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.
30 #include <arpa/inet.h>
32 #include <netinet/ip6.h>
33 #include <netpacket/packet.h>
34 #include <linux/netlink.h>
36 #include <sys/socket.h>
37 #include <sys/ioctl.h>
38 #include <sys/epoll.h>
39 #include <sys/types.h>
41 #include <sys/syscall.h>
43 #include <libubox/uloop.h>
48 static int ioctl_sock
;
49 static int urandom_fd
= -1;
51 static void sighandler(_unused
int signal
)
56 static void print_usage(const char *app
)
60 " -h, --help Print this help\n"
61 " -l level Specify log level 0..7 (default %d)\n",
66 static bool ipv6_enabled(void)
68 int fd
= socket(AF_INET6
, SOCK_DGRAM
, 0);
78 int main(int argc
, char **argv
)
80 openlog("odhcpd", LOG_PERROR
| LOG_PID
, LOG_DAEMON
);
83 while ((opt
= getopt(argc
, argv
, "hl:")) != -1) {
89 config
.log_level
= (atoi(optarg
) & LOG_PRIMASK
);
90 fprintf(stderr
, "Log level set to %d\n", config
.log_level
);
94 setlogmask(LOG_UPTO(config
.log_level
));
98 syslog(LOG_ERR
, "Must be run as root!");
102 ioctl_sock
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, 0);
107 if ((urandom_fd
= open("/dev/urandom", O_RDONLY
| O_CLOEXEC
)) < 0)
110 signal(SIGUSR1
, SIG_IGN
);
111 signal(SIGINT
, sighandler
);
112 signal(SIGTERM
, sighandler
);
117 if (ipv6_enabled()) {
127 #ifndef DHCPV4_SUPPORT
140 /* Read IPv6 MTU for interface */
141 int odhcpd_get_interface_config(const char *ifname
, const char *what
)
144 const char *sysctl_pattern
= "/proc/sys/net/ipv6/conf/%s/%s";
145 snprintf(buf
, sizeof(buf
), sysctl_pattern
, ifname
, what
);
147 int fd
= open(buf
, O_RDONLY
);
151 ssize_t len
= read(fd
, buf
, sizeof(buf
) - 1);
162 /* Read IPv6 MAC for interface */
163 int odhcpd_get_mac(const struct interface
*iface
, uint8_t mac
[6])
167 memset(&ifr
, 0, sizeof(ifr
));
168 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
) - 1);
169 if (ioctl(ioctl_sock
, SIOCGIFHWADDR
, &ifr
) < 0)
172 memcpy(mac
, ifr
.ifr_hwaddr
.sa_data
, 6);
177 /* Forwards a packet on a specific interface */
178 ssize_t
odhcpd_send(int socket
, struct sockaddr_in6
*dest
,
179 struct iovec
*iov
, size_t iov_len
,
180 const struct interface
*iface
)
182 /* Construct headers */
183 uint8_t cmsg_buf
[CMSG_SPACE(sizeof(struct in6_pktinfo
))] = {0};
184 struct msghdr msg
= {
185 .msg_name
= (void *) dest
,
186 .msg_namelen
= sizeof(*dest
),
188 .msg_iovlen
= iov_len
,
189 .msg_control
= cmsg_buf
,
190 .msg_controllen
= sizeof(cmsg_buf
),
194 /* Set control data (define destination interface) */
195 struct cmsghdr
*chdr
= CMSG_FIRSTHDR(&msg
);
196 chdr
->cmsg_level
= IPPROTO_IPV6
;
197 chdr
->cmsg_type
= IPV6_PKTINFO
;
198 chdr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
199 struct in6_pktinfo
*pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(chdr
);
200 pktinfo
->ipi6_ifindex
= iface
->ifindex
;
202 /* Also set scope ID if link-local */
203 if (IN6_IS_ADDR_LINKLOCAL(&dest
->sin6_addr
)
204 || IN6_IS_ADDR_MC_LINKLOCAL(&dest
->sin6_addr
))
205 dest
->sin6_scope_id
= iface
->ifindex
;
207 char ipbuf
[INET6_ADDRSTRLEN
];
208 inet_ntop(AF_INET6
, &dest
->sin6_addr
, ipbuf
, sizeof(ipbuf
));
210 ssize_t sent
= sendmsg(socket
, &msg
, MSG_DONTWAIT
);
212 syslog(LOG_ERR
, "Failed to send to %s%%%s@%s (%m)",
213 ipbuf
, iface
->name
, iface
->ifname
);
215 syslog(LOG_DEBUG
, "Sent %zd bytes to %s%%%s@%s",
216 sent
, ipbuf
, iface
->name
, iface
->ifname
);
221 static int odhcpd_get_linklocal_interface_address(int ifindex
, struct in6_addr
*lladdr
)
224 struct sockaddr_in6 addr
;
225 socklen_t alen
= sizeof(addr
);
226 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
231 memset(&addr
, 0, sizeof(addr
));
232 addr
.sin6_family
= AF_INET6
;
233 inet_pton(AF_INET6
, ALL_IPV6_ROUTERS
, &addr
.sin6_addr
);
234 addr
.sin6_scope_id
= ifindex
;
236 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
237 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
)) {
238 *lladdr
= addr
.sin6_addr
;
247 * DNS address selection criteria order :
248 * - use IPv6 address with valid lifetime if none is yet selected
249 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
250 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
251 * - use the IPv6 address with the longest preferred lifetime
253 int odhcpd_get_interface_dns_addr(const struct interface
*iface
, struct in6_addr
*addr
)
255 time_t now
= odhcpd_time();
258 for (size_t i
= 0; i
< iface
->addr6_len
; ++i
) {
259 if (iface
->addr6
[i
].valid
<= (uint32_t)now
)
267 if (iface
->addr6
[m
].preferred
>= (uint32_t)now
&&
268 iface
->addr6
[i
].preferred
< (uint32_t)now
)
271 if (IN6_IS_ADDR_ULA(&iface
->addr6
[i
].addr
.in6
)) {
272 if (!IN6_IS_ADDR_ULA(&iface
->addr6
[m
].addr
.in6
)) {
276 } else if (IN6_IS_ADDR_ULA(&iface
->addr6
[m
].addr
.in6
))
279 if (iface
->addr6
[i
].preferred
> iface
->addr6
[m
].preferred
)
284 *addr
= iface
->addr6
[m
].addr
.in6
;
288 return odhcpd_get_linklocal_interface_address(iface
->ifindex
, addr
);
291 struct interface
* odhcpd_get_interface_by_index(int ifindex
)
293 struct interface
*iface
;
295 avl_for_each_element(&interfaces
, iface
, avl
) {
296 if (iface
->ifindex
== ifindex
)
303 /* Convenience function to receive and do basic validation of packets */
304 static void odhcpd_receive_packets(struct uloop_fd
*u
, _unused
unsigned int events
)
306 struct odhcpd_event
*e
= container_of(u
, struct odhcpd_event
, uloop
);
308 uint8_t data_buf
[8192], cmsg_buf
[128];
310 struct sockaddr_in6 in6
;
311 struct sockaddr_in in
;
312 struct sockaddr_ll ll
;
313 struct sockaddr_nl nl
;
318 socklen_t ret_len
= sizeof(ret
);
321 if (e
->handle_error
&& getsockopt(u
->fd
, SOL_SOCKET
, SO_ERROR
, &ret
, &ret_len
) == 0)
322 e
->handle_error(e
, ret
);
331 struct iovec iov
= {data_buf
, sizeof(data_buf
)};
332 struct msghdr msg
= {
333 .msg_name
= (void *) &addr
,
334 .msg_namelen
= sizeof(addr
),
337 .msg_control
= cmsg_buf
,
338 .msg_controllen
= sizeof(cmsg_buf
),
342 ssize_t len
= recvmsg(u
->fd
, &msg
, MSG_DONTWAIT
);
351 /* Extract destination interface */
355 struct in6_pktinfo
*pktinfo
;
356 struct in_pktinfo
*pkt4info
;
357 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
; ch
= CMSG_NXTHDR(&msg
, ch
)) {
358 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
359 ch
->cmsg_type
== IPV6_PKTINFO
) {
360 pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(ch
);
361 destiface
= pktinfo
->ipi6_ifindex
;
362 dest
= &pktinfo
->ipi6_addr
;
363 } else if (ch
->cmsg_level
== IPPROTO_IP
&&
364 ch
->cmsg_type
== IP_PKTINFO
) {
365 pkt4info
= (struct in_pktinfo
*)CMSG_DATA(ch
);
366 destiface
= pkt4info
->ipi_ifindex
;
367 dest
= &pkt4info
->ipi_addr
;
368 } else if (ch
->cmsg_level
== IPPROTO_IPV6
&&
369 ch
->cmsg_type
== IPV6_HOPLIMIT
) {
370 hlim
= (int*)CMSG_DATA(ch
);
374 /* Check hoplimit if received */
375 if (hlim
&& *hlim
!= 255)
378 /* Detect interface for packet sockets */
379 if (addr
.ll
.sll_family
== AF_PACKET
)
380 destiface
= addr
.ll
.sll_ifindex
;
382 char ipbuf
[INET6_ADDRSTRLEN
] = "kernel";
383 if (addr
.ll
.sll_family
== AF_PACKET
&&
384 len
>= (ssize_t
)sizeof(struct ip6_hdr
))
385 inet_ntop(AF_INET6
, &data_buf
[8], ipbuf
, sizeof(ipbuf
));
386 else if (addr
.in6
.sin6_family
== AF_INET6
)
387 inet_ntop(AF_INET6
, &addr
.in6
.sin6_addr
, ipbuf
, sizeof(ipbuf
));
388 else if (addr
.in
.sin_family
== AF_INET
)
389 inet_ntop(AF_INET
, &addr
.in
.sin_addr
, ipbuf
, sizeof(ipbuf
));
392 if (addr
.nl
.nl_family
== AF_NETLINK
) {
393 syslog(LOG_DEBUG
, "Received %zd Bytes from %s%%netlink", len
,
395 e
->handle_dgram(&addr
, data_buf
, len
, NULL
, dest
);
397 } else if (destiface
!= 0) {
398 struct interface
*iface
;
400 avl_for_each_element(&interfaces
, iface
, avl
) {
401 if (iface
->ifindex
!= destiface
)
404 syslog(LOG_DEBUG
, "Received %zd Bytes from %s%%%s@%s", len
,
405 ipbuf
, iface
->name
, iface
->ifname
);
407 e
->handle_dgram(&addr
, data_buf
, len
, iface
, dest
);
415 /* Register events for the multiplexer */
416 int odhcpd_register(struct odhcpd_event
*event
)
418 event
->uloop
.cb
= odhcpd_receive_packets
;
419 return uloop_fd_add(&event
->uloop
, ULOOP_READ
|
420 ((event
->handle_error
) ? ULOOP_ERROR_CB
: 0));
423 int odhcpd_deregister(struct odhcpd_event
*event
)
425 event
->uloop
.cb
= NULL
;
426 return uloop_fd_delete(&event
->uloop
);
429 void odhcpd_process(struct odhcpd_event
*event
)
431 odhcpd_receive_packets(&event
->uloop
, 0);
434 int odhcpd_urandom(void *data
, size_t len
)
436 return read(urandom_fd
, data
, len
);
440 time_t odhcpd_time(void)
443 syscall(SYS_clock_gettime
, CLOCK_MONOTONIC
, &ts
);
448 static const char hexdigits
[] = "0123456789abcdef";
449 static const int8_t hexvals
[] = {
450 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
451 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
452 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
453 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
454 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
455 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
456 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
457 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
460 ssize_t
odhcpd_unhexlify(uint8_t *dst
, size_t len
, const char *src
)
463 for (c
= 0; c
< len
&& src
[0] && src
[1]; ++c
) {
464 int8_t x
= (int8_t)*src
++;
465 int8_t y
= (int8_t)*src
++;
466 if (x
< 0 || (x
= hexvals
[x
]) < 0
467 || y
< 0 || (y
= hexvals
[y
]) < 0)
470 while (((int8_t)*src
) < 0 ||
471 (*src
&& hexvals
[(uint8_t)*src
] < 0))
479 void odhcpd_hexlify(char *dst
, const uint8_t *src
, size_t len
)
481 for (size_t i
= 0; i
< len
; ++i
) {
482 *dst
++ = hexdigits
[src
[i
] >> 4];
483 *dst
++ = hexdigits
[src
[i
] & 0x0f];
488 const char *odhcpd_print_mac(const uint8_t *mac
, const size_t len
)
492 snprintf(buf
, sizeof(buf
), "%02x", mac
[0]);
493 for (size_t i
= 1, j
= 2; i
< len
&& j
< sizeof(buf
); i
++, j
+= 3)
494 snprintf(buf
+ j
, sizeof(buf
) - j
, ":%02x", mac
[i
]);
499 int odhcpd_bmemcmp(const void *av
, const void *bv
, size_t bits
)
501 const uint8_t *a
= av
, *b
= bv
;
502 size_t bytes
= bits
/ 8;
505 int res
= memcmp(a
, b
, bytes
);
506 if (res
== 0 && bits
> 0)
507 res
= (a
[bytes
] >> (8 - bits
)) - (b
[bytes
] >> (8 - bits
));
513 void odhcpd_bmemcpy(void *av
, const void *bv
, size_t bits
)
516 const uint8_t *b
= bv
;
518 size_t bytes
= bits
/ 8;
523 uint8_t mask
= (1 << (8 - bits
)) - 1;
524 a
[bytes
] = (a
[bytes
] & mask
) | ((~mask
) & b
[bytes
]);
529 int odhcpd_netmask2bitlen(bool inet6
, void *mask
)
536 for (bits
= 0, v6
= mask
;
537 bits
< 128 && (v6
->s6_addr
[bits
/ 8] << (bits
% 8)) & 128;
540 for (bits
= 0, v4
= mask
;
541 bits
< 32 && (ntohl(v4
->s_addr
) << bits
) & 0x80000000;
547 bool odhcpd_bitlen2netmask(bool inet6
, unsigned int bits
, void *mask
)
560 for (unsigned int i
= 0; i
< sizeof(v6
->s6_addr
); i
++)
562 b
= (bits
> 8) ? 8 : bits
;
563 v6
->s6_addr
[i
] = (uint8_t)(0xFF << (8 - b
));
573 v4
->s_addr
= bits
? htonl(~((1 << (32 - bits
)) - 1)) : 0;
579 bool odhcpd_valid_hostname(const char *name
)
582 const char *c
, *label
, *label_end
;
585 for (c
= name
, label_sz
= 0, label
= name
, label_end
= name
+ strcspn(name
, ".") - 1;
586 *c
&& label_sz
<= MAX_LABEL
; c
++) {
587 if ((*c
>= '0' && *c
<= '9') ||
588 (*c
>= 'A' && *c
<= 'Z') ||
589 (*c
>= 'a' && *c
<= 'z')) {
594 if ((*c
== '_' || *c
== '-') && c
!= label
&& c
!= label_end
) {
602 label_end
= label
+ strcspn(label
, ".") - 1;
611 return (label_sz
&& label_sz
<= MAX_LABEL
? true : false);