Enable seamless netboot on IPv6 network

To boot from an IPv6 network user has to type "boot net:ipv6" from SLOF prompt. This
is inconvenient in auto-install environment. This patch addresses this issue by falling
back to IPv6 booting in case IPv4 booting fails (No DHCPv4 response).

Signed-off-by: Avik Sil <aviksil@linux.vnet.ibm.com>

7 files changed, 81 insertions, 39 deletions

diff --git a/clients/net-snk/app/netapps/netapps.h b/clients/net-snk/app/netapps/netapps.h
index 8b0a5e7..18e607f 100644
--- a/clients/net-snk/app/netapps/netapps.h
+++ b/clients/net-snk/app/netapps/netapps.h
@@ -10,6 +10,14 @@
  *     IBM Corporation - initial implementation
  *****************************************************************************/
 
+#ifndef _NETAPPS_H_
+#define _NETAPPS_H_
+
+#include <netlib/tftp.h>
+
+#define F_IPV4	4
+#define F_IPV6	6
+
 int netboot(int argc, char *argv[]);
 int netsave(int argc, char *argv[]);
 int netflash(int argc, char *argv[]);
@@ -17,3 +25,6 @@ int bcmflash(int argc, char *argv[]);
 int mac_sync(int argc, char *argv[]);
 int net_eeprom_version( void );
 int ping(int argc, char *argv[]);
+int dhcp(char *ret_buffer, filename_ip_t * fn_ip, unsigned int retries, int flags);
+
+#endif
diff --git a/clients/net-snk/app/netapps/netboot.c b/clients/net-snk/app/netapps/netboot.c
index 6b7bc36..863e073 100644
--- a/clients/net-snk/app/netapps/netboot.c
+++ b/clients/net-snk/app/netapps/netboot.c
@@ -34,7 +34,7 @@
 #define IP_INIT_DHCPV6_STATELESS    3
 #define IP_INIT_IPV6_MANUAL         4
 
-#define DEFAULT_BOOT_RETRIES 600
+#define DEFAULT_BOOT_RETRIES 10
 #define DEFAULT_TFTP_RETRIES 20
 static int ip_version = 4;
 
@@ -308,6 +308,63 @@ parse_args(const char *arg_str, obp_tftp_args_t *obp_tftp_args)
 	}
 }
 
+/**
+ * DHCP: Wrapper for obtaining IP and configuration info from DHCP server
+ *       for both IPv4 and IPv6.
+ *       (makes several attempts).
+ *
+ * @param  ret_buffer    buffer for returning BOOTP-REPLY packet data
+ * @param  fn_ip         contains the following configuration information:
+ *                       client MAC, client IP, TFTP-server MAC,
+ *                       TFTP-server IP, Boot file name
+ * @param  retries       No. of DHCP attempts
+ * @param  flags         flags for specifying type of dhcp attempt (IPv4/IPv6)
+ *                       ZERO   - attempt DHCPv4 followed by DHCPv6
+ *                       F_IPV4 - attempt only DHCPv4
+ *                       F_IPV6 - attempt only DHCPv6
+ * @return               ZERO - IP and configuration info obtained;
+ *                       NON ZERO - error condition occurs.
+ */
+int dhcp(char *ret_buffer, filename_ip_t * fn_ip, unsigned int retries, int flags)
+{
+	int i = (int) retries+1;
+	int rc = -1;
+
+	printf("    ");
+
+	do {
+		printf("\b\b\b%03d", i-1);
+		if (getchar() == 27) {
+			printf("\nAborted\n");
+			return -1;
+		}
+		if (!--i) {
+			printf("\nGiving up after %d DHCP requests\n", retries);
+			return -1;
+		}
+		if (!flags || (flags == F_IPV4)) {
+			ip_version = 4;
+			rc = dhcpv4(ret_buffer, fn_ip);
+		}
+		if ((!flags && (rc == -1)) || (flags == F_IPV6)) {
+			ip_version = 6;
+			set_ipv6_address(0);
+			rc = dhcpv6(ret_buffer, fn_ip);
+			if (rc == 0) {
+				printf("\n");
+				memcpy(&fn_ip->own_ip6, get_ipv6_address(), 16);
+				break;
+			}
+
+		}
+		if (rc != -1) /* either success or non-dhcp failure */
+			break;
+	} while (1);
+	printf("\b\b\b\b");
+
+	return rc;
+}
+
 int
 netboot(int argc, char *argv[])
 {
@@ -439,12 +496,12 @@ netboot(int argc, char *argv[])
 		break;
 	case IP_INIT_DHCP:
 		printf("  Requesting IP address via DHCP: ");
-		rc = dhcp(ret_buffer, &fn_ip, obp_tftp_args.bootp_retries);
+		rc = dhcp(ret_buffer, &fn_ip, obp_tftp_args.bootp_retries, 0);
 		break;
 	case IP_INIT_DHCPV6_STATELESS:
-		set_ipv6_address(0);
-		rc = do_dhcpv6 (ret_buffer, &fn_ip, 10, DHCPV6_STATELESS);
-		memcpy(&fn_ip.own_ip6, get_ipv6_address(), 16);
+		printf("  Requesting information via DHCPv6: ");
+		rc = dhcp(ret_buffer, &fn_ip,
+			  obp_tftp_args.bootp_retries, F_IPV6);
 		break;
 	case IP_INIT_IPV6_MANUAL:
 		set_ipv6_address(&obp_tftp_args.ci6addr);
diff --git a/clients/net-snk/app/netapps/ping.c b/clients/net-snk/app/netapps/ping.c
index b810484..8376f48 100644
--- a/clients/net-snk/app/netapps/ping.c
+++ b/clients/net-snk/app/netapps/ping.c
@@ -152,7 +152,7 @@ ping(int argc, char *argv[])
 	if (!ping_args.client_ip.integer) {
 		/* Get ip address for our mac address */
 		printf("  Requesting IP address via DHCP: ");
-		arp_failed = dhcp(0, &fn_ip, 30);
+		arp_failed = dhcp(0, &fn_ip, 30, F_IPV4);
 
 		if (arp_failed == -1) {
 			printf("\n  DHCP: Could not get ip address\n");
diff --git a/clients/net-snk/app/netlib/dhcp.c b/clients/net-snk/app/netlib/dhcp.c
index 0fa0615..22bf1f6 100644
--- a/clients/net-snk/app/netlib/dhcp.c
+++ b/clients/net-snk/app/netlib/dhcp.c
@@ -173,20 +173,8 @@ static char   * response_buffer;
 
 /*>>>>>>>>>>>>>>>>>>>>>>>>>>>> IMPLEMENTATION <<<<<<<<<<<<<<<<<<<<<<<<<<<*/
 
-/**
- * DHCP: Obtains IP and configuration info from DHCP server
- *       (makes several attempts).
- *
- * @param  boot_device   a socket number used to send and receive packets
- * @param  fn_ip         contains the following configuration information:
- *                       client MAC, client IP, TFTP-server MAC, 
- *                       TFTP-server IP, Boot file name
- * @return               ZERO - IP and configuration info obtained;
- *                       NON ZERO - error condition occurs.
- */
 int32_t
-dhcp(char *ret_buffer, filename_ip_t * fn_ip, unsigned int retries) {
-	int i = (int) retries+1;
+dhcpv4(char *ret_buffer, filename_ip_t * fn_ip) {
 
 	uint32_t dhcp_tftp_ip     = 0;
 	strcpy((char *) dhcp_filename, "");
@@ -194,20 +182,8 @@ dhcp(char *ret_buffer, filename_ip_t * fn_ip, unsigned int retries) {
 
 	response_buffer = ret_buffer;
 
-	printf("    ");
-
-	do {
-		printf("\b\b\b%03d", i-1);
-		if (getchar() == 27) {
-			printf("\nAborted\n");
-			return -1;
-		}
-		if (!--i) {
-			printf("\nGiving up after %d DHCP requests\n", retries);
-			return -1;
-		}
-	} while (!dhcp_attempt());
-	printf("\b\b\b\b");
+	if (dhcp_attempt() == 0)
+		return -1;
 
 	if (fn_ip->own_ip) {
 		dhcp_own_ip = fn_ip->own_ip;
diff --git a/clients/net-snk/app/netlib/dhcp.h b/clients/net-snk/app/netlib/dhcp.h
index 73e0d01..3aab4ef 100644
--- a/clients/net-snk/app/netlib/dhcp.h
+++ b/clients/net-snk/app/netlib/dhcp.h
@@ -44,7 +44,7 @@ struct btphdr {
 };
 
 int bootp(char *ret_buffer, filename_ip_t *, unsigned int);
-int dhcp(char *ret_buffer, filename_ip_t *, unsigned int);
+int dhcpv4(char *ret_buffer, filename_ip_t *);
 void dhcp_send_release(void);
 
 /* Handles DHCP-packets, which are detected by receive_ether. */
diff --git a/clients/net-snk/app/netlib/dhcpv6.c b/clients/net-snk/app/netlib/dhcpv6.c
index 9749700..53cc7d3 100644
--- a/clients/net-snk/app/netlib/dhcpv6.c
+++ b/clients/net-snk/app/netlib/dhcpv6.c
@@ -95,7 +95,7 @@ dhcpv6_attempt(void)
 	dhcpv6_state = DHCPV6_STATE_SELECT;
 
 	// setting up a timer with a timeout of two seconds
-	for (sec = 0; sec < 4; sec++) {
+	for (sec = 0; sec < 2; sec++) {
 		set_timer(TICKS_SEC);
 		do {
 			receive_ether();
@@ -115,8 +115,7 @@ dhcpv6_attempt(void)
 }
 
 int32_t
-do_dhcpv6 ( char *ret_buffer, void *fn_ip,
-	    unsigned int retries, uint8_t mode)
+dhcpv6 ( char *ret_buffer, void *fn_ip)
 {
 	my_fn_ip = (filename_ip_t *) fn_ip;
 	if( !dhcpv6_attempt()) {
diff --git a/clients/net-snk/app/netlib/dhcpv6.h b/clients/net-snk/app/netlib/dhcpv6.h
index 0b7b9c7..078a9f1 100644
--- a/clients/net-snk/app/netlib/dhcpv6.h
+++ b/clients/net-snk/app/netlib/dhcpv6.h
@@ -77,8 +77,7 @@
 #define DUID_LL		3 /* DUID based on Link-layer Address */
 
 /* Prototypes */
-int32_t do_dhcpv6 ( char *ret_buffer, void *fn_ip,
-		    unsigned int retries, uint8_t mode);
+int32_t dhcpv6 ( char *ret_buffer, void *fn_ip);
 uint32_t handle_dhcpv6(uint8_t * , int32_t);
 
 struct dhcp6_gen_option {