/* vi: set sw=4 ts=4: */
-
-#include <netinet/in.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
-
+/*
+ * Packet ops
+ *
+ * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
#include "common.h"
#include "dhcpd.h"
-#include "options.h"
-
+#include <netinet/in.h>
+#include <netinet/if_ether.h>
+#include <netpacket/packet.h>
-void FAST_FUNC udhcp_init_header(struct dhcpMessage *packet, char type)
+#if ENABLE_UDHCPC || ENABLE_UDHCPD
+void FAST_FUNC udhcp_init_header(struct dhcp_packet *packet, char type)
{
- memset(packet, 0, sizeof(struct dhcpMessage));
- packet->op = BOOTREQUEST;
+ memset(packet, 0, sizeof(*packet));
+ packet->op = BOOTREQUEST; /* if client to a server */
switch (type) {
case DHCPOFFER:
case DHCPACK:
case DHCPNAK:
- packet->op = BOOTREPLY;
+ packet->op = BOOTREPLY; /* if server to client */
}
- packet->htype = ETH_10MB;
- packet->hlen = ETH_10MB_LEN;
+ packet->htype = 1; /* ethernet */
+ packet->hlen = 6;
packet->cookie = htonl(DHCP_MAGIC);
- packet->options[0] = DHCP_END;
- add_simple_option(packet->options, DHCP_MESSAGE_TYPE, type);
+ if (DHCP_END != 0)
+ packet->options[0] = DHCP_END;
+ udhcp_add_simple_option(packet, DHCP_MESSAGE_TYPE, type);
}
+#endif
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
+void FAST_FUNC udhcp_dump_packet(struct dhcp_packet *packet)
+{
+ char buf[sizeof(packet->chaddr)*2 + 1];
+
+ if (dhcp_verbose < 2)
+ return;
+
+ bb_info_msg(
+ //" op %x"
+ //" htype %x"
+ " hlen %x"
+ //" hops %x"
+ " xid %x"
+ //" secs %x"
+ //" flags %x"
+ " ciaddr %x"
+ " yiaddr %x"
+ " siaddr %x"
+ " giaddr %x"
+ //" sname %s"
+ //" file %s"
+ //" cookie %x"
+ //" options %s"
+ //, packet->op
+ //, packet->htype
+ , packet->hlen
+ //, packet->hops
+ , packet->xid
+ //, packet->secs
+ //, packet->flags
+ , packet->ciaddr
+ , packet->yiaddr
+ , packet->siaddr_nip
+ , packet->gateway_nip
+ //, packet->sname[64]
+ //, packet->file[128]
+ //, packet->cookie
+ //, packet->options[]
+ );
+ *bin2hex(buf, (void *) packet->chaddr, sizeof(packet->chaddr)) = '\0';
+ bb_info_msg(" chaddr %s", buf);
+}
+#endif
-/* read a packet from socket fd, return -1 on read error, -2 on packet error */
-int FAST_FUNC udhcp_recv_kernel_packet(struct dhcpMessage *packet, int fd)
+/* Read a packet from socket fd, return -1 on read error, -2 on packet error */
+int FAST_FUNC udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd)
{
int bytes;
- unsigned char *vendor;
memset(packet, 0, sizeof(*packet));
bytes = safe_read(fd, packet, sizeof(*packet));
if (bytes < 0) {
- DEBUG("cannot read on listening socket, ignoring");
+ log1("packet read error, ignoring");
return bytes; /* returns -1 */
}
- if (packet->cookie != htonl(DHCP_MAGIC)) {
- bb_error_msg("received bogus message, ignoring");
+ if (bytes < offsetof(struct dhcp_packet, options)
+ || packet->cookie != htonl(DHCP_MAGIC)
+ ) {
+ bb_info_msg("packet with bad magic, ignoring");
return -2;
}
- DEBUG("Received a packet");
-
- if (packet->op == BOOTREQUEST) {
- vendor = get_option(packet, DHCP_VENDOR);
- if (vendor) {
-#if 0
- static const char broken_vendors[][8] = {
- "MSFT 98",
- ""
- };
- int i;
- for (i = 0; broken_vendors[i][0]; i++) {
- if (vendor[OPT_LEN - 2] == (uint8_t)strlen(broken_vendors[i])
- && !strncmp((char*)vendor, broken_vendors[i], vendor[OPT_LEN - 2])
- ) {
- DEBUG("broken client (%s), forcing broadcast",
- broken_vendors[i]);
- packet->flags |= htons(BROADCAST_FLAG);
- }
- }
-#else
- if (vendor[OPT_LEN - 2] == (uint8_t)(sizeof("MSFT 98")-1)
- && memcmp(vendor, "MSFT 98", sizeof("MSFT 98")-1) == 0
- ) {
- DEBUG("broken client (%s), forcing broadcast", "MSFT 98");
- packet->flags |= htons(BROADCAST_FLAG);
- }
-#endif
- }
- }
+ log1("received %s", "a packet");
+ udhcp_dump_packet(packet);
return bytes;
}
-
-uint16_t FAST_FUNC udhcp_checksum(void *addr, int count)
-{
- /* Compute Internet Checksum for "count" bytes
- * beginning at location "addr".
- */
- int32_t sum = 0;
- uint16_t *source = (uint16_t *) addr;
-
- while (count > 1) {
- /* This is the inner loop */
- sum += *source++;
- count -= 2;
- }
-
- /* Add left-over byte, if any */
- if (count > 0) {
- /* Make sure that the left-over byte is added correctly both
- * with little and big endian hosts */
- uint16_t tmp = 0;
- *(uint8_t*)&tmp = *(uint8_t*)source;
- sum += tmp;
- }
- /* Fold 32-bit sum to 16 bits */
- while (sum >> 16)
- sum = (sum & 0xffff) + (sum >> 16);
-
- return ~sum;
-}
-
-
/* Construct a ip/udp header for a packet, send packet */
-int FAST_FUNC udhcp_send_raw_packet(struct dhcpMessage *payload,
- uint32_t source_ip, int source_port,
- uint32_t dest_ip, int dest_port, const uint8_t *dest_arp, int ifindex)
+int FAST_FUNC udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
+ uint32_t source_nip, int source_port,
+ uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
+ int ifindex)
{
- struct sockaddr_ll dest;
- struct udp_dhcp_packet packet;
+ struct sockaddr_ll dest_sll;
+ struct ip_udp_dhcp_packet packet;
+ unsigned padding;
int fd;
int result = -1;
const char *msg;
- enum {
- IP_UPD_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
- UPD_DHCP_SIZE = IP_UPD_DHCP_SIZE - offsetof(struct udp_dhcp_packet, udp),
- };
-
fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
if (fd < 0) {
msg = "socket(%s)";
goto ret_msg;
}
- memset(&dest, 0, sizeof(dest));
- memset(&packet, 0, sizeof(packet));
- packet.data = *payload; /* struct copy */
+ memset(&dest_sll, 0, sizeof(dest_sll));
+ memset(&packet, 0, offsetof(struct ip_udp_dhcp_packet, data));
+ packet.data = *dhcp_pkt; /* struct copy */
- dest.sll_family = AF_PACKET;
- dest.sll_protocol = htons(ETH_P_IP);
- dest.sll_ifindex = ifindex;
- dest.sll_halen = 6;
- memcpy(dest.sll_addr, dest_arp, 6);
- if (bind(fd, (struct sockaddr *)&dest, sizeof(dest)) < 0) {
+ dest_sll.sll_family = AF_PACKET;
+ dest_sll.sll_protocol = htons(ETH_P_IP);
+ dest_sll.sll_ifindex = ifindex;
+ /*dest_sll.sll_hatype = ARPHRD_???;*/
+ /*dest_sll.sll_pkttype = PACKET_???;*/
+ dest_sll.sll_halen = 6;
+ memcpy(dest_sll.sll_addr, dest_arp, 6);
+
+ if (bind(fd, (struct sockaddr *)&dest_sll, sizeof(dest_sll)) < 0) {
msg = "bind(%s)";
goto ret_close;
}
+ /* We were sending full-sized DHCP packets (zero padded),
+ * but some badly configured servers were seen dropping them.
+ * Apparently they drop all DHCP packets >576 *ethernet* octets big,
+ * whereas they may only drop packets >576 *IP* octets big
+ * (which for typical Ethernet II means 590 octets: 6+6+2 + 576).
+ *
+ * In order to work with those buggy servers,
+ * we truncate packets after end option byte.
+ *
+ * However, RFC 1542 says "The IP Total Length and UDP Length
+ * must be large enough to contain the minimal BOOTP header of 300 octets".
+ * Thus, we retain enough padding to not go below 300 BOOTP bytes.
+ * Some devices have filters which drop DHCP packets shorter than that.
+ */
+ padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options);
+ if (padding > DHCP_SIZE - 300)
+ padding = DHCP_SIZE - 300;
+
packet.ip.protocol = IPPROTO_UDP;
- packet.ip.saddr = source_ip;
- packet.ip.daddr = dest_ip;
+ packet.ip.saddr = source_nip;
+ packet.ip.daddr = dest_nip;
packet.udp.source = htons(source_port);
packet.udp.dest = htons(dest_port);
/* size, excluding IP header: */
- packet.udp.len = htons(UPD_DHCP_SIZE);
+ packet.udp.len = htons(UDP_DHCP_SIZE - padding);
/* for UDP checksumming, ip.len is set to UDP packet len */
packet.ip.tot_len = packet.udp.len;
- packet.udp.check = udhcp_checksum(&packet, IP_UPD_DHCP_SIZE);
+ packet.udp.check = inet_cksum((uint16_t *)&packet,
+ IP_UDP_DHCP_SIZE - padding);
/* but for sending, it is set to IP packet len */
- packet.ip.tot_len = htons(IP_UPD_DHCP_SIZE);
+ packet.ip.tot_len = htons(IP_UDP_DHCP_SIZE - padding);
packet.ip.ihl = sizeof(packet.ip) >> 2;
packet.ip.version = IPVERSION;
packet.ip.ttl = IPDEFTTL;
- packet.ip.check = udhcp_checksum(&packet.ip, sizeof(packet.ip));
+ packet.ip.check = inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip));
- /* Currently we send full-sized DHCP packets (zero padded).
- * If you need to change this: last byte of the packet is
- * packet.data.options[end_option(packet.data.options)]
- */
- result = sendto(fd, &packet, IP_UPD_DHCP_SIZE, 0,
- (struct sockaddr *) &dest, sizeof(dest));
+ udhcp_dump_packet(dhcp_pkt);
+ result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,
+ (struct sockaddr *) &dest_sll, sizeof(dest_sll));
msg = "sendto";
ret_close:
close(fd);
return result;
}
-
/* Let the kernel do all the work for packet generation */
-int FAST_FUNC udhcp_send_kernel_packet(struct dhcpMessage *payload,
- uint32_t source_ip, int source_port,
- uint32_t dest_ip, int dest_port)
+int FAST_FUNC udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
+ uint32_t source_nip, int source_port,
+ uint32_t dest_nip, int dest_port)
{
- struct sockaddr_in client;
+ struct sockaddr_in sa;
+ unsigned padding;
int fd;
int result = -1;
const char *msg;
- enum {
- DHCP_SIZE = sizeof(struct dhcpMessage) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
- };
-
fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (fd < 0) {
msg = "socket(%s)";
}
setsockopt_reuseaddr(fd);
- memset(&client, 0, sizeof(client));
- client.sin_family = AF_INET;
- client.sin_port = htons(source_port);
- client.sin_addr.s_addr = source_ip;
- if (bind(fd, (struct sockaddr *)&client, sizeof(client)) == -1) {
+ memset(&sa, 0, sizeof(sa));
+ sa.sin_family = AF_INET;
+ sa.sin_port = htons(source_port);
+ sa.sin_addr.s_addr = source_nip;
+ if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
msg = "bind(%s)";
goto ret_close;
}
- memset(&client, 0, sizeof(client));
- client.sin_family = AF_INET;
- client.sin_port = htons(dest_port);
- client.sin_addr.s_addr = dest_ip;
- if (connect(fd, (struct sockaddr *)&client, sizeof(client)) == -1) {
+ memset(&sa, 0, sizeof(sa));
+ sa.sin_family = AF_INET;
+ sa.sin_port = htons(dest_port);
+ sa.sin_addr.s_addr = dest_nip;
+ if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
msg = "connect";
goto ret_close;
}
- /* Currently we send full-sized DHCP packets (see above) */
- result = safe_write(fd, payload, DHCP_SIZE);
+ udhcp_dump_packet(dhcp_pkt);
+ padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
+ if (padding > DHCP_SIZE - 300)
+ padding = DHCP_SIZE - 300;
+ result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
msg = "write";
ret_close:
close(fd);
projects / oweals / busybox.git / blobdiff