[hcoop/zz_old/debian/djbdns.git] / dns_transmit.c

#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include "socket.h"
#include "alloc.h"
#include "error.h"
#include "byte.h"
#include "uint16.h"
#include "dns.h"

static int serverwantstcp(const char *buf,unsigned int len)
{
  char out[12];

  if (!dns_packet_copy(buf,len,0,out,12)) return 1;
  if (out[2] & 2) return 1;
  return 0;
}

static int serverfailed(const char *buf,unsigned int len)
{
  char out[12];
  unsigned int rcode;

  if (!dns_packet_copy(buf,len,0,out,12)) return 1;
  rcode = out[3];
  rcode &= 15;
  if (rcode && (rcode != 3)) { errno = error_again; return 1; }
  return 0;
}

static int irrelevant(const struct dns_transmit *d,const char *buf,unsigned int len)
{
  char out[12];
  char *dn;
  unsigned int pos;

  pos = dns_packet_copy(buf,len,0,out,12); if (!pos) return 1;
  if (byte_diff(out,2,d->query + 2)) return 1;
  if (out[4] != 0) return 1;
  if (out[5] != 1) return 1;

  dn = 0;
  pos = dns_packet_getname(buf,len,pos,&dn); if (!pos) return 1;
  if (!dns_domain_equal(dn,d->query + 14)) { alloc_free(dn); return 1; }
  alloc_free(dn);

  pos = dns_packet_copy(buf,len,pos,out,4); if (!pos) return 1;
  if (byte_diff(out,2,d->qtype)) return 1;
  if (byte_diff(out + 2,2,DNS_C_IN)) return 1;

  return 0;
}

static void packetfree(struct dns_transmit *d)
{
  if (!d->packet) return;
  alloc_free(d->packet);
  d->packet = 0;
}

static void queryfree(struct dns_transmit *d)
{
  if (!d->query) return;
  alloc_free(d->query);
  d->query = 0;
}

static void socketfree(struct dns_transmit *d)
{
  if (!d->s1) return;
  close(d->s1 - 1);
  d->s1 = 0;
}

void dns_transmit_free(struct dns_transmit *d)
{
  queryfree(d);
  socketfree(d);
  packetfree(d);
}

static int randombind(struct dns_transmit *d)
{
  int j;

  for (j = 0;j < 10;++j)
    if (socket_bind4(d->s1 - 1,d->localip,1025 + dns_random(64510)) == 0)
      return 0;
  if (socket_bind4(d->s1 - 1,d->localip,0) == 0)
    return 0;
  return -1;
}

static const int timeouts[4] = { 1, 3, 11, 45 };

static int thisudp(struct dns_transmit *d)
{
  const char *ip;

  socketfree(d);

  while (d->udploop < 4) {
    for (;d->curserver < 16;++d->curserver) {
      ip = d->servers + 4 * d->curserver;
      if (byte_diff(ip,4,"\0\0\0\0")) {
	d->query[2] = dns_random(256);
	d->query[3] = dns_random(256);
  
        d->s1 = 1 + socket_udp();
        if (!d->s1) { dns_transmit_free(d); return -1; }
	if (randombind(d) == -1) { dns_transmit_free(d); return -1; }

        if (socket_connect4(d->s1 - 1,ip,53) == 0)
          if (send(d->s1 - 1,d->query + 2,d->querylen - 2,0) == d->querylen - 2) {
            struct taia now;
            taia_now(&now);
            taia_uint(&d->deadline,timeouts[d->udploop]);
            taia_add(&d->deadline,&d->deadline,&now);
            d->tcpstate = 0;
            return 0;
          }
  
        socketfree(d);
      }
    }

    ++d->udploop;
    d->curserver = 0;
  }

  dns_transmit_free(d); return -1;
}

static int firstudp(struct dns_transmit *d)
{
  d->curserver = 0;
  return thisudp(d);
}

static int nextudp(struct dns_transmit *d)
{
  ++d->curserver;
  return thisudp(d);
}

static int thistcp(struct dns_transmit *d)
{
  struct taia now;
  const char *ip;

  socketfree(d);
  packetfree(d);

  for (;d->curserver < 16;++d->curserver) {
    ip = d->servers + 4 * d->curserver;
    if (byte_diff(ip,4,"\0\0\0\0")) {
      d->query[2] = dns_random(256);
      d->query[3] = dns_random(256);

      d->s1 = 1 + socket_tcp();
      if (!d->s1) { dns_transmit_free(d); return -1; }
      if (randombind(d) == -1) { dns_transmit_free(d); return -1; }
  
      taia_now(&now);
      taia_uint(&d->deadline,10);
      taia_add(&d->deadline,&d->deadline,&now);
      if (socket_connect4(d->s1 - 1,ip,53) == 0) {
        d->tcpstate = 2;
        return 0;
      }
      if ((errno == error_inprogress) || (errno == error_wouldblock)) {
        d->tcpstate = 1;
        return 0;
      }
  
      socketfree(d);
    }
  }

  dns_transmit_free(d); return -1;
}

static int firsttcp(struct dns_transmit *d)
{
  d->curserver = 0;
  return thistcp(d);
}

static int nexttcp(struct dns_transmit *d)
{
  ++d->curserver;
  return thistcp(d);
}

int dns_transmit_start(struct dns_transmit *d,const char servers[64],int flagrecursive,const char *q,const char qtype[2],const char localip[4])
{
  unsigned int len;

  dns_transmit_free(d);
  errno = error_io;

  len = dns_domain_length(q);
  d->querylen = len + 18;
  d->query = alloc(d->querylen);
  if (!d->query) return -1;

  uint16_pack_big(d->query,len + 16);
  byte_copy(d->query + 2,12,flagrecursive ? "\0\0\1\0\0\1\0\0\0\0\0\0" : "\0\0\0\0\0\1\0\0\0\0\0\0gcc-bug-workaround");
  byte_copy(d->query + 14,len,q);
  byte_copy(d->query + 14 + len,2,qtype);
  byte_copy(d->query + 16 + len,2,DNS_C_IN);

  byte_copy(d->qtype,2,qtype);
  d->servers = servers;
  byte_copy(d->localip,4,localip);

  d->udploop = flagrecursive ? 1 : 0;

  if (len + 16 > 512) return firsttcp(d);
  return firstudp(d);
}

void dns_transmit_io(struct dns_transmit *d,iopause_fd *x,struct taia *deadline)
{
  x->fd = d->s1 - 1;

  switch(d->tcpstate) {
    case 0: case 3: case 4: case 5:
      x->events = IOPAUSE_READ;
      break;
    case 1: case 2:
      x->events = IOPAUSE_WRITE;
      break;
  }

  if (taia_less(&d->deadline,deadline))
    *deadline = d->deadline;
}

int dns_transmit_get(struct dns_transmit *d,const iopause_fd *x,const struct taia *when)
{
  char udpbuf[513];
  unsigned char ch;
  int r;
  int fd;

  errno = error_io;
  fd = d->s1 - 1;

  if (!x->revents) {
    if (taia_less(when,&d->deadline)) return 0;
    errno = error_timeout;
    if (d->tcpstate == 0) return nextudp(d);
    return nexttcp(d);
  }

  if (d->tcpstate == 0) {
/*
have attempted to send UDP query to each server udploop times
have sent query to curserver on UDP socket s
*/
    r = recv(fd,udpbuf,sizeof udpbuf,0);
    if (r <= 0) {
      if (errno == error_connrefused) if (d->udploop == 2) return 0;
      return nextudp(d);
    }
    if (r + 1 > sizeof udpbuf) return 0;

    if (irrelevant(d,udpbuf,r)) return 0;
    if (serverwantstcp(udpbuf,r)) return firsttcp(d);
    if (serverfailed(udpbuf,r)) {
      if (d->udploop == 2) return 0;
      return nextudp(d);
    }
    socketfree(d);

    d->packetlen = r;
    d->packet = alloc(d->packetlen);
    if (!d->packet) { dns_transmit_free(d); return -1; }
    byte_copy(d->packet,d->packetlen,udpbuf);
    queryfree(d);
    return 1;
  }

  if (d->tcpstate == 1) {
/*
have sent connection attempt to curserver on TCP socket s
pos not defined
*/
    if (!socket_connected(fd)) return nexttcp(d);
    d->pos = 0;
    d->tcpstate = 2;
    return 0;
  }

  if (d->tcpstate == 2) {
/*
have connection to curserver on TCP socket s
have sent pos bytes of query
*/
    r = write(fd,d->query + d->pos,d->querylen - d->pos);
    if (r <= 0) return nexttcp(d);
    d->pos += r;
    if (d->pos == d->querylen) {
      struct taia now;
      taia_now(&now);
      taia_uint(&d->deadline,10);
      taia_add(&d->deadline,&d->deadline,&now);
      d->tcpstate = 3;
    }
    return 0;
  }

  if (d->tcpstate == 3) {
/*
have sent entire query to curserver on TCP socket s
pos not defined
*/
    r = read(fd,&ch,1);
    if (r <= 0) return nexttcp(d);
    d->packetlen = ch;
    d->tcpstate = 4;
    return 0;
  }

  if (d->tcpstate == 4) {
/*
have sent entire query to curserver on TCP socket s
pos not defined
have received one byte of packet length into packetlen
*/
    r = read(fd,&ch,1);
    if (r <= 0) return nexttcp(d);
    d->packetlen <<= 8;
    d->packetlen += ch;
    d->tcpstate = 5;
    d->pos = 0;
    d->packet = alloc(d->packetlen);
    if (!d->packet) { dns_transmit_free(d); return -1; }
    return 0;
  }

  if (d->tcpstate == 5) {
/*
have sent entire query to curserver on TCP socket s
have received entire packet length into packetlen
packet is allocated
have received pos bytes of packet
*/
    r = read(fd,d->packet + d->pos,d->packetlen - d->pos);
    if (r <= 0) return nexttcp(d);
    d->pos += r;
    if (d->pos < d->packetlen) return 0;

    socketfree(d);
    if (irrelevant(d,d->packet,d->packetlen)) return nexttcp(d);
    if (serverwantstcp(d->packet,d->packetlen)) return nexttcp(d);
    if (serverfailed(d->packet,d->packetlen)) return nexttcp(d);

    queryfree(d);
    return 1;
  }

  return 0;
}
Commit	Line	Data
dc0d77d7 CE	1	#include <sys/types.h>
	2	#include <sys/socket.h>
	3	#include <unistd.h>
	4	#include "socket.h"
	5	#include "alloc.h"
	6	#include "error.h"
	7	#include "byte.h"
	8	#include "uint16.h"
	9	#include "dns.h"
	10
	11	static int serverwantstcp(const char *buf,unsigned int len)
	12	{
	13	char out[12];
	14
	15	if (!dns_packet_copy(buf,len,0,out,12)) return 1;
	16	if (out[2] & 2) return 1;
	17	return 0;
	18	}
	19
	20	static int serverfailed(const char *buf,unsigned int len)
	21	{
	22	char out[12];
	23	unsigned int rcode;
	24
	25	if (!dns_packet_copy(buf,len,0,out,12)) return 1;
	26	rcode = out[3];
	27	rcode &= 15;
	28	if (rcode && (rcode != 3)) { errno = error_again; return 1; }
	29	return 0;
	30	}
	31
	32	static int irrelevant(const struct dns_transmit d,const char buf,unsigned int len)
	33	{
	34	char out[12];
	35	char *dn;
	36	unsigned int pos;
	37
	38	pos = dns_packet_copy(buf,len,0,out,12); if (!pos) return 1;
	39	if (byte_diff(out,2,d->query + 2)) return 1;
	40	if (out[4] != 0) return 1;
	41	if (out[5] != 1) return 1;
	42
	43	dn = 0;
	44	pos = dns_packet_getname(buf,len,pos,&dn); if (!pos) return 1;
	45	if (!dns_domain_equal(dn,d->query + 14)) { alloc_free(dn); return 1; }
	46	alloc_free(dn);
	47
	48	pos = dns_packet_copy(buf,len,pos,out,4); if (!pos) return 1;
	49	if (byte_diff(out,2,d->qtype)) return 1;
	50	if (byte_diff(out + 2,2,DNS_C_IN)) return 1;
	51
	52	return 0;
	53	}
	54
	55	static void packetfree(struct dns_transmit *d)
	56	{
	57	if (!d->packet) return;
	58	alloc_free(d->packet);
	59	d->packet = 0;
	60	}
	61
	62	static void queryfree(struct dns_transmit *d)
	63	{
	64	if (!d->query) return;
65	alloc_free(d->query);
66	d->query = 0;
67	}
68
69	static void socketfree(struct dns_transmit *d)
70	{
71	if (!d->s1) return;
72	close(d->s1 - 1);
73	d->s1 = 0;
74	}
75
76	void dns_transmit_free(struct dns_transmit *d)
77	{
78	queryfree(d);
79	socketfree(d);
80	packetfree(d);
81	}
82
83	static int randombind(struct dns_transmit *d)
84	{
85	int j;
86
87	for (j = 0;j < 10;++j)
88	if (socket_bind4(d->s1 - 1,d->localip,1025 + dns_random(64510)) == 0)
89	return 0;
90	if (socket_bind4(d->s1 - 1,d->localip,0) == 0)
91	return 0;
92	return -1;
93	}
94
95	static const int timeouts[4] = { 1, 3, 11, 45 };
96
97	static int thisudp(struct dns_transmit *d)
98	{
99	const char *ip;
100
101	socketfree(d);
102
103	while (d->udploop < 4) {
104	for (;d->curserver < 16;++d->curserver) {
105	ip = d->servers + 4 * d->curserver;
106	if (byte_diff(ip,4,"\0\0\0\0")) {
107	d->query[2] = dns_random(256);
108	d->query[3] = dns_random(256);
109
110	d->s1 = 1 + socket_udp();
111	if (!d->s1) { dns_transmit_free(d); return -1; }
112	if (randombind(d) == -1) { dns_transmit_free(d); return -1; }
113
114	if (socket_connect4(d->s1 - 1,ip,53) == 0)
115	if (send(d->s1 - 1,d->query + 2,d->querylen - 2,0) == d->querylen - 2) {
116	struct taia now;
117	taia_now(&now);
118	taia_uint(&d->deadline,timeouts[d->udploop]);
119	taia_add(&d->deadline,&d->deadline,&now);
120	d->tcpstate = 0;
121	return 0;
122	}
123
124	socketfree(d);
125	}
126	}
127
128	++d->udploop;
129	d->curserver = 0;
130	}
131
132	dns_transmit_free(d); return -1;
133	}
134
135	static int firstudp(struct dns_transmit *d)
136	{
137	d->curserver = 0;
138	return thisudp(d);
139	}
140
141	static int nextudp(struct dns_transmit *d)
142	{
143	++d->curserver;
144	return thisudp(d);
145	}
146
147	static int thistcp(struct dns_transmit *d)
148	{
149	struct taia now;
150	const char *ip;
151
152	socketfree(d);
153	packetfree(d);
154
155	for (;d->curserver < 16;++d->curserver) {
156	ip = d->servers + 4 * d->curserver;
157	if (byte_diff(ip,4,"\0\0\0\0")) {
158	d->query[2] = dns_random(256);
159	d->query[3] = dns_random(256);
160
161	d->s1 = 1 + socket_tcp();
162	if (!d->s1) { dns_transmit_free(d); return -1; }
163	if (randombind(d) == -1) { dns_transmit_free(d); return -1; }
164
165	taia_now(&now);
166	taia_uint(&d->deadline,10);
167	taia_add(&d->deadline,&d->deadline,&now);
168	if (socket_connect4(d->s1 - 1,ip,53) == 0) {
169	d->tcpstate = 2;
170	return 0;
171	}
172	if ((errno == error_inprogress) \|\| (errno == error_wouldblock)) {
173	d->tcpstate = 1;
174	return 0;
175	}
176
177	socketfree(d);
178	}
179	}
180
181	dns_transmit_free(d); return -1;
182	}
183
184	static int firsttcp(struct dns_transmit *d)
185	{
186	d->curserver = 0;
187	return thistcp(d);
188	}
189
190	static int nexttcp(struct dns_transmit *d)
191	{
192	++d->curserver;
193	return thistcp(d);
194	}
195
196	int dns_transmit_start(struct dns_transmit d,const char servers[64],int flagrecursive,const char q,const char qtype[2],const char localip[4])
197	{
198	unsigned int len;
199
200	dns_transmit_free(d);
201	errno = error_io;
202
203	len = dns_domain_length(q);
204	d->querylen = len + 18;
205	d->query = alloc(d->querylen);
206	if (!d->query) return -1;
207
208	uint16_pack_big(d->query,len + 16);
209	byte_copy(d->query + 2,12,flagrecursive ? "\0\0\1\0\0\1\0\0\0\0\0\0" : "\0\0\0\0\0\1\0\0\0\0\0\0gcc-bug-workaround");
210	byte_copy(d->query + 14,len,q);
211	byte_copy(d->query + 14 + len,2,qtype);
212	byte_copy(d->query + 16 + len,2,DNS_C_IN);
213
214	byte_copy(d->qtype,2,qtype);
215	d->servers = servers;
216	byte_copy(d->localip,4,localip);
217
218	d->udploop = flagrecursive ? 1 : 0;
219
220	if (len + 16 > 512) return firsttcp(d);
221	return firstudp(d);
222	}
223
224	void dns_transmit_io(struct dns_transmit d,iopause_fd x,struct taia *deadline)
225	{
226	x->fd = d->s1 - 1;
227
228	switch(d->tcpstate) {
229	case 0: case 3: case 4: case 5:
230	x->events = IOPAUSE_READ;
231	break;
232	case 1: case 2:
233	x->events = IOPAUSE_WRITE;
234	break;
235	}
236
237	if (taia_less(&d->deadline,deadline))
238	*deadline = d->deadline;
239	}
240
241	int dns_transmit_get(struct dns_transmit d,const iopause_fd x,const struct taia *when)
242	{
243	char udpbuf[513];
244	unsigned char ch;
245	int r;
246	int fd;
247
248	errno = error_io;
249	fd = d->s1 - 1;
250
251	if (!x->revents) {
252	if (taia_less(when,&d->deadline)) return 0;
253	errno = error_timeout;
254	if (d->tcpstate == 0) return nextudp(d);
255	return nexttcp(d);
256	}
257
258	if (d->tcpstate == 0) {
259	/*
260	have attempted to send UDP query to each server udploop times
261	have sent query to curserver on UDP socket s
262	*/
263	r = recv(fd,udpbuf,sizeof udpbuf,0);
264	if (r <= 0) {
265	if (errno == error_connrefused) if (d->udploop == 2) return 0;
266	return nextudp(d);
267	}
268	if (r + 1 > sizeof udpbuf) return 0;
269
270	if (irrelevant(d,udpbuf,r)) return 0;
271	if (serverwantstcp(udpbuf,r)) return firsttcp(d);
272	if (serverfailed(udpbuf,r)) {
273	if (d->udploop == 2) return 0;
274	return nextudp(d);
275	}
276	socketfree(d);
277
278	d->packetlen = r;
279	d->packet = alloc(d->packetlen);
280	if (!d->packet) { dns_transmit_free(d); return -1; }
281	byte_copy(d->packet,d->packetlen,udpbuf);
282	queryfree(d);
283	return 1;
284	}
285
286	if (d->tcpstate == 1) {
287	/*
288	have sent connection attempt to curserver on TCP socket s
289	pos not defined
290	*/
291	if (!socket_connected(fd)) return nexttcp(d);
292	d->pos = 0;
293	d->tcpstate = 2;
294	return 0;
295	}
296
297	if (d->tcpstate == 2) {
298	/*
299	have connection to curserver on TCP socket s
300	have sent pos bytes of query
301	*/
302	r = write(fd,d->query + d->pos,d->querylen - d->pos);
303	if (r <= 0) return nexttcp(d);
304	d->pos += r;
305	if (d->pos == d->querylen) {
306	struct taia now;
307	taia_now(&now);
308	taia_uint(&d->deadline,10);
309	taia_add(&d->deadline,&d->deadline,&now);
310	d->tcpstate = 3;
311	}
312	return 0;
313	}
314
315	if (d->tcpstate == 3) {
316	/*
317	have sent entire query to curserver on TCP socket s
318	pos not defined
319	*/
320	r = read(fd,&ch,1);
321	if (r <= 0) return nexttcp(d);
322	d->packetlen = ch;
323	d->tcpstate = 4;
324	return 0;
325	}
326
327	if (d->tcpstate == 4) {
328	/*
329	have sent entire query to curserver on TCP socket s
330	pos not defined
331	have received one byte of packet length into packetlen
332	*/
333	r = read(fd,&ch,1);
334	if (r <= 0) return nexttcp(d);
335	d->packetlen <<= 8;
336	d->packetlen += ch;
337	d->tcpstate = 5;
338	d->pos = 0;
339	d->packet = alloc(d->packetlen);
340	if (!d->packet) { dns_transmit_free(d); return -1; }
341	return 0;
342	}
343
344	if (d->tcpstate == 5) {
345	/*
346	have sent entire query to curserver on TCP socket s
347	have received entire packet length into packetlen
348	packet is allocated
349	have received pos bytes of packet
350	*/
351	r = read(fd,d->packet + d->pos,d->packetlen - d->pos);
352	if (r <= 0) return nexttcp(d);
353	d->pos += r;
354	if (d->pos < d->packetlen) return 0;
355
356	socketfree(d);
357	if (irrelevant(d,d->packet,d->packetlen)) return nexttcp(d);
358	if (serverwantstcp(d->packet,d->packetlen)) return nexttcp(d);
359	if (serverfailed(d->packet,d->packetlen)) return nexttcp(d);
360
361	queryfree(d);
362	return 1;
363	}
364
365	return 0;
366	}