1 /* 6bed4/peer.c -- Peer-to-Peer IPv6-anywhere with 6bed4 -- peer.c
3 * This is an implementation of neighbour and router discovery over a
4 * tunnel that packs IPv6 inside UDP/IPv4. This tunnel mechanism is
5 * so efficient that the server administrators need not mind if it is
8 * From: Rick van Rein <rick@openfortress.nl>
25 #define LOG_PERROR LOG_CONS /* LOG_PERROR is non-POSIX, LOG_CONS is */
28 #include <sys/types.h>
29 #include <sys/socket.h>
31 #include <sys/select.h>
32 #include <sys/ioctl.h>
36 #include <netinet/in.h>
37 #include <netinet/ip.h>
38 #include <netinet/ip6.h>
39 #include <netinet/udp.h>
40 #include <netinet/icmp6.h>
41 #include <arpa/inet.h>
43 #include <asm/types.h>
44 //#include <linux/if.h>
45 #include <linux/if_tun.h>
46 #include <linux/if_ether.h>
47 #include <linux/netlink.h>
48 #include <linux/rtnetlink.h>
50 /* The following will initially fail, due to an IANA obligation to avoid
51 * default builds with non-standard options.
57 #define PREFIX_SIZE 114
66 * The HAVE_SETUP_TUNNEL variable is used to determine whether absense of
67 * the -d option leads to an error, or to an attempt to setup the tunnel.
68 * The setup_tunnel() function used for that is defined per platform, such
69 * as for LINUX. Remember to maintain the manpage's optionality for -d.
71 #undef HAVE_SETUP_TUNNEL
74 /* Global variables */
83 uint8_t v4qos = 0; /* Current QoS setting on UDP/IPv4 socket */
84 uint32_t v6tc = 0; /* Current QoS used by the IPv6 socket */
85 uint8_t v4ttl = 64; /* Default TTL setting on UDP/IPv4 socket */
86 int v4ttl_mcast = -1; /* Multicast TTL for LAN explorations */
88 char *v4server = NULL;
89 char *v6server = NULL;
90 char v6prefix [INET6_ADDRSTRLEN];
93 const uint8_t v6listen_linklocal [16] = { 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
94 uint8_t v6listen_linklocal_complete [16] = { 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
96 struct sockaddr_nl rtname;
97 struct sockaddr_nl rtkernel;
99 struct sockaddr_in v4name;
100 struct sockaddr_in v4peer;
101 struct sockaddr_in6 v6name;
103 struct sockaddr_in v4bind;
104 struct sockaddr_in v4allnodes;
106 struct in6_addr v6listen;
107 //TODO:NEEDNOT// struct in6_addr v6listen_complete;
108 struct in_addr v4listen;
119 struct ip6_hdr v6hdr;
120 uint8_t data [MTU - sizeof (struct ip6_hdr)];
123 struct ip6_hdr v6hdr;
124 struct icmp6_hdr v6icmphdr;
127 } __attribute__((packed)) v4data6;
130 #define v4ether (v4data6.eth)
132 #define v4tunpi6 (v4data6.tun)
134 #define v4data ((uint8_t *) &v4data6.udata)
135 #define v4hdr6 (&v4data6.udata.idata.v6hdr)
136 #define v4src6 (&v4data6.udata.idata.v6hdr.ip6_src)
137 #define v4dst6 (&v4data6.udata.idata.v6hdr.ip6_dst)
139 #define v4v6plen (v4data6.udata.ndata.v6hdr.ip6_plen)
140 #define v4v6nexthdr (v4data6.udata.ndata.v6hdr.ip6_nxt)
141 #define v4v6hoplimit (v4data6.udata.ndata.v6hdr.ip6_hops)
143 #define v4icmp6 (&v4data6.udata.ndata.v6icmphdr)
144 #define v4v6icmpdata (v4data6.udata.ndata.v6icmphdr.icmp6_data8)
145 #define v4v6icmptype (v4data6.udata.ndata.v6icmphdr.icmp6_type)
146 #define v4v6icmpcode (v4data6.udata.ndata.v6icmphdr.icmp6_code)
147 #define v4v6icmpcksum (v4data6.udata.ndata.v6icmphdr.icmp6_cksum)
148 #define v4v6ndtarget (&v4data6.udata.ndata.v6icmphdr.icmp6_data8 [4])
160 struct ip6_hdr v6hdr;
161 struct icmp6_hdr v6icmp;
162 } __attribute__((packed)) ndata;
164 } __attribute__((packed)) v6data6;
167 #define v6ether (v6data6.eth)
169 #define v6tuncmd (v6data6.tun)
171 #define v6data (v6data6.udata.data)
172 #define v6hdr6 (&v6data6.udata.ndata.v6hdr)
173 #define v6hops (v6data6.udata.ndata.v6hdr.ip6_hops)
174 #define v6type (v6data6.udata.ndata.v6hdr.ip6_nxt)
175 #define v6plen (v6data6.udata.ndata.v6hdr.ip6_plen)
176 #define v6src6 (&v6data6.udata.ndata.v6hdr.ip6_src)
177 #define v6dst6 (&v6data6.udata.ndata.v6hdr.ip6_dst)
178 #define v6icmp6type (v6data6.udata.ndata.v6icmp.icmp6_type)
179 #define v6icmp6code (v6data6.udata.ndata.v6icmp.icmp6_code)
180 #define v6icmp6data (v6data6.udata.ndata.v6icmp.icmp6_data8)
181 #define v6icmp6csum (v6data6.udata.ndata.v6icmp.icmp6_cksum)
182 #define v6ndtarget (&v6data6.udata.ndata.v6icmp.icmp6_data16[2])
185 #define HDR_SIZE (sizeof(struct ethhdr))
187 #define HDR_SIZE (sizeof(struct tun_pi))
190 /* Structure for tasks in neighbor discovery queues
193 struct ndqueue *next;
195 struct in6_addr source;
196 struct in6_addr target;
197 uint8_t source_lladdr [6];
198 uint8_t todo_lancast, todo_direct;
201 /* Round-robin queue for regular tasks, starting at previous value */
202 struct ndqueue *ndqueue = NULL;
203 struct ndqueue *freequeue = NULL;
204 uint32_t freequeue_items = 100;
206 /* The time for the next scheduled maintenance: routersol or keepalive.
207 * The milliseconds are always 0 for maintenance tasks.
209 time_t maintenance_time_sec;
210 time_t maintenance_time_cycle = 0;
211 time_t maintenance_time_cycle_max = 30;
212 bool got_lladdr = false;
213 time_t keepalive_period = 30;
214 time_t keepalive_ttl = -1;
216 /* The network packet structure of a 6bed4 Router Solicitation */
218 uint8_t ipv6_router_solicitation [] = {
220 0x60, 0x00, 0x00, 0x00,
221 16 >> 8, 16 & 0xff, IPPROTO_ICMPV6, 255,
222 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // unspecd src
223 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x02, // all-rtr tgt
224 // ICMPv6 header: router solicitation
225 ND_ROUTER_SOLICIT, 0, 0x7a, 0xae, // Checksum courtesy of WireShark :)
226 // ICMPv6 body: reserved
228 // ICMPv6 option: source link layer address 0x0001 (end-aligned)
229 0x01, 0x01, 0, 0, 0, 0, 0x00, 0x01,
232 uint8_t ipv6_defaultrouter_neighbor_advertisement [] = {
234 0x60, 0x00, 0x00, 0x00,
235 32 >> 8, 32 & 0xff, IPPROTO_ICMPV6, 255,
236 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // src is default router
237 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01,// dst is all-nodes multicast, portable?
238 // ICMPv6 header: neighbor solicitation
239 ND_NEIGHBOR_ADVERT, 0, 0x36, 0xf2, // Checksum courtesy of WireShark :)
240 // ICMPv6 Neighbor Advertisement: flags
243 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // the targeted neighbor
244 // ICMPv6 option: target link layer address
246 UDP_PORT_6BED4 & 0xff, UDP_PORT_6BED4 >> 8,
247 SERVER_6BED4_IPV4_INT0, SERVER_6BED4_IPV4_INT1, SERVER_6BED4_IPV4_INT2, SERVER_6BED4_IPV4_INT3
250 uint8_t router_linklocal_address [] = {
251 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x00,
254 //TODO// Complete with the if-id of the 6bed4 Router:
255 uint8_t router_linklocal_address_complete [] = {
256 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x00,
259 uint8_t client1_linklocal_address [] = {
260 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x01,
263 uint8_t allnodes_linklocal_address [] = {
264 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x01,
267 uint8_t allrouters_linklocal_address [] = {
268 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x02,
271 uint8_t solicitednodes_linklocal_prefix [13] = {
272 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01, 0xff
275 bool default_route = false;
277 bool foreground = false;
279 bool log_to_stderr = false;
281 bool multicast = true;
290 #ifndef INTERFACE_NAME_6BED4
291 #define INTERFACE_NAME_6BED4 "6bed4"
295 #define HAVE_SETUP_TUNNEL
296 static struct ifreq ifreq;
297 static bool have_tunnel = false;
298 /* Implement the setup_tunnel() command for Linux.
299 * Return true on success, false on failure.
301 bool setup_tunnel (void) {
303 v6sox = open ("/dev/net/tun", O_RDWR);
306 syslog (LOG_ERR, "%s: Failed to access tunnel driver on /dev/net/tun: %s\n", program, strerror (errno));
310 int flags = fcntl (v6sox, F_GETFL, 0);
312 syslog (LOG_CRIT, "Failed to retrieve flags for the tunnel file descriptor: %s\n", strerror (errno));
316 memset (&ifreq, 0, sizeof (ifreq));
317 strncpy (ifreq.ifr_name, INTERFACE_NAME_6BED4, IFNAMSIZ);
319 ifreq.ifr_flags = IFF_TAP | IFF_NO_PI;
321 ifreq.ifr_flags = IFF_TUN;
323 if (ok && (ioctl (v6sox, TUNSETIFF, (void *) &ifreq) == -1)) {
324 syslog (LOG_CRIT, "Failed to set interface name: %s\n", strerror (errno));
329 ifreq.ifr_name [IFNAMSIZ] = 0;
330 ifreq.ifr_ifindex = if_nametoindex (ifreq.ifr_name);
331 syslog (LOG_DEBUG, "Found Interface Index %d for name %s\n", ifreq.ifr_ifindex, ifreq.ifr_name);
332 ok = ok & (ifreq.ifr_ifindex != 0);
335 snprintf (cmd, 512, "/sbin/sysctl -q -w net.ipv6.conf.%s.forwarding=0", ifreq.ifr_name);
336 if (ok && system (cmd) != 0) {
339 snprintf (cmd, 512, "/sbin/sysctl -q -w net.ipv6.conf.%s.accept_dad=0", ifreq.ifr_name);
340 if (ok && system (cmd) != 0) {
344 close (v6sox); /* This removes the tunnel interface */
350 bool setup_tunnel_address (void) {
351 bool ok = have_tunnel;
354 snprintf (cmd, 512, "/sbin/sysctl -q -w net.ipv6.conf.%s.autoconf=0", ifreq.ifr_name);
355 if (ok && system (cmd) != 0) {
358 snprintf (cmd, 512, "/sbin/ip link set %s up mtu %d", ifreq.ifr_name, MTU);
359 if (ok && system (cmd) != 0) {
362 snprintf (cmd, 512, "/sbin/ip -6 addr add %s/114 dev %s", v6prefix, ifreq.ifr_name);
363 if (ok && system (cmd) != 0) {
367 snprintf (cmd, 512, "/sbin/ip -6 route add default via fe80:: dev %s metric 1042", ifreq.ifr_name);
368 if (ok && system (cmd) != 0) {
385 /* Produce an IPv6 address following the 6bed4 structures.
386 * - The top half is taken from v6listen
387 * - The bottom contains IPv4 address and port from v4name
388 * - The last 14 bits are filled with the lanip parameter
390 void addr_6bed4 (struct in6_addr *dst_ip6, uint16_t lanip) {
391 memcpy (&dst_ip6->s6_addr [0], &v6listen, 8);
392 dst_ip6->s6_addr32 [2] = v4name.sin_addr.s_addr;
393 dst_ip6->s6_addr16 [6] = v4name.sin_port;
394 dst_ip6->s6_addr [14] = ((dst_ip6->s6_addr [8] & 0x03) << 6)
395 | ((lanip >> 8) & 0x3f);
396 dst_ip6->s6_addr [15] = (lanip & 0xff);
397 dst_ip6->s6_addr [8] &= 0xfc;
400 /* Look for an entry in the 50ms-cycled Neighbor Discovery queue.
401 * Match the target address. Return the entry found, or NULL.
403 struct ndqueue *findqueue (struct in6_addr *target) {
404 struct ndqueue *ndq = ndqueue;
407 if (memcmp (target, &ndq->target, 16) == 0) {
411 } while (ndq != ndqueue);
416 /* Enter an item in the 50ms-cycled Neighbor Discovery queue.
417 * Retrieve its storage space from the free queue.
418 * TODO: Avoid double entries by looking up entries first -> "requeue?"
420 static int TODO_qlen;
421 void enqueue (struct in6_addr *target, struct in6_addr *v6src, uint8_t *source_lladdr) {
423 // Refuse to create double entries
424 if (findqueue (target)) {
428 // Allocate a free item to enqueue
429 struct ndqueue *new = freequeue;
431 // Temporarily overflown with ND -> drop the request
434 char tgt [INET6_ADDRSTRLEN]; inet_ntop (AF_INET6, target, tgt, sizeof (tgt));
435 syslog (LOG_DEBUG, "Queue++ => %d, looking for %s\n", ++TODO_qlen, tgt);
436 freequeue = freequeue->next;
438 // Setup the new entry with target details
439 memcpy (&new->target, target, sizeof (new->target));
440 memcpy (&new->source, v6src, sizeof (new->source));
441 memcpy (&new->source_lladdr, source_lladdr, sizeof (new->source_lladdr));
442 new->todo_lancast = (v4mcast == -1)? 0: 2;
443 new->todo_direct = 3;
445 // Time the new item to run instantly
448 // Enqueue the new item in front of the queue
450 new->next = ndqueue->next;
458 /* Remove an item from the 50ms-cycled Neighbor Discovery queue.
459 * Enter its storage space in the free queue.
461 void dequeue (struct ndqueue *togo) {
462 struct ndqueue *prev = ndqueue;
464 if (prev->next == togo) {
465 if (togo->next != togo) {
466 prev->next = togo->next;
467 if (ndqueue == togo) {
468 ndqueue = togo->next;
471 // Must be the only queued item
474 togo->next = freequeue;
476 syslog (LOG_DEBUG, "Queue-- => %d\n", --TODO_qlen);
480 } while (prev != ndqueue);
485 * Calculate the ICMPv6 checksum field
487 uint16_t icmp6_checksum (uint8_t *ipv6hdr, size_t payloadlen) {
488 uint16_t plenword = htons (payloadlen);
489 uint16_t nxthword = htons (IPPROTO_ICMPV6);
490 uint16_t *areaptr [] = { (uint16_t *) &ipv6hdr [8], (uint16_t *) &ipv6hdr [24], &plenword, &nxthword, (uint16_t *) &ipv6hdr [40], (uint16_t *) &ipv6hdr [40 + 4] };
491 uint8_t areawords [] = { 8, 8, 1, 1, 1, payloadlen/2 - 2 };
494 for (i=0; i < 6; i++) {
495 uint16_t *area = areaptr [i];
496 for (j=0; j<areawords [i]; j++) {
497 csum += ntohs (area [j]);
500 csum = (csum & 0xffff) + (csum >> 16);
501 csum = (csum & 0xffff) + (csum >> 16);
502 csum = htons (~csum);
508 * Send a Redirect reply. This is in response to a v4v6data message,
509 * and is directed straight at the origin's address but sent with a
512 * Note: Although the packet arrived in v4data6, the reply is built
513 * in v6data6 and sent from there as though it had come from
516 void redirect_reply (uint8_t *ngbc_llremote, metric_t ngbc_metric) {
517 void handle_6to4_plain_unicast (const ssize_t pktlen, const uint8_t *lladdr);
518 v6icmp6type = ND_REDIRECT;
523 v6icmp6data [3] = 0; // Reserved
524 memcpy (v6icmp6data + 4, &v6listen, 16);
525 // Target IPv6 address
526 switch (ngbc_metric) {
527 // Destination Address suggestion
530 // Redirect to the local-subnet IPv4 address
531 memcpy (v6icmp6data + 4 + 16, v6listen_linklocal, 8);
532 v6icmp6data [4 + 16 + 8 ] = v4peer.sin_port & 0x00ff;
533 v6icmp6data [4 + 16 + 9 ] = v4peer.sin_port >> 8;
534 memcpy (v6icmp6data + 4 + 16 + 12, &v4peer.sin_addr, 4);
535 v6icmp6data [4 + 16 + 10] = v4v6icmpdata [4 + 16 + 12];
536 v6icmp6data [4 + 16 + 11] = 0xff;
537 v6icmp6data [4 + 16 + 12] = 0xfe;
540 memcpy (v6icmp6data + 4 + 16, v6listen_linklocal_complete, 16);
544 return; /* no cause for Redirect, drop */
546 v6type = IPPROTO_ICMPV6;
547 v6plen = htons (8 + 16 + 16);
548 memcpy (v6src6, &v6listen, 16);
549 memcpy (v6dst6, v4src6, 16);
550 v6icmp6csum = icmp6_checksum ((uint8_t *) v4hdr6, 8 + 16 + 16);
551 handle_6to4_plain_unicast (HDR_SIZE + 40 + 8 + 16 + 16, ngbc_llremote);
555 /* Append the current prefix to an ICMPv6 message. Incoming optidx
556 * and return values signify original and new offset for ICMPv6 options.
557 * The endlife parameter must be set to obtain zero lifetimes, thus
558 * instructing the tunnel client to stop using an invalid prefix.
560 size_t icmp6_prefix (size_t optidx, uint8_t endlife) {
561 v6icmp6data [optidx++] = 3; // Type
562 v6icmp6data [optidx++] = 4; // Length
563 v6icmp6data [optidx++] = 114; // This is a /114 prefix
564 #ifndef COMPENSATE_FOR_AUTOCONF
565 v6icmp6data [optidx++] = 0xc0; // L=1, A=1, Reserved1=0
567 //TODO// Temporary fix: "ip -6 addr add .../64 dev 6bed4"
568 v6icmp6data [optidx++] = 0x80; // L=1, A=0, Reserved1=0
570 memset (v6icmp6data + optidx, endlife? 0x00: 0xff, 8);
572 // Valid Lifetime: Zero / Infinite
573 // Preferred Lifetime: Zero / Infinite
574 memset (v6icmp6data + optidx, 0, 4);
577 addr_6bed4 ((struct in6_addr *) (v6icmp6data + optidx), 0);
585 * Construct a Neighbor Advertisement message, providing the
586 * Public 6bed4 Service as the link-local address.
588 * This is done immediately when the IPv6 stack requests the link-local
589 * address for fe80:: through Router Solicition. In addition, it is the
590 * fallback response used when attempts to contact the remote peer at its
591 * direct IPv4 address and UDP port (its 6bed4 address) fails repeatedly.
593 * This routine is called with info==NULL to respond to an fe80::
594 * Neighbor Solicitation, otherwise with an info pointer containing
595 * a target IPv6 address to service.
597 void advertise_6bed4_public_service (struct ndqueue *info) {
601 memcpy (v6ether.h_dest, info->source_lladdr, 6);
603 memcpy (v6ether.h_dest, v6ether.h_source, 6);
605 memcpy (v6ether.h_source, SERVER_6BED4_PORT_IPV4_MACSTR, 6);
607 memcpy (v6data, ipv6_defaultrouter_neighbor_advertisement, 8);
609 memcpy (v6dst6, &info->source, 16);
611 memcpy (v6dst6, v6src6, 16);
614 memcpy (v6src6, &info->target, 16);
616 memcpy (v6src6, router_linklocal_address_complete, 16);
618 //TODO:OVERWROTE// memcpy (v6data + 8, ipv6_defaultrouter_neighbor_advertisement + 8, 16);
619 memcpy (v6data + 8 + 16 + 16, ipv6_defaultrouter_neighbor_advertisement + 8 + 16 + 16, sizeof (ipv6_defaultrouter_neighbor_advertisement) - 8 - 16 - 16);
621 // Overwrite target only for queued requests
622 memcpy (&v6icmp6data [4], &info->target, 16);
624 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 32);
625 int sent = write (v6sox, &v6data6, HDR_SIZE + sizeof (ipv6_defaultrouter_neighbor_advertisement));
627 syslog (LOG_DEBUG, "TODO: Neighbor Discovery failed to contact directly -- standard response provided\n");
629 syslog (LOG_DEBUG, "TODO: Neighbor Discovery for Public 6bed4 Service -- standard response provided\n");
635 * Validate the originator's IPv6 address. It should match the
636 * UDP/IPv4 coordinates of the receiving 6bed4 socket. Also,
637 * the /64 prefix (but not the /114 prefix!) must match v6listen.
639 bool validate_originator (struct in6_addr *ip6) {
642 // Communication from the configured router is welcomed
643 //TODO// Why should we trust the ip6 address at face value?
644 if ((v4name.sin_addr.s_addr == v4peer.sin_addr.s_addr)
645 && (v4name.sin_port == v4peer.sin_port)) {
649 // Require non-local top halves to match our v6listen_linklocal address
650 //TODO// When do we receive local top halves?
651 //TODO// We should really be more flexible and allow fallback addrs
652 if (memcmp (ip6, v6listen_linklocal, 8) != 0) {
653 if (memcmp (&v6listen, ip6->s6_addr, 8) != 0) {
658 // Require the sender port to appear in its IPv6 address
659 if (v4name.sin_port != ip6->s6_addr16 [6]) {
663 // Require the sender address to appear in its IPv6 address
664 addr = ntohl (ip6->s6_addr32 [2]) & 0xfcffffff;
665 addr |= ((uint32_t) (ip6->s6_addr [14] & 0xc0)) << (24-6);
666 if (addr != ntohl (v4name.sin_addr.s_addr)) {
670 // We passed with flying colours
676 * Translate a Link-Local Address to its metric. The metrics are
677 * numbered so that a higher number indicates a more costly path
678 * over which to connect. The values of the metric should not be
679 * published, but be treated as an opaque value with a complete
680 * ordering (that is: <, <=, >=, > relations) defined on it.
682 metric_t lladdr_metric (uint8_t *lladdr) {
683 uint32_t ipv4 = * (uint32_t *) (lladdr + 2);
685 // Metric 2: The 6bed4 Router address
686 if (ipv4 == v4peer.sin_addr.s_addr) {
690 // Metric 0: Private Addresses, as per RFC 1918
691 if ((ipv4 & 0xff000000) == 0x0a000000) {
692 return METRIC_LOW; /* 10.0.0./8 */
694 if ((ipv4 & 0xffff0000) == 0xc0a80000) {
695 return METRIC_LOW; /* 192.168.0.0/16 */
697 if ((ipv4 & 0xfff00000) == 0xac100000) {
698 return METRIC_LOW; /* 172.16.0.0/12 */
701 // Metric 1: Direct IPv4 contact is any other address
702 // Correctness should be checked elsewhere
703 return METRIC_MEDIUM;
708 * Retrieve the Link-Local Address, if any, for a given 6bed4 Peer.
709 * Return true on success, false on failure to find it. The lladdr
710 * parameter is only overwritten in case of success.
712 * Obviously, there is a point where it is more efficient to not
713 * lookup the cache for every request, but to cache it locally
714 * and limit the lookup frequency. This low-traffic optimal version
715 * is used here for initial simplicity, and because this is a peer
716 * daemon and a reference implementation. But who knows what people
717 * will submit as patches...
719 * Note: This code is specific to Linux, but note that BSD also has a
720 * NetLink concept, so it may port without needing to resort to
721 * shell commands running slowly in separate processes.
722 * Note: The interface for Linux is under-documented. Work may be
723 * needed to handle exception situations, such as going over
724 * invisible boundaries on the number of neighbours. Similarly,
725 * the use of alignment macros is rather unclear. This is not
726 * how I prefer to write code, but it's the best I can do now.
728 bool lookup_neighbor (uint8_t *ipv6, uint8_t *lladdr) {
734 memset (&msg, 0, sizeof (struct nlmsghdr) + sizeof (struct ndmsg));
735 msg.hd.nlmsg_len = NLMSG_LENGTH (sizeof (msg.nd));
736 msg.hd.nlmsg_type = RTM_GETNEIGH;
737 msg.hd.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT /* | NLM_F_MATCH */;
738 msg.hd.nlmsg_pid = rtname.nl_pid;
739 msg.nd.ndm_family = AF_INET6;
740 msg.nd.ndm_state = NUD_REACHABLE | NUD_DELAY | NUD_PROBE | NUD_PERMANENT | NUD_STALE; // Ignored by the kernel?
741 msg.nd.ndm_ifindex = ifreq.ifr_ifindex; // Ignored by the kernel?
742 // How to select an IPv6 address? Ignored by the kernel?
744 struct rtattr *ra1 = (struct rtattr *) (((char *) &msg) + sizeof (struct nlmsghdr) + sizeof (struct ndmsg));
745 ra1->rta_type = NDA_DST; // lookup IPv6 address
746 ra1->rta_len = RTA_LENGTH(16);
747 msg.hd.nlmsg_len = NLMSG_ALIGN (msg.hd.nlmsg_len) + RTA_LENGTH (16);
748 memcpy (RTA_DATA (ra1), ipv6, 16);
750 if (send (rtsox, &msg, msg.hd.nlmsg_len, MSG_DONTWAIT) == -1) {
755 { char buf [INET6_ADDRSTRLEN]; inet_ntop (AF_INET6, ipv6, buf, sizeof (buf)); syslog (LOG_DEBUG, "Looking up v6addr %s\n", buf); }
756 while (recvlen = recv (rtsox, ((char *) &msg) + pos, sizeof (msg) - pos, MSG_DONTWAIT), recvlen > 0) {
757 syslog (LOG_DEBUG, "Message of %zd bytes from neighbor cache, total is now %zd\n", recvlen, pos + recvlen);
761 while (resp = (struct mymsg *) (((char *) &msg) + pos),
762 (pos + sizeof (struct nlmsghdr) <= recvlen) &&
763 (pos + resp->hd.nlmsg_len <= recvlen)) {
764 bool ok = true, match = false;
765 uint8_t *result = NULL;
766 if (resp->hd.nlmsg_type == NLMSG_DONE) {
768 } else if (resp->hd.nlmsg_type != RTM_NEWNEIGH) {
769 syslog (LOG_ERR, "Kernel sent an unexpected nlmsg_type 0x%02x, ending neighbor interpretation\n", resp->hd.nlmsg_type);
771 } else if (resp->nd.ndm_ifindex != ifreq.ifr_ifindex) {
773 } else if (resp->nd.ndm_family != AF_INET6) {
774 syslog (LOG_ERR, "Kernel reported unknown neighbor family %d\n", resp->nd.ndm_family);
777 if (!(resp->nd.ndm_state & (NUD_REACHABLE | NUD_DELAY | NUD_PROBE | NUD_PERMANENT | NUD_STALE))) {
780 struct rtattr *ra = (struct rtattr *) ((char *) &resp + pos + sizeof (struct nlmsghdr) + sizeof (struct ndmsg) + 8);
782 while (ok && (rapos + ra->rta_len <= resp->hd.nlmsg_len)) {
783 switch (ra->rta_type) {
785 { char buf [INET6_ADDRSTRLEN]; inet_ntop (AF_INET6, RTA_DATA (ra), buf, sizeof (buf)); syslog (LOG_DEBUG, "Comparing against %s\n", buf); }
786 if (memcmp (ipv6, RTA_DATA (ra), 16) == 0) {
791 result = RTA_DATA (ra);
796 break; /* not of interest, skip */
798 rapos += ((ra->rta_len - 1) | 0x00000003) + 1;
799 ra = (struct rtattr *) (((char *) ra) + (((ra->rta_len - 1) | 0x0000003) + 1));
801 if (ok && match && result) {
802 memcpy (lladdr, result, 6);
803 return true; /* Yippy! Erfolg! */
805 pos += resp->hd.nlmsg_len;
807 // Copy remaining partial message to the beginning, continue from there
808 memcpy (&msg, ((char *) &msg) + pos, recvlen - pos);
816 * Major packet processing functions
820 /* Handle the IPv4 message pointed at by msg, checking if (TODO:HUH?) the IPv4:port
821 * data matches the lower half of the IPv6 sender address. Drop silently
822 * if this is not the case. TODO: or send ICMP?
824 void handle_4to6_plain (ssize_t v4datalen, struct sockaddr_in *sin) {
826 // Send the unwrapped IPv6 message out over v6sox
828 v4ether.h_proto = htons (ETH_P_IPV6);
829 memcpy (v4ether.h_dest, v6lladdr, 6);
830 v4ether.h_source [0] = ntohs (sin->sin_port) & 0xff;
831 v4ether.h_source [1] = ntohs (sin->sin_port) >> 8;
832 memcpy (v4ether.h_source + 2, &sin->sin_addr, 4);
834 syslog (LOG_INFO, "Writing IPv6, result = %zd\n",
835 write (v6sox, &v4data6, HDR_SIZE + v4datalen)
841 /* Handle the IPv4 message pointed at by msg as a neighbouring command.
843 * Type Code ICMPv6 meaning Handling
844 * ---- ---- ----------------------------- ----------------------------
845 * 133 0 Router Solicitation Ignore
846 * 134 0 Router Advertisement Setup Tunnel with Prefix
847 * 135 0 Neighbour Solicitation Send Neighbour Advertisement
848 * 136 0 Neighbour Advertisement Ignore
849 * 137 0 Redirect Ignore
851 void handle_4to6_nd (struct sockaddr_in *sin, ssize_t v4ngbcmdlen) {
852 uint16_t srclinklayer;
853 uint8_t *destprefix = NULL;
854 #ifdef TODO_DEPRECATED
855 uint8_t *destlladdr = NULL;
858 if (v4ngbcmdlen < sizeof (struct ip6_hdr) + sizeof (struct icmp6_hdr)) {
862 if (v4v6icmpcode != 0) {
865 if (icmp6_checksum (v4data, v4ngbcmdlen - sizeof (struct ip6_hdr)) != v4v6icmpcksum) {
869 // Approved. Perform neighbourly courtesy.
870 switch (v4v6icmptype) {
871 case ND_ROUTER_SOLICIT:
872 return; /* this is not a router, drop */
873 case ND_ROUTER_ADVERT:
875 // Validate Router Advertisement
876 if (ntohs (v4v6plen) < sizeof (struct icmp6_hdr) + 16) {
877 return; /* strange length, drop */
879 if (v4v6icmpdata [1] & 0x80 != 0x00) {
880 return; /* indecent proposal to use DHCPv6, drop */
882 if (memcmp (&v4src6->s6_addr, router_linklocal_address, 16) != 0) {
883 return; /* not from router, drop */
885 if (memcmp (&v4dst6->s6_addr, client1_linklocal_address, 8) != 0) {
886 if (memcmp (&v4dst6->s6_addr, allnodes_linklocal_address, 16) != 0) {
887 return; /* no address setup for me, drop */
890 if (v4dst6->s6_addr [8] & 0x01) {
891 syslog (LOG_WARNING, "TODO: Ignoring (by accepting) an odd public UDP port revealed in a Router Advertisement -- this could cause confusion with multicast traffic\n");
894 //TODO:+4_WRONG?// while (rdofs <= ntohs (v4v6plen) + 4) { ... }
895 while (rdofs + 4 < ntohs (v4v6plen)) {
896 if (v4v6icmpdata [rdofs + 1] == 0) {
897 return; /* zero length option */
899 #ifdef TODO_DEPRACATED
900 if ((v4v6icmpdata [rdofs + 0] == ND_OPT_DESTINATION_LINKADDR) && (v4v6icmpdata [rdofs + 1] == 1)) {
901 if (v4v6icmpdata [rdofs + 2] & 0x01) {
902 syslog (LOG_WARNING, "TODO: Ignoring an odd UDP port offered in a Router Advertisement over 6bed4\n");
904 syslog (LOG_INFO, "TODO: Set tunnel link-local address to %02x:%02x:%02x:%02x:%02x:%02x\n", v4v6icmpdata [rdofs + 2], v4v6icmpdata [rdofs + 3], v4v6icmpdata [rdofs + 4], v4v6icmpdata [rdofs + 5], v4v6icmpdata [rdofs + 6], v4v6icmpdata [rdofs + 7]);
905 destlladdr = &v4v6icmpdata [rdofs + 2];
906 /* continue with next option */
909 if (v4v6icmpdata [rdofs + 0] != ND_OPT_PREFIX_INFORMATION) {
910 /* skip to next option */
911 } else if (v4v6icmpdata [rdofs + 1] != 4) {
912 return; /* bad length field */
913 } else if (rdofs + (v4v6icmpdata [rdofs + 1] << 3) > ntohs (v4v6plen) + 4) {
914 return; /* out of packet length */
915 } else if (v4v6icmpdata [rdofs + 3] & 0xc0 != 0xc0) {
916 /* no on-link autoconfig prefix */
917 } else if (v4v6icmpdata [rdofs + 2] != PREFIX_SIZE) {
918 /* not a /114 prefix, so no 6bed4 offer */
921 destprefix = &v4v6icmpdata [rdofs + 16];
923 rdofs += (v4v6icmpdata [rdofs + 1] << 3);
926 memcpy (v6listen.s6_addr + 0, destprefix, 16);
927 v6listen.s6_addr [14] &= 0xc0;
928 v6listen.s6_addr [15] = 0x01; // choose client 1
929 memcpy (v6listen_linklocal_complete + 0, v6listen_linklocal, 8);
930 memcpy (v6listen_linklocal_complete + 8, v6listen.s6_addr + 8, 8);
931 memcpy (v6lladdr, destprefix + 8, 6);
932 //TODO// Is v6lladdr useful? Should it include lanip?
933 v6lladdr [0] &= 0xfc;
934 v6lladdr [0] |= (destprefix [14] >> 6);
939 syslog (LOG_INFO, "%s: Assigning address %s to tunnel\n", program, v6prefix);
940 setup_tunnel_address (); //TODO// parameters?
942 maintenance_time_cycle = maintenance_time_cycle_max;
943 maintenance_time_sec = time (NULL) + maintenance_time_cycle;
946 case ND_NEIGHBOR_SOLICIT:
948 // Validate Neigbour Solicitation (trivial)
950 // Replicate the message over the IPv6 Link (like plain IPv6)
951 if (v4ngbcmdlen < 24) {
952 return; /* too short, drop */
954 syslog (LOG_DEBUG, "%s: Replicating Neighbor Solicatation from 6bed4 to the IPv6 Link\n", program);
955 char buf [INET6_ADDRSTRLEN]; uint8_t ll [6]; if ((memcmp (v4src6, v6listen_linklocal, 8) != 0) && (memcmp (v4src6, &v6listen, 8) != 0)) { inet_ntop (AF_INET6, v4src6, buf, sizeof (buf)); syslog (LOG_DEBUG, "Source IPv6 address %s from wrong origin\n", buf); } else { uint8_t pfaddr [16]; memcpy (pfaddr, v6listen.s6_addr, 8); memcpy (pfaddr + 8, v4src6->s6_addr + 8, 8); inet_ntop (AF_INET6, pfaddr, buf, sizeof (buf)); if (lookup_neighbor (pfaddr, ll)) { syslog (LOG_DEBUG, "Source IPv6 %s has Link-Local Address %02x:%02x:%02x:%02x:%02x:%02x with metric %d\n", buf, ll [0], ll [1], ll [2], ll [3], ll [4], ll [5], lladdr_metric (ll)); } else { syslog (LOG_DEBUG, "Source IPv6 %s is unknown to me\n", buf); } }
956 uint8_t optofs = 4 + 16;
958 uint8_t *srcll = NULL; /* TODO -- use 6bed4 Network sender instead! */
959 while ((40 + 4 + optofs + 2 < v4ngbcmdlen) && (40 + 4 + optofs + 8 * v4v6icmpdata [optofs + 1] <= v4ngbcmdlen)) {
960 if (v4v6icmpdata [optofs] == 1) {
961 srcll = v4v6icmpdata + optofs + 2;
963 optofs += 8 * v4v6icmpdata [optofs + 1];
965 if (srcll) { syslog (LOG_DEBUG, "ND-contained Source Link-Layer Address %02x:%02x:%02x:%02x:%02x:%02x has metric %d\n", srcll [0], srcll [1], srcll [2], srcll [3], srcll [4], srcll [5], lladdr_metric (srcll)); }
968 // We should attach a Source Link-Layer Address, but
969 // we cannot automatically trust the one provided remotely.
970 // Also, we want to detect if routes differ, and handle it.
972 // 0. if no entry in the ngb.cache
973 // then use 6bed4 server in ND, initiate ngb.sol to src.ll
974 // impl: use 6bed4-server lladdr, set highest metric
975 // 1. if metric (ngb.cache) < metric (src.ll)
976 // then retain ngb.cache, send Redirect to source
977 // 2. if metric (ngb.cache) > metric (src.ll)
978 // then retain ngb.cache, initiate ngb.sol to src.ll
979 // 3. if metric (ngb.cache) == metric (src.ll)
980 // then retain ngb.cache
982 uint8_t src_lladdr [6];
983 src_lladdr [0] = ntohs (v4name.sin_port) & 0x00ff;
984 src_lladdr [1] = ntohs (v4name.sin_port) >> 8;
985 memcpy (src_lladdr + 2, &v4name.sin_addr, 4);
986 metric_t src_metric = lladdr_metric (src_lladdr);
987 v4v6icmpdata [4+16+0] = 1; /* Option: Source LLaddr */
988 v4v6icmpdata [4+16+1] = 1; /* Length: 1x 8 bytes */
989 uint8_t *ngbc_lladdr = v4v6icmpdata + 4+16+2;
990 uint8_t ngbc_ipv6 [16];
991 if (memcmp (v4src6, v6listen_linklocal, 8)) {
992 memcpy (ngbc_ipv6 + 0, &v6listen, 8);
993 memcpy (ngbc_ipv6 + 8, v4src6 + 8, 8);
995 memcpy (ngbc_ipv6, v4src6, 16);
997 bool ngbc_cached = lookup_neighbor (ngbc_ipv6, ngbc_lladdr);
998 metric_t ngbc_metric;
1000 ngbc_metric = lladdr_metric (ngbc_lladdr);
1002 ngbc_metric = METRIC_HIGH; /* trigger local ngbsol */
1003 memcpy (ngbc_lladdr, SERVER_6BED4_PORT_IPV4_MACSTR, 6);
1004 syslog (LOG_DEBUG, "Failed to find neighbor in cache, initialising it with the high metric\n");
1006 syslog (LOG_DEBUG, "Metric analysis: source lladdr %02x:%02x:%02x:%02x:%02x:%02x metric %d, neighbor cache lladdr %02x:%02x:%02x:%02x:%02x:%02x metric %d\n", src_lladdr [0], src_lladdr [1], src_lladdr [2], src_lladdr [3], src_lladdr [4], src_lladdr [5], src_metric, ngbc_lladdr [0], ngbc_lladdr [1], ngbc_lladdr [2], ngbc_lladdr [3], ngbc_lladdr [4], ngbc_lladdr [5], ngbc_metric);
1008 // Replicate the ngb.sol with the selected ngbc-lladdr
1009 v4v6icmpcksum = icmp6_checksum ((uint8_t *) v4hdr6, 8 + 16 + 8);
1010 handle_4to6_plain (40 + 24 + 8, &v4name);
1012 // If needed, initiate Neigbor Solicitation to the source
1013 // Note: Also when !ngbc_cached as the router is then cached
1014 if (ngbc_metric > src_metric) {
1015 syslog (LOG_DEBUG, "Trying to find the more direct route that the remote peer seems to be using\n");
1016 enqueue ((struct in6_addr *) v4src6, &v6listen, v6lladdr);
1019 // If needed, ask the source to redo Neighbor Solicitation
1020 if (ngbc_metric < src_metric) {
1021 syslog (LOG_DEBUG, "Redirecting the remote peer to the more efficient route that I am using\n");
1022 redirect_reply (ngbc_lladdr, ngbc_metric);
1025 case ND_NEIGHBOR_ADVERT:
1027 // Process Neighbor Advertisement coming in over 6bed4
1028 // First, make sure it is against an item in the ndqueue
1029 ndq = findqueue ((struct in6_addr *) v4v6ndtarget);
1031 // Ignore advertisement -- it may be an attack
1034 // Remove the matching item from the ndqueue
1036 // Replicate the Neigbor Advertisement over the IPv6 Link (like plain IPv6)
1037 v4v6icmpdata [0] |= 0xe0; /* Router, Solicited, Override */
1038 v4v6icmpdata [20] = 2; /* Target Link-Layer Address */
1039 v4v6icmpdata [21] = 1; /* Length: 1x 8 bytes */
1040 v4v6icmpdata [22] = ntohs (v4name.sin_port) & 0xff;
1041 v4v6icmpdata [23] = ntohs (v4name.sin_port) >> 8;
1042 memcpy (v4v6icmpdata + 24, &v4name.sin_addr, 4);
1043 v4v6plen = htons (24 + 8);
1044 v4v6icmpcksum = icmp6_checksum ((uint8_t *) v4hdr6, 24 + 8);
1045 handle_4to6_plain (sizeof (struct ip6_hdr) + 24 + 8, &v4name);
1049 // Redirect indicates that a more efficient bypass exists than
1050 // the currently used route. The remote peer has established
1051 // this and wants to share that information to retain a
1052 // symmetric communication, which is helpful in keeping holes
1053 // in NAT and firewalls open.
1055 //TODO// BE EXTREMELY SELECTIVE BEFORE ACCEPTING REDIRECT!!!
1056 //TODO:NOTYET// enqueue ((struct in6_addr *) v4v6ndtarget, &v6listen, v6lladdr);
1062 /* Receive a tunnel package, and route it to either the handler for the
1063 * tunnel protocol, or to the handler that checks and then unpacks the
1066 void handle_4to6 (int v4in) {
1069 socklen_t adrlen = sizeof (v4name);
1071 // Receive IPv4 package, which may be tunneled or a tunnel request
1072 buflen = recvfrom (v4in,
1075 (struct sockaddr *) &v4name, &adrlen
1078 syslog (LOG_INFO, "%s: WARNING: Error receiving IPv4-side package: %s\n",
1079 program, strerror (errno));
1080 return; /* receiving error, drop */
1082 if (buflen <= sizeof (struct ip6_hdr)) {
1083 return; /* received too little data, drop */
1085 if ((v4data [0] & 0xf0) != 0x60) {
1086 return; /* not an IPv6 packet, drop */
1088 if (!validate_originator (v4src6)) {
1089 return; /* source appears fake, drop */
1092 * Distinguish types of traffic:
1093 * Non-plain, Plain Unicast, Plain Multicast
1095 if ((v4v6nexthdr == IPPROTO_ICMPV6) &&
1096 (v4v6icmptype >= 133) && (v4v6icmptype <= 137)) {
1098 // Not Plain: Router Adv/Sol, Neighbor Adv/Sol, Redirect
1099 if (v4v6hoplimit != 255) {
1102 handle_4to6_nd (&v4name, buflen);
1105 // Plain Unicast or Plain Multicast (both may enter)
1106 if (v4v6hoplimit-- <= 1) {
1109 handle_4to6_plain (buflen, &v4name);
1115 * Relay an IPv6 package to 6bed4, using the link-local address as it
1116 * is found in the Ethernet header. Trust the local IPv6 stack to have
1117 * properly obtained this destination address through Neighbor Discovery
1120 void handle_6to4_plain_unicast (const ssize_t pktlen, const uint8_t *lladdr) {
1121 struct sockaddr_in v4dest;
1122 memset (&v4dest, 0, sizeof (v4dest));
1123 v4dest.sin_family = AF_INET;
1124 v4dest.sin_port = htons (lladdr [0] | (lladdr [1] << 8));
1125 memcpy (&v4dest.sin_addr, lladdr + 2, 4);
1126 if (v6tc != (v6hdr6->ip6_vfc & htonl (0x0ff00000))) {
1127 v6tc = v6hdr6->ip6_vfc & htonl (0x0ff00000);
1128 v4qos = (ntohl (v6hdr6->ip6_vfc) & 0x0ff00000) >> 24;
1129 if (setsockopt (v4sox, IPPROTO_IP, IP_TOS, &v4qos, sizeof (v4qos)) == -1) {
1130 syslog (LOG_ERR, "Failed to switch IPv4 socket to QoS setting 0x%02x\n", v4qos);
1133 syslog (LOG_DEBUG, "%s: Sending IPv6-UDP-IPv4 to %d.%d.%d.%d:%d, result = %zd\n", program,
1134 ((uint8_t *) &v4dest.sin_addr.s_addr) [0],
1135 ((uint8_t *) &v4dest.sin_addr.s_addr) [1],
1136 ((uint8_t *) &v4dest.sin_addr.s_addr) [2],
1137 ((uint8_t *) &v4dest.sin_addr.s_addr) [3],
1138 ntohs (v4dest.sin_port),
1143 (struct sockaddr *) &v4dest,
1144 sizeof (struct sockaddr_in))
1151 * Handle a request for Neighbor Discovery over the 6bed4 Link.
1153 void handle_6to4_nd (ssize_t pktlen) {
1156 // Validate ICMPv6 message -- trivial, trust local generation
1158 // Handle the message dependent on its type
1159 switch (v6icmp6type) {
1160 case ND_ROUTER_SOLICIT:
1161 v6icmp6type = ND_ROUTER_ADVERT;
1163 v6icmp6data [0] = 0; // Cur Hop Limit: unspec
1164 v6icmp6data [1] = 0x18; // M=0, O=0,
1167 //TODO: wire says 0x44 for router_adv.flags
1168 size_t writepos = 2;
1169 memset (v6icmp6data + writepos,
1170 default_route? 0xff: 0x00,
1171 2); // Router Lifetime
1173 memcpy (v6icmp6data + writepos,
1175 4); // Reachable Time: 32s
1177 memcpy (v6icmp6data + writepos,
1179 4); // Retrans Timer: .25s
1181 writepos = icmp6_prefix (writepos, 0);
1182 v6plen = htons (4 + writepos);
1183 memcpy (v6dst6, v6src6, 16);
1184 memcpy (v6src6, v6listen_linklocal_complete, 16);
1185 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 4 + writepos);
1187 v6ether.h_proto = htons (ETH_P_IPV6);
1188 memcpy (v6ether.h_dest, v6ether.h_source, 6);
1189 memcpy (v6ether.h_source, v6lladdr, 6);
1191 syslog (LOG_INFO, "Replying Router Advertisement to the IPv6 Link, result = %zd\n",
1192 write (v6sox, &v6data6, HDR_SIZE + sizeof (struct ip6_hdr) + 4 + writepos)
1196 case ND_ROUTER_ADVERT:
1197 return; /* the IPv6 Link is no router, drop */
1198 case ND_NEIGHBOR_SOLICIT:
1200 // Neighbor Solicitation is treated depending on its kind:
1201 // - the 6bed4 Router address is answered immediately
1202 // - discovery for the local IPv6 address is dropped
1203 // - discovery for fe80::/64 addresses is answered
1204 // - other peers start a process in the ndqueue
1205 if ((memcmp (v6ndtarget, router_linklocal_address, 16) == 0) ||
1206 (memcmp (v6ndtarget, router_linklocal_address_complete, 16) == 0)) {
1207 advertise_6bed4_public_service (NULL);
1208 } else if (memcmp (v6ndtarget, &v6listen, 16) == 0) {
1209 return; /* yes you are unique, drop */
1210 } else if (memcmp (v6ndtarget, v6listen_linklocal, 8) == 0) {
1212 // Construct response for fe80::/64
1213 v6icmp6type = ND_NEIGHBOR_ADVERT;
1214 v6icmp6data [0] = 0x60; /* Solicited, Override */
1215 v6icmp6data [20] = 2; /* Target Link-Layer Address */
1216 v6icmp6data [21] = 1; /* Length is 1x 8 bytes */
1217 v6icmp6data [22] = v6icmp6data [12] ^ 0x02;
1218 v6icmp6data [23] = v6icmp6data [13];
1219 v6icmp6data [24] = v6icmp6data [14];
1220 v6icmp6data [25] = v6icmp6data [17];
1221 v6icmp6data [26] = v6icmp6data [18];
1222 v6icmp6data [27] = v6icmp6data [19];
1223 v6plen = htons (4 + 28);
1224 memcpy (v6dst6, v6src6, 16);
1225 memcpy (v6src6, &v6listen, 16);
1227 memcpy (v6ether.h_dest, v6ether.h_source, 6);
1228 memcpy (v6ether.h_source, v6lladdr, 6);
1230 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 4 + 28);
1231 syslog (LOG_DEBUG, "Sending trivial reply to fe80::/64 type query\n");
1232 write (v6sox, &v6data6, HDR_SIZE + sizeof (struct ip6_hdr) + 4 + 28);
1237 enqueue ((struct in6_addr *) v6ndtarget, (struct in6_addr *) v6src6, v6ether.h_source);
1241 case ND_NEIGHBOR_ADVERT:
1242 lldest [0] = v6dst6->s6_addr [8] ^ 0x02;
1243 lldest [1] = v6dst6->s6_addr [9];
1244 lldest [2] = v6dst6->s6_addr [10];
1245 lldest [3] = v6dst6->s6_addr [13];
1246 lldest [4] = v6dst6->s6_addr [14];
1247 lldest [5] = v6dst6->s6_addr [15];
1248 handle_6to4_plain_unicast (pktlen, lldest);
1251 //TODO:NOT_IMPLEMENTED_YET:ND_REDIRECT_FROM_6BED4//
1253 // Redirect indicates that a more efficient bypass exists than
1254 // the currently used route. The remote peer has established
1255 // this and wants to share that information to retain a
1256 // symmetric communication, which is helpful in keeping holes
1257 // in NAT and firewalls open.
1264 * Receive an IPv6 package, check its address and pickup IPv4 address and
1265 * port, then package it as a tunnel message and forward it to IPv4:port.
1266 * Rely on the proper formatting of the incoming IPv6 packet, as it is
1267 * locally generated.
1269 void handle_6to4 (void) {
1270 #ifndef PEER_USE_TAP
1271 static uint8_t lladdr [] =
1274 UDP_PORT_6BED4 & 0xff,
1275 UDP_PORT_6BED4 >> 8,
1277 SERVER_6BED4_IPV4_INT0,
1278 SERVER_6BED4_IPV4_INT1,
1279 SERVER_6BED4_IPV4_INT2,
1280 SERVER_6BED4_IPV4_INT3
1284 // Receive the IPv6 package and ensure a consistent size
1285 size_t rawlen = read (v6sox, &v6data6, sizeof (v6data6));
1287 return; /* failure to read, drop */
1289 if (rawlen < HDR_SIZE + sizeof (struct ip6_hdr) + 1) {
1290 return; /* packet too small, drop */
1293 if (v6ether.h_proto != htons (ETH_P_IPV6)) {
1294 return; /* not IPv6, drop */
1296 //TODO// syslog (LOG_DEBUG, "Packet from IPv6 stack, target %02x:%02x:%02x:%02x:%02x:%02x\n", v6ether.h_dest [0], v6ether.h_dest [1], v6ether.h_dest [2], v6ether.h_dest [3], v6ether.h_dest [4], v6ether.h_dest [5]);
1298 // Ignore messages from the IPv6 stack to itself
1299 if (memcmp (v6ether.h_dest, v6ether.h_source, 6) == 0) {
1300 syslog (LOG_DEBUG, "TODO: Self-to-self messaging in IPv6 stack ignored\n");
1305 * Distinguish types of traffic:
1306 * Non-plain, Plain Unicast, Plain Multicast
1308 if ((v6type == IPPROTO_ICMPV6) &&
1309 (v6icmp6type >= 133) && (v6icmp6type <= 137)) {
1311 // Not Plain: Router Adv/Sol, Neighbor Adv/Sol, Redirect
1312 syslog (LOG_DEBUG, "Forwarding non-plain unicast from IPv6 to 6bed4\n");
1313 handle_6to4_nd (rawlen);
1314 } else if ((v6dst6->s6_addr [0] != 0xff) && !(v6dst6->s6_addr [8] & 0x01)) {
1317 if (v6hops-- <= 1) {
1320 syslog (LOG_DEBUG, "Forwarding plain unicast from IPv6 to 6bed4\n");
1322 handle_6to4_plain_unicast (rawlen, v6ether.h_dest);
1324 handle_6to4_plain_unicast (rawlen, lladdr);
1330 //TODO:IGNORE_MULTICAST//
1331 //TODO// syslog (LOG_DEBUG, "%s: Plain multicast from 6bed4 Link to 6bed4 Network is not supported\n", program);
1337 * Send a single Neighbor Solicitation message over 6bed4. This will
1338 * be sent to the given 6bed4 address, and is usually part of a series
1339 * of attempts to find a short-cut route to the 6bed4 peer.
1341 void solicit_6bed4_neighbor (const struct ndqueue *info, const uint8_t *addr6bed4) {
1342 memcpy (v6src6, &info->source, 16);
1343 memcpy (v6dst6, &info->target, 16);
1344 v6type = IPPROTO_ICMPV6;
1346 v6icmp6type = ND_NEIGHBOR_SOLICIT;
1351 v6icmp6data [3] = 0x00;
1352 memcpy (v6icmp6data + 4, &info->target, 16);
1353 v6icmp6data [20] = 1; // option type is Source Link-Layer Address
1354 v6icmp6data [21] = 1; // option length is 1x 8 bytes
1355 memcpy (v6icmp6data + 22, v6lladdr, 6);
1356 uint16_t pktlen = sizeof (struct ip6_hdr) + 4 + 28;
1357 //OLD// v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 28 + 8);
1358 v6plen = htons (4 + 28);
1359 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 4 + 28);
1360 handle_6to4_plain_unicast (sizeof (struct ip6_hdr) + 8 + 28 + 10, addr6bed4);
1361 //TODO// Why these +8 and +10 are needed, I don't know yet!
1366 * Find a neighbor's 6bed4 address. This is coordinated by the ndqueue,
1367 * which schedules such tasks and makes them repeat. Furthermore, a few
1368 * attempts may be scheduled on the local network before attempts
1369 * shift to the direct target IPv4/UDP addresses. Of course the local
1370 * network will only be scheduled if the public IPv4 address matches
1371 * the one for the local node.
1373 * This process is dequeued by reverse Neighbor Advertisements. If none
1374 * comes back in spite of the various Neighbor Solicitations sent, then
1375 * the final action is to send a Neighbor Advertisement to the host with
1376 * the Public 6bed4 Service as its target of last resort. In case of
1377 * this last resort, the process is not continued any further; the
1378 * return value indicates whether the queue entry should be kept for
1381 bool chase_neighbor_6bed4_address (struct ndqueue *info) {
1382 uint8_t addr6bed4 [6];
1383 static const uint8_t addr6bed4_lancast [8] = {
1384 UDP_PORT_6BED4 & 0xff, UDP_PORT_6BED4 >> 8,
1387 if (info->todo_lancast > 0) {
1388 // Attempt 1. Send to LAN multicast address (same public IP)
1389 info->todo_lancast--;
1390 solicit_6bed4_neighbor (info, addr6bed4_lancast);
1392 } else if (info->todo_direct > 0) {
1393 // Attempt 2. Send to target's direct IP address / UDP port
1394 info->todo_direct--;
1395 addr6bed4 [0] = info->target.s6_addr [8] ^ 0x02;
1396 addr6bed4 [1] = info->target.s6_addr [9];
1397 addr6bed4 [2] = info->target.s6_addr [10];
1398 addr6bed4 [3] = info->target.s6_addr [13];
1399 addr6bed4 [4] = info->target.s6_addr [14];
1400 addr6bed4 [5] = info->target.s6_addr [15];
1401 solicit_6bed4_neighbor (info, addr6bed4);
1404 // Attempt 3. Respond with Public 6bed4 Service
1405 syslog (LOG_INFO, "%s: Failed to find a bypass, passing back the 6bed4 Router\n", program);
1406 advertise_6bed4_public_service (info);
1413 * Perform Router Solicitation. This is the usual mechanism that is used
1414 * on ethernet links as well, except that the 6bed4 permits fixed interface
1415 * identifiers; for this client, the interface identifier will be 0x0001.
1416 * The router always has interface identifier 0x0000 but it will now be
1417 * addressed at the all-routers IPv6 address 0xff02::2 with the general
1418 * source IPv6 address ::
1420 void solicit_router (void) {
1421 v4name.sin_family = AF_INET;
1422 memcpy (&v4name.sin_addr.s_addr, &v4listen, 4);
1423 v4name.sin_port = htons (UDP_PORT_6BED4);
1426 // syslog (LOG_DEBUG, "%s: Sending RouterSolicitation-IPv6-UDP-IPv4 to %d.%d.%d.%d:%d, result = %d\n", program,
1427 // ((uint8_t *) &v4name.sin_addr.s_addr) [0],
1428 // ((uint8_t *) &v4name.sin_addr.s_addr) [1],
1429 // ((uint8_t *) &v4name.sin_addr.s_addr) [2],
1430 // ((uint8_t *) &v4name.sin_addr.s_addr) [3],
1431 // ntohs (v4name.sin_port),
1434 ipv6_router_solicitation,
1435 sizeof (ipv6_router_solicitation),
1437 (struct sockaddr *) &v4name, sizeof (v4name)));
1442 * Send a KeepAlive message. This is an UDP/IPv4 message with no contents.
1443 * The router will not respond, but that is okay; outgoing traffic is the
1444 * way to keep holes in NAT and firewalls open.
1446 void keepalive (void) {
1447 v4name.sin_family = AF_INET;
1448 memcpy (&v4name.sin_addr.s_addr, &v4listen, 4);
1449 v4name.sin_port = htons (UDP_PORT_6BED4);
1452 setsockopt (v4sox, IPPROTO_IP, IP_TTL, &keepalive_ttl, sizeof (keepalive_ttl));
1457 (struct sockaddr *) &v4name, sizeof (v4name));
1458 setsockopt (v4sox, IPPROTO_IP, IP_TTL, &v4ttl, sizeof (v4ttl));
1462 /* Regular maintenance is a routine that runs regularly to do one of two
1463 * generic tasks: either it sends Router Solicitation messages to the
1464 * Public 6bed4 Service, or it sends an empty UDP message somewhat in its
1465 * direction to keep NAT/firewall holes open.
1467 void regular_maintenance (void) {
1470 maintenance_time_cycle <<= 1;
1471 maintenance_time_cycle += 1;
1472 if (maintenance_time_cycle > maintenance_time_cycle_max) {
1473 maintenance_time_cycle = maintenance_time_cycle_max;
1475 syslog (LOG_INFO, "Sent Router Advertisement to Public 6bed4 Service, next attempt in %ld seconds\n", maintenance_time_cycle);
1477 syslog (LOG_INFO, "Sending a KeepAlive message (empty UDP) to the 6bed4 Router\n");
1479 maintenance_time_cycle = maintenance_time_cycle_max;
1481 maintenance_time_sec = time (NULL) + maintenance_time_cycle;
1485 /* Run the daemon core code, passing information between IPv4 and IPv6 and
1486 * responding to tunnel requests if so requested.
1488 void run_daemon (void) {
1491 maintenance_time_sec = 0; // trigger Router Solicitation
1493 FD_SET (v4sox, &io);
1494 FD_SET (v6sox, &io);
1495 int nfds = (v4sox < v6sox)? (v6sox + 1): (v4sox + 1);
1496 if (v4mcast != -1) {
1497 FD_SET (v4mcast, &io);
1498 if (v4mcast >= nfds) {
1503 struct timeval tout;
1505 gettimeofday (&now, NULL);
1506 if (maintenance_time_sec <= now.tv_sec) {
1507 regular_maintenance ();
1509 tout.tv_sec = maintenance_time_sec - now.tv_sec;
1512 ((ndqueue->next->tv.tv_sec == now.tv_sec)
1513 && (ndqueue->next->tv.tv_usec <= now.tv_usec))
1514 || (ndqueue->next->tv.tv_sec < now.tv_sec))) {
1516 // Run the entry's handler code
1517 syslog (LOG_DEBUG, "Queue at %ld.%03ld: Timed for %ld.%03ld", now.tv_sec, now.tv_usec / 1000, ndqueue->next->tv.tv_sec, ndqueue->next->tv.tv_usec / 1000);
1518 keep = chase_neighbor_6bed4_address (ndqueue->next);
1520 dequeue (ndqueue->next);
1524 // Make ndqueue point to the entry to run
1525 ndqueue = ndqueue->next;
1527 // Add 50ms to the running time
1528 if (now.tv_usec < 950000) {
1529 ndqueue->tv.tv_usec = now.tv_usec + 50000;
1530 ndqueue->tv.tv_sec = now.tv_sec + 0;
1532 ndqueue->tv.tv_usec = now.tv_usec - 950000;
1533 ndqueue->tv.tv_sec = now.tv_sec + 1;
1536 if (ndqueue && ((ndqueue->next->tv.tv_sec - now.tv_sec) < tout.tv_sec)) {
1537 tout.tv_sec = ndqueue->next->tv.tv_sec - now.tv_sec ;
1538 tout.tv_usec = ndqueue->next->tv.tv_usec - now.tv_usec;
1539 if (tout.tv_usec < 0) {
1540 tout.tv_usec += 1000000;
1544 if (select (nfds, &io, NULL, NULL, &tout) == -1) {
1545 syslog (LOG_ERR, "Select failed: %s\n", strerror (errno));
1547 if (FD_ISSET (v4sox, &io)) {
1548 syslog (LOG_DEBUG, "Got unicast input\n");
1549 handle_4to6 (v4sox);
1551 FD_SET (v4sox, &io);
1553 if (FD_ISSET (v6sox, &io)) {
1556 FD_SET (v6sox, &io);
1558 if (v4mcast != -1) {
1559 if (FD_ISSET (v4mcast, &io)) {
1560 syslog (LOG_DEBUG, "WOW: Got multicast input\n");
1561 handle_4to6 (v4mcast);
1563 FD_SET (v4mcast, &io);
1571 /* Option descriptive data structures */
1573 char *short_opt = "s:t:d:l:p:rk:feh";
1575 struct option long_opt [] = {
1576 { "v4server", 1, NULL, 's' },
1577 { "tundev", 1, NULL, 'd' },
1578 { "default-route", 0, NULL, 'r' },
1579 { "listen", 1, NULL, 'l' },
1580 { "port", 1, NULL, 'p' },
1581 { "ttl", 1, NULL, 't' },
1582 { "foreground", 0, NULL, 'f' },
1583 { "fork-not", 0, NULL, 'f' },
1584 { "keepalive", 1, NULL, 'k' },
1585 { "keepalive-period-ttl", 1, NULL, 'k' },
1586 { "error-console", 0, NULL, 'e' },
1587 { "help", 0, NULL, 'h' },
1588 { NULL, 0, NULL, 0 } /* Array termination */
1592 /* Parse commandline arguments (and start to process them).
1593 * Return 1 on success, 0 on failure.
1595 int process_args (int argc, char *argv []) {
1599 unsigned long tmpport;
1601 default_route = false;
1603 switch (getopt_long (argc, argv, short_opt, long_opt, NULL)) {
1606 if (optind != argc) {
1607 fprintf (stderr, "%s: Extra arguments not permitted: %s...\n", program, argv [optind]);
1614 fprintf (stderr, "%s: You can only specify a single server address\n", program);
1618 if (inet_pton (AF_INET, optarg, &v4peer.sin_addr) <= 0) {
1620 fprintf (stderr, "%s: Failed to parse IPv4 address %s\n", program, optarg);
1623 memcpy (&v4listen, &v4peer.sin_addr, 4);
1624 v4sox = socket (AF_INET, SOCK_DGRAM, 0);
1627 fprintf (stderr, "%s: Failed to allocate UDPv4 socket: %s\n", program, strerror (errno));
1634 fprintf (stderr, "%s: Multiple -d arguments are not permitted\n", program);
1637 v6sox = open (optarg, O_RDWR);
1640 fprintf (stderr, "%s: Failed to open tunnel device %s: %s\n", program, optarg, strerror (errno));
1645 if (default_route) {
1646 fprintf (stderr, "%s: You can only request default route setup once\n", program);
1649 default_route = true;
1652 if (inet_pton (AF_INET, optarg, &v4bind.sin_addr.s_addr) != 1) {
1653 fprintf (stderr, "%s: IPv4 address %s is not valid\n", program, optarg);
1658 tmpport = strtoul (optarg, &endarg, 10);
1659 if ((*endarg) || (tmpport > 65535)) {
1660 fprintf (stderr, "%s: UDP port number %s is not valid\n", program, optarg);
1663 if (tmpport & 0x0001) {
1664 fprintf (stderr, "%s: UDP port number %ld is odd, which is not permitted\n", program, tmpport);
1667 v4bind.sin_port = htons (tmpport);
1671 fprintf (stderr, "%s: You can only request foreground operation once\n", program);
1677 if (log_to_stderr) {
1678 fprintf (stderr, "%s: You can only specify logging to stderr once\n", program);
1681 log_to_stderr = true;
1684 if (v4ttl_mcast != -1) {
1685 fprintf (stderr, "%s: You can set the ttl for multicast once\n", program);
1689 long setting = strtol(optarg, &zero, 10);
1690 if (*zero || (setting < 0) || (setting > 255)) {
1691 fprintf (stderr, "%s: Multicast radius must be a number in the range 0 to 255, inclusive, not %s\n", program, optarg);
1694 v4ttl_mcast = setting;
1697 if (keepalive_ttl != -1) {
1698 fprintf (stderr, "%s: You can only set the keepalive period and TTL once\n", program);
1702 keepalive_period = strtol (optarg, &rest, 10);
1705 keepalive_ttl = strtol (rest, &rest, 10);
1706 if ((keepalive_ttl < 0) || (keepalive_ttl > 255)) {
1707 fprintf (stderr, "%s: The keepalive TTL must be in the range 0 to 255, inclusive\n", program);
1714 fprintf (stderr, "%s: The format for keepalive configuration is 'period,ttl' or just 'period', but not %s\n", program, optarg);
1721 /* continue into 'h' to produce usage information */
1731 #ifdef HAVE_SETUP_TUNNEL
1732 fprintf (stderr, "Usage: %s [-r] [-d /dev/tunX]\n %s -h\n", program, program);
1734 fprintf (stderr, "Usage: %s [-r] -d /dev/tunX\n %s -h\n", program, program);
1741 if (keepalive_ttl != -1) {
1742 maintenance_time_cycle_max = keepalive_period;
1746 #ifdef HAVE_SETUP_TUNNEL
1748 if (geteuid () != 0) {
1749 fprintf (stderr, "%s: You should be root, or use -d to specify an accessible tunnel device\n", program);
1752 return setup_tunnel ();
1755 #else /* ! HAVE_SETUP_TUNNEL */
1757 fprintf (stderr, "%s: You must specify a tunnel device with -d that is accessible to you\n", program);
1760 #endif /* HAVE_SETUP_TUNNEL */
1765 /* The main program parses commandline arguments and forks off the daemon
1767 int main (int argc, char *argv []) {
1770 program = strrchr (argv [0], '/');
1776 memset (&v4name, 0, sizeof (v4name));
1777 memset (&v4peer, 0, sizeof (v4peer));
1778 memset (&v6name, 0, sizeof (v6name));
1779 v4name.sin_family = AF_INET ;
1780 v4peer.sin_family = AF_INET ;
1781 v6name.sin6_family = AF_INET6;
1782 // Fixed public server data, IPv4 and UDP:
1783 v4server = SERVER_6BED4_IPV4_TXT;
1784 v4peer.sin_addr.s_addr = htonl (SERVER_6BED4_IPV4_INT32);
1785 v4name.sin_port = htons (UDP_PORT_6BED4);
1786 v4peer.sin_port = htons (UDP_PORT_6BED4);
1787 memcpy (&v4listen, &v4peer.sin_addr, 4);
1788 memset (&v4bind, 0, sizeof (v4bind));
1789 v4bind.sin_family = AF_INET;
1790 #ifndef PEER_USE_TAP
1792 v4tunpi6.proto = htons (ETH_P_IPV6);
1795 // Parse commandline arguments
1796 if (!process_args (argc, argv)) {
1800 // Construct the 6bed4 Router's complete link-layer address
1801 router_linklocal_address_complete [8] = (ntohs (v4peer.sin_port) & 0xff) ^ 0x02;
1802 router_linklocal_address_complete [9] = ntohs (v4peer.sin_port) >> 8;
1803 router_linklocal_address_complete [10] = ntohl (v4peer.sin_addr.s_addr) >> 24;
1804 router_linklocal_address_complete [11] = 0xff;
1805 router_linklocal_address_complete [12] = 0xfe;
1806 memcpy (router_linklocal_address_complete + 13, &((uint8_t *) &v4peer.sin_addr) [1], 3);
1808 // Open the syslog channel
1809 openlog (program, LOG_NDELAY | LOG_PID | ( log_to_stderr? LOG_PERROR: 0), LOG_DAEMON);
1811 // Create memory for the freequeue buffer
1812 freequeue = calloc (freequeue_items, sizeof (struct ndqueue));
1814 syslog (LOG_CRIT, "%s: Failed to allocate %d queue items\n", program, freequeue_items);
1818 for (i = 1; i < freequeue_items; i++) {
1819 freequeue [i].next = &freequeue [i-1];
1821 freequeue = &freequeue [freequeue_items - 1];
1823 // Create socket for normal outgoing (and return) 6bed4 traffic
1825 v4sox = socket (AF_INET, SOCK_DGRAM, 0);
1827 syslog (LOG_CRIT, "%s: Failed to open a local IPv4 socket -- does your system still support IPv4?\n", program);
1831 struct sockaddr_in tmpaddr;
1832 memset (&tmpaddr, 0, sizeof (tmpaddr));
1833 tmpaddr.sin_family = AF_INET;
1835 uint16_t portn = rand () & 0x3ffe;
1836 uint16_t port0 = portn + 16384;
1837 //TODO// Move port iteration + allocation to separate function
1838 while (portn < port0) {
1839 tmpaddr.sin_port = htons ((portn & 0x3ffe) + 49152);
1840 if (bind (v4sox, (struct sockaddr *) &tmpaddr, sizeof (tmpaddr)) == 0) {
1845 if (portn < port0) {
1846 syslog (LOG_DEBUG, "Bound to UDP port %d\n", ntohs (tmpaddr.sin_port));
1848 fprintf (stderr, "%s: All even dynamic ports rejected binding: %s\n", program, strerror (errno));
1852 // Setup fragmentation, QoS and TTL options
1855 #if defined(IP_DONTFRAG)
1856 if (setsockopt (v4sox, IPPROTO_IP, IP_DONTFRAG, no, sizeof (no)) == -1) {
1857 syslog (LOG_ERR, "Failed to permit fragmentation -- not all peers may be accessible with MTU 1280");
1859 #elif defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
1860 int pmtuflag = IP_PMTUDISC_DONT;
1861 if (setsockopt (v4sox, IP_MTU_DISCOVER, IP_MTU_DISCOVER, &pmtuflag, sizeof (pmtuflag)) == -1) {
1862 syslog (LOG_ERR, "Failed to permit fragmentation -- not all peers may be accessible with MTU 1280");
1865 #warning "Target system lacks support for controlling packet fragmentation"
1867 socklen_t soxlen = sizeof (v4qos);
1868 if (getsockopt (v4sox, IPPROTO_IP, IP_TOS, &v4qos, &soxlen) == -1) {
1869 syslog (LOG_ERR, "Quality of Service is not supported by the IPv4-side socket");
1872 v6tc = htonl (v4qos << 20);
1873 soxlen = sizeof (v4ttl);
1874 if (getsockopt (v4sox, IPPROTO_IP, IP_TTL, &v4ttl, &soxlen) == -1) {
1875 syslog (LOG_ERR, "Time To Live cannot be varied on the IPv4 socket");
1879 // Bind to the IPv4 all-nodes local multicast address
1880 memset (&v4allnodes, 0, sizeof (v4allnodes));
1881 v4allnodes.sin_family = AF_INET;
1882 v4allnodes.sin_port = htons (UDP_PORT_6BED4);
1883 v4allnodes.sin_addr.s_addr = htonl ( INADDR_ANY );
1885 v4mcast = socket (AF_INET, SOCK_DGRAM, 0);
1886 if (v4mcast != -1) {
1887 struct ip_mreq mreq;
1888 mreq.imr_multiaddr.s_addr = htonl ( (224L << 24) | 1L);
1889 mreq.imr_multiaddr.s_addr = htonl ( INADDR_ANY );
1890 if (bind (v4mcast, (struct sockaddr *) &v4allnodes, sizeof (v4allnodes)) != 0) {
1893 syslog (LOG_ERR, "No LAN bypass: Failed to bind to IPv4 all-nodes: %s\n", strerror (errno));
1894 } else if (setsockopt (v4mcast, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof (yes)) == -1) {
1897 syslog (LOG_ERR, "No LAN bypass: Failed to share multicast port: %s\n", strerror (errno));
1898 } else if (setsockopt (v4mcast, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof (mreq)) == -1) {
1901 syslog (LOG_ERR, "No LAN bypass: Failed to setup multicast: %s\n", strerror (errno));
1902 } else if ((v4ttl_mcast != -1) && (setsockopt (v4mcast, IPPROTO_IP, IP_MULTICAST_TTL, &v4ttl_mcast, sizeof (v4ttl_mcast)) == -1)) {
1905 syslog (LOG_ERR, "No LAN bypass: Failed to configure the multicast radius: %s\n", strerror (errno));
1908 if (bind (v4mcast, (struct sockaddr *) &v4allnodes, sizeof (v4allnodes)) != 0) {
1911 syslog (LOG_ERR, "%s: No LAN bypass: Failed to bind to IPv4 all-nodes\n", program);
1912 } else if (listen (v4mcast, 10) != 0) {
1915 syslog (LOG_ERR, "%s: No LAN bypass: Failed to listen to IPv4 all-nodes\n", program);
1920 syslog (LOG_INFO, "%s: No LAN bypass: Not desired\n", program);
1923 // Construct an rtnetlink socket for neighbor cache interaction
1924 rtsox = socket (PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
1926 syslog (LOG_CRIT, "Failed to gain access to the neighbor cache: %s\n", strerror (errno));
1929 memset (&rtname, 0, sizeof (rtname ));
1930 memset (&rtkernel, 0, sizeof (rtkernel));
1931 rtname.nl_family = rtkernel.nl_family = AF_NETLINK;
1932 rtname.nl_pid = getpid ();
1933 if (bind (rtsox, (struct sockaddr *) &rtname, sizeof (rtname)) == -1) {
1934 syslog (LOG_CRIT, "Failed to bind to the neighbor cache socket: %s\n", strerror (errno));
1937 if (connect (rtsox, (struct sockaddr *) &rtkernel, sizeof (rtkernel)) == -1) {
1938 syslog (LOG_CRIT, "Failed to connect to the neighbor cachr in the kernel; %s\n", strerror (errno));
1941 { uint8_t testll [6];
1942 uint8_t test_address [] = { 0xfe, 0x80, 0,0,0,0,0,0, 0xc2, 0x25, 0x06, 0xff, 0xfe, 0xb0, 0x7e, 0xa6 };
1943 if (lookup_neighbor (test_address, testll)) {
1944 syslog (LOG_INFO, "Successfully retrieved LL: %02x:%02x:%02x:%02x:%02x:%02x\n", testll [0], testll [1], testll [2], testll [3], testll [4], testll [5]);
1945 } else { syslog (LOG_INFO, "Failed to find LL\n"); } }
1947 // If port and/or listen arguments were provided, bind to them
1948 if ((v4bind.sin_addr.s_addr != INADDR_ANY) || (v4bind.sin_port != 0)) {
1949 if (bind (v4sox, (struct sockaddr *) &v4bind, sizeof (v4bind)) != 0) {
1950 syslog (LOG_CRIT, "%s: Failed to bind to local socket -- did you specify both address and port?\n", program);
1959 if (setsid () != -1) {
1960 syslog (LOG_CRIT, "%s: Failure to detach from parent session: %s\n", program, strerror (errno));
1965 syslog (LOG_CRIT, "%s: Failure to fork daemon process: %s\n", program, strerror (errno));
1969 if (! log_to_stderr) {
1980 // Report successful creation of the daemon