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.
28 #include <arpa/inet.h>
30 #include <netinet/ip6.h>
31 #include <netpacket/packet.h>
32 #include <linux/netlink.h>
33 #include <linux/rtnetlink.h>
35 #include <sys/socket.h>
36 #include <sys/ioctl.h>
37 #include <sys/epoll.h>
38 #include <sys/types.h>
40 #include <sys/syscall.h>
42 #include <libubox/uloop.h>
47 static int ioctl_sock
;
48 static int rtnl_socket
= -1;
49 static int rtnl_seq
= 0;
50 static int urandom_fd
= -1;
53 static void sighandler(_unused
int signal
)
58 static void print_usage(const char *app
)
62 " -h, --help Print this help\n"
63 " -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
);
72 int log_level
= LOG_INFO
;
73 while ((opt
= getopt(argc
, argv
, "hl:")) != -1) {
79 log_level
= atoi(optarg
);
80 fprintf(stderr
, "Log level set to %d\n", log_level
);
84 setlogmask(LOG_UPTO(log_level
));
88 syslog(LOG_ERR
, "Must be run as root!");
92 ioctl_sock
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, 0);
94 if ((rtnl_socket
= odhcpd_open_rtnl()) < 0) {
95 syslog(LOG_ERR
, "Unable to open socket: %s", strerror(errno
));
99 if ((urandom_fd
= open("/dev/urandom", O_RDONLY
| O_CLOEXEC
)) < 0)
102 signal(SIGUSR1
, SIG_IGN
);
103 signal(SIGINT
, sighandler
);
104 signal(SIGTERM
, sighandler
);
122 int odhcpd_open_rtnl(void)
124 int sock
= socket(AF_NETLINK
, SOCK_RAW
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
126 // Connect to the kernel netlink interface
127 struct sockaddr_nl nl
= {.nl_family
= AF_NETLINK
};
128 if (connect(sock
, (struct sockaddr
*)&nl
, sizeof(nl
))) {
129 syslog(LOG_ERR
, "Failed to connect to kernel rtnetlink: %s",
138 // Read IPv6 MTU for interface
139 int odhcpd_get_interface_config(const char *ifname
, const char *what
)
142 const char *sysctl_pattern
= "/proc/sys/net/ipv6/conf/%s/%s";
143 snprintf(buf
, sizeof(buf
), sysctl_pattern
, ifname
, what
);
145 int fd
= open(buf
, O_RDONLY
);
146 ssize_t len
= read(fd
, buf
, sizeof(buf
) - 1);
157 // Read IPv6 MAC for interface
158 int odhcpd_get_mac(const struct interface
*iface
, uint8_t mac
[6])
161 memset(&ifr
, 0, sizeof(ifr
));
162 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
));
163 if (ioctl(ioctl_sock
, SIOCGIFHWADDR
, &ifr
) < 0)
165 memcpy(mac
, ifr
.ifr_hwaddr
.sa_data
, 6);
170 // Forwards a packet on a specific interface
171 ssize_t
odhcpd_send(int socket
, struct sockaddr_in6
*dest
,
172 struct iovec
*iov
, size_t iov_len
,
173 const struct interface
*iface
)
176 uint8_t cmsg_buf
[CMSG_SPACE(sizeof(struct in6_pktinfo
))] = {0};
177 struct msghdr msg
= {
178 .msg_name
= (void *) dest
,
179 .msg_namelen
= sizeof(*dest
),
181 .msg_iovlen
= iov_len
,
182 .msg_control
= cmsg_buf
,
183 .msg_controllen
= sizeof(cmsg_buf
),
187 // Set control data (define destination interface)
188 struct cmsghdr
*chdr
= CMSG_FIRSTHDR(&msg
);
189 chdr
->cmsg_level
= IPPROTO_IPV6
;
190 chdr
->cmsg_type
= IPV6_PKTINFO
;
191 chdr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
192 struct in6_pktinfo
*pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(chdr
);
193 pktinfo
->ipi6_ifindex
= iface
->ifindex
;
195 // Also set scope ID if link-local
196 if (IN6_IS_ADDR_LINKLOCAL(&dest
->sin6_addr
)
197 || IN6_IS_ADDR_MC_LINKLOCAL(&dest
->sin6_addr
))
198 dest
->sin6_scope_id
= iface
->ifindex
;
200 char ipbuf
[INET6_ADDRSTRLEN
];
201 inet_ntop(AF_INET6
, &dest
->sin6_addr
, ipbuf
, sizeof(ipbuf
));
203 ssize_t sent
= sendmsg(socket
, &msg
, MSG_DONTWAIT
);
205 syslog(LOG_NOTICE
, "Failed to send to %s%%%s (%s)",
206 ipbuf
, iface
->ifname
, strerror(errno
));
208 syslog(LOG_DEBUG
, "Sent %li bytes to %s%%%s",
209 (long)sent
, ipbuf
, iface
->ifname
);
214 // Detect an IPV6-address currently assigned to the given interface
215 ssize_t
odhcpd_get_interface_addresses(int ifindex
,
216 struct odhcpd_ipaddr
*addrs
, size_t cnt
)
220 struct ifaddrmsg ifa
;
221 } req
= {{sizeof(req
), RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
,
222 ++rtnl_seq
, 0}, {AF_INET6
, 0, 0, 0, ifindex
}};
223 if (send(rtnl_socket
, &req
, sizeof(req
), 0) < (ssize_t
)sizeof(req
)) {
224 syslog(LOG_WARNING
, "Request failed to dump IPv6 addresses (%s)", strerror(errno
));
229 ssize_t len
= 0, ret
= 0;
231 for (struct nlmsghdr
*nhm
= NULL
; ; nhm
= NLMSG_NEXT(nhm
, len
)) {
232 while (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
233 len
= recv(rtnl_socket
, buf
, sizeof(buf
), 0);
234 nhm
= (struct nlmsghdr
*)buf
;
235 if (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
239 syslog(LOG_WARNING
, "Failed to receive IPv6 address rtnetlink message (%s)", strerror(errno
));
245 switch (nhm
->nlmsg_type
) {
247 // Skip address but keep clearing socket buffer
248 if (ret
>= (ssize_t
)cnt
)
251 struct ifaddrmsg
*ifa
= NLMSG_DATA(nhm
);
252 if (ifa
->ifa_scope
!= RT_SCOPE_UNIVERSE
||
253 (ifindex
&& ifa
->ifa_index
!= (unsigned)ifindex
))
256 struct rtattr
*rta
= (struct rtattr
*)&ifa
[1];
257 size_t alen
= NLMSG_PAYLOAD(nhm
, sizeof(*ifa
));
258 memset(&addrs
[ret
], 0, sizeof(addrs
[ret
]));
259 addrs
[ret
].prefix
= ifa
->ifa_prefixlen
;
261 while (RTA_OK(rta
, alen
)) {
262 if (rta
->rta_type
== IFA_ADDRESS
) {
263 memcpy(&addrs
[ret
].addr
, RTA_DATA(rta
),
264 sizeof(struct in6_addr
));
265 } else if (rta
->rta_type
== IFA_CACHEINFO
) {
266 struct ifa_cacheinfo
*ifc
= RTA_DATA(rta
);
267 addrs
[ret
].preferred
= ifc
->ifa_prefered
;
268 addrs
[ret
].valid
= ifc
->ifa_valid
;
271 rta
= RTA_NEXT(rta
, alen
);
274 if (ifa
->ifa_flags
& IFA_F_DEPRECATED
)
275 addrs
[ret
].preferred
= 0;
283 syslog(LOG_WARNING
, "Unexpected rtnetlink message (%d) in response to IPv6 address dump", nhm
->nlmsg_type
);
293 int odhcpd_get_linklocal_interface_address(int ifindex
, struct in6_addr
*lladdr
)
296 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, ifindex
};
297 socklen_t alen
= sizeof(addr
);
298 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
300 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
301 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
)) {
302 *lladdr
= addr
.sin6_addr
;
311 void odhcpd_setup_route(const struct in6_addr
*addr
, int prefixlen
,
312 const struct interface
*iface
, const struct in6_addr
*gw
,
313 int metric
, bool add
)
318 struct rtattr rta_dst
;
319 struct in6_addr dst_addr
;
320 struct rtattr rta_oif
;
322 struct rtattr rta_table
;
324 struct rtattr rta_prio
;
326 struct rtattr rta_gw
;
329 {sizeof(req
), 0, NLM_F_REQUEST
, ++rtnl_seq
, 0},
330 {AF_INET6
, prefixlen
, 0, 0, 0, 0, 0, 0, 0},
331 {sizeof(struct rtattr
) + sizeof(struct in6_addr
), RTA_DST
},
333 {sizeof(struct rtattr
) + sizeof(uint32_t), RTA_OIF
},
335 {sizeof(struct rtattr
) + sizeof(uint32_t), RTA_TABLE
},
337 {sizeof(struct rtattr
) + sizeof(uint32_t), RTA_PRIORITY
},
339 {sizeof(struct rtattr
) + sizeof(struct in6_addr
), RTA_GATEWAY
},
347 req
.nh
.nlmsg_type
= RTM_NEWROUTE
;
348 req
.nh
.nlmsg_flags
|= (NLM_F_CREATE
| NLM_F_REPLACE
);
349 req
.rtm
.rtm_protocol
= RTPROT_STATIC
;
350 req
.rtm
.rtm_scope
= (gw
) ? RT_SCOPE_UNIVERSE
: RT_SCOPE_LINK
;
351 req
.rtm
.rtm_type
= RTN_UNICAST
;
353 req
.nh
.nlmsg_type
= RTM_DELROUTE
;
354 req
.rtm
.rtm_scope
= RT_SCOPE_NOWHERE
;
357 req
.nh
.nlmsg_len
= (gw
) ? sizeof(req
) : offsetof(struct req
, rta_gw
);
358 send(rtnl_socket
, &req
, req
.nh
.nlmsg_len
, MSG_DONTWAIT
);
361 struct interface
* odhcpd_get_interface_by_index(int ifindex
)
363 struct interface
*iface
;
364 list_for_each_entry(iface
, &interfaces
, head
)
365 if (iface
->ifindex
== ifindex
)
372 struct interface
* odhcpd_get_interface_by_name(const char *name
)
374 struct interface
*iface
;
375 list_for_each_entry(iface
, &interfaces
, head
)
376 if (!strcmp(iface
->ifname
, name
))
383 struct interface
* odhcpd_get_master_interface(void)
385 struct interface
*iface
;
386 list_for_each_entry(iface
, &interfaces
, head
)
394 // Convenience function to receive and do basic validation of packets
395 static void odhcpd_receive_packets(struct uloop_fd
*u
, _unused
unsigned int events
)
397 struct odhcpd_event
*e
= container_of(u
, struct odhcpd_event
, uloop
);
399 uint8_t data_buf
[RELAYD_BUFFER_SIZE
], cmsg_buf
[128];
401 struct sockaddr_in6 in6
;
402 struct sockaddr_in in
;
403 struct sockaddr_ll ll
;
404 struct sockaddr_nl nl
;
409 socklen_t ret_len
= sizeof(ret
);
410 getsockopt(u
->fd
, SOL_SOCKET
, SO_ERROR
, &ret
, &ret_len
);
413 e
->handle_error(ret
);
417 struct iovec iov
= {data_buf
, sizeof(data_buf
)};
418 struct msghdr msg
= {
419 .msg_name
= (void *) &addr
,
420 .msg_namelen
= sizeof(addr
),
423 .msg_control
= cmsg_buf
,
424 .msg_controllen
= sizeof(cmsg_buf
),
428 ssize_t len
= recvmsg(u
->fd
, &msg
, MSG_DONTWAIT
);
437 // Extract destination interface
441 struct in6_pktinfo
*pktinfo
;
442 struct in_pktinfo
*pkt4info
;
443 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
; ch
= CMSG_NXTHDR(&msg
, ch
)) {
444 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
445 ch
->cmsg_type
== IPV6_PKTINFO
) {
446 pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(ch
);
447 destiface
= pktinfo
->ipi6_ifindex
;
448 dest
= &pktinfo
->ipi6_addr
;
449 } else if (ch
->cmsg_level
== IPPROTO_IP
&&
450 ch
->cmsg_type
== IP_PKTINFO
) {
451 pkt4info
= (struct in_pktinfo
*)CMSG_DATA(ch
);
452 destiface
= pkt4info
->ipi_ifindex
;
453 dest
= &pkt4info
->ipi_addr
;
454 } else if (ch
->cmsg_level
== IPPROTO_IPV6
&&
455 ch
->cmsg_type
== IPV6_HOPLIMIT
) {
456 hlim
= (int*)CMSG_DATA(ch
);
460 // Check hoplimit if received
461 if (hlim
&& *hlim
!= 255)
464 // Detect interface for packet sockets
465 if (addr
.ll
.sll_family
== AF_PACKET
)
466 destiface
= addr
.ll
.sll_ifindex
;
468 struct interface
*iface
=
469 odhcpd_get_interface_by_index(destiface
);
471 if (!iface
&& addr
.nl
.nl_family
!= AF_NETLINK
)
474 char ipbuf
[INET6_ADDRSTRLEN
] = "kernel";
475 if (addr
.ll
.sll_family
== AF_PACKET
&&
476 len
>= (ssize_t
)sizeof(struct ip6_hdr
))
477 inet_ntop(AF_INET6
, &data_buf
[8], ipbuf
, sizeof(ipbuf
));
478 else if (addr
.in6
.sin6_family
== AF_INET6
)
479 inet_ntop(AF_INET6
, &addr
.in6
.sin6_addr
, ipbuf
, sizeof(ipbuf
));
480 else if (addr
.in
.sin_family
== AF_INET
)
481 inet_ntop(AF_INET
, &addr
.in
.sin_addr
, ipbuf
, sizeof(ipbuf
));
483 syslog(LOG_DEBUG
, "Received %li Bytes from %s%%%s", (long)len
,
484 ipbuf
, (iface
) ? iface
->ifname
: "netlink");
486 e
->handle_dgram(&addr
, data_buf
, len
, iface
, dest
);
490 // Register events for the multiplexer
491 int odhcpd_register(struct odhcpd_event
*event
)
493 event
->uloop
.cb
= odhcpd_receive_packets
;
494 return uloop_fd_add(&event
->uloop
, ULOOP_READ
|
495 ((event
->handle_error
) ? ULOOP_ERROR_CB
: 0));
498 void odhcpd_process(struct odhcpd_event
*event
)
500 odhcpd_receive_packets(&event
->uloop
, 0);
503 int odhcpd_urandom(void *data
, size_t len
)
505 return read(urandom_fd
, data
, len
);
509 time_t odhcpd_time(void)
512 syscall(SYS_clock_gettime
, CLOCK_MONOTONIC
, &ts
);
517 static const char hexdigits
[] = "0123456789abcdef";
518 static const int8_t hexvals
[] = {
519 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
520 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
521 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
522 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
523 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
524 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
525 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
526 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
529 ssize_t
odhcpd_unhexlify(uint8_t *dst
, size_t len
, const char *src
)
532 for (c
= 0; c
< len
&& src
[0] && src
[1]; ++c
) {
533 int8_t x
= (int8_t)*src
++;
534 int8_t y
= (int8_t)*src
++;
535 if (x
< 0 || (x
= hexvals
[x
]) < 0
536 || y
< 0 || (y
= hexvals
[y
]) < 0)
539 while (((int8_t)*src
) < 0 ||
540 (*src
&& hexvals
[(uint8_t)*src
] < 0))
548 void odhcpd_hexlify(char *dst
, const uint8_t *src
, size_t len
)
550 for (size_t i
= 0; i
< len
; ++i
) {
551 *dst
++ = hexdigits
[src
[i
] >> 4];
552 *dst
++ = hexdigits
[src
[i
] & 0x0f];
558 int odhcpd_bmemcmp(const void *av
, const void *bv
, size_t bits
)
560 const uint8_t *a
= av
, *b
= bv
;
561 size_t bytes
= bits
/ 8;
564 int res
= memcmp(a
, b
, bytes
);
565 if (res
== 0 && bits
> 0)
566 res
= (a
[bytes
] >> (8 - bits
)) - (b
[bytes
] >> (8 - bits
));
572 void odhcpd_bmemcpy(void *av
, const void *bv
, size_t bits
)
575 const uint8_t *b
= bv
;
577 size_t bytes
= bits
/ 8;
582 uint8_t mask
= (1 << (8 - bits
)) - 1;
583 a
[bytes
] = (a
[bytes
] & mask
) | ((~mask
) & b
[bytes
]);