2 * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License v2 as published by
6 * the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
23 #include <arpa/inet.h>
24 #include <net/route.h>
30 static void forward_router_solicitation(const struct interface
*iface
);
31 static void forward_router_advertisement(uint8_t *data
, size_t len
);
33 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
34 struct interface
*iface
, void *dest
);
35 static void trigger_router_advert(struct uloop_timeout
*event
);
36 static void sigusr1_refresh(int signal
);
38 static struct odhcpd_event router_event
= {.uloop
= {.fd
= -1}, .handle_dgram
= handle_icmpv6
, };
40 static FILE *fp_route
= NULL
;
43 #define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
48 int sock
= socket(AF_INET6
, SOCK_RAW
| SOCK_CLOEXEC
, IPPROTO_ICMPV6
);
49 if (sock
< 0 && errno
!= EAFNOSUPPORT
) {
50 syslog(LOG_ERR
, "Failed to open RAW-socket: %s", strerror(errno
));
54 // Let the kernel compute our checksums
56 setsockopt(sock
, IPPROTO_RAW
, IPV6_CHECKSUM
, &val
, sizeof(val
));
58 // This is required by RFC 4861
60 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_HOPS
, &val
, sizeof(val
));
61 setsockopt(sock
, IPPROTO_IPV6
, IPV6_UNICAST_HOPS
, &val
, sizeof(val
));
63 // We need to know the source interface
65 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVPKTINFO
, &val
, sizeof(val
));
66 setsockopt(sock
, IPPROTO_IPV6
, IPV6_RECVHOPLIMIT
, &val
, sizeof(val
));
70 setsockopt(sock
, IPPROTO_IPV6
, IPV6_MULTICAST_LOOP
, &val
, sizeof(val
));
72 // Filter ICMPv6 package types
73 struct icmp6_filter filt
;
74 ICMP6_FILTER_SETBLOCKALL(&filt
);
75 ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT
, &filt
);
76 ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT
, &filt
);
77 setsockopt(sock
, IPPROTO_ICMPV6
, ICMP6_FILTER
, &filt
, sizeof(filt
));
80 router_event
.uloop
.fd
= sock
;
81 odhcpd_register(&router_event
);
83 if (!(fp_route
= fopen("/proc/net/ipv6_route", "r")))
84 syslog(LOG_ERR
, "Failed to open routing table: %s",
87 signal(SIGUSR1
, sigusr1_refresh
);
92 int setup_router_interface(struct interface
*iface
, bool enable
)
94 if (!fp_route
|| router_event
.uloop
.fd
< 0)
97 struct ipv6_mreq all_nodes
= {ALL_IPV6_NODES
, iface
->ifindex
};
98 struct ipv6_mreq all_routers
= {ALL_IPV6_ROUTERS
, iface
->ifindex
};
100 uloop_timeout_cancel(&iface
->timer_rs
);
101 iface
->timer_rs
.cb
= NULL
;
103 if (iface
->ifindex
<= 0)
106 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
107 &all_nodes
, sizeof(all_nodes
));
108 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
, IPV6_DROP_MEMBERSHIP
,
109 &all_routers
, sizeof(all_routers
));
113 trigger_router_advert(&iface
->timer_rs
);
115 void *mreq
= &all_routers
;
117 if (iface
->ra
== RELAYD_RELAY
&& iface
->master
) {
119 forward_router_solicitation(iface
);
120 } else if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
) {
121 iface
->timer_rs
.cb
= trigger_router_advert
;
122 uloop_timeout_set(&iface
->timer_rs
, 1000);
123 ndp_rqs_addr6_dump();
126 if (iface
->ra
== RELAYD_RELAY
|| (iface
->ra
== RELAYD_SERVER
&& !iface
->master
))
127 setsockopt(router_event
.uloop
.fd
, IPPROTO_IPV6
,
128 IPV6_ADD_MEMBERSHIP
, mreq
, sizeof(all_nodes
));
134 // Signal handler to resend all RDs
135 static void sigusr1_refresh(_unused
int signal
)
137 struct interface
*iface
;
138 list_for_each_entry(iface
, &interfaces
, head
)
139 if (iface
->ra
== RELAYD_SERVER
&& !iface
->master
)
140 uloop_timeout_set(&iface
->timer_rs
, 1000);
143 static bool router_icmpv6_valid(struct sockaddr_in6
*source
, uint8_t *data
, size_t len
)
145 struct icmp6_hdr
*hdr
= (struct icmp6_hdr
*)data
;
146 struct icmpv6_opt
*opt
, *end
= (struct icmpv6_opt
*)&data
[len
];
148 /* Hoplimit is already checked in odhcpd_receive_packets */
149 if (len
< sizeof(*hdr
) || hdr
->icmp6_code
)
152 switch (hdr
->icmp6_type
) {
153 case ND_ROUTER_ADVERT
:
154 if (!IN6_IS_ADDR_LINKLOCAL(&source
->sin6_addr
))
157 opt
= (struct icmpv6_opt
*)((struct nd_router_advert
*)data
+ 1);
160 case ND_ROUTER_SOLICIT
:
161 opt
= (struct icmpv6_opt
*)((struct nd_router_solicit
*)data
+ 1);
168 icmpv6_for_each_option(opt
, opt
, end
)
169 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
&&
170 IN6_IS_ADDR_UNSPECIFIED(&source
->sin6_addr
) &&
171 hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
174 // Check all options parsed successfully
179 // Detect whether a default route exists, also find the source prefixes
180 static bool parse_routes(struct odhcpd_ipaddr
*n
, ssize_t len
)
184 char line
[512], ifname
[16];
185 bool found_default
= false;
186 struct odhcpd_ipaddr p
= {IN6ADDR_ANY_INIT
, 0, 0, 0, 0};
187 while (fgets(line
, sizeof(line
), fp_route
)) {
189 if (sscanf(line
, "00000000000000000000000000000000 00 "
190 "%*s %*s %*s %*s %*s %*s %*s %15s", ifname
) &&
191 strcmp(ifname
, "lo")) {
192 found_default
= true;
193 } else if (sscanf(line
, "%8" SCNx32
"%8" SCNx32
"%*8" SCNx32
"%*8" SCNx32
" %hhx %*s "
194 "%*s 00000000000000000000000000000000 %*s %*s %*s %" SCNx32
" lo",
195 &p
.addr
.s6_addr32
[0], &p
.addr
.s6_addr32
[1], &p
.prefix
, &rflags
) &&
196 p
.prefix
> 0 && (rflags
& RTF_NONEXTHOP
) && (rflags
& RTF_REJECT
)) {
197 // Find source prefixes by scanning through unreachable-routes
198 p
.addr
.s6_addr32
[0] = htonl(p
.addr
.s6_addr32
[0]);
199 p
.addr
.s6_addr32
[1] = htonl(p
.addr
.s6_addr32
[1]);
201 for (ssize_t i
= 0; i
< len
; ++i
) {
202 if (n
[i
].prefix
<= 64 && n
[i
].prefix
>= p
.prefix
&&
203 !odhcpd_bmemcmp(&p
.addr
, &n
[i
].addr
, p
.prefix
)) {
204 n
[i
].dprefix
= p
.prefix
;
212 return found_default
;
215 static int calc_adv_interval(struct interface
*iface
, uint32_t minvalid
,
218 uint32_t minival
= iface
->ra_mininterval
;
221 *maxival
= iface
->ra_maxinterval
;
223 if (*maxival
> minvalid
/3)
224 *maxival
= minvalid
/3;
226 if (*maxival
> MaxRtrAdvInterval
)
227 *maxival
= MaxRtrAdvInterval
;
228 else if (*maxival
< 4)
231 if (minival
< MinRtrAdvInterval
)
232 minival
= MinRtrAdvInterval
;
233 else if (minival
> (*maxival
* 3)/4)
234 minival
= (*maxival
>= 9 ? *maxival
/3 : *maxival
);
236 odhcpd_urandom(&msecs
, sizeof(msecs
));
237 msecs
= (labs(msecs
) % ((*maxival
!= minival
) ? (*maxival
- minival
)*1000 : 500)) +
243 static uint16_t calc_ra_lifetime(struct interface
*iface
, uint32_t maxival
)
245 uint16_t lifetime
= 3*maxival
;
247 if (iface
->ra_lifetime
>= 0) {
248 lifetime
= iface
->ra_lifetime
;
249 if (lifetime
< maxival
)
251 else if (lifetime
> 9000)
258 // Router Advert server mode
259 static uint64_t send_router_advert(struct interface
*iface
, const struct in6_addr
*from
)
261 time_t now
= odhcpd_time();
262 int mtu
= iface
->ra_mtu
;
263 int hlim
= iface
->ra_hoplimit
;
266 mtu
= odhcpd_get_interface_config(iface
->ifname
, "mtu");
272 hlim
= odhcpd_get_interface_config(iface
->ifname
, "hop_limit");
275 struct nd_router_advert h
;
276 struct icmpv6_opt lladdr
;
277 struct nd_opt_mtu mtu
;
279 .h
= {{.icmp6_type
= ND_ROUTER_ADVERT
, .icmp6_code
= 0}, 0, 0},
280 .lladdr
= {ND_OPT_SOURCE_LINKADDR
, 1, {0}},
281 .mtu
= {ND_OPT_MTU
, 1, 0, htonl(mtu
)},
285 adv
.h
.nd_ra_curhoplimit
= hlim
;
288 adv
.h
.nd_ra_flags_reserved
= ND_RA_FLAG_OTHER
;
290 if (iface
->managed
>= RELAYD_MANAGED_MFLAG
)
291 adv
.h
.nd_ra_flags_reserved
|= ND_RA_FLAG_MANAGED
;
293 if (iface
->route_preference
< 0)
294 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_LOW
;
295 else if (iface
->route_preference
> 0)
296 adv
.h
.nd_ra_flags_reserved
|= ND_RA_PREF_HIGH
;
298 adv
.h
.nd_ra_reachable
= htonl(iface
->ra_reachabletime
);
299 adv
.h
.nd_ra_retransmit
= htonl(iface
->ra_retranstime
);
301 odhcpd_get_mac(iface
, adv
.lladdr
.data
);
303 // If not currently shutting down
304 struct odhcpd_ipaddr
*addrs
= NULL
;
306 uint32_t minvalid
= UINT32_MAX
;
307 bool default_route
= false;
308 bool valid_prefix
= false;
311 if (iface
->timer_rs
.cb
) {
312 size_t size
= sizeof(*addrs
) * iface
->ia_addr_len
;
313 addrs
= alloca(size
);
314 memcpy(addrs
, iface
->ia_addr
, size
);
316 ipcnt
= iface
->ia_addr_len
;
318 // Check default route
319 if (iface
->default_router
) {
320 default_route
= true;
322 if (iface
->default_router
> 1)
324 } else if (parse_routes(addrs
, ipcnt
))
325 default_route
= true;
329 struct in6_addr dns_pref
, *dns_addr
= &dns_pref
;
332 odhcpd_get_interface_dns_addr(iface
, &dns_pref
);
334 // Construct Prefix Information options
336 struct nd_opt_prefix_info
*pfxs
= NULL
;
338 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
339 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
340 uint32_t preferred
= 0;
343 if (addr
->prefix
> 96 || addr
->valid
<= (uint32_t)now
) {
344 char namebuf
[INET6_ADDRSTRLEN
];
346 inet_ntop(AF_INET6
, addr
, namebuf
, sizeof(namebuf
));
347 syslog(LOG_INFO
, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
348 namebuf
, addr
->prefix
, addr
->valid
, iface
->ifname
);
352 struct nd_opt_prefix_info
*p
= NULL
;
353 for (size_t i
= 0; i
< pfxs_cnt
; ++i
) {
354 if (addr
->prefix
== pfxs
[i
].nd_opt_pi_prefix_len
&&
355 !odhcpd_bmemcmp(&pfxs
[i
].nd_opt_pi_prefix
,
356 &addr
->addr
, addr
->prefix
))
361 struct nd_opt_prefix_info
*tmp
;
363 tmp
= realloc(pfxs
, sizeof(*pfxs
) * (pfxs_cnt
+ 1));
365 syslog(LOG_ERR
, "Realloc failed for RA prefix option on interface %s", iface
->ifname
);
370 p
= &pfxs
[pfxs_cnt
++];
371 memset(p
, 0, sizeof(*p
));
374 if (addr
->preferred
> (uint32_t)now
) {
375 preferred
= TIME_LEFT(addr
->preferred
, now
);
377 if (iface
->ra_useleasetime
&&
378 preferred
> iface
->dhcpv4_leasetime
)
379 preferred
= iface
->dhcpv4_leasetime
;
382 valid
= TIME_LEFT(addr
->valid
, now
);
383 if (iface
->ra_useleasetime
&& valid
> iface
->dhcpv4_leasetime
)
384 valid
= iface
->dhcpv4_leasetime
;
386 if (minvalid
> valid
)
389 if (!IN6_IS_ADDR_ULA(&addr
->addr
) || iface
->default_router
)
392 odhcpd_bmemcpy(&p
->nd_opt_pi_prefix
, &addr
->addr
,
393 (iface
->ra_advrouter
) ? 128 : addr
->prefix
);
394 p
->nd_opt_pi_type
= ND_OPT_PREFIX_INFORMATION
;
395 p
->nd_opt_pi_len
= 4;
396 p
->nd_opt_pi_prefix_len
= (addr
->prefix
< 64) ? 64 : addr
->prefix
;
397 p
->nd_opt_pi_flags_reserved
= 0;
398 if (!iface
->ra_not_onlink
)
399 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_ONLINK
;
400 if (iface
->managed
< RELAYD_MANAGED_NO_AFLAG
&& addr
->prefix
<= 64)
401 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_AUTO
;
402 if (iface
->ra_advrouter
)
403 p
->nd_opt_pi_flags_reserved
|= ND_OPT_PI_FLAG_RADDR
;
404 p
->nd_opt_pi_preferred_time
= htonl(preferred
);
405 p
->nd_opt_pi_valid_time
= htonl(valid
);
408 // Calculate periodic transmit
410 int msecs
= calc_adv_interval(iface
, minvalid
, &maxival
);
414 syslog(LOG_WARNING
, "A default route is present but there is no public prefix "
415 "on %s thus we don't announce a default route!", iface
->ifname
);
416 adv
.h
.nd_ra_router_lifetime
= 0;
418 adv
.h
.nd_ra_router_lifetime
= htons(calc_ra_lifetime(iface
, maxival
));
421 adv
.h
.nd_ra_router_lifetime
= 0;
423 syslog(LOG_INFO
, "Using a RA lifetime of %d seconds on %s", ntohs(adv
.h
.nd_ra_router_lifetime
), iface
->ifname
);
426 if (iface
->dns_cnt
> 0) {
427 dns_addr
= iface
->dns
;
428 dns_cnt
= iface
->dns_cnt
;
431 if (!dns_addr
|| IN6_IS_ADDR_UNSPECIFIED(dns_addr
))
440 } dns
= {ND_OPT_RECURSIVE_DNS
, (1 + (2 * dns_cnt
)), 0, 0, 0};
442 // DNS Search options
443 uint8_t search_buf
[256], *search_domain
= iface
->search
;
444 size_t search_len
= iface
->search_len
, search_padded
= 0;
446 if (!search_domain
&& !res_init() && _res
.dnsrch
[0] && _res
.dnsrch
[0][0]) {
447 int len
= dn_comp(_res
.dnsrch
[0], search_buf
,
448 sizeof(search_buf
), NULL
, NULL
);
450 search_domain
= search_buf
;
456 search_padded
= ((search_len
+ 7) & (~7)) + 8;
465 } *search
= alloca(sizeof(*search
) + search_padded
);
467 search
->type
= ND_OPT_DNS_SEARCH
;
468 search
->len
= search_len
? ((sizeof(*search
) + search_padded
) / 8) : 0;
471 memcpy(search
->name
, search_domain
, search_len
);
472 memset(&search
->name
[search_len
], 0, search_padded
- search_len
);
475 size_t routes_cnt
= 0;
483 } *tmp
, *routes
= NULL
;
485 for (ssize_t i
= 0; i
< ipcnt
; ++i
) {
486 struct odhcpd_ipaddr
*addr
= &addrs
[i
];
487 if (addr
->dprefix
> 64 || addr
->dprefix
== 0 || addr
->valid
<= (uint32_t)now
||
488 (addr
->dprefix
== 64 && addr
->prefix
== 64)) {
489 continue; // Address not suitable
490 } else if (addr
->dprefix
> 32) {
491 addr
->addr
.s6_addr32
[1] &= htonl(~((1U << (64 - addr
->dprefix
)) - 1));
492 } else if (addr
->dprefix
<= 32) {
493 addr
->addr
.s6_addr32
[0] &= htonl(~((1U << (32 - addr
->dprefix
)) - 1));
494 addr
->addr
.s6_addr32
[1] = 0;
497 tmp
= realloc(routes
, sizeof(*routes
) * (routes_cnt
+ 1));
499 syslog(LOG_ERR
, "Realloc failed for RA route option on interface %s", iface
->ifname
);
505 memset(&routes
[routes_cnt
], 0, sizeof(*routes
));
506 routes
[routes_cnt
].type
= ND_OPT_ROUTE_INFO
;
507 routes
[routes_cnt
].len
= sizeof(*routes
) / 8;
508 routes
[routes_cnt
].prefix
= addr
->dprefix
;
509 routes
[routes_cnt
].flags
= 0;
510 if (iface
->route_preference
< 0)
511 routes
[routes_cnt
].flags
|= ND_RA_PREF_LOW
;
512 else if (iface
->route_preference
> 0)
513 routes
[routes_cnt
].flags
|= ND_RA_PREF_HIGH
;
514 routes
[routes_cnt
].lifetime
= htonl(TIME_LEFT(addr
->valid
, now
));
515 routes
[routes_cnt
].addr
[0] = addr
->addr
.s6_addr32
[0];
516 routes
[routes_cnt
].addr
[1] = addr
->addr
.s6_addr32
[1];
517 routes
[routes_cnt
].addr
[2] = 0;
518 routes
[routes_cnt
].addr
[3] = 0;
523 search
->lifetime
= htonl(maxival
*10);
524 dns
.lifetime
= search
->lifetime
;
526 struct icmpv6_opt adv_interval
= {
527 .type
= ND_OPT_RTR_ADV_INTERVAL
,
529 .data
= {0, 0, (maxival
*1000) >> 24, (maxival
*1000) >> 16, (maxival
*1000) >> 8, maxival
*1000}
532 struct iovec iov
[RA_IOV_LEN
] = {
534 {pfxs
, pfxs_cnt
* sizeof(*pfxs
)},
535 {routes
, routes_cnt
* sizeof(*routes
)},
536 {&dns
, (dns_cnt
) ? sizeof(dns
) : 0},
537 {dns_addr
, dns_cnt
* sizeof(*dns_addr
)},
538 {search
, search
->len
* 8},
539 {&adv_interval
, adv_interval
.len
* 8}};
540 struct sockaddr_in6 dest
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
542 if (from
&& !IN6_IS_ADDR_UNSPECIFIED(from
))
543 dest
.sin6_addr
= *from
;
545 odhcpd_send(router_event
.uloop
.fd
,
546 &dest
, iov
, ARRAY_SIZE(iov
), iface
);
555 static void trigger_router_advert(struct uloop_timeout
*event
)
557 struct interface
*iface
= container_of(event
, struct interface
, timer_rs
);
558 int msecs
= send_router_advert(iface
, NULL
);
560 // Rearm timer if not shut down
562 uloop_timeout_set(event
, msecs
);
566 // Event handler for incoming ICMPv6 packets
567 static void handle_icmpv6(void *addr
, void *data
, size_t len
,
568 struct interface
*iface
, _unused
void *dest
)
570 struct icmp6_hdr
*hdr
= data
;
571 struct sockaddr_in6
*from
= addr
;
573 if (!router_icmpv6_valid(addr
, data
, len
))
576 if ((iface
->ra
== RELAYD_SERVER
&& !iface
->master
)) { // Server mode
577 if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
)
578 send_router_advert(iface
, &from
->sin6_addr
);
579 } else if (iface
->ra
== RELAYD_RELAY
) { // Relay mode
580 if (hdr
->icmp6_type
== ND_ROUTER_ADVERT
&& iface
->master
)
581 forward_router_advertisement(data
, len
);
582 else if (hdr
->icmp6_type
== ND_ROUTER_SOLICIT
&& !iface
->master
)
583 forward_router_solicitation(odhcpd_get_master_interface());
588 // Forward router solicitation
589 static void forward_router_solicitation(const struct interface
*iface
)
594 struct icmp6_hdr rs
= {ND_ROUTER_SOLICIT
, 0, 0, {{0}}};
595 struct iovec iov
= {&rs
, sizeof(rs
)};
596 struct sockaddr_in6 all_routers
=
597 {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, iface
->ifindex
};
599 syslog(LOG_NOTICE
, "Sending RS to %s", iface
->ifname
);
600 odhcpd_send(router_event
.uloop
.fd
, &all_routers
, &iov
, 1, iface
);
604 // Handler for incoming router solicitations on slave interfaces
605 static void forward_router_advertisement(uint8_t *data
, size_t len
)
607 struct nd_router_advert
*adv
= (struct nd_router_advert
*)data
;
610 uint8_t *end
= data
+ len
;
611 uint8_t *mac_ptr
= NULL
;
612 struct in6_addr
*dns_ptr
= NULL
;
613 size_t dns_count
= 0;
615 struct icmpv6_opt
*opt
;
616 icmpv6_for_each_option(opt
, &adv
[1], end
) {
617 if (opt
->type
== ND_OPT_SOURCE_LINKADDR
) {
618 // Store address of source MAC-address
620 } else if (opt
->type
== ND_OPT_RECURSIVE_DNS
&& opt
->len
> 1) {
621 // Check if we have to rewrite DNS
622 dns_ptr
= (struct in6_addr
*)&opt
->data
[6];
623 dns_count
= (opt
->len
- 1) / 2;
627 syslog(LOG_NOTICE
, "Got a RA");
629 // Indicate a proxy, however we don't follow the rest of RFC 4389 yet
630 adv
->nd_ra_flags_reserved
|= ND_RA_FLAG_PROXY
;
632 // Forward advertisement to all slave interfaces
633 struct sockaddr_in6 all_nodes
= {AF_INET6
, 0, 0, ALL_IPV6_NODES
, 0};
634 struct iovec iov
= {data
, len
};
636 struct interface
*iface
;
637 list_for_each_entry(iface
, &interfaces
, head
) {
638 if (iface
->ra
!= RELAYD_RELAY
|| iface
->master
)
641 // Fixup source hardware address option
643 odhcpd_get_mac(iface
, mac_ptr
);
645 // If we have to rewrite DNS entries
646 if (iface
->always_rewrite_dns
&& dns_ptr
&& dns_count
> 0) {
647 const struct in6_addr
*rewrite
= iface
->dns
;
648 struct in6_addr addr
;
649 size_t rewrite_cnt
= iface
->dns_cnt
;
651 if (rewrite_cnt
== 0) {
652 if (odhcpd_get_interface_dns_addr(iface
, &addr
))
653 continue; // Unable to comply
659 // Copy over any other addresses
660 for (size_t i
= 0; i
< dns_count
; ++i
) {
661 size_t j
= (i
< rewrite_cnt
) ? i
: rewrite_cnt
- 1;
662 dns_ptr
[i
] = rewrite
[j
];
666 odhcpd_send(router_event
.uloop
.fd
, &all_nodes
, &iov
, 1, iface
);