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
)
57 static void print_usage(const char *app
)
61 " -h, --help Print this help\n"
62 " -l level Specify log level 0..7 (default %d)\n",
68 int main(int argc
, char **argv
)
70 openlog("odhcpd", LOG_PERROR
| LOG_PID
, LOG_DAEMON
);
73 while ((opt
= getopt(argc
, argv
, "hl:")) != -1) {
79 config
.log_level
= (atoi(optarg
) & LOG_PRIMASK
);
80 fprintf(stderr
, "Log level set to %d\n", config
.log_level
);
84 setlogmask(LOG_UPTO(config
.log_level
));
88 syslog(LOG_ERR
, "Must be run as root!");
92 ioctl_sock
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, 0);
94 if ((urandom_fd
= open("/dev/urandom", O_RDONLY
| O_CLOEXEC
)) < 0)
97 signal(SIGUSR1
, SIG_IGN
);
98 signal(SIGINT
, sighandler
);
99 signal(SIGTERM
, sighandler
);
113 #ifdef DHCPV4_SUPPORT
123 // Read IPv6 MTU for interface
124 int odhcpd_get_interface_config(const char *ifname
, const char *what
)
127 const char *sysctl_pattern
= "/proc/sys/net/ipv6/conf/%s/%s";
128 snprintf(buf
, sizeof(buf
), sysctl_pattern
, ifname
, what
);
130 int fd
= open(buf
, O_RDONLY
);
131 ssize_t len
= read(fd
, buf
, sizeof(buf
) - 1);
142 // Read IPv6 MAC for interface
143 int odhcpd_get_mac(const struct interface
*iface
, uint8_t mac
[6])
146 memset(&ifr
, 0, sizeof(ifr
));
147 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
));
148 if (ioctl(ioctl_sock
, SIOCGIFHWADDR
, &ifr
) < 0)
150 memcpy(mac
, ifr
.ifr_hwaddr
.sa_data
, 6);
155 // Forwards a packet on a specific interface
156 ssize_t
odhcpd_send(int socket
, struct sockaddr_in6
*dest
,
157 struct iovec
*iov
, size_t iov_len
,
158 const struct interface
*iface
)
161 uint8_t cmsg_buf
[CMSG_SPACE(sizeof(struct in6_pktinfo
))] = {0};
162 struct msghdr msg
= {
163 .msg_name
= (void *) dest
,
164 .msg_namelen
= sizeof(*dest
),
166 .msg_iovlen
= iov_len
,
167 .msg_control
= cmsg_buf
,
168 .msg_controllen
= sizeof(cmsg_buf
),
172 // Set control data (define destination interface)
173 struct cmsghdr
*chdr
= CMSG_FIRSTHDR(&msg
);
174 chdr
->cmsg_level
= IPPROTO_IPV6
;
175 chdr
->cmsg_type
= IPV6_PKTINFO
;
176 chdr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
177 struct in6_pktinfo
*pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(chdr
);
178 pktinfo
->ipi6_ifindex
= iface
->ifindex
;
180 // Also set scope ID if link-local
181 if (IN6_IS_ADDR_LINKLOCAL(&dest
->sin6_addr
)
182 || IN6_IS_ADDR_MC_LINKLOCAL(&dest
->sin6_addr
))
183 dest
->sin6_scope_id
= iface
->ifindex
;
185 char ipbuf
[INET6_ADDRSTRLEN
];
186 inet_ntop(AF_INET6
, &dest
->sin6_addr
, ipbuf
, sizeof(ipbuf
));
188 ssize_t sent
= sendmsg(socket
, &msg
, MSG_DONTWAIT
);
190 syslog(LOG_NOTICE
, "Failed to send to %s%%%s (%s)",
191 ipbuf
, iface
->ifname
, strerror(errno
));
193 syslog(LOG_DEBUG
, "Sent %li bytes to %s%%%s",
194 (long)sent
, ipbuf
, iface
->ifname
);
199 static int odhcpd_get_linklocal_interface_address(int ifindex
, struct in6_addr
*lladdr
)
202 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, ifindex
};
203 socklen_t alen
= sizeof(addr
);
204 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
206 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
207 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
)) {
208 *lladdr
= addr
.sin6_addr
;
218 * DNS address selection criteria order :
219 * - use IPv6 address with valid lifetime if none is yet selected
220 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
221 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
222 * - use the IPv6 address with the longest preferred lifetime
224 int odhcpd_get_interface_dns_addr(const struct interface
*iface
, struct in6_addr
*addr
)
226 time_t now
= odhcpd_time();
229 for (size_t i
= 0; i
< iface
->addr6_len
; ++i
) {
230 if (iface
->addr6
[i
].valid
<= (uint32_t)now
)
238 if (iface
->addr6
[m
].preferred
>= (uint32_t)now
&&
239 iface
->addr6
[i
].preferred
< (uint32_t)now
)
242 if (IN6_IS_ADDR_ULA(&iface
->addr6
[i
].addr
.in6
)) {
243 if (!IN6_IS_ADDR_ULA(&iface
->addr6
[m
].addr
.in6
)) {
247 } else if (IN6_IS_ADDR_ULA(&iface
->addr6
[m
].addr
.in6
))
250 if (iface
->addr6
[i
].preferred
> iface
->addr6
[m
].preferred
)
255 *addr
= iface
->addr6
[m
].addr
.in6
;
259 return odhcpd_get_linklocal_interface_address(iface
->ifindex
, addr
);
262 struct interface
* odhcpd_get_interface_by_index(int ifindex
)
264 struct interface
*iface
;
265 list_for_each_entry(iface
, &interfaces
, head
)
266 if (iface
->ifindex
== ifindex
)
273 struct interface
* odhcpd_get_interface_by_name(const char *name
)
275 struct interface
*iface
;
276 list_for_each_entry(iface
, &interfaces
, head
)
277 if (!strcmp(iface
->ifname
, name
))
284 struct interface
* odhcpd_get_master_interface(void)
286 struct interface
*iface
;
287 list_for_each_entry(iface
, &interfaces
, head
)
295 // Convenience function to receive and do basic validation of packets
296 static void odhcpd_receive_packets(struct uloop_fd
*u
, _unused
unsigned int events
)
298 struct odhcpd_event
*e
= container_of(u
, struct odhcpd_event
, uloop
);
300 uint8_t data_buf
[8192], cmsg_buf
[128];
302 struct sockaddr_in6 in6
;
303 struct sockaddr_in in
;
304 struct sockaddr_ll ll
;
305 struct sockaddr_nl nl
;
310 socklen_t ret_len
= sizeof(ret
);
311 getsockopt(u
->fd
, SOL_SOCKET
, SO_ERROR
, &ret
, &ret_len
);
314 e
->handle_error(e
, ret
);
323 struct iovec iov
= {data_buf
, sizeof(data_buf
)};
324 struct msghdr msg
= {
325 .msg_name
= (void *) &addr
,
326 .msg_namelen
= sizeof(addr
),
329 .msg_control
= cmsg_buf
,
330 .msg_controllen
= sizeof(cmsg_buf
),
334 ssize_t len
= recvmsg(u
->fd
, &msg
, MSG_DONTWAIT
);
343 // Extract destination interface
347 struct in6_pktinfo
*pktinfo
;
348 struct in_pktinfo
*pkt4info
;
349 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
; ch
= CMSG_NXTHDR(&msg
, ch
)) {
350 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
351 ch
->cmsg_type
== IPV6_PKTINFO
) {
352 pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(ch
);
353 destiface
= pktinfo
->ipi6_ifindex
;
354 dest
= &pktinfo
->ipi6_addr
;
355 } else if (ch
->cmsg_level
== IPPROTO_IP
&&
356 ch
->cmsg_type
== IP_PKTINFO
) {
357 pkt4info
= (struct in_pktinfo
*)CMSG_DATA(ch
);
358 destiface
= pkt4info
->ipi_ifindex
;
359 dest
= &pkt4info
->ipi_addr
;
360 } else if (ch
->cmsg_level
== IPPROTO_IPV6
&&
361 ch
->cmsg_type
== IPV6_HOPLIMIT
) {
362 hlim
= (int*)CMSG_DATA(ch
);
366 // Check hoplimit if received
367 if (hlim
&& *hlim
!= 255)
370 // Detect interface for packet sockets
371 if (addr
.ll
.sll_family
== AF_PACKET
)
372 destiface
= addr
.ll
.sll_ifindex
;
374 struct interface
*iface
=
375 odhcpd_get_interface_by_index(destiface
);
377 if (!iface
&& addr
.nl
.nl_family
!= AF_NETLINK
)
380 char ipbuf
[INET6_ADDRSTRLEN
] = "kernel";
381 if (addr
.ll
.sll_family
== AF_PACKET
&&
382 len
>= (ssize_t
)sizeof(struct ip6_hdr
))
383 inet_ntop(AF_INET6
, &data_buf
[8], ipbuf
, sizeof(ipbuf
));
384 else if (addr
.in6
.sin6_family
== AF_INET6
)
385 inet_ntop(AF_INET6
, &addr
.in6
.sin6_addr
, ipbuf
, sizeof(ipbuf
));
386 else if (addr
.in
.sin_family
== AF_INET
)
387 inet_ntop(AF_INET
, &addr
.in
.sin_addr
, ipbuf
, sizeof(ipbuf
));
389 syslog(LOG_DEBUG
, "Received %li Bytes from %s%%%s", (long)len
,
390 ipbuf
, (iface
) ? iface
->ifname
: "netlink");
392 e
->handle_dgram(&addr
, data_buf
, len
, iface
, dest
);
396 // Register events for the multiplexer
397 int odhcpd_register(struct odhcpd_event
*event
)
399 event
->uloop
.cb
= odhcpd_receive_packets
;
400 return uloop_fd_add(&event
->uloop
, ULOOP_READ
|
401 ((event
->handle_error
) ? ULOOP_ERROR_CB
: 0));
404 int odhcpd_deregister(struct odhcpd_event
*event
)
406 event
->uloop
.cb
= NULL
;
407 return uloop_fd_delete(&event
->uloop
);
410 void odhcpd_process(struct odhcpd_event
*event
)
412 odhcpd_receive_packets(&event
->uloop
, 0);
415 int odhcpd_urandom(void *data
, size_t len
)
417 return read(urandom_fd
, data
, len
);
421 time_t odhcpd_time(void)
424 syscall(SYS_clock_gettime
, CLOCK_MONOTONIC
, &ts
);
429 static const char hexdigits
[] = "0123456789abcdef";
430 static const int8_t hexvals
[] = {
431 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
432 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
433 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
434 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
435 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
436 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
437 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
438 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
441 ssize_t
odhcpd_unhexlify(uint8_t *dst
, size_t len
, const char *src
)
444 for (c
= 0; c
< len
&& src
[0] && src
[1]; ++c
) {
445 int8_t x
= (int8_t)*src
++;
446 int8_t y
= (int8_t)*src
++;
447 if (x
< 0 || (x
= hexvals
[x
]) < 0
448 || y
< 0 || (y
= hexvals
[y
]) < 0)
451 while (((int8_t)*src
) < 0 ||
452 (*src
&& hexvals
[(uint8_t)*src
] < 0))
460 void odhcpd_hexlify(char *dst
, const uint8_t *src
, size_t len
)
462 for (size_t i
= 0; i
< len
; ++i
) {
463 *dst
++ = hexdigits
[src
[i
] >> 4];
464 *dst
++ = hexdigits
[src
[i
] & 0x0f];
470 int odhcpd_bmemcmp(const void *av
, const void *bv
, size_t bits
)
472 const uint8_t *a
= av
, *b
= bv
;
473 size_t bytes
= bits
/ 8;
476 int res
= memcmp(a
, b
, bytes
);
477 if (res
== 0 && bits
> 0)
478 res
= (a
[bytes
] >> (8 - bits
)) - (b
[bytes
] >> (8 - bits
));
484 void odhcpd_bmemcpy(void *av
, const void *bv
, size_t bits
)
487 const uint8_t *b
= bv
;
489 size_t bytes
= bits
/ 8;
494 uint8_t mask
= (1 << (8 - bits
)) - 1;
495 a
[bytes
] = (a
[bytes
] & mask
) | ((~mask
) & b
[bytes
]);
500 int odhcpd_netmask2bitlen(bool inet6
, void *mask
)
507 for (bits
= 0, v6
= mask
;
508 bits
< 128 && (v6
->s6_addr
[bits
/ 8] << (bits
% 8)) & 128;
511 for (bits
= 0, v4
= mask
;
512 bits
< 32 && (ntohl(v4
->s_addr
) << bits
) & 0x80000000;
518 bool odhcpd_bitlen2netmask(bool inet6
, unsigned int bits
, void *mask
)
531 for (unsigned int i
= 0; i
< sizeof(v6
->s6_addr
); i
++)
533 b
= (bits
> 8) ? 8 : bits
;
534 v6
->s6_addr
[i
] = (uint8_t)(0xFF << (8 - b
));
544 v4
->s_addr
= bits
? htonl(~((1 << (32 - bits
)) - 1)) : 0;