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"
26 #include "comm-common.h"
28 static comm_sendmsg_fn udp_sendmsg
;
32 struct udpsocks socks
;
36 * Re comm_addr.ix: This field allows us to note in the comm_addr
37 * which socket an incoming packet was received on. This is required
38 * for conveniently logging the actual source of a packet. But the ix
39 * does not formally form part of the address: it is not used when
40 * sending, nor when comparing two comm_addrs.
42 * The special value -1 means that the comm_addr was constructed by
43 * another module in secnet (eg the resolver), rather than being a
44 * description of the source of an incoming packet.
47 static const char *udp_addr_to_string(void *commst
, const struct comm_addr
*ca
)
49 struct udp
*st
=commst
;
50 struct udpsocks
*socks
=&st
->socks
;
51 static char sbuf
[100];
52 int ix
=ca
->ix
>=0 ? ca
->ix
: 0;
54 assert(ix
>=0 && ix
<socks
->n_socks
);
55 snprintf(sbuf
, sizeof(sbuf
), "udp:%s%s-%s",
56 iaddr_to_string(&socks
->socks
[ix
].addr
),
57 ca
->ix
<0 && socks
->n_socks
>1 ?
"&" : "",
58 iaddr_to_string(&ca
->ia
));
62 static int udp_socks_beforepoll(void *state
, struct pollfd
*fds
, int *nfds_io
,
65 struct udpsocks
*socks
=state
;
67 BEFOREPOLL_WANT_FDS(socks
->n_socks
);
68 for (i
=0; i
<socks
->n_socks
; i
++) {
69 fds
[i
].fd
=socks
->socks
[i
].fd
;
75 const char *af_name(int af
)
78 case AF_INET6
: return "IPv6";
79 case AF_INET
: return "IPv4";
80 case 0: return "(any)";
85 void udp_sock_experienced(struct log_if
*lg
, struct udpcommon
*uc
,
86 struct udpsocks
*socks
, struct udpsock
*us
,
87 const union iaddr
*dest
, int af
,
91 if (us
->experienced
[!!dest
][af
][success
]++)
93 lg_perror(lg
, uc
->cc
.cl
.description
, &uc
->cc
.loc
,
94 success ? M_INFO
: M_WARNING
,
95 success ?
0 : errnoval
,
96 "%s %s experiencing some %s %s%s%s%s%s%s",
97 socks
->desc
,iaddr_to_string(&us
->addr
),
98 success?
"success":"trouble",
99 dest?
"transmitting":"receiving",
100 af?
" ":"", af?
af_name(af
):"",
102 dest?
iaddr_to_string(dest
):"",
106 static void udp_socks_afterpoll(void *state
, struct pollfd
*fds
, int nfds
)
108 struct udpsocks
*socks
=state
;
109 struct udpcommon
*uc
=socks
->uc
;
116 struct commcommon
*cc
=&uc
->cc
;
118 for (i
=0; i
<socks
->n_socks
; i
++) {
119 struct udpsock
*us
=&socks
->socks
[i
];
120 if (i
>=nfds
) continue;
121 if (!(fds
[i
].revents
& POLLIN
)) continue;
122 assert(fds
[i
].fd
== us
->fd
);
125 fromlen
=sizeof(from
);
126 BUF_ASSERT_FREE(cc
->rbuf
);
127 BUF_ALLOC(cc
->rbuf
,"udp_afterpoll");
128 buffer_init(cc
->rbuf
,calculate_max_start_pad());
129 rv
=recvfrom(fd
, cc
->rbuf
->start
,
130 buf_remaining_space(cc
->rbuf
),
131 0, &from
.sa
, &fromlen
);
135 /* Check that the packet came from our poxy server;
136 we shouldn't be contacted directly by anybody else
137 (since they can trivially forge source addresses) */
138 if (!iaddr_equal(&from
,&uc
->proxy
,False
)) {
139 Message(M_INFO
,"udp: received packet that's not "
144 /* proxy protocol supports ipv4 transport only */
145 from
.sa
.sa_family
=AF_INET
;
146 BUF_GET_BYTES(unprepend
,cc
->rbuf
,&from
.sin
.sin_addr
,4);
147 buf_unprepend(cc
->rbuf
,2);
148 BUF_GET_BYTES(unprepend
,cc
->rbuf
,&from
.sin
.sin_port
,2);
154 done
=comm_notify(&cc
->notify
, cc
->rbuf
, &ca
);
156 udp_sock_experienced(0,uc
,socks
,us
,0,
157 from
.sa
.sa_family
,0,0);
160 if (cc
->rbuf
->size
>12 /* prevents traffic amplification */
161 && ((msgtype
=get_uint32(cc
->rbuf
->start
+8))
163 uint32_t source
,dest
;
164 /* Manufacture and send NAK packet */
165 source
=get_uint32(cc
->rbuf
->start
); /* Us */
166 dest
=get_uint32(cc
->rbuf
->start
+4); /* Them */
167 send_nak(&ca
,source
,dest
,msgtype
,cc
->rbuf
,"unwanted");
171 BUF_ASSERT_FREE(cc
->rbuf
);
173 if (errno
!=EINTR
&& !iswouldblock(errno
))
174 udp_sock_experienced(0,uc
,socks
,us
, 0,0, rv
,errno
);
181 static bool_t
udp_sendmsg(void *commst
, struct buffer_if
*buf
,
182 const struct comm_addr
*dest
)
184 struct udp
*st
=commst
;
185 struct udpcommon
*uc
=&st
->uc
;
186 struct udpsocks
*socks
=&st
->socks
;
190 struct udpsock
*us
=&socks
->socks
[0];
191 sa
=buf_prepend(buf
,8);
192 if (dest
->ia
.sa
.sa_family
!= AF_INET
) {
194 "udp: proxy means dropping outgoing non-IPv4 packet to %s\n",
195 iaddr_to_string(&dest
->ia
));
198 memcpy(sa
,&dest
->ia
.sin
.sin_addr
,4);
200 memcpy(sa
+6,&dest
->ia
.sin
.sin_port
,2);
201 int r
=sendto(us
->fd
,sa
,buf
->size
+8,0,&uc
->proxy
.sa
,
202 iaddr_socklen(&uc
->proxy
));
203 udp_sock_experienced(0,uc
,socks
,us
, &dest
->ia
,0, r
,errno
);
204 buf_unprepend(buf
,8);
207 bool_t allunsupported
=True
;
208 int af
=dest
->ia
.sa
.sa_family
;
209 for (i
=0; i
<socks
->n_socks
; i
++) {
210 struct udpsock
*us
=&socks
->socks
[i
];
211 if (us
->addr
.sa
.sa_family
!= af
)
212 /* no point even trying */
214 r
=sendto(us
->fd
, buf
->start
, buf
->size
, 0,
215 &dest
->ia
.sa
, iaddr_socklen(&dest
->ia
));
216 udp_sock_experienced(0,uc
,socks
,us
, &dest
->ia
,af
, r
,errno
);
217 if (r
>=0) return True
;
218 if (!(errno
==EAFNOSUPPORT
|| errno
==ENETUNREACH
))
219 /* who knows what that error means? */
220 allunsupported
=False
;
222 return !allunsupported
; /* see doc for comm_sendmsg_fn in secnet.h */
228 void udp_destroy_socket(struct udpcommon
*uc
, struct udpsock
*us
)
236 #define FAIL_LG 0, cc->cl.description, &cc->loc, failmsgclass
237 #define FAIL(...) do{ \
238 lg_perror(FAIL_LG,errno,__VA_ARGS__); \
242 static bool_t
record_socket_gotaddr(struct udpcommon
*uc
, struct udpsock
*us
,
245 struct commcommon
*cc
=&uc
->cc
;
246 socklen_t salen
=sizeof(us
->addr
);
247 int r
=getsockname(us
->fd
,&us
->addr
.sa
,&salen
);
248 if (r
) FAIL("getsockname()");
249 if (salen
>sizeof(us
->addr
)) { errno
=0; FAIL("getsockname() length"); }
256 bool_t
udp_import_socket(struct udpcommon
*uc
, struct udpsock
*us
,
257 int failmsgclass
, int fd
)
259 FILLZERO(us
->experienced
);
261 return record_socket_gotaddr(uc
,us
,failmsgclass
);
264 bool_t
udp_make_socket(struct udpcommon
*uc
, struct udpsock
*us
,
267 const union iaddr
*addr
=&us
->addr
;
268 struct commcommon
*cc
=&uc
->cc
;
271 FILLZERO(us
->experienced
);
272 us
->fd
=socket(addr
->sa
.sa_family
, SOCK_DGRAM
, IPPROTO_UDP
);
273 if (us
->fd
<0) FAIL("socket");
277 if (addr
->sa
.sa_family
==AF_INET6
) {
280 socklen_t optlen
=sizeof(optval
);
281 r
=setsockopt(us
->fd
,IPPROTO_IPV6
,IPV6_V6ONLY
,&optval
,optlen
);
282 if (r
) FAIL("setsockopt(,IPV6_V6ONLY,&1,)");
290 snprintf(desc
,sizeof(desc
),"authbind for %s: %s",
291 iaddr_to_string(addr
), uc
->authbind
);
293 /* XXX this fork() and waitpid() business needs to be hidden
294 in some system-specific library functions. */
297 FAIL("fork() for authbind");
299 char *argv
[5], addrstr
[33], portstr
[5];
303 switch (addr
->sa
.sa_family
) {
305 sprintf(addrstr
,"%08lX",(long)addr
->sin
.sin_addr
.s_addr
);
306 port
=addr
->sin
.sin_port
;
313 sprintf(addrstr
+i
*2,"%02X",addr
->sin6
.sin6_addr
.s6_addr
[i
]);
314 port
=addr
->sin6
.sin6_port
;
318 #endif /*CONFIG_IPV6*/
320 fatal("udp (%s:%d): unsupported address family for authbind",
321 cc
->loc
.file
,cc
->loc
.line
);
323 sprintf(portstr
,"%04X",port
);
324 argv
[0]=uc
->authbind
;
327 argv
[3]=(char*)addrfam
;
330 execvp(uc
->authbind
,argv
);
333 while (waitpid(c
,&status
,0)==-1) {
334 if (errno
==EINTR
) continue;
335 FAIL("waitpid for authbind");
338 if (WIFEXITED(status
) && WEXITSTATUS(status
)<127) {
339 int es
=WEXITSTATUS(status
);
340 lg_perror(FAIL_LG
,es
,
341 "%s exited with error exit status %d;"
342 " indicates error",desc
,es
);
344 lg_exitstatus(FAIL_LG
,status
,desc
);
349 if (bind(us
->fd
, &addr
->sa
, iaddr_socklen(addr
))!=0)
350 FAIL("bind (%s)",iaddr_to_string(addr
));
353 bool_t ok
=record_socket_gotaddr(uc
,us
,failmsgclass
);
354 if (!ok
) goto failed
;
359 udp_destroy_socket(uc
,us
);
365 void udp_socks_register(struct udpcommon
*uc
, struct udpsocks
*socks
,
371 register_for_poll(socks
,udp_socks_beforepoll
,udp_socks_afterpoll
,"udp");
374 void udp_socks_deregister(struct udpcommon
*uc
, struct udpsocks
*socks
)
377 deregister_for_poll(socks
->interest
);
380 void udp_socks_childpersist(struct udpcommon
*uc
, struct udpsocks
*socks
)
383 for (i
=0; i
<socks
->n_socks
; i
++)
384 udp_destroy_socket(uc
,&socks
->socks
[i
]);
387 static void udp_childpersist_hook(void *sst
, uint32_t new_phase
)
390 udp_socks_childpersist(&st
->uc
,&st
->socks
);
393 static void udp_phase_hook(void *sst
, uint32_t new_phase
)
396 struct udpsocks
*socks
=&st
->socks
;
397 struct udpcommon
*uc
=&st
->uc
;
399 for (i
=0; i
<socks
->n_socks
; i
++)
400 udp_make_socket(uc
,&socks
->socks
[i
],M_FATAL
);
402 udp_socks_register(uc
,socks
, uc
->use_proxy ?
"proxy" : "socket");
404 add_hook(PHASE_CHILDPERSIST
,udp_childpersist_hook
,st
);
407 static list_t
*udp_apply(closure_t
*self
, struct cloc loc
, dict_t
*context
,
416 COMM_APPLY(st
,&st
->uc
.cc
,udp_
,"udp",loc
);
417 COMM_APPLY_STANDARD(st
,&st
->uc
.cc
,"udp",args
);
418 UDP_APPLY_STANDARD(st
,&st
->uc
,"udp");
420 struct udpcommon
*uc
=&st
->uc
;
421 struct udpsocks
*socks
=&st
->socks
;
422 struct commcommon
*cc
=&uc
->cc
;
424 union iaddr defaultaddrs
[] = {
426 { .sin6
= { .sin6_family
=AF_INET6
,
427 .sin6_port
=htons(uc
->port
),
428 .sin6_addr
=IN6ADDR_ANY_INIT
} },
430 { .sin
= { .sin_family
=AF_INET
,
431 .sin_port
=htons(uc
->port
),
432 .sin_addr
= { .s_addr
=INADDR_ANY
} } }
435 caddrl
=dict_lookup(d
,"address");
436 socks
->n_socks
=caddrl ?
list_length(caddrl
) : (int)ARRAY_SIZE(defaultaddrs
);
437 if (socks
->n_socks
<=0 || socks
->n_socks
>UDP_MAX_SOCKETS
)
438 cfgfatal(cc
->loc
,"udp","`address' must be 1..%d addresses",
441 for (i
=0; i
<socks
->n_socks
; i
++) {
442 struct udpsock
*us
=&socks
->socks
[i
];
443 if (!list_length(caddrl
)) {
444 us
->addr
=defaultaddrs
[i
];
446 string_item_to_iaddr(list_elem(caddrl
,i
),uc
->port
,&us
->addr
,"udp");
451 l
=dict_lookup(d
,"proxy");
454 uc
->proxy
.sa
.sa_family
=AF_INET
;
456 if (!item
|| item
->type
!=t_string
) {
457 cfgfatal(cc
->loc
,"udp","proxy must supply ""addr"",port\n");
459 a
=string_item_to_ipaddr(item
,"proxy");
460 uc
->proxy
.sin
.sin_addr
.s_addr
=htonl(a
);
462 if (!item
|| item
->type
!=t_number
) {
463 cfgfatal(cc
->loc
,"udp","proxy must supply ""addr"",port\n");
465 uc
->proxy
.sin
.sin_port
=htons(item
->data
.number
);
468 update_max_start_pad(&comm_max_start_pad
, uc
->use_proxy ?
8 : 0);
470 add_hook(PHASE_GETRESOURCES
,udp_phase_hook
,st
);
472 return new_closure(&cc
->cl
);
475 void udp_module(dict_t
*dict
)
477 add_closure(dict
,"udp",udp_apply
);