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
);
121 // Read IPv6 MTU for interface
122 int odhcpd_get_interface_config(const char *ifname
, const char *what
)
125 const char *sysctl_pattern
= "/proc/sys/net/ipv6/conf/%s/%s";
126 snprintf(buf
, sizeof(buf
), sysctl_pattern
, ifname
, what
);
128 int fd
= open(buf
, O_RDONLY
);
129 ssize_t len
= read(fd
, buf
, sizeof(buf
) - 1);
140 // Read IPv6 MAC for interface
141 int odhcpd_get_mac(const struct interface
*iface
, uint8_t mac
[6])
144 memset(&ifr
, 0, sizeof(ifr
));
145 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
));
146 if (ioctl(ioctl_sock
, SIOCGIFHWADDR
, &ifr
) < 0)
148 memcpy(mac
, ifr
.ifr_hwaddr
.sa_data
, 6);
153 // Forwards a packet on a specific interface
154 ssize_t
odhcpd_send(int socket
, struct sockaddr_in6
*dest
,
155 struct iovec
*iov
, size_t iov_len
,
156 const struct interface
*iface
)
159 uint8_t cmsg_buf
[CMSG_SPACE(sizeof(struct in6_pktinfo
))] = {0};
160 struct msghdr msg
= {
161 .msg_name
= (void *) dest
,
162 .msg_namelen
= sizeof(*dest
),
164 .msg_iovlen
= iov_len
,
165 .msg_control
= cmsg_buf
,
166 .msg_controllen
= sizeof(cmsg_buf
),
170 // Set control data (define destination interface)
171 struct cmsghdr
*chdr
= CMSG_FIRSTHDR(&msg
);
172 chdr
->cmsg_level
= IPPROTO_IPV6
;
173 chdr
->cmsg_type
= IPV6_PKTINFO
;
174 chdr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
175 struct in6_pktinfo
*pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(chdr
);
176 pktinfo
->ipi6_ifindex
= iface
->ifindex
;
178 // Also set scope ID if link-local
179 if (IN6_IS_ADDR_LINKLOCAL(&dest
->sin6_addr
)
180 || IN6_IS_ADDR_MC_LINKLOCAL(&dest
->sin6_addr
))
181 dest
->sin6_scope_id
= iface
->ifindex
;
183 char ipbuf
[INET6_ADDRSTRLEN
];
184 inet_ntop(AF_INET6
, &dest
->sin6_addr
, ipbuf
, sizeof(ipbuf
));
186 ssize_t sent
= sendmsg(socket
, &msg
, MSG_DONTWAIT
);
188 syslog(LOG_NOTICE
, "Failed to send to %s%%%s (%s)",
189 ipbuf
, iface
->ifname
, strerror(errno
));
191 syslog(LOG_DEBUG
, "Sent %li bytes to %s%%%s",
192 (long)sent
, ipbuf
, iface
->ifname
);
197 static int odhcpd_get_linklocal_interface_address(int ifindex
, struct in6_addr
*lladdr
)
200 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, ifindex
};
201 socklen_t alen
= sizeof(addr
);
202 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
204 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
205 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
)) {
206 *lladdr
= addr
.sin6_addr
;
216 * DNS address selection criteria order :
217 * - use IPv6 address with valid lifetime if none is yet selected
218 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
219 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
220 * - use the IPv6 address with the longest preferred lifetime
222 int odhcpd_get_interface_dns_addr(const struct interface
*iface
, struct in6_addr
*addr
)
224 time_t now
= odhcpd_time();
227 for (size_t i
= 0; i
< iface
->addr6_len
; ++i
) {
228 if (iface
->addr6
[i
].valid
<= (uint32_t)now
)
236 if (iface
->addr6
[m
].preferred
>= (uint32_t)now
&&
237 iface
->addr6
[i
].preferred
< (uint32_t)now
)
240 if (IN6_IS_ADDR_ULA(&iface
->addr6
[i
].addr
.in6
)) {
241 if (!IN6_IS_ADDR_ULA(&iface
->addr6
[m
].addr
.in6
)) {
245 } else if (IN6_IS_ADDR_ULA(&iface
->addr6
[m
].addr
.in6
))
248 if (iface
->addr6
[i
].preferred
> iface
->addr6
[m
].preferred
)
253 *addr
= iface
->addr6
[m
].addr
.in6
;
257 return odhcpd_get_linklocal_interface_address(iface
->ifindex
, addr
);
260 struct interface
* odhcpd_get_interface_by_index(int ifindex
)
262 struct interface
*iface
;
263 list_for_each_entry(iface
, &interfaces
, head
)
264 if (iface
->ifindex
== ifindex
)
271 struct interface
* odhcpd_get_interface_by_name(const char *name
)
273 struct interface
*iface
;
274 list_for_each_entry(iface
, &interfaces
, head
)
275 if (!strcmp(iface
->ifname
, name
))
282 struct interface
* odhcpd_get_master_interface(void)
284 struct interface
*iface
;
285 list_for_each_entry(iface
, &interfaces
, head
)
293 // Convenience function to receive and do basic validation of packets
294 static void odhcpd_receive_packets(struct uloop_fd
*u
, _unused
unsigned int events
)
296 struct odhcpd_event
*e
= container_of(u
, struct odhcpd_event
, uloop
);
298 uint8_t data_buf
[8192], cmsg_buf
[128];
300 struct sockaddr_in6 in6
;
301 struct sockaddr_in in
;
302 struct sockaddr_ll ll
;
303 struct sockaddr_nl nl
;
308 socklen_t ret_len
= sizeof(ret
);
309 getsockopt(u
->fd
, SOL_SOCKET
, SO_ERROR
, &ret
, &ret_len
);
312 e
->handle_error(e
, ret
);
321 struct iovec iov
= {data_buf
, sizeof(data_buf
)};
322 struct msghdr msg
= {
323 .msg_name
= (void *) &addr
,
324 .msg_namelen
= sizeof(addr
),
327 .msg_control
= cmsg_buf
,
328 .msg_controllen
= sizeof(cmsg_buf
),
332 ssize_t len
= recvmsg(u
->fd
, &msg
, MSG_DONTWAIT
);
341 // Extract destination interface
345 struct in6_pktinfo
*pktinfo
;
346 struct in_pktinfo
*pkt4info
;
347 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
; ch
= CMSG_NXTHDR(&msg
, ch
)) {
348 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
349 ch
->cmsg_type
== IPV6_PKTINFO
) {
350 pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(ch
);
351 destiface
= pktinfo
->ipi6_ifindex
;
352 dest
= &pktinfo
->ipi6_addr
;
353 } else if (ch
->cmsg_level
== IPPROTO_IP
&&
354 ch
->cmsg_type
== IP_PKTINFO
) {
355 pkt4info
= (struct in_pktinfo
*)CMSG_DATA(ch
);
356 destiface
= pkt4info
->ipi_ifindex
;
357 dest
= &pkt4info
->ipi_addr
;
358 } else if (ch
->cmsg_level
== IPPROTO_IPV6
&&
359 ch
->cmsg_type
== IPV6_HOPLIMIT
) {
360 hlim
= (int*)CMSG_DATA(ch
);
364 // Check hoplimit if received
365 if (hlim
&& *hlim
!= 255)
368 // Detect interface for packet sockets
369 if (addr
.ll
.sll_family
== AF_PACKET
)
370 destiface
= addr
.ll
.sll_ifindex
;
372 struct interface
*iface
=
373 odhcpd_get_interface_by_index(destiface
);
375 if (!iface
&& addr
.nl
.nl_family
!= AF_NETLINK
)
378 char ipbuf
[INET6_ADDRSTRLEN
] = "kernel";
379 if (addr
.ll
.sll_family
== AF_PACKET
&&
380 len
>= (ssize_t
)sizeof(struct ip6_hdr
))
381 inet_ntop(AF_INET6
, &data_buf
[8], ipbuf
, sizeof(ipbuf
));
382 else if (addr
.in6
.sin6_family
== AF_INET6
)
383 inet_ntop(AF_INET6
, &addr
.in6
.sin6_addr
, ipbuf
, sizeof(ipbuf
));
384 else if (addr
.in
.sin_family
== AF_INET
)
385 inet_ntop(AF_INET
, &addr
.in
.sin_addr
, ipbuf
, sizeof(ipbuf
));
387 syslog(LOG_DEBUG
, "Received %li Bytes from %s%%%s", (long)len
,
388 ipbuf
, (iface
) ? iface
->ifname
: "netlink");
390 e
->handle_dgram(&addr
, data_buf
, len
, iface
, dest
);
394 // Register events for the multiplexer
395 int odhcpd_register(struct odhcpd_event
*event
)
397 event
->uloop
.cb
= odhcpd_receive_packets
;
398 return uloop_fd_add(&event
->uloop
, ULOOP_READ
|
399 ((event
->handle_error
) ? ULOOP_ERROR_CB
: 0));
402 int odhcpd_deregister(struct odhcpd_event
*event
)
404 event
->uloop
.cb
= NULL
;
405 return uloop_fd_delete(&event
->uloop
);
408 void odhcpd_process(struct odhcpd_event
*event
)
410 odhcpd_receive_packets(&event
->uloop
, 0);
413 int odhcpd_urandom(void *data
, size_t len
)
415 return read(urandom_fd
, data
, len
);
419 time_t odhcpd_time(void)
422 syscall(SYS_clock_gettime
, CLOCK_MONOTONIC
, &ts
);
427 static const char hexdigits
[] = "0123456789abcdef";
428 static const int8_t hexvals
[] = {
429 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
430 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
431 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
432 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
433 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
434 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -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,
439 ssize_t
odhcpd_unhexlify(uint8_t *dst
, size_t len
, const char *src
)
442 for (c
= 0; c
< len
&& src
[0] && src
[1]; ++c
) {
443 int8_t x
= (int8_t)*src
++;
444 int8_t y
= (int8_t)*src
++;
445 if (x
< 0 || (x
= hexvals
[x
]) < 0
446 || y
< 0 || (y
= hexvals
[y
]) < 0)
449 while (((int8_t)*src
) < 0 ||
450 (*src
&& hexvals
[(uint8_t)*src
] < 0))
458 void odhcpd_hexlify(char *dst
, const uint8_t *src
, size_t len
)
460 for (size_t i
= 0; i
< len
; ++i
) {
461 *dst
++ = hexdigits
[src
[i
] >> 4];
462 *dst
++ = hexdigits
[src
[i
] & 0x0f];
468 int odhcpd_bmemcmp(const void *av
, const void *bv
, size_t bits
)
470 const uint8_t *a
= av
, *b
= bv
;
471 size_t bytes
= bits
/ 8;
474 int res
= memcmp(a
, b
, bytes
);
475 if (res
== 0 && bits
> 0)
476 res
= (a
[bytes
] >> (8 - bits
)) - (b
[bytes
] >> (8 - bits
));
482 void odhcpd_bmemcpy(void *av
, const void *bv
, size_t bits
)
485 const uint8_t *b
= bv
;
487 size_t bytes
= bits
/ 8;
492 uint8_t mask
= (1 << (8 - bits
)) - 1;
493 a
[bytes
] = (a
[bytes
] & mask
) | ((~mask
) & b
[bytes
]);
498 int odhcpd_netmask2bitlen(bool inet6
, void *mask
)
505 for (bits
= 0, v6
= mask
;
506 bits
< 128 && (v6
->s6_addr
[bits
/ 8] << (bits
% 8)) & 128;
509 for (bits
= 0, v4
= mask
;
510 bits
< 32 && (ntohl(v4
->s_addr
) << bits
) & 0x80000000;
516 bool odhcpd_bitlen2netmask(bool inet6
, unsigned int bits
, void *mask
)
529 for (unsigned int i
= 0; i
< sizeof(v6
->s6_addr
); i
++)
531 b
= (bits
> 8) ? 8 : bits
;
532 v6
->s6_addr
[i
] = (uint8_t)(0xFF << (8 - b
));
542 v4
->s_addr
= bits
? htonl(~((1 << (32 - bits
)) - 1)) : 0;