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openwrt/package/network/utils/iwinfo/src/iwinfo_wext_scan.c

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/*
* iwinfo - Wireless Information Library - Linux Wireless Extension Backend
*
* Copyright (C) 2009-2010 Jo-Philipp Wich <xm@subsignal.org>
*
* The iwinfo library is free software: you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* The iwinfo library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with the iwinfo library. If not, see http://www.gnu.org/licenses/.
*
* Parts of this code are derived from the Linux wireless tools, iwlib.c,
* iwlist.c and iwconfig.c in particular.
*/
#include "iwinfo.h"
#include "iwinfo_wext.h"
static int wext_ioctl(const char *ifname, int cmd, struct iwreq *wrq)
{
strncpy(wrq->ifr_name, ifname, IFNAMSIZ);
return iwinfo_ioctl(cmd, wrq);
}
static inline double wext_freq2float(const struct iw_freq *in)
{
int i;
double res = (double) in->m;
for(i = 0; i < in->e; i++) res *= 10;
return res;
}
static inline int wext_extract_event(struct stream_descr *stream, struct iw_event *iwe, int wev)
{
const struct iw_ioctl_description *descr = NULL;
int event_type = 0;
unsigned int event_len = 1;
char *pointer;
unsigned cmd_index; /* *MUST* be unsigned */
/* Check for end of stream */
if((stream->current + IW_EV_LCP_PK_LEN) > stream->end)
return 0;
/* Extract the event header (to get the event id).
* Note : the event may be unaligned, therefore copy... */
memcpy((char *) iwe, stream->current, IW_EV_LCP_PK_LEN);
/* Check invalid events */
if(iwe->len <= IW_EV_LCP_PK_LEN)
return -1;
/* Get the type and length of that event */
if(iwe->cmd <= SIOCIWLAST)
{
cmd_index = iwe->cmd - SIOCIWFIRST;
if(cmd_index < standard_ioctl_num)
descr = &(standard_ioctl_descr[cmd_index]);
}
else
{
cmd_index = iwe->cmd - IWEVFIRST;
if(cmd_index < standard_event_num)
descr = &(standard_event_descr[cmd_index]);
}
if(descr != NULL)
event_type = descr->header_type;
/* Unknown events -> event_type=0 => IW_EV_LCP_PK_LEN */
event_len = event_type_size[event_type];
/* Fixup for earlier version of WE */
if((wev <= 18) && (event_type == IW_HEADER_TYPE_POINT))
event_len += IW_EV_POINT_OFF;
/* Check if we know about this event */
if(event_len <= IW_EV_LCP_PK_LEN)
{
/* Skip to next event */
stream->current += iwe->len;
return 2;
}
event_len -= IW_EV_LCP_PK_LEN;
/* Set pointer on data */
if(stream->value != NULL)
pointer = stream->value; /* Next value in event */
else
pointer = stream->current + IW_EV_LCP_PK_LEN; /* First value in event */
/* Copy the rest of the event (at least, fixed part) */
if((pointer + event_len) > stream->end)
{
/* Go to next event */
stream->current += iwe->len;
return -2;
}
/* Fixup for WE-19 and later : pointer no longer in the stream */
/* Beware of alignement. Dest has local alignement, not packed */
if( (wev > 18) && (event_type == IW_HEADER_TYPE_POINT) )
memcpy((char *) iwe + IW_EV_LCP_LEN + IW_EV_POINT_OFF, pointer, event_len);
else
memcpy((char *) iwe + IW_EV_LCP_LEN, pointer, event_len);
/* Skip event in the stream */
pointer += event_len;
/* Special processing for iw_point events */
if(event_type == IW_HEADER_TYPE_POINT)
{
/* Check the length of the payload */
unsigned int extra_len = iwe->len - (event_len + IW_EV_LCP_PK_LEN);
if(extra_len > 0)
{
/* Set pointer on variable part (warning : non aligned) */
iwe->u.data.pointer = pointer;
/* Check that we have a descriptor for the command */
if(descr == NULL)
/* Can't check payload -> unsafe... */
iwe->u.data.pointer = NULL; /* Discard paylod */
else
{
/* Those checks are actually pretty hard to trigger,
* because of the checks done in the kernel... */
unsigned int token_len = iwe->u.data.length * descr->token_size;
/* Ugly fixup for alignement issues.
* If the kernel is 64 bits and userspace 32 bits,
* we have an extra 4+4 bytes.
* Fixing that in the kernel would break 64 bits userspace. */
if((token_len != extra_len) && (extra_len >= 4))
{
uint16_t alt_dlen = *((uint16_t *) pointer);
unsigned int alt_token_len = alt_dlen * descr->token_size;
if((alt_token_len + 8) == extra_len)
{
/* Ok, let's redo everything */
pointer -= event_len;
pointer += 4;
/* Dest has local alignement, not packed */
memcpy((char *) iwe + IW_EV_LCP_LEN + IW_EV_POINT_OFF, pointer, event_len);
pointer += event_len + 4;
iwe->u.data.pointer = pointer;
token_len = alt_token_len;
}
}
/* Discard bogus events which advertise more tokens than
* what they carry... */
if(token_len > extra_len)
iwe->u.data.pointer = NULL; /* Discard paylod */
/* Check that the advertised token size is not going to
* produce buffer overflow to our caller... */
if((iwe->u.data.length > descr->max_tokens)
&& !(descr->flags & IW_DESCR_FLAG_NOMAX))
iwe->u.data.pointer = NULL; /* Discard paylod */
/* Same for underflows... */
if(iwe->u.data.length < descr->min_tokens)
iwe->u.data.pointer = NULL; /* Discard paylod */
}
}
else
/* No data */
iwe->u.data.pointer = NULL;
/* Go to next event */
stream->current += iwe->len;
}
else
{
/* Ugly fixup for alignement issues.
* If the kernel is 64 bits and userspace 32 bits,
* we have an extra 4 bytes.
* Fixing that in the kernel would break 64 bits userspace. */
if((stream->value == NULL)
&& ((((iwe->len - IW_EV_LCP_PK_LEN) % event_len) == 4)
|| ((iwe->len == 12) && ((event_type == IW_HEADER_TYPE_UINT) ||
(event_type == IW_HEADER_TYPE_QUAL))) ))
{
pointer -= event_len;
pointer += 4;
/* Beware of alignement. Dest has local alignement, not packed */
memcpy((char *) iwe + IW_EV_LCP_LEN, pointer, event_len);
pointer += event_len;
}
/* Is there more value in the event ? */
if((pointer + event_len) <= (stream->current + iwe->len))
/* Go to next value */
stream->value = pointer;
else
{
/* Go to next event */
stream->value = NULL;
stream->current += iwe->len;
}
}
return 1;
}
static inline void wext_fill_wpa(unsigned char *iebuf, int ielen, struct iwinfo_scanlist_entry *e)
{
static unsigned char ms_oui[3] = { 0x00, 0x50, 0xf2 };
while (ielen >= 2 && ielen >= iebuf[1])
{
switch (iebuf[0])
{
case 48: /* RSN */
iwinfo_parse_rsn(&e->crypto, iebuf + 2, iebuf[1],
IWINFO_CIPHER_CCMP, IWINFO_KMGMT_8021x);
break;
case 221: /* Vendor */
if (iebuf[1] >= 4 && !memcmp(iebuf + 2, ms_oui, 3) && iebuf[5] == 1)
iwinfo_parse_rsn(&e->crypto, iebuf + 6, iebuf[1] - 4,
IWINFO_CIPHER_TKIP, IWINFO_KMGMT_PSK);
break;
}
ielen -= iebuf[1] + 2;
iebuf += iebuf[1] + 2;
}
}
static inline void wext_fill_entry(struct stream_descr *stream, struct iw_event *event,
struct iw_range *iw_range, int has_range, struct iwinfo_scanlist_entry *e)
{
int i;
double freq;
/* Now, let's decode the event */
switch(event->cmd)
{
case SIOCGIWAP:
memcpy(e->mac, &event->u.ap_addr.sa_data, 6);
break;
case SIOCGIWFREQ:
if( event->u.freq.m >= 1000 )
{
freq = wext_freq2float(&(event->u.freq));
for(i = 0; i < iw_range->num_frequency; i++)
{
if( wext_freq2float(&iw_range->freq[i]) == freq )
{
e->channel = iw_range->freq[i].i;
break;
}
}
}
else
{
e->channel = event->u.freq.m;
}
break;
case SIOCGIWMODE:
switch(event->u.mode)
{
case 1:
e->mode = IWINFO_OPMODE_ADHOC;
break;
case 2:
case 3:
e->mode = IWINFO_OPMODE_MASTER;
break;
default:
e->mode = IWINFO_OPMODE_UNKNOWN;
break;
}
break;
case SIOCGIWESSID:
if( event->u.essid.pointer && event->u.essid.length && event->u.essid.flags )
memcpy(e->ssid, event->u.essid.pointer, event->u.essid.length);
break;
case SIOCGIWENCODE:
e->crypto.enabled = !(event->u.data.flags & IW_ENCODE_DISABLED);
break;
case IWEVQUAL:
e->signal = event->u.qual.level;
e->quality = event->u.qual.qual;
e->quality_max = iw_range->max_qual.qual;
break;
#if 0
case SIOCGIWRATE:
if(state->val_index == 0)
{
lua_pushstring(L, "bitrates");
lua_newtable(L);
}
//iw_print_bitrate(buffer, sizeof(buffer), event->u.bitrate.value);
snprintf(buffer, sizeof(buffer), "%d", event->u.bitrate.value);
lua_pushinteger(L, state->val_index + 1);
lua_pushstring(L, buffer);
lua_settable(L, -3);
/* Check for termination */
if(stream->value == NULL)
{
lua_settable(L, -3);
state->val_index = 0;
} else
state->val_index++;
break;
#endif
case IWEVGENIE:
wext_fill_wpa(event->u.data.pointer, event->u.data.length, e);
break;
}
}
int wext_get_scanlist(const char *ifname, char *buf, int *len)
{
struct iwreq wrq;
struct iw_scan_req scanopt; /* Options for 'set' */
unsigned char *buffer = NULL; /* Results */
int buflen = IW_SCAN_MAX_DATA; /* Min for compat WE<17 */
struct iw_range range;
int has_range = 1;
struct timeval tv; /* Select timeout */
int timeout = 15000000; /* 15s */
int entrylen = 0;
struct iwinfo_scanlist_entry e;
wrq.u.data.pointer = (caddr_t) &range;
wrq.u.data.length = sizeof(struct iw_range);
wrq.u.data.flags = 0;
if( wext_ioctl(ifname, SIOCGIWRANGE, &wrq) >= 0 )
{
/* Init timeout value -> 250ms between set and first get */
tv.tv_sec = 0;
tv.tv_usec = 250000;
/* Clean up set args */
memset(&scanopt, 0, sizeof(scanopt));
wrq.u.data.pointer = NULL;
wrq.u.data.flags = 0;
wrq.u.data.length = 0;
/* Initiate Scanning */
if( wext_ioctl(ifname, SIOCSIWSCAN, &wrq) >= 0 )
{
timeout -= tv.tv_usec;
/* Forever */
while(1)
{
fd_set rfds; /* File descriptors for select */
int last_fd; /* Last fd */
int ret;
/* Guess what ? We must re-generate rfds each time */
FD_ZERO(&rfds);
last_fd = -1;
/* In here, add the rtnetlink fd in the list */
/* Wait until something happens */
ret = select(last_fd + 1, &rfds, NULL, NULL, &tv);
/* Check if there was an error */
if(ret < 0)
{
if(errno == EAGAIN || errno == EINTR)
continue;
return -1;
}
/* Check if there was a timeout */
if(ret == 0)
{
unsigned char *newbuf;
realloc:
/* (Re)allocate the buffer - realloc(NULL, len) == malloc(len) */
newbuf = realloc(buffer, buflen);
if(newbuf == NULL)
{
if(buffer)
free(buffer);
return -1;
}
buffer = newbuf;
/* Try to read the results */
wrq.u.data.pointer = buffer;
wrq.u.data.flags = 0;
wrq.u.data.length = buflen;
if( wext_ioctl(ifname, SIOCGIWSCAN, &wrq) )
{
/* Check if buffer was too small (WE-17 only) */
if((errno == E2BIG) && (range.we_version_compiled > 16))
{
/* Some driver may return very large scan results, either
* because there are many cells, or because they have many
* large elements in cells (like IWEVCUSTOM). Most will
* only need the regular sized buffer. We now use a dynamic
* allocation of the buffer to satisfy everybody. Of course,
* as we don't know in advance the size of the array, we try
* various increasing sizes. Jean II */
/* Check if the driver gave us any hints. */
if(wrq.u.data.length > buflen)
buflen = wrq.u.data.length;
else
buflen *= 2;
/* Try again */
goto realloc;
}
/* Check if results not available yet */
if(errno == EAGAIN)
{
/* Restart timer for only 100ms*/
tv.tv_sec = 0;
tv.tv_usec = 100000;
timeout -= tv.tv_usec;
if(timeout > 0)
continue; /* Try again later */
}
/* Bad error */
free(buffer);
return -1;
} else {
/* We have the results, go to process them */
break;
}
}
}
if( wrq.u.data.length )
{
struct iw_event iwe;
struct stream_descr stream;
int ret;
int first = 1;
memset(&stream, 0, sizeof(stream));
stream.current = (char *)buffer;
stream.end = (char *)buffer + wrq.u.data.length;
do
{
/* Extract an event and print it */
ret = wext_extract_event(&stream, &iwe, range.we_version_compiled);
if(ret >= 0)
{
if( (iwe.cmd == SIOCGIWAP) || (ret == 0) )
{
if( first )
{
first = 0;
}
else if( (entrylen + sizeof(struct iwinfo_scanlist_entry)) <= IWINFO_BUFSIZE )
{
/* if encryption is off, clear the crypto strunct */
if( !e.crypto.enabled )
memset(&e.crypto, 0, sizeof(struct iwinfo_crypto_entry));
memcpy(&buf[entrylen], &e, sizeof(struct iwinfo_scanlist_entry));
entrylen += sizeof(struct iwinfo_scanlist_entry);
}
else
{
/* we exceed the callers buffer size, abort here ... */
break;
}
memset(&e, 0, sizeof(struct iwinfo_scanlist_entry));
}
wext_fill_entry(&stream, &iwe, &range, has_range, &e);
}
} while(ret > 0);
free(buffer);
*len = entrylen;
return 0;
}
*len = 0;
free(buffer);
return 0;
}
}
return -1;
}
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