1 /* vi: set sw=4 ts=4: */
5 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
7 * Licensed under GPLv2, see file LICENSE in this source tree.
11 #include <netinet/in.h>
12 #include <netinet/if_ether.h>
13 #include <netpacket/packet.h>
15 void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type)
17 memset(packet, 0, sizeof(*packet));
18 packet->op = BOOTREQUEST; /* if client to a server */
23 packet->op = BOOTREPLY; /* if server to client */
25 packet->htype = 1; /* ethernet */
27 packet->cookie = htonl(DHCP_MAGIC);
29 packet->options[0] = DHCP_END;
30 udhcp_add_simple_option(packet, DHCP_MESSAGE_TYPE, type);
33 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
34 void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet)
36 char buf[sizeof(packet->chaddr)*2 + 1];
69 //, packet->chaddr[16]
75 *bin2hex(buf, (void *) packet->chaddr, sizeof(packet->chaddr)) = '\0';
76 bb_info_msg(" chaddr %s", buf);
80 /* Read a packet from socket fd, return -1 on read error, -2 on packet error */
81 int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd)
84 unsigned char *vendor;
86 memset(packet, 0, sizeof(*packet));
87 bytes = safe_read(fd, packet, sizeof(*packet));
89 log1("Packet read error, ignoring");
90 return bytes; /* returns -1 */
93 if (packet->cookie != htonl(DHCP_MAGIC)) {
94 bb_info_msg("Packet with bad magic, ignoring");
97 log1("Received a packet");
98 udhcp_dump_packet(packet);
100 if (packet->op == BOOTREQUEST) {
101 vendor = udhcp_get_option(packet, DHCP_VENDOR);
104 static const char broken_vendors[][8] = {
109 for (i = 0; broken_vendors[i][0]; i++) {
110 if (vendor[OPT_LEN - OPT_DATA] == (uint8_t)strlen(broken_vendors[i])
111 && strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - OPT_DATA]) == 0
113 log1("Broken client (%s), forcing broadcast replies",
115 packet->flags |= htons(BROADCAST_FLAG);
119 if (vendor[OPT_LEN - OPT_DATA] == (uint8_t)(sizeof("MSFT 98")-1)
120 && memcmp(vendor, "MSFT 98", sizeof("MSFT 98")-1) == 0
122 log1("Broken client (%s), forcing broadcast replies", "MSFT 98");
123 packet->flags |= htons(BROADCAST_FLAG);
132 /* Construct a ip/udp header for a packet, send packet */
133 int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
134 uint32_t source_nip, int source_port,
135 uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
138 struct sockaddr_ll dest_sll;
139 struct ip_udp_dhcp_packet packet;
145 fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
151 memset(&dest_sll, 0, sizeof(dest_sll));
152 memset(&packet, 0, offsetof(struct ip_udp_dhcp_packet, data));
153 packet.data = *dhcp_pkt; /* struct copy */
155 dest_sll.sll_family = AF_PACKET;
156 dest_sll.sll_protocol = htons(ETH_P_IP);
157 dest_sll.sll_ifindex = ifindex;
158 dest_sll.sll_halen = 6;
159 memcpy(dest_sll.sll_addr, dest_arp, 6);
161 if (bind(fd, (struct sockaddr *)&dest_sll, sizeof(dest_sll)) < 0) {
166 /* We were sending full-sized DHCP packets (zero padded),
167 * but some badly configured servers were seen dropping them.
168 * Apparently they drop all DHCP packets >576 *ethernet* octets big,
169 * whereas they may only drop packets >576 *IP* octets big
170 * (which for typical Ethernet II means 590 octets: 6+6+2 + 576).
172 * In order to work with those buggy servers,
173 * we truncate packets after end option byte.
175 padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options);
177 packet.ip.protocol = IPPROTO_UDP;
178 packet.ip.saddr = source_nip;
179 packet.ip.daddr = dest_nip;
180 packet.udp.source = htons(source_port);
181 packet.udp.dest = htons(dest_port);
182 /* size, excluding IP header: */
183 packet.udp.len = htons(UDP_DHCP_SIZE - padding);
184 /* for UDP checksumming, ip.len is set to UDP packet len */
185 packet.ip.tot_len = packet.udp.len;
186 packet.udp.check = inet_cksum((uint16_t *)&packet,
187 IP_UDP_DHCP_SIZE - padding);
188 /* but for sending, it is set to IP packet len */
189 packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding);
190 packet.ip.ihl = sizeof(packet.ip) >> 2;
191 packet.ip.version = IPVERSION;
192 packet.ip.ttl = IPDEFTTL;
193 packet.ip.check = inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip));
195 udhcp_dump_packet(dhcp_pkt);
196 result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,
197 (struct sockaddr *) &dest_sll, sizeof(dest_sll));
203 bb_perror_msg(msg, "PACKET");
208 /* Let the kernel do all the work for packet generation */
209 int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
210 uint32_t source_nip, int source_port,
211 uint32_t dest_nip, int dest_port)
213 struct sockaddr_in client;
219 fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
224 setsockopt_reuseaddr(fd);
226 memset(&client, 0, sizeof(client));
227 client.sin_family = AF_INET;
228 client.sin_port = htons(source_port);
229 client.sin_addr.s_addr = source_nip;
230 if (bind(fd, (struct sockaddr *)&client, sizeof(client)) == -1) {
235 memset(&client, 0, sizeof(client));
236 client.sin_family = AF_INET;
237 client.sin_port = htons(dest_port);
238 client.sin_addr.s_addr = dest_nip;
239 if (connect(fd, (struct sockaddr *)&client, sizeof(client)) == -1) {
244 udhcp_dump_packet(dhcp_pkt);
246 padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
247 result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
253 bb_perror_msg(msg, "UDP");