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>
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.
65 * The HAVE_SETUP_TUNNEL variable is used to determine whether absense of
66 * the -t option leads to an error, or to an attempt to setup the tunnel.
67 * The setup_tunnel() function used for that is defined per platform, such
68 * as for LINUX. Remember to maintain the manpage's optionality for -t.
70 #undef HAVE_SETUP_TUNNEL
73 /* Global variables */
82 uint8_t v4qos = 0; /* Current QoS setting on UDP/IPv4 socket */
83 uint32_t v6tc = 0; /* Current QoS used by the IPv6 socket */
84 uint8_t v4ttl = 64; /* Default TTL setting on UDP/IPv4 socket */
85 int v4ttl_mcast = -1; /* Multicast TTL for LAN explorations */
87 char *v4server = NULL;
88 char *v6server = NULL;
89 char v6prefix [INET6_ADDRSTRLEN];
92 const uint8_t v6listen_linklocal [16] = { 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
93 uint8_t v6listen_linklocal_complete [16] = { 0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
95 struct sockaddr_nl rtname;
96 struct sockaddr_nl rtkernel;
98 struct sockaddr_in v4name;
99 struct sockaddr_in v4peer;
100 struct sockaddr_in6 v6name;
102 struct sockaddr_in v4bind;
103 struct sockaddr_in v4allnodes;
105 struct in6_addr v6listen;
106 //TODO:NEEDNOT// struct in6_addr v6listen_complete;
107 struct in_addr v4listen;
114 struct ip6_hdr v6hdr;
115 uint8_t data [MTU - sizeof (struct ip6_hdr)];
118 struct ip6_hdr v6hdr;
119 struct icmp6_hdr v6icmphdr;
122 } __attribute__((packed)) v4data6;
124 #define v4ether (v4data6.eth)
125 #define v4data ((uint8_t *) &v4data6.udata)
126 #define v4hdr6 (&v4data6.udata.idata.v6hdr)
127 #define v4src6 (&v4data6.udata.idata.v6hdr.ip6_src)
128 #define v4dst6 (&v4data6.udata.idata.v6hdr.ip6_dst)
130 #define v4v6plen (v4data6.udata.ndata.v6hdr.ip6_plen)
131 #define v4v6nexthdr (v4data6.udata.ndata.v6hdr.ip6_nxt)
132 #define v4v6hoplimit (v4data6.udata.ndata.v6hdr.ip6_hops)
134 #define v4icmp6 (&v4data6.udata.ndata.v6icmphdr)
135 #define v4v6icmpdata (v4data6.udata.ndata.v6icmphdr.icmp6_data8)
136 #define v4v6icmptype (v4data6.udata.ndata.v6icmphdr.icmp6_type)
137 #define v4v6icmpcode (v4data6.udata.ndata.v6icmphdr.icmp6_code)
138 #define v4v6icmpcksum (v4data6.udata.ndata.v6icmphdr.icmp6_cksum)
139 #define v4v6ndtarget (&v4data6.udata.ndata.v6icmphdr.icmp6_data8 [4])
147 struct ip6_hdr v6hdr;
148 struct icmp6_hdr v6icmp;
149 } __attribute__((packed)) ndata;
151 } __attribute__((packed)) v6data6;
153 #define v6ether (v6data6.eth)
154 #define v6data (v6data6.udata.data)
155 #define v6hdr6 (&v6data6.udata.ndata.v6hdr)
156 #define v6hops (v6data6.udata.ndata.v6hdr.ip6_hops)
157 #define v6type (v6data6.udata.ndata.v6hdr.ip6_nxt)
158 #define v6plen (v6data6.udata.ndata.v6hdr.ip6_plen)
159 #define v6src6 (&v6data6.udata.ndata.v6hdr.ip6_src)
160 #define v6dst6 (&v6data6.udata.ndata.v6hdr.ip6_dst)
161 #define v6icmp6type (v6data6.udata.ndata.v6icmp.icmp6_type)
162 #define v6icmp6code (v6data6.udata.ndata.v6icmp.icmp6_code)
163 #define v6icmp6data (v6data6.udata.ndata.v6icmp.icmp6_data8)
164 #define v6icmp6csum (v6data6.udata.ndata.v6icmp.icmp6_cksum)
165 #define v6ndtarget (&v6data6.udata.ndata.v6icmp.icmp6_data16[2])
168 /* Structure for tasks in neighbor discovery queues
171 struct ndqueue *next;
173 struct in6_addr source;
174 struct in6_addr target;
175 uint8_t source_lladdr [6];
176 uint8_t todo_lancast, todo_direct;
179 /* Round-robin queue for regular tasks, starting at previous value */
180 struct ndqueue *ndqueue = NULL;
181 struct ndqueue *freequeue = NULL;
182 uint32_t freequeue_items = 100;
184 /* The time for the next scheduled maintenance: routersol or keepalive.
185 * The milliseconds are always 0 for maintenance tasks.
187 time_t maintenance_time_sec;
188 time_t maintenance_time_cycle = 0;
189 time_t maintenance_time_cycle_max = 30;
190 bool got_lladdr = false;
191 time_t keepalive_period = 30;
192 time_t keepalive_ttl = -1;
194 /* The network packet structure of a 6bed4 Router Solicitation */
196 uint8_t ipv6_router_solicitation [] = {
198 0x60, 0x00, 0x00, 0x00,
199 16 >> 8, 16 & 0xff, IPPROTO_ICMPV6, 255,
200 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // unspecd src
201 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x02, // all-rtr tgt
202 // ICMPv6 header: router solicitation
203 ND_ROUTER_SOLICIT, 0, 0x7a, 0xae, // Checksum courtesy of WireShark :)
204 // ICMPv6 body: reserved
206 // ICMPv6 option: source link layer address 0x0001 (end-aligned)
207 0x01, 0x01, 0, 0, 0, 0, 0x00, 0x01,
210 uint8_t ipv6_defaultrouter_neighbor_advertisement [] = {
212 0x60, 0x00, 0x00, 0x00,
213 32 >> 8, 32 & 0xff, IPPROTO_ICMPV6, 255,
214 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // src is default router
215 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01,// dst is all-nodes multicast, portable?
216 // ICMPv6 header: neighbor solicitation
217 ND_NEIGHBOR_ADVERT, 0, 0x36, 0xf2, // Checksum courtesy of WireShark :)
218 // ICMPv6 Neighbor Advertisement: flags
221 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // the targeted neighbor
222 // ICMPv6 option: target link layer address
224 UDP_PORT_6BED4 & 0xff, UDP_PORT_6BED4 >> 8,
225 SERVER_6BED4_IPV4_INT0, SERVER_6BED4_IPV4_INT1, SERVER_6BED4_IPV4_INT2, SERVER_6BED4_IPV4_INT3
228 uint8_t router_linklocal_address [] = {
229 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x00,
232 //TODO// Complete with the if-id of the 6bed4 Router:
233 uint8_t router_linklocal_address_complete [] = {
234 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x00,
237 uint8_t democlient_linklocal_address [] = {
238 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x01,
241 uint8_t allnodes_linklocal_address [] = {
242 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x01,
245 uint8_t allrouters_linklocal_address [] = {
246 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x00, 0x02,
249 uint8_t solicitednodes_linklocal_prefix [13] = {
250 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01, 0xff
253 bool default_route = false;
255 bool foreground = false;
257 bool log_to_stderr = false;
259 bool multicast = true;
269 #define HAVE_SETUP_TUNNEL
270 static struct ifreq ifreq;
271 static bool have_tunnel = false;
272 /* Implement the setup_tunnel() command for Linux.
273 * Return true on success, false on failure.
275 bool setup_tunnel (void) {
277 v6sox = open ("/dev/net/tun", O_RDWR);
280 syslog (LOG_ERR, "%s: Failed to access tunnel driver on /dev/net/tun: %s\n", program, strerror (errno));
284 int flags = fcntl (v6sox, F_GETFL, 0);
286 syslog (LOG_CRIT, "Failed to retrieve flags for the tunnel file descriptor: %s\n", strerror (errno));
290 memset (&ifreq, 0, sizeof (ifreq));
291 strncpy (ifreq.ifr_name, "6bed4", IFNAMSIZ);
292 ifreq.ifr_flags = IFF_TAP | IFF_NO_PI;
293 if (ok && (ioctl (v6sox, TUNSETIFF, (void *) &ifreq) == -1)) {
294 syslog (LOG_CRIT, "Failed to set interface name: %s\n", strerror (errno));
299 ifreq.ifr_name [IFNAMSIZ] = 0;
300 ifreq.ifr_ifindex = if_nametoindex (ifreq.ifr_name);
301 syslog (LOG_DEBUG, "Found Interface Index %d for name %s\n", ifreq.ifr_ifindex, ifreq.ifr_name);
302 ok = ok & (ifreq.ifr_ifindex != 0);
305 snprintf (cmd, 512, "/sbin/sysctl -q -w net.ipv6.conf.%s.forwarding=0", ifreq.ifr_name);
306 if (ok && system (cmd) != 0) {
309 snprintf (cmd, 512, "/sbin/sysctl -q -w net.ipv6.conf.%s.accept_dad=0", ifreq.ifr_name);
310 if (ok && system (cmd) != 0) {
314 close (v6sox); /* This removes the tunnel interface */
319 bool setup_tunnel_address (void) {
320 bool ok = have_tunnel;
323 snprintf (cmd, 512, "/sbin/sysctl -q -w net.ipv6.conf.%s.autoconf=0", ifreq.ifr_name);
324 if (ok && system (cmd) != 0) {
327 snprintf (cmd, 512, "/sbin/ip link set %s address %02x:%02x:%02x:%02x:%02x:%02x", ifreq.ifr_name, v6lladdr [0], v6lladdr [1], v6lladdr [2], v6lladdr [3], v6lladdr [4], v6lladdr [5]);
328 if (ok && system (cmd) != 0) {
329 syslog (LOG_CRIT, "Bad news!\n");
332 snprintf (cmd, 512, "/sbin/ip link set %s up mtu %d", ifreq.ifr_name, MTU);
333 if (ok && system (cmd) != 0) {
336 snprintf (cmd, 512, "/sbin/ip -6 addr add %s/64 dev %s", v6prefix, ifreq.ifr_name);
337 if (ok && system (cmd) != 0) {
341 snprintf (cmd, 512, "/sbin/ip -6 route add default via fe80:: dev %s", ifreq.ifr_name);
342 if (ok && system (cmd) != 0) {
358 /* Look for an entry in the 50ms-cycled Neighbor Discovery queue.
359 * Match the target address. Return the entry found, or NULL.
361 struct ndqueue *findqueue (struct in6_addr *target) {
362 struct ndqueue *ndq = ndqueue;
365 if (memcmp (target, &ndq->target, 16) == 0) {
369 } while (ndq != ndqueue);
374 /* Enter an item in the 50ms-cycled Neighbor Discovery queue.
375 * Retrieve its storage space from the free queue.
376 * TODO: Avoid double entries by looking up entries first -> "requeue?"
378 static int TODO_qlen;
379 void enqueue (struct in6_addr *target, struct in6_addr *v6src, uint8_t *source_lladdr) {
381 // Refuse to create double entries
382 if (findqueue (target)) {
386 // Allocate a free item to enqueue
387 struct ndqueue *new = freequeue;
389 // Temporarily overflown with ND -> drop the request
392 char tgt [INET6_ADDRSTRLEN]; inet_ntop (AF_INET6, target, tgt, sizeof (tgt));
393 syslog (LOG_DEBUG, "Queue++ => %d, looking for %s\n", ++TODO_qlen, tgt);
394 freequeue = freequeue->next;
396 // Setup the new entry with target details
397 memcpy (&new->target, target, sizeof (new->target));
398 memcpy (&new->source, v6src, sizeof (new->source));
399 memcpy (&new->source_lladdr, source_lladdr, sizeof (new->source_lladdr));
400 new->todo_lancast = (v4mcast == -1)? 0: 2;
401 new->todo_direct = 3;
403 // Time the new item to run instantly
406 // Enqueue the new item in front of the queue
408 new->next = ndqueue->next;
416 /* Remove an item from the 50ms-cycled Neighbor Discovery queue.
417 * Enter its storage space in the free queue.
419 void dequeue (struct ndqueue *togo) {
420 struct ndqueue *prev = ndqueue;
422 if (prev->next == togo) {
423 if (togo->next != togo) {
424 prev->next = togo->next;
425 if (ndqueue == togo) {
426 ndqueue = togo->next;
429 // Must be the only queued item
432 togo->next = freequeue;
434 syslog (LOG_DEBUG, "Queue-- => %d\n", --TODO_qlen);
438 } while (prev != ndqueue);
443 * Calculate the ICMPv6 checksum field
445 uint16_t icmp6_checksum (uint8_t *ipv6hdr, size_t payloadlen) {
446 uint16_t plenword = htons (payloadlen);
447 uint16_t nxthword = htons (IPPROTO_ICMPV6);
448 uint16_t *areaptr [] = { (uint16_t *) &ipv6hdr [8], (uint16_t *) &ipv6hdr [24], &plenword, &nxthword, (uint16_t *) &ipv6hdr [40], (uint16_t *) &ipv6hdr [40 + 4] };
449 uint8_t areawords [] = { 8, 8, 1, 1, 1, payloadlen/2 - 2 };
452 for (i=0; i < 6; i++) {
453 uint16_t *area = areaptr [i];
454 for (j=0; j<areawords [i]; j++) {
455 csum += ntohs (area [j]);
458 csum = (csum & 0xffff) + (csum >> 16);
459 csum = (csum & 0xffff) + (csum >> 16);
460 csum = htons (~csum);
466 * Send a Redirect reply. This is in response to a v4v6data message,
467 * and is directed straight at the origin's address but sent with a
470 * Note: Although the packet arrived in v4data6, the reply is built
471 * in v6data6 and sent from there as though it had come from
474 void redirect_reply (uint8_t *ngbc_llremote, metric_t ngbc_metric) {
475 void handle_6to4_plain_unicast (const ssize_t pktlen, const uint8_t *lladdr);
476 v6icmp6type = ND_REDIRECT;
481 v6icmp6data [3] = 0; // Reserved
482 memcpy (v6icmp6data + 4, &v6listen, 16);
483 // Target IPv6 address
484 switch (ngbc_metric) {
485 // Destination Address suggestion
488 // Redirect to the local-subnet IPv4 address
489 memcpy (v6icmp6data + 4 + 16, v6listen_linklocal, 8);
490 v6icmp6data [4 + 16 + 8 ] = v4peer.sin_port & 0x00ff;
491 v6icmp6data [4 + 16 + 9 ] = v4peer.sin_port >> 8;
492 memcpy (v6icmp6data + 4 + 16 + 12, &v4peer.sin_addr, 4);
493 v6icmp6data [4 + 16 + 10] = v4v6icmpdata [4 + 16 + 12];
494 v6icmp6data [4 + 16 + 11] = 0xff;
495 v6icmp6data [4 + 16 + 12] = 0xfe;
498 memcpy (v6icmp6data + 4 + 16, v6listen_linklocal_complete, 16);
502 return; /* no cause for Redirect, drop */
504 v6type = IPPROTO_ICMPV6;
505 v6plen = htons (8 + 16 + 16);
506 memcpy (v6src6, &v6listen, 16);
507 memcpy (v6dst6, v4src6, 16);
508 v6icmp6csum = icmp6_checksum ((uint8_t *) v4hdr6, 8 + 16 + 16);
509 handle_6to4_plain_unicast (sizeof (struct ethhdr) + 40 + 8 + 16 + 16, ngbc_llremote);
513 /* Append the current prefix to an ICMPv6 message. Incoming optidx
514 * and return values signify original and new offset for ICMPv6 options.
515 * The endlife parameter must be set to obtain zero lifetimes, thus
516 * instructing the tunnel client to stop using an invalid prefix.
518 size_t icmp6_prefix (size_t optidx, uint8_t endlife) {
519 v6icmp6data [optidx++] = 3; // Type
520 v6icmp6data [optidx++] = 4; // Length
521 v6icmp6data [optidx++] = 64; // This is a /64 prefix
522 #ifndef COMPENSATE_FOR_AUTOCONF
523 v6icmp6data [optidx++] = 0xc0; // L=1, A=1, Reserved1=0
525 //TODO// Temporary fix: "ip -6 addr add .../64 dev 6bed4"
526 v6icmp6data [optidx++] = 0x80; // L=1, A=0, Reserved1=0
528 memset (v6icmp6data + optidx, endlife? 0x00: 0xff, 8);
530 // Valid Lifetime: Zero / Infinite
531 // Preferred Lifetime: Zero / Infinite
532 memset (v6icmp6data + optidx, 0, 4);
535 memcpy (v6icmp6data + optidx + 0, &v6listen, 8);
536 memset (v6icmp6data + optidx + 8, 0, 8);
544 * Construct a Neighbor Advertisement message, providing the
545 * Public 6bed4 Service as the link-local address.
547 * This is done immediately when the IPv6 stack requests the link-local
548 * address for fe80:: through Router Solicition. In addition, it is the
549 * fallback response used when attempts to contact the remote peer at its
550 * direct IPv4 address and UDP port (its 6bed4 address) fails repeatedly.
552 * This routine is called with info==NULL to respond to an fe80::
553 * Neighbor Solicitation, otherwise with an info pointer containing
554 * a target IPv6 address to service.
556 void advertise_6bed4_public_service (struct ndqueue *info) {
558 memcpy (v6ether.h_dest, info->source_lladdr, 6);
560 memcpy (v6ether.h_dest, v6ether.h_source, 6);
562 memcpy (v6ether.h_source, SERVER_6BED4_PORT_IPV4_MACSTR, 6);
563 memcpy (v6data, ipv6_defaultrouter_neighbor_advertisement, 8);
565 memcpy (v6dst6, &info->source, 16);
567 memcpy (v6dst6, v6src6, 16);
570 memcpy (v6src6, &info->target, 16);
572 memcpy (v6src6, router_linklocal_address_complete, 16);
574 //TODO:OVERWROTE// memcpy (v6data + 8, ipv6_defaultrouter_neighbor_advertisement + 8, 16);
575 memcpy (v6data + 8 + 16 + 16, ipv6_defaultrouter_neighbor_advertisement + 8 + 16 + 16, sizeof (ipv6_defaultrouter_neighbor_advertisement) - 8 - 16 - 16);
577 // Overwrite target only for queued requests
578 memcpy (&v6icmp6data [4], &info->target, 16);
580 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 32);
581 int sent = write (v6sox, &v6data6, sizeof (struct ethhdr) + sizeof (ipv6_defaultrouter_neighbor_advertisement));
583 syslog (LOG_DEBUG, "TODO: Neighbor Discovery failed to contact directly -- standard response provided\n");
585 syslog (LOG_DEBUG, "TODO: Neighbor Discovery for Public 6bed4 Service -- standard response provided\n");
591 * Test if the provided IPv6 address matches the prefix used for 6bed4.
593 static inline bool prefix_6bed4 (struct in6_addr *ip6) {
594 return memcmp (&v6listen, ip6->s6_addr, 8) == 0;
599 * Validate the originator's IPv6 address. It should match the
600 * UDP/IPv4 coordinates of the receiving 6bed4 socket. Also,
601 * the /64 prefix must match that of v6listen.
603 bool validate_originator (struct sockaddr_in *sin, struct in6_addr *ip6) {
604 if ((sin->sin_addr.s_addr == v4peer.sin_addr.s_addr) && (sin->sin_port == v4peer.sin_port)) {
607 uint16_t port = ntohs (sin->sin_port);
608 uint32_t addr = ntohl (sin->sin_addr.s_addr);
609 if (memcmp (ip6, v6listen_linklocal, 8) != 0)
610 if (!prefix_6bed4 (ip6)) {
613 if ((port & 0xff) != (ip6->s6_addr [8] ^ 0x02)) {
616 if ((port >> 8) != ip6->s6_addr [9]) {
619 if ((addr >> 24) != ip6->s6_addr [10]) {
622 if ((addr & 0x00ffffff) != (htonl (ip6->s6_addr32 [3]) & 0x00ffffff)) {
630 * Translate a Link-Local Address to its metric. The metrics are
631 * numbered so that a higher number indicates a more costly path
632 * over which to connect. The values of the metric should not be
633 * published, but be treated as an opaque value with a complete
634 * ordering (that is: <, <=, >=, > relations) defined on it.
636 metric_t lladdr_metric (uint8_t *lladdr) {
637 uint32_t ipv4 = * (uint32_t *) (lladdr + 2);
639 // Metric 2: The 6bed4 Router address
640 if (ipv4 == v4peer.sin_addr.s_addr) {
644 // Metric 0: Private Addresses, as per RFC 1918
645 if ((ipv4 & 0xff000000) == 0x0a000000) {
646 return METRIC_LOW; /* 10.0.0./8 */
648 if ((ipv4 & 0xffff0000) == 0xc0a80000) {
649 return METRIC_LOW; /* 192.168.0.0/16 */
651 if ((ipv4 & 0xfff00000) == 0xac100000) {
652 return METRIC_LOW; /* 172.16.0.0/12 */
655 // Metric 1: Direct IPv4 contact is any other address
656 // Correctness should be checked elsewhere
657 return METRIC_MEDIUM;
662 * Retrieve the Link-Local Address, if any, for a given 6bed4 Peer.
663 * Return true on success, false on failure to find it. The lladdr
664 * parameter is only overwritten in case of success.
666 * Obviously, there is a point where it is more efficient to not
667 * lookup the cache for every request, but to cache it locally
668 * and limit the lookup frequency. This low-traffic optimal version
669 * is used here for initial simplicity, and because this is a peer
670 * daemon and a reference implementation. But who knows what people
671 * will submit as patches...
673 * Note: This code is specific to Linux, but note that BSD also has a
674 * NetLink concept, so it may port without needing to resort to
675 * shell commands running slowly in separate processes.
676 * Note: The interface for Linux is under-documented. Work may be
677 * needed to handle exception situations, such as going over
678 * invisible boundaries on the number of neighbours. Similarly,
679 * the use of alignment macros is rather unclear. This is not
680 * how I prefer to write code, but it's the best I can do now.
682 bool lookup_neighbor (uint8_t *ipv6, uint8_t *lladdr) {
688 memset (&msg, 0, sizeof (struct nlmsghdr) + sizeof (struct ndmsg));
689 msg.hd.nlmsg_len = NLMSG_LENGTH (sizeof (msg.nd));
690 msg.hd.nlmsg_type = RTM_GETNEIGH;
691 msg.hd.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT /* | NLM_F_MATCH */;
692 msg.hd.nlmsg_pid = rtname.nl_pid;
693 msg.nd.ndm_family = AF_INET6;
694 msg.nd.ndm_state = NUD_REACHABLE | NUD_DELAY | NUD_PROBE | NUD_PERMANENT | NUD_STALE; // Ignored by the kernel?
695 msg.nd.ndm_ifindex = ifreq.ifr_ifindex; // Ignored by the kernel?
696 // How to select an IPv6 address? Ignored by the kernel?
698 struct rtattr *ra1 = (struct rtattr *) (((char *) &msg) + sizeof (struct nlmsghdr) + sizeof (struct ndmsg));
699 ra1->rta_type = NDA_DST; // lookup IPv6 address
700 ra1->rta_len = RTA_LENGTH(16);
701 msg.hd.nlmsg_len = NLMSG_ALIGN (msg.hd.nlmsg_len) + RTA_LENGTH (16);
702 memcpy (RTA_DATA (ra1), ipv6, 16);
704 if (send (rtsox, &msg, msg.hd.nlmsg_len, MSG_DONTWAIT) == -1) {
709 { char buf [INET6_ADDRSTRLEN]; inet_ntop (AF_INET6, ipv6, buf, sizeof (buf)); syslog (LOG_DEBUG, "Looking up v6addr %s\n", buf); }
710 while (recvlen = recv (rtsox, ((char *) &msg) + pos, sizeof (msg) - pos, MSG_DONTWAIT), recvlen > 0) {
711 syslog (LOG_DEBUG, "Message of %zd bytes from neighbor cache, total is now %zd\n", recvlen, pos + recvlen);
715 while (resp = (struct mymsg *) (((char *) &msg) + pos),
716 (pos + sizeof (struct nlmsghdr) <= recvlen) &&
717 (pos + resp->hd.nlmsg_len <= recvlen)) {
718 bool ok = true, match = false;
719 uint8_t *result = NULL;
720 if (resp->hd.nlmsg_type == NLMSG_DONE) {
722 } else if (resp->hd.nlmsg_type != RTM_NEWNEIGH) {
723 syslog (LOG_ERR, "Kernel sent an unexpected nlmsg_type 0x%02x, ending neighbor interpretation\n", resp->hd.nlmsg_type);
725 } else if (resp->nd.ndm_ifindex != ifreq.ifr_ifindex) {
727 } else if (resp->nd.ndm_family != AF_INET6) {
728 syslog (LOG_ERR, "Kernel reported unknown neighbor family %d\n", resp->nd.ndm_family);
731 if (!(resp->nd.ndm_state & (NUD_REACHABLE | NUD_DELAY | NUD_PROBE | NUD_PERMANENT | NUD_STALE))) {
734 struct rtattr *ra = (struct rtattr *) ((char *) &resp + pos + sizeof (struct nlmsghdr) + sizeof (struct ndmsg) + 8);
736 while (ok && (rapos + ra->rta_len <= resp->hd.nlmsg_len)) {
737 switch (ra->rta_type) {
739 { char buf [INET6_ADDRSTRLEN]; inet_ntop (AF_INET6, RTA_DATA (ra), buf, sizeof (buf)); syslog (LOG_DEBUG, "Comparing against %s\n", buf); }
740 if (memcmp (ipv6, RTA_DATA (ra), 16) == 0) {
745 result = RTA_DATA (ra);
750 break; /* not of interest, skip */
752 rapos += ((ra->rta_len - 1) | 0x00000003) + 1;
753 ra = (struct rtattr *) (((char *) ra) + (((ra->rta_len - 1) | 0x0000003) + 1));
755 if (ok && match && result) {
756 memcpy (lladdr, result, 6);
757 return true; /* Yippy! Erfolg! */
759 pos += resp->hd.nlmsg_len;
761 // Copy remaining partial message to the beginning, continue from there
762 memcpy (&msg, ((char *) &msg) + pos, recvlen - pos);
770 * Major packet processing functions
774 /* Handle the IPv4 message pointed at by msg, checking if (TODO:HUH?) the IPv4:port
775 * data matches the lower half of the IPv6 sender address. Drop silently
776 * if this is not the case. TODO: or send ICMP?
778 void handle_4to6_plain (ssize_t v4datalen, struct sockaddr_in *sin) {
780 // Send the unwrapped IPv6 message out over v6sox
781 v4ether.h_proto = htons (ETH_P_IPV6);
782 memcpy (v4ether.h_dest, v6lladdr, 6);
783 v4ether.h_source [0] = ntohs (sin->sin_port) & 0xff;
784 v4ether.h_source [1] = ntohs (sin->sin_port) >> 8;
785 memcpy (v4ether.h_source + 2, &sin->sin_addr, 4);
786 syslog (LOG_INFO, "Writing IPv6, result = %zd\n",
787 write (v6sox, &v4data6, sizeof (struct ethhdr) + v4datalen)
793 /* Handle the IPv4 message pointed at by msg as a neighbouring command.
795 * Type Code ICMPv6 meaning Handling
796 * ---- ---- ----------------------------- ----------------------------
797 * 133 0 Router Solicitation Ignore
798 * 134 0 Router Advertisement Setup Tunnel with Prefix
799 * 135 0 Neighbour Solicitation Send Neighbour Advertisement
800 * 136 0 Neighbour Advertisement Ignore
801 * 137 0 Redirect Ignore
803 void handle_4to6_nd (struct sockaddr_in *sin, ssize_t v4ngbcmdlen) {
804 uint16_t srclinklayer;
805 uint8_t *destprefix = NULL;
806 #ifdef TODO_DEPRECATED
807 uint8_t *destlladdr = NULL;
810 if (v4ngbcmdlen < sizeof (struct ip6_hdr) + sizeof (struct icmp6_hdr)) {
814 if (v4v6icmpcode != 0) {
817 if (icmp6_checksum (v4data, v4ngbcmdlen - sizeof (struct ip6_hdr)) != v4v6icmpcksum) {
821 // Approved. Perform neighbourly courtesy.
822 switch (v4v6icmptype) {
823 case ND_ROUTER_SOLICIT:
824 return; /* this is not a router, drop */
825 case ND_ROUTER_ADVERT:
827 // Validate Router Advertisement
828 if (ntohs (v4v6plen) < sizeof (struct icmp6_hdr) + 16) {
829 return; /* strange length, drop */
831 if (v4v6icmpdata [1] & 0x80 != 0x00) {
832 return; /* indecent proposal to use DHCPv6, drop */
834 if (memcmp (v4src6, router_linklocal_address, 16) != 0) {
835 return; /* not from router, drop */
837 if (memcmp (v4dst6, democlient_linklocal_address, 8) != 0) {
838 return; /* no address setup for me, drop */
840 if (v4dst6->s6_addr [8] & 0x01) {
841 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");
844 //TODO:+4_WRONG?// while (rdofs <= ntohs (v4v6plen) + 4) { ... }
845 while (rdofs + 4 < ntohs (v4v6plen)) {
846 if (v4v6icmpdata [rdofs + 1] == 0) {
847 return; /* zero length option */
849 #ifdef TODO_DEPRACATED
850 if ((v4v6icmpdata [rdofs + 0] == ND_OPT_DESTINATION_LINKADDR) && (v4v6icmpdata [rdofs + 1] == 1)) {
851 if (v4v6icmpdata [rdofs + 2] & 0x01) {
852 syslog (LOG_WARNING, "TODO: Ignoring an odd UDP port offered in a Router Advertisement over 6bed4\n");
854 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]);
855 destlladdr = &v4v6icmpdata [rdofs + 2];
856 /* continue with next option */
859 if (v4v6icmpdata [rdofs + 0] != ND_OPT_PREFIX_INFORMATION) {
860 /* skip to next option */
861 } else if (v4v6icmpdata [rdofs + 1] != 4) {
862 return; /* bad length field */
863 } else if (rdofs + (v4v6icmpdata [rdofs + 1] << 3) > ntohs (v4v6plen) + 4) {
864 return; /* out of packet length */
865 } else if (v4v6icmpdata [rdofs + 3] & 0xc0 != 0xc0) {
866 /* no on-link autoconfig prefix */
867 } else if (v4v6icmpdata [rdofs + 2] != 64) {
870 destprefix = &v4v6icmpdata [rdofs + 16];
872 rdofs += (v4v6icmpdata [rdofs + 1] << 3);
875 memcpy (v6listen.s6_addr + 0, destprefix, 8);
876 memcpy (v6listen.s6_addr + 8, v4dst6->s6_addr + 8, 8);
877 memcpy (v6listen_linklocal_complete, v4dst6, 16);
878 v6lladdr [0] = v6listen_linklocal_complete [8] ^ 0x02;
879 v6lladdr [1] = v6listen_linklocal_complete [9];
880 v6lladdr [2] = v6listen_linklocal_complete [10];
881 v6lladdr [3] = v6listen_linklocal_complete [13];
882 v6lladdr [4] = v6listen_linklocal_complete [14];
883 v6lladdr [5] = v6listen_linklocal_complete [15];
888 syslog (LOG_INFO, "%s: Assigning address %s to tunnel\n", program, v6prefix);
889 setup_tunnel_address (); //TODO// parameters?
891 maintenance_time_cycle = maintenance_time_cycle_max;
892 maintenance_time_sec = time (NULL) + maintenance_time_cycle;
895 case ND_NEIGHBOR_SOLICIT:
897 // Validate Neigbour Solicitation (trivial)
899 // Replicate the message over the IPv6 Link (like plain IPv6)
900 if (v4ngbcmdlen < 24) {
901 return; /* too short, drop */
903 syslog (LOG_DEBUG, "%s: Replicating Neighbor Solicatation from 6bed4 to the IPv6 Link\n", program);
904 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); } }
905 uint8_t optofs = 4 + 16;
907 uint8_t *srcll = NULL; /* TODO -- use 6bed4 Network sender instead! */
908 while ((40 + 4 + optofs + 2 < v4ngbcmdlen) && (40 + 4 + optofs + 8 * v4v6icmpdata [optofs + 1] <= v4ngbcmdlen)) {
909 if (v4v6icmpdata [optofs] == 1) {
910 srcll = v4v6icmpdata + optofs + 2;
912 optofs += 8 * v4v6icmpdata [optofs + 1];
914 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)); }
917 // We should attach a Source Link-Layer Address, but
918 // we cannot automatically trust the one provided remotely.
919 // Also, we want to detect if routes differ, and handle it.
921 // 0. if no entry in the ngb.cache
922 // then use 6bed4 server in ND, initiate ngb.sol to src.ll
923 // impl: use 6bed4-server lladdr, set highest metric
924 // 1. if metric (ngb.cache) < metric (src.ll)
925 // then retain ngb.cache, send Redirect to source
926 // 2. if metric (ngb.cache) > metric (src.ll)
927 // then retain ngb.cache, initiate ngb.sol to src.ll
928 // 3. if metric (ngb.cache) == metric (src.ll)
929 // then retain ngb.cache
931 uint8_t src_lladdr [6];
932 src_lladdr [0] = ntohs (v4name.sin_port) & 0x00ff;
933 src_lladdr [1] = ntohs (v4name.sin_port) >> 8;
934 memcpy (src_lladdr + 2, &v4name.sin_addr, 4);
935 metric_t src_metric = lladdr_metric (src_lladdr);
936 v4v6icmpdata [4+16+0] = 1; /* Option: Source LLaddr */
937 v4v6icmpdata [4+16+1] = 1; /* Length: 1x 8 bytes */
938 uint8_t *ngbc_lladdr = v4v6icmpdata + 4+16+2;
939 uint8_t ngbc_ipv6 [16];
940 if (memcmp (v4src6, v6listen_linklocal, 8)) {
941 memcpy (ngbc_ipv6 + 0, &v6listen, 8);
942 memcpy (ngbc_ipv6 + 8, v4src6 + 8, 8);
944 memcpy (ngbc_ipv6, v4src6, 16);
946 bool ngbc_cached = lookup_neighbor (ngbc_ipv6, ngbc_lladdr);
947 metric_t ngbc_metric;
949 ngbc_metric = lladdr_metric (ngbc_lladdr);
951 ngbc_metric = METRIC_HIGH; /* trigger local ngbsol */
952 memcpy (ngbc_lladdr, SERVER_6BED4_PORT_IPV4_MACSTR, 6);
953 syslog (LOG_DEBUG, "Failed to find neighbor in cache, initialising it with the high metric\n");
955 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);
957 // Replicate the ngb.sol with the selected ngbc-lladdr
958 v4v6icmpcksum = icmp6_checksum ((uint8_t *) v4hdr6, 8 + 16 + 8);
959 handle_4to6_plain (40 + 24 + 8, &v4name);
961 // If needed, initiate Neigbor Solicitation to the source
962 // Note: Also when !ngbc_cached as the router is then cached
963 if (ngbc_metric > src_metric) {
964 syslog (LOG_DEBUG, "Trying to find the more direct route that the remote peer seems to be using\n");
965 enqueue ((struct in6_addr *) v4src6, &v6listen, v6lladdr);
968 // If needed, ask the source to redo Neighbor Solicitation
969 if (ngbc_metric < src_metric) {
970 syslog (LOG_DEBUG, "Redirecting the remote peer to the more efficient route that I am using\n");
971 redirect_reply (ngbc_lladdr, ngbc_metric);
974 case ND_NEIGHBOR_ADVERT:
976 // Process Neighbor Advertisement coming in over 6bed4
977 // First, make sure it is against an item in the ndqueue
978 ndq = findqueue ((struct in6_addr *) v4v6ndtarget);
980 // Ignore advertisement -- it may be an attack
983 // Remove the matching item from the ndqueue
985 // Replicate the Neigbor Advertisement over the IPv6 Link (like plain IPv6)
986 v4v6icmpdata [0] |= 0xe0; /* Router, Solicited, Override */
987 v4v6icmpdata [20] = 2; /* Target Link-Layer Address */
988 v4v6icmpdata [21] = 1; /* Length: 1x 8 bytes */
989 v4v6icmpdata [22] = ntohs (v4name.sin_port) & 0xff;
990 v4v6icmpdata [23] = ntohs (v4name.sin_port) >> 8;
991 memcpy (v4v6icmpdata + 24, &v4name.sin_addr, 4);
992 v4v6plen = htons (24 + 8);
993 v4v6icmpcksum = icmp6_checksum ((uint8_t *) v4hdr6, 24 + 8);
994 handle_4to6_plain (sizeof (struct ip6_hdr) + 24 + 8, &v4name);
998 // Redirect indicates that a more efficient bypass exists than
999 // the currently used route. The remote peer has established
1000 // this and wants to share that information to retain a
1001 // symmetric communication, which is helpful in keeping holes
1002 // in NAT and firewalls open.
1004 //TODO// BE EXTREMELY SELECTIVE BEFORE ACCEPTING REDIRECT!!!
1005 //TODO:NOTYET// enqueue ((struct in6_addr *) v4v6ndtarget, &v6listen, v6lladdr);
1011 /* Receive a tunnel package, and route it to either the handler for the
1012 * tunnel protocol, or to the handler that checks and then unpacks the
1015 void handle_4to6 (int v4in) {
1018 socklen_t adrlen = sizeof (v4name);
1020 // Receive IPv4 package, which may be tunneled or a tunnel request
1021 buflen = recvfrom (v4in,
1024 (struct sockaddr *) &v4name, &adrlen
1027 syslog (LOG_INFO, "%s: WARNING: Error receiving IPv4-side package: %s\n",
1028 program, strerror (errno));
1029 return; /* receiving error, drop */
1031 if (buflen <= sizeof (struct ip6_hdr)) {
1032 return; /* received too little data, drop */
1034 if ((v4data [0] & 0xf0) != 0x60) {
1035 return; /* not an IPv6 packet, drop */
1037 if (!validate_originator (&v4name, v4src6)) {
1038 return; /* source appears fake, drop */
1041 * Distinguish types of traffic:
1042 * Non-plain, Plain Unicast, Plain Multicast
1044 if ((v4v6nexthdr == IPPROTO_ICMPV6) &&
1045 (v4v6icmptype >= 133) && (v4v6icmptype <= 137)) {
1047 // Not Plain: Router Adv/Sol, Neighbor Adv/Sol, Redirect
1048 if (v4v6hoplimit != 255) {
1051 handle_4to6_nd (&v4name, buflen);
1054 // Plain Unicast or Plain Multicast (both may enter)
1055 if (v4v6hoplimit-- <= 1) {
1058 handle_4to6_plain (buflen, &v4name);
1064 * Relay an IPv6 package to 6bed4, using the link-local address as it
1065 * is found in the Ethernet header. Trust the local IPv6 stack to have
1066 * properly obtained this destination address through Neighbor Discovery
1069 void handle_6to4_plain_unicast (const ssize_t pktlen, const uint8_t *lladdr) {
1070 struct sockaddr_in v4dest;
1071 memset (&v4dest, 0, sizeof (v4dest));
1072 v4dest.sin_family = AF_INET;
1073 v4dest.sin_port = htons (lladdr [0] | (lladdr [1] << 8));
1074 memcpy (&v4dest.sin_addr, lladdr + 2, 4);
1075 if (v6tc != (v6hdr6->ip6_vfc & htonl (0x0ff00000))) {
1076 v6tc = v6hdr6->ip6_vfc & htonl (0x0ff00000);
1077 v4qos = (ntohl (v6hdr6->ip6_vfc) & 0x0ff00000) >> 24;
1078 if (setsockopt (v4sox, IPPROTO_IP, IP_TOS, &v4qos, sizeof (v4qos)) == -1) {
1079 syslog (LOG_ERR, "Failed to switch IPv4 socket to QoS setting 0x%02x\n", v4qos);
1082 syslog (LOG_DEBUG, "%s: Sending IPv6-UDP-IPv4 to %d.%d.%d.%d:%d, result = %zd\n", program,
1083 ((uint8_t *) &v4dest.sin_addr.s_addr) [0],
1084 ((uint8_t *) &v4dest.sin_addr.s_addr) [1],
1085 ((uint8_t *) &v4dest.sin_addr.s_addr) [2],
1086 ((uint8_t *) &v4dest.sin_addr.s_addr) [3],
1087 ntohs (v4dest.sin_port),
1090 pktlen - sizeof (struct ethhdr),
1092 (struct sockaddr *) &v4dest,
1093 sizeof (struct sockaddr_in))
1100 * Handle a request for Neighbor Discovery over the 6bed4 Link.
1102 void handle_6to4_nd (ssize_t pktlen) {
1105 // Validate ICMPv6 message -- trivial, trust local generation
1107 // Handle the message dependent on its type
1108 switch (v6icmp6type) {
1109 case ND_ROUTER_SOLICIT:
1110 v6icmp6type = ND_ROUTER_ADVERT;
1112 v6icmp6data [0] = 0; // Cur Hop Limit: unspec
1113 v6icmp6data [1] = 0x18; // M=0, O=0,
1116 //TODO: wire says 0x44 for router_adv.flags
1117 size_t writepos = 2;
1118 memset (v6icmp6data + writepos,
1119 default_route? 0xff: 0x00,
1120 2); // Router Lifetime
1122 memcpy (v6icmp6data + writepos,
1124 4); // Reachable Time: 32s
1126 memcpy (v6icmp6data + writepos,
1128 4); // Retrans Timer: .25s
1130 writepos = icmp6_prefix (writepos, 0);
1131 v6plen = htons (4 + writepos);
1132 memcpy (v6dst6, v6src6, 16);
1133 memcpy (v6src6, v6listen_linklocal_complete, 16);
1134 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 4 + writepos);
1135 v6ether.h_proto = htons (ETH_P_IPV6);
1136 memcpy (v6ether.h_dest, v6ether.h_source, 6);
1137 memcpy (v6ether.h_source, v6lladdr, 6);
1138 syslog (LOG_INFO, "Replying Router Advertisement to the IPv6 Link, result = %zd\n",
1139 write (v6sox, &v6data6, sizeof (struct ethhdr) + sizeof (struct ip6_hdr) + 4 + writepos)
1143 case ND_ROUTER_ADVERT:
1144 return; /* the IPv6 Link is no router, drop */
1145 case ND_NEIGHBOR_SOLICIT:
1147 // Neighbor Solicitation is treated depending on its kind:
1148 // - the 6bed4 Router address is answered immediately
1149 // - discovery for the local IPv6 address is dropped
1150 // - discovery for fe80::/64 addresses is answered
1151 // - other peers start a process in the ndqueue
1152 if ((memcmp (v6ndtarget, router_linklocal_address, 16) == 0) ||
1153 (memcmp (v6ndtarget, router_linklocal_address_complete, 16) == 0)) {
1154 advertise_6bed4_public_service (NULL);
1155 } else if (memcmp (v6ndtarget, &v6listen, 16) == 0) {
1156 return; /* yes you are unique, drop */
1157 } else if (memcmp (v6ndtarget, v6listen_linklocal, 8) == 0) {
1159 // Construct response for fe80::/64
1160 v6icmp6type = ND_NEIGHBOR_ADVERT;
1161 v6icmp6data [0] = 0x60; /* Solicited, Override */
1162 v6icmp6data [20] = 2; /* Target Link-Layer Address */
1163 v6icmp6data [21] = 1; /* Length is 1x 8 bytes */
1164 v6icmp6data [22] = v6icmp6data [12] ^ 0x02;
1165 v6icmp6data [23] = v6icmp6data [13];
1166 v6icmp6data [24] = v6icmp6data [14];
1167 v6icmp6data [25] = v6icmp6data [17];
1168 v6icmp6data [26] = v6icmp6data [18];
1169 v6icmp6data [27] = v6icmp6data [19];
1170 v6plen = htons (4 + 28);
1171 memcpy (v6dst6, v6src6, 16);
1172 memcpy (v6src6, &v6listen, 16);
1173 memcpy (v6ether.h_dest, v6ether.h_source, 6);
1174 memcpy (v6ether.h_source, v6lladdr, 6);
1175 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 4 + 28);
1176 syslog (LOG_DEBUG, "Sending trivial reply to fe80::/64 type query\n");
1177 write (v6sox, &v6data6, sizeof (struct ethhdr) + sizeof (struct ip6_hdr) + 4 + 28);
1180 enqueue ((struct in6_addr *) v6ndtarget, (struct in6_addr *) v6src6, v6ether.h_source);
1183 case ND_NEIGHBOR_ADVERT:
1184 lldest [0] = v6dst6->s6_addr [8] ^ 0x02;
1185 lldest [1] = v6dst6->s6_addr [9];
1186 lldest [2] = v6dst6->s6_addr [10];
1187 lldest [3] = v6dst6->s6_addr [13];
1188 lldest [4] = v6dst6->s6_addr [14];
1189 lldest [5] = v6dst6->s6_addr [15];
1190 handle_6to4_plain_unicast (pktlen, lldest);
1193 //TODO:NOT_IMPLEMENTED_YET:ND_REDIRECT_FROM_6BED4//
1195 // Redirect indicates that a more efficient bypass exists than
1196 // the currently used route. The remote peer has established
1197 // this and wants to share that information to retain a
1198 // symmetric communication, which is helpful in keeping holes
1199 // in NAT and firewalls open.
1207 * Receive an IPv6 package, check its address and pickup IPv4 address and
1208 * port, then package it as a tunnel message and forward it to IPv4:port.
1209 * Rely on the proper formatting of the incoming IPv6 packet, as it is
1210 * locally generated.
1212 void handle_6to4 (void) {
1214 // Receive the IPv6 package and ensure a consistent size
1215 size_t rawlen = read (v6sox, &v6data6, sizeof (v6data6));
1217 return; /* failure to read, drop */
1219 if (rawlen < sizeof (struct ethhdr) + sizeof (struct ip6_hdr) + 1) {
1220 return; /* packet too small, drop */
1222 if (v6ether.h_proto != htons (ETH_P_IPV6)) {
1223 return; /* not IPv6, drop */
1225 //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]);
1227 // Ignore messages from the IPv6 stack to itself
1228 if (memcmp (v6ether.h_dest, v6ether.h_source, 6) == 0) {
1229 syslog (LOG_DEBUG, "TODO: Self-to-self messaging in IPv6 stack ignored\n");
1233 * Distinguish types of traffic:
1234 * Non-plain, Plain Unicast, Plain Multicast
1236 if ((v6type == IPPROTO_ICMPV6) &&
1237 (v6icmp6type >= 133) && (v6icmp6type <= 137)) {
1239 // Not Plain: Router Adv/Sol, Neighbor Adv/Sol, Redirect
1240 syslog (LOG_DEBUG, "Forwarding non-plain unicast from IPv6 to 6bed4\n");
1241 handle_6to4_nd (rawlen);
1242 } else if ((v6dst6->s6_addr [0] != 0xff) && !(v6dst6->s6_addr [8] & 0x01)) {
1245 if (v6hops-- <= 1) {
1248 syslog (LOG_DEBUG, "Forwarding plain unicast from IPv6 to 6bed4\n");
1249 handle_6to4_plain_unicast (rawlen, v6ether.h_dest);
1253 //TODO:IGNORE_MULTICAST//
1254 //TODO// syslog (LOG_DEBUG, "%s: Plain multicast from 6bed4 Link to 6bed4 Network is not supported\n", program);
1260 * Send a single Neighbor Solicitation message over 6bed4. This will
1261 * be sent to the given 6bed4 address, and is usually part of a series
1262 * of attempts to find a short-cut route to the 6bed4 peer.
1264 void solicit_6bed4_neighbor (const struct ndqueue *info, const uint8_t *addr6bed4) {
1265 memcpy (v6src6, &info->source, 16);
1266 memcpy (v6dst6, &info->target, 16);
1267 v6type = IPPROTO_ICMPV6;
1269 v6icmp6type = ND_NEIGHBOR_SOLICIT;
1274 v6icmp6data [3] = 0x00;
1275 memcpy (v6icmp6data + 4, &info->target, 16);
1276 v6icmp6data [20] = 1; // option type is Source Link-Layer Address
1277 v6icmp6data [21] = 1; // option length is 1x 8 bytes
1278 memcpy (v6icmp6data + 22, v6lladdr, 6);
1279 uint16_t pktlen = sizeof (struct ip6_hdr) + 4 + 28;
1280 //OLD// v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 28 + 8);
1281 v6plen = htons (4 + 28);
1282 v6icmp6csum = icmp6_checksum ((uint8_t *) v6hdr6, 4 + 28);
1283 handle_6to4_plain_unicast (sizeof (struct ip6_hdr) + 8 + 28 + 10, addr6bed4);
1284 //TODO// Why these +8 and +10 are needed, I don't know yet!
1289 * Find a neighbor's 6bed4 address. This is coordinated by the ndqueue,
1290 * which schedules such tasks and makes them repeat. Furthermore, a few
1291 * attempts may be scheduled on the local network before attempts
1292 * shift to the direct target IPv4/UDP addresses. Of course the local
1293 * network will only be scheduled if the public IPv4 address matches
1294 * the one for the local node.
1296 * This process is dequeued by reverse Neighbor Advertisements. If none
1297 * comes back in spite of the various Neighbor Solicitations sent, then
1298 * the final action is to send a Neighbor Advertisement to the host with
1299 * the Public 6bed4 Service as its target of last resort. In case of
1300 * this last resort, the process is not continued any further; the
1301 * return value indicates whether the queue entry should be kept for
1304 bool chase_neighbor_6bed4_address (struct ndqueue *info) {
1305 uint8_t addr6bed4 [6];
1306 static const uint8_t addr6bed4_lancast [8] = {
1307 UDP_PORT_6BED4 & 0xff, UDP_PORT_6BED4 >> 8,
1310 if (info->todo_lancast > 0) {
1311 // Attempt 1. Send to LAN multicast address (same public IP)
1312 info->todo_lancast--;
1313 solicit_6bed4_neighbor (info, addr6bed4_lancast);
1315 } else if (info->todo_direct > 0) {
1316 // Attempt 2. Send to target's direct IP address / UDP port
1317 info->todo_direct--;
1318 addr6bed4 [0] = info->target.s6_addr [8] ^ 0x02;
1319 addr6bed4 [1] = info->target.s6_addr [9];
1320 addr6bed4 [2] = info->target.s6_addr [10];
1321 addr6bed4 [3] = info->target.s6_addr [13];
1322 addr6bed4 [4] = info->target.s6_addr [14];
1323 addr6bed4 [5] = info->target.s6_addr [15];
1324 solicit_6bed4_neighbor (info, addr6bed4);
1327 // Attempt 3. Respond with Public 6bed4 Service
1328 syslog (LOG_INFO, "%s: Failed to find a bypass, passing back the 6bed4 Router\n", program);
1329 advertise_6bed4_public_service (info);
1336 * Perform Router Solicitation. This is the usual mechanism that is used
1337 * on ethernet links as well, except that the 6bed4 permits fixed interface
1338 * identifiers; for this client, the interface identifier will be 0x0001.
1339 * The router always has interface identifier 0x0000 but it will now be
1340 * addressed at the all-routers IPv6 address 0xff02::2 with the general
1341 * source IPv6 address ::
1343 void solicit_router (void) {
1344 v4name.sin_family = AF_INET;
1345 memcpy (&v4name.sin_addr.s_addr, &v4listen, 4);
1346 v4name.sin_port = htons (UDP_PORT_6BED4);
1349 // syslog (LOG_DEBUG, "%s: Sending RouterSolicitation-IPv6-UDP-IPv4 to %d.%d.%d.%d:%d, result = %d\n", program,
1350 // ((uint8_t *) &v4name.sin_addr.s_addr) [0],
1351 // ((uint8_t *) &v4name.sin_addr.s_addr) [1],
1352 // ((uint8_t *) &v4name.sin_addr.s_addr) [2],
1353 // ((uint8_t *) &v4name.sin_addr.s_addr) [3],
1354 // ntohs (v4name.sin_port),
1357 ipv6_router_solicitation,
1358 sizeof (ipv6_router_solicitation),
1360 (struct sockaddr *) &v4name, sizeof (v4name)));
1365 * Send a KeepAlive message. This is an UDP/IPv4 message with no contents.
1366 * The router will not respond, but that is okay; outgoing traffic is the
1367 * way to keep holes in NAT and firewalls open.
1369 void keepalive (void) {
1370 v4name.sin_family = AF_INET;
1371 memcpy (&v4name.sin_addr.s_addr, &v4listen, 4);
1372 v4name.sin_port = htons (UDP_PORT_6BED4);
1375 setsockopt (v4sox, IPPROTO_IP, IP_TTL, &keepalive_ttl, sizeof (keepalive_ttl));
1380 (struct sockaddr *) &v4name, sizeof (v4name));
1381 setsockopt (v4sox, IPPROTO_IP, IP_TTL, &v4ttl, sizeof (v4ttl));
1385 /* Regular maintenance is a routine that runs regularly to do one of two
1386 * generic tasks: either it sends Router Solicitation messages to the
1387 * Public 6bed4 Service, or it sends an empty UDP message somewhat in its
1388 * direction to keep NAT/firewall holes open.
1390 void regular_maintenance (void) {
1393 maintenance_time_cycle <<= 1;
1394 maintenance_time_cycle += 1;
1395 if (maintenance_time_cycle > maintenance_time_cycle_max) {
1396 maintenance_time_cycle = maintenance_time_cycle_max;
1398 syslog (LOG_INFO, "Sent Router Advertisement to Public 6bed4 Service, next attempt in %ld seconds\n", maintenance_time_cycle);
1400 syslog (LOG_INFO, "Sending a KeepAlive message (empty UDP) to the 6bed4 Router\n");
1402 maintenance_time_cycle = maintenance_time_cycle_max;
1404 maintenance_time_sec = time (NULL) + maintenance_time_cycle;
1408 /* Run the daemon core code, passing information between IPv4 and IPv6 and
1409 * responding to tunnel requests if so requested.
1411 void run_daemon (void) {
1414 maintenance_time_sec = 0; // trigger Router Solicitation
1416 FD_SET (v4sox, &io);
1417 FD_SET (v6sox, &io);
1418 int nfds = (v4sox < v6sox)? (v6sox + 1): (v4sox + 1);
1419 if (v4mcast != -1) {
1420 FD_SET (v4mcast, &io);
1421 if (v4mcast >= nfds) {
1426 struct timeval tout;
1428 gettimeofday (&now, NULL);
1429 if (maintenance_time_sec <= now.tv_sec) {
1430 regular_maintenance ();
1432 tout.tv_sec = maintenance_time_sec - now.tv_sec;
1435 ((ndqueue->next->tv.tv_sec == now.tv_sec)
1436 && (ndqueue->next->tv.tv_usec <= now.tv_usec))
1437 || (ndqueue->next->tv.tv_sec < now.tv_sec))) {
1439 // Run the entry's handler code
1440 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);
1441 keep = chase_neighbor_6bed4_address (ndqueue->next);
1443 dequeue (ndqueue->next);
1447 // Make ndqueue point to the entry to run
1448 ndqueue = ndqueue->next;
1450 // Add 50ms to the running time
1451 if (now.tv_usec < 950000) {
1452 ndqueue->tv.tv_usec = now.tv_usec + 50000;
1453 ndqueue->tv.tv_sec = now.tv_sec + 0;
1455 ndqueue->tv.tv_usec = now.tv_usec - 950000;
1456 ndqueue->tv.tv_sec = now.tv_sec + 1;
1459 if (ndqueue && ((ndqueue->next->tv.tv_sec - now.tv_sec) < tout.tv_sec)) {
1460 tout.tv_sec = ndqueue->next->tv.tv_sec - now.tv_sec ;
1461 tout.tv_usec = ndqueue->next->tv.tv_usec - now.tv_usec;
1462 if (tout.tv_usec < 0) {
1463 tout.tv_usec += 1000000;
1467 if (select (nfds, &io, NULL, NULL, &tout) == -1) {
1468 syslog (LOG_ERR, "Select failed: %s\n", strerror (errno));
1470 if (FD_ISSET (v4sox, &io)) {
1471 syslog (LOG_DEBUG, "Got unicast input\n");
1472 handle_4to6 (v4sox);
1474 FD_SET (v4sox, &io);
1476 if (FD_ISSET (v6sox, &io)) {
1479 FD_SET (v6sox, &io);
1481 if (v4mcast != -1) {
1482 if (FD_ISSET (v4mcast, &io)) {
1483 syslog (LOG_DEBUG, "WOW: Got multicast input\n");
1484 handle_4to6 (v4mcast);
1486 FD_SET (v4mcast, &io);
1494 /* Option descriptive data structures */
1496 char *short_opt = "s:t:dl:p:r:k:feh";
1498 struct option long_opt [] = {
1499 { "v4server", 1, NULL, 's' },
1500 { "tundev", 1, NULL, 't' },
1501 { "default-route", 0, NULL, 'd' },
1502 { "listen", 1, NULL, 'l' },
1503 { "port", 1, NULL, 'p' },
1504 { "radius-multicast", 1, NULL, 'r' },
1505 { "foreground", 0, NULL, 'f' },
1506 { "fork-not", 0, NULL, 'f' },
1507 { "keepalive", 1, NULL, 'k' },
1508 { "keepalive-period-ttl", 1, NULL, 'k' },
1509 { "error-console", 0, NULL, 'e' },
1510 { "help", 0, NULL, 'h' },
1511 { NULL, 0, NULL, 0 } /* Array termination */
1515 /* Parse commandline arguments (and start to process them).
1516 * Return 1 on success, 0 on failure.
1518 int process_args (int argc, char *argv []) {
1522 unsigned long tmpport;
1524 default_route = false;
1526 switch (getopt_long (argc, argv, short_opt, long_opt, NULL)) {
1529 if (optind != argc) {
1530 fprintf (stderr, "%s: Extra arguments not permitted: %s...\n", program, argv [optind]);
1537 fprintf (stderr, "%s: You can only specify a single server address\n", program);
1541 if (inet_pton (AF_INET, optarg, &v4peer.sin_addr) <= 0) {
1543 fprintf (stderr, "%s: Failed to parse IPv4 address %s\n", program, optarg);
1546 memcpy (&v4listen, &v4peer.sin_addr, 4);
1547 v4sox = socket (AF_INET, SOCK_DGRAM, 0);
1550 fprintf (stderr, "%s: Failed to allocate UDPv4 socket: %s\n", program, strerror (errno));
1557 fprintf (stderr, "%s: Multiple -t arguments are not permitted\n", program);
1560 v6sox = open (optarg, O_RDWR);
1563 fprintf (stderr, "%s: Failed to open tunnel device %s: %s\n", program, optarg, strerror (errno));
1568 if (default_route) {
1569 fprintf (stderr, "%s: You can only request default route setup once\n", program);
1572 default_route = true;
1575 if (inet_pton (AF_INET, optarg, &v4bind.sin_addr.s_addr) != 1) {
1576 fprintf (stderr, "%s: IPv4 address %s is not valid\n", program, optarg);
1581 tmpport = strtoul (optarg, &endarg, 10);
1582 if ((*endarg) || (tmpport > 65535)) {
1583 fprintf (stderr, "%s: UDP port number %s is not valid\n", program, optarg);
1586 if (tmpport & 0x0001) {
1587 fprintf (stderr, "%s: UDP port number %ld is odd, which is not permitted\n", program, tmpport);
1590 v4bind.sin_port = htons (tmpport);
1594 fprintf (stderr, "%s: You can only request foreground operation once\n", program);
1600 if (log_to_stderr) {
1601 fprintf (stderr, "%s: You can only specify logging to stderr once\n", program);
1604 log_to_stderr = true;
1607 if (v4ttl_mcast != -1) {
1608 fprintf (stderr, "%s: You can set the radius for multicast once\n", program);
1612 long setting = strtol(optarg, &zero, 10);
1613 if (*zero || (setting < 0) || (setting > 255)) {
1614 fprintf (stderr, "%s: Multicast radius must be a number in the range 0 to 255, inclusive, not %s\n", program, optarg);
1617 v4ttl_mcast = setting;
1620 if (keepalive_ttl != -1) {
1621 fprintf (stderr, "%s: You can only set the keepalive period and TTL once\n", program);
1625 keepalive_period = strtol (optarg, &rest, 10);
1628 keepalive_ttl = strtol (rest, &rest, 10);
1629 if ((keepalive_ttl < 0) || (keepalive_ttl > 255)) {
1630 fprintf (stderr, "%s: The keepalive TTL must be in the range 0 to 255, inclusive\n", program);
1637 fprintf (stderr, "%s: The format for keepalive configuration is 'period,ttl' or just 'period', but not %s\n", program, optarg);
1644 /* continue into 'h' to produce usage information */
1654 #ifdef HAVE_SETUP_TUNNEL
1655 fprintf (stderr, "Usage: %s [-d] [-t /dev/tunX]\n %s -h\n", program, program);
1657 fprintf (stderr, "Usage: %s [-d] -t /dev/tunX\n %s -h\n", program, program);
1664 if (keepalive_ttl != -1) {
1665 maintenance_time_cycle_max = keepalive_period;
1669 #ifdef HAVE_SETUP_TUNNEL
1671 if (geteuid () != 0) {
1672 fprintf (stderr, "%s: You should be root, or use -t to specify an accessible tunnel device\n", program);
1675 return setup_tunnel ();
1678 #else /* ! HAVE_SETUP_TUNNEL */
1680 fprintf (stderr, "%s: You must specify a tunnel device with -t that is accessible to you\n", program);
1683 #endif /* HAVE_SETUP_TUNNEL */
1688 /* The main program parses commandline arguments and forks off the daemon
1690 int main (int argc, char *argv []) {
1693 program = strrchr (argv [0], '/');
1699 memset (&v4name, 0, sizeof (v4name));
1700 memset (&v4peer, 0, sizeof (v4peer));
1701 memset (&v6name, 0, sizeof (v6name));
1702 v4name.sin_family = AF_INET ;
1703 v4peer.sin_family = AF_INET ;
1704 v6name.sin6_family = AF_INET6;
1705 // Fixed public server data, IPv4 and UDP:
1706 v4server = SERVER_6BED4_IPV4_TXT;
1707 v4peer.sin_addr.s_addr = htonl (SERVER_6BED4_IPV4_INT32);
1708 v4name.sin_port = htons (UDP_PORT_6BED4);
1709 v4peer.sin_port = htons (UDP_PORT_6BED4);
1710 memcpy (&v4listen, &v4peer.sin_addr, 4);
1711 memset (&v4bind, 0, sizeof (v4bind));
1712 v4bind.sin_family = AF_INET;
1714 // Parse commandline arguments
1715 if (!process_args (argc, argv)) {
1719 // Construct the 6bed4 Router's complete link-layer address
1720 router_linklocal_address_complete [8] = (ntohs (v4peer.sin_port) & 0xff) ^ 0x02;
1721 router_linklocal_address_complete [9] = ntohs (v4peer.sin_port) >> 8;
1722 router_linklocal_address_complete [10] = ntohl (v4peer.sin_addr.s_addr) >> 24;
1723 router_linklocal_address_complete [11] = 0xff;
1724 router_linklocal_address_complete [12] = 0xfe;
1725 memcpy (router_linklocal_address_complete + 13, &((uint8_t *) &v4peer.sin_addr) [1], 3);
1727 // Open the syslog channel
1728 openlog (program, LOG_NDELAY | LOG_PID | ( log_to_stderr? LOG_PERROR: 0), LOG_DAEMON);
1730 // Create memory for the freequeue buffer
1731 freequeue = calloc (freequeue_items, sizeof (struct ndqueue));
1733 syslog (LOG_CRIT, "%s: Failed to allocate %d queue items\n", program, freequeue_items);
1737 for (i = 1; i < freequeue_items; i++) {
1738 freequeue [i].next = &freequeue [i-1];
1740 freequeue = &freequeue [freequeue_items - 1];
1742 // Create socket for normal outgoing (and return) 6bed4 traffic
1744 v4sox = socket (AF_INET, SOCK_DGRAM, 0);
1746 syslog (LOG_CRIT, "%s: Failed to open a local IPv4 socket -- does your system still support IPv4?\n", program);
1750 struct sockaddr_in tmpaddr;
1751 memset (&tmpaddr, 0, sizeof (tmpaddr));
1752 tmpaddr.sin_family = AF_INET;
1754 uint16_t portn = rand () & 0x3ffe;
1755 uint16_t port0 = portn + 16384;
1756 //TODO// Move port iteration + allocation to separate function
1757 while (portn < port0) {
1758 tmpaddr.sin_port = htons ((portn & 0x3ffe) + 49152);
1759 if (bind (v4sox, (struct sockaddr *) &tmpaddr, sizeof (tmpaddr)) == 0) {
1764 if (portn < port0) {
1765 syslog (LOG_DEBUG, "Bound to UDP port %d\n", ntohs (tmpaddr.sin_port));
1767 fprintf (stderr, "%s: All even dynamic ports rejected binding: %s\n", program, strerror (errno));
1771 // Setup fragmentation, QoS and TTL options
1775 if (setsockopt (v4sox, IPPROTO_IP, IP_DONTFRAG, no, sizeof (no)) == -1) {
1776 syslog (LOG_ERR, "Failed to permit fragmentation -- not all peers may be accessible with MTU 1280");
1779 #warning "Target system lacks support for controlling packet fragmentation"
1781 socklen_t soxlen = sizeof (v4qos);
1782 if (getsockopt (v4sox, IPPROTO_IP, IP_TOS, &v4qos, &soxlen) == -1) {
1783 syslog (LOG_ERR, "Quality of Service is not supported by the IPv4-side socket");
1786 v6tc = htonl (v4qos << 20);
1787 soxlen = sizeof (v4ttl);
1788 if (getsockopt (v4sox, IPPROTO_IP, IP_TTL, &v4ttl, &soxlen) == -1) {
1789 syslog (LOG_ERR, "Time To Live cannot be varied on the IPv4 socket");
1793 // Bind to the IPv4 all-nodes local multicast address
1794 memset (&v4allnodes, 0, sizeof (v4allnodes));
1795 v4allnodes.sin_family = AF_INET;
1796 v4allnodes.sin_port = htons (UDP_PORT_6BED4);
1797 v4allnodes.sin_addr.s_addr = htonl ( INADDR_ANY );
1799 v4mcast = socket (AF_INET, SOCK_DGRAM, 0);
1800 if (v4mcast != -1) {
1801 struct ip_mreq mreq;
1802 mreq.imr_multiaddr.s_addr = htonl ( (224L << 24) | 1L);
1803 mreq.imr_multiaddr.s_addr = htonl ( INADDR_ANY );
1804 if (bind (v4mcast, (struct sockaddr *) &v4allnodes, sizeof (v4allnodes)) != 0) {
1807 syslog (LOG_ERR, "No LAN bypass: Failed to bind to IPv4 all-nodes: %s\n", strerror (errno));
1808 } else if (setsockopt (v4mcast, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof (yes)) == -1) {
1811 syslog (LOG_ERR, "No LAN bypass: Failed to share multicast port: %s\n", strerror (errno));
1812 } else if (setsockopt (v4mcast, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof (mreq)) == -1) {
1815 syslog (LOG_ERR, "No LAN bypass: Failed to setup multicast: %s\n", strerror (errno));
1816 } else if ((v4ttl_mcast != -1) && (setsockopt (v4mcast, IPPROTO_IP, IP_MULTICAST_TTL, &v4ttl_mcast, sizeof (v4ttl_mcast)) == -1)) {
1819 syslog (LOG_ERR, "No LAN bypass: Failed to configure the multicast radius: %s\n", strerror (errno));
1822 if (bind (v4mcast, (struct sockaddr *) &v4allnodes, sizeof (v4allnodes)) != 0) {
1825 syslog (LOG_ERR, "%s: No LAN bypass: Failed to bind to IPv4 all-nodes\n", program);
1826 } else if (listen (v4mcast, 10) != 0) {
1829 syslog (LOG_ERR, "%s: No LAN bypass: Failed to listen to IPv4 all-nodes\n", program);
1834 syslog (LOG_INFO, "%s: No LAN bypass: Not desired\n", program);
1837 // Construct an rtnetlink socket for neighbor cache interaction
1838 rtsox = socket (PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
1840 syslog (LOG_CRIT, "Failed to gain access to the neighbor cache: %s\n", strerror (errno));
1843 memset (&rtname, 0, sizeof (rtname ));
1844 memset (&rtkernel, 0, sizeof (rtkernel));
1845 rtname.nl_family = rtkernel.nl_family = AF_NETLINK;
1846 rtname.nl_pid = getpid ();
1847 if (bind (rtsox, (struct sockaddr *) &rtname, sizeof (rtname)) == -1) {
1848 syslog (LOG_CRIT, "Failed to bind to the neighbor cache socket: %s\n", strerror (errno));
1851 if (connect (rtsox, (struct sockaddr *) &rtkernel, sizeof (rtkernel)) == -1) {
1852 syslog (LOG_CRIT, "Failed to connect to the neighbor cachr in the kernel; %s\n", strerror (errno));
1855 { uint8_t testll [6];
1856 uint8_t test_address [] = { 0xfe, 0x80, 0,0,0,0,0,0, 0xc2, 0x25, 0x06, 0xff, 0xfe, 0xb0, 0x7e, 0xa6 };
1857 if (lookup_neighbor (test_address, testll)) {
1858 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]);
1859 } else { syslog (LOG_INFO, "Failed to find LL\n"); } }
1861 // If port and/or listen arguments were provided, bind to them
1862 if ((v4bind.sin_addr.s_addr != INADDR_ANY) || (v4bind.sin_port != 0)) {
1863 if (bind (v4sox, (struct sockaddr *) &v4bind, sizeof (v4bind)) != 0) {
1864 syslog (LOG_CRIT, "%s: Failed to bind to local socket -- did you specify both address and port?\n", program);
1873 if (setsid () != -1) {
1874 syslog (LOG_CRIT, "%s: Failure to detach from parent session: %s\n", program, strerror (errno));
1879 syslog (LOG_CRIT, "%s: Failure to fork daemon process: %s\n", program, strerror (errno));
1883 if (! log_to_stderr) {
1894 // Report successful creation of the daemon