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u-boot/net/dhcpv6.c
Sean Edmond 1b3117db3e net: ipv6: Fix CID 453851 and CID 436278 
CID 453851 : sprintf() shouldn't copy from/to tmp
CID 436278 : DHCP6 option_len should be checked before use

Signed-off-by: Sean Edmond <seanedmond@microsoft.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
2023-06-14 15:48:45 -04:00

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// 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);
if (option_ptr + option_len > rx_pkt + len) {
debug("Invalid option length\n");
return;
}
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);
}
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