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/rtnetlink.h>
34 #include <sys/socket.h>
35 #include <sys/ioctl.h>
36 #include <sys/epoll.h>
37 #include <sys/types.h>
39 #include <sys/syscall.h>
41 #include <libubox/uloop.h>
46 static int ioctl_sock
;
47 static int rtnl_socket
= -1;
48 static int rtnl_seq
= 0;
49 static int urandom_fd
= -1;
52 static void sighandler(_unused
int signal
)
60 openlog("odhcpd", LOG_PERROR
| LOG_PID
, LOG_DAEMON
);
61 setlogmask(LOG_UPTO(LOG_WARNING
));
65 syslog(LOG_ERR
, "Must be run as root!");
69 ioctl_sock
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, 0);
71 if ((rtnl_socket
= odhcpd_open_rtnl()) < 0) {
72 syslog(LOG_ERR
, "Unable to open socket: %s", strerror(errno
));
76 if ((urandom_fd
= open("/dev/urandom", O_RDONLY
| O_CLOEXEC
)) < 0)
79 signal(SIGUSR1
, SIG_IGN
);
80 signal(SIGINT
, sighandler
);
81 signal(SIGTERM
, sighandler
);
99 int odhcpd_open_rtnl(void)
101 int sock
= socket(AF_NETLINK
, SOCK_RAW
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
103 // Connect to the kernel netlink interface
104 struct sockaddr_nl nl
= {.nl_family
= AF_NETLINK
};
105 if (connect(sock
, (struct sockaddr
*)&nl
, sizeof(nl
))) {
106 syslog(LOG_ERR
, "Failed to connect to kernel rtnetlink: %s",
115 // Read IPv6 MTU for interface
116 int odhcpd_get_interface_config(const char *ifname
, const char *what
)
119 const char *sysctl_pattern
= "/proc/sys/net/ipv6/conf/%s/%s";
120 snprintf(buf
, sizeof(buf
), sysctl_pattern
, ifname
, what
);
122 int fd
= open(buf
, O_RDONLY
);
123 ssize_t len
= read(fd
, buf
, sizeof(buf
) - 1);
134 // Read IPv6 MAC for interface
135 int odhcpd_get_mac(const struct interface
*iface
, uint8_t mac
[6])
138 memset(&ifr
, 0, sizeof(ifr
));
139 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
));
140 if (ioctl(ioctl_sock
, SIOCGIFHWADDR
, &ifr
) < 0)
142 memcpy(mac
, ifr
.ifr_hwaddr
.sa_data
, 6);
147 // Forwards a packet on a specific interface
148 ssize_t
odhcpd_send(int socket
, struct sockaddr_in6
*dest
,
149 struct iovec
*iov
, size_t iov_len
,
150 const struct interface
*iface
)
153 uint8_t cmsg_buf
[CMSG_SPACE(sizeof(struct in6_pktinfo
))] = {0};
154 struct msghdr msg
= {
155 .msg_name
= (void *) dest
,
156 .msg_namelen
= sizeof(*dest
),
158 .msg_iovlen
= iov_len
,
159 .msg_control
= cmsg_buf
,
160 .msg_controllen
= sizeof(cmsg_buf
),
164 // Set control data (define destination interface)
165 struct cmsghdr
*chdr
= CMSG_FIRSTHDR(&msg
);
166 chdr
->cmsg_level
= IPPROTO_IPV6
;
167 chdr
->cmsg_type
= IPV6_PKTINFO
;
168 chdr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
169 struct in6_pktinfo
*pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(chdr
);
170 pktinfo
->ipi6_ifindex
= iface
->ifindex
;
172 // Also set scope ID if link-local
173 if (IN6_IS_ADDR_LINKLOCAL(&dest
->sin6_addr
)
174 || IN6_IS_ADDR_MC_LINKLOCAL(&dest
->sin6_addr
))
175 dest
->sin6_scope_id
= iface
->ifindex
;
177 // IPV6_PKTINFO doesn't really work for IPv6-raw sockets (bug?)
178 if (dest
->sin6_port
== 0) {
179 msg
.msg_control
= NULL
;
180 msg
.msg_controllen
= 0;
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 int odhcpd_iterate_interface_neighbors(const struct interface
*iface
,
198 void(*cb_neigh
)(const struct in6_addr
*addr
,
199 const struct interface
*iface
, void *data
), void *data
)
204 } req
= {{sizeof(req
), RTM_GETNEIGH
, NLM_F_REQUEST
| NLM_F_DUMP
,
205 ++rtnl_seq
, 0}, {AF_INET6
, 0, 0, iface
->ifindex
, 0, 0, 0}};
207 if (send(rtnl_socket
, &req
, sizeof(req
), 0) < (ssize_t
)sizeof(req
))
213 for (struct nlmsghdr
*nhm
= NULL
; ; nhm
= NLMSG_NEXT(nhm
, len
)) {
214 while (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
215 len
= recv(rtnl_socket
, buf
, sizeof(buf
), 0);
216 nhm
= (struct nlmsghdr
*)buf
;
217 if (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
225 if (nhm
->nlmsg_type
!= RTM_NEWNEIGH
)
228 struct ndmsg
*ndm
= NLMSG_DATA(nhm
);
229 if (ndm
->ndm_ifindex
!= iface
->ifindex
||
230 (ndm
->ndm_state
& NUD_FAILED
))
233 struct rtattr
*rta
= (struct rtattr
*)&ndm
[1];
234 size_t alen
= NLMSG_PAYLOAD(nhm
, sizeof(*ndm
));
236 while (RTA_OK(rta
, alen
)) {
237 if (rta
->rta_type
== NDA_DST
) {
239 cb_neigh(NULL
, iface
, data
);
242 rta
= RTA_NEXT(rta
, alen
);
252 // Detect an IPV6-address currently assigned to the given interface
253 ssize_t
odhcpd_get_interface_addresses(int ifindex
,
254 struct odhcpd_ipaddr
*addrs
, size_t cnt
)
258 struct ifaddrmsg ifa
;
259 } req
= {{sizeof(req
), RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
,
260 ++rtnl_seq
, 0}, {AF_INET6
, 0, 0, 0, ifindex
}};
261 if (send(rtnl_socket
, &req
, sizeof(req
), 0) < (ssize_t
)sizeof(req
))
265 ssize_t len
= 0, ret
= 0;
267 for (struct nlmsghdr
*nhm
= NULL
; ; nhm
= NLMSG_NEXT(nhm
, len
)) {
268 while (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
269 len
= recv(rtnl_socket
, buf
, sizeof(buf
), 0);
270 nhm
= (struct nlmsghdr
*)buf
;
271 if (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
279 if (nhm
->nlmsg_type
!= RTM_NEWADDR
)
282 // Skip address but keep clearing socket buffer
283 if (ret
>= (ssize_t
)cnt
)
286 struct ifaddrmsg
*ifa
= NLMSG_DATA(nhm
);
287 if (ifa
->ifa_scope
!= RT_SCOPE_UNIVERSE
||
288 (ifindex
&& ifa
->ifa_index
!= (unsigned)ifindex
))
291 struct rtattr
*rta
= (struct rtattr
*)&ifa
[1];
292 size_t alen
= NLMSG_PAYLOAD(nhm
, sizeof(*ifa
));
293 memset(&addrs
[ret
], 0, sizeof(addrs
[ret
]));
294 addrs
[ret
].prefix
= ifa
->ifa_prefixlen
;
296 while (RTA_OK(rta
, alen
)) {
297 if (rta
->rta_type
== IFA_ADDRESS
) {
298 memcpy(&addrs
[ret
].addr
, RTA_DATA(rta
),
299 sizeof(struct in6_addr
));
300 } else if (rta
->rta_type
== IFA_CACHEINFO
) {
301 struct ifa_cacheinfo
*ifc
= RTA_DATA(rta
);
302 addrs
[ret
].preferred
= ifc
->ifa_prefered
;
303 addrs
[ret
].valid
= ifc
->ifa_valid
;
306 rta
= RTA_NEXT(rta
, alen
);
309 if (ifa
->ifa_flags
& IFA_F_DEPRECATED
)
310 addrs
[ret
].preferred
= 0;
318 int odhcpd_get_preferred_interface_address(int ifindex
, struct in6_addr
*addr
)
320 struct odhcpd_ipaddr ipaddrs
[8];
321 ssize_t ip_cnt
= odhcpd_get_interface_addresses(ifindex
, ipaddrs
, ARRAY_SIZE(ipaddrs
));
322 uint32_t preferred
= 0;
325 for (ssize_t i
= 0; i
< ip_cnt
; i
++) {
326 struct odhcpd_ipaddr
*ipaddr
= &ipaddrs
[i
];
328 if (ipaddr
->preferred
> preferred
|| !preferred
) {
329 preferred
= ipaddr
->preferred
;
330 *addr
= ipaddr
->addr
;
338 struct interface
* odhcpd_get_interface_by_index(int ifindex
)
340 struct interface
*iface
;
341 list_for_each_entry(iface
, &interfaces
, head
)
342 if (iface
->ifindex
== ifindex
)
349 struct interface
* odhcpd_get_interface_by_name(const char *name
)
351 struct interface
*iface
;
352 list_for_each_entry(iface
, &interfaces
, head
)
353 if (!strcmp(iface
->ifname
, name
))
360 struct interface
* odhcpd_get_master_interface(void)
362 struct interface
*iface
;
363 list_for_each_entry(iface
, &interfaces
, head
)
371 // Convenience function to receive and do basic validation of packets
372 static void odhcpd_receive_packets(struct uloop_fd
*u
, _unused
unsigned int events
)
374 struct odhcpd_event
*e
= container_of(u
, struct odhcpd_event
, uloop
);
376 uint8_t data_buf
[RELAYD_BUFFER_SIZE
], cmsg_buf
[128];
378 struct sockaddr_in6 in6
;
379 struct sockaddr_in in
;
380 struct sockaddr_ll ll
;
381 struct sockaddr_nl nl
;
385 struct iovec iov
= {data_buf
, sizeof(data_buf
)};
386 struct msghdr msg
= {
387 .msg_name
= (void *) &addr
,
388 .msg_namelen
= sizeof(addr
),
391 .msg_control
= cmsg_buf
,
392 .msg_controllen
= sizeof(cmsg_buf
),
396 ssize_t len
= recvmsg(u
->fd
, &msg
, MSG_DONTWAIT
);
405 // Extract destination interface
409 struct in6_pktinfo
*pktinfo
;
410 struct in_pktinfo
*pkt4info
;
411 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
; ch
= CMSG_NXTHDR(&msg
, ch
)) {
412 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
413 ch
->cmsg_type
== IPV6_PKTINFO
) {
414 pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(ch
);
415 destiface
= pktinfo
->ipi6_ifindex
;
416 dest
= &pktinfo
->ipi6_addr
;
417 } else if (ch
->cmsg_level
== IPPROTO_IP
&&
418 ch
->cmsg_type
== IP_PKTINFO
) {
419 pkt4info
= (struct in_pktinfo
*)CMSG_DATA(ch
);
420 destiface
= pkt4info
->ipi_ifindex
;
421 dest
= &pkt4info
->ipi_addr
;
422 } else if (ch
->cmsg_level
== IPPROTO_IPV6
&&
423 ch
->cmsg_type
== IPV6_HOPLIMIT
) {
424 hlim
= (int*)CMSG_DATA(ch
);
428 // Check hoplimit if received
429 if (hlim
&& *hlim
!= 255)
432 // Detect interface for packet sockets
433 if (addr
.ll
.sll_family
== AF_PACKET
)
434 destiface
= addr
.ll
.sll_ifindex
;
436 struct interface
*iface
=
437 odhcpd_get_interface_by_index(destiface
);
439 if (!iface
&& addr
.nl
.nl_family
!= AF_NETLINK
)
442 char ipbuf
[INET6_ADDRSTRLEN
] = "kernel";
443 if (addr
.ll
.sll_family
== AF_PACKET
&&
444 len
>= (ssize_t
)sizeof(struct ip6_hdr
))
445 inet_ntop(AF_INET6
, &data_buf
[8], ipbuf
, sizeof(ipbuf
));
446 else if (addr
.in6
.sin6_family
== AF_INET6
)
447 inet_ntop(AF_INET6
, &addr
.in6
.sin6_addr
, ipbuf
, sizeof(ipbuf
));
448 else if (addr
.in
.sin_family
== AF_INET
)
449 inet_ntop(AF_INET
, &addr
.in
.sin_addr
, ipbuf
, sizeof(ipbuf
));
451 syslog(LOG_DEBUG
, "--");
452 syslog(LOG_DEBUG
, "Received %li Bytes from %s%%%s", (long)len
,
453 ipbuf
, (iface
) ? iface
->ifname
: "netlink");
455 e
->handle_dgram(&addr
, data_buf
, len
, iface
, dest
);
459 // Register events for the multiplexer
460 int odhcpd_register(struct odhcpd_event
*event
)
462 event
->uloop
.cb
= odhcpd_receive_packets
;
463 return uloop_fd_add(&event
->uloop
, ULOOP_READ
);
466 void odhcpd_process(struct odhcpd_event
*event
)
468 odhcpd_receive_packets(&event
->uloop
, 0);
471 int odhcpd_urandom(void *data
, size_t len
)
473 return read(urandom_fd
, data
, len
);
477 time_t odhcpd_time(void)
480 syscall(SYS_clock_gettime
, CLOCK_MONOTONIC
, &ts
);
485 static const char hexdigits
[] = "0123456789abcdef";
486 static const int8_t hexvals
[] = {
487 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
488 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
489 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
490 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
491 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
492 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
493 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
494 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
497 ssize_t
odhcpd_unhexlify(uint8_t *dst
, size_t len
, const char *src
)
500 for (c
= 0; c
< len
&& src
[0] && src
[1]; ++c
) {
501 int8_t x
= (int8_t)*src
++;
502 int8_t y
= (int8_t)*src
++;
503 if (x
< 0 || (x
= hexvals
[x
]) < 0
504 || y
< 0 || (y
= hexvals
[y
]) < 0)
507 while (((int8_t)*src
) < 0 ||
508 (*src
&& hexvals
[(uint8_t)*src
] < 0))
516 void odhcpd_hexlify(char *dst
, const uint8_t *src
, size_t len
)
518 for (size_t i
= 0; i
< len
; ++i
) {
519 *dst
++ = hexdigits
[src
[i
] >> 4];
520 *dst
++ = hexdigits
[src
[i
] & 0x0f];
526 int odhcpd_bmemcmp(const void *av
, const void *bv
, size_t bits
)
528 const uint8_t *a
= av
, *b
= bv
;
529 size_t bytes
= bits
/ 8;
532 int res
= memcmp(a
, b
, bytes
);
533 if (res
== 0 && bits
> 0)
534 res
= (a
[bytes
] >> (8 - bits
)) - (b
[bytes
] >> (8 - bits
));
540 void odhcpd_bmemcpy(void *av
, const void *bv
, size_t bits
)
543 const uint8_t *b
= bv
;
545 size_t bytes
= bits
/ 8;
550 uint8_t mask
= (1 << (8 - bits
)) - 1;
551 a
[bytes
] = (a
[bytes
] & mask
) | ((~mask
) & b
[bytes
]);