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>
35 #include <linux/if_addr.h>
36 #include <linux/neighbour.h>
37 #include <linux/rtnetlink.h>
39 #include <sys/socket.h>
40 #include <sys/ioctl.h>
41 #include <sys/epoll.h>
42 #include <sys/types.h>
44 #include <sys/syscall.h>
46 #include <netlink/msg.h>
47 #include <netlink/socket.h>
48 #include <netlink/attr.h>
49 #include <libubox/uloop.h>
54 static int ioctl_sock
;
55 static struct nl_sock
*rtnl_socket
= NULL
;
56 static int urandom_fd
= -1;
58 static void sighandler(_unused
int signal
)
63 static void print_usage(const char *app
)
67 " -h, --help Print this help\n"
68 " -l level Specify log level 0..7 (default %d)\n",
73 int main(int argc
, char **argv
)
75 openlog("odhcpd", LOG_PERROR
| LOG_PID
, LOG_DAEMON
);
78 while ((opt
= getopt(argc
, argv
, "hl:")) != -1) {
84 config
.log_level
= (atoi(optarg
) & LOG_PRIMASK
);
85 fprintf(stderr
, "Log level set to %d\n", config
.log_level
);
89 setlogmask(LOG_UPTO(config
.log_level
));
93 syslog(LOG_ERR
, "Must be run as root!");
97 ioctl_sock
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, 0);
99 if (!(rtnl_socket
= odhcpd_create_nl_socket(NETLINK_ROUTE
))) {
100 syslog(LOG_ERR
, "Unable to open nl socket: %s", strerror(errno
));
104 if ((urandom_fd
= open("/dev/urandom", O_RDONLY
| O_CLOEXEC
)) < 0)
107 signal(SIGUSR1
, SIG_IGN
);
108 signal(SIGINT
, sighandler
);
109 signal(SIGTERM
, sighandler
);
127 struct nl_sock
*odhcpd_create_nl_socket(int protocol
)
129 struct nl_sock
*nl_sock
;
131 nl_sock
= nl_socket_alloc();
135 if (nl_connect(nl_sock
, protocol
) < 0)
142 nl_socket_free(nl_sock
);
148 // Read IPv6 MTU for interface
149 int odhcpd_get_interface_config(const char *ifname
, const char *what
)
152 const char *sysctl_pattern
= "/proc/sys/net/ipv6/conf/%s/%s";
153 snprintf(buf
, sizeof(buf
), sysctl_pattern
, ifname
, what
);
155 int fd
= open(buf
, O_RDONLY
);
156 ssize_t len
= read(fd
, buf
, sizeof(buf
) - 1);
167 // Read IPv6 MAC for interface
168 int odhcpd_get_mac(const struct interface
*iface
, uint8_t mac
[6])
171 memset(&ifr
, 0, sizeof(ifr
));
172 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
));
173 if (ioctl(ioctl_sock
, SIOCGIFHWADDR
, &ifr
) < 0)
175 memcpy(mac
, ifr
.ifr_hwaddr
.sa_data
, 6);
180 // Forwards a packet on a specific interface
181 ssize_t
odhcpd_send(int socket
, struct sockaddr_in6
*dest
,
182 struct iovec
*iov
, size_t iov_len
,
183 const struct interface
*iface
)
186 uint8_t cmsg_buf
[CMSG_SPACE(sizeof(struct in6_pktinfo
))] = {0};
187 struct msghdr msg
= {
188 .msg_name
= (void *) dest
,
189 .msg_namelen
= sizeof(*dest
),
191 .msg_iovlen
= iov_len
,
192 .msg_control
= cmsg_buf
,
193 .msg_controllen
= sizeof(cmsg_buf
),
197 // Set control data (define destination interface)
198 struct cmsghdr
*chdr
= CMSG_FIRSTHDR(&msg
);
199 chdr
->cmsg_level
= IPPROTO_IPV6
;
200 chdr
->cmsg_type
= IPV6_PKTINFO
;
201 chdr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
202 struct in6_pktinfo
*pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(chdr
);
203 pktinfo
->ipi6_ifindex
= iface
->ifindex
;
205 // Also set scope ID if link-local
206 if (IN6_IS_ADDR_LINKLOCAL(&dest
->sin6_addr
)
207 || IN6_IS_ADDR_MC_LINKLOCAL(&dest
->sin6_addr
))
208 dest
->sin6_scope_id
= iface
->ifindex
;
210 char ipbuf
[INET6_ADDRSTRLEN
];
211 inet_ntop(AF_INET6
, &dest
->sin6_addr
, ipbuf
, sizeof(ipbuf
));
213 ssize_t sent
= sendmsg(socket
, &msg
, MSG_DONTWAIT
);
215 syslog(LOG_NOTICE
, "Failed to send to %s%%%s (%s)",
216 ipbuf
, iface
->ifname
, strerror(errno
));
218 syslog(LOG_DEBUG
, "Sent %li bytes to %s%%%s",
219 (long)sent
, ipbuf
, iface
->ifname
);
226 struct odhcpd_ipaddr
**addrs
;
231 static int cb_valid_handler(struct nl_msg
*msg
, void *arg
)
233 struct addr_info
*ctxt
= (struct addr_info
*)arg
;
234 struct odhcpd_ipaddr
*addrs
= *(ctxt
->addrs
);
235 struct nlmsghdr
*hdr
= nlmsg_hdr(msg
);
236 struct ifaddrmsg
*ifa
;
237 struct nlattr
*nla
[__IFA_MAX
], *nla_addr
= NULL
;
239 if (hdr
->nlmsg_type
!= RTM_NEWADDR
)
242 ifa
= NLMSG_DATA(hdr
);
243 if (ifa
->ifa_scope
!= RT_SCOPE_UNIVERSE
||
244 (ctxt
->af
!= ifa
->ifa_family
) ||
245 (ctxt
->ifindex
&& ifa
->ifa_index
!= (unsigned)ctxt
->ifindex
))
248 nlmsg_parse(hdr
, sizeof(*ifa
), nla
, __IFA_MAX
- 1, NULL
);
250 switch (ifa
->ifa_family
) {
252 if (nla
[IFA_ADDRESS
])
253 nla_addr
= nla
[IFA_ADDRESS
];
258 nla_addr
= nla
[IFA_LOCAL
];
267 addrs
= realloc(addrs
, sizeof(*addrs
)*(ctxt
->ret
+ 1));
271 memset(&addrs
[ctxt
->ret
], 0, sizeof(addrs
[ctxt
->ret
]));
272 addrs
[ctxt
->ret
].prefix
= ifa
->ifa_prefixlen
;
274 nla_memcpy(&addrs
[ctxt
->ret
].addr
, nla_addr
,
275 sizeof(addrs
[ctxt
->ret
].addr
));
277 if (nla
[IFA_BROADCAST
])
278 nla_memcpy(&addrs
[ctxt
->ret
].broadcast
, nla
[IFA_BROADCAST
],
279 sizeof(addrs
[ctxt
->ret
].broadcast
));
281 if (nla
[IFA_CACHEINFO
]) {
282 struct ifa_cacheinfo
*ifc
= nla_data(nla
[IFA_CACHEINFO
]);
284 addrs
[ctxt
->ret
].preferred
= ifc
->ifa_prefered
;
285 addrs
[ctxt
->ret
].valid
= ifc
->ifa_valid
;
288 if (ifa
->ifa_flags
& IFA_F_DEPRECATED
)
289 addrs
[ctxt
->ret
].preferred
= 0;
292 *(ctxt
->addrs
) = addrs
;
297 static int cb_finish_handler(_unused
struct nl_msg
*msg
, void *arg
)
299 struct addr_info
*ctxt
= (struct addr_info
*)arg
;
306 static int cb_error_handler(_unused
struct sockaddr_nl
*nla
, struct nlmsgerr
*err
,
309 struct addr_info
*ctxt
= (struct addr_info
*)arg
;
312 ctxt
->ret
= err
->error
;
317 static int prefix_cmp(const void *va
, const void *vb
)
319 const struct odhcpd_ipaddr
*a
= va
, *b
= vb
;
320 return (ntohl(a
->addr
.in
.s_addr
) < ntohl(b
->addr
.in
.s_addr
)) ? 1 :
321 (ntohl(a
->addr
.in
.s_addr
) > ntohl(b
->addr
.in
.s_addr
)) ? -1 : 0;
324 // compare IPv6 prefixes
325 static int prefix6_cmp(const void *va
, const void *vb
)
327 const struct odhcpd_ipaddr
*a
= va
, *b
= vb
;
328 uint32_t a_pref
= IN6_IS_ADDR_ULA(&a
->addr
.in6
) ? 1 : a
->preferred
;
329 uint32_t b_pref
= IN6_IS_ADDR_ULA(&b
->addr
.in6
) ? 1 : b
->preferred
;
330 return (a_pref
< b_pref
) ? 1 : (a_pref
> b_pref
) ? -1 : 0;
333 // Detect an IPV6-address currently assigned to the given interface
334 ssize_t
odhcpd_get_interface_addresses(int ifindex
, bool v6
, struct odhcpd_ipaddr
**addrs
)
337 struct ifaddrmsg ifa
= {
338 .ifa_family
= v6
? AF_INET6
: AF_INET
,
342 .ifa_index
= ifindex
, };
343 struct nl_cb
*cb
= nl_cb_alloc(NL_CB_DEFAULT
);
344 struct addr_info ctxt
= {
346 .af
= v6
? AF_INET6
: AF_INET
,
357 msg
= nlmsg_alloc_simple(RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
);
364 nlmsg_append(msg
, &ifa
, sizeof(ifa
), 0);
366 nl_cb_set(cb
, NL_CB_VALID
, NL_CB_CUSTOM
, cb_valid_handler
, &ctxt
);
367 nl_cb_set(cb
, NL_CB_FINISH
, NL_CB_CUSTOM
, cb_finish_handler
, &ctxt
);
368 nl_cb_err(cb
, NL_CB_CUSTOM
, cb_error_handler
, &ctxt
);
370 nl_send_auto_complete(rtnl_socket
, msg
);
371 while (ctxt
.pending
> 0)
372 nl_recvmsgs(rtnl_socket
, cb
);
379 time_t now
= odhcpd_time();
380 struct odhcpd_ipaddr
*addr
= *addrs
;
382 qsort(addr
, ctxt
.ret
, sizeof(*addr
), v6
? prefix6_cmp
: prefix_cmp
);
384 for (ssize_t i
= 0; i
< ctxt
.ret
; ++i
) {
385 if (addr
[i
].preferred
< UINT32_MAX
- now
)
386 addr
[i
].preferred
+= now
;
388 if (addr
[i
].valid
< UINT32_MAX
- now
)
389 addr
[i
].valid
+= now
;
398 static int odhcpd_get_linklocal_interface_address(int ifindex
, struct in6_addr
*lladdr
)
401 struct sockaddr_in6 addr
= {AF_INET6
, 0, 0, ALL_IPV6_ROUTERS
, ifindex
};
402 socklen_t alen
= sizeof(addr
);
403 int sock
= socket(AF_INET6
, SOCK_RAW
, IPPROTO_ICMPV6
);
405 if (!connect(sock
, (struct sockaddr
*)&addr
, sizeof(addr
)) &&
406 !getsockname(sock
, (struct sockaddr
*)&addr
, &alen
)) {
407 *lladdr
= addr
.sin6_addr
;
417 * DNS address selection criteria order :
418 * - use IPv6 address with valid lifetime if none is yet selected
419 * - use IPv6 address with a preferred lifetime if the already selected IPv6 address is deprecated
420 * - use an IPv6 ULA address if the already selected IPv6 address is not an ULA address
421 * - use the IPv6 address with the longest preferred lifetime
423 int odhcpd_get_interface_dns_addr(const struct interface
*iface
, struct in6_addr
*addr
)
425 time_t now
= odhcpd_time();
428 for (size_t i
= 0; i
< iface
->ia_addr_len
; ++i
) {
429 if (iface
->ia_addr
[i
].valid
<= (uint32_t)now
)
437 if (iface
->ia_addr
[m
].preferred
>= (uint32_t)now
&&
438 iface
->ia_addr
[i
].preferred
< (uint32_t)now
)
441 if (IN6_IS_ADDR_ULA(&iface
->ia_addr
[i
].addr
.in6
)) {
442 if (!IN6_IS_ADDR_ULA(&iface
->ia_addr
[m
].addr
.in6
)) {
446 } else if (IN6_IS_ADDR_ULA(&iface
->ia_addr
[m
].addr
.in6
))
449 if (iface
->ia_addr
[i
].preferred
> iface
->ia_addr
[m
].preferred
)
454 *addr
= iface
->ia_addr
[m
].addr
.in6
;
458 return odhcpd_get_linklocal_interface_address(iface
->ifindex
, addr
);
461 int odhcpd_setup_route(const struct in6_addr
*addr
, const int prefixlen
,
462 const struct interface
*iface
, const struct in6_addr
*gw
,
463 const uint32_t metric
, const bool add
)
467 .rtm_family
= AF_INET6
,
468 .rtm_dst_len
= prefixlen
,
470 .rtm_table
= RT_TABLE_MAIN
,
471 .rtm_protocol
= (add
? RTPROT_STATIC
: RTPROT_UNSPEC
),
472 .rtm_scope
= (add
? (gw
? RT_SCOPE_UNIVERSE
: RT_SCOPE_LINK
) : RT_SCOPE_NOWHERE
),
473 .rtm_type
= (add
? RTN_UNICAST
: RTN_UNSPEC
),
477 msg
= nlmsg_alloc_simple(add
? RTM_NEWROUTE
: RTM_DELROUTE
,
478 add
? NLM_F_CREATE
| NLM_F_REPLACE
: 0);
482 nlmsg_append(msg
, &rtm
, sizeof(rtm
), 0);
484 nla_put(msg
, RTA_DST
, sizeof(*addr
), addr
);
485 nla_put_u32(msg
, RTA_OIF
, iface
->ifindex
);
486 nla_put_u32(msg
, RTA_PRIORITY
, metric
);
489 nla_put(msg
, RTA_GATEWAY
, sizeof(*gw
), gw
);
491 ret
= nl_send_auto_complete(rtnl_socket
, msg
);
497 return nl_wait_for_ack(rtnl_socket
);
500 int odhcpd_setup_proxy_neigh(const struct in6_addr
*addr
,
501 const struct interface
*iface
, const bool add
)
505 .ndm_family
= AF_INET6
,
506 .ndm_flags
= NTF_PROXY
,
507 .ndm_ifindex
= iface
->ifindex
,
509 int ret
= 0, flags
= NLM_F_REQUEST
;
512 flags
|= NLM_F_REPLACE
| NLM_F_CREATE
;
514 msg
= nlmsg_alloc_simple(add
? RTM_NEWNEIGH
: RTM_DELNEIGH
, flags
);
518 nlmsg_append(msg
, &ndm
, sizeof(ndm
), 0);
520 nla_put(msg
, NDA_DST
, sizeof(*addr
), addr
);
522 ret
= nl_send_auto_complete(rtnl_socket
, msg
);
528 return nl_wait_for_ack(rtnl_socket
);
531 struct interface
* odhcpd_get_interface_by_index(int ifindex
)
533 struct interface
*iface
;
534 list_for_each_entry(iface
, &interfaces
, head
)
535 if (iface
->ifindex
== ifindex
)
542 struct interface
* odhcpd_get_interface_by_name(const char *name
)
544 struct interface
*iface
;
545 list_for_each_entry(iface
, &interfaces
, head
)
546 if (!strcmp(iface
->ifname
, name
))
553 struct interface
* odhcpd_get_master_interface(void)
555 struct interface
*iface
;
556 list_for_each_entry(iface
, &interfaces
, head
)
564 // Convenience function to receive and do basic validation of packets
565 static void odhcpd_receive_packets(struct uloop_fd
*u
, _unused
unsigned int events
)
567 struct odhcpd_event
*e
= container_of(u
, struct odhcpd_event
, uloop
);
569 uint8_t data_buf
[8192], cmsg_buf
[128];
571 struct sockaddr_in6 in6
;
572 struct sockaddr_in in
;
573 struct sockaddr_ll ll
;
574 struct sockaddr_nl nl
;
579 socklen_t ret_len
= sizeof(ret
);
580 getsockopt(u
->fd
, SOL_SOCKET
, SO_ERROR
, &ret
, &ret_len
);
583 e
->handle_error(e
, ret
);
592 struct iovec iov
= {data_buf
, sizeof(data_buf
)};
593 struct msghdr msg
= {
594 .msg_name
= (void *) &addr
,
595 .msg_namelen
= sizeof(addr
),
598 .msg_control
= cmsg_buf
,
599 .msg_controllen
= sizeof(cmsg_buf
),
603 ssize_t len
= recvmsg(u
->fd
, &msg
, MSG_DONTWAIT
);
612 // Extract destination interface
616 struct in6_pktinfo
*pktinfo
;
617 struct in_pktinfo
*pkt4info
;
618 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
; ch
= CMSG_NXTHDR(&msg
, ch
)) {
619 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
620 ch
->cmsg_type
== IPV6_PKTINFO
) {
621 pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(ch
);
622 destiface
= pktinfo
->ipi6_ifindex
;
623 dest
= &pktinfo
->ipi6_addr
;
624 } else if (ch
->cmsg_level
== IPPROTO_IP
&&
625 ch
->cmsg_type
== IP_PKTINFO
) {
626 pkt4info
= (struct in_pktinfo
*)CMSG_DATA(ch
);
627 destiface
= pkt4info
->ipi_ifindex
;
628 dest
= &pkt4info
->ipi_addr
;
629 } else if (ch
->cmsg_level
== IPPROTO_IPV6
&&
630 ch
->cmsg_type
== IPV6_HOPLIMIT
) {
631 hlim
= (int*)CMSG_DATA(ch
);
635 // Check hoplimit if received
636 if (hlim
&& *hlim
!= 255)
639 // Detect interface for packet sockets
640 if (addr
.ll
.sll_family
== AF_PACKET
)
641 destiface
= addr
.ll
.sll_ifindex
;
643 struct interface
*iface
=
644 odhcpd_get_interface_by_index(destiface
);
646 if (!iface
&& addr
.nl
.nl_family
!= AF_NETLINK
)
649 char ipbuf
[INET6_ADDRSTRLEN
] = "kernel";
650 if (addr
.ll
.sll_family
== AF_PACKET
&&
651 len
>= (ssize_t
)sizeof(struct ip6_hdr
))
652 inet_ntop(AF_INET6
, &data_buf
[8], ipbuf
, sizeof(ipbuf
));
653 else if (addr
.in6
.sin6_family
== AF_INET6
)
654 inet_ntop(AF_INET6
, &addr
.in6
.sin6_addr
, ipbuf
, sizeof(ipbuf
));
655 else if (addr
.in
.sin_family
== AF_INET
)
656 inet_ntop(AF_INET
, &addr
.in
.sin_addr
, ipbuf
, sizeof(ipbuf
));
658 syslog(LOG_DEBUG
, "Received %li Bytes from %s%%%s", (long)len
,
659 ipbuf
, (iface
) ? iface
->ifname
: "netlink");
661 e
->handle_dgram(&addr
, data_buf
, len
, iface
, dest
);
665 // Register events for the multiplexer
666 int odhcpd_register(struct odhcpd_event
*event
)
668 event
->uloop
.cb
= odhcpd_receive_packets
;
669 return uloop_fd_add(&event
->uloop
, ULOOP_READ
|
670 ((event
->handle_error
) ? ULOOP_ERROR_CB
: 0));
673 int odhcpd_deregister(struct odhcpd_event
*event
)
675 event
->uloop
.cb
= NULL
;
676 return uloop_fd_delete(&event
->uloop
);
679 void odhcpd_process(struct odhcpd_event
*event
)
681 odhcpd_receive_packets(&event
->uloop
, 0);
684 int odhcpd_urandom(void *data
, size_t len
)
686 return read(urandom_fd
, data
, len
);
690 time_t odhcpd_time(void)
693 syscall(SYS_clock_gettime
, CLOCK_MONOTONIC
, &ts
);
698 static const char hexdigits
[] = "0123456789abcdef";
699 static const int8_t hexvals
[] = {
700 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
701 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
702 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
703 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
704 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
705 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
706 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
707 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
710 ssize_t
odhcpd_unhexlify(uint8_t *dst
, size_t len
, const char *src
)
713 for (c
= 0; c
< len
&& src
[0] && src
[1]; ++c
) {
714 int8_t x
= (int8_t)*src
++;
715 int8_t y
= (int8_t)*src
++;
716 if (x
< 0 || (x
= hexvals
[x
]) < 0
717 || y
< 0 || (y
= hexvals
[y
]) < 0)
720 while (((int8_t)*src
) < 0 ||
721 (*src
&& hexvals
[(uint8_t)*src
] < 0))
729 void odhcpd_hexlify(char *dst
, const uint8_t *src
, size_t len
)
731 for (size_t i
= 0; i
< len
; ++i
) {
732 *dst
++ = hexdigits
[src
[i
] >> 4];
733 *dst
++ = hexdigits
[src
[i
] & 0x0f];
739 int odhcpd_bmemcmp(const void *av
, const void *bv
, size_t bits
)
741 const uint8_t *a
= av
, *b
= bv
;
742 size_t bytes
= bits
/ 8;
745 int res
= memcmp(a
, b
, bytes
);
746 if (res
== 0 && bits
> 0)
747 res
= (a
[bytes
] >> (8 - bits
)) - (b
[bytes
] >> (8 - bits
));
753 void odhcpd_bmemcpy(void *av
, const void *bv
, size_t bits
)
756 const uint8_t *b
= bv
;
758 size_t bytes
= bits
/ 8;
763 uint8_t mask
= (1 << (8 - bits
)) - 1;
764 a
[bytes
] = (a
[bytes
] & mask
) | ((~mask
) & b
[bytes
]);