1 /* vi: set sw=4 ts=4: */
3 #include <netinet/in.h>
4 #if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION
5 #include <netpacket/packet.h>
6 #include <net/ethernet.h>
9 #include <linux/if_packet.h>
10 #include <linux/if_ether.h>
18 void udhcp_init_header(struct dhcpMessage *packet, char type)
20 memset(packet, 0, sizeof(struct dhcpMessage));
26 packet->op = BOOTREQUEST;
31 packet->op = BOOTREPLY;
33 packet->htype = ETH_10MB;
34 packet->hlen = ETH_10MB_LEN;
35 packet->cookie = htonl(DHCP_MAGIC);
36 packet->options[0] = DHCP_END;
37 add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
41 /* read a packet from socket fd, return -1 on read error, -2 on packet error */
42 int udhcp_recv_packet(struct dhcpMessage *packet, int fd)
45 unsigned char *vendor;
47 memset(packet, 0, sizeof(*packet));
48 bytes = safe_read(fd, packet, sizeof(*packet));
50 DEBUG("cannot read on listening socket, ignoring");
51 return bytes; /* returns -1 */
54 if (packet->cookie != htonl(DHCP_MAGIC)) {
55 bb_error_msg("received bogus message, ignoring");
58 DEBUG("Received a packet");
60 if (packet->op == BOOTREQUEST) {
61 vendor = get_option(packet, DHCP_VENDOR);
64 static const char broken_vendors[][8] = {
69 for (i = 0; broken_vendors[i][0]; i++) {
70 if (vendor[OPT_LEN - 2] == (uint8_t)strlen(broken_vendors[i])
71 && !strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - 2])
73 DEBUG("broken client (%s), forcing broadcast",
75 packet->flags |= htons(BROADCAST_FLAG);
79 if (vendor[OPT_LEN - 2] == (uint8_t)(sizeof("MSFT 98")-1)
80 && memcmp(vendor, "MSFT 98", sizeof("MSFT 98")-1) == 0
82 DEBUG("broken client (%s), forcing broadcast", "MSFT 98");
83 packet->flags |= htons(BROADCAST_FLAG);
93 uint16_t udhcp_checksum(void *addr, int count)
95 /* Compute Internet Checksum for "count" bytes
96 * beginning at location "addr".
99 uint16_t *source = (uint16_t *) addr;
102 /* This is the inner loop */
107 /* Add left-over byte, if any */
109 /* Make sure that the left-over byte is added correctly both
110 * with little and big endian hosts */
112 *(uint8_t*)&tmp = *(uint8_t*)source;
115 /* Fold 32-bit sum to 16 bits */
117 sum = (sum & 0xffff) + (sum >> 16);
123 /* Construct a ip/udp header for a packet, send packet */
124 int udhcp_send_raw_packet(struct dhcpMessage *payload,
125 uint32_t source_ip, int source_port,
126 uint32_t dest_ip, int dest_port, const uint8_t *dest_arp, int ifindex)
128 struct sockaddr_ll dest;
129 struct udp_dhcp_packet packet;
135 IP_UPD_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
136 UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE - offsetof(struct udp_dhcp_packet, udp),
139 fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
145 memset(&dest, 0, sizeof(dest));
146 memset(&packet, 0, sizeof(packet));
147 packet.data = *payload; /* struct copy */
149 dest.sll_family = AF_PACKET;
150 dest.sll_protocol = htons(ETH_P_IP);
151 dest.sll_ifindex = ifindex;
153 memcpy(dest.sll_addr, dest_arp, 6);
154 if (bind(fd, (struct sockaddr *)&dest, sizeof(dest)) < 0) {
159 packet.ip.protocol = IPPROTO_UDP;
160 packet.ip.saddr = source_ip;
161 packet.ip.daddr = dest_ip;
162 packet.udp.source = htons(source_port);
163 packet.udp.dest = htons(dest_port);
164 /* size, excluding IP header: */
165 packet.udp.len = htons(UPD_DHCP_SIZE);
166 /* for UDP checksumming, ip.len is set to UDP packet len */
167 packet.ip.tot_len = packet.udp.len;
168 packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
169 /* but for sending, it is set to IP packet len */
170 packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
171 packet.ip.ihl = sizeof(packet.ip) >> 2;
172 packet.ip.version = IPVERSION;
173 packet.ip.ttl = IPDEFTTL;
174 packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
176 /* Currently we send full-sized DHCP packets (zero padded).
177 * If you need to change this: last byte of the packet is
178 * packet.data.options[end_option(packet.data.options)]
180 result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
181 (struct sockaddr *) &dest, sizeof(dest));
187 bb_perror_msg(msg, "PACKET");
193 /* Let the kernel do all the work for packet generation */
194 int udhcp_send_kernel_packet(struct dhcpMessage *payload,
195 uint32_t source_ip, int source_port,
196 uint32_t dest_ip, int dest_port)
198 struct sockaddr_in client;
204 DHCP_SIZE = sizeof(struct dhcpMessage) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
207 fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
212 setsockopt_reuseaddr(fd);
214 memset(&client, 0, sizeof(client));
215 client.sin_family = AF_INET;
216 client.sin_port = htons(source_port);
217 client.sin_addr.s_addr = source_ip;
218 if (bind(fd, (struct sockaddr *)&client, sizeof(client)) == -1) {
223 memset(&client, 0, sizeof(client));
224 client.sin_family = AF_INET;
225 client.sin_port = htons(dest_port);
226 client.sin_addr.s_addr = dest_ip;
227 if (connect(fd, (struct sockaddr *)&client, sizeof(client)) == -1) {
232 /* Currently we send full-sized DHCP packets (see above) */
233 result = safe_write(fd, payload, DHCP_SIZE);
239 bb_perror_msg(msg, "UDP");