2 * DHCP library with GLib integration
4 * Copyright (C) 2007-2012 Intel Corporation. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
29 #include <sys/ioctl.h>
33 #include <net/if_arp.h>
35 #include <netpacket/packet.h>
36 #include <net/ethernet.h>
37 #include <arpa/inet.h>
42 static const DHCPOption client_options[] = {
43 { OPTION_IP, 0x01 }, /* subnet-mask */
44 { OPTION_IP | OPTION_LIST, 0x03 }, /* routers */
45 { OPTION_IP | OPTION_LIST, 0x06 }, /* domain-name-servers */
46 { OPTION_STRING, 0x0c }, /* hostname */
47 { OPTION_STRING, 0x0f }, /* domain-name */
48 { OPTION_IP | OPTION_LIST, 0x2a }, /* ntp-servers */
49 { OPTION_U32, 0x33 }, /* dhcp-lease-time */
50 /* Options below will not be exposed to user */
51 { OPTION_IP, 0x32 }, /* requested-ip */
52 { OPTION_U8, 0x35 }, /* message-type */
53 { OPTION_U32, 0x36 }, /* server-id */
54 { OPTION_U16, 0x39 }, /* max-size */
55 { OPTION_STRING, 0x3c }, /* vendor */
56 { OPTION_STRING, 0x3d }, /* client-id */
57 { OPTION_STRING, 0xfc }, /* UNOFFICIAL proxy-pac */
58 { OPTION_UNKNOWN, 0x00 },
61 GDHCPOptionType dhcp_get_code_type(uint8_t code)
65 for (i = 0; client_options[i].code; i++) {
66 if (client_options[i].code == code)
67 return client_options[i].type;
70 return OPTION_UNKNOWN;
73 uint8_t *dhcp_get_option(struct dhcp_packet *packet, int code)
79 /* option bytes: [code][len][data1][data2]..[dataLEN] */
80 optionptr = packet->options;
81 rem = sizeof(packet->options);
85 /* Bad packet, malformed option field */
88 if (optionptr[OPT_CODE] == DHCP_PADDING) {
95 if (optionptr[OPT_CODE] == DHCP_END) {
96 if (overload & FILE_FIELD) {
97 overload &= ~FILE_FIELD;
99 optionptr = packet->file;
100 rem = sizeof(packet->file);
103 } else if (overload & SNAME_FIELD) {
104 overload &= ~SNAME_FIELD;
106 optionptr = packet->sname;
107 rem = sizeof(packet->sname);
115 len = 2 + optionptr[OPT_LEN];
119 continue; /* complain and return NULL */
121 if (optionptr[OPT_CODE] == code)
122 return optionptr + OPT_DATA;
124 if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD)
125 overload |= optionptr[OPT_DATA];
133 int dhcp_end_option(uint8_t *optionptr)
137 while (optionptr[i] != DHCP_END) {
138 if (optionptr[i] != DHCP_PADDING)
139 i += optionptr[i + OPT_LEN] + OPT_DATA - 1;
147 uint8_t *dhcpv6_get_option(struct dhcpv6_packet *packet, uint16_t pkt_len,
148 int code, uint16_t *option_len, int *option_count)
151 uint8_t *optionptr, *found = NULL;
152 uint16_t opt_code, opt_len, len;
154 optionptr = packet->options;
155 rem = pkt_len - 1 - 3;
161 opt_code = optionptr[0] << 8 | optionptr[1];
162 opt_len = len = optionptr[2] << 8 | optionptr[3];
163 len += 2 + 2; /* skip code and len */
172 if (opt_code == code) {
173 if (option_len != NULL)
174 *option_len = opt_len;
178 found = optionptr + 2 + 2;
188 if (option_count != NULL)
189 *option_count = count;
194 if (option_len != NULL)
196 if (option_count != NULL)
201 uint8_t *dhcpv6_get_sub_option(unsigned char *option, uint16_t max_len,
202 uint16_t *option_code, uint16_t *option_len)
207 rem = max_len - 2 - 2;
213 code = option[0] << 8 | option[1];
214 len = option[2] << 8 | option[3];
227 * Add an option (supplied in binary form) to the options.
228 * Option format: [code][len][data1][data2]..[dataLEN]
230 void dhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt)
233 uint8_t *optionptr = packet->options;
234 unsigned end = dhcp_end_option(optionptr);
236 len = OPT_DATA + addopt[OPT_LEN];
238 /* end position + (option code/length + addopt length) + end option */
239 if (end + len + 1 >= DHCP_OPTIONS_BUFSIZE)
240 /* option did not fit into the packet */
243 memcpy(optionptr + end, addopt, len);
245 optionptr[end + len] = DHCP_END;
249 * Add an option (supplied in binary form) to the options.
250 * Option format: [code][len][data1][data2]..[dataLEN]
252 void dhcpv6_add_binary_option(struct dhcpv6_packet *packet, uint16_t max_len,
253 uint16_t *pkt_len, uint8_t *addopt)
256 uint8_t *optionptr = packet->options;
258 len = 2 + 2 + (addopt[2] << 8 | addopt[3]);
260 /* end position + (option code/length + addopt length) */
261 if (*pkt_len + len >= max_len)
262 /* option did not fit into the packet */
265 memcpy(optionptr + *pkt_len, addopt, len);
269 void dhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code,
272 uint8_t option[6], len;
273 GDHCPOptionType type = dhcp_get_code_type(code);
275 if (type == OPTION_UNKNOWN)
278 option[OPT_CODE] = code;
280 len = dhcp_option_lengths[type & OPTION_TYPE_MASK];
281 option[OPT_LEN] = len;
283 #if __BYTE_ORDER == __BIG_ENDIAN
284 data <<= 8 * (4 - len);
287 dhcp_put_unaligned(data, (uint32_t *)(option + OPT_DATA));
288 dhcp_add_binary_option(packet, option);
293 void dhcp_init_header(struct dhcp_packet *packet, char type)
295 memset(packet, 0, sizeof(*packet));
297 packet->op = BOOTREQUEST;
303 packet->op = BOOTREPLY;
308 packet->cookie = htonl(DHCP_MAGIC);
309 packet->options[0] = DHCP_END;
311 dhcp_add_simple_option(packet, DHCP_MESSAGE_TYPE, type);
314 void dhcpv6_init_header(struct dhcpv6_packet *packet, uint8_t type)
318 memset(packet, 0, sizeof(*packet));
320 packet->message = type;
324 packet->transaction_id[0] = (id >> 16) & 0xff;
325 packet->transaction_id[1] = (id >> 8) & 0xff;
326 packet->transaction_id[2] = id & 0xff;
329 static gboolean check_vendor(uint8_t *option_vendor, const char *vendor)
331 uint8_t vendor_length = sizeof(vendor) - 1;
333 if (option_vendor[OPT_LEN - OPT_DATA] != vendor_length)
336 if (memcmp(option_vendor, vendor, vendor_length) != 0)
342 static void check_broken_vendor(struct dhcp_packet *packet)
346 if (packet->op != BOOTREQUEST)
349 vendor = dhcp_get_option(packet, DHCP_VENDOR);
353 if (check_vendor(vendor, "MSFT 98") == TRUE)
354 packet->flags |= htons(BROADCAST_FLAG);
357 int dhcp_recv_l3_packet(struct dhcp_packet *packet, int fd)
361 memset(packet, 0, sizeof(*packet));
363 n = read(fd, packet, sizeof(*packet));
367 if (packet->cookie != htonl(DHCP_MAGIC))
370 check_broken_vendor(packet);
375 int dhcpv6_recv_l3_packet(struct dhcpv6_packet **packet, unsigned char *buf,
380 n = read(fd, buf, buf_len);
384 *packet = (struct dhcpv6_packet *)buf;
389 /* TODO: Use glib checksum */
390 uint16_t dhcp_checksum(void *addr, int count)
393 * Compute Internet Checksum for "count" bytes
394 * beginning at location "addr".
397 uint16_t *source = (uint16_t *) addr;
400 /* This is the inner loop */
405 /* Add left-over byte, if any */
407 /* Make sure that the left-over byte is added correctly both
408 * with little and big endian hosts */
410 *(uint8_t *) &tmp = *(uint8_t *) source;
413 /* Fold 32-bit sum to 16 bits */
415 sum = (sum & 0xffff) + (sum >> 16);
420 #define IN6ADDR_ALL_DHCP_RELAY_AGENTS_AND_SERVERS_MC_INIT \
421 { { { 0xff,0x02,0,0,0,0,0,0,0,0,0,0,0,0x1,0,0x2 } } } /* ff02::1:2 */
422 static const struct in6_addr in6addr_all_dhcp_relay_agents_and_servers_mc =
423 IN6ADDR_ALL_DHCP_RELAY_AGENTS_AND_SERVERS_MC_INIT;
425 /* from netinet/in.h */
427 struct in6_addr ipi6_addr; /* src/dst IPv6 address */
428 unsigned int ipi6_ifindex; /* send/recv interface index */
431 int dhcpv6_send_packet(int index, struct dhcpv6_packet *dhcp_pkt, int len)
435 struct in6_pktinfo *pktinfo;
436 struct cmsghdr *cmsg;
438 struct sockaddr_in6 dst;
440 size_t control_buf_len;
442 fd = socket(PF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
446 memset(&dst, 0, sizeof(dst));
447 dst.sin6_family = AF_INET6;
448 dst.sin6_port = htons(DHCPV6_SERVER_PORT);
450 dst.sin6_addr = in6addr_all_dhcp_relay_agents_and_servers_mc;
452 control_buf_len = CMSG_SPACE(sizeof(struct in6_pktinfo));
453 control_buf = g_try_malloc0(control_buf_len);
454 if (control_buf == NULL) {
459 memset(&m, 0, sizeof(m));
460 memset(&v, 0, sizeof(v));
463 m.msg_namelen = sizeof(dst);
465 v.iov_base = (char *)dhcp_pkt;
470 m.msg_control = control_buf;
471 m.msg_controllen = control_buf_len;
472 cmsg = CMSG_FIRSTHDR(&m);
473 cmsg->cmsg_level = IPPROTO_IPV6;
474 cmsg->cmsg_type = IPV6_PKTINFO;
475 cmsg->cmsg_len = CMSG_LEN(sizeof(*pktinfo));
477 pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmsg);
478 memset(pktinfo, 0, sizeof(*pktinfo));
479 pktinfo->ipi6_ifindex = index;
480 m.msg_controllen = cmsg->cmsg_len;
482 ret = sendmsg(fd, &m, 0);
484 perror("DHCPv6 msg send failed");
492 int dhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
493 uint32_t source_ip, int source_port, uint32_t dest_ip,
494 int dest_port, const uint8_t *dest_arp, int ifindex)
496 struct sockaddr_ll dest;
497 struct ip_udp_dhcp_packet packet;
501 IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) -
502 EXTEND_FOR_BUGGY_SERVERS,
503 UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE -
504 offsetof(struct ip_udp_dhcp_packet, udp),
507 fd = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IP));
511 memset(&dest, 0, sizeof(dest));
512 memset(&packet, 0, sizeof(packet));
513 packet.data = *dhcp_pkt;
515 dest.sll_family = AF_PACKET;
516 dest.sll_protocol = htons(ETH_P_IP);
517 dest.sll_ifindex = ifindex;
519 memcpy(dest.sll_addr, dest_arp, 6);
520 if (bind(fd, (struct sockaddr *)&dest, sizeof(dest)) < 0) {
525 packet.ip.protocol = IPPROTO_UDP;
526 packet.ip.saddr = source_ip;
527 packet.ip.daddr = dest_ip;
528 packet.udp.source = htons(source_port);
529 packet.udp.dest = htons(dest_port);
530 /* size, excluding IP header: */
531 packet.udp.len = htons(UPD_DHCP_SIZE);
532 /* for UDP checksumming, ip.len is set to UDP packet len */
533 packet.ip.tot_len = packet.udp.len;
534 packet.udp.check = dhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
535 /* but for sending, it is set to IP packet len */
536 packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
537 packet.ip.ihl = sizeof(packet.ip) >> 2;
538 packet.ip.version = IPVERSION;
539 packet.ip.ttl = IPDEFTTL;
540 packet.ip.check = dhcp_checksum(&packet.ip, sizeof(packet.ip));
543 * Currently we send full-sized DHCP packets (zero padded).
544 * If you need to change this: last byte of the packet is
545 * packet.data.options[dhcp_end_option(packet.data.options)]
547 n = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
548 (struct sockaddr *) &dest, sizeof(dest));
557 int dhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
558 uint32_t source_ip, int source_port,
559 uint32_t dest_ip, int dest_port)
561 struct sockaddr_in client;
565 DHCP_SIZE = sizeof(struct dhcp_packet) -
566 EXTEND_FOR_BUGGY_SERVERS,
569 fd = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
573 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
575 memset(&client, 0, sizeof(client));
576 client.sin_family = AF_INET;
577 client.sin_port = htons(source_port);
578 client.sin_addr.s_addr = source_ip;
579 if (bind(fd, (struct sockaddr *) &client, sizeof(client)) < 0) {
584 memset(&client, 0, sizeof(client));
585 client.sin_family = AF_INET;
586 client.sin_port = htons(dest_port);
587 client.sin_addr.s_addr = dest_ip;
588 if (connect(fd, (struct sockaddr *) &client, sizeof(client)) < 0) {
593 n = write(fd, dhcp_pkt, DHCP_SIZE);
603 int dhcp_l3_socket(int port, const char *interface, int family)
605 int fd, opt = 1, len;
606 struct sockaddr_in addr4;
607 struct sockaddr_in6 addr6;
608 struct sockaddr *addr;
610 fd = socket(family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
614 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
616 if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
617 interface, strlen(interface) + 1) < 0) {
622 if (family == AF_INET) {
623 memset(&addr4, 0, sizeof(addr4));
624 addr4.sin_family = family;
625 addr4.sin_port = htons(port);
626 addr = (struct sockaddr *)&addr4;
628 } else if (family == AF_INET6) {
629 memset(&addr6, 0, sizeof(addr6));
630 addr6.sin6_family = family;
631 addr6.sin6_port = htons(port);
632 addr = (struct sockaddr *)&addr6;
639 if (bind(fd, addr, len) != 0) {
647 char *get_interface_name(int index)
655 sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
657 perror("Open socket error");
661 memset(&ifr, 0, sizeof(ifr));
662 ifr.ifr_ifindex = index;
664 err = ioctl(sk, SIOCGIFNAME, &ifr);
666 perror("Get interface name error");
673 return g_strdup(ifr.ifr_name);
676 gboolean interface_is_up(int index)
680 gboolean ret = FALSE;
682 sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
684 perror("Open socket error");
688 memset(&ifr, 0, sizeof(ifr));
689 ifr.ifr_ifindex = index;
691 err = ioctl(sk, SIOCGIFNAME, &ifr);
693 perror("Get interface name error");
697 err = ioctl(sk, SIOCGIFFLAGS, &ifr);
699 perror("Get interface flags error");
703 if (ifr.ifr_flags & IFF_UP)