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;
54 openlog("odhcpd", LOG_PERROR
| LOG_PID
, LOG_DAEMON
);
55 setlogmask(LOG_UPTO(LOG_INFO
));
59 syslog(LOG_ERR
, "Must be run as root!");
63 ioctl_sock
= socket(AF_INET
, SOCK_DGRAM
| SOCK_CLOEXEC
, 0);
65 if ((rtnl_socket
= odhcpd_open_rtnl()) < 0) {
66 syslog(LOG_ERR
, "Unable to open socket: %s", strerror(errno
));
70 if ((urandom_fd
= open("/dev/urandom", O_RDONLY
| O_CLOEXEC
)) < 0)
73 signal(SIGUSR1
, SIG_IGN
);
91 int odhcpd_open_rtnl(void)
93 int sock
= socket(AF_NETLINK
, SOCK_RAW
| SOCK_CLOEXEC
, NETLINK_ROUTE
);
95 // Connect to the kernel netlink interface
96 struct sockaddr_nl nl
= {.nl_family
= AF_NETLINK
};
97 if (connect(sock
, (struct sockaddr
*)&nl
, sizeof(nl
))) {
98 syslog(LOG_ERR
, "Failed to connect to kernel rtnetlink: %s",
107 // Read IPv6 MTU for interface
108 int odhcpd_get_interface_mtu(const char *ifname
)
111 const char *sysctl_pattern
= "/proc/sys/net/ipv6/conf/%s/mtu";
112 snprintf(buf
, sizeof(buf
), sysctl_pattern
, ifname
);
114 int fd
= open(buf
, O_RDONLY
);
115 ssize_t len
= read(fd
, buf
, sizeof(buf
) - 1);
128 // Read IPv6 MAC for interface
129 int odhcpd_get_mac(const struct interface
*iface
, uint8_t mac
[6])
132 memset(&ifr
, 0, sizeof(ifr
));
133 strncpy(ifr
.ifr_name
, iface
->ifname
, sizeof(ifr
.ifr_name
));
134 if (ioctl(ioctl_sock
, SIOCGIFHWADDR
, &ifr
) < 0)
136 memcpy(mac
, ifr
.ifr_hwaddr
.sa_data
, 6);
141 // Forwards a packet on a specific interface
142 ssize_t
odhcpd_send(int socket
, struct sockaddr_in6
*dest
,
143 struct iovec
*iov
, size_t iov_len
,
144 const struct interface
*iface
)
147 uint8_t cmsg_buf
[CMSG_SPACE(sizeof(struct in6_pktinfo
))] = {0};
148 struct msghdr msg
= {(void*)dest
, sizeof(*dest
), iov
, iov_len
,
149 cmsg_buf
, sizeof(cmsg_buf
), 0};
151 // Set control data (define destination interface)
152 struct cmsghdr
*chdr
= CMSG_FIRSTHDR(&msg
);
153 chdr
->cmsg_level
= IPPROTO_IPV6
;
154 chdr
->cmsg_type
= IPV6_PKTINFO
;
155 chdr
->cmsg_len
= CMSG_LEN(sizeof(struct in6_pktinfo
));
156 struct in6_pktinfo
*pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(chdr
);
157 pktinfo
->ipi6_ifindex
= iface
->ifindex
;
159 // Also set scope ID if link-local
160 if (IN6_IS_ADDR_LINKLOCAL(&dest
->sin6_addr
)
161 || IN6_IS_ADDR_MC_LINKLOCAL(&dest
->sin6_addr
))
162 dest
->sin6_scope_id
= iface
->ifindex
;
164 // IPV6_PKTINFO doesn't really work for IPv6-raw sockets (bug?)
165 if (dest
->sin6_port
== 0) {
166 msg
.msg_control
= NULL
;
167 msg
.msg_controllen
= 0;
170 char ipbuf
[INET6_ADDRSTRLEN
];
171 inet_ntop(AF_INET6
, &dest
->sin6_addr
, ipbuf
, sizeof(ipbuf
));
173 ssize_t sent
= sendmsg(socket
, &msg
, MSG_DONTWAIT
);
175 syslog(LOG_WARNING
, "Failed to send to %s%%%s (%s)",
176 ipbuf
, iface
->ifname
, strerror(errno
));
178 syslog(LOG_DEBUG
, "Sent %li bytes to %s%%%s",
179 (long)sent
, ipbuf
, iface
->ifname
);
184 // Detect an IPV6-address currently assigned to the given interface
185 ssize_t
odhcpd_get_interface_addresses(int ifindex
,
186 struct odhcpd_ipaddr
*addrs
, size_t cnt
)
190 struct ifaddrmsg ifa
;
191 } req
= {{sizeof(req
), RTM_GETADDR
, NLM_F_REQUEST
| NLM_F_DUMP
,
192 ++rtnl_seq
, 0}, {AF_INET6
, 0, 0, 0, ifindex
}};
193 if (send(rtnl_socket
, &req
, sizeof(req
), 0) < (ssize_t
)sizeof(req
))
197 ssize_t len
= 0, ret
= 0;
199 for (struct nlmsghdr
*nhm
= NULL
; ; nhm
= NLMSG_NEXT(nhm
, len
)) {
200 while (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
201 len
= recv(rtnl_socket
, buf
, sizeof(buf
), 0);
202 nhm
= (struct nlmsghdr
*)buf
;
203 if (len
< 0 || !NLMSG_OK(nhm
, (size_t)len
)) {
211 if (nhm
->nlmsg_type
!= RTM_NEWADDR
)
214 // Skip address but keep clearing socket buffer
215 if (ret
>= (ssize_t
)cnt
)
218 struct ifaddrmsg
*ifa
= NLMSG_DATA(nhm
);
219 if (ifa
->ifa_scope
!= RT_SCOPE_UNIVERSE
||
220 ifa
->ifa_index
!= (unsigned)ifindex
)
223 struct rtattr
*rta
= (struct rtattr
*)&ifa
[1];
224 size_t alen
= NLMSG_PAYLOAD(nhm
, sizeof(*ifa
));
225 memset(&addrs
[ret
], 0, sizeof(addrs
[ret
]));
226 addrs
[ret
].prefix
= ifa
->ifa_prefixlen
;
228 while (RTA_OK(rta
, alen
)) {
229 if (rta
->rta_type
== IFA_ADDRESS
) {
230 memcpy(&addrs
[ret
].addr
, RTA_DATA(rta
),
231 sizeof(struct in6_addr
));
232 } else if (rta
->rta_type
== IFA_CACHEINFO
) {
233 struct ifa_cacheinfo
*ifc
= RTA_DATA(rta
);
234 addrs
[ret
].preferred
= ifc
->ifa_prefered
;
235 addrs
[ret
].valid
= ifc
->ifa_valid
;
238 rta
= RTA_NEXT(rta
, alen
);
241 if (ifa
->ifa_flags
& IFA_F_DEPRECATED
)
242 addrs
[ret
].preferred
= 0;
244 addrs
[ret
].has_class
= false;
245 addrs
[ret
].class = 0;
247 struct interface
*iface
= odhcpd_get_interface_by_index(ifindex
);
249 addrs
[ret
].has_class
= ubus_get_class(iface
->ifname
,
250 &addrs
[ret
].addr
, &addrs
[ret
].class);
259 struct interface
* odhcpd_get_interface_by_index(int ifindex
)
261 struct interface
*iface
;
262 list_for_each_entry(iface
, &interfaces
, head
)
263 if (iface
->ifindex
== ifindex
)
270 struct interface
* odhcpd_get_interface_by_name(const char *name
)
272 struct interface
*iface
;
273 list_for_each_entry(iface
, &interfaces
, head
)
274 if (!strcmp(iface
->ifname
, name
))
281 struct interface
* odhcpd_get_master_interface(void)
283 struct interface
*iface
;
284 list_for_each_entry(iface
, &interfaces
, head
)
292 // Convenience function to receive and do basic validation of packets
293 static void odhcpd_receive_packets(struct uloop_fd
*u
, _unused
unsigned int events
)
295 struct odhcpd_event
*e
= container_of(u
, struct odhcpd_event
, uloop
);
297 uint8_t data_buf
[RELAYD_BUFFER_SIZE
], cmsg_buf
[128];
299 struct sockaddr_in6 in6
;
300 struct sockaddr_in in
;
301 struct sockaddr_ll ll
;
302 struct sockaddr_nl nl
;
306 struct iovec iov
= {data_buf
, sizeof(data_buf
)};
307 struct msghdr msg
= {&addr
, sizeof(addr
), &iov
, 1,
308 cmsg_buf
, sizeof(cmsg_buf
), 0};
310 ssize_t len
= recvmsg(u
->fd
, &msg
, MSG_DONTWAIT
);
319 // Extract destination interface
322 struct in6_pktinfo
*pktinfo
;
323 struct in_pktinfo
*pkt4info
;
324 for (struct cmsghdr
*ch
= CMSG_FIRSTHDR(&msg
); ch
!= NULL
; ch
= CMSG_NXTHDR(&msg
, ch
)) {
325 if (ch
->cmsg_level
== IPPROTO_IPV6
&&
326 ch
->cmsg_type
== IPV6_PKTINFO
) {
327 pktinfo
= (struct in6_pktinfo
*)CMSG_DATA(ch
);
328 destiface
= pktinfo
->ipi6_ifindex
;
329 } else if (ch
->cmsg_level
== IPPROTO_IP
&&
330 ch
->cmsg_type
== IP_PKTINFO
) {
331 pkt4info
= (struct in_pktinfo
*)CMSG_DATA(ch
);
332 destiface
= pkt4info
->ipi_ifindex
;
333 } else if (ch
->cmsg_level
== IPPROTO_IPV6
&&
334 ch
->cmsg_type
== IPV6_HOPLIMIT
) {
335 hlim
= (int*)CMSG_DATA(ch
);
339 // Check hoplimit if received
340 if (hlim
&& *hlim
!= 255)
343 // Detect interface for packet sockets
344 if (addr
.ll
.sll_family
== AF_PACKET
)
345 destiface
= addr
.ll
.sll_ifindex
;
347 struct interface
*iface
=
348 odhcpd_get_interface_by_index(destiface
);
350 if (!iface
&& addr
.nl
.nl_family
!= AF_NETLINK
)
353 char ipbuf
[INET6_ADDRSTRLEN
] = "kernel";
354 if (addr
.ll
.sll_family
== AF_PACKET
&&
355 len
>= (ssize_t
)sizeof(struct ip6_hdr
))
356 inet_ntop(AF_INET6
, &data_buf
[8], ipbuf
, sizeof(ipbuf
));
357 else if (addr
.in6
.sin6_family
== AF_INET6
)
358 inet_ntop(AF_INET6
, &addr
.in6
.sin6_addr
, ipbuf
, sizeof(ipbuf
));
359 else if (addr
.in
.sin_family
== AF_INET
)
360 inet_ntop(AF_INET
, &addr
.in
.sin_addr
, ipbuf
, sizeof(ipbuf
));
362 syslog(LOG_DEBUG
, "--");
363 syslog(LOG_DEBUG
, "Received %li Bytes from %s%%%s", (long)len
,
364 ipbuf
, (iface
) ? iface
->ifname
: "netlink");
366 e
->handle_dgram(&addr
, data_buf
, len
, iface
);
370 // Register events for the multiplexer
371 int odhcpd_register(struct odhcpd_event
*event
)
373 event
->uloop
.cb
= odhcpd_receive_packets
;
374 return uloop_fd_add(&event
->uloop
, ULOOP_READ
);
377 void odhcpd_urandom(void *data
, size_t len
)
379 read(urandom_fd
, data
, len
);
383 time_t odhcpd_time(void)
386 syscall(SYS_clock_gettime
, CLOCK_MONOTONIC
, &ts
);
391 static const char hexdigits
[] = "0123456789abcdef";
392 static const int8_t hexvals
[] = {
393 -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1,
394 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
395 -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
396 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
397 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
398 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
399 -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
400 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
403 ssize_t
odhcpd_unhexlify(uint8_t *dst
, size_t len
, const char *src
)
406 for (c
= 0; c
< len
&& src
[0] && src
[1]; ++c
) {
407 int8_t x
= (int8_t)*src
++;
408 int8_t y
= (int8_t)*src
++;
409 if (x
< 0 || (x
= hexvals
[x
]) < 0
410 || y
< 0 || (y
= hexvals
[y
]) < 0)
413 while (((int8_t)*src
) < 0 ||
414 (*src
&& hexvals
[(uint8_t)*src
] < 0))
422 void odhcpd_hexlify(char *dst
, const uint8_t *src
, size_t len
)
424 for (size_t i
= 0; i
< len
; ++i
) {
425 *dst
++ = hexdigits
[src
[i
] >> 4];
426 *dst
++ = hexdigits
[src
[i
] & 0x0f];