Re: [PATCH v3 1/3] net: dhcp6: Add DHCPv6 (DHCP for IPv6)

Ramon Fried
2023-04-25T19:11:33Z

On Tue, Apr 11, 2023 at 8:48 PM <seanedmond@linux.microsoft.com> wrote:
>
> From: Sean Edmond <seanedmond@microsoft.com>
>
> 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>
> ---
> include/net.h | 6 +-
> net/Makefile | 1 +
> net/dhcpv6.c | 719 ++++++++++++++++++++++++++++++++++++++++++++++++++
> net/dhcpv6.h | 256 ++++++++++++++++++
> net/net.c | 11 +-
> 5 files changed, 989 insertions(+), 4 deletions(-)
> create mode 100644 net/dhcpv6.c
> create mode 100644 net/dhcpv6.h
>
> diff --git a/include/net.h b/include/net.h
> index 399af5e064..181a6e3b13 100644
> --- a/include/net.h
> +++ b/include/net.h
> @@ -484,6 +484,8 @@ extern char net_hostname[32]; /* Our hostname */
> #ifdef CONFIG_NET
> extern char net_root_path[CONFIG_BOOTP_MAX_ROOT_PATH_LEN]; /* Our root path */
> #endif
> +/* Indicates whether the pxe path prefix / config file was specified in dhcp option */
> +extern char *pxelinux_configfile;
> /** END OF BOOTP EXTENTIONS **/
> extern u8 net_ethaddr[ARP_HLEN]; /* Our ethernet address */
> extern u8 net_server_ethaddr[ARP_HLEN]; /* Boot server enet address */
> @@ -504,8 +506,8 @@ extern ushort net_native_vlan; /* Our Native VLAN */
> extern int net_restart_wrap; /* Tried all network devices */
>
> enum proto_t {
> - BOOTP, RARP, ARP, TFTPGET, DHCP, PING, PING6, DNS, NFS, CDP, NETCONS,
> - SNTP, TFTPSRV, TFTPPUT, LINKLOCAL, FASTBOOT, WOL, UDP, NCSI, WGET
> + BOOTP, RARP, ARP, TFTPGET, DHCP, DHCP6, PING, PING6, DNS, NFS, CDP,
> + NETCONS, SNTP, TFTPSRV, TFTPPUT, LINKLOCAL, FASTBOOT, WOL, UDP, NCSI, WGET
> };
>
> extern char net_boot_file_name[1024];/* Boot File name */
> diff --git a/net/Makefile b/net/Makefile
> index bea000b206..5968110170 100644
> --- a/net/Makefile
> +++ b/net/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_IPV6) += net6.o
> obj-$(CONFIG_CMD_NFS) += nfs.o
> obj-$(CONFIG_CMD_PING) += ping.o
> obj-$(CONFIG_CMD_PING6) += ping6.o
> +obj-$(CONFIG_CMD_DHCP6) += dhcpv6.o
> obj-$(CONFIG_CMD_PCAP) += pcap.o
> obj-$(CONFIG_CMD_RARP) += rarp.o
> obj-$(CONFIG_CMD_SNTP) += sntp.o
> diff --git a/net/dhcpv6.c b/net/dhcpv6.c
> new file mode 100644
> index 0000000000..0d1c600632
> --- /dev/null
> +++ b/net/dhcpv6.c
> @@ -0,0 +1,719 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) Microsoft Corporation
> + * Author: Sean Edmond <seanedmond@microsoft.com>
> + *
> + */
> +
> +/* Simple DHCP6 network layer implementation. */
> +
> +#include <common.h>
> +#include <net6.h>
> +#include <malloc.h>
> +#include <linux/delay.h>
> +#include "net_rand.h"
> +#include "dhcpv6.h"
> +
> +#define PORT_DHCP6_S 547 /* DHCP6 server UDP port */
> +#define PORT_DHCP6_C 546 /* DHCP6 client UDP port */
> +
> +/* default timeout parameters (in ms) */
> +#define SOL_MAX_DELAY_MS 1000
> +#define SOL_TIMEOUT_MS 1000
> +#define SOL_MAX_RT_MS 3600000
> +#define REQ_TIMEOUT_MS 1000
> +#define REQ_MAX_RT_MS 30000
> +#define REQ_MAX_RC 10
> +#define MAX_WAIT_TIME_MS 60000
> +
> +/* global variable to track any updates from DHCP6 server */
> +int updated_sol_max_rt_ms = SOL_MAX_RT_MS;
> +/* state machine parameters/variables */
> +struct dhcp6_sm_params sm_params;
> +
> +static void dhcp6_state_machine(bool timeout, uchar *rx_pkt, unsigned int len);
> +
> +/* Handle DHCP received packets (set as UDP handler) */
> +static void dhcp6_handler(uchar *pkt, unsigned int dest, struct in_addr sip,
> + unsigned int src, unsigned int len)
> +{
> + /* return if ports don't match DHCPv6 ports */
> + if (dest != PORT_DHCP6_C || src != PORT_DHCP6_S)
> + return;
> +
> + dhcp6_state_machine(false, pkt, len);
> +}
> +
> +/**
> + * dhcp6_add_option() - Adds DHCP6 option to a packet
> + * @option_id: The option ID to add (See DHCP6_OPTION_* definitions)
> + * @pkt: A pointer to the current write location of the TX packet
> + *
> + * Return: The number of bytes written into "*pkt"
> + */
> +static int dhcp6_add_option(int option_id, uchar *pkt)
> +{
> + struct dhcp6_option_duid_ll *duid_opt;
> + struct dhcp6_option_elapsed_time *elapsed_time_opt;
> + struct dhcp6_option_ia_ta *ia_ta_opt;
> + struct dhcp6_option_ia_na *ia_na_opt;
> + struct dhcp6_option_oro *oro_opt;
> + struct dhcp6_option_client_arch *client_arch_opt;
> + struct dhcp6_option_vendor_class *vendor_class_opt;
> + int opt_len;
> + long elapsed_time;
> + size_t vci_strlen;
> + int num_oro = 0;
> + int num_client_arch = 0;
> + int num_vc_data = 0;
> + struct dhcp6_option_hdr *dhcp_option = (struct dhcp6_option_hdr *)pkt;
> + uchar *dhcp_option_start = pkt + sizeof(struct dhcp6_option_hdr);
> +
> + dhcp_option->option_id = htons(option_id);
> +
> + switch (option_id) {
> + case DHCP6_OPTION_CLIENTID:
> + /* Only support for DUID-LL in Client ID option for now */
> + duid_opt = (struct dhcp6_option_duid_ll *)dhcp_option_start;
> + duid_opt->duid_type = htons(DUID_TYPE_LL);
> + duid_opt->hw_type = htons(DUID_HW_TYPE_ENET);
> + memcpy(duid_opt->ll_addr, net_ethaddr, ETH_ALEN);
> + opt_len = sizeof(struct dhcp6_option_duid_ll) + ETH_ALEN;
> +
> + /* Save DUID for comparison later */
> + memcpy(sm_params.duid, duid_opt, opt_len);
> + break;
> + case DHCP6_OPTION_ELAPSED_TIME:
> + /* calculate elapsed time in 1/100th of a second */
> + elapsed_time = (sm_params.dhcp6_retry_ms -
> + sm_params.dhcp6_start_ms) / 10;
> + if (elapsed_time > 0xFFFF)
> + elapsed_time = 0xFFFF;
> +
> + elapsed_time_opt = (struct dhcp6_option_elapsed_time *)dhcp_option_start;
> + elapsed_time_opt->elapsed_time = htons(elapsed_time);
> +
> + opt_len = sizeof(struct dhcp6_option_elapsed_time);
> + break;
> + case DHCP6_OPTION_IA_TA:
> + ia_ta_opt = (struct dhcp6_option_ia_ta *)dhcp_option_start;
> + ia_ta_opt->iaid = htonl(sm_params.ia_id);
> +
> + opt_len = sizeof(struct dhcp6_option_ia_ta);
> + break;
> + case DHCP6_OPTION_IA_NA:
> + ia_na_opt = (struct dhcp6_option_ia_na *)dhcp_option_start;
> + ia_na_opt->iaid = htonl(sm_params.ia_id);
> + /* In a message sent by a client to a server,
> + * the T1 and T2 fields SHOULD be set to 0
> + */
> + ia_na_opt->t1 = 0;
> + ia_na_opt->t2 = 0;
> +
> + opt_len = sizeof(struct dhcp6_option_ia_na);
> + break;
> + case DHCP6_OPTION_ORO:
> + oro_opt = (struct dhcp6_option_oro *)dhcp_option_start;
> + oro_opt->req_option_code[num_oro++] = htons(DHCP6_OPTION_OPT_BOOTFILE_URL);
> + oro_opt->req_option_code[num_oro++] = htons(DHCP6_OPTION_SOL_MAX_RT);
> + if (IS_ENABLED(CONFIG_DHCP6_PXE_DHCP_OPTION)) {
> + oro_opt->req_option_code[num_oro++] =
> + htons(DHCP6_OPTION_OPT_BOOTFILE_PARAM);
> + }
> +
> + opt_len = sizeof(__be16) * num_oro;
> + break;
> + case DHCP6_OPTION_CLIENT_ARCH_TYPE:
> + client_arch_opt = (struct dhcp6_option_client_arch *)dhcp_option_start;
> + client_arch_opt->arch_type[num_client_arch++] = htons(CONFIG_DHCP6_PXE_CLIENTARCH);
> +
> + opt_len = sizeof(__be16) * num_client_arch;
> + break;
> + case DHCP6_OPTION_VENDOR_CLASS:
> + vendor_class_opt = (struct dhcp6_option_vendor_class *)dhcp_option_start;
> + vendor_class_opt->enterprise_number = htonl(CONFIG_DHCP6_ENTERPRISE_ID);
> +
> + vci_strlen = strlen(DHCP6_VCI_STRING);
> + vendor_class_opt->vendor_class_data[num_vc_data].vendor_class_len =
> + htons(vci_strlen);
> + memcpy(vendor_class_opt->vendor_class_data[num_vc_data].opaque_data,
> + DHCP6_VCI_STRING, vci_strlen);
> + num_vc_data++;
> +
> + opt_len = sizeof(struct dhcp6_option_vendor_class) +
> + sizeof(struct vendor_class_data) * num_vc_data +
> + vci_strlen;
> + break;
> + case DHCP6_OPTION_NII:
> + dhcp_option_start[0] = 1;
> + dhcp_option_start[1] = 0;
> + dhcp_option_start[2] = 0;
> +
> + opt_len = 3;
> + break;
> + default:
> + printf("***Warning unknown DHCP6 option %d. Not adding to message\n", option_id);
> + return 0;
> + }
> + dhcp_option->option_len = htons(opt_len);
> +
> + return opt_len + sizeof(struct dhcp6_option_hdr);
> +}
> +
> +/**
> + * dhcp6_send_solicit_packet() - Send a SOLICIT packet
> + *
> + * Implements RFC 8415:
> + * - 16.2. Solicit Message
> + * - 18.2.1. Creation and Transmission of Solicit Messages
> + *
> + * Adds DHCP6 header and DHCP6 options. Sends the UDP packet
> + * and sets the UDP handler.
> + */
> +static void dhcp6_send_solicit_packet(void)
> +{
> + struct in6_addr dhcp_bcast_ip6;
> + int len = 0;
> + uchar *pkt;
> + uchar *dhcp_pkt_start_ptr;
> + struct dhcp6_hdr *dhcp_hdr;
> +
> + pkt = net_tx_packet + net_eth_hdr_size() + IP6_HDR_SIZE + UDP_HDR_SIZE;
> + dhcp_pkt_start_ptr = pkt;
> +
> + /* Add the DHCP6 header */
> + dhcp_hdr = (struct dhcp6_hdr *)pkt;
> + dhcp_hdr->msg_type = DHCP6_MSG_SOLICIT;
> + dhcp_hdr->trans_id = htons(sm_params.trans_id);
> + pkt += sizeof(struct dhcp6_hdr);
> +
> + /* Add the options */
> + pkt += dhcp6_add_option(DHCP6_OPTION_CLIENTID, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_ELAPSED_TIME, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_IA_NA, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_ORO, pkt);
> + if (CONFIG_DHCP6_PXE_CLIENTARCH != 0xFF)
> + pkt += dhcp6_add_option(DHCP6_OPTION_CLIENT_ARCH_TYPE, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_VENDOR_CLASS, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_NII, pkt);
> +
> + /* calculate packet length */
> + len = pkt - dhcp_pkt_start_ptr;
> +
> + /* send UDP packet to DHCP6 multicast address */
> + string_to_ip6(DHCP6_MULTICAST_ADDR, sizeof(DHCP6_MULTICAST_ADDR), &dhcp_bcast_ip6);
> + net_set_udp_handler(dhcp6_handler);
> + net_send_udp_packet6((uchar *)net_bcast_ethaddr, &dhcp_bcast_ip6,
> + PORT_DHCP6_S, PORT_DHCP6_C, len);
> +}
> +
> +/**
> + * dhcp6_send_request_packet() - Send a REQUEST packet
> + *
> + * * Implements RFC 8415:
> + * - 16.4. Request Message
> + * - 18.2.2. Creation and Transmission of Request Messages
> + *
> + * Adds DHCP6 header and DHCP6 options. Sends the UDP packet
> + * and sets the UDP handler.
> + */
> +static void dhcp6_send_request_packet(void)
> +{
> + struct in6_addr dhcp_bcast_ip6;
> + int len = 0;
> + uchar *pkt;
> + uchar *dhcp_pkt_start_ptr;
> + struct dhcp6_hdr *dhcp_hdr;
> +
> + pkt = net_tx_packet + net_eth_hdr_size() + IP6_HDR_SIZE + UDP_HDR_SIZE;
> + dhcp_pkt_start_ptr = pkt;
> +
> + /* Add the DHCP6 header */
> + dhcp_hdr = (struct dhcp6_hdr *)pkt;
> + dhcp_hdr->msg_type = DHCP6_MSG_REQUEST;
> + dhcp_hdr->trans_id = htons(sm_params.trans_id);
> + pkt += sizeof(struct dhcp6_hdr);
> +
> + /* add the options */
> + pkt += dhcp6_add_option(DHCP6_OPTION_CLIENTID, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_ELAPSED_TIME, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_IA_NA, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_ORO, pkt);
> + /* copy received IA_TA/IA_NA into the REQUEST packet */
> + if (sm_params.server_uid.uid_ptr) {
> + memcpy(pkt, sm_params.server_uid.uid_ptr, sm_params.server_uid.uid_size);
> + pkt += sm_params.server_uid.uid_size;
> + }
> + if (CONFIG_DHCP6_PXE_CLIENTARCH != 0xFF)
> + pkt += dhcp6_add_option(DHCP6_OPTION_CLIENT_ARCH_TYPE, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_VENDOR_CLASS, pkt);
> + pkt += dhcp6_add_option(DHCP6_OPTION_NII, pkt);
> +
> + /* calculate packet length */
> + len = pkt - dhcp_pkt_start_ptr;
> +
> + /* send UDP packet to DHCP6 multicast address */
> + string_to_ip6(DHCP6_MULTICAST_ADDR, strlen(DHCP6_MULTICAST_ADDR), &dhcp_bcast_ip6);
> + net_set_udp_handler(dhcp6_handler);
> + net_send_udp_packet6((uchar *)net_bcast_ethaddr, &dhcp_bcast_ip6,
> + PORT_DHCP6_S, PORT_DHCP6_C, len);
> +}
> +
> +static void dhcp6_parse_ia_options(struct dhcp6_option_hdr *ia_ptr, uchar *ia_option_ptr)
> +{
> + struct dhcp6_option_hdr *ia_option_hdr;
> +
> + ia_option_hdr = (struct dhcp6_option_hdr *)ia_option_ptr;
> +
> + /* Search for options encapsulated in IA_NA/IA_TA (DHCP6_OPTION_IAADDR
> + * or DHCP6_OPTION_STATUS_CODE)
> + */
> + while (ia_option_ptr < ((uchar *)ia_ptr + ntohs(ia_ptr->option_len))) {
> + switch (ntohs(ia_option_hdr->option_id)) {
> + case DHCP6_OPTION_IAADDR:
> + sm_params.rx_status.ia_addr_found = true;
> + net_copy_ip6(&sm_params.rx_status.ia_addr_ipv6,
> + (ia_option_ptr + sizeof(struct dhcp6_hdr)));
> + debug("DHCP6_OPTION_IAADDR FOUND\n");
> + break;
> + case DHCP6_OPTION_STATUS_CODE:
> + sm_params.rx_status.ia_status_code =
> + ntohs(*((u16 *)(ia_option_ptr + sizeof(struct dhcp6_hdr))));
> + printf("ERROR : IA STATUS %d\n", sm_params.rx_status.ia_status_code);
> + break;
> + default:
> + debug("Unknown Option in IA, skipping\n");
> + break;
> + }
> +
> + ia_option_ptr += ntohs(((struct dhcp6_option_hdr *)ia_option_ptr)->option_len);
> + }
> +}
> +
> +/**
> + * dhcp6_parse_options() - Parse the DHCP6 options
> + *
> + * @rx_pkt: pointer to beginning of received DHCP6 packet
> + * @len: Total length of the DHCP6 packet
> + *
> + * Parses the DHCP options from a received DHCP packet. Perform error checking
> + * on the options received. Any relevant status is available in:
> + * "sm_params.rx_status"
> + *
> + */
> +static void dhcp6_parse_options(uchar *rx_pkt, unsigned int len)
> +{
> + uchar *option_ptr;
> + int sol_max_rt_sec, option_len;
> + char *s, *e;
> + struct dhcp6_option_hdr *option_hdr;
> +
> + memset(&sm_params.rx_status, 0, sizeof(struct dhcp6_rx_pkt_status));
> +
> + option_hdr = (struct dhcp6_option_hdr *)(rx_pkt + sizeof(struct dhcp6_hdr));
> + /* check that required options exist */
> + while (option_hdr < (struct dhcp6_option_hdr *)(rx_pkt + len)) {
> + option_ptr = ((uchar *)option_hdr) + sizeof(struct dhcp6_hdr);
> + option_len = ntohs(option_hdr->option_len);
> +
> + switch (ntohs(option_hdr->option_id)) {
> + case DHCP6_OPTION_CLIENTID:
> + if (memcmp(option_ptr, sm_params.duid, option_len)
> + != 0) {
> + debug("CLIENT ID DOESN'T MATCH\n");
> + } else {
> + debug("CLIENT ID FOUND and MATCHES\n");
> + sm_params.rx_status.client_id_match = true;
> + }
> + break;
> + case DHCP6_OPTION_SERVERID:
> + sm_params.rx_status.server_id_found = true;
> + sm_params.rx_status.server_uid_ptr = (uchar *)option_hdr;
> + sm_params.rx_status.server_uid_size = option_len +
> + sizeof(struct dhcp6_option_hdr);
> + debug("SERVER ID FOUND\n");
> + break;
> + case DHCP6_OPTION_IA_TA:
> + case DHCP6_OPTION_IA_NA:
> + /* check the IA_ID */
> + if (*((u32 *)option_ptr) != htonl(sm_params.ia_id)) {
> + debug("IA_ID mismatch 0x%08x 0x%08x\n",
> + *((u32 *)option_ptr), htonl(sm_params.ia_id));
> + break;
> + }
> +
> + if (ntohs(option_hdr->option_id) == DHCP6_OPTION_IA_NA) {
> + /* skip past IA_ID/T1/T2 */
> + option_ptr += 3 * sizeof(u32);
> + } else if (ntohs(option_hdr->option_id) == DHCP6_OPTION_IA_TA) {
> + /* skip past IA_ID */
> + option_ptr += sizeof(u32);
> + }
> + /* parse the IA_NA/IA_TA encapsulated options */
> + dhcp6_parse_ia_options(option_hdr, option_ptr);
> + break;
> + case DHCP6_OPTION_STATUS_CODE:
> + debug("DHCP6_OPTION_STATUS_CODE FOUND\n");
> + sm_params.rx_status.status_code = ntohs(*((u16 *)option_ptr));
> + debug("DHCP6 top-level status code %d\n", sm_params.rx_status.status_code);
> + debug("DHCP6 status message: %.*s\n", len, option_ptr + 2);
> + break;
> + case DHCP6_OPTION_SOL_MAX_RT:
> + debug("DHCP6_OPTION_SOL_MAX_RT FOUND\n");
> + sol_max_rt_sec = ntohl(*((u32 *)option_ptr));
> +
> + /* A DHCP client MUST ignore any SOL_MAX_RT option values that are less
> + * than 60 or more than 86400
> + */
> + if (sol_max_rt_sec >= 60 && sol_max_rt_sec <= 86400) {
> + updated_sol_max_rt_ms = sol_max_rt_sec * 1000;
> + if (sm_params.curr_state == DHCP6_SOLICIT)
> + sm_params.mrt_ms = updated_sol_max_rt_ms;
> + }
> + break;
> + case DHCP6_OPTION_OPT_BOOTFILE_URL:
> + debug("DHCP6_OPTION_OPT_BOOTFILE_URL FOUND\n");
> + copy_filename(net_boot_file_name, option_ptr, option_len + 1);
> + debug("net_boot_file_name: %s\n", net_boot_file_name);
> +
> + /* copy server_ip6 (required for PXE) */
> + s = strchr(net_boot_file_name, '[');
> + e = strchr(net_boot_file_name, ']');
> + if (s && e && e > s)
> + string_to_ip6(s + 1, e - s - 1, &net_server_ip6);
> + break;
> + case DHCP6_OPTION_OPT_BOOTFILE_PARAM:
> + if (IS_ENABLED(CONFIG_DHCP6_PXE_DHCP_OPTION)) {
> + debug("DHCP6_OPTION_OPT_BOOTFILE_PARAM FOUND\n");
> +
> + if (pxelinux_configfile)
> + free(pxelinux_configfile);
> +
> + pxelinux_configfile = (char *)malloc((option_len + 1) *
> + sizeof(char));
> + if (pxelinux_configfile)
> + strlcpy(pxelinux_configfile, option_ptr, option_len + 1);
> + else
> + printf("Error: Failed to allocate pxelinux_configfile\n");
> +
> + debug("PXE CONFIG FILE %s\n", pxelinux_configfile);
> + }
> + break;
> + case DHCP6_OPTION_PREFERENCE:
> + debug("DHCP6_OPTION_PREFERENCE FOUND\n");
> + sm_params.rx_status.preference = *option_ptr;
> + break;
> + default:
> + debug("Unknown Option ID: %d, skipping parsing\n",
> + ntohs(option_hdr->option_id));
> + break;
> + }
> + /* Increment to next option header */
> + option_hdr = (struct dhcp6_option_hdr *)(((uchar *)option_hdr) +
> + sizeof(struct dhcp6_option_hdr) + option_len);
> + }
> +}
> +
> +/**
> + * dhcp6_check_advertise_packet() - Perform error checking on an expected
> + * ADVERTISE packet.
> + *
> + * @rx_pkt: pointer to beginning of received DHCP6 packet
> + * @len: Total length of the DHCP6 packet
> + *
> + * Implements RFC 8415:
> + * - 16.3. Advertise Message
> + * - 18.2.10. Receipt of Reply Messages
> + *
> + * Return : 0 : ADVERTISE packet was received with no errors.
> + * State machine can progress
> + * 1 : - packet received is not an ADVERTISE packet
> + * - there were errors in the packet received,
> + * - this is the first SOLICIT packet, but
> + * received preference is not 255, so we have
> + * to wait for more server responses.
> + */
> +static int dhcp6_check_advertise_packet(uchar *rx_pkt, unsigned int len)
> +{
> + u16 rx_uid_size;
> + struct dhcp6_hdr *dhcp6_hdr = (struct dhcp6_hdr *)rx_pkt;
> +
> + /* Ignore message if msg-type != advertise */
> + if (dhcp6_hdr->msg_type != DHCP6_MSG_ADVERTISE)
> + return 1;
> + /* Ignore message if transaction ID doesn't match */
> + if (dhcp6_hdr->trans_id != htons(sm_params.trans_id))
> + return 1;
> +
> + dhcp6_parse_options(rx_pkt, len);
> +
> + /* Ignore advertise if any of these conditions met */
> + if (!sm_params.rx_status.server_id_found ||
> + !sm_params.rx_status.client_id_match ||
> + sm_params.rx_status.status_code != DHCP6_SUCCESS) {
> + return 1;
> + }
> +
> + if (sm_params.rx_status.server_id_found) {
> + /* if no server UID has been received yet, or if the server UID
> + * received has a higher preference value than the currently saved
> + * server UID, save the new server UID and preference
> + */
> + if (!sm_params.server_uid.uid_ptr ||
> + (sm_params.server_uid.uid_ptr &&
> + sm_params.server_uid.preference < sm_params.rx_status.preference)) {
> + rx_uid_size = sm_params.rx_status.server_uid_size;
> + if (sm_params.server_uid.uid_ptr)
> + free(sm_params.server_uid.uid_ptr);
> + sm_params.server_uid.uid_ptr = malloc(rx_uid_size * sizeof(uchar));
> + if (sm_params.server_uid.uid_ptr)
> + memcpy(sm_params.server_uid.uid_ptr,
> + sm_params.rx_status.server_uid_ptr, rx_uid_size);
> +
> + sm_params.server_uid.uid_size = rx_uid_size;
> + sm_params.server_uid.preference = sm_params.rx_status.preference;
> + }
> +
> + /* If the first SOLICIT and preference code is 255, use right away.
> + * Otherwise, wait for the first SOLICIT period for more
> + * DHCP6 servers to respond.
> + */
> + if (sm_params.retry_cnt == 1 &&
> + sm_params.server_uid.preference != 255) {
> + debug("valid ADVERTISE, waiting for first SOLICIT period\n");
> + return 1;
> + }
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * dhcp6_check_reply_packet() - Perform error checking on an expected
> + * REPLY packet.
> + *
> + * @rx_pkt: pointer to beginning of received DHCP6 packet
> + * @len: Total length of the DHCP6 packet
> + *
> + * Implements RFC 8415:
> + * - 16.10. Reply Message
> + * - 18.2.10. Receipt of Reply Messages
> + *
> + * Return : 0 - REPLY packet was received with no errors
> + * 1 - packet received is not an REPLY packet,
> + * or there were errors in the packet received
> + */
> +static int dhcp6_check_reply_packet(uchar *rx_pkt, unsigned int len)
> +{
> + struct dhcp6_hdr *dhcp6_hdr = (struct dhcp6_hdr *)rx_pkt;
> +
> + /* Ignore message if msg-type != reply */
> + if (dhcp6_hdr->msg_type != DHCP6_MSG_REPLY)
> + return 1;
> + /* check that transaction ID matches */
> + if (dhcp6_hdr->trans_id != htons(sm_params.trans_id))
> + return 1;
> +
> + dhcp6_parse_options(rx_pkt, len);
> +
> + /* if no addresses found, restart DHCP */
> + if (!sm_params.rx_status.ia_addr_found ||
> + sm_params.rx_status.ia_status_code == DHCP6_NO_ADDRS_AVAIL ||
> + sm_params.rx_status.status_code == DHCP6_NOT_ON_LINK) {
> + /* restart DHCP */
> + debug("No address found in reply. Restarting DHCP\n");
> + dhcp6_start();
> + }
> +
> + /* ignore reply if any of these conditions met */
> + if (!sm_params.rx_status.server_id_found ||
> + !sm_params.rx_status.client_id_match ||
> + sm_params.rx_status.status_code == DHCP6_UNSPEC_FAIL) {
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +/* Timeout for DHCP6 SOLICIT/REQUEST */
> +static void dhcp6_timeout_handler(void)
> +{
> + /* call state machine with the timeout flag */
> + dhcp6_state_machine(true, NULL, 0);
> +}
> +
> +/**
> + * dhcp6_state_machine() - DHCP6 state machine
> + *
> + * @timeout: TRUE : timeout waiting for response from
> + * DHCP6 server
> + * FALSE : init or received response from DHCP6 server
> + * @rx_pkt: Pointer to the beginning of received DHCP6 packet.
> + * Will be NULL if called as part of init
> + * or timeout==TRUE
> + * @len: Total length of the DHCP6 packet if rx_pkt != NULL
> + *
> + * Implements RFC 8415:
> + * - 5.2. Client/Server Exchanges Involving Four Messages
> + * - 15. Reliability of Client-Initiated Message Exchanges
> + *
> + * Handles:
> + * - transmission of SOLICIT and REQUEST packets
> + * - retransmission of SOLICIT and REQUEST packets if no
> + * response is received within the timeout window
> + * - checking received ADVERTISE and REPLY packets to
> + * assess if the DHCP state machine can progress
> + */
> +static void dhcp6_state_machine(bool timeout, uchar *rx_pkt, unsigned int len)
> +{
> + int rand_minus_plus_100;
> +
> + switch (sm_params.curr_state) {
> + case DHCP6_INIT:
> + sm_params.next_state = DHCP6_SOLICIT;
> + break;
> + case DHCP6_SOLICIT:
> + if (!timeout) {
> + /* check the rx packet and determine if we can transition to next
> + * state.
> + */
> + if (dhcp6_check_advertise_packet(rx_pkt, len))
> + return;
> +
> + debug("ADVERTISE good, transition to REQUEST\n");
> + sm_params.next_state = DHCP6_REQUEST;
> + } else if (sm_params.retry_cnt == 1) {
> + /* If a server UID was received in the first SOLICIT period
> + * transition to REQUEST
> + */
> + if (sm_params.server_uid.uid_ptr)
> + sm_params.next_state = DHCP6_REQUEST;
> + }
> + break;
> + case DHCP6_REQUEST:
> + if (!timeout) {
> + /* check the rx packet and determine if we can transition to next state */
> + if (dhcp6_check_reply_packet(rx_pkt, len))
> + return;
> +
> + debug("REPLY good, transition to DONE\n");
> + sm_params.next_state = DHCP6_DONE;
> + }
> + break;
> + case DHCP6_DONE:
> + case DHCP6_FAIL:
> + /* Shouldn't get here, as state machine should exit
> + * immediately when DHCP6_DONE or DHCP6_FAIL is entered.
> + * Proceed anyway to proceed DONE/FAIL actions
> + */
> + debug("Unexpected DHCP6 state : %d\n", sm_params.curr_state);
> + break;
> + }
> + /* re-seed the RNG */
> + srand(get_ticks() + rand());
> +
> + /* handle state machine entry conditions */
> + if (sm_params.curr_state != sm_params.next_state) {
> + sm_params.retry_cnt = 0;
> +
> + if (sm_params.next_state == DHCP6_SOLICIT) {
> + /* delay a random ammount (special for SOLICIT) */
> + udelay((rand() % SOL_MAX_DELAY_MS) * 1000);
> + /* init timestamp variables after SOLICIT delay */
> + sm_params.dhcp6_start_ms = get_timer(0);
> + sm_params.dhcp6_retry_start_ms = sm_params.dhcp6_start_ms;
> + sm_params.dhcp6_retry_ms = sm_params.dhcp6_start_ms;
> + /* init transaction and ia_id */
> + sm_params.trans_id = rand() & 0xFFFFFF;
> + sm_params.ia_id = rand();
> + /* initialize retransmission parameters */
> + sm_params.irt_ms = SOL_TIMEOUT_MS;
> + sm_params.mrt_ms = updated_sol_max_rt_ms;
> + /* RFCs default MRC is be 0 (try infinitely)
> + * give up after CONFIG_NET_RETRY_COUNT number of tries (same as DHCPv4)
> + */
> + sm_params.mrc = CONFIG_NET_RETRY_COUNT;
> + sm_params.mrd_ms = 0;
> +
> + } else if (sm_params.next_state == DHCP6_REQUEST) {
> + /* init timestamp variables */
> + sm_params.dhcp6_retry_start_ms = get_timer(0);
> + sm_params.dhcp6_retry_ms = sm_params.dhcp6_start_ms;
> + /* initialize retransmission parameters */
> + sm_params.irt_ms = REQ_TIMEOUT_MS;
> + sm_params.mrt_ms = REQ_MAX_RT_MS;
> + sm_params.mrc = REQ_MAX_RC;
> + sm_params.mrd_ms = 0;
> + }
> + }
> +
> + if (timeout)
> + sm_params.dhcp6_retry_ms = get_timer(0);
> +
> + /* Check if MRC or MRD have been passed */
> + if ((sm_params.mrc != 0 &&
> + sm_params.retry_cnt >= sm_params.mrc) ||
> + (sm_params.mrd_ms != 0 &&
> + ((sm_params.dhcp6_retry_ms - sm_params.dhcp6_retry_start_ms) >= sm_params.mrd_ms))) {
> + sm_params.next_state = DHCP6_FAIL;
> + }
> +
> + /* calculate retransmission timeout (RT) */
> + rand_minus_plus_100 = ((rand() % 200) - 100);
> + if (sm_params.retry_cnt == 0) {
> + sm_params.rt_ms = sm_params.irt_ms +
> + ((sm_params.irt_ms * rand_minus_plus_100) / 1000);
> + } else {
> + sm_params.rt_ms = (2 * sm_params.rt_prev_ms) +
> + ((sm_params.rt_prev_ms * rand_minus_plus_100) / 1000);
> + }
> +
> + if (sm_params.rt_ms > sm_params.mrt_ms) {
> + sm_params.rt_ms = sm_params.mrt_ms +
> + ((sm_params.mrt_ms * rand_minus_plus_100) / 1000);
> + }
> +
> + sm_params.rt_prev_ms = sm_params.rt_ms;
> +
> + net_set_timeout_handler(sm_params.rt_ms, dhcp6_timeout_handler);
> +
> + /* send transmit/retransmit message or fail */
> + sm_params.curr_state = sm_params.next_state;
> +
> + if (sm_params.curr_state == DHCP6_SOLICIT) {
> + /* send solicit packet */
> + dhcp6_send_solicit_packet();
> + printf("DHCP6 SOLICIT %d\n", sm_params.retry_cnt);
> + } else if (sm_params.curr_state == DHCP6_REQUEST) {
> + /* send request packet */
> + dhcp6_send_request_packet();
> + printf("DHCP6 REQUEST %d\n", sm_params.retry_cnt);
> + } else if (sm_params.curr_state == DHCP6_DONE) {
> + net_set_timeout_handler(0, NULL);
> +
> + /* Duplicate address detection (DAD) should be
> + * performed here before setting net_ip6
> + * (enhancement should be considered)
> + */
> + net_copy_ip6(&net_ip6, &sm_params.rx_status.ia_addr_ipv6);
> + printf("DHCP6 client bound to %pI6c\n", &net_ip6);
> + /* will load with TFTP6 */
> + net_auto_load();
> + } else if (sm_params.curr_state == DHCP6_FAIL) {
> + printf("DHCP6 FAILED, TERMINATING\n");
> + net_set_state(NETLOOP_FAIL);
> + }
> + sm_params.retry_cnt++;
> +}
> +
> +/* Start or restart DHCP6 */
> +void dhcp6_start(void)
> +{
> + memset(&sm_params, 0, sizeof(struct dhcp6_sm_params));
> +
> + /* seed the RNG with MAC address */
> + srand_mac();
> +
> + sm_params.curr_state = DHCP6_INIT;
> + dhcp6_state_machine(false, NULL, 0);
> +}
> diff --git a/net/dhcpv6.h b/net/dhcpv6.h
> new file mode 100644
> index 0000000000..80ca520432
> --- /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__ */
> diff --git a/net/net.c b/net/net.c
> index c9a749f6cc..8cb8b4b9f3 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -107,6 +107,8 @@
> #include <watchdog.h>
> #include <linux/compiler.h>
> #include <test/test.h>
> +#include <net/tcp.h>
> +#include <net/wget.h>
> #include "arp.h"
> #include "bootp.h"
> #include "cdp.h"
> @@ -120,8 +122,7 @@
> #if defined(CONFIG_CMD_WOL)
> #include "wol.h"
> #endif
> -#include <net/tcp.h>
> -#include <net/wget.h>
> +#include "dhcpv6.h"
>
> /** BOOTP EXTENTIONS **/
>
> @@ -135,6 +136,8 @@ struct in_addr net_dns_server;
> /* Our 2nd DNS IP address */
> struct in_addr net_dns_server2;
> #endif
> +/* Indicates whether the pxe path prefix / config file was specified in dhcp option */
> +char *pxelinux_configfile;
>
> /** END OF BOOTP EXTENTIONS **/
>
> @@ -510,6 +513,10 @@ restart:
> dhcp_request(); /* Basically same as BOOTP */
> break;
> #endif
> + case DHCP6:
> + if (IS_ENABLED(CONFIG_CMD_DHCP6))
> + dhcp6_start();
> + break;
> #if defined(CONFIG_CMD_BOOTP)
> case BOOTP:
> bootp_reset();
> --
> 2.40.0
>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>