2 * DHCP library with GLib integration
4 * Copyright (C) 2007-2013 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) {
174 *option_len = opt_len;
175 found = optionptr + 2 + 2;
186 *option_count = count;
198 uint8_t *dhcpv6_get_sub_option(unsigned char *option, uint16_t max_len,
199 uint16_t *option_code, uint16_t *option_len)
204 rem = max_len - 2 - 2;
210 code = option[0] << 8 | option[1];
211 len = option[2] << 8 | option[3];
224 * Add an option (supplied in binary form) to the options.
225 * Option format: [code][len][data1][data2]..[dataLEN]
227 void dhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt)
230 uint8_t *optionptr = packet->options;
231 unsigned end = dhcp_end_option(optionptr);
233 len = OPT_DATA + addopt[OPT_LEN];
235 /* end position + (option code/length + addopt length) + end option */
236 if (end + len + 1 >= DHCP_OPTIONS_BUFSIZE)
237 /* option did not fit into the packet */
240 memcpy(optionptr + end, addopt, len);
242 optionptr[end + len] = DHCP_END;
246 * Add an option (supplied in binary form) to the options.
247 * Option format: [code][len][data1][data2]..[dataLEN]
249 void dhcpv6_add_binary_option(struct dhcpv6_packet *packet, uint16_t max_len,
250 uint16_t *pkt_len, uint8_t *addopt)
253 uint8_t *optionptr = packet->options;
255 len = 2 + 2 + (addopt[2] << 8 | addopt[3]);
257 /* end position + (option code/length + addopt length) */
258 if (*pkt_len + len >= max_len)
259 /* option did not fit into the packet */
262 memcpy(optionptr + *pkt_len, addopt, len);
266 static GDHCPOptionType check_option(uint8_t code, uint8_t data_len)
268 GDHCPOptionType type = dhcp_get_code_type(code);
271 if (type == OPTION_UNKNOWN)
274 len = dhcp_option_lengths[type & OPTION_TYPE_MASK];
275 if (len != data_len) {
276 printf("Invalid option len %d (expecting %d) for code 0x%x\n",
277 data_len, len, code);
278 return OPTION_UNKNOWN;
284 void dhcp_add_option_uint32(struct dhcp_packet *packet, uint8_t code,
289 if (check_option(code, sizeof(data)) == OPTION_UNKNOWN)
292 option[OPT_CODE] = code;
293 option[OPT_LEN] = sizeof(data);
294 put_be32(data, option + OPT_DATA);
296 dhcp_add_binary_option(packet, option);
301 void dhcp_add_option_uint16(struct dhcp_packet *packet, uint8_t code,
306 if (check_option(code, sizeof(data)) == OPTION_UNKNOWN)
309 option[OPT_CODE] = code;
310 option[OPT_LEN] = sizeof(data);
311 put_be16(data, option + OPT_DATA);
313 dhcp_add_binary_option(packet, option);
318 void dhcp_add_option_uint8(struct dhcp_packet *packet, uint8_t code,
323 if (check_option(code, sizeof(data)) == OPTION_UNKNOWN)
326 option[OPT_CODE] = code;
327 option[OPT_LEN] = sizeof(data);
328 option[OPT_DATA] = data;
330 dhcp_add_binary_option(packet, option);
335 void dhcp_init_header(struct dhcp_packet *packet, char type)
337 memset(packet, 0, sizeof(*packet));
339 packet->op = BOOTREQUEST;
345 packet->op = BOOTREPLY;
350 packet->cookie = htonl(DHCP_MAGIC);
351 packet->options[0] = DHCP_END;
353 dhcp_add_option_uint8(packet, DHCP_MESSAGE_TYPE, type);
356 void dhcpv6_init_header(struct dhcpv6_packet *packet, uint8_t type)
360 memset(packet, 0, sizeof(*packet));
362 packet->message = type;
366 packet->transaction_id[0] = (id >> 16) & 0xff;
367 packet->transaction_id[1] = (id >> 8) & 0xff;
368 packet->transaction_id[2] = id & 0xff;
371 int dhcp_recv_l3_packet(struct dhcp_packet *packet, int fd)
375 memset(packet, 0, sizeof(*packet));
377 n = read(fd, packet, sizeof(*packet));
381 if (packet->cookie != htonl(DHCP_MAGIC))
387 int dhcpv6_recv_l3_packet(struct dhcpv6_packet **packet, unsigned char *buf,
392 n = read(fd, buf, buf_len);
396 *packet = (struct dhcpv6_packet *)buf;
401 /* TODO: Use glib checksum */
402 uint16_t dhcp_checksum(void *addr, int count)
405 * Compute Internet Checksum for "count" bytes
406 * beginning at location "addr".
409 uint16_t *source = (uint16_t *) addr;
412 /* This is the inner loop */
417 /* Add left-over byte, if any */
419 /* Make sure that the left-over byte is added correctly both
420 * with little and big endian hosts */
422 *(uint8_t *) &tmp = *(uint8_t *) source;
425 /* Fold 32-bit sum to 16 bits */
427 sum = (sum & 0xffff) + (sum >> 16);
432 #define IN6ADDR_ALL_DHCP_RELAY_AGENTS_AND_SERVERS_MC_INIT \
433 { { { 0xff,0x02,0,0,0,0,0,0,0,0,0,0,0,0x1,0,0x2 } } } /* ff02::1:2 */
434 static const struct in6_addr in6addr_all_dhcp_relay_agents_and_servers_mc =
435 IN6ADDR_ALL_DHCP_RELAY_AGENTS_AND_SERVERS_MC_INIT;
437 /* from netinet/in.h */
439 struct in6_addr ipi6_addr; /* src/dst IPv6 address */
440 unsigned int ipi6_ifindex; /* send/recv interface index */
443 int dhcpv6_send_packet(int index, struct dhcpv6_packet *dhcp_pkt, int len)
447 struct in6_pktinfo *pktinfo;
448 struct cmsghdr *cmsg;
450 struct sockaddr_in6 dst;
452 size_t control_buf_len;
454 fd = socket(PF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
458 memset(&dst, 0, sizeof(dst));
459 dst.sin6_family = AF_INET6;
460 dst.sin6_port = htons(DHCPV6_SERVER_PORT);
462 dst.sin6_addr = in6addr_all_dhcp_relay_agents_and_servers_mc;
464 control_buf_len = CMSG_SPACE(sizeof(struct in6_pktinfo));
465 control_buf = g_try_malloc0(control_buf_len);
471 memset(&m, 0, sizeof(m));
472 memset(&v, 0, sizeof(v));
475 m.msg_namelen = sizeof(dst);
477 v.iov_base = (char *)dhcp_pkt;
482 m.msg_control = control_buf;
483 m.msg_controllen = control_buf_len;
484 cmsg = CMSG_FIRSTHDR(&m);
485 cmsg->cmsg_level = IPPROTO_IPV6;
486 cmsg->cmsg_type = IPV6_PKTINFO;
487 cmsg->cmsg_len = CMSG_LEN(sizeof(*pktinfo));
489 pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmsg);
490 memset(pktinfo, 0, sizeof(*pktinfo));
491 pktinfo->ipi6_ifindex = index;
492 m.msg_controllen = cmsg->cmsg_len;
494 ret = sendmsg(fd, &m, 0);
496 char *msg = "DHCPv6 msg send failed";
498 if (errno == EADDRNOTAVAIL) {
499 char *str = g_strdup_printf("%s (index %d)",
513 int dhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
514 uint32_t source_ip, int source_port,
515 uint32_t dest_ip, int dest_port,
516 const uint8_t *dest_arp, int ifindex, bool bcast)
518 struct sockaddr_ll dest;
519 struct ip_udp_dhcp_packet packet;
523 IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) -
524 EXTEND_FOR_BUGGY_SERVERS,
525 UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE -
526 offsetof(struct ip_udp_dhcp_packet, udp),
529 fd = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IP));
534 dhcp_pkt->flags |= htons(BROADCAST_FLAG);
536 memset(&dest, 0, sizeof(dest));
537 memset(&packet, 0, sizeof(packet));
538 packet.data = *dhcp_pkt;
540 dest.sll_family = AF_PACKET;
541 dest.sll_protocol = htons(ETH_P_IP);
542 dest.sll_ifindex = ifindex;
544 memcpy(dest.sll_addr, dest_arp, 6);
545 if (bind(fd, (struct sockaddr *)&dest, sizeof(dest)) < 0) {
550 packet.ip.protocol = IPPROTO_UDP;
551 packet.ip.saddr = source_ip;
552 packet.ip.daddr = dest_ip;
553 packet.udp.source = htons(source_port);
554 packet.udp.dest = htons(dest_port);
555 /* size, excluding IP header: */
556 packet.udp.len = htons(UPD_DHCP_SIZE);
557 /* for UDP checksumming, ip.len is set to UDP packet len */
558 packet.ip.tot_len = packet.udp.len;
559 packet.udp.check = dhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
560 /* but for sending, it is set to IP packet len */
561 packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
562 packet.ip.ihl = sizeof(packet.ip) >> 2;
563 packet.ip.version = IPVERSION;
564 packet.ip.ttl = IPDEFTTL;
565 packet.ip.check = dhcp_checksum(&packet.ip, sizeof(packet.ip));
568 * Currently we send full-sized DHCP packets (zero padded).
569 * If you need to change this: last byte of the packet is
570 * packet.data.options[dhcp_end_option(packet.data.options)]
572 n = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
573 (struct sockaddr *) &dest, sizeof(dest));
582 int dhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
583 uint32_t source_ip, int source_port,
584 uint32_t dest_ip, int dest_port)
586 struct sockaddr_in client;
590 DHCP_SIZE = sizeof(struct dhcp_packet) -
591 EXTEND_FOR_BUGGY_SERVERS,
594 fd = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
598 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
600 memset(&client, 0, sizeof(client));
601 client.sin_family = AF_INET;
602 client.sin_port = htons(source_port);
603 client.sin_addr.s_addr = htonl(source_ip);
604 if (bind(fd, (struct sockaddr *) &client, sizeof(client)) < 0) {
609 memset(&client, 0, sizeof(client));
610 client.sin_family = AF_INET;
611 client.sin_port = htons(dest_port);
612 client.sin_addr.s_addr = htonl(dest_ip);
613 if (connect(fd, (struct sockaddr *) &client, sizeof(client)) < 0) {
618 n = write(fd, dhcp_pkt, DHCP_SIZE);
628 int dhcp_l3_socket(int port, const char *interface, int family)
630 int fd, opt = 1, len;
631 struct sockaddr_in addr4;
632 struct sockaddr_in6 addr6;
633 struct sockaddr *addr;
635 fd = socket(family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
639 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
641 if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
642 interface, strlen(interface) + 1) < 0) {
647 if (family == AF_INET) {
648 memset(&addr4, 0, sizeof(addr4));
649 addr4.sin_family = family;
650 addr4.sin_port = htons(port);
651 addr = (struct sockaddr *)&addr4;
653 } else if (family == AF_INET6) {
654 memset(&addr6, 0, sizeof(addr6));
655 addr6.sin6_family = family;
656 addr6.sin6_port = htons(port);
657 addr = (struct sockaddr *)&addr6;
664 if (bind(fd, addr, len) != 0) {
672 char *get_interface_name(int index)
680 sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
682 perror("Open socket error");
686 memset(&ifr, 0, sizeof(ifr));
687 ifr.ifr_ifindex = index;
689 err = ioctl(sk, SIOCGIFNAME, &ifr);
691 perror("Get interface name error");
698 return g_strdup(ifr.ifr_name);
701 bool interface_is_up(int index)
707 sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
709 perror("Open socket error");
713 memset(&ifr, 0, sizeof(ifr));
714 ifr.ifr_ifindex = index;
716 err = ioctl(sk, SIOCGIFNAME, &ifr);
718 perror("Get interface name error");
722 err = ioctl(sk, SIOCGIFFLAGS, &ifr);
724 perror("Get interface flags error");
728 if (ifr.ifr_flags & IFF_UP)