Fix crash in ocsp_url extract
[exim.git] / src / src / ip.c
CommitLineData
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
5a66c31b 5/* Copyright (c) University of Cambridge 1995 - 2014 */
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6/* See the file NOTICE for conditions of use and distribution. */
7
8/* Functions for doing things with sockets. With the advent of IPv6 this has
9got messier, so that it's worth pulling out the code into separate functions
10that other parts of Exim can call, expecially as there are now several
11different places in the code where sockets are used. */
12
13
14#include "exim.h"
15
16
17/*************************************************
18* Create a socket *
19*************************************************/
20
21/* Socket creation happens in a number of places so it's packaged here for
22convenience.
23
24Arguments:
25 type SOCK_DGRAM or SOCK_STREAM
26 af AF_INET or AF_INET6
27
28Returns: socket number or -1 on failure
29*/
30
31int
32ip_socket(int type, int af)
33{
34int sock = socket(af, type, 0);
35if (sock < 0)
36 log_write(0, LOG_MAIN, "IPv%c socket creation failed: %s",
37 (af == AF_INET6)? '6':'4', strerror(errno));
38return sock;
39}
40
41
42
43
44#if HAVE_IPV6
45/*************************************************
46* Convert printing address to numeric *
47*************************************************/
48
49/* This function converts the textual form of an IP address into a numeric form
50in an appropriate structure in an IPv6 environment. The getaddrinfo() function
51can (apparently) handle more complicated addresses (e.g. those containing
52scopes) than inet_pton() in some environments. We use hints to tell it that the
53input must be a numeric address.
54
55However, apparently some operating systems (or libraries) don't support
56getaddrinfo(), so there is a build-time option to revert to inet_pton() (which
57does not support scopes).
58
59Arguments:
60 address textual form of the address
61 addr where to copy back the answer
62
63Returns: nothing - failure provokes a panic-die
64*/
65
66static void
a56cc2b8 67ip_addrinfo(const uschar *address, struct sockaddr_in6 *saddr)
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68{
69#ifdef IPV6_USE_INET_PTON
70
a56cc2b8 71 if (inet_pton(AF_INET6, CCS address, &saddr->sin6_addr) != 1)
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72 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
73 "IP address", address);
74 saddr->sin6_family = AF_INET6;
75
76#else
77
78 int rc;
79 struct addrinfo hints, *res;
80 memset(&hints, 0, sizeof(hints));
81 hints.ai_family = AF_INET6;
82 hints.ai_socktype = SOCK_STREAM;
83 hints.ai_flags = AI_NUMERICHOST;
a56cc2b8 84 if ((rc = getaddrinfo(CCS address, NULL, &hints, &res)) != 0 || res == NULL)
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85 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
86 "IP address: %s", address,
87 (rc == 0)? "NULL result returned" : gai_strerror(rc));
88 memcpy(saddr, res->ai_addr, res->ai_addrlen);
89 freeaddrinfo(res);
90
91#endif
92}
93#endif /* HAVE_IPV6 */
94
95
96/*************************************************
97* Bind socket to interface and port *
98*************************************************/
99
100/* This function binds a socket to a local interface address and port. For a
101wildcard IPv6 bind, the address is ":".
102
103Arguments:
104 sock the socket
105 af AF_INET or AF_INET6 - the socket type
106 address the IP address, in text form
107 port the IP port (host order)
108
109Returns: the result of bind()
110*/
111
112int
113ip_bind(int sock, int af, uschar *address, int port)
114{
115int s_len;
116union sockaddr_46 sin;
117memset(&sin, 0, sizeof(sin));
118
119/* Setup code when using an IPv6 socket. The wildcard address is ":", to
120ensure an IPv6 socket is used. */
121
122#if HAVE_IPV6
123if (af == AF_INET6)
124 {
125 if (address[0] == ':' && address[1] == 0)
126 {
127 sin.v6.sin6_family = AF_INET6;
128 sin.v6.sin6_addr = in6addr_any;
129 }
130 else
131 {
132 ip_addrinfo(address, &sin.v6); /* Panic-dies on error */
133 }
134 sin.v6.sin6_port = htons(port);
135 s_len = sizeof(sin.v6);
136 }
137else
138#else /* HAVE_IPv6 */
139af = af; /* Avoid compiler warning */
140#endif /* HAVE_IPV6 */
141
142/* Setup code when using IPv4 socket. The wildcard address is "". */
143
144 {
145 sin.v4.sin_family = AF_INET;
146 sin.v4.sin_port = htons(port);
147 s_len = sizeof(sin.v4);
148 if (address[0] == 0)
149 sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)INADDR_ANY;
150 else
151 sin.v4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(CS address);
152 }
153
154/* Now we can call the bind() function */
155
156return bind(sock, (struct sockaddr *)&sin, s_len);
157}
158
159
160
161/*************************************************
162* Connect socket to remote host *
163*************************************************/
164
165/* This function connects a socket to a remote address and port. The socket may
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166or may not have previously been bound to a local interface. The socket is not
167closed, even in cases of error. It is expected that the calling function, which
168created the socket, will be the one that closes it.
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169
170Arguments:
171 sock the socket
172 af AF_INET6 or AF_INET for the socket type
173 address the remote address, in text form
174 port the remote port
b1f8e4f8 175 timeout a timeout (zero for indefinite timeout)
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176
177Returns: 0 on success; -1 on failure, with errno set
178*/
179
180int
a56cc2b8 181ip_connect(int sock, int af, const uschar *address, int port, int timeout)
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182{
183struct sockaddr_in s_in4;
184struct sockaddr *s_ptr;
185int s_len, rc, save_errno;
186
187/* For an IPv6 address, use an IPv6 sockaddr structure. */
188
189#if HAVE_IPV6
190struct sockaddr_in6 s_in6;
191if (af == AF_INET6)
192 {
193 memset(&s_in6, 0, sizeof(s_in6));
194 ip_addrinfo(address, &s_in6); /* Panic-dies on error */
195 s_in6.sin6_port = htons(port);
196 s_ptr = (struct sockaddr *)&s_in6;
197 s_len = sizeof(s_in6);
198 }
199else
200#else /* HAVE_IPV6 */
201af = af; /* Avoid compiler warning */
202#endif /* HAVE_IPV6 */
203
204/* For an IPv4 address, use an IPv4 sockaddr structure, even on a system with
205IPv6 support. */
206
207 {
208 memset(&s_in4, 0, sizeof(s_in4));
209 s_in4.sin_family = AF_INET;
210 s_in4.sin_port = htons(port);
a56cc2b8 211 s_in4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(CCS address);
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212 s_ptr = (struct sockaddr *)&s_in4;
213 s_len = sizeof(s_in4);
214 }
215
216/* If no connection timeout is set, just call connect() without setting a
217timer, thereby allowing the inbuilt OS timeout to operate. */
218
219sigalrm_seen = FALSE;
220if (timeout > 0) alarm(timeout);
221rc = connect(sock, s_ptr, s_len);
222save_errno = errno;
223alarm(0);
224
225/* There is a testing facility for simulating a connection timeout, as I
226can't think of any other way of doing this. It converts a connection refused
75e0e026 227into a timeout if the timeout is set to 999999. */
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228
229if (running_in_test_harness)
230 {
75e0e026 231 if (save_errno == ECONNREFUSED && timeout == 999999)
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232 {
233 rc = -1;
234 save_errno = EINTR;
235 sigalrm_seen = TRUE;
236 }
237 }
238
239/* Success */
240
241if (rc >= 0) return 0;
242
243/* A failure whose error code is "Interrupted system call" is in fact
244an externally applied timeout if the signal handler has been run. */
245
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246errno = (save_errno == EINTR && sigalrm_seen)? ETIMEDOUT : save_errno;
247return -1;
248}
249
250
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251
252/*************************************************
253* Create connected socket to remote host *
254*************************************************/
255
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256/* Create a socket and connect to host (name or number, ipv6 ok)
257 at one of port-range.
a6d4c44e 258
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259Arguments:
260 type SOCK_DGRAM or SOCK_STREAM
261 af AF_INET6 or AF_INET for the socket type
262 address the remote address, in text form
263 portlo,porthi the remote port range
264 timeout a timeout
265 connhost if not NULL, host_item filled in with connection details
266 errstr pointer for allocated string on error
267
268Return:
269 socket fd, or -1 on failure (having allocated an error string)
270*/
271int
272ip_connectedsocket(int type, const uschar * hostname, int portlo, int porthi,
273 int timeout, host_item * connhost, uschar ** errstr)
274{
275int namelen, port;
276host_item shost;
277host_item *h;
278int af = 0, fd, fd4 = -1, fd6 = -1;
279
280shost.next = NULL;
281shost.address = NULL;
282shost.port = portlo;
283shost.mx = -1;
284
285namelen = Ustrlen(hostname);
286
287/* Anything enclosed in [] must be an IP address. */
288
289if (hostname[0] == '[' &&
290 hostname[namelen - 1] == ']')
291 {
292 uschar * host = string_copy(hostname);
293 host[namelen - 1] = 0;
294 host++;
295 if (string_is_ip_address(host, NULL) == 0)
296 {
297 *errstr = string_sprintf("malformed IP address \"%s\"", hostname);
298 return -1;
299 }
300 shost.name = shost.address = host;
301 }
302
303/* Otherwise check for an unadorned IP address */
304
305else if (string_is_ip_address(hostname, NULL) != 0)
306 shost.name = shost.address = string_copy(hostname);
307
308/* Otherwise lookup IP address(es) from the name */
309
310else
311 {
312 shost.name = string_copy(hostname);
313 if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE, NULL,
314 FALSE) != HOST_FOUND)
315 {
316 *errstr = string_sprintf("no IP address found for host %s", shost.name);
317 return -1;
318 }
319 }
320
321/* Try to connect to the server - test each IP till one works */
322
323for (h = &shost; h != NULL; h = h->next)
324 {
325 fd = (Ustrchr(h->address, ':') != 0)
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326 ? (fd6 < 0) ? (fd6 = ip_socket(type, af = AF_INET6)) : fd6
327 : (fd4 < 0) ? (fd4 = ip_socket(type, af = AF_INET )) : fd4;
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328
329 if (fd < 0)
330 {
331 *errstr = string_sprintf("failed to create socket: %s", strerror(errno));
332 goto bad;
333 }
334
335 for(port = portlo; port <= porthi; port++)
336 if (ip_connect(fd, af, h->address, port, timeout) == 0)
337 {
338 if (fd != fd6) close(fd6);
339 if (fd != fd4) close(fd4);
340 if (connhost) {
341 h->port = port;
342 *connhost = *h;
343 connhost->next = NULL;
344 }
345 return fd;
346 }
347 }
348
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349*errstr = string_sprintf("failed to connect to any address for %s: %s",
350 hostname, strerror(errno));
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351
352bad:
353 close(fd4); close(fd6); return -1;
354}
355
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356
357/*************************************************
358* Set keepalive on a socket *
359*************************************************/
360
361/* Can be called for both incoming and outgoing sockets.
362
363Arguments:
364 sock the socket
365 address the remote host address, for failure logging
366 torf true for outgoing connection, false for incoming
367
368Returns: nothing
369*/
370
371void
372ip_keepalive(int sock, uschar *address, BOOL torf)
373{
374int fodder = 1;
375if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
376 (uschar *)(&fodder), sizeof(fodder)) != 0)
377 log_write(0, LOG_MAIN, "setsockopt(SO_KEEPALIVE) on connection %s %s "
378 "failed: %s", torf? "to":"from", address, strerror(errno));
379}
380
381
382
383/*************************************************
384* Receive from a socket with timeout *
385*************************************************/
386
4e71661f 387/*
059ec3d9 388Arguments:
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389 fd the file descriptor
390 timeout the timeout, seconds
391Returns: TRUE => ready for i/o
392 FALSE => timed out, or other error
059ec3d9 393*/
4e71661f
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394BOOL
395fd_ready(int fd, int timeout)
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396{
397fd_set select_inset;
398struct timeval tv;
19050083 399time_t start_recv = time(NULL);
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400int rc;
401
4e71661f
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402if (timeout <= 0)
403 {
404 errno = ETIMEDOUT;
405 return FALSE;
406 }
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407/* Wait until the socket is ready */
408
409for (;;)
410 {
411 FD_ZERO (&select_inset);
4e71661f 412 FD_SET (fd, &select_inset);
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413 tv.tv_sec = timeout;
414 tv.tv_usec = 0;
415
0f0c8159 416 /*DEBUG(D_transport) debug_printf("waiting for data on fd\n");*/
4e71661f 417 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&select_inset, NULL, NULL, &tv);
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418
419 /* If some interrupt arrived, just retry. We presume this to be rare,
420 but it can happen (e.g. the SIGUSR1 signal sent by exiwhat causes
421 select() to exit).
422
423 Aug 2004: Somebody set up a cron job that ran exiwhat every 2 minutes, making
424 the interrupt not at all rare. Since the timeout is typically more than 2
425 minutes, the effect was to block the timeout completely. To prevent this
426 happening again, we do an explicit time test. */
427
428 if (rc < 0 && errno == EINTR)
429 {
430 DEBUG(D_transport) debug_printf("EINTR while waiting for socket data\n");
431 if (time(NULL) - start_recv < timeout) continue;
432 DEBUG(D_transport) debug_printf("total wait time exceeds timeout\n");
433 }
434
435 /* Handle a timeout, and treat any other select error as a timeout, including
436 an EINTR when we have been in this loop for longer than timeout. */
437
438 if (rc <= 0)
439 {
440 errno = ETIMEDOUT;
4e71661f 441 return FALSE;
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PH
442 }
443
444 /* If the socket is ready, break out of the loop. */
445
4e71661f 446 if (FD_ISSET(fd, &select_inset)) break;
059ec3d9 447 }
4e71661f
JH
448return TRUE;
449}
450
451/* The timeout is implemented using select(), and we loop to cover select()
452getting interrupted, and the possibility of select() returning with a positive
453result but no ready descriptor. Is this in fact possible?
454
455Arguments:
456 sock the socket
457 buffer to read into
458 bufsize the buffer size
459 timeout the timeout
460
461Returns: > 0 => that much data read
462 <= 0 on error or EOF; errno set - zero for EOF
463*/
464
465int
466ip_recv(int sock, uschar *buffer, int buffsize, int timeout)
467{
468int rc;
469
470if (!fd_ready(sock, timeout))
471 return -1;
059ec3d9
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472
473/* The socket is ready, read from it (via TLS if it's active). On EOF (i.e.
474close down of the connection), set errno to zero; otherwise leave it alone. */
475
476#ifdef SUPPORT_TLS
817d9f57
JH
477if (tls_out.active == sock)
478 rc = tls_read(FALSE, buffer, buffsize);
479else if (tls_in.active == sock)
480 rc = tls_read(TRUE, buffer, buffsize);
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481else
482#endif
483 rc = recv(sock, buffer, buffsize, 0);
484
485if (rc > 0) return rc;
486if (rc == 0) errno = 0;
487return -1;
488}
489
490
9e4f5962
PP
491
492
493/*************************************************
13363eba
PP
494* Lookup address family of potential socket *
495*************************************************/
496
497/* Given a file-descriptor, check to see if it's a socket and, if so,
498return the address family; detects IPv4 vs IPv6. If not a socket then
499return -1.
500
501The value 0 is typically AF_UNSPEC, which should not be seen on a connected
502fd. If the return is -1, the errno will be from getsockname(); probably
503ENOTSOCK or ECONNRESET.
504
505Arguments: socket-or-not fd
506Returns: address family or -1
507*/
508
509int
510ip_get_address_family(int fd)
511{
512struct sockaddr_storage ss;
513socklen_t sslen = sizeof(ss);
514
515if (getsockname(fd, (struct sockaddr *) &ss, &sslen) < 0)
516 return -1;
517
518return (int) ss.ss_family;
519}
520
521
522
523
524/*************************************************
9e4f5962
PP
525* Lookup DSCP settings for a socket *
526*************************************************/
527
528struct dscp_name_tableentry {
529 const uschar *name;
530 int value;
531};
532/* Keep both of these tables sorted! */
533static struct dscp_name_tableentry dscp_table[] = {
534#ifdef IPTOS_DSCP_AF11
36a3ae5f
PP
535 { CUS"af11", IPTOS_DSCP_AF11 },
536 { CUS"af12", IPTOS_DSCP_AF12 },
537 { CUS"af13", IPTOS_DSCP_AF13 },
538 { CUS"af21", IPTOS_DSCP_AF21 },
539 { CUS"af22", IPTOS_DSCP_AF22 },
540 { CUS"af23", IPTOS_DSCP_AF23 },
541 { CUS"af31", IPTOS_DSCP_AF31 },
542 { CUS"af32", IPTOS_DSCP_AF32 },
543 { CUS"af33", IPTOS_DSCP_AF33 },
544 { CUS"af41", IPTOS_DSCP_AF41 },
545 { CUS"af42", IPTOS_DSCP_AF42 },
546 { CUS"af43", IPTOS_DSCP_AF43 },
547 { CUS"ef", IPTOS_DSCP_EF },
9e4f5962
PP
548#endif
549#ifdef IPTOS_LOWCOST
36a3ae5f 550 { CUS"lowcost", IPTOS_LOWCOST },
9e4f5962 551#endif
36a3ae5f 552 { CUS"lowdelay", IPTOS_LOWDELAY },
9e4f5962 553#ifdef IPTOS_MINCOST
36a3ae5f 554 { CUS"mincost", IPTOS_MINCOST },
9e4f5962 555#endif
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PP
556 { CUS"reliability", IPTOS_RELIABILITY },
557 { CUS"throughput", IPTOS_THROUGHPUT }
9e4f5962
PP
558};
559static int dscp_table_size =
560 sizeof(dscp_table) / sizeof(struct dscp_name_tableentry);
561
562/* DSCP values change by protocol family, and so do the options used for
2a1b36b3
PP
563setsockopt(); this utility does all the lookups. It takes an unexpanded
564option string, expands it, strips off affix whitespace, then checks if it's
565a number. If all of what's left is a number, then that's how the option will
566be parsed and success/failure is a range check. If it's not all a number,
567then it must be a supported keyword.
9e4f5962
PP
568
569Arguments:
570 dscp_name a string, so far unvalidated
571 af address_family in use
572 level setsockopt level to use
573 optname setsockopt name to use
574 dscp_value value for dscp_name
575
576Returns: TRUE if okay to setsockopt(), else FALSE
2a1b36b3
PP
577
578*level and *optname may be set even if FALSE is returned
9e4f5962
PP
579*/
580
581BOOL
582dscp_lookup(const uschar *dscp_name, int af,
583 int *level, int *optname, int *dscp_value)
584{
2a1b36b3 585uschar *dscp_lookup, *p;
9e4f5962 586int first, last;
2a1b36b3 587long rawlong;
9e4f5962
PP
588
589if (af == AF_INET)
590 {
591 *level = IPPROTO_IP;
592 *optname = IP_TOS;
593 }
bb7b9411 594#if HAVE_IPV6 && defined(IPV6_TCLASS)
9e4f5962
PP
595else if (af == AF_INET6)
596 {
597 *level = IPPROTO_IPV6;
598 *optname = IPV6_TCLASS;
599 }
b301a50b 600#endif
9e4f5962
PP
601else
602 {
603 DEBUG(D_transport)
604 debug_printf("Unhandled address family %d in dscp_lookup()\n", af);
605 return FALSE;
606 }
607if (!dscp_name)
608 {
609 DEBUG(D_transport)
610 debug_printf("[empty DSCP]\n");
611 return FALSE;
612 }
613dscp_lookup = expand_string(US dscp_name);
614if (dscp_lookup == NULL || *dscp_lookup == '\0')
615 return FALSE;
616
2a1b36b3
PP
617p = dscp_lookup + Ustrlen(dscp_lookup) - 1;
618while (isspace(*p)) *p-- = '\0';
619while (isspace(*dscp_lookup) && dscp_lookup < p) dscp_lookup++;
620if (*dscp_lookup == '\0')
621 return FALSE;
622
623rawlong = Ustrtol(dscp_lookup, &p, 0);
624if (p != dscp_lookup && *p == '\0')
625 {
626 /* We have six bits available, which will end up shifted to fit in 0xFC mask.
627 RFC 2597 defines the values unshifted. */
628 if (rawlong < 0 || rawlong > 0x3F)
629 {
630 DEBUG(D_transport)
631 debug_printf("DSCP value %ld out of range, ignored.\n", rawlong);
632 return FALSE;
633 }
634 *dscp_value = rawlong << 2;
635 return TRUE;
636 }
637
9e4f5962
PP
638first = 0;
639last = dscp_table_size;
640while (last > first)
641 {
642 int middle = (first + last)/2;
643 int c = Ustrcmp(dscp_lookup, dscp_table[middle].name);
644 if (c == 0)
645 {
646 *dscp_value = dscp_table[middle].value;
647 return TRUE;
648 }
649 else if (c > 0)
650 {
651 first = middle + 1;
652 }
653 else
654 {
655 last = middle;
656 }
657 }
658return FALSE;
659}
660
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PP
661void
662dscp_list_to_stream(FILE *stream)
663{
664int i;
665for (i=0; i < dscp_table_size; ++i)
666 fprintf(stream, "%s\n", dscp_table[i].name);
667}
668
9e4f5962 669
059ec3d9 670/* End of ip.c */