}
}
+/* RFC 2131
+ * 4.4.4 Use of broadcast and unicast
+ *
+ * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
+ * messages, unless the client knows the address of a DHCP server.
+ * The client unicasts DHCPRELEASE messages to the server. Because
+ * the client is declining the use of the IP address supplied by the server,
+ * the client broadcasts DHCPDECLINE messages.
+ *
+ * When the DHCP client knows the address of a DHCP server, in either
+ * INIT or REBOOTING state, the client may use that address
+ * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
+ * The client may also use unicast to send DHCPINFORM messages
+ * to a known DHCP server. If the client receives no response to DHCP
+ * messages sent to the IP address of a known DHCP server, the DHCP
+ * client reverts to using the IP broadcast address.
+ */
static int raw_bcast_from_client_config_ifindex(struct dhcpMessage *packet)
{
#if ENABLE_FEATURE_UDHCPC_ARPING
/* Broadcast a DHCP decline message */
-//FIXME: maybe it should be unicast?
int FAST_FUNC send_decline(uint32_t xid, uint32_t server, uint32_t requested)
{
struct dhcpMessage packet;
/* Broadcasts a DHCP request message */
-//FIXME: maybe it should be unicast?
+/* RFC 2131 3.1 paragraph 3:
+ * "The client _broadcasts_ a DHCPREQUEST message..."
+ */
int FAST_FUNC send_select(uint32_t xid, uint32_t server, uint32_t requested)
{
struct dhcpMessage packet;
#define DHCP_OPTIONS_BUFSIZE 308
struct dhcpMessage {
- uint8_t op;
- uint8_t htype;
- uint8_t hlen;
- uint8_t hops;
- uint32_t xid;
- uint16_t secs;
- uint16_t flags;
- uint32_t ciaddr;
- uint32_t yiaddr;
- uint32_t siaddr;
- uint32_t giaddr;
- uint8_t chaddr[16];
- uint8_t sname[64];
- uint8_t file[128];
- uint32_t cookie;
+ uint8_t op; /* 1 = BOOTREQUEST, 2 = BOOTREPLY */
+ uint8_t htype; /* hardware address type. 1 = 10mb ethernet */
+ uint8_t hlen; /* hardware address length */
+ uint8_t hops; /* used by relay agents only */
+ uint32_t xid; /* unique id */
+ uint16_t secs; /* elapsed since client began acquisition/renewal */
+ uint16_t flags; /* only one flag so far: */
+#define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
+ uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
+ uint32_t yiaddr; /* 'your' (client) IP address */
+ uint32_t siaddr; /* IP address of next server to use in bootstrap,
+ * returned in DHCPOFFER, DHCPACK by server */
+ uint32_t giaddr; /* relay agent IP address */
+ uint8_t chaddr[16];/* link-layer client hardware address (MAC) */
+ uint8_t sname[64]; /* server host name (ASCIZ) */
+ uint8_t file[128]; /* boot file name (ASCIZ) */
+ uint32_t cookie; /* fixed first four option bytes (99,130,83,99 dec) */
uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
} PACKED;
}
/* select() didn't timeout, something did happen. */
- /* Is is a packet? */
+ /* Is it a packet? */
if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
int len;
/* A packet is ready, read it */
continue;
if (packet.xid != xid) {
- DEBUG("Ignoring XID %x (our xid is %x)",
+ DEBUG("Ignoring xid %x (our xid is %x)",
(unsigned)packet.xid, (unsigned)xid);
continue;
}
bb_error_msg("no lease time with ACK, using 1 hour lease");
lease_seconds = 60 * 60;
} else {
- /* can be misaligned, thus memcpy */
- memcpy(&lease_seconds, temp, 4);
+ /* it IS unaligned sometimes, don't "optimize" */
+ lease_seconds = get_unaligned_u32p((uint32_t*)temp);
lease_seconds = ntohl(lease_seconds);
lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
if (lease_seconds < 10) /* and not too small */
lease_seconds = 10;
}
-//FIXME: why do we check ARP only after we've got DHCPACK?
-//Shouldn't we do it immediately after DHCPOFFER?
#if ENABLE_FEATURE_UDHCPC_ARPING
if (opt & OPT_a) {
+/* RFC 2131 3.1 paragraph 5:
+ * "The client receives the DHCPACK message with configuration
+ * parameters. The client SHOULD perform a final check on the
+ * parameters (e.g., ARP for allocated network address), and notes
+ * the duration of the lease specified in the DHCPACK message. At this
+ * point, the client is configured. If the client detects that the
+ * address is already in use (e.g., through the use of ARP),
+ * the client MUST send a DHCPDECLINE message to the server and restarts
+ * the configuration process..." */
if (!arpping(packet.yiaddr,
(uint32_t) 0,
client_config.arp,
) {
bb_info_msg("offered address is in use "
"(got ARP reply), declining");
-//NB: not clear whether it should be unicast or bcast.
-//Currently it is a bcast. Why?
send_decline(xid, server_addr, packet.yiaddr);
if (state != REQUESTING)
}
requested_ip = packet.yiaddr;
udhcp_run_script(&packet,
- ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
+ ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
state = BOUND;
change_listen_mode(LISTEN_NONE);
#define ETH_10MB 1
#define ETH_10MB_LEN 6
-#define DHCPDISCOVER 1
-#define DHCPOFFER 2
-#define DHCPREQUEST 3
-#define DHCPDECLINE 4
-#define DHCPACK 5
-#define DHCPNAK 6
-#define DHCPRELEASE 7
-#define DHCPINFORM 8
-
-#define BROADCAST_FLAG 0x8000
+#define DHCPDISCOVER 1 /* client -> server */
+#define DHCPOFFER 2 /* client <- server */
+#define DHCPREQUEST 3 /* client -> server */
+#define DHCPDECLINE 4 /* client -> server */
+#define DHCPACK 5 /* client <- server */
+#define DHCPNAK 6 /* client <- server */
+#define DHCPRELEASE 7 /* client -> server */
+#define DHCPINFORM 8 /* client -> server */
#define OPTION_FIELD 0
#define FILE_FIELD 1
void FAST_FUNC udhcp_init_header(struct dhcpMessage *packet, char type)
{
memset(packet, 0, sizeof(struct dhcpMessage));
- packet->op = BOOTREQUEST;
+ 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;
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",
+ DEBUG("broken client (%s), forcing broadcast replies",
broken_vendors[i]);
packet->flags |= htons(BROADCAST_FLAG);
}
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");
+ DEBUG("broken client (%s), forcing broadcast replies", "MSFT 98");
packet->flags |= htons(BROADCAST_FLAG);
}
#endif
DEBUG("unicasting packet to client ciaddr");
ciaddr = payload->ciaddr;
chaddr = payload->chaddr;
- } else if (ntohs(payload->flags) & BROADCAST_FLAG) {
+ } else if (payload->flags & htons(BROADCAST_FLAG)) {
DEBUG("broadcasting packet to client (requested)");
ciaddr = INADDR_BROADCAST;
chaddr = MAC_BCAST_ADDR;
projects / platform / upstream / busybox.git / commitdiff