Use 64-bit TX/RX byte counters for statistics

If the driver supports 64-bit TX/RX byte counters, use them directly.
The old 32-bit counter extension is maintained for backwards
compatibility with older drivers.

For nl80211 driver interface, the newer NL80211_STA_INFO_RX_BYTES64 and
NL80211_STA_INFO_TX_BYTES64 attributes are used when available. This
resolves the race vulnerable 32-bit value wrap/overflow. Rework RADIUS
accounting to use these for Acct-Input-Octets, Acct-Input-Gigawords,
Acct-Output-Octets, and Acct-Output-Gigawords, these values are often
used for billing purposes.

Signed-off-by: Nick Lowe <nick.lowe@lugatech.com>

diff --git a/src/ap/accounting.c b/src/ap/accounting.c
index 86f6cee..9357a46 100644 (file)
--- a/src/ap/accounting.c
+++ b/src/ap/accounting.c
@@ -167,19 +167,25 @@ static int accounting_sta_update_stats(struct hostapd_data *hapd,
        if (hostapd_drv_read_sta_data(hapd, data, sta->addr))
                return -1;
 
-       if (sta->last_rx_bytes > data->rx_bytes)
-               sta->acct_input_gigawords++;
-       if (sta->last_tx_bytes > data->tx_bytes)
-               sta->acct_output_gigawords++;
-       sta->last_rx_bytes = data->rx_bytes;
-       sta->last_tx_bytes = data->tx_bytes;
+       if (!data->bytes_64bit) {
+               /* Extend 32-bit counters from the driver to 64-bit counters */
+               if (sta->last_rx_bytes_lo > data->rx_bytes)
+                       sta->last_rx_bytes_hi++;
+               sta->last_rx_bytes_lo = data->rx_bytes;
+
+               if (sta->last_tx_bytes_lo > data->tx_bytes)
+                       sta->last_tx_bytes_hi++;
+               sta->last_tx_bytes_lo = data->tx_bytes;
+       }
 
        hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_RADIUS,
-                      HOSTAPD_LEVEL_DEBUG, "updated TX/RX stats: "
-                      "Acct-Input-Octets=%lu Acct-Input-Gigawords=%u "
-                      "Acct-Output-Octets=%lu Acct-Output-Gigawords=%u",
-                      sta->last_rx_bytes, sta->acct_input_gigawords,
-                      sta->last_tx_bytes, sta->acct_output_gigawords);
+                      HOSTAPD_LEVEL_DEBUG,
+                      "updated TX/RX stats: rx_bytes=%llu [%u:%u] tx_bytes=%llu [%u:%u] bytes_64bit=%d",
+                      data->rx_bytes, sta->last_rx_bytes_hi,
+                      sta->last_rx_bytes_lo,
+                      data->tx_bytes, sta->last_tx_bytes_hi,
+                      sta->last_tx_bytes_lo,
+                      data->bytes_64bit);
 
        return 0;
 }
@@ -224,8 +230,10 @@ void accounting_sta_start(struct hostapd_data *hapd, struct sta_info *sta)
                       (unsigned long long) sta->acct_session_id);
 
        os_get_reltime(&sta->acct_session_start);
-       sta->last_rx_bytes = sta->last_tx_bytes = 0;
-       sta->acct_input_gigawords = sta->acct_output_gigawords = 0;
+       sta->last_rx_bytes_hi = 0;
+       sta->last_rx_bytes_lo = 0;
+       sta->last_tx_bytes_hi = 0;
+       sta->last_tx_bytes_lo = 0;
        hostapd_drv_sta_clear_stats(hapd, sta->addr);
 
        if (!hapd->conf->radius->acct_server)
@@ -254,7 +262,7 @@ static void accounting_sta_report(struct hostapd_data *hapd,
        int cause = sta->acct_terminate_cause;
        struct hostap_sta_driver_data data;
        struct os_reltime now_r, diff;
-       u32 gigawords;
+       u64 bytes;
 
        if (!hapd->conf->radius->acct_server)
                return;
@@ -288,37 +296,37 @@ static void accounting_sta_report(struct hostapd_data *hapd,
                        wpa_printf(MSG_INFO, "Could not add Acct-Output-Packets");
                        goto fail;
                }
+               if (data.bytes_64bit)
+                       bytes = data.rx_bytes;
+               else
+                       bytes = ((u64) sta->last_rx_bytes_hi << 32) |
+                               sta->last_rx_bytes_lo;
                if (!radius_msg_add_attr_int32(msg,
                                               RADIUS_ATTR_ACCT_INPUT_OCTETS,
-                                              data.rx_bytes)) {
+                                              (u32) bytes)) {
                        wpa_printf(MSG_INFO, "Could not add Acct-Input-Octets");
                        goto fail;
                }
-               gigawords = sta->acct_input_gigawords;
-#if __WORDSIZE == 64
-               gigawords += data.rx_bytes >> 32;
-#endif
-               if (gigawords &&
-                   !radius_msg_add_attr_int32(
-                           msg, RADIUS_ATTR_ACCT_INPUT_GIGAWORDS,
-                           gigawords)) {
+               if (!radius_msg_add_attr_int32(msg,
+                                              RADIUS_ATTR_ACCT_INPUT_GIGAWORDS,
+                                              (u32) (bytes >> 32))) {
                        wpa_printf(MSG_INFO, "Could not add Acct-Input-Gigawords");
                        goto fail;
                }
+               if (data.bytes_64bit)
+                       bytes = data.tx_bytes;
+               else
+                       bytes = ((u64) sta->last_tx_bytes_hi << 32) |
+                               sta->last_tx_bytes_lo;
                if (!radius_msg_add_attr_int32(msg,
                                               RADIUS_ATTR_ACCT_OUTPUT_OCTETS,
-                                              data.tx_bytes)) {
+                                              (u32) bytes)) {
                        wpa_printf(MSG_INFO, "Could not add Acct-Output-Octets");
                        goto fail;
                }
-               gigawords = sta->acct_output_gigawords;
-#if __WORDSIZE == 64
-               gigawords += data.tx_bytes >> 32;
-#endif
-               if (gigawords &&
-                   !radius_msg_add_attr_int32(
-                           msg, RADIUS_ATTR_ACCT_OUTPUT_GIGAWORDS,
-                           gigawords)) {
+               if (!radius_msg_add_attr_int32(msg,
+                                              RADIUS_ATTR_ACCT_OUTPUT_GIGAWORDS,
+                                              (u32) (bytes >> 32))) {
                        wpa_printf(MSG_INFO, "Could not add Acct-Output-Gigawords");
                        goto fail;
                }

diff --git a/src/ap/ctrl_iface_ap.c b/src/ap/ctrl_iface_ap.c
index c98978f..4f93ac2 100644 (file)
--- a/src/ap/ctrl_iface_ap.c
+++ b/src/ap/ctrl_iface_ap.c
@@ -35,7 +35,7 @@ static int hostapd_get_sta_tx_rx(struct hostapd_data *hapd,
                return 0;
 
        ret = os_snprintf(buf, buflen, "rx_packets=%lu\ntx_packets=%lu\n"
-                         "rx_bytes=%lu\ntx_bytes=%lu\n",
+                         "rx_bytes=%llu\ntx_bytes=%llu\n",
                          data.rx_packets, data.tx_packets,
                          data.rx_bytes, data.tx_bytes);
        if (os_snprintf_error(buflen, ret))

diff --git a/src/ap/sta_info.h b/src/ap/sta_info.h
index 94976d7..d36302f 100644 (file)
--- a/src/ap/sta_info.h
+++ b/src/ap/sta_info.h
@@ -109,10 +109,11 @@ struct sta_info {
        int acct_terminate_cause; /* Acct-Terminate-Cause */
        int acct_interim_interval; /* Acct-Interim-Interval */
 
-       unsigned long last_rx_bytes;
-       unsigned long last_tx_bytes;
-       u32 acct_input_gigawords; /* Acct-Input-Gigawords */
-       u32 acct_output_gigawords; /* Acct-Output-Gigawords */
+       /* For extending 32-bit driver counters to 64-bit counters */
+       u32 last_rx_bytes_hi;
+       u32 last_rx_bytes_lo;
+       u32 last_tx_bytes_hi;
+       u32 last_tx_bytes_lo;
 
        u8 *challenge; /* IEEE 802.11 Shared Key Authentication Challenge */
 

diff --git a/src/drivers/driver.h b/src/drivers/driver.h
index 3e9e0a7..2315226 100644 (file)
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -1373,7 +1373,9 @@ struct wpa_driver_capa {
 struct hostapd_data;
 
 struct hostap_sta_driver_data {
-       unsigned long rx_packets, tx_packets, rx_bytes, tx_bytes;
+       unsigned long rx_packets, tx_packets;
+       unsigned long long rx_bytes, tx_bytes;
+       int bytes_64bit; /* whether 64-bit byte counters are supported */
        unsigned long current_tx_rate;
        unsigned long inactive_msec;
        unsigned long flags;

diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
index d09be88..5fec430 100644 (file)
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -5381,6 +5381,8 @@ static int get_sta_handler(struct nl_msg *msg, void *arg)
                [NL80211_STA_INFO_RX_PACKETS] = { .type = NLA_U32 },
                [NL80211_STA_INFO_TX_PACKETS] = { .type = NLA_U32 },
                [NL80211_STA_INFO_TX_FAILED] = { .type = NLA_U32 },
+               [NL80211_STA_INFO_RX_BYTES64] = { .type = NLA_U64 },
+               [NL80211_STA_INFO_TX_BYTES64] = { .type = NLA_U64 },
        };
 
        nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
@@ -5406,10 +5408,23 @@ static int get_sta_handler(struct nl_msg *msg, void *arg)
        if (stats[NL80211_STA_INFO_INACTIVE_TIME])
                data->inactive_msec =
                        nla_get_u32(stats[NL80211_STA_INFO_INACTIVE_TIME]);
+       /* For backwards compatibility, fetch the 32-bit counters first. */
        if (stats[NL80211_STA_INFO_RX_BYTES])
                data->rx_bytes = nla_get_u32(stats[NL80211_STA_INFO_RX_BYTES]);
        if (stats[NL80211_STA_INFO_TX_BYTES])
                data->tx_bytes = nla_get_u32(stats[NL80211_STA_INFO_TX_BYTES]);
+       if (stats[NL80211_STA_INFO_RX_BYTES64] &&
+           stats[NL80211_STA_INFO_TX_BYTES64]) {
+               /*
+                * The driver supports 64-bit counters, so use them to override
+                * the 32-bit values.
+                */
+               data->rx_bytes =
+                       nla_get_u64(stats[NL80211_STA_INFO_RX_BYTES64]);
+               data->tx_bytes =
+                       nla_get_u64(stats[NL80211_STA_INFO_TX_BYTES64]);
+               data->bytes_64bit = 1;
+       }
        if (stats[NL80211_STA_INFO_RX_PACKETS])
                data->rx_packets =
                        nla_get_u32(stats[NL80211_STA_INFO_RX_PACKETS]);