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 /* get a rough idea of how long an option will be */
148 static const uint8_t len_of_option_as_string[] = {
149 [OPTION_IP] = sizeof("255.255.255.255 "),
151 [OPTION_U8] = sizeof("255 "),
152 [OPTION_U16] = sizeof("65535 "),
153 [OPTION_U32] = sizeof("4294967295 "),
156 static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
158 return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
161 /* Create "opt_value1 option_value2 ..." string */
162 char *malloc_option_value_string(uint8_t *option, GDHCPOptionType type)
164 unsigned upper_length;
168 len = option[OPT_LEN - OPT_DATA];
169 type &= OPTION_TYPE_MASK;
170 optlen = dhcp_option_lengths[type];
173 upper_length = len_of_option_as_string[type] *
174 ((unsigned)len / (unsigned)optlen);
175 dest = ret = g_malloc(upper_length + 1);
179 while (len >= optlen) {
182 dest += sprint_nip(dest, "", option);
185 uint16_t val_u16 = get_be16(option);
186 dest += sprintf(dest, "%u", val_u16);
190 uint32_t val_u32 = get_be32(option);
191 dest += sprintf(dest, "%u", val_u32);
195 memcpy(dest, option, len);
212 uint8_t *dhcpv6_get_option(struct dhcpv6_packet *packet, uint16_t pkt_len,
213 int code, uint16_t *option_len, int *option_count)
216 uint8_t *optionptr, *found = NULL;
217 uint16_t opt_code, opt_len, len;
219 optionptr = packet->options;
220 rem = pkt_len - 1 - 3;
226 opt_code = optionptr[0] << 8 | optionptr[1];
227 opt_len = len = optionptr[2] << 8 | optionptr[3];
228 len += 2 + 2; /* skip code and len */
237 if (opt_code == code) {
238 if (option_len != NULL)
239 *option_len = opt_len;
243 found = optionptr + 2 + 2;
253 if (option_count != NULL)
254 *option_count = count;
259 if (option_len != NULL)
261 if (option_count != NULL)
266 uint8_t *dhcpv6_get_sub_option(unsigned char *option, uint16_t max_len,
267 uint16_t *option_code, uint16_t *option_len)
272 rem = max_len - 2 - 2;
278 code = option[0] << 8 | option[1];
279 len = option[2] << 8 | option[3];
292 * Add an option (supplied in binary form) to the options.
293 * Option format: [code][len][data1][data2]..[dataLEN]
295 void dhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt)
298 uint8_t *optionptr = packet->options;
299 unsigned end = dhcp_end_option(optionptr);
301 len = OPT_DATA + addopt[OPT_LEN];
303 /* end position + (option code/length + addopt length) + end option */
304 if (end + len + 1 >= DHCP_OPTIONS_BUFSIZE)
305 /* option did not fit into the packet */
308 memcpy(optionptr + end, addopt, len);
310 optionptr[end + len] = DHCP_END;
314 * Add an option (supplied in binary form) to the options.
315 * Option format: [code][len][data1][data2]..[dataLEN]
317 void dhcpv6_add_binary_option(struct dhcpv6_packet *packet, uint16_t max_len,
318 uint16_t *pkt_len, uint8_t *addopt)
321 uint8_t *optionptr = packet->options;
323 len = 2 + 2 + (addopt[2] << 8 | addopt[3]);
325 /* end position + (option code/length + addopt length) */
326 if (*pkt_len + len >= max_len)
327 /* option did not fit into the packet */
330 memcpy(optionptr + *pkt_len, addopt, len);
334 static GDHCPOptionType check_option(uint8_t code, uint8_t data_len)
336 GDHCPOptionType type = dhcp_get_code_type(code);
339 if (type == OPTION_UNKNOWN)
342 len = dhcp_option_lengths[type & OPTION_TYPE_MASK];
343 if (len != data_len) {
344 printf("Invalid option len %d (expecting %d) for code 0x%x\n",
345 data_len, len, code);
346 return OPTION_UNKNOWN;
352 void dhcp_add_option_uint32(struct dhcp_packet *packet, uint8_t code,
357 if (check_option(code, sizeof(data)) == OPTION_UNKNOWN)
360 option[OPT_CODE] = code;
361 option[OPT_LEN] = sizeof(data);
362 put_be32(data, option + OPT_DATA);
364 dhcp_add_binary_option(packet, option);
369 void dhcp_add_option_uint16(struct dhcp_packet *packet, uint8_t code,
374 if (check_option(code, sizeof(data)) == OPTION_UNKNOWN)
377 option[OPT_CODE] = code;
378 option[OPT_LEN] = sizeof(data);
379 put_be16(data, option + OPT_DATA);
381 dhcp_add_binary_option(packet, option);
386 void dhcp_add_option_uint8(struct dhcp_packet *packet, uint8_t code,
391 if (check_option(code, sizeof(data)) == OPTION_UNKNOWN)
394 option[OPT_CODE] = code;
395 option[OPT_LEN] = sizeof(data);
396 option[OPT_DATA] = data;
398 dhcp_add_binary_option(packet, option);
403 void dhcp_init_header(struct dhcp_packet *packet, char type)
405 memset(packet, 0, sizeof(*packet));
407 packet->op = BOOTREQUEST;
413 packet->op = BOOTREPLY;
418 packet->cookie = htonl(DHCP_MAGIC);
419 packet->options[0] = DHCP_END;
421 dhcp_add_option_uint8(packet, DHCP_MESSAGE_TYPE, type);
424 void dhcpv6_init_header(struct dhcpv6_packet *packet, uint8_t type)
428 memset(packet, 0, sizeof(*packet));
430 packet->message = type;
434 packet->transaction_id[0] = (id >> 16) & 0xff;
435 packet->transaction_id[1] = (id >> 8) & 0xff;
436 packet->transaction_id[2] = id & 0xff;
439 static gboolean check_vendor(uint8_t *option_vendor, const char *vendor)
441 uint8_t vendor_length = sizeof(vendor) - 1;
443 if (option_vendor[OPT_LEN - OPT_DATA] != vendor_length)
446 if (memcmp(option_vendor, vendor, vendor_length) != 0)
452 static void check_broken_vendor(struct dhcp_packet *packet)
456 if (packet->op != BOOTREQUEST)
459 vendor = dhcp_get_option(packet, DHCP_VENDOR);
463 if (check_vendor(vendor, "MSFT 98") == TRUE)
464 packet->flags |= htons(BROADCAST_FLAG);
467 int dhcp_recv_l3_packet(struct dhcp_packet *packet, int fd)
471 memset(packet, 0, sizeof(*packet));
473 n = read(fd, packet, sizeof(*packet));
477 if (packet->cookie != htonl(DHCP_MAGIC))
480 check_broken_vendor(packet);
485 int dhcpv6_recv_l3_packet(struct dhcpv6_packet **packet, unsigned char *buf,
490 n = read(fd, buf, buf_len);
494 *packet = (struct dhcpv6_packet *)buf;
499 /* TODO: Use glib checksum */
500 uint16_t dhcp_checksum(void *addr, int count)
503 * Compute Internet Checksum for "count" bytes
504 * beginning at location "addr".
507 uint16_t *source = (uint16_t *) addr;
510 /* This is the inner loop */
515 /* Add left-over byte, if any */
517 /* Make sure that the left-over byte is added correctly both
518 * with little and big endian hosts */
520 *(uint8_t *) &tmp = *(uint8_t *) source;
523 /* Fold 32-bit sum to 16 bits */
525 sum = (sum & 0xffff) + (sum >> 16);
530 #define IN6ADDR_ALL_DHCP_RELAY_AGENTS_AND_SERVERS_MC_INIT \
531 { { { 0xff,0x02,0,0,0,0,0,0,0,0,0,0,0,0x1,0,0x2 } } } /* ff02::1:2 */
532 static const struct in6_addr in6addr_all_dhcp_relay_agents_and_servers_mc =
533 IN6ADDR_ALL_DHCP_RELAY_AGENTS_AND_SERVERS_MC_INIT;
535 /* from netinet/in.h */
537 struct in6_addr ipi6_addr; /* src/dst IPv6 address */
538 unsigned int ipi6_ifindex; /* send/recv interface index */
541 int dhcpv6_send_packet(int index, struct dhcpv6_packet *dhcp_pkt, int len)
545 struct in6_pktinfo *pktinfo;
546 struct cmsghdr *cmsg;
548 struct sockaddr_in6 dst;
550 size_t control_buf_len;
552 fd = socket(PF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
556 memset(&dst, 0, sizeof(dst));
557 dst.sin6_family = AF_INET6;
558 dst.sin6_port = htons(DHCPV6_SERVER_PORT);
560 dst.sin6_addr = in6addr_all_dhcp_relay_agents_and_servers_mc;
562 control_buf_len = CMSG_SPACE(sizeof(struct in6_pktinfo));
563 control_buf = g_try_malloc0(control_buf_len);
564 if (control_buf == NULL) {
569 memset(&m, 0, sizeof(m));
570 memset(&v, 0, sizeof(v));
573 m.msg_namelen = sizeof(dst);
575 v.iov_base = (char *)dhcp_pkt;
580 m.msg_control = control_buf;
581 m.msg_controllen = control_buf_len;
582 cmsg = CMSG_FIRSTHDR(&m);
583 cmsg->cmsg_level = IPPROTO_IPV6;
584 cmsg->cmsg_type = IPV6_PKTINFO;
585 cmsg->cmsg_len = CMSG_LEN(sizeof(*pktinfo));
587 pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmsg);
588 memset(pktinfo, 0, sizeof(*pktinfo));
589 pktinfo->ipi6_ifindex = index;
590 m.msg_controllen = cmsg->cmsg_len;
592 ret = sendmsg(fd, &m, 0);
594 perror("DHCPv6 msg send failed");
602 int dhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
603 uint32_t source_ip, int source_port, uint32_t dest_ip,
604 int dest_port, const uint8_t *dest_arp, int ifindex)
606 struct sockaddr_ll dest;
607 struct ip_udp_dhcp_packet packet;
611 IP_UPD_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) -
612 EXTEND_FOR_BUGGY_SERVERS,
613 UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE -
614 offsetof(struct ip_udp_dhcp_packet, udp),
617 fd = socket(PF_PACKET, SOCK_DGRAM | SOCK_CLOEXEC, htons(ETH_P_IP));
621 memset(&dest, 0, sizeof(dest));
622 memset(&packet, 0, sizeof(packet));
623 packet.data = *dhcp_pkt;
625 dest.sll_family = AF_PACKET;
626 dest.sll_protocol = htons(ETH_P_IP);
627 dest.sll_ifindex = ifindex;
629 memcpy(dest.sll_addr, dest_arp, 6);
630 if (bind(fd, (struct sockaddr *)&dest, sizeof(dest)) < 0) {
635 packet.ip.protocol = IPPROTO_UDP;
636 packet.ip.saddr = source_ip;
637 packet.ip.daddr = dest_ip;
638 packet.udp.source = htons(source_port);
639 packet.udp.dest = htons(dest_port);
640 /* size, excluding IP header: */
641 packet.udp.len = htons(UPD_DHCP_SIZE);
642 /* for UDP checksumming, ip.len is set to UDP packet len */
643 packet.ip.tot_len = packet.udp.len;
644 packet.udp.check = dhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
645 /* but for sending, it is set to IP packet len */
646 packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
647 packet.ip.ihl = sizeof(packet.ip) >> 2;
648 packet.ip.version = IPVERSION;
649 packet.ip.ttl = IPDEFTTL;
650 packet.ip.check = dhcp_checksum(&packet.ip, sizeof(packet.ip));
653 * Currently we send full-sized DHCP packets (zero padded).
654 * If you need to change this: last byte of the packet is
655 * packet.data.options[dhcp_end_option(packet.data.options)]
657 n = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
658 (struct sockaddr *) &dest, sizeof(dest));
667 int dhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
668 uint32_t source_ip, int source_port,
669 uint32_t dest_ip, int dest_port)
671 struct sockaddr_in client;
675 DHCP_SIZE = sizeof(struct dhcp_packet) -
676 EXTEND_FOR_BUGGY_SERVERS,
679 fd = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
683 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
685 memset(&client, 0, sizeof(client));
686 client.sin_family = AF_INET;
687 client.sin_port = htons(source_port);
688 client.sin_addr.s_addr = htonl(source_ip);
689 if (bind(fd, (struct sockaddr *) &client, sizeof(client)) < 0) {
694 memset(&client, 0, sizeof(client));
695 client.sin_family = AF_INET;
696 client.sin_port = htons(dest_port);
697 client.sin_addr.s_addr = htonl(dest_ip);
698 if (connect(fd, (struct sockaddr *) &client, sizeof(client)) < 0) {
703 n = write(fd, dhcp_pkt, DHCP_SIZE);
713 int dhcp_l3_socket(int port, const char *interface, int family)
715 int fd, opt = 1, len;
716 struct sockaddr_in addr4;
717 struct sockaddr_in6 addr6;
718 struct sockaddr *addr;
720 fd = socket(family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
724 setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
726 if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE,
727 interface, strlen(interface) + 1) < 0) {
732 if (family == AF_INET) {
733 memset(&addr4, 0, sizeof(addr4));
734 addr4.sin_family = family;
735 addr4.sin_port = htons(port);
736 addr = (struct sockaddr *)&addr4;
738 } else if (family == AF_INET6) {
739 memset(&addr6, 0, sizeof(addr6));
740 addr6.sin6_family = family;
741 addr6.sin6_port = htons(port);
742 addr = (struct sockaddr *)&addr6;
749 if (bind(fd, addr, len) != 0) {
757 char *get_interface_name(int index)
765 sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
767 perror("Open socket error");
771 memset(&ifr, 0, sizeof(ifr));
772 ifr.ifr_ifindex = index;
774 err = ioctl(sk, SIOCGIFNAME, &ifr);
776 perror("Get interface name error");
783 return g_strdup(ifr.ifr_name);
786 gboolean interface_is_up(int index)
790 gboolean ret = FALSE;
792 sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
794 perror("Open socket error");
798 memset(&ifr, 0, sizeof(ifr));
799 ifr.ifr_ifindex = index;
801 err = ioctl(sk, SIOCGIFNAME, &ifr);
803 perror("Get interface name error");
807 err = ioctl(sk, SIOCGIFFLAGS, &ifr);
809 perror("Get interface flags error");
813 if (ifr.ifr_flags & IFF_UP)