wireless: update radiotap parser

Upstream radiotap has adopted the namespace
proposal David Young made and I then took care
of, for which I had adapted the radiotap parser
as a library outside the kernel. This brings
the in-kernel parser up to speed.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 271 insertions, 130 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index a3f0a7ed31ac..5b3569b2a74c 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1561,37 +1561,82 @@ ieee80211_get_response_rate(struct ieee80211_supported_band *sband,
  * Documentation in Documentation/networking/radiotap-headers.txt
  */
 
+struct radiotap_align_size {
+        uint8_t align:4, size:4;
+};
+
+struct ieee80211_radiotap_namespace {
+        const struct radiotap_align_size *align_size;
+        int n_bits;
+        uint32_t oui;
+        uint8_t subns;
+};
+
+struct ieee80211_radiotap_vendor_namespaces {
+        const struct ieee80211_radiotap_namespace *ns;
+        int n_ns;
+};
+
 /**
  * struct ieee80211_radiotap_iterator - tracks walk thru present radiotap args
- * @rtheader: pointer to the radiotap header we are walking through
- * @max_length: length of radiotap header in cpu byte ordering
- * @this_arg_index: IEEE80211_RADIOTAP_... index of current arg
- * @this_arg: pointer to current radiotap arg
- * @arg_index: internal next argument index
- * @arg: internal next argument pointer
- * @next_bitmap: internal pointer to next present u32
- * @bitmap_shifter: internal shifter for curr u32 bitmap, b0 set == arg present
+ * @this_arg_index: index of current arg, valid after each successful call
+ *      to ieee80211_radiotap_iterator_next()
+ * @this_arg: pointer to current radiotap arg; it is valid after each
+ *      call to ieee80211_radiotap_iterator_next() but also after
+ *      ieee80211_radiotap_iterator_init() where it will point to
+ *      the beginning of the actual data portion
+ * @this_arg_size: length of the current arg, for convenience
+ * @current_namespace: pointer to the current namespace definition
+ *      (or internally %NULL if the current namespace is unknown)
+ * @is_radiotap_ns: indicates whether the current namespace is the default
+ *      radiotap namespace or not
+ *
+ * @overrides: override standard radiotap fields
+ * @n_overrides: number of overrides
+ *
+ * @_rtheader: pointer to the radiotap header we are walking through
+ * @_max_length: length of radiotap header in cpu byte ordering
+ * @_arg_index: next argument index
+ * @_arg: next argument pointer
+ * @_next_bitmap: internal pointer to next present u32
+ * @_bitmap_shifter: internal shifter for curr u32 bitmap, b0 set == arg present
+ * @_vns: vendor namespace definitions
+ * @_next_ns_data: beginning of the next namespace's data
+ * @_reset_on_ext: internal; reset the arg index to 0 when going to the
+ *      next bitmap word
+ *
+ * Describes the radiotap parser state. Fields prefixed with an underscore
+ * must not be used by users of the parser, only by the parser internally.
  */
 
 struct ieee80211_radiotap_iterator {
-        struct ieee80211_radiotap_header *rtheader;
-        int max_length;
+        struct ieee80211_radiotap_header *_rtheader;
+        const struct ieee80211_radiotap_vendor_namespaces *_vns;
+        const struct ieee80211_radiotap_namespace *current_namespace;
+
+        unsigned char *_arg, *_next_ns_data;
+        uint32_t *_next_bitmap;
+
+        unsigned char *this_arg;
         int this_arg_index;
-        u8 *this_arg;
+        int this_arg_size;
 
-        int arg_index;
-        u8 *arg;
-        __le32 *next_bitmap;
-        u32 bitmap_shifter;
+        int is_radiotap_ns;
+
+        int _max_length;
+        int _arg_index;
+        uint32_t _bitmap_shifter;
+        int _reset_on_ext;
 };
 
 extern int ieee80211_radiotap_iterator_init(
-   struct ieee80211_radiotap_iterator *iterator,
-   struct ieee80211_radiotap_header *radiotap_header,
-   int max_length);
+        struct ieee80211_radiotap_iterator *iterator,
+        struct ieee80211_radiotap_header *radiotap_header,
+        int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns);
 
 extern int ieee80211_radiotap_iterator_next(
-   struct ieee80211_radiotap_iterator *iterator);
+        struct ieee80211_radiotap_iterator *iterator);
+
 
 extern const unsigned char rfc1042_header[6];
 extern const unsigned char bridge_tunnel_header[6];
diff --git a/include/net/ieee80211_radiotap.h b/include/net/ieee80211_radiotap.h
index 9d3d86aaccbb..af49f8ab7f81 100644
--- a/include/net/ieee80211_radiotap.h
+++ b/include/net/ieee80211_radiotap.h
@@ -198,6 +198,10 @@ enum ieee80211_radiotap_type {
         IEEE80211_RADIOTAP_TX_FLAGS = 15,
         IEEE80211_RADIOTAP_RTS_RETRIES = 16,
         IEEE80211_RADIOTAP_DATA_RETRIES = 17,
+
+        /* valid in every it_present bitmap, even vendor namespaces */
+        IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE = 29,
+        IEEE80211_RADIOTAP_VENDOR_NAMESPACE = 30,
         IEEE80211_RADIOTAP_EXT = 31
 };
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 85e382aa894e..e392820a4c33 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1010,7 +1010,8 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
                 (struct ieee80211_radiotap_header *) skb->data;
         struct ieee80211_supported_band *sband;
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-        int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len);
+        int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len,
+                                                   NULL);
 
         sband = tx->local->hw.wiphy->bands[tx->channel->band];
 
@@ -1046,7 +1047,7 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
                                  * because it will be recomputed and added
                                  * on transmission
                                  */
-                                if (skb->len < (iterator.max_length + FCS_LEN))
+                                if (skb->len < (iterator._max_length + FCS_LEN))
                                         return false;
 
                                 skb_trim(skb, skb->len - FCS_LEN);
@@ -1073,10 +1074,10 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
 
         /*
          * remove the radiotap header
-         * iterator->max_length was sanity-checked against
+         * iterator->_max_length was sanity-checked against
          * skb->len by iterator init
          */
-        skb_pull(skb, iterator.max_length);
+        skb_pull(skb, iterator._max_length);
 
         return true;
 }
diff --git a/net/wireless/radiotap.c b/net/wireless/radiotap.c
index f591871a7b4f..1332c445d1c7 100644
--- a/net/wireless/radiotap.c
+++ b/net/wireless/radiotap.c
@@ -2,6 +2,16 @@
  * Radiotap parser
  *
  * Copyright 2007               Andy Green <andy@warmcat.com>
+ * Copyright 2009               Johannes Berg <johannes@sipsolutions.net>
+ *
+ * This program 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.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See COPYING for more details.
  */
 
 #include <net/cfg80211.h>
@@ -10,6 +20,35 @@
 
 /* function prototypes and related defs are in include/net/cfg80211.h */
 
+static const struct radiotap_align_size rtap_namespace_sizes[] = {
+        [IEEE80211_RADIOTAP_TSFT] = { .align = 8, .size = 8, },
+        [IEEE80211_RADIOTAP_FLAGS] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_RATE] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_CHANNEL] = { .align = 2, .size = 4, },
+        [IEEE80211_RADIOTAP_FHSS] = { .align = 2, .size = 2, },
+        [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_DBM_ANTNOISE] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_LOCK_QUALITY] = { .align = 2, .size = 2, },
+        [IEEE80211_RADIOTAP_TX_ATTENUATION] = { .align = 2, .size = 2, },
+        [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = { .align = 2, .size = 2, },
+        [IEEE80211_RADIOTAP_DBM_TX_POWER] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_ANTENNA] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_DB_ANTNOISE] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_RX_FLAGS] = { .align = 2, .size = 2, },
+        [IEEE80211_RADIOTAP_TX_FLAGS] = { .align = 2, .size = 2, },
+        [IEEE80211_RADIOTAP_RTS_RETRIES] = { .align = 1, .size = 1, },
+        [IEEE80211_RADIOTAP_DATA_RETRIES] = { .align = 1, .size = 1, },
+        /*
+         * add more here as they are defined in radiotap.h
+         */
+};
+
+static const struct ieee80211_radiotap_namespace radiotap_ns = {
+        .n_bits = sizeof(rtap_namespace_sizes) / sizeof(rtap_namespace_sizes[0]),
+        .align_size = rtap_namespace_sizes,
+};
+
 /**
  * ieee80211_radiotap_iterator_init - radiotap parser iterator initialization
  * @iterator: radiotap_iterator to initialize
@@ -50,9 +89,9 @@
  */
 
 int ieee80211_radiotap_iterator_init(
-    struct ieee80211_radiotap_iterator *iterator,
-    struct ieee80211_radiotap_header *radiotap_header,
-    int max_length)
+        struct ieee80211_radiotap_iterator *iterator,
+        struct ieee80211_radiotap_header *radiotap_header,
+        int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns)
 {
         /* Linux only supports version 0 radiotap format */
         if (radiotap_header->it_version)
@@ -62,19 +101,24 @@ int ieee80211_radiotap_iterator_init(
         if (max_length < get_unaligned_le16(&radiotap_header->it_len))
                 return -EINVAL;
 
-        iterator->rtheader = radiotap_header;
-        iterator->max_length = get_unaligned_le16(&radiotap_header->it_len);
-        iterator->arg_index = 0;
-        iterator->bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
-        iterator->arg = (u8 *)radiotap_header + sizeof(*radiotap_header);
-        iterator->this_arg = NULL;
+        iterator->_rtheader = radiotap_header;
+        iterator->_max_length = get_unaligned_le16(&radiotap_header->it_len);
+        iterator->_arg_index = 0;
+        iterator->_bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
+        iterator->_arg = (uint8_t *)radiotap_header + sizeof(*radiotap_header);
+        iterator->_reset_on_ext = 0;
+        iterator->_next_bitmap = &radiotap_header->it_present;
+        iterator->_next_bitmap++;
+        iterator->_vns = vns;
+        iterator->current_namespace = &radiotap_ns;
+        iterator->is_radiotap_ns = 1;
 
         /* find payload start allowing for extended bitmap(s) */
 
-        if (unlikely(iterator->bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT))) {
-                while (get_unaligned_le32(iterator->arg) &
-                       (1 << IEEE80211_RADIOTAP_EXT)) {
-                        iterator->arg += sizeof(u32);
+        if (iterator->_bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT)) {
+                while (get_unaligned_le32(iterator->_arg) &
+                                        (1 << IEEE80211_RADIOTAP_EXT)) {
+                        iterator->_arg += sizeof(uint32_t);
 
                         /*
                          * check for insanity where the present bitmaps
@@ -82,12 +126,13 @@ int ieee80211_radiotap_iterator_init(
                          * stated radiotap header length
                          */
 
-                        if (((ulong)iterator->arg -
-                             (ulong)iterator->rtheader) > iterator->max_length)
+                        if ((unsigned long)iterator->_arg -
+                            (unsigned long)iterator->_rtheader >
+                            (unsigned long)iterator->_max_length)
                                 return -EINVAL;
                 }
 
-                iterator->arg += sizeof(u32);
+                iterator->_arg += sizeof(uint32_t);
 
                 /*
                  * no need to check again for blowing past stated radiotap
@@ -96,12 +141,36 @@ int ieee80211_radiotap_iterator_init(
                  */
         }
 
+        iterator->this_arg = iterator->_arg;
+
         /* we are all initialized happily */
 
         return 0;
 }
 EXPORT_SYMBOL(ieee80211_radiotap_iterator_init);
 
+static void find_ns(struct ieee80211_radiotap_iterator *iterator,
+                    uint32_t oui, uint8_t subns)
+{
+        int i;
+
+        iterator->current_namespace = NULL;
+
+        if (!iterator->_vns)
+                return;
+
+        for (i = 0; i < iterator->_vns->n_ns; i++) {
+                if (iterator->_vns->ns[i].oui != oui)
+                        continue;
+                if (iterator->_vns->ns[i].subns != subns)
+                        continue;
+
+                iterator->current_namespace = &iterator->_vns->ns[i];
+                break;
+        }
+}
+
+
 
 /**
  * ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg
@@ -127,99 +196,80 @@ EXPORT_SYMBOL(ieee80211_radiotap_iterator_init);
  */
 
 int ieee80211_radiotap_iterator_next(
-    struct ieee80211_radiotap_iterator *iterator)
+        struct ieee80211_radiotap_iterator *iterator)
 {
-
-        /*
-         * small length lookup table for all radiotap types we heard of
-         * starting from b0 in the bitmap, so we can walk the payload
-         * area of the radiotap header
-         *
-         * There is a requirement to pad args, so that args
-         * of a given length must begin at a boundary of that length
-         * -- but note that compound args are allowed (eg, 2 x u16
-         * for IEEE80211_RADIOTAP_CHANNEL) so total arg length is not
-         * a reliable indicator of alignment requirement.
-         *
-         * upper nybble: content alignment for arg
-         * lower nybble: content length for arg
-         */
-
-        static const u8 rt_sizes[] = {
-                [IEEE80211_RADIOTAP_TSFT] = 0x88,
-                [IEEE80211_RADIOTAP_FLAGS] = 0x11,
-                [IEEE80211_RADIOTAP_RATE] = 0x11,
-                [IEEE80211_RADIOTAP_CHANNEL] = 0x24,
-                [IEEE80211_RADIOTAP_FHSS] = 0x22,
-                [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = 0x11,
-                [IEEE80211_RADIOTAP_DBM_ANTNOISE] = 0x11,
-                [IEEE80211_RADIOTAP_LOCK_QUALITY] = 0x22,
-                [IEEE80211_RADIOTAP_TX_ATTENUATION] = 0x22,
-                [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = 0x22,
-                [IEEE80211_RADIOTAP_DBM_TX_POWER] = 0x11,
-                [IEEE80211_RADIOTAP_ANTENNA] = 0x11,
-                [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = 0x11,
-                [IEEE80211_RADIOTAP_DB_ANTNOISE] = 0x11,
-                [IEEE80211_RADIOTAP_RX_FLAGS] = 0x22,
-                [IEEE80211_RADIOTAP_TX_FLAGS] = 0x22,
-                [IEEE80211_RADIOTAP_RTS_RETRIES] = 0x11,
-                [IEEE80211_RADIOTAP_DATA_RETRIES] = 0x11,
-                /*
-                 * add more here as they are defined in
-                 * include/net/ieee80211_radiotap.h
-                 */
-        };
-
-        /*
-         * for every radiotap entry we can at
-         * least skip (by knowing the length)...
-         */
-
-        while (iterator->arg_index < sizeof(rt_sizes)) {
+        while (1) {
                 int hit = 0;
-                int pad;
+                int pad, align, size, subns, vnslen;
+                uint32_t oui;
 
-                if (!(iterator->bitmap_shifter & 1))
+                /* if no more EXT bits, that's it */
+                if ((iterator->_arg_index % 32) == IEEE80211_RADIOTAP_EXT &&
+                    !(iterator->_bitmap_shifter & 1))
+                        return -ENOENT;
+
+                if (!(iterator->_bitmap_shifter & 1))
                         goto next_entry; /* arg not present */
 
+                /* get alignment/size of data */
+                switch (iterator->_arg_index % 32) {
+                case IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE:
+                case IEEE80211_RADIOTAP_EXT:
+                        align = 1;
+                        size = 0;
+                        break;
+                case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
+                        align = 2;
+                        size = 6;
+                        break;
+                default:
+                        if (!iterator->current_namespace ||
+                            iterator->_arg_index >= iterator->current_namespace->n_bits) {
+                                if (iterator->current_namespace == &radiotap_ns)
+                                        return -ENOENT;
+                                align = 0;
+                        } else {
+                                align = iterator->current_namespace->align_size[iterator->_arg_index].align;
+                                size = iterator->current_namespace->align_size[iterator->_arg_index].size;
+                        }
+                        if (!align) {
+                                /* skip all subsequent data */
+                                iterator->_arg = iterator->_next_ns_data;
+                                /* give up on this namespace */
+                                iterator->current_namespace = NULL;
+                                goto next_entry;
+                        }
+                        break;
+                }
+
                 /*
                  * arg is present, account for alignment padding
-                 *  8-bit args can be at any alignment
-                 * 16-bit args must start on 16-bit boundary
-                 * 32-bit args must start on 32-bit boundary
-                 * 64-bit args must start on 64-bit boundary
                  *
-                 * note that total arg size can differ from alignment of
-                 * elements inside arg, so we use upper nybble of length
-                 * table to base alignment on
-                 *
-                 * also note: these alignments are ** relative to the
-                 * start of the radiotap header **.  There is no guarantee
+                 * Note that these alignments are relative to the start
+                 * of the radiotap header.  There is no guarantee
                  * that the radiotap header itself is aligned on any
                  * kind of boundary.
                  *
-                 * the above is why get_unaligned() is used to dereference
-                 * multibyte elements from the radiotap area
+                 * The above is why get_unaligned() is used to dereference
+                 * multibyte elements from the radiotap area.
                  */
 
-                pad = (((ulong)iterator->arg) -
-                        ((ulong)iterator->rtheader)) &
-                        ((rt_sizes[iterator->arg_index] >> 4) - 1);
+                pad = ((unsigned long)iterator->_arg -
+                       (unsigned long)iterator->_rtheader) & (align - 1);
 
                 if (pad)
-                        iterator->arg +=
-                                (rt_sizes[iterator->arg_index] >> 4) - pad;
+                        iterator->_arg += align - pad;
 
                 /*
                  * this is what we will return to user, but we need to
                  * move on first so next call has something fresh to test
                  */
-                iterator->this_arg_index = iterator->arg_index;
-                iterator->this_arg = iterator->arg;
-                hit = 1;
+                iterator->this_arg_index = iterator->_arg_index;
+                iterator->this_arg = iterator->_arg;
+                iterator->this_arg_size = size;
 
                 /* internally move on the size of this arg */
-                iterator->arg += rt_sizes[iterator->arg_index] & 0x0f;
+                iterator->_arg += size;
 
                 /*
                  * check for insanity where we are given a bitmap that
@@ -228,32 +278,73 @@ int ieee80211_radiotap_iterator_next(
                  * max_length on the last arg, never exceeding it.
                  */
 
-                if (((ulong)iterator->arg - (ulong)iterator->rtheader) >
-                    iterator->max_length)
+                if ((unsigned long)iterator->_arg -
+                    (unsigned long)iterator->_rtheader >
+                    (unsigned long)iterator->_max_length)
                         return -EINVAL;
 
-        next_entry:
-                iterator->arg_index++;
-                if (unlikely((iterator->arg_index & 31) == 0)) {
-                        /* completed current u32 bitmap */
-                        if (iterator->bitmap_shifter & 1) {
-                                /* b31 was set, there is more */
-                                /* move to next u32 bitmap */
-                                iterator->bitmap_shifter =
-                                    get_unaligned_le32(iterator->next_bitmap);
-                                iterator->next_bitmap++;
-                        } else
-                                /* no more bitmaps: end */
-                                iterator->arg_index = sizeof(rt_sizes);
-                } else /* just try the next bit */
-                        iterator->bitmap_shifter >>= 1;
+                /* these special ones are valid in each bitmap word */
+                switch (iterator->_arg_index % 32) {
+                case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
+                        iterator->_bitmap_shifter >>= 1;
+                        iterator->_arg_index++;
+
+                        iterator->_reset_on_ext = 1;
+
+                        vnslen = get_unaligned_le16(iterator->this_arg + 4);
+                        iterator->_next_ns_data = iterator->_arg + vnslen;
+                        oui = (*iterator->this_arg << 16) |
+                                (*(iterator->this_arg + 1) << 8) |
+                                *(iterator->this_arg + 2);
+                        subns = *(iterator->this_arg + 3);
+
+                        find_ns(iterator, oui, subns);
+
+                        iterator->is_radiotap_ns = 0;
+                        /* allow parsers to show this information */
+                        iterator->this_arg_index =
+                                IEEE80211_RADIOTAP_VENDOR_NAMESPACE;
+                        iterator->this_arg_size += vnslen;
+                        if ((unsigned long)iterator->this_arg +
+                            iterator->this_arg_size -
+                            (unsigned long)iterator->_rtheader >
+                            (unsigned long)(unsigned long)iterator->_max_length)
+                                return -EINVAL;
+                        hit = 1;
+                        break;
+                case IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE:
+                        iterator->_bitmap_shifter >>= 1;
+                        iterator->_arg_index++;
+
+                        iterator->_reset_on_ext = 1;
+                        iterator->current_namespace = &radiotap_ns;
+                        iterator->is_radiotap_ns = 1;
+                        break;
+                case IEEE80211_RADIOTAP_EXT:
+                        /*
+                         * bit 31 was set, there is more
+                         * -- move to next u32 bitmap
+                         */
+                        iterator->_bitmap_shifter =
+                                get_unaligned_le32(iterator->_next_bitmap);
+                        iterator->_next_bitmap++;
+                        if (iterator->_reset_on_ext)
+                                iterator->_arg_index = 0;
+                        else
+                                iterator->_arg_index++;
+                        iterator->_reset_on_ext = 0;
+                        break;
+                default:
+                        /* we've got a hit! */
+                        hit = 1;
+ next_entry:
+                        iterator->_bitmap_shifter >>= 1;
+                        iterator->_arg_index++;
+                }
 
                 /* if we found a valid arg earlier, return it now */
                 if (hit)
                         return 0;
         }
-
-        /* we don't know how to handle any more args, we're done */
-        return -ENOENT;
 }
 EXPORT_SYMBOL(ieee80211_radiotap_iterator_next);