaddr_socklen(&st
->proxy
));
226 buf_unprepend(buf
,8);
229 bool_t allunsupported
=True
;
230 for (i
=0; i
<st
->n_socks
; i
++) {
231 if (dest
->ia
.sa
.sa_family
!= st
->socks
[i
].addr
.sa
.sa_family
)
232 /* no point even trying */
234 r
=sendto(st
->socks
[i
].fd
, buf
->start
, buf
->size
, 0,
235 &dest
->ia
.sa
, iaddr_socklen(&dest
->ia
));
236 if (r
>=0) return True
;
237 if (!(errno
==EAFNOSUPPORT
|| errno
==ENETUNREACH
))
238 /* who knows what that error means? */
239 allunsupported
=False
;
241 return !allunsupported
; /* see doc for comm_sendmsg_fn in secnet.h */
247 static void udp_make_socket(struct udp
*st
, struct udpsock
*us
)
249 const union iaddr
*addr
=&us
->addr
;
250 us
->fd
=socket(addr
->sa
.sa_family
, SOCK_DGRAM
, IPPROTO_UDP
);
252 fatal_perror("udp (%s:%d): socket",st
->loc
.file
,st
->loc
.line
);
254 if (fcntl(us
->fd
, F_SETFL
, fcntl(us
->fd
, F_GETFL
)|O_NONBLOCK
)==-1) {
255 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
256 st
->loc
.file
,st
->loc
.line
);
260 if (addr
->sa
.sa_family
==AF_INET6
) {
263 socklen_t optlen
=sizeof(optval
);
264 r
=setsockopt(us
->fd
,IPPROTO_IPV6
,IPV6_V6ONLY
,&optval
,optlen
);
265 if (r
) fatal_perror("udp (%s:%d): setsockopt(,IPV6_V6ONLY,&1,)",
266 st
->loc
.file
,st
->loc
.line
);
274 /* XXX this fork() and waitpid() business needs to be hidden
275 in some system-specific library functions. */
278 fatal_perror("udp_phase_hook: fork() for authbind");
281 char *argv
[5], addrstr
[33], portstr
[5];
284 switch (addr
->sa
.sa_family
) {
286 sprintf(addrstr
,"%08lX",(long)addr
->sin
.sin_addr
.s_addr
);
287 port
=addr
->sin
.sin_port
;
294 sprintf(addrstr
+i
*2,"%02X",addr
->sin6
.sin6_addr
.s6_addr
[i
]);
295 port
=addr
->sin6
.sin6_port
;
299 #endif /*CONFIG_IPV6*/
301 fatal("udp (%s:%d): unsupported address family for authbind",
302 st
->loc
.file
,st
->loc
.line
);
304 sprintf(portstr
,"%04X",port
);
305 argv
[0]=st
->authbind
;
308 argv
[3]=(char*)addrfam
;
311 execvp(st
->authbind
,argv
);
314 while (waitpid(c
,&status
,0)==-1) {
315 if (errno
==EINTR
) continue;
316 fatal_perror("udp (%s:%d): authbind",st
->loc
.file
,st
->loc
.line
);
318 if (WIFSIGNALED(status
)) {
319 fatal("udp (%s:%d): authbind died on signal %d",st
->loc
.file
,
320 st
->loc
.line
, WTERMSIG(status
));
322 if (WIFEXITED(status
) && WEXITSTATUS(status
)!=0) {
323 fatal("udp (%s:%d): authbind died with status %d",st
->loc
.file
,
324 st
->loc
.line
, WEXITSTATUS(status
));
327 if (bind(us
->fd
, &addr
->sa
, iaddr_socklen(addr
))!=0) {
328 fatal_perror("udp (%s:%d): bind",st
->loc
.file
,st
->loc
.line
);
333 static void udp_phase_hook(void *sst
, uint32_t new_phase
)
337 for (i
=0; i
<st
->n_socks
; i
++)
338 udp_make_socket(st
,&st
->socks
[i
]);
340 register_for_poll(st
,udp_beforepoll
,udp_afterpoll
,MAX_SOCKETS
,"udp");
343 static list_t
*udp_apply(closure_t
*self
, struct cloc loc
, dict_t
*context
,
354 st
=safe_malloc(sizeof(*st
),"udp_apply(st)");
356 st
->cl
.description
="udp";
359 st
->cl
.interface
=&st
->ops
;
361 st
->ops
.request_notify
=request_notify
;
362 st
->ops
.release_notify
=release_notify
;
363 st
->ops
.sendmsg
=udp_sendmsg
;
364 st
->ops
.addr_to_string
=addr_to_string
;
367 item
=list_elem(args
,0);
368 if (!item
|| item
->type
!=t_dict
) {
369 cfgfatal(st
->loc
,"udp","first argument must be a dictionary\n");
373 int port
=dict_read_number(d
,"port",True
,"udp",st
->loc
,0);
375 union iaddr defaultaddrs
[] = {
377 { .sin6
= { .sin6_family
=AF_INET6
,
378 .sin6_port
=htons(port
),
379 .sin6_addr
=IN6ADDR_ANY_INIT
} },
381 { .sin
= { .sin_family
=AF_INET
,
382 .sin_port
=htons(port
),
383 .sin_addr
= { .s_addr
=INADDR_ANY
} } }
386 caddrl
=dict_lookup(d
,"address");
387 st
->n_socks
=caddrl ?
list_length(caddrl
) : (int)ARRAY_SIZE(defaultaddrs
);
388 if (st
->n_socks
<=0 || st
->n_socks
>MAX_SOCKETS
)
389 cfgfatal(st
->loc
,"udp","`address' must be 1..%d addresses",
392 for (i
=0; i
<st
->n_socks
; i
++) {
393 struct udpsock
*us
=&st
->socks
[i
];
394 if (!list_length(caddrl
)) {
395 us
->addr
=defaultaddrs
[i
];
397 string_item_to_iaddr(list_elem(caddrl
,i
),port
,&us
->addr
,"udp");
402 st
->rbuf
=find_cl_if(d
,"buffer",CL_BUFFER
,True
,"udp",st
->loc
);
403 st
->authbind
=dict_read_string(d
,"authbind",False
,"udp",st
->loc
);
404 l
=dict_lookup(d
,"proxy");
407 st
->proxy
.sa
.sa_family
=AF_INET
;
409 if (!item
|| item
->type
!=t_string
) {
410 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
412 a
=string_item_to_ipaddr(item
,"proxy");
413 st
->proxy
.sin
.sin_addr
.s_addr
=htonl(a
);
415 if (!item
|| item
->type
!=t_number
) {
416 cfgfatal(st
->loc
,"udp","proxy must supply ""addr"",port\n");
418 st
->proxy
.sin
.sin_port
=htons(item
->data
.number
);
421 update_max_start_pad(&comm_max_start_pad
, st
->use_proxy ?
8 : 0);
423 add_hook(PHASE_GETRESOURCES
,udp_phase_hook
,st
);
425 return new_closure(&st
->cl
);
428 void udp_module(dict_t
*dict
)
430 add_closure(dict
,"udp",udp_apply
);