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barebox/net/dhcp.c

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/*
* Based on LiMon - BOOTP.
*
* Copyright 1994, 1995, 2000 Neil Russell.
* (See License)
* Copyright 2000 Roland Borde
* Copyright 2000 Paolo Scaffardi
* Copyright 2000-2004 Wolfgang Denk, wd@denx.de
*/
#include <common.h>
#include <command.h>
#include <complete.h>
#include <environment.h>
#include <clock.h>
#include <net.h>
#include <libbb.h>
#include <errno.h>
#include <magicvar.h>
#include <linux/err.h>
#include <getopt.h>
#include <globalvar.h>
#include <init.h>
#define DHCP_DEFAULT_RETRY 20
#define OPT_SIZE 312 /* Minimum DHCP Options size per RFC2131 - results in 576 byte pkt */
struct bootp {
uint8_t bp_op; /* Operation */
#define OP_BOOTREQUEST 1
#define OP_BOOTREPLY 2
uint8_t bp_htype; /* Hardware type */
#define HWT_ETHER 1
uint8_t bp_hlen; /* Hardware address length */
#define HWL_ETHER 6
uint8_t bp_hops; /* Hop count (gateway thing) */
uint32_t bp_id; /* Transaction ID */
uint16_t bp_secs; /* Seconds since boot */
uint16_t bp_spare1; /* Alignment */
IPaddr_t bp_ciaddr; /* Client IP address */
IPaddr_t bp_yiaddr; /* Your (client) IP address */
IPaddr_t bp_siaddr; /* Server IP address */
IPaddr_t bp_giaddr; /* Gateway IP address */
uint8_t bp_chaddr[16]; /* Client hardware address */
char bp_sname[64]; /* Server host name */
char bp_file[128]; /* Boot file name */
char bp_vend[0]; /* Vendor information */
};
/* DHCP States */
typedef enum {
INIT,
INIT_REBOOT,
REBOOTING,
SELECTING,
REQUESTING,
REBINDING,
BOUND,
RENEWING,
} dhcp_state_t;
#define DHCP_DISCOVER 1
#define DHCP_OFFER 2
#define DHCP_REQUEST 3
#define DHCP_DECLINE 4
#define DHCP_ACK 5
#define DHCP_NAK 6
#define DHCP_RELEASE 7
#define BOOTP_VENDOR_MAGIC 0x63825363 /* RFC1048 Magic Cookie */
#define PORT_BOOTPS 67 /* BOOTP server UDP port */
#define PORT_BOOTPC 68 /* BOOTP client UDP port */
#define DHCP_MIN_EXT_LEN 64 /* minimal length of extension list */
static uint32_t Bootp_id;
static dhcp_state_t dhcp_state;
static uint32_t dhcp_leasetime;
static IPaddr_t net_dhcp_server_ip;
static uint64_t dhcp_start;
static char dhcp_tftpname[256];
static const char* dhcp_get_barebox_global(const char * var)
{
char * var_global = asprintf("global.dhcp.%s", var);
const char *val;
if (!var_global)
return NULL;
val = getenv(var_global);
free(var_global);
return val;
}
static int dhcp_set_barebox_global(const char * var, char *val)
{
char * var_global = asprintf("global.dhcp.%s", var);
int ret;
if (!var_global)
return -ENOMEM;
ret = setenv(var_global, val);
free(var_global);
return ret;
}
struct dhcp_opt {
unsigned char option;
/* request automatically the option when creating the DHCP request */
bool optional;
bool copy_only_if_valid;
const char *barebox_var_name;
const char *barebox_dhcp_global;
void (*handle)(struct dhcp_opt *opt, unsigned char *data, int tlen);
void *data;
struct bootp *bp;
};
static void netmask_handle(struct dhcp_opt *opt, unsigned char *popt, int optlen)
{
IPaddr_t ip;
ip = net_read_ip(popt);
net_set_netmask(ip);
}
static void gateway_handle(struct dhcp_opt *opt, unsigned char *popt, int optlen)
{
IPaddr_t ip;
ip = net_read_ip(popt);
net_set_gateway(ip);
}
static void env_ip_handle(struct dhcp_opt *opt, unsigned char *popt, int optlen)
{
IPaddr_t ip;
ip = net_read_ip(popt);
setenv_ip(opt->barebox_var_name, ip);
}
static void env_str_handle(struct dhcp_opt *opt, unsigned char *popt, int optlen)
{
char str[256];
char *tmp = str;
if (opt->data)
tmp = opt->data;
memcpy(tmp, popt, optlen);
tmp[optlen] = 0;
if (opt->copy_only_if_valid && !strlen(tmp))
return;
if (opt->barebox_var_name)
setenv(opt->barebox_var_name, tmp);
if (opt->barebox_dhcp_global)
dhcp_set_barebox_global(opt->barebox_dhcp_global, tmp);
}
static void copy_uint32_handle(struct dhcp_opt *opt, unsigned char *popt, int optlen)
{
net_copy_uint32(opt->data, (uint32_t *)popt);
};
static void copy_ip_handle(struct dhcp_opt *opt, unsigned char *popt, int optlen)
{
net_copy_ip(opt->data, popt);
};
static void bootfile_vendorex_handle(struct dhcp_opt *opt, unsigned char *popt, int optlen)
{
if (opt->bp->bp_file[0] != '\0')
return;
/*
* only use vendor boot file if we didn't
* receive a boot file in the main non-vendor
* part of the packet - god only knows why
* some vendors chose not to use this perfectly
* good spot to store the boot file (join on
* Tru64 Unix) it seems mind bogglingly crazy
* to me
*/
pr_warn("*** WARNING: using vendor optional boot file\n");
/*
* I can't use dhcp_vendorex_proc here because I need
* to write into the bootp packet - even then I had to
* pass the bootp packet pointer into here as the
* second arg
*/
env_str_handle(opt, popt, optlen);
}
struct dhcp_opt dhcp_options[] = {
{
.option = 1,
.handle = netmask_handle,
}, {
.option = 3,
.handle = gateway_handle,
}, {
.option = 6,
.handle = env_ip_handle,
.barebox_var_name = "net.nameserver",
}, {
.option = 12,
.copy_only_if_valid = 1,
.handle = env_str_handle,
.barebox_var_name = "global.hostname",
}, {
.option = 15,
.handle = env_str_handle,
.barebox_var_name = "net.domainname",
}, {
.option = 17,
.handle = env_str_handle,
.barebox_dhcp_global = "rootpath",
}, {
.option = 51,
.handle = copy_uint32_handle,
.data = &dhcp_leasetime,
}, {
.option = 54,
.handle = copy_ip_handle,
.data = &net_dhcp_server_ip,
.optional = true,
}, {
.option = 66,
.handle = env_str_handle,
.barebox_dhcp_global = "tftp_server_name",
.data = dhcp_tftpname,
}, {
.option = 67,
.handle = bootfile_vendorex_handle,
.barebox_dhcp_global = "bootfile",
}, {
.option = 224,
.handle = env_str_handle,
.barebox_dhcp_global = "oftree_file",
},
};
struct dhcp_param {
unsigned char option;
const char *barebox_var_name;
const char *barebox_dhcp_global;
int (*handle)(struct dhcp_param *param, u8 *e);
void *data;
};
static int dhcp_set_string_options(struct dhcp_param *param, u8 *e)
{
int str_len;
char* str = param->data;
if (!str && param->barebox_var_name)
str = (char*)getenv(param->barebox_var_name);
if (!str && param->barebox_dhcp_global)
str = (char*)dhcp_get_barebox_global(param->barebox_dhcp_global);
if (!str)
return 0;
str_len = strlen(str);
if (!str_len)
return 0;
*e++ = param->option;
*e++ = str_len;
memcpy(e, str, str_len);
return str_len + 2;
}
#define DHCP_HOSTNAME 12
#define DHCP_VENDOR_ID 60
#define DHCP_CLIENT_ID 61
#define DHCP_USER_CLASS 77
#define DHCP_CLIENT_UUID 97
struct dhcp_param dhcp_params[] = {
{
.option = DHCP_HOSTNAME,
.handle = dhcp_set_string_options,
.barebox_var_name = "global.hostname",
}, {
.option = DHCP_VENDOR_ID,
.handle = dhcp_set_string_options,
.barebox_dhcp_global = "vendor_id",
}, {
.option = DHCP_CLIENT_ID,
.handle = dhcp_set_string_options,
.barebox_dhcp_global = "client_id",
}, {
.option = DHCP_USER_CLASS,
.handle = dhcp_set_string_options,
.barebox_dhcp_global = "user_class",
}, {
.option = DHCP_CLIENT_UUID,
.handle = dhcp_set_string_options,
.barebox_dhcp_global = "client_uuid",
}
};
static void dhcp_set_param_data(int option, void* data)
{
struct dhcp_param *param;
int i;
for (i = 0; i < ARRAY_SIZE(dhcp_params); i++) {
param = &dhcp_params[i];
if (param->option == option) {
param->data = data;
return;
}
}
}
static int dhcp_set_ip_options(int option, u8 *e, IPaddr_t ip)
{
int tmp;
if (!ip)
return 0;
tmp = ntohl(ip);
*e++ = option;
*e++ = 4;
*e++ = tmp >> 24;
*e++ = tmp >> 16;
*e++ = tmp >> 8;
*e++ = tmp & 0xff;
return 6;
}
static int bootp_check_packet(unsigned char *pkt, unsigned src, unsigned len)
{
struct bootp *bp = (struct bootp *) pkt;
int retval = 0;
if (src != PORT_BOOTPS)
retval = -1;
else if (len < sizeof(struct bootp))
retval = -2;
else if (bp->bp_op != OP_BOOTREQUEST &&
bp->bp_op != OP_BOOTREPLY &&
bp->bp_op != DHCP_OFFER &&
bp->bp_op != DHCP_ACK &&
bp->bp_op != DHCP_NAK ) {
retval = -3;
}
else if (bp->bp_htype != HWT_ETHER)
retval = -4;
else if (bp->bp_hlen != HWL_ETHER)
retval = -5;
else if (net_read_uint32(&bp->bp_id) != Bootp_id) {
retval = -6;
}
debug("Filtering pkt = %d\n", retval);
return retval;
}
/*
* Copy parameters of interest from BOOTP_REPLY/DHCP_OFFER packet
*/
static void bootp_copy_net_params(struct bootp *bp)
{
IPaddr_t tmp_ip;
tmp_ip = net_read_ip(&bp->bp_yiaddr);
net_set_ip(tmp_ip);
tmp_ip = net_read_ip(&bp->bp_siaddr);
if (tmp_ip != 0)
net_set_serverip(tmp_ip);
if (strlen(bp->bp_file) > 0) {
setenv("bootfile", bp->bp_file);
dhcp_set_barebox_global("bootfile", bp->bp_file);
}
debug("bootfile: %s\n", bp->bp_file);
}
/*
* Initialize BOOTP extension fields in the request.
*/
static int dhcp_extended (u8 *e, int message_type, IPaddr_t ServerID,
IPaddr_t RequestedIP)
{
int i;
u8 *start = e;
u8 *cnt;
*e++ = 99; /* RFC1048 Magic Cookie */
*e++ = 130;
*e++ = 83;
*e++ = 99;
*e++ = 53; /* DHCP Message Type */
*e++ = 1;
*e++ = message_type;
*e++ = 57; /* Maximum DHCP Message Size */
*e++ = 2;
*e++ = (576 - 312 + OPT_SIZE) >> 8;
*e++ = (576 - 312 + OPT_SIZE) & 0xff;
e += dhcp_set_ip_options(50, e, RequestedIP);
e += dhcp_set_ip_options(54, e, ServerID);
for (i = 0; i < ARRAY_SIZE(dhcp_params); i++)
e += dhcp_params[i].handle(&dhcp_params[i], e);
*e++ = 55; /* Parameter Request List */
cnt = e++; /* Pointer to count of requested items */
*cnt = 0;
for (i = 0; i < ARRAY_SIZE(dhcp_options); i++) {
if (dhcp_options[i].optional)
continue;
*e++ = dhcp_options[i].option;
*cnt += 1;
}
*e++ = 255; /* End of the list */
/* Pad to minimal length */
while ((e - start) <= DHCP_MIN_EXT_LEN)
*e++ = 0;
return e - start;
}
static struct net_connection *dhcp_con;
static int bootp_request(void)
{
struct bootp *bp;
int ext_len;
int ret;
unsigned char *payload = net_udp_get_payload(dhcp_con);
const char *bfile;
dhcp_state = INIT;
debug("BOOTP broadcast\n");
bp = (struct bootp *)payload;
bp->bp_op = OP_BOOTREQUEST;
bp->bp_htype = HWT_ETHER;
bp->bp_hlen = HWL_ETHER;
bp->bp_hops = 0;
bp->bp_secs = htons(get_time_ns() >> 30);
net_write_ip(&bp->bp_ciaddr, 0);
net_write_ip(&bp->bp_yiaddr, 0);
net_write_ip(&bp->bp_siaddr, 0);
net_write_ip(&bp->bp_giaddr, 0);
memcpy(bp->bp_chaddr, dhcp_con->et->et_src, 6);
bfile = getenv("bootfile");
if (bfile)
safe_strncpy (bp->bp_file, bfile, sizeof(bp->bp_file));
/* Request additional information from the BOOTP/DHCP server */
ext_len = dhcp_extended((u8 *)bp->bp_vend, DHCP_DISCOVER, 0, 0);
Bootp_id = (uint32_t)get_time_ns();
net_copy_uint32(&bp->bp_id, &Bootp_id);
dhcp_state = SELECTING;
ret = net_udp_send(dhcp_con, sizeof(*bp) + ext_len);
return ret;
}
static int dhcp_options_handle(unsigned char option, unsigned char *popt,
int optlen, struct bootp *bp)
{
int i;
struct dhcp_opt *opt;
for (i = 0; i < ARRAY_SIZE(dhcp_options); i++) {
opt = &dhcp_options[i];
if (opt->option == option) {
opt->bp = bp;
opt->handle(opt, popt, optlen);
goto end;
}
}
end:
return i;
}
static void dhcp_options_process(unsigned char *popt, struct bootp *bp)
{
unsigned char *end = popt + sizeof(*bp) + OPT_SIZE;
int oplen;
unsigned char option;
int i;
while (popt < end && *popt != 0xff) {
oplen = *(popt + 1);
option = *popt;
i = dhcp_options_handle(option, popt + 2, oplen, bp);
if (i == ARRAY_SIZE(dhcp_options))
debug("*** Unhandled DHCP Option in OFFER/ACK: %d\n", option);
popt += oplen + 2; /* Process next option */
}
}
static int dhcp_message_type(unsigned char *popt)
{
if (net_read_uint32((uint32_t *)popt) != htonl(BOOTP_VENDOR_MAGIC))
return -1;
popt += 4;
while ( *popt != 0xff ) {
if ( *popt == 53 ) /* DHCP Message Type */
return *(popt + 2);
popt += *(popt + 1) + 2; /* Scan through all options */
}
return -1;
}
static void dhcp_send_request_packet(struct bootp *bp_offer)
{
struct bootp *bp;
int extlen;
IPaddr_t OfferedIP;
unsigned char *payload = net_udp_get_payload(dhcp_con);
debug("%s: Sending DHCPREQUEST\n", __func__);
bp = (struct bootp *)payload;
bp->bp_op = OP_BOOTREQUEST;
bp->bp_htype = HWT_ETHER;
bp->bp_hlen = HWL_ETHER;
bp->bp_hops = 0;
/* FIXME what is this? */
// bp->bp_secs = htons(get_timer(0) / CFG_HZ);
net_copy_ip(&bp->bp_ciaddr, &bp_offer->bp_ciaddr); /* both in network byte order */
net_copy_ip(&bp->bp_yiaddr, &bp_offer->bp_yiaddr);
net_copy_ip(&bp->bp_siaddr, &bp_offer->bp_siaddr);
/*
* RFC3046 requires Relay Agents to discard packets with
* nonzero and offered giaddr
*/
net_write_ip(&bp->bp_giaddr, 0);
memcpy(bp->bp_chaddr, dhcp_con->et->et_src, 6);
/*
* ID is the id of the OFFER packet
*/
net_copy_uint32(&bp->bp_id, &bp_offer->bp_id);
/*
* Copy options from OFFER packet if present
*/
net_copy_ip(&OfferedIP, &bp->bp_yiaddr);
extlen = dhcp_extended((u8 *)bp->bp_vend, DHCP_REQUEST, net_dhcp_server_ip,
OfferedIP);
debug("Transmitting DHCPREQUEST packet\n");
net_udp_send(dhcp_con, sizeof(*bp) + extlen);
}
/*
* Handle DHCP received packets.
*/
static void dhcp_handler(void *ctx, char *packet, unsigned int len)
{
char *pkt = net_eth_to_udp_payload(packet);
struct udphdr *udp = net_eth_to_udphdr(packet);
struct bootp *bp = (struct bootp *)pkt;
len = net_eth_to_udplen(packet);
debug("DHCPHandler: got packet: (len=%d) state: %d\n",
len, dhcp_state);
if (bootp_check_packet(pkt, ntohs(udp->uh_sport), len)) /* Filter out pkts we don't want */
return;
switch (dhcp_state) {
case SELECTING:
/*
* Wait an appropriate time for any potential DHCPOFFER packets
* to arrive. Then select one, and generate DHCPREQUEST response.
* If filename is in format we recognize, assume it is a valid
* OFFER from a server we want.
*/
debug ("%s: state SELECTING, bp_file: \"%s\"\n", __func__, bp->bp_file);
dhcp_state = REQUESTING;
if (net_read_uint32((uint32_t *)&bp->bp_vend[0]) == htonl(BOOTP_VENDOR_MAGIC))
dhcp_options_process((u8 *)&bp->bp_vend[4], bp);
bootp_copy_net_params(bp); /* Store net params from reply */
dhcp_start = get_time_ns();
dhcp_send_request_packet(bp);
break;
case REQUESTING:
debug ("%s: State REQUESTING\n", __func__);
if (dhcp_message_type((u8 *)bp->bp_vend) == DHCP_ACK ) {
if (net_read_uint32((uint32_t *)&bp->bp_vend[0]) == htonl(BOOTP_VENDOR_MAGIC))
dhcp_options_process((u8 *)&bp->bp_vend[4], bp);
bootp_copy_net_params(bp); /* Store net params from reply */
dhcp_state = BOUND;
puts ("DHCP client bound to address ");
print_IPaddr(net_get_ip());
putchar('\n');
return;
}
break;
default:
debug("%s: INVALID STATE\n", __func__);
break;
}
}
static void dhcp_reset_env(void)
{
struct dhcp_opt *opt;
int i;
for (i = 0; i < ARRAY_SIZE(dhcp_options); i++) {
opt = &dhcp_options[i];
if (!opt->barebox_var_name || opt->copy_only_if_valid)
continue;
setenv(opt->barebox_var_name,"");
if (opt->barebox_dhcp_global)
dhcp_set_barebox_global(opt->barebox_dhcp_global,"");
}
}
static void dhcp_global_add(const char *var)
{
char * var_global = asprintf("dhcp.%s", var);
if (!var_global)
return;
globalvar_add_simple(var_global, NULL);
free(var_global);
}
static int dhcp_global_init(void)
{
struct dhcp_opt *opt;
struct dhcp_param *param;
int i;
for (i = 0; i < ARRAY_SIZE(dhcp_options); i++) {
opt = &dhcp_options[i];
if (!opt->barebox_dhcp_global)
continue;
dhcp_global_add(opt->barebox_dhcp_global);
}
for (i = 0; i < ARRAY_SIZE(dhcp_params); i++) {
param = &dhcp_params[i];
if (!param->barebox_dhcp_global)
continue;
dhcp_global_add(param->barebox_dhcp_global);
}
return 0;
}
late_initcall(dhcp_global_init);
static int do_dhcp(int argc, char *argv[])
{
int ret, opt;
int retries = DHCP_DEFAULT_RETRY;
dhcp_reset_env();
getenv_uint("global.dhcp.retries", &retries);
while((opt = getopt(argc, argv, "H:v:c:u:U:r:")) > 0) {
switch(opt) {
case 'H':
dhcp_set_param_data(DHCP_HOSTNAME, optarg);
break;
case 'v':
dhcp_set_param_data(DHCP_VENDOR_ID, optarg);
break;
case 'c':
dhcp_set_param_data(DHCP_CLIENT_ID, optarg);
break;
case 'u':
dhcp_set_param_data(DHCP_CLIENT_UUID, optarg);
break;
case 'U':
dhcp_set_param_data(DHCP_USER_CLASS, optarg);
break;
case 'r':
retries = simple_strtoul(optarg, NULL, 10);
break;
}
}
if (!retries) {
printf("retries is set to zero, set it to %d\n", DHCP_DEFAULT_RETRY);
retries = DHCP_DEFAULT_RETRY;
}
dhcp_con = net_udp_new(0xffffffff, PORT_BOOTPS, dhcp_handler, NULL);
if (IS_ERR(dhcp_con)) {
ret = PTR_ERR(dhcp_con);
goto out;
}
ret = net_udp_bind(dhcp_con, PORT_BOOTPC);
if (ret)
goto out1;
net_set_ip(0);
dhcp_start = get_time_ns();
ret = bootp_request(); /* Basically same as BOOTP */
if (ret)
goto out1;
while (dhcp_state != BOUND) {
if (ctrlc()) {
ret = -EINTR;
goto out1;
}
if (!retries) {
ret = -ETIMEDOUT;
goto out1;
}
net_poll();
if (is_timeout(dhcp_start, 3 * SECOND)) {
dhcp_start = get_time_ns();
printf("T ");
ret = bootp_request();
/* no need to check if retries > 0 as we check if != 0 */
retries--;
if (ret)
goto out1;
}
}
if (dhcp_tftpname[0] != 0) {
IPaddr_t tftpserver = resolv(dhcp_tftpname);
if (tftpserver)
net_set_serverip(tftpserver);
}
out1:
net_unregister(dhcp_con);
out:
if (ret)
printf("dhcp failed: %s\n", strerror(-ret));
return ret;
}
BAREBOX_CMD_HELP_START(dhcp)
BAREBOX_CMD_HELP_TEXT("Options:")
BAREBOX_CMD_HELP_OPT ("-H HOSTNAME", "hostname to send to the DHCP server")
BAREBOX_CMD_HELP_OPT ("-v ID\t", "DHCP Vendor ID (code 60) submitted in DHCP requests")
BAREBOX_CMD_HELP_OPT ("-c ID\t", "DHCP Client ID (code 61) submitted in DHCP requests")
BAREBOX_CMD_HELP_OPT ("-u UUID\t", "DHCP Client UUID (code 97) submitted in DHCP requests")
BAREBOX_CMD_HELP_OPT ("-U CLASS", "DHCP User class (code 77) submitted in DHCP requests")
BAREBOX_CMD_HELP_OPT ("-r RETRY", "retry limit (default 20)");
BAREBOX_CMD_HELP_END
BAREBOX_CMD_START(dhcp)
.cmd = do_dhcp,
BAREBOX_CMD_DESC("DHCP client to obtain IP or boot params")
BAREBOX_CMD_OPTS("[-HvcuUr]")
BAREBOX_CMD_GROUP(CMD_GRP_NET)
BAREBOX_CMD_HELP(cmd_dhcp_help)
BAREBOX_CMD_COMPLETE(empty_complete)
BAREBOX_CMD_END
BAREBOX_MAGICVAR_NAMED(global_dhcp_bootfile, global.dhcp.bootfile, "bootfile returned from DHCP request");
BAREBOX_MAGICVAR_NAMED(global_dhcp_rootpath, global.dhcp.rootpath, "rootpath returned from DHCP request");
BAREBOX_MAGICVAR_NAMED(global_dhcp_vendor_id, global.dhcp.vendor_id, "vendor id to send to the DHCP server");
BAREBOX_MAGICVAR_NAMED(global_dhcp_client_uuid, global.dhcp.client_uuid, "client uuid to send to the DHCP server");
BAREBOX_MAGICVAR_NAMED(global_dhcp_client_id, global.dhcp.client_id, "client id to send to the DHCP server");
BAREBOX_MAGICVAR_NAMED(global_dhcp_user_class, global.dhcp.user_class, "user class to send to the DHCP server");
BAREBOX_MAGICVAR_NAMED(global_dhcp_tftp_server_name, global.dhcp.tftp_server_name, "TFTP server Name returned from DHCP request");
BAREBOX_MAGICVAR_NAMED(global_dhcp_oftree_file, global.dhcp.oftree_file, "OF tree returned from DHCP request (option 224)");
BAREBOX_MAGICVAR_NAMED(global_dhcp_retries, global.dhcp.retries, "retry limit");
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