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hush/networking/udhcp/common.c
Michael McTernan ee0f444f11 udhcp: finish support of classless static routes (now the correct patch!) 
Signed-off-by: Michael McTernan <Michael.McTernan.2001@cs.bris.ac.uk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2011-12-16 17:10:09 +01:00

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/* vi: set sw=4 ts=4: */
/*
* Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#include "common.h"
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
unsigned dhcp_verbose;
#endif
const uint8_t MAC_BCAST_ADDR[6] ALIGN2 = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};
/* Supported options are easily added here.
* See RFC2132 for more options.
* OPTION_REQ: these options are requested by udhcpc (unless -o).
*/
const struct dhcp_optflag dhcp_optflags[] = {
/* flags code */
{ OPTION_IP | OPTION_REQ, 0x01 }, /* DHCP_SUBNET */
{ OPTION_S32 , 0x02 }, /* DHCP_TIME_OFFSET */
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x03 }, /* DHCP_ROUTER */
// { OPTION_IP | OPTION_LIST , 0x04 }, /* DHCP_TIME_SERVER */
// { OPTION_IP | OPTION_LIST , 0x05 }, /* DHCP_NAME_SERVER */
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x06 }, /* DHCP_DNS_SERVER */
// { OPTION_IP | OPTION_LIST , 0x07 }, /* DHCP_LOG_SERVER */
// { OPTION_IP | OPTION_LIST , 0x08 }, /* DHCP_COOKIE_SERVER */
{ OPTION_IP | OPTION_LIST , 0x09 }, /* DHCP_LPR_SERVER */
{ OPTION_STRING_HOST | OPTION_REQ, 0x0c }, /* DHCP_HOST_NAME */
{ OPTION_U16 , 0x0d }, /* DHCP_BOOT_SIZE */
{ OPTION_STRING_HOST | OPTION_REQ, 0x0f }, /* DHCP_DOMAIN_NAME */
{ OPTION_IP , 0x10 }, /* DHCP_SWAP_SERVER */
{ OPTION_STRING , 0x11 }, /* DHCP_ROOT_PATH */
{ OPTION_U8 , 0x17 }, /* DHCP_IP_TTL */
{ OPTION_U16 , 0x1a }, /* DHCP_MTU */
//TODO: why do we request DHCP_BROADCAST? Can't we assume that
//in the unlikely case it is different from typical N.N.255.255,
//server would let us know anyway?
{ OPTION_IP | OPTION_REQ, 0x1c }, /* DHCP_BROADCAST */
{ OPTION_IP_PAIR | OPTION_LIST , 0x21 }, /* DHCP_ROUTES */
{ OPTION_STRING_HOST , 0x28 }, /* DHCP_NIS_DOMAIN */
{ OPTION_IP | OPTION_LIST , 0x29 }, /* DHCP_NIS_SERVER */
{ OPTION_IP | OPTION_LIST | OPTION_REQ, 0x2a }, /* DHCP_NTP_SERVER */
{ OPTION_IP | OPTION_LIST , 0x2c }, /* DHCP_WINS_SERVER */
{ OPTION_U32 , 0x33 }, /* DHCP_LEASE_TIME */
{ OPTION_IP , 0x36 }, /* DHCP_SERVER_ID */
{ OPTION_STRING , 0x38 }, /* DHCP_ERR_MESSAGE */
//TODO: must be combined with 'sname' and 'file' handling:
{ OPTION_STRING_HOST , 0x42 }, /* DHCP_TFTP_SERVER_NAME */
{ OPTION_STRING , 0x43 }, /* DHCP_BOOT_FILE */
//TODO: not a string, but a set of LASCII strings:
// { OPTION_STRING , 0x4D }, /* DHCP_USER_CLASS */
#if ENABLE_FEATURE_UDHCP_RFC3397
{ OPTION_DNS_STRING | OPTION_LIST , 0x77 }, /* DHCP_DOMAIN_SEARCH */
{ OPTION_SIP_SERVERS , 0x78 }, /* DHCP_SIP_SERVERS */
#endif
{ OPTION_STATIC_ROUTES | OPTION_LIST , 0x79 }, /* DHCP_STATIC_ROUTES */
#if ENABLE_FEATURE_UDHCP_8021Q
{ OPTION_U16 , 0x84 }, /* DHCP_VLAN_ID */
{ OPTION_U8 , 0x85 }, /* DHCP_VLAN_PRIORITY */
#endif
{ OPTION_6RD , 0xd4 }, /* DHCP_6RD */
{ OPTION_STATIC_ROUTES | OPTION_LIST , 0xf9 }, /* DHCP_MS_STATIC_ROUTES */
{ OPTION_STRING , 0xfc }, /* DHCP_WPAD */
/* Options below have no match in dhcp_option_strings[],
* are not passed to dhcpc scripts, and cannot be specified
* with "option XXX YYY" syntax in dhcpd config file.
* These entries are only used internally by udhcp[cd]
* to correctly encode options into packets.
*/
{ OPTION_IP , 0x32 }, /* DHCP_REQUESTED_IP */
{ OPTION_U8 , 0x35 }, /* DHCP_MESSAGE_TYPE */
{ OPTION_U16 , 0x39 }, /* DHCP_MAX_SIZE */
//looks like these opts will work just fine even without these defs:
// { OPTION_STRING , 0x3c }, /* DHCP_VENDOR */
// /* not really a string: */
// { OPTION_STRING , 0x3d }, /* DHCP_CLIENT_ID */
{ 0, 0 } /* zeroed terminating entry */
};
/* Used for converting options from incoming packets to env variables
* for udhcpc stript, and for setting options for udhcpd via
* "opt OPTION_NAME OPTION_VALUE" directives in udhcpd.conf file.
*/
/* Must match dhcp_optflags[] order */
const char dhcp_option_strings[] ALIGN1 =
"subnet" "\0" /* DHCP_SUBNET */
"timezone" "\0" /* DHCP_TIME_OFFSET */
"router" "\0" /* DHCP_ROUTER */
// "timesrv" "\0" /* DHCP_TIME_SERVER */
// "namesrv" "\0" /* DHCP_NAME_SERVER */
"dns" "\0" /* DHCP_DNS_SERVER */
// "logsrv" "\0" /* DHCP_LOG_SERVER */
// "cookiesrv" "\0" /* DHCP_COOKIE_SERVER */
"lprsrv" "\0" /* DHCP_LPR_SERVER */
"hostname" "\0" /* DHCP_HOST_NAME */
"bootsize" "\0" /* DHCP_BOOT_SIZE */
"domain" "\0" /* DHCP_DOMAIN_NAME */
"swapsrv" "\0" /* DHCP_SWAP_SERVER */
"rootpath" "\0" /* DHCP_ROOT_PATH */
"ipttl" "\0" /* DHCP_IP_TTL */
"mtu" "\0" /* DHCP_MTU */
"broadcast" "\0" /* DHCP_BROADCAST */
"routes" "\0" /* DHCP_ROUTES */
"nisdomain" "\0" /* DHCP_NIS_DOMAIN */
"nissrv" "\0" /* DHCP_NIS_SERVER */
"ntpsrv" "\0" /* DHCP_NTP_SERVER */
"wins" "\0" /* DHCP_WINS_SERVER */
"lease" "\0" /* DHCP_LEASE_TIME */
"serverid" "\0" /* DHCP_SERVER_ID */
"message" "\0" /* DHCP_ERR_MESSAGE */
"tftp" "\0" /* DHCP_TFTP_SERVER_NAME */
"bootfile" "\0" /* DHCP_BOOT_FILE */
// "userclass" "\0" /* DHCP_USER_CLASS */
#if ENABLE_FEATURE_UDHCP_RFC3397
"search" "\0" /* DHCP_DOMAIN_SEARCH */
// doesn't work in udhcpd.conf since OPTION_SIP_SERVERS
// is not handled yet by "string->option" conversion code:
"sipsrv" "\0" /* DHCP_SIP_SERVERS */
#endif
"staticroutes" "\0"/* DHCP_STATIC_ROUTES */
#if ENABLE_FEATURE_UDHCP_8021Q
"vlanid" "\0" /* DHCP_VLAN_ID */
"vlanpriority" "\0"/* DHCP_VLAN_PRIORITY */
#endif
"ip6rd" "\0" /* DHCP_6RD */
"msstaticroutes""\0"/* DHCP_MS_STATIC_ROUTES */
"wpad" "\0" /* DHCP_WPAD */
;
/* Lengths of the option types in binary form.
* Used by:
* udhcp_str2optset: to determine how many bytes to allocate.
* xmalloc_optname_optval: to estimate string length
* from binary option length: (option[LEN] / dhcp_option_lengths[opt_type])
* is the number of elements, multiply in by one element's string width
* (len_of_option_as_string[opt_type]) and you know how wide string you need.
*/
const uint8_t dhcp_option_lengths[] ALIGN1 = {
[OPTION_IP] = 4,
[OPTION_IP_PAIR] = 8,
// [OPTION_BOOLEAN] = 1,
[OPTION_STRING] = 1, /* ignored by udhcp_str2optset */
[OPTION_STRING_HOST] = 1, /* ignored by udhcp_str2optset */
#if ENABLE_FEATURE_UDHCP_RFC3397
[OPTION_DNS_STRING] = 1, /* ignored by both udhcp_str2optset and xmalloc_optname_optval */
[OPTION_SIP_SERVERS] = 1,
#endif
[OPTION_U8] = 1,
[OPTION_U16] = 2,
// [OPTION_S16] = 2,
[OPTION_U32] = 4,
[OPTION_S32] = 4,
/* Just like OPTION_STRING, we use minimum length here */
[OPTION_STATIC_ROUTES] = 5,
[OPTION_6RD] = 22, /* ignored by udhcp_str2optset */
};
#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
static void log_option(const char *pfx, const uint8_t *opt)
{
if (dhcp_verbose >= 2) {
char buf[256 * 2 + 2];
*bin2hex(buf, (void*) (opt + OPT_DATA), opt[OPT_LEN]) = '\0';
bb_info_msg("%s: 0x%02x %s", pfx, opt[OPT_CODE], buf);
}
}
#else
# define log_option(pfx, opt) ((void)0)
#endif
unsigned FAST_FUNC udhcp_option_idx(const char *name)
{
int n = index_in_strings(dhcp_option_strings, name);
if (n >= 0)
return n;
{
char buf[sizeof(dhcp_option_strings)];
char *d = buf;
const char *s = dhcp_option_strings;
while (s < dhcp_option_strings + sizeof(dhcp_option_strings) - 2) {
*d++ = (*s == '\0' ? ' ' : *s);
s++;
}
*d = '\0';
bb_error_msg_and_die("unknown option '%s', known options: %s", name, buf);
}
}
/* Get an option with bounds checking (warning, result is not aligned) */
uint8_t* FAST_FUNC udhcp_get_option(struct dhcp_packet *packet, int code)
{
uint8_t *optionptr;
int len;
int rem;
int overload = 0;
enum {
FILE_FIELD101 = FILE_FIELD * 0x101,
SNAME_FIELD101 = SNAME_FIELD * 0x101,
};
/* option bytes: [code][len][data1][data2]..[dataLEN] */
optionptr = packet->options;
rem = sizeof(packet->options);
while (1) {
if (rem <= 0) {
bb_error_msg("bad packet, malformed option field");
return NULL;
}
if (optionptr[OPT_CODE] == DHCP_PADDING) {
rem--;
optionptr++;
continue;
}
if (optionptr[OPT_CODE] == DHCP_END) {
if ((overload & FILE_FIELD101) == FILE_FIELD) {
/* can use packet->file, and didn't look at it yet */
overload |= FILE_FIELD101; /* "we looked at it" */
optionptr = packet->file;
rem = sizeof(packet->file);
continue;
}
if ((overload & SNAME_FIELD101) == SNAME_FIELD) {
/* can use packet->sname, and didn't look at it yet */
overload |= SNAME_FIELD101; /* "we looked at it" */
optionptr = packet->sname;
rem = sizeof(packet->sname);
continue;
}
break;
}
len = 2 + optionptr[OPT_LEN];
rem -= len;
if (rem < 0)
continue; /* complain and return NULL */
if (optionptr[OPT_CODE] == code) {
log_option("Option found", optionptr);
return optionptr + OPT_DATA;
}
if (optionptr[OPT_CODE] == DHCP_OPTION_OVERLOAD) {
overload |= optionptr[OPT_DATA];
/* fall through */
}
optionptr += len;
}
/* log3 because udhcpc uses it a lot - very noisy */
log3("Option 0x%02x not found", code);
return NULL;
}
/* Return the position of the 'end' option (no bounds checking) */
int FAST_FUNC udhcp_end_option(uint8_t *optionptr)
{
int i = 0;
while (optionptr[i] != DHCP_END) {
if (optionptr[i] != DHCP_PADDING)
i += optionptr[i + OPT_LEN] + OPT_DATA-1;
i++;
}
return i;
}
/* Add an option (supplied in binary form) to the options.
* Option format: [code][len][data1][data2]..[dataLEN]
*/
void FAST_FUNC udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt)
{
unsigned len;
uint8_t *optionptr = packet->options;
unsigned end = udhcp_end_option(optionptr);
len = OPT_DATA + addopt[OPT_LEN];
/* end position + (option code/length + addopt length) + end option */
if (end + len + 1 >= DHCP_OPTIONS_BUFSIZE) {
//TODO: learn how to use overflow option if we exhaust packet->options[]
bb_error_msg("option 0x%02x did not fit into the packet",
addopt[OPT_CODE]);
return;
}
log_option("Adding option", addopt);
memcpy(optionptr + end, addopt, len);
optionptr[end + len] = DHCP_END;
}
/* Add an one to four byte option to a packet */
void FAST_FUNC udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data)
{
const struct dhcp_optflag *dh;
for (dh = dhcp_optflags; dh->code; dh++) {
if (dh->code == code) {
uint8_t option[6], len;
option[OPT_CODE] = code;
len = dhcp_option_lengths[dh->flags & OPTION_TYPE_MASK];
option[OPT_LEN] = len;
if (BB_BIG_ENDIAN)
data <<= 8 * (4 - len);
/* Assignment is unaligned! */
move_to_unaligned32(&option[OPT_DATA], data);
udhcp_add_binary_option(packet, option);
return;
}
}
bb_error_msg("can't add option 0x%02x", code);
}
/* Find option 'code' in opt_list */
struct option_set* FAST_FUNC udhcp_find_option(struct option_set *opt_list, uint8_t code)
{
while (opt_list && opt_list->data[OPT_CODE] < code)
opt_list = opt_list->next;
if (opt_list && opt_list->data[OPT_CODE] == code)
return opt_list;
return NULL;
}
/* Parse string to IP in network order */
int FAST_FUNC udhcp_str2nip(const char *str, void *arg)
{
len_and_sockaddr *lsa;
lsa = host_and_af2sockaddr(str, 0, AF_INET);
if (!lsa)
return 0;
/* arg maybe unaligned */
move_to_unaligned32((uint32_t*)arg, lsa->u.sin.sin_addr.s_addr);
free(lsa);
return 1;
}
/* udhcp_str2optset:
* Parse string option representation to binary form and add it to opt_list.
* Called to parse "udhcpc -x OPTNAME:OPTVAL"
* and to parse udhcpd.conf's "opt OPTNAME OPTVAL" directives.
*/
/* helper for the helper */
static char *allocate_tempopt_if_needed(
const struct dhcp_optflag *optflag,
char *buffer,
int *length_p)
{
char *allocated = NULL;
if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_BIN) {
const char *end;
allocated = xstrdup(buffer); /* more than enough */
end = hex2bin(allocated, buffer, 255);
if (errno)
bb_error_msg_and_die("malformed hex string '%s'", buffer);
*length_p = end - allocated;
}
return allocated;
}
/* helper: add an option to the opt_list */
static NOINLINE void attach_option(
struct option_set **opt_list,
const struct dhcp_optflag *optflag,
char *buffer,
int length)
{
struct option_set *existing, *new, **curr;
char *allocated = NULL;
existing = udhcp_find_option(*opt_list, optflag->code);
if (!existing) {
log2("Attaching option %02x to list", optflag->code);
allocated = allocate_tempopt_if_needed(optflag, buffer, &length);
#if ENABLE_FEATURE_UDHCP_RFC3397
if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
/* reuse buffer and length for RFC1035-formatted string */
allocated = buffer = (char *)dname_enc(NULL, 0, buffer, &length);
}
#endif
/* make a new option */
new = xmalloc(sizeof(*new));
new->data = xmalloc(length + OPT_DATA);
new->data[OPT_CODE] = optflag->code;
new->data[OPT_LEN] = length;
memcpy(new->data + OPT_DATA, (allocated ? allocated : buffer), length);
curr = opt_list;
while (*curr && (*curr)->data[OPT_CODE] < optflag->code)
curr = &(*curr)->next;
new->next = *curr;
*curr = new;
goto ret;
}
if (optflag->flags & OPTION_LIST) {
unsigned old_len;
/* add it to an existing option */
log2("Attaching option %02x to existing member of list", optflag->code);
allocated = allocate_tempopt_if_needed(optflag, buffer, &length);
old_len = existing->data[OPT_LEN];
#if ENABLE_FEATURE_UDHCP_RFC3397
if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_DNS_STRING) {
/* reuse buffer and length for RFC1035-formatted string */
allocated = buffer = (char *)dname_enc(existing->data + OPT_DATA, old_len, buffer, &length);
}
#endif
if (old_len + length < 255) {
/* actually 255 is ok too, but adding a space can overlow it */
existing->data = xrealloc(existing->data, OPT_DATA + 1 + old_len + length);
if ((optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING
|| (optflag->flags & OPTION_TYPE_MASK) == OPTION_STRING_HOST
) {
/* add space separator between STRING options in a list */
existing->data[OPT_DATA + old_len] = ' ';
old_len++;
}
memcpy(existing->data + OPT_DATA + old_len, buffer, length);
existing->data[OPT_LEN] = old_len + length;
} /* else, ignore the data, we could put this in a second option in the future */
} /* else, ignore the new data */
ret:
free(allocated);
}
int FAST_FUNC udhcp_str2optset(const char *const_str, void *arg)
{
struct option_set **opt_list = arg;
char *opt, *val;
char *str;
const struct dhcp_optflag *optflag;
struct dhcp_optflag bin_optflag;
unsigned optcode;
int retval, length;
/* IP_PAIR needs 8 bytes, STATIC_ROUTES needs 9 max */
char buffer[9] ALIGNED(4);
uint16_t *result_u16 = (uint16_t *) buffer;
uint32_t *result_u32 = (uint32_t *) buffer;
/* Cheat, the only *const* str possible is "" */
str = (char *) const_str;
opt = strtok(str, " \t=");
if (!opt)
return 0;
optcode = bb_strtou(opt, NULL, 0);
if (!errno && optcode < 255) {
/* Raw (numeric) option code */
bin_optflag.flags = OPTION_BIN;
bin_optflag.code = optcode;
optflag = &bin_optflag;
} else {
optflag = &dhcp_optflags[udhcp_option_idx(opt)];
}
retval = 0;
do {
val = strtok(NULL, ", \t");
if (!val)
break;
length = dhcp_option_lengths[optflag->flags & OPTION_TYPE_MASK];
retval = 0;
opt = buffer; /* new meaning for variable opt */
switch (optflag->flags & OPTION_TYPE_MASK) {
case OPTION_IP:
retval = udhcp_str2nip(val, buffer);
break;
case OPTION_IP_PAIR:
retval = udhcp_str2nip(val, buffer);
val = strtok(NULL, ", \t/-");
if (!val)
retval = 0;
if (retval)
retval = udhcp_str2nip(val, buffer + 4);
break;
case OPTION_STRING:
case OPTION_STRING_HOST:
#if ENABLE_FEATURE_UDHCP_RFC3397
case OPTION_DNS_STRING:
#endif
length = strnlen(val, 254);
if (length > 0) {
opt = val;
retval = 1;
}
break;
// case OPTION_BOOLEAN: {
// static const char no_yes[] ALIGN1 = "no\0yes\0";
// buffer[0] = retval = index_in_strings(no_yes, val);
// retval++; /* 0 - bad; 1: "no" 2: "yes" */
// break;
// }
case OPTION_U8:
buffer[0] = bb_strtou32(val, NULL, 0);
retval = (errno == 0);
break;
/* htonX are macros in older libc's, using temp var
* in code below for safety */
/* TODO: use bb_strtoX? */
case OPTION_U16: {
uint32_t tmp = bb_strtou32(val, NULL, 0);
*result_u16 = htons(tmp);
retval = (errno == 0 /*&& tmp < 0x10000*/);
break;
}
// case OPTION_S16: {
// long tmp = bb_strtoi32(val, NULL, 0);
// *result_u16 = htons(tmp);
// retval = (errno == 0);
// break;
// }
case OPTION_U32: {
uint32_t tmp = bb_strtou32(val, NULL, 0);
*result_u32 = htonl(tmp);
retval = (errno == 0);
break;
}
case OPTION_S32: {
int32_t tmp = bb_strtoi32(val, NULL, 0);
*result_u32 = htonl(tmp);
retval = (errno == 0);
break;
}
case OPTION_STATIC_ROUTES: {
/* Input: "a.b.c.d/m" */
/* Output: mask(1 byte),pfx(0-4 bytes),gw(4 bytes) */
unsigned mask;
char *slash = strchr(val, '/');
if (slash) {
*slash = '\0';
retval = udhcp_str2nip(val, buffer + 1);
buffer[0] = mask = bb_strtou(slash + 1, NULL, 10);
val = strtok(NULL, ", \t/-");
if (!val || mask > 32 || errno)
retval = 0;
if (retval) {
length = ((mask + 7) >> 3) + 5;
retval = udhcp_str2nip(val, buffer + (length - 4));
}
}
break;
}
case OPTION_BIN: /* handled in attach_option() */
opt = val;
retval = 1;
default:
break;
}
if (retval)
attach_option(opt_list, optflag, opt, length);
} while (retval && (optflag->flags & OPTION_LIST));
return retval;
}
/* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
int FAST_FUNC sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip)
{
char hexstrbuf[16 * 2];
bin2hex(hexstrbuf, (void*)ip, 16);
return sprintf(dest, /* "%s" */
"%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s:%.4s",
/* pre, */
hexstrbuf + 0 * 4,
hexstrbuf + 1 * 4,
hexstrbuf + 2 * 4,
hexstrbuf + 3 * 4,
hexstrbuf + 4 * 4,
hexstrbuf + 5 * 4,
hexstrbuf + 6 * 4,
hexstrbuf + 7 * 4
);
}
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