1 /* vi: set sw=4 ts=4: */
3 #include <netinet/in.h>
4 #if (__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_get_packet(struct dhcpMessage *packet, int fd)
44 static const char broken_vendors[][8] = {
50 char unsigned *vendor;
52 memset(packet, 0, sizeof(struct dhcpMessage));
53 bytes = read(fd, packet, sizeof(struct dhcpMessage));
55 DEBUG("cannot read on listening socket, ignoring");
59 if (ntohl(packet->cookie) != DHCP_MAGIC) {
60 bb_error_msg("received bogus message, ignoring");
63 DEBUG("Received a packet");
65 if (packet->op == BOOTREQUEST && (vendor = get_option(packet, DHCP_VENDOR))) {
66 for (i = 0; broken_vendors[i][0]; i++) {
67 if (vendor[OPT_LEN - 2] == (uint8_t)strlen(broken_vendors[i])
68 && !strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - 2])
70 DEBUG("broken client (%s), forcing broadcast",
72 packet->flags |= htons(BROADCAST_FLAG);
81 uint16_t udhcp_checksum(void *addr, int count)
83 /* Compute Internet Checksum for "count" bytes
84 * beginning at location "addr".
87 uint16_t *source = (uint16_t *) addr;
90 /* This is the inner loop */
95 /* Add left-over byte, if any */
97 /* Make sure that the left-over byte is added correctly both
98 * with little and big endian hosts */
100 *(uint8_t *) (&tmp) = * (uint8_t *) source;
103 /* Fold 32-bit sum to 16 bits */
105 sum = (sum & 0xffff) + (sum >> 16);
111 /* Construct a ip/udp header for a packet, and specify the source and dest hardware address */
112 void BUG_sizeof_struct_udp_dhcp_packet_must_be_576(void);
113 int udhcp_raw_packet(struct dhcpMessage *payload,
114 uint32_t source_ip, int source_port,
115 uint32_t dest_ip, int dest_port, uint8_t *dest_arp, int ifindex)
119 struct sockaddr_ll dest;
120 struct udp_dhcp_packet packet;
122 fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
124 bb_perror_msg("socket");
128 memset(&dest, 0, sizeof(dest));
129 memset(&packet, 0, sizeof(packet));
131 dest.sll_family = AF_PACKET;
132 dest.sll_protocol = htons(ETH_P_IP);
133 dest.sll_ifindex = ifindex;
135 memcpy(dest.sll_addr, dest_arp, 6);
136 if (bind(fd, (struct sockaddr *)&dest, sizeof(struct sockaddr_ll)) < 0) {
137 bb_perror_msg("bind");
142 packet.ip.protocol = IPPROTO_UDP;
143 packet.ip.saddr = source_ip;
144 packet.ip.daddr = dest_ip;
145 packet.udp.source = htons(source_port);
146 packet.udp.dest = htons(dest_port);
147 packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage)); /* cheat on the psuedo-header */
148 packet.ip.tot_len = packet.udp.len;
149 memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
150 packet.udp.check = udhcp_checksum(&packet, sizeof(struct udp_dhcp_packet));
152 packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
153 packet.ip.ihl = sizeof(packet.ip) >> 2;
154 packet.ip.version = IPVERSION;
155 packet.ip.ttl = IPDEFTTL;
156 packet.ip.check = udhcp_checksum(&(packet.ip), sizeof(packet.ip));
158 if (sizeof(struct udp_dhcp_packet) != 576)
159 BUG_sizeof_struct_udp_dhcp_packet_must_be_576();
161 result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0,
162 (struct sockaddr *) &dest, sizeof(dest));
164 bb_perror_msg("sendto");
171 /* Let the kernel do all the work for packet generation */
172 int udhcp_kernel_packet(struct dhcpMessage *payload,
173 uint32_t source_ip, int source_port,
174 uint32_t dest_ip, int dest_port)
177 struct sockaddr_in client;
179 fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
183 if (setsockopt_reuseaddr(fd) == -1) {
188 memset(&client, 0, sizeof(client));
189 client.sin_family = AF_INET;
190 client.sin_port = htons(source_port);
191 client.sin_addr.s_addr = source_ip;
193 if (bind(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1) {
198 memset(&client, 0, sizeof(client));
199 client.sin_family = AF_INET;
200 client.sin_port = htons(dest_port);
201 client.sin_addr.s_addr = dest_ip;
203 if (connect(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1) {
208 result = write(fd, payload, sizeof(struct dhcpMessage));