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authorRuss Dill <Russ.Dill@asu.edu>2002-10-14 21:41:28 +0000
committerRuss Dill <Russ.Dill@asu.edu>2002-10-14 21:41:28 +0000
commit61fb48930f45aa536584b2047f9e703186e8f69f (patch)
treee3b93e0a694be81939f8c4762553c43ffdb9b10b /networking/udhcp/packet.c
parent9060a7315980bb05f42eab76b88746d43e138188 (diff)
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added full udhcp integration
Diffstat (limited to 'networking/udhcp/packet.c')
-rw-r--r--networking/udhcp/packet.c203
1 files changed, 203 insertions, 0 deletions
diff --git a/networking/udhcp/packet.c b/networking/udhcp/packet.c
new file mode 100644
index 000000000..d9f715971
--- /dev/null
+++ b/networking/udhcp/packet.c
@@ -0,0 +1,203 @@
1#include <unistd.h>
2#include <string.h>
3#include <netinet/in.h>
4#include <sys/types.h>
5#include <sys/socket.h>
6#include <features.h>
7#if __GLIBC__ >=2 && __GLIBC_MINOR >= 1
8#include <netpacket/packet.h>
9#include <net/ethernet.h>
10#else
11#include <asm/types.h>
12#include <linux/if_packet.h>
13#include <linux/if_ether.h>
14#endif
15#include <errno.h>
16
17#include "packet.h"
18#include "debug.h"
19#include "dhcpd.h"
20#include "options.h"
21
22
23void init_header(struct dhcpMessage *packet, char type)
24{
25 memset(packet, 0, sizeof(struct dhcpMessage));
26 switch (type) {
27 case DHCPDISCOVER:
28 case DHCPREQUEST:
29 case DHCPRELEASE:
30 case DHCPINFORM:
31 packet->op = BOOTREQUEST;
32 break;
33 case DHCPOFFER:
34 case DHCPACK:
35 case DHCPNAK:
36 packet->op = BOOTREPLY;
37 }
38 packet->htype = ETH_10MB;
39 packet->hlen = ETH_10MB_LEN;
40 packet->cookie = htonl(DHCP_MAGIC);
41 packet->options[0] = DHCP_END;
42 add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
43}
44
45
46/* read a packet from socket fd, return -1 on read error, -2 on packet error */
47int get_packet(struct dhcpMessage *packet, int fd)
48{
49 int bytes;
50 int i;
51 const char broken_vendors[][8] = {
52 "MSFT 98",
53 ""
54 };
55 char unsigned *vendor;
56
57 memset(packet, 0, sizeof(struct dhcpMessage));
58 bytes = read(fd, packet, sizeof(struct dhcpMessage));
59 if (bytes < 0) {
60 DEBUG(LOG_INFO, "couldn't read on listening socket, ignoring");
61 return -1;
62 }
63
64 if (ntohl(packet->cookie) != DHCP_MAGIC) {
65 LOG(LOG_ERR, "received bogus message, ignoring");
66 return -2;
67 }
68 DEBUG(LOG_INFO, "Received a packet");
69
70 if (packet->op == BOOTREQUEST && (vendor = get_option(packet, DHCP_VENDOR))) {
71 for (i = 0; broken_vendors[i][0]; i++) {
72 if (vendor[OPT_LEN - 2] == (unsigned char) strlen(broken_vendors[i]) &&
73 !strncmp(vendor, broken_vendors[i], vendor[OPT_LEN - 2])) {
74 DEBUG(LOG_INFO, "broken client (%s), forcing broadcast",
75 broken_vendors[i]);
76 packet->flags |= htons(BROADCAST_FLAG);
77 }
78 }
79 }
80
81
82 return bytes;
83}
84
85
86u_int16_t checksum(void *addr, int count)
87{
88 /* Compute Internet Checksum for "count" bytes
89 * beginning at location "addr".
90 */
91 register int32_t sum = 0;
92 u_int16_t *source = (u_int16_t *) addr;
93
94 while (count > 1) {
95 /* This is the inner loop */
96 sum += *source++;
97 count -= 2;
98 }
99
100 /* Add left-over byte, if any */
101 if (count > 0) {
102 /* Make sure that the left-over byte is added correctly both
103 * with little and big endian hosts */
104 u_int16_t tmp = 0;
105 *(unsigned char *) (&tmp) = * (unsigned char *) source;
106 sum += tmp;
107 }
108 /* Fold 32-bit sum to 16 bits */
109 while (sum >> 16)
110 sum = (sum & 0xffff) + (sum >> 16);
111
112 return ~sum;
113}
114
115
116/* Constuct a ip/udp header for a packet, and specify the source and dest hardware address */
117int raw_packet(struct dhcpMessage *payload, u_int32_t source_ip, int source_port,
118 u_int32_t dest_ip, int dest_port, unsigned char *dest_arp, int ifindex)
119{
120 int fd;
121 int result;
122 struct sockaddr_ll dest;
123 struct udp_dhcp_packet packet;
124
125 if ((fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
126 DEBUG(LOG_ERR, "socket call failed: %s", strerror(errno));
127 return -1;
128 }
129
130 memset(&dest, 0, sizeof(dest));
131 memset(&packet, 0, sizeof(packet));
132
133 dest.sll_family = AF_PACKET;
134 dest.sll_protocol = htons(ETH_P_IP);
135 dest.sll_ifindex = ifindex;
136 dest.sll_halen = 6;
137 memcpy(dest.sll_addr, dest_arp, 6);
138 if (bind(fd, (struct sockaddr *)&dest, sizeof(struct sockaddr_ll)) < 0) {
139 DEBUG(LOG_ERR, "bind call failed: %s", strerror(errno));
140 close(fd);
141 return -1;
142 }
143
144 packet.ip.protocol = IPPROTO_UDP;
145 packet.ip.saddr = source_ip;
146 packet.ip.daddr = dest_ip;
147 packet.udp.source = htons(source_port);
148 packet.udp.dest = htons(dest_port);
149 packet.udp.len = htons(sizeof(packet.udp) + sizeof(struct dhcpMessage)); /* cheat on the psuedo-header */
150 packet.ip.tot_len = packet.udp.len;
151 memcpy(&(packet.data), payload, sizeof(struct dhcpMessage));
152 packet.udp.check = checksum(&packet, sizeof(struct udp_dhcp_packet));
153
154 packet.ip.tot_len = htons(sizeof(struct udp_dhcp_packet));
155 packet.ip.ihl = sizeof(packet.ip) >> 2;
156 packet.ip.version = IPVERSION;
157 packet.ip.ttl = IPDEFTTL;
158 packet.ip.check = checksum(&(packet.ip), sizeof(packet.ip));
159
160 result = sendto(fd, &packet, sizeof(struct udp_dhcp_packet), 0, (struct sockaddr *) &dest, sizeof(dest));
161 if (result <= 0) {
162 DEBUG(LOG_ERR, "write on socket failed: %s", strerror(errno));
163 }
164 close(fd);
165 return result;
166}
167
168
169/* Let the kernel do all the work for packet generation */
170int kernel_packet(struct dhcpMessage *payload, u_int32_t source_ip, int source_port,
171 u_int32_t dest_ip, int dest_port)
172{
173 int n = 1;
174 int fd, result;
175 struct sockaddr_in client;
176
177 if ((fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
178 return -1;
179
180 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &n, sizeof(n)) == -1)
181 return -1;
182
183 memset(&client, 0, sizeof(client));
184 client.sin_family = AF_INET;
185 client.sin_port = htons(source_port);
186 client.sin_addr.s_addr = source_ip;
187
188 if (bind(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
189 return -1;
190
191 memset(&client, 0, sizeof(client));
192 client.sin_family = AF_INET;
193 client.sin_port = htons(dest_port);
194 client.sin_addr.s_addr = dest_ip;
195
196 if (connect(fd, (struct sockaddr *)&client, sizeof(struct sockaddr)) == -1)
197 return -1;
198
199 result = write(fd, payload, sizeof(struct dhcpMessage));
200 close(fd);
201 return result;
202}
203
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