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ldb: Release ldb 2.2.1
[Samba.git] / ctdb / common / system_socket.c
blobbb513508353ee21d239f02664c2cde5d6897e604
1 /*
2 ctdb system specific code to manage raw sockets on linux
3
4 Copyright (C) Ronnie Sahlberg 2007
5 Copyright (C) Andrew Tridgell 2007
6 Copyright (C) Marc Dequènes (Duck) 2009
7 Copyright (C) Volker Lendecke 2012
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, see <http://www.gnu.org/licenses/>.
21 */
22
23 #include "replace.h"
24
25 /*
26 * Use BSD struct tcphdr field names for portability. Modern glibc
27 * makes them available by default via <netinet/tcp.h> but older glibc
28 * requires __FAVOR_BSD to be defined.
29 *
30 * __FAVOR_BSD is normally defined in <features.h> if _DEFAULT_SOURCE
31 * (new) or _BSD_SOURCE (now deprecated) is set and _GNU_SOURCE is not
32 * set. Including "replace.h" above causes <features.h> to be
33 * indirectly included and this will not set __FAVOR_BSD because
34 * _GNU_SOURCE is set in Samba's "config.h" (which is included by
35 * "replace.h").
36 *
37 * Therefore, set __FAVOR_BSD by hand below.
38 */
39 #define __FAVOR_BSD 1
40 #include "system/network.h"
41
42 #ifdef HAVE_NETINET_IF_ETHER_H
43 #include <netinet/if_ether.h>
44 #endif
45 #ifdef HAVE_NETINET_IP6_H
46 #include <netinet/ip6.h>
47 #endif
48 #ifdef HAVE_NETINET_ICMP6_H
49 #include <netinet/icmp6.h>
50 #endif
51 #ifdef HAVE_LINUX_IF_PACKET_H
52 #include <linux/if_packet.h>
53 #endif
54
55 #ifndef ETHERTYPE_IP6
56 #define ETHERTYPE_IP6 0x86dd
57 #endif
58
59 #include "lib/util/debug.h"
60 #include "lib/util/blocking.h"
61
62 #include "protocol/protocol.h"
63
64 #include "common/logging.h"
65 #include "common/system_socket.h"
66
67 /*
68 uint16 checksum for n bytes
69 */
70 static uint32_t uint16_checksum(uint8_t *data, size_t n)
71 {
72 uint32_t sum=0;
73 uint16_t value;
74
75 while (n>=2) {
76 memcpy(&value, data, 2);
77 sum += (uint32_t)ntohs(value);
78 data += 2;
79 n -= 2;
80 }
81 if (n == 1) {
82 sum += (uint32_t)ntohs(*data);
83 }
84 return sum;
85 }
86
87 /*
88 * See if the given IP is currently on an interface
89 */
90 bool ctdb_sys_have_ip(ctdb_sock_addr *_addr)
91 {
92 int s;
93 int ret;
94 ctdb_sock_addr __addr = *_addr;
95 ctdb_sock_addr *addr = &__addr;
96 socklen_t addrlen = 0;
97
98 switch (addr->sa.sa_family) {
99 case AF_INET:
100 addr->ip.sin_port = 0;
101 addrlen = sizeof(struct sockaddr_in);
102 break;
103 case AF_INET6:
104 addr->ip6.sin6_port = 0;
105 addrlen = sizeof(struct sockaddr_in6);
106 break;
107 }
108
109 s = socket(addr->sa.sa_family, SOCK_STREAM, IPPROTO_TCP);
110 if (s == -1) {
111 return false;
112 }
113
114 ret = bind(s, (struct sockaddr *)addr, addrlen);
115
116 close(s);
117 return ret == 0;
118 }
119
120 /*
121 * simple TCP checksum - assumes data is multiple of 2 bytes long
122 */
123 static uint16_t ip_checksum(uint8_t *data, size_t n, struct ip *ip)
124 {
125 uint32_t sum = uint16_checksum(data, n);
126 uint16_t sum2;
127
128 sum += uint16_checksum((uint8_t *)&ip->ip_src, sizeof(ip->ip_src));
129 sum += uint16_checksum((uint8_t *)&ip->ip_dst, sizeof(ip->ip_dst));
130 sum += ip->ip_p + n;
131 sum = (sum & 0xFFFF) + (sum >> 16);
132 sum = (sum & 0xFFFF) + (sum >> 16);
133 sum2 = htons(sum);
134 sum2 = ~sum2;
135 if (sum2 == 0) {
136 return 0xFFFF;
137 }
138 return sum2;
139 }
140
141 static uint16_t ip6_checksum(uint8_t *data, size_t n, struct ip6_hdr *ip6)
142 {
143 uint16_t phdr[3];
144 uint32_t sum = 0;
145 uint16_t sum2;
146 uint32_t len;
147
148 sum += uint16_checksum((uint8_t *)&ip6->ip6_src, 16);
149 sum += uint16_checksum((uint8_t *)&ip6->ip6_dst, 16);
150
151 len = htonl(n);
152 phdr[0] = len & UINT16_MAX;
153 phdr[1] = (len >> 16) & UINT16_MAX;
154 /* ip6_nxt is only 8 bits, so fits comfortably into a uint16_t */
155 phdr[2] = htons(ip6->ip6_nxt);
156 sum += uint16_checksum((uint8_t *)phdr, sizeof(phdr));
157
158 sum += uint16_checksum(data, n);
159
160 sum = (sum & 0xFFFF) + (sum >> 16);
161 sum = (sum & 0xFFFF) + (sum >> 16);
162 sum2 = htons(sum);
163 sum2 = ~sum2;
164 if (sum2 == 0) {
165 return 0xFFFF;
166 }
167 return sum2;
168 }
169
170 /*
171 * Send gratuitous ARP request/reply or IPv6 neighbor advertisement
172 */
173
174 #ifdef HAVE_PACKETSOCKET
175
176 /*
177 * Create IPv4 ARP requests/replies or IPv6 neighbour advertisement
178 * packets
179 */
180
181 #define ARP_STRUCT_SIZE sizeof(struct ether_header) + \
182 sizeof(struct ether_arp)
183
184 #define IP6_NA_STRUCT_SIZE sizeof(struct ether_header) + \
185 sizeof(struct ip6_hdr) + \
186 sizeof(struct nd_neighbor_advert) + \
187 sizeof(struct nd_opt_hdr) + \
188 sizeof(struct ether_addr)
189
190 #define ARP_BUFFER_SIZE MAX(ARP_STRUCT_SIZE, 64)
191
192 #define IP6_NA_BUFFER_SIZE MAX(IP6_NA_STRUCT_SIZE, 64)
193
194 static int arp_build(uint8_t *buffer,
195 size_t buflen,
196 const struct sockaddr_in *addr,
197 const struct ether_addr *hwaddr,
198 bool reply,
199 struct ether_addr **ether_dhost,
200 size_t *len)
201 {
202 size_t l = ARP_BUFFER_SIZE;
203 struct ether_header *eh;
204 struct ether_arp *ea;
205 struct arphdr *ah;
206
207 if (addr->sin_family != AF_INET) {
208 return EINVAL;
209 }
210
211 if (buflen < l) {
212 return EMSGSIZE;
213 }
214
215 memset(buffer, 0 , l);
216
217 eh = (struct ether_header *)buffer;
218 memset(eh->ether_dhost, 0xff, ETH_ALEN);
219 memcpy(eh->ether_shost, hwaddr, ETH_ALEN);
220 eh->ether_type = htons(ETHERTYPE_ARP);
221
222 ea = (struct ether_arp *)(buffer + sizeof(struct ether_header));
223 ah = &ea->ea_hdr;
224 ah->ar_hrd = htons(ARPHRD_ETHER);
225 ah->ar_pro = htons(ETH_P_IP);
226 ah->ar_hln = ETH_ALEN;
227 ah->ar_pln = sizeof(ea->arp_spa);
228
229 if (! reply) {
230 ah->ar_op = htons(ARPOP_REQUEST);
231 memcpy(ea->arp_sha, hwaddr, ETH_ALEN);
232 memcpy(ea->arp_spa, &addr->sin_addr, sizeof(ea->arp_spa));
233 memset(ea->arp_tha, 0, ETH_ALEN);
234 memcpy(ea->arp_tpa, &addr->sin_addr, sizeof(ea->arp_tpa));
235 } else {
236 ah->ar_op = htons(ARPOP_REPLY);
237 memcpy(ea->arp_sha, hwaddr, ETH_ALEN);
238 memcpy(ea->arp_spa, &addr->sin_addr, sizeof(ea->arp_spa));
239 memcpy(ea->arp_tha, hwaddr, ETH_ALEN);
240 memcpy(ea->arp_tpa, &addr->sin_addr, sizeof(ea->arp_tpa));
241 }
242
243 *ether_dhost = (struct ether_addr *)eh->ether_dhost;
244 *len = l;
245 return 0;
246 }
247
248 static int ip6_na_build(uint8_t *buffer,
249 size_t buflen,
250 const struct sockaddr_in6 *addr,
251 const struct ether_addr *hwaddr,
252 struct ether_addr **ether_dhost,
253 size_t *len)
254 {
255 size_t l = IP6_NA_BUFFER_SIZE;
256 struct ether_header *eh;
257 struct ip6_hdr *ip6;
258 struct nd_neighbor_advert *nd_na;
259 struct nd_opt_hdr *nd_oh;
260 struct ether_addr *ea;
261 int ret;
262
263 if (addr->sin6_family != AF_INET6) {
264 return EINVAL;
265 }
266
267 if (buflen < l) {
268 return EMSGSIZE;
269 }
270
271 memset(buffer, 0 , l);
272
273 eh = (struct ether_header *)buffer;
274 /*
275 * Ethernet multicast: 33:33:00:00:00:01 (see RFC2464,
276 * section 7) - note memset 0 above!
277 */
278 eh->ether_dhost[0] = 0x33;
279 eh->ether_dhost[1] = 0x33;
280 eh->ether_dhost[5] = 0x01;
281 memcpy(eh->ether_shost, hwaddr, ETH_ALEN);
282 eh->ether_type = htons(ETHERTYPE_IP6);
283
284 ip6 = (struct ip6_hdr *)(buffer + sizeof(struct ether_header));
285 ip6->ip6_vfc = 6 << 4;
286 ip6->ip6_plen = htons(sizeof(struct nd_neighbor_advert) +
287 sizeof(struct nd_opt_hdr) +
288 ETH_ALEN);
289 ip6->ip6_nxt = IPPROTO_ICMPV6;
290 ip6->ip6_hlim = 255;
291 ip6->ip6_src = addr->sin6_addr;
292 /* all-nodes multicast */
293
294 ret = inet_pton(AF_INET6, "ff02::1", &ip6->ip6_dst);
295 if (ret != 1) {
296 return EIO;
297 }
298
299 nd_na = (struct nd_neighbor_advert *)(buffer +
300 sizeof(struct ether_header) +
301 sizeof(struct ip6_hdr));
302 nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
303 nd_na->nd_na_code = 0;
304 nd_na->nd_na_flags_reserved = ND_NA_FLAG_OVERRIDE;
305 nd_na->nd_na_target = addr->sin6_addr;
306
307 /* Option: Target link-layer address */
308 nd_oh = (struct nd_opt_hdr *)(buffer +
309 sizeof(struct ether_header) +
310 sizeof(struct ip6_hdr) +
311 sizeof(struct nd_neighbor_advert));
312 nd_oh->nd_opt_type = ND_OPT_TARGET_LINKADDR;
313 nd_oh->nd_opt_len = 1; /* multiple of 8 octets */
314
315 ea = (struct ether_addr *)(buffer +
316 sizeof(struct ether_header) +
317 sizeof(struct ip6_hdr) +
318 sizeof(struct nd_neighbor_advert) +
319 sizeof(struct nd_opt_hdr));
320 memcpy(ea, hwaddr, ETH_ALEN);
321
322 nd_na->nd_na_cksum = ip6_checksum((uint8_t *)nd_na,
323 ntohs(ip6->ip6_plen),
324 ip6);
325
326 *ether_dhost = (struct ether_addr *)eh->ether_dhost;
327 *len = l;
328 return 0;
329 }
330
331 int ctdb_sys_send_arp(const ctdb_sock_addr *addr, const char *iface)
332 {
333 int s;
334 struct sockaddr_ll sall = {0};
335 struct ifreq if_hwaddr = {
336 .ifr_ifru = {
337 .ifru_flags = 0
338 },
339 };
340 uint8_t buffer[MAX(ARP_BUFFER_SIZE, IP6_NA_BUFFER_SIZE)];
341 struct ifreq ifr = {
342 .ifr_ifru = {
343 .ifru_flags = 0
344 },
345 };
346 struct ether_addr *hwaddr = NULL;
347 struct ether_addr *ether_dhost = NULL;
348 size_t len = 0;
349 int ret = 0;
350
351 s = socket(AF_PACKET, SOCK_RAW, 0);
352 if (s == -1) {
353 ret = errno;
354 DBG_ERR("Failed to open raw socket\n");
355 return ret;
356 }
357 DBG_DEBUG("Created SOCKET FD:%d for sending arp\n", s);
358
359 /* Find interface */
360 strlcpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name));
361 if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
362 ret = errno;
363 DBG_ERR("Interface '%s' not found\n", iface);
364 goto fail;
365 }
366
367 /* Get MAC address */
368 strlcpy(if_hwaddr.ifr_name, iface, sizeof(if_hwaddr.ifr_name));
369 ret = ioctl(s, SIOCGIFHWADDR, &if_hwaddr);
370 if ( ret < 0 ) {
371 ret = errno;
372 DBG_ERR("ioctl failed\n");
373 goto fail;
374 }
375 if (ARPHRD_LOOPBACK == if_hwaddr.ifr_hwaddr.sa_family) {
376 ret = 0;
377 D_DEBUG("Ignoring loopback arp request\n");
378 goto fail;
379 }
380 if (if_hwaddr.ifr_hwaddr.sa_family != ARPHRD_ETHER) {
381 ret = EINVAL;
382 DBG_ERR("Not an ethernet address family (0x%x)\n",
383 if_hwaddr.ifr_hwaddr.sa_family);
384 goto fail;;
385 }
386
387 /* Set up most of destination address structure */
388 sall.sll_family = AF_PACKET;
389 sall.sll_halen = sizeof(struct ether_addr);
390 sall.sll_protocol = htons(ETH_P_ALL);
391 sall.sll_ifindex = ifr.ifr_ifindex;
392
393 /* For clarity */
394 hwaddr = (struct ether_addr *)if_hwaddr.ifr_hwaddr.sa_data;
395
396 switch (addr->ip.sin_family) {
397 case AF_INET:
398 /* Send gratuitous ARP */
399 ret = arp_build(buffer,
400 sizeof(buffer),
401 &addr->ip,
402 hwaddr,
403 false,
404 &ether_dhost,
405 &len);
406 if (ret != 0) {
407 DBG_ERR("Failed to build ARP request\n");
408 goto fail;
409 }
410
411 memcpy(&sall.sll_addr[0], ether_dhost, sall.sll_halen);
412
413 ret = sendto(s,
414 buffer,
415 len,
416 0,
417 (struct sockaddr *)&sall,
418 sizeof(sall));
419 if (ret < 0 ) {
420 ret = errno;
421 DBG_ERR("Failed sendto\n");
422 goto fail;
423 }
424
425 /* Send unsolicited ARP reply */
426 ret = arp_build(buffer,
427 sizeof(buffer),
428 &addr->ip,
429 hwaddr,
430 true,
431 &ether_dhost,
432 &len);
433 if (ret != 0) {
434 DBG_ERR("Failed to build ARP reply\n");
435 goto fail;
436 }
437
438 memcpy(&sall.sll_addr[0], ether_dhost, sall.sll_halen);
439
440 ret = sendto(s,
441 buffer,
442 len,
443 0,
444 (struct sockaddr *)&sall,
445 sizeof(sall));
446 if (ret < 0 ) {
447 ret = errno;
448 DBG_ERR("Failed sendto\n");
449 goto fail;
450 }
451
452 close(s);
453 break;
454
455 case AF_INET6:
456 ret = ip6_na_build(buffer,
457 sizeof(buffer),
458 &addr->ip6,
459 hwaddr,
460 &ether_dhost,
461 &len);
462 if (ret != 0) {
463 DBG_ERR("Failed to build IPv6 neighbor advertisement\n");
464 goto fail;
465 }
466
467 memcpy(&sall.sll_addr[0], ether_dhost, sall.sll_halen);
468
469 ret = sendto(s,
470 buffer,
471 len,
472 0,
473 (struct sockaddr *)&sall,
474 sizeof(sall));
475 if (ret < 0 ) {
476 ret = errno;
477 DBG_ERR("Failed sendto\n");
478 goto fail;
479 }
480
481 close(s);
482 break;
483
484 default:
485 ret = EINVAL;
486 DBG_ERR("Not an ipv4/ipv6 address (family is %u)\n",
487 addr->ip.sin_family);
488 goto fail;
489 }
490
491 return 0;
492
493 fail:
494 close(s);
495 return ret;
496 }
497
498 #else /* HAVE_PACKETSOCKET */
499
500 int ctdb_sys_send_arp(const ctdb_sock_addr *addr, const char *iface)
501 {
502 /* Not implemented */
503 return ENOSYS;
504 }
505
506 #endif /* HAVE_PACKETSOCKET */
507
508
509 #define IP4_TCP_BUFFER_SIZE sizeof(struct ip) + \
510 sizeof(struct tcphdr)
511
512 #define IP6_TCP_BUFFER_SIZE sizeof(struct ip6_hdr) + \
513 sizeof(struct tcphdr)
514
515 static int tcp4_build(uint8_t *buf,
516 size_t buflen,
517 const struct sockaddr_in *src,
518 const struct sockaddr_in *dst,
519 uint32_t seq,
520 uint32_t ack,
521 int rst,
522 size_t *len)
523 {
524 size_t l = IP4_TCP_BUFFER_SIZE;
525 struct {
526 struct ip ip;
527 struct tcphdr tcp;
528 } *ip4pkt;
529
530 if (l != sizeof(*ip4pkt)) {
531 return EMSGSIZE;
532 }
533
534 if (buflen < l) {
535 return EMSGSIZE;
536 }
537
538 ip4pkt = (void *)buf;
539 memset(ip4pkt, 0, l);
540
541 ip4pkt->ip.ip_v = 4;
542 ip4pkt->ip.ip_hl = sizeof(ip4pkt->ip)/sizeof(uint32_t);
543 ip4pkt->ip.ip_len = htons(sizeof(ip4pkt));
544 ip4pkt->ip.ip_ttl = 255;
545 ip4pkt->ip.ip_p = IPPROTO_TCP;
546 ip4pkt->ip.ip_src.s_addr = src->sin_addr.s_addr;
547 ip4pkt->ip.ip_dst.s_addr = dst->sin_addr.s_addr;
548 ip4pkt->ip.ip_sum = 0;
549
550 ip4pkt->tcp.th_sport = src->sin_port;
551 ip4pkt->tcp.th_dport = dst->sin_port;
552 ip4pkt->tcp.th_seq = seq;
553 ip4pkt->tcp.th_ack = ack;
554 ip4pkt->tcp.th_flags = 0;
555 ip4pkt->tcp.th_flags |= TH_ACK;
556 if (rst) {
557 ip4pkt->tcp.th_flags |= TH_RST;
558 }
559 ip4pkt->tcp.th_off = sizeof(ip4pkt->tcp)/sizeof(uint32_t);
560 /* this makes it easier to spot in a sniffer */
561 ip4pkt->tcp.th_win = htons(1234);
562 ip4pkt->tcp.th_sum = ip_checksum((uint8_t *)&ip4pkt->tcp,
563 sizeof(ip4pkt->tcp),
564 &ip4pkt->ip);
565
566 *len = l;
567 return 0;
568 }
569
570 static int tcp6_build(uint8_t *buf,
571 size_t buflen,
572 const struct sockaddr_in6 *src,
573 const struct sockaddr_in6 *dst,
574 uint32_t seq,
575 uint32_t ack,
576 int rst,
577 size_t *len)
578 {
579 size_t l = IP6_TCP_BUFFER_SIZE;
580 struct {
581 struct ip6_hdr ip6;
582 struct tcphdr tcp;
583 } *ip6pkt;
584
585 if (l != sizeof(*ip6pkt)) {
586 return EMSGSIZE;
587 }
588
589 if (buflen < l) {
590 return EMSGSIZE;
591 }
592
593 ip6pkt = (void *)buf;
594 memset(ip6pkt, 0, l);
595
596 ip6pkt->ip6.ip6_vfc = 6 << 4;
597 ip6pkt->ip6.ip6_plen = htons(sizeof(struct tcphdr));
598 ip6pkt->ip6.ip6_nxt = IPPROTO_TCP;
599 ip6pkt->ip6.ip6_hlim = 64;
600 ip6pkt->ip6.ip6_src = src->sin6_addr;
601 ip6pkt->ip6.ip6_dst = dst->sin6_addr;
602
603 ip6pkt->tcp.th_sport = src->sin6_port;
604 ip6pkt->tcp.th_dport = dst->sin6_port;
605 ip6pkt->tcp.th_seq = seq;
606 ip6pkt->tcp.th_ack = ack;
607 ip6pkt->tcp.th_flags = 0;
608 ip6pkt->tcp.th_flags |= TH_ACK;
609 if (rst) {
610 ip6pkt->tcp.th_flags |= TH_RST;
611 }
612 ip6pkt->tcp.th_off = sizeof(ip6pkt->tcp)/sizeof(uint32_t);
613 /* this makes it easier to spot in a sniffer */
614 ip6pkt->tcp.th_win = htons(1234);
615 ip6pkt->tcp.th_sum = ip6_checksum((uint8_t *)&ip6pkt->tcp,
616 sizeof(ip6pkt->tcp),
617 &ip6pkt->ip6);
618
619 *len = l;
620 return 0;
621 }
622
623 /*
624 * Send tcp segment from the specified IP/port to the specified
625 * destination IP/port.
626 *
627 * This is used to trigger the receiving host into sending its own ACK,
628 * which should trigger early detection of TCP reset by the client
629 * after IP takeover
630 *
631 * This can also be used to send RST segments (if rst is true) and also
632 * if correct seq and ack numbers are provided.
633 */
634 int ctdb_sys_send_tcp(const ctdb_sock_addr *dest,
635 const ctdb_sock_addr *src,
636 uint32_t seq,
637 uint32_t ack,
638 int rst)
639 {
640 uint8_t buf[MAX(IP4_TCP_BUFFER_SIZE, IP6_TCP_BUFFER_SIZE)];
641 size_t len = 0;
642 int ret;
643 int s;
644 uint32_t one = 1;
645 struct sockaddr_in6 tmpdest = { 0 };
646 int saved_errno;
647
648 switch (src->ip.sin_family) {
649 case AF_INET:
650 ret = tcp4_build(buf,
651 sizeof(buf),
652 &src->ip,
653 &dest->ip,
654 seq,
655 ack,
656 rst,
657 &len);
658 if (ret != 0) {
659 DBG_ERR("Failed to build TCP packet (%d)\n", ret);
660 return ret;
661 }
662
663 /* open a raw socket to send this segment from */
664 s = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
665 if (s == -1) {
666 DBG_ERR("Failed to open raw socket (%s)\n",
667 strerror(errno));
668 return -1;
669 }
670
671 ret = setsockopt(s, IPPROTO_IP, IP_HDRINCL, &one, sizeof(one));
672 if (ret != 0) {
673 DBG_ERR("Failed to setup IP headers (%s)\n",
674 strerror(errno));
675 close(s);
676 return -1;
677 }
678
679 ret = sendto(s,
680 buf,
681 len,
682 0,
683 (const struct sockaddr *)&dest->ip,
684 sizeof(dest->ip));
685 saved_errno = errno;
686 close(s);
687 if (ret == -1) {
688 D_ERR("Failed sendto (%s)\n", strerror(saved_errno));
689 return -1;
690 }
691 if ((size_t)ret != len) {
692 DBG_ERR("Failed sendto - didn't send full packet\n");
693 return -1;
694 }
695 break;
696
697 case AF_INET6:
698 ret = tcp6_build(buf,
699 sizeof(buf),
700 &src->ip6,
701 &dest->ip6,
702 seq,
703 ack,
704 rst,
705 &len);
706 if (ret != 0) {
707 DBG_ERR("Failed to build TCP packet (%d)\n", ret);
708 return ret;
709 }
710
711 s = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW);
712 if (s == -1) {
713 DBG_ERR("Failed to open sending socket\n");
714 return -1;
715
716 }
717 /*
718 * sendto() on an IPv6 raw socket requires the port to
719 * be either 0 or a protocol value
720 */
721 tmpdest = dest->ip6;
722 tmpdest.sin6_port = 0;
723
724 ret = sendto(s,
725 buf,
726 len,
727 0,
728 (const struct sockaddr *)&tmpdest,
729 sizeof(tmpdest));
730 saved_errno = errno;
731 close(s);
732 if (ret == -1) {
733 D_ERR("Failed sendto (%s)\n", strerror(saved_errno));
734 return -1;
735 }
736 if ((size_t)ret != len) {
737 DBG_ERR("Failed sendto - didn't send full packet\n");
738 return -1;
739 }
740 break;
741
742 default:
743 DBG_ERR("Not an ipv4/v6 address\n");
744 return -1;
745 }
746
747 return 0;
748 }
749
750 /*
751 * Packet capture
752 *
753 * If AF_PACKET is available then use a raw socket otherwise use pcap.
754 * wscript has checked to make sure that pcap is available if needed.
755 */
756
757 static int tcp4_extract(const uint8_t *ip_pkt,
758 size_t pktlen,
759 struct sockaddr_in *src,
760 struct sockaddr_in *dst,
761 uint32_t *ack_seq,
762 uint32_t *seq,
763 int *rst,
764 uint16_t *window)
765 {
766 const struct ip *ip;
767 const struct tcphdr *tcp;
768
769 if (pktlen < sizeof(struct ip)) {
770 return EMSGSIZE;
771 }
772
773 ip = (const struct ip *)ip_pkt;
774
775 /* IPv4 only */
776 if (ip->ip_v != 4) {
777 return ENOMSG;
778 }
779 /* Don't look at fragments */
780 if ((ntohs(ip->ip_off)&0x1fff) != 0) {
781 return ENOMSG;
782 }
783 /* TCP only */
784 if (ip->ip_p != IPPROTO_TCP) {
785 return ENOMSG;
786 }
787
788 /* Ensure there is enough of the packet to gather required fields */
789 if (pktlen <
790 (ip->ip_hl * sizeof(uint32_t)) + offsetof(struct tcphdr, th_sum)) {
791 return EMSGSIZE;
792 }
793
794 tcp = (const struct tcphdr *)(ip_pkt + (ip->ip_hl * sizeof(uint32_t)));
795
796 src->sin_family = AF_INET;
797 src->sin_addr.s_addr = ip->ip_src.s_addr;
798 src->sin_port = tcp->th_sport;
799
800 dst->sin_family = AF_INET;
801 dst->sin_addr.s_addr = ip->ip_dst.s_addr;
802 dst->sin_port = tcp->th_dport;
803
804 *ack_seq = tcp->th_ack;
805 *seq = tcp->th_seq;
806 if (window != NULL) {
807 *window = tcp->th_win;
808 }
809 if (rst != NULL) {
810 *rst = tcp->th_flags & TH_RST;
811 }
812
813 return 0;
814 }
815
816 static int tcp6_extract(const uint8_t *ip_pkt,
817 size_t pktlen,
818 struct sockaddr_in6 *src,
819 struct sockaddr_in6 *dst,
820 uint32_t *ack_seq,
821 uint32_t *seq,
822 int *rst,
823 uint16_t *window)
824 {
825 const struct ip6_hdr *ip6;
826 const struct tcphdr *tcp;
827
828 /* Ensure there is enough of the packet to gather required fields */
829 if (pktlen < sizeof(struct ip6_hdr) + offsetof(struct tcphdr, th_sum)) {
830 return EMSGSIZE;
831 }
832
833 ip6 = (const struct ip6_hdr *)ip_pkt;
834
835 /* IPv6 only */
836 if ((ip6->ip6_vfc >> 4) != 6){
837 return ENOMSG;
838 }
839
840 /* TCP only */
841 if (ip6->ip6_nxt != IPPROTO_TCP) {
842 return ENOMSG;
843 }
844
845 tcp = (const struct tcphdr *)(ip_pkt + sizeof(struct ip6_hdr));
846
847 src->sin6_family = AF_INET6;
848 src->sin6_port = tcp->th_sport;
849 src->sin6_addr = ip6->ip6_src;
850
851 dst->sin6_family = AF_INET6;
852 dst->sin6_port = tcp->th_dport;
853 dst->sin6_addr = ip6->ip6_dst;
854
855 *ack_seq = tcp->th_ack;
856 *seq = tcp->th_seq;
857 if (window != NULL) {
858 *window = tcp->th_win;
859 }
860 if (rst != NULL) {
861 *rst = tcp->th_flags & TH_RST;
862 }
863
864 return 0;
865 }
866
867
868 #ifdef HAVE_AF_PACKET
869
870 /*
871 * This function is used to open a raw socket to capture from
872 */
873 int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
874 {
875 int s, ret;
876
877 /* Open a socket to capture all traffic */
878 s = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
879 if (s == -1) {
880 DBG_ERR("Failed to open raw socket\n");
881 return -1;
882 }
883
884 DBG_DEBUG("Created RAW SOCKET FD:%d for tcp tickle\n", s);
885
886 ret = set_blocking(s, false);
887 if (ret != 0) {
888 DBG_ERR("Failed to set socket non-blocking (%s)\n",
889 strerror(errno));
890 close(s);
891 return -1;
892 }
893
894 set_close_on_exec(s);
895
896 return s;
897 }
898
899 /*
900 * This function is used to do any additional cleanup required when closing
901 * a capture socket.
902 * Note that the socket itself is closed automatically in the caller.
903 */
904 int ctdb_sys_close_capture_socket(void *private_data)
905 {
906 return 0;
907 }
908
909
910 /*
911 * called when the raw socket becomes readable
912 */
913 int ctdb_sys_read_tcp_packet(int s, void *private_data,
914 ctdb_sock_addr *src,
915 ctdb_sock_addr *dst,
916 uint32_t *ack_seq,
917 uint32_t *seq,
918 int *rst,
919 uint16_t *window)
920 {
921 ssize_t nread;
922 uint8_t pkt[100]; /* Large enough for simple ACK/RST packets */
923 struct ether_header *eth;
924 int ret;
925
926 nread = recv(s, pkt, sizeof(pkt), MSG_TRUNC);
927 if (nread == -1) {
928 return errno;
929 }
930 if ((size_t)nread < sizeof(*eth)) {
931 return EMSGSIZE;
932 }
933
934 ZERO_STRUCTP(src);
935 ZERO_STRUCTP(dst);
936
937 /* Ethernet */
938 eth = (struct ether_header *)pkt;
939
940 /* we want either IPv4 or IPv6 */
941 if (ntohs(eth->ether_type) == ETHERTYPE_IP) {
942 ret = tcp4_extract(pkt + sizeof(struct ether_header),
943 (size_t)nread - sizeof(struct ether_header),
944 &src->ip,
945 &dst->ip,
946 ack_seq,
947 seq,
948 rst,
949 window);
950 return ret;
951
952 } else if (ntohs(eth->ether_type) == ETHERTYPE_IP6) {
953 ret = tcp6_extract(pkt + sizeof(struct ether_header),
954 (size_t)nread - sizeof(struct ether_header),
955 &src->ip6,
956 &dst->ip6,
957 ack_seq,
958 seq,
959 rst,
960 window);
961 return ret;
962 }
963
964 return ENOMSG;
965 }
966
967 #else /* HAVE_AF_PACKET */
968
969 #include <pcap.h>
970
971 int ctdb_sys_open_capture_socket(const char *iface, void **private_data)
972 {
973 pcap_t *pt;
974
975 pt=pcap_open_live(iface, 100, 0, 0, NULL);
976 if (pt == NULL) {
977 DBG_ERR("Failed to open capture device %s\n", iface);
978 return -1;
979 }
980 *((pcap_t **)private_data) = pt;
981
982 return pcap_fileno(pt);
983 }
984
985 int ctdb_sys_close_capture_socket(void *private_data)
986 {
987 pcap_t *pt = (pcap_t *)private_data;
988 pcap_close(pt);
989 return 0;
990 }
991
992 int ctdb_sys_read_tcp_packet(int s,
993 void *private_data,
994 ctdb_sock_addr *src,
995 ctdb_sock_addr *dst,
996 uint32_t *ack_seq,
997 uint32_t *seq,
998 int *rst,
999 uint16_t *window)
1000 {
1001 int ret;
1002 struct ether_header *eth;
1003 struct pcap_pkthdr pkthdr;
1004 const u_char *buffer;
1005 pcap_t *pt = (pcap_t *)private_data;
1006
1007 buffer=pcap_next(pt, &pkthdr);
1008 if (buffer==NULL) {
1009 return ENOMSG;
1010 }
1011
1012 ZERO_STRUCTP(src);
1013 ZERO_STRUCTP(dst);
1014
1015 /* Ethernet */
1016 eth = (struct ether_header *)buffer;
1017
1018 /* we want either IPv4 or IPv6 */
1019 if (eth->ether_type == htons(ETHERTYPE_IP)) {
1020 ret = tcp4_extract(buffer + sizeof(struct ether_header),
1021 (size_t)(pkthdr.caplen -
1022 sizeof(struct ether_header)),
1023 &src->ip,
1024 &dst->ip,
1025 ack_seq,
1026 seq,
1027 rst,
1028 window);
1029 return ret;
1030
1031 } else if (eth->ether_type == htons(ETHERTYPE_IP6)) {
1032 ret = tcp6_extract(buffer + sizeof(struct ether_header),
1033 (size_t)(pkthdr.caplen -
1034 sizeof(struct ether_header)),
1035 &src->ip6,
1036 &dst->ip6,
1037 ack_seq,
1038 seq,
1039 rst,
1040 window);
1041 return ret;
1042 }
1043
1044 return ENOMSG;
1045 }
1046
1047 #endif /* HAVE_AF_PACKET */
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