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Diffstat (limited to 'i/pc104/initrd/conf/busybox/networking/udhcp/clientpacket.c')
-rw-r--r--i/pc104/initrd/conf/busybox/networking/udhcp/clientpacket.c224
1 files changed, 224 insertions, 0 deletions
diff --git a/i/pc104/initrd/conf/busybox/networking/udhcp/clientpacket.c b/i/pc104/initrd/conf/busybox/networking/udhcp/clientpacket.c
new file mode 100644
index 0000000..69d7f2d
--- /dev/null
+++ b/i/pc104/initrd/conf/busybox/networking/udhcp/clientpacket.c
@@ -0,0 +1,224 @@
+/* vi: set sw=4 ts=4: */
+/* clientpacket.c
+ *
+ * Packet generation and dispatching functions for the DHCP client.
+ *
+ * Russ Dill <Russ.Dill@asu.edu> July 2001
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include <features.h>
+#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION
+#include <netpacket/packet.h>
+#include <net/ethernet.h>
+#else
+#include <asm/types.h>
+#include <linux/if_packet.h>
+#include <linux/if_ether.h>
+#endif
+
+#include "common.h"
+#include "dhcpd.h"
+#include "dhcpc.h"
+#include "options.h"
+
+
+/* Create a random xid */
+unsigned long random_xid(void)
+{
+ static int initialized;
+ if (!initialized) {
+ unsigned long seed;
+
+ if (open_read_close("/dev/urandom", &seed, sizeof(seed)) < 0) {
+ bb_info_msg("Cannot load seed "
+ "from /dev/urandom: %s", strerror(errno));
+ seed = time(0);
+ }
+ srand(seed);
+ initialized++;
+ }
+ return rand();
+}
+
+
+/* initialize a packet with the proper defaults */
+static void init_packet(struct dhcpMessage *packet, char type)
+{
+ udhcp_init_header(packet, type);
+ memcpy(packet->chaddr, client_config.arp, 6);
+ if (client_config.clientid)
+ add_option_string(packet->options, client_config.clientid);
+ if (client_config.hostname) add_option_string(packet->options, client_config.hostname);
+ if (client_config.fqdn) add_option_string(packet->options, client_config.fqdn);
+ add_option_string(packet->options, client_config.vendorclass);
+}
+
+
+/* Add a parameter request list for stubborn DHCP servers. Pull the data
+ * from the struct in options.c. Don't do bounds checking here because it
+ * goes towards the head of the packet. */
+static void add_requests(struct dhcpMessage *packet)
+{
+ int end = end_option(packet->options);
+ int i, len = 0;
+
+ packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
+ for (i = 0; dhcp_options[i].code; i++)
+ if (dhcp_options[i].flags & OPTION_REQ)
+ packet->options[end + OPT_DATA + len++] = dhcp_options[i].code;
+ packet->options[end + OPT_LEN] = len;
+ packet->options[end + OPT_DATA + len] = DHCP_END;
+
+}
+
+
+/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
+int send_discover(unsigned long xid, unsigned long requested)
+{
+ struct dhcpMessage packet;
+
+ init_packet(&packet, DHCPDISCOVER);
+ packet.xid = xid;
+ if (requested)
+ add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
+
+ add_requests(&packet);
+ bb_info_msg("Sending discover...");
+ return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
+ SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
+}
+
+
+/* Broadcasts a DHCP request message */
+int send_selecting(unsigned long xid, unsigned long server, unsigned long requested)
+{
+ struct dhcpMessage packet;
+ struct in_addr addr;
+
+ init_packet(&packet, DHCPREQUEST);
+ packet.xid = xid;
+
+ add_simple_option(packet.options, DHCP_REQUESTED_IP, requested);
+ add_simple_option(packet.options, DHCP_SERVER_ID, server);
+
+ add_requests(&packet);
+ addr.s_addr = requested;
+ bb_info_msg("Sending select for %s...", inet_ntoa(addr));
+ return udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
+ SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
+}
+
+
+/* Unicasts or broadcasts a DHCP renew message */
+int send_renew(unsigned long xid, unsigned long server, unsigned long ciaddr)
+{
+ struct dhcpMessage packet;
+ int ret = 0;
+
+ init_packet(&packet, DHCPREQUEST);
+ packet.xid = xid;
+ packet.ciaddr = ciaddr;
+
+ add_requests(&packet);
+ bb_info_msg("Sending renew...");
+ if (server)
+ ret = udhcp_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
+ else ret = udhcp_raw_packet(&packet, INADDR_ANY, CLIENT_PORT, INADDR_BROADCAST,
+ SERVER_PORT, MAC_BCAST_ADDR, client_config.ifindex);
+ return ret;
+}
+
+
+/* Unicasts a DHCP release message */
+int send_release(unsigned long server, unsigned long ciaddr)
+{
+ struct dhcpMessage packet;
+
+ init_packet(&packet, DHCPRELEASE);
+ packet.xid = random_xid();
+ packet.ciaddr = ciaddr;
+
+ add_simple_option(packet.options, DHCP_REQUESTED_IP, ciaddr);
+ add_simple_option(packet.options, DHCP_SERVER_ID, server);
+
+ bb_info_msg("Sending release...");
+ return udhcp_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
+}
+
+
+/* return -1 on errors that are fatal for the socket, -2 for those that aren't */
+int get_raw_packet(struct dhcpMessage *payload, int fd)
+{
+ int bytes;
+ struct udp_dhcp_packet packet;
+ uint32_t source, dest;
+ uint16_t check;
+
+ memset(&packet, 0, sizeof(struct udp_dhcp_packet));
+ bytes = read(fd, &packet, sizeof(struct udp_dhcp_packet));
+ if (bytes < 0) {
+ DEBUG("Cannot read on raw listening socket - ignoring");
+ usleep(500000); /* possible down interface, looping condition */
+ return -1;
+ }
+
+ if (bytes < (int) (sizeof(struct iphdr) + sizeof(struct udphdr))) {
+ DEBUG("Message too short, ignoring");
+ return -2;
+ }
+
+ if (bytes < ntohs(packet.ip.tot_len)) {
+ DEBUG("Truncated packet");
+ return -2;
+ }
+
+ /* ignore any extra garbage bytes */
+ bytes = ntohs(packet.ip.tot_len);
+
+ /* Make sure its the right packet for us, and that it passes sanity checks */
+ if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION
+ || packet.ip.ihl != sizeof(packet.ip) >> 2
+ || packet.udp.dest != htons(CLIENT_PORT)
+ || bytes > (int) sizeof(struct udp_dhcp_packet)
+ || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
+ ) {
+ DEBUG("Unrelated/bogus packet");
+ return -2;
+ }
+
+ /* check IP checksum */
+ check = packet.ip.check;
+ packet.ip.check = 0;
+ if (check != udhcp_checksum(&(packet.ip), sizeof(packet.ip))) {
+ DEBUG("bad IP header checksum, ignoring");
+ return -1;
+ }
+
+ /* verify the UDP checksum by replacing the header with a psuedo header */
+ source = packet.ip.saddr;
+ dest = packet.ip.daddr;
+ check = packet.udp.check;
+ packet.udp.check = 0;
+ memset(&packet.ip, 0, sizeof(packet.ip));
+
+ packet.ip.protocol = IPPROTO_UDP;
+ packet.ip.saddr = source;
+ packet.ip.daddr = dest;
+ packet.ip.tot_len = packet.udp.len; /* cheat on the psuedo-header */
+ if (check && check != udhcp_checksum(&packet, bytes)) {
+ bb_error_msg("packet with bad UDP checksum received, ignoring");
+ return -2;
+ }
+
+ memcpy(payload, &(packet.data), bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
+
+ if (ntohl(payload->cookie) != DHCP_MAGIC) {
+ bb_error_msg("received bogus message (bad magic) - ignoring");
+ return -2;
+ }
+ DEBUG("oooooh!!! got some!");
+ return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
+
+}