net: dhcp6: Add DHCPv6 (DHCP for IPv6)

Adds DHCPv6 protocol to u-boot.

Allows for address assignement with DHCPv6 4-message exchange
(SOLICIT->ADVERTISE->REQUEST->REPLY).  Includes DHCPv6 options
required by RFC 8415.  Also adds DHCPv6 options required
for PXE boot.

Possible enhancements:
- Duplicate address detection on DHCPv6 assigned address
- IPv6 address assignement through SLAAC
- Sending/parsing other DHCPv6 options (NTP, DNS, etc...)

Signed-off-by: Sean Edmond <seanedmond@microsoft.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

1 files changed, 256 insertions, 0 deletions

diff --git a/net/dhcpv6.h b/net/dhcpv6.h
new file mode 100644
index 0000000..80ca520
--- /dev/null
+++ b/net/dhcpv6.h
@@ -0,0 +1,256 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) Microsoft Corporation
+ * Author: Sean Edmond <seanedmond@microsoft.com>
+ *
+ */
+
+#ifndef __DHCP6_H__
+#define __DHCP6_H__
+
+/* Message types */
+#define DHCP6_MSG_SOLICIT	1
+#define DHCP6_MSG_ADVERTISE	2
+#define DHCP6_MSG_REQUEST	3
+#define DHCP6_MSG_REPLY		7
+
+/* Option Codes */
+#define DHCP6_OPTION_CLIENTID		1
+#define DHCP6_OPTION_SERVERID		2
+#define DHCP6_OPTION_IA_NA		3
+#define DHCP6_OPTION_IA_TA		4
+#define DHCP6_OPTION_IAADDR		5
+#define DHCP6_OPTION_ORO		6
+#define DHCP6_OPTION_PREFERENCE		7
+#define DHCP6_OPTION_ELAPSED_TIME	8
+#define DHCP6_OPTION_STATUS_CODE	13
+#define DHCP6_OPTION_OPT_BOOTFILE_URL	59
+#define DHCP6_OPTION_OPT_BOOTFILE_PARAM	60
+#define DHCP6_OPTION_SOL_MAX_RT		82
+#define DHCP6_OPTION_CLIENT_ARCH_TYPE	61
+#define DHCP6_OPTION_VENDOR_CLASS	16
+#define DHCP6_OPTION_NII		62
+
+/* DUID */
+#define DUID_TYPE_LL		3
+#define DUID_HW_TYPE_ENET	1
+#define DUID_LL_SIZE		(sizeof(struct dhcp6_option_duid_ll) + ETH_ALEN)
+#define DUID_MAX_SIZE		DUID_LL_SIZE /* only supports DUID-LL currently */
+
+/* vendor-class-data to send in vendor clas option */
+#define DHCP6_VCI_STRING	"U-boot"
+
+#define DHCP6_MULTICAST_ADDR	"ff02::1:2"	/* DHCP multicast address */
+
+/* DHCP6 States supported */
+enum dhcp6_state {
+	DHCP6_INIT,
+	DHCP6_SOLICIT,
+	DHCP6_REQUEST,
+	DHCP6_DONE,
+	DHCP6_FAIL,
+};
+
+/* DHCP6 Status codes */
+enum dhcp6_status {
+	DHCP6_SUCCESS = 0,
+	DHCP6_UNSPEC_FAIL = 1,
+	DHCP6_NO_ADDRS_AVAIL = 2,
+	DHCP6_NO_BINDING = 3,
+	DHCP6_NOT_ON_LINK = 4,
+	DHCP6_USE_MULTICAST = 5,
+	DHCP6_NO_PREFIX_AVAIL = 6,
+};
+
+/* DHCP6 message header format */
+struct dhcp6_hdr {
+	unsigned int msg_type : 8;	/* message type */
+	unsigned int trans_id : 24;	/* transaction ID */
+} __packed;
+
+/* DHCP6 option header format */
+struct dhcp6_option_hdr {
+	__be16	option_id;	/* option id */
+	__be16	option_len;	/* Option length */
+	u8	option_data[0];	/* Option data */
+} __packed;
+
+/* DHCP6_OPTION_CLIENTID option (DUID-LL) */
+struct dhcp6_option_duid_ll {
+	__be16	duid_type;
+	__be16	hw_type;
+	u8	ll_addr[0];
+} __packed;
+
+/* DHCP6_OPTION_ELAPSED_TIME option */
+struct dhcp6_option_elapsed_time {
+	__be16	elapsed_time;
+} __packed;
+
+/* DHCP6_OPTION_IA_TA option */
+struct dhcp6_option_ia_ta {
+	__be32	iaid;
+	u8	ia_ta_options[0];
+} __packed;
+
+/* DHCP6_OPTION_IA_NA option */
+struct dhcp6_option_ia_na {
+	__be32	iaid;
+	__be32	t1;
+	__be32	t2;
+	u8	ia_na_options[0];
+} __packed;
+
+/* OPTION_ORO option */
+struct dhcp6_option_oro  {
+	__be16	req_option_code[0];
+} __packed;
+
+/* DHCP6_OPTION_CLIENT_ARCH_TYPE option */
+struct dhcp6_option_client_arch {
+	__be16	arch_type[0];
+} __packed;
+
+/* vendor-class-data inside OPTION_VENDOR_CLASS option */
+struct vendor_class_data {
+	__be16	vendor_class_len;
+	u8	opaque_data[0];
+} __packed;
+
+/* DHCP6_OPTION_VENDOR_CLASS option */
+struct dhcp6_option_vendor_class {
+	__be32				enterprise_number;
+	struct vendor_class_data	vendor_class_data[0];
+} __packed;
+
+/**
+ * struct dhcp6_rx_pkt_status - Structure that holds status
+ *                              from a received message
+ * @client_id_match: Client ID was found and matches DUID sent
+ * @server_id_found: Server ID was found in the message
+ * @server_uid_ptr: Pointer to received server ID
+ * @server_uid_size: Size of received server ID
+ * @ia_addr_found: IA addr option was found in received message
+ * @ia_addr_ipv6: The IPv6 address received in IA
+ * @ia_status_code: Status code received in the IA
+ * @status_code: Top-level status code received
+ * @preference: Preference code received
+ */
+struct dhcp6_rx_pkt_status {
+	bool			client_id_match;
+	bool			server_id_found;
+	uchar			*server_uid_ptr;
+	u16			server_uid_size;
+	bool			ia_addr_found;
+	struct in6_addr		ia_addr_ipv6;
+	enum dhcp6_status	ia_status_code;
+	enum dhcp6_status	status_code;
+	u8			preference;
+};
+
+/**
+ * struct dhcp6_server_uid - Structure that holds the server UID
+ *                             received from an ADVERTISE and saved
+ *                             given the server selection criteria.
+ * @uid_ptr: Dynamically allocated and copied server UID
+ * @uid_size: Size of the server UID in uid_ptr (in bytes)
+ * @preference: Preference code associated with this server UID
+ */
+struct dhcp6_server_uid {
+	uchar	*uid_ptr;
+	u16	uid_size;
+	u8	preference;
+};
+
+/**
+ * struct dhcp6_sm_params - Structure that holds DHCP6
+ *                          state machine parameters
+ * @curr_state: current DHCP6 state
+ * @next_state: next DHCP6 state
+ * @dhcp6_start_ms: timestamp DHCP6 start
+ * @dhcp6_retry_start_ms: timestamp of current TX message start
+ * @dhcp6_retry_ms: timestamp of last retransmission
+ * @retry_cnt: retry count
+ * @trans_id: transaction ID
+ * @ia_id: transmitted IA ID
+ * @irt_ms: Initial retransmission time (in ms)
+ * @mrt_ms: Maximum retransmission time (in ms)
+ * @mrc: Maximum retransmission count
+ * @mrd_ms: Maximum retransmission duration (in ms)
+ * @rt_ms: retransmission timeout (is ms)
+ * @rt_prev_ms: previous retransmission timeout
+ * @rx_status: Status from received message
+ * @server_uid: Saved Server UID for selected server
+ * @duid: pointer to transmitted Client DUID
+ */
+struct dhcp6_sm_params {
+	enum dhcp6_state		curr_state;
+	enum dhcp6_state		next_state;
+	ulong				dhcp6_start_ms;
+	ulong				dhcp6_retry_start_ms;
+	ulong				dhcp6_retry_ms;
+	u32				retry_cnt;
+	u32				trans_id;
+	u32				ia_id;
+	int				irt_ms;
+	int				mrt_ms;
+	int				mrc;
+	int				mrd_ms;
+	int				rt_ms;
+	int				rt_prev_ms;
+	struct dhcp6_rx_pkt_status	rx_status;
+	struct dhcp6_server_uid		server_uid;
+	char				duid[DUID_MAX_SIZE];
+};
+
+/* Starts a DHCPv6 4-message exchange as a DHCPv6 client. On successful exchange,
+ * the DHCPv6 state machine will transition from internal states:
+ *	DHCP6_INIT->DHCP6_SOLICIT->DHCP6_REQUEST->DHCP6_DONE
+ *
+ * Transmitted SOLICIT and REQUEST packets will set/request the minimum required
+ * DHCPv6 options to PXE boot.
+ *
+ * After a successful exchange, the DHCPv6 assigned address will be set in net_ip6
+ *
+ * Additionally, the following will be set after receiving these options:
+ * DHCP6_OPTION_OPT_BOOTFILE_URL (option 59) -> net_server_ip6, net_boot_file_name
+ * DHCP6_OPTION_OPT_BOOTFILE_PARAM (option 60) - > pxelinux_configfile
+ *
+ * Illustration of a 4-message exchange with 2 servers (copied from
+ * https://www.rfc-editor.org/rfc/rfc8415):
+ *
+ *               Server                          Server
+ *           (not selected)      Client        (selected)
+ *
+ *                 v               v               v
+ *                 |               |               |
+ *                 |     Begins initialization     |
+ *                 |               |               |
+ *    start of     | _____________/|\_____________ |
+ *    4-message    |/ Solicit      | Solicit      \|
+ *    exchange     |               |               |
+ *             Determines          |          Determines
+ *            configuration        |         configuration
+ *                 |               |               |
+ *                 |\              |  ____________/|
+ *                 | \________     | /Advertise    |
+ *                 | Advertise\    |/              |
+ *                 |           \   |               |
+ *                 |      Collects Advertises      |
+ *                 |             \ |               |
+ *                 |     Selects configuration     |
+ *                 |               |               |
+ *                 | _____________/|\_____________ |
+ *                 |/ Request      |  Request     \|
+ *                 |               |               |
+ *                 |               |     Commits configuration
+ *                 |               |               |
+ *    end of       |               | _____________/|
+ *    4-message    |               |/ Reply        |
+ *    exchange     |               |               |
+ *                 |    Initialization complete    |
+ *                 |               |               |
+ */
+void dhcp6_start(void);
+
+#endif /* __DHCP6_H__ */