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)
85 memset(packet, 0, sizeof(*packet));
86 bytes = safe_read(fd, packet, sizeof(*packet));
88 log1("Packet read error, ignoring");
89 return bytes; /* returns -1 */
92 if (bytes < offsetof(struct dhcp_packet, options)
93 || packet->cookie != htonl(DHCP_MAGIC)
95 bb_info_msg("Packet with bad magic, ignoring");
98 log1("Received a packet");
99 udhcp_dump_packet(packet);
104 /* Construct a ip/udp header for a packet, send packet */
105 int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
106 uint32_t source_nip, int source_port,
107 uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
110 struct sockaddr_ll dest_sll;
111 struct ip_udp_dhcp_packet packet;
117 fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
123 memset(&dest_sll, 0, sizeof(dest_sll));
124 memset(&packet, 0, offsetof(struct ip_udp_dhcp_packet, data));
125 packet.data = *dhcp_pkt; /* struct copy */
127 dest_sll.sll_family = AF_PACKET;
128 dest_sll.sll_protocol = htons(ETH_P_IP);
129 dest_sll.sll_ifindex = ifindex;
130 dest_sll.sll_halen = 6;
131 memcpy(dest_sll.sll_addr, dest_arp, 6);
133 if (bind(fd, (struct sockaddr *)&dest_sll, sizeof(dest_sll)) < 0) {
138 /* We were sending full-sized DHCP packets (zero padded),
139 * but some badly configured servers were seen dropping them.
140 * Apparently they drop all DHCP packets >576 *ethernet* octets big,
141 * whereas they may only drop packets >576 *IP* octets big
142 * (which for typical Ethernet II means 590 octets: 6+6+2 + 576).
144 * In order to work with those buggy servers,
145 * we truncate packets after end option byte.
147 padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options);
149 packet.ip.protocol = IPPROTO_UDP;
150 packet.ip.saddr = source_nip;
151 packet.ip.daddr = dest_nip;
152 packet.udp.source = htons(source_port);
153 packet.udp.dest = htons(dest_port);
154 /* size, excluding IP header: */
155 packet.udp.len = htons(UDP_DHCP_SIZE - padding);
156 /* for UDP checksumming, ip.len is set to UDP packet len */
157 packet.ip.tot_len = packet.udp.len;
158 packet.udp.check = inet_cksum((uint16_t *)&packet,
159 IP_UDP_DHCP_SIZE - padding);
160 /* but for sending, it is set to IP packet len */
161 packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding);
162 packet.ip.ihl = sizeof(packet.ip) >> 2;
163 packet.ip.version = IPVERSION;
164 packet.ip.ttl = IPDEFTTL;
165 packet.ip.check = inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip));
167 udhcp_dump_packet(dhcp_pkt);
168 result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,
169 (struct sockaddr *) &dest_sll, sizeof(dest_sll));
175 bb_perror_msg(msg, "PACKET");
180 /* Let the kernel do all the work for packet generation */
181 int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
182 uint32_t source_nip, int source_port,
183 uint32_t dest_nip, int dest_port)
185 struct sockaddr_in sa;
191 fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
196 setsockopt_reuseaddr(fd);
198 memset(&sa, 0, sizeof(sa));
199 sa.sin_family = AF_INET;
200 sa.sin_port = htons(source_port);
201 sa.sin_addr.s_addr = source_nip;
202 if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
207 memset(&sa, 0, sizeof(sa));
208 sa.sin_family = AF_INET;
209 sa.sin_port = htons(dest_port);
210 sa.sin_addr.s_addr = dest_nip;
211 if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
216 udhcp_dump_packet(dhcp_pkt);
217 padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
218 result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
224 bb_perror_msg(msg, "UDP");