/* * packet-radiotap.c * Decode packets with a Radiotap header * * $Id: packet-radiotap.c,v 1.3 2004/02/01 04:29:07 jmayer Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * Copied from README.developer * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program 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 this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include "packet-ieee80211.h" #include "packet-radiotap.h" struct ieee80211_radiotap_header { guint8 it_version; /* Version 0. Only increases * for drastic changes, * introduction of compatible * new fields does not count. */ guint8 it_pad; guint16 it_len; /* length of the whole * header in bytes, including * it_version, it_pad, * it_len, and data fields. */ guint32 it_present; /* A bitmap telling which * fields are present. Set bit 31 * (0x80000000) to extend the * bitmap by another 32 bits. * Additional extensions are made * by setting bit 31. */ }; enum ieee80211_radiotap_type { IEEE80211_RADIOTAP_TSFT = 0, IEEE80211_RADIOTAP_FLAGS = 1, IEEE80211_RADIOTAP_RATE = 2, IEEE80211_RADIOTAP_CHANNEL = 3, IEEE80211_RADIOTAP_FHSS = 4, IEEE80211_RADIOTAP_DBM_ANTSIGNAL = 5, IEEE80211_RADIOTAP_DBM_ANTNOISE = 6, IEEE80211_RADIOTAP_LOCK_QUALITY = 7, IEEE80211_RADIOTAP_TX_ATTENUATION = 8, IEEE80211_RADIOTAP_DB_TX_ATTENUATION = 9, IEEE80211_RADIOTAP_DBM_TX_POWER = 10, IEEE80211_RADIOTAP_ANTENNA = 11, IEEE80211_RADIOTAP_DB_ANTSIGNAL = 12, IEEE80211_RADIOTAP_DB_ANTNOISE = 13, IEEE80211_RADIOTAP_EXT = 31 }; /* Channel flags. */ #define IEEE80211_CHAN_TURBO 0x0010 /* Turbo channel */ #define IEEE80211_CHAN_CCK 0x0020 /* CCK channel */ #define IEEE80211_CHAN_OFDM 0x0040 /* OFDM channel */ #define IEEE80211_CHAN_2GHZ 0x0080 /* 2 GHz spectrum channel. */ #define IEEE80211_CHAN_5GHZ 0x0100 /* 5 GHz spectrum channel */ #define IEEE80211_CHAN_PASSIVE 0x0200 /* Only passive scan allowed */ #define IEEE80211_CHAN_DYN 0x0400 /* Dynamic CCK-OFDM channel */ #define IEEE80211_CHAN_GFSK 0x0800 /* GFSK channel (FHSS PHY) */ /* * Useful combinations of channel characteristics. */ #define IEEE80211_CHAN_FHSS \ (IEEE80211_CHAN_2GHZ | IEEE80211_CHAN_GFSK) #define IEEE80211_CHAN_A \ (IEEE80211_CHAN_5GHZ | IEEE80211_CHAN_OFDM) #define IEEE80211_CHAN_B \ (IEEE80211_CHAN_2GHZ | IEEE80211_CHAN_CCK) #define IEEE80211_CHAN_PUREG \ (IEEE80211_CHAN_2GHZ | IEEE80211_CHAN_OFDM) #define IEEE80211_CHAN_G \ (IEEE80211_CHAN_2GHZ | IEEE80211_CHAN_DYN) #define IEEE80211_CHAN_T \ (IEEE80211_CHAN_5GHZ | IEEE80211_CHAN_OFDM | IEEE80211_CHAN_TURBO) #define IEEE80211_CHAN_108G \ (IEEE80211_CHAN_G | IEEE80211_CHAN_TURBO) #define IEEE80211_CHAN_108PUREG \ (IEEE80211_CHAN_PUREG | IEEE80211_CHAN_TURBO) /* For IEEE80211_RADIOTAP_FLAGS */ #define IEEE80211_RADIOTAP_F_CFP 0x01 /* sent/received * during CFP */ #define IEEE80211_RADIOTAP_F_SHORTPRE 0x02 /* sent/received * with short * preamble */ #define IEEE80211_RADIOTAP_F_WEP 0x04 /* sent/received * with WEP encryption */ #define IEEE80211_RADIOTAP_F_FRAG 0x08 /* sent/received * with fragmentation */ /* protocol */ static int proto_radiotap = -1; static int hf_radiotap_version = -1; static int hf_radiotap_length = -1; static int hf_radiotap_mactime = -1; static int hf_radiotap_channel_frequency = -1; static int hf_radiotap_channel_flags = -1; static int hf_radiotap_datarate = -1; static int hf_radiotap_antenna = -1; static int hf_radiotap_antsignal = -1; static int hf_radiotap_antnoise = -1; static int hf_radiotap_txpower = -1; static int hf_radiotap_preamble = -1; static gint ett_radiotap = -1; static dissector_handle_t ieee80211_handle; static void dissect_radiotap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree); void capture_radiotap(const guchar *pd, int offset, int len, packet_counts *ld) { const struct ieee80211_radiotap_header *hdr; if(!BYTES_ARE_IN_FRAME(offset, len, (int)sizeof(*hdr))) { ld->other ++; return; } hdr = (const struct ieee80211_radiotap_header *)pd; if(!BYTES_ARE_IN_FRAME(offset, len, hdr->it_len)) { ld->other ++; return; } /* 802.11 header follows */ capture_ieee80211(pd, offset + hdr->it_len, len, ld); } void proto_register_radiotap(void) { static const value_string phy_type[] = { { 0, "Unknown" }, { IEEE80211_CHAN_A, "802.11a" }, { IEEE80211_CHAN_B, "802.11b" }, { IEEE80211_CHAN_PUREG, "802.11g (pure-g)" }, { IEEE80211_CHAN_G, "802.11g" }, { IEEE80211_CHAN_T, "802.11a (turbo)" }, { IEEE80211_CHAN_108PUREG, "802.11g (pure-g, turbo)" }, { IEEE80211_CHAN_108G, "802.11g (turbo)" }, { IEEE80211_CHAN_FHSS, "FHSS" }, { 0, NULL }, }; static const value_string preamble_type[] = { { 0, "Long" }, { 1, "Short" }, { 0, NULL }, }; static hf_register_info hf[] = { { &hf_radiotap_version, { "Header revision", "radiotap.version", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_length, { "Header length", "radiotap.length", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_preamble, { "Preamble", "radiotap.flags.preamble", FT_UINT32, BASE_DEC, VALS(preamble_type), 0x0, "", HFILL } }, { &hf_radiotap_mactime, { "MAC timestamp", "radiotap.mactime", FT_UINT64, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_channel_frequency, { "Channel frequency", "radiotap.channel.freq", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_channel_flags, { "Channel type", "radiotap.channel.flags", FT_UINT32, BASE_HEX, VALS(phy_type), 0x0, "", HFILL } }, { &hf_radiotap_datarate, { "Data rate", "radiotap.datarate", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_antenna, { "Antenna", "radiotap.antenna", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_antsignal, { "SSI Signal", "radiotap.antsignal", FT_INT32, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_antnoise, { "SSI Noise", "radiotap.antnoise", FT_INT32, BASE_DEC, NULL, 0x0, "", HFILL } }, { &hf_radiotap_txpower, { "Transmit power", "radiotap.txpower", FT_INT32, BASE_DEC, NULL, 0x0, "", HFILL } }, }; static gint *ett[] = { &ett_radiotap }; proto_radiotap = proto_register_protocol("IEEE 802.11 Radiotap Capture header", "802.11 Radiotap", "radiotap"); proto_register_field_array(proto_radiotap, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); register_dissector("radiotap", dissect_radiotap, proto_radiotap); } /* * Convert MHz frequency to IEEE channel number. */ static int ieee80211_mhz2ieee(int freq, int flags) { if (flags & IEEE80211_CHAN_2GHZ) { /* 2GHz band */ if (freq == 2484) return 14; if (freq < 2484) return (freq - 2407) / 5; else return 15 + ((freq - 2512) / 20); } else if (flags & IEEE80211_CHAN_5GHZ) { /* 5Ghz band */ return (freq - 5000) / 5; } else { /* either, guess */ if (freq == 2484) return 14; if (freq < 2484) return (freq - 2407) / 5; if (freq < 5000) return 15 + ((freq - 2512) / 20); return (freq - 5000) / 5; } } static void dissect_radiotap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { #define BITNO_32(x) (((x) >> 16) ? 16 + BITNO_16((x) >> 16) : BITNO_16((x))) #define BITNO_16(x) (((x) >> 8) ? 8 + BITNO_8((x) >> 8) : BITNO_8((x))) #define BITNO_8(x) (((x) >> 4) ? 4 + BITNO_4((x) >> 4) : BITNO_4((x))) #define BITNO_4(x) (((x) >> 2) ? 2 + BITNO_2((x) >> 2) : BITNO_2((x))) #define BITNO_2(x) (((x) & 2) ? 1 : 0) #define BIT(n) (1 << n) proto_tree *radiotap_tree; proto_item *ti; int offset; guint32 version; guint32 length; guint32 rate, freq, flags; guint32 present, next_present; int bit; if(check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "WLAN"); if(check_col(pinfo->cinfo, COL_INFO)) col_clear(pinfo->cinfo, COL_INFO); offset = 0; version = tvb_get_guint8(tvb, offset); length = tvb_get_letohs(tvb, offset+2); present = tvb_get_letohl(tvb, offset+4); offset+=sizeof(struct ieee80211_radiotap_header); if(check_col(pinfo->cinfo, COL_INFO)) col_add_fstr(pinfo->cinfo, COL_INFO, "Radiotap Capture v%x, Length %d", version, length); /* Dissect the packet */ if (tree) { ti = proto_tree_add_protocol_format(tree, proto_radiotap, tvb, 0, length, "Radiotap Header"); radiotap_tree = proto_item_add_subtree(ti, ett_radiotap); for (; present; present = next_present) { /* clear the least significant bit that is set */ next_present = present & (present - 1); /* extract the least significant bit that is set */ bit = BITNO_32(present ^ next_present); switch (bit) { case IEEE80211_RADIOTAP_FLAGS: proto_tree_add_uint(radiotap_tree, hf_radiotap_preamble, tvb, 0, 0, (tvb_get_guint8(tvb, offset) & IEEE80211_RADIOTAP_F_SHORTPRE) != 0); offset++; /* XXX CFP, WEP, FRAG */ #if 0 capability = tvb_get_letohs (tvb, offset); cap_item = proto_tree_add_uint_format (tree, ff_capture, tvb, offset, 2, capability, "Capability Information: 0x%04X", capability); cap_tree = proto_item_add_subtree (cap_item, ett_cap_tree); proto_tree_add_boolean (cap_tree, ff_cf_ess, tvb, offset, 2, capability); proto_tree_add_boolean (cap_tree, ff_cf_ibss, tvb, offset, 2, capability); if (ESS_SET (capability) != 0) /* This is an AP */ proto_tree_add_uint (cap_tree, ff_cf_ap_poll, tvb, offset, 2, capability); else /* This is a STA */ proto_tree_add_uint (cap_tree, ff_cf_sta_poll, tvb, offset, 2, capability); proto_tree_add_boolean (cap_tree, ff_cf_privacy, tvb, offset, 2, capability); proto_tree_add_boolean (cap_tree, ff_cf_preamble, tvb, offset, 2, capability); proto_tree_add_boolean (cap_tree, ff_cf_pbcc, tvb, offset, 2, capability); proto_tree_add_boolean (cap_tree, ff_cf_agility, tvb, offset, 2, capability); proto_tree_add_boolean (cap_tree, ff_short_slot_time, tvb, offset, 2, capability); proto_tree_add_boolean (cap_tree, ff_dsss_ofdm, tvb, offset, 2, capability); #endif break; case IEEE80211_RADIOTAP_RATE: rate = tvb_get_guint8(tvb, offset) & 0x7f; proto_tree_add_uint_format(radiotap_tree, hf_radiotap_datarate, tvb, offset, 1, tvb_get_guint8(tvb, offset), "Datarate: %d.%d Mbps", rate / 2, rate & 1 ? 5 : 0); offset++; break; case IEEE80211_RADIOTAP_DBM_ANTSIGNAL: case IEEE80211_RADIOTAP_DB_ANTSIGNAL: /* XXX distinguish units */ proto_tree_add_int(radiotap_tree, hf_radiotap_antsignal, tvb, offset, 1, tvb_get_guint8(tvb, offset)); offset++; break; case IEEE80211_RADIOTAP_DBM_ANTNOISE: case IEEE80211_RADIOTAP_DB_ANTNOISE: /* XXX distinguish units */ proto_tree_add_int(radiotap_tree, hf_radiotap_antnoise, tvb, offset, 1, tvb_get_guint8(tvb, offset)); offset++; break; case IEEE80211_RADIOTAP_ANTENNA: proto_tree_add_uint(radiotap_tree, hf_radiotap_antenna, tvb, offset, 1, tvb_get_guint8(tvb, offset)); offset++; break; case IEEE80211_RADIOTAP_DBM_TX_POWER: proto_tree_add_int(radiotap_tree, hf_radiotap_txpower, tvb, offset, 1, tvb_get_guint8(tvb, offset)); offset++; break; case IEEE80211_RADIOTAP_CHANNEL: freq = tvb_get_letohs(tvb, offset); flags = tvb_get_letohs(tvb, offset+2); proto_tree_add_uint_format(radiotap_tree, hf_radiotap_channel_frequency, tvb, offset, 2, freq, "Channel: %u (chan %u)", freq, ieee80211_mhz2ieee(freq, flags)); proto_tree_add_uint(radiotap_tree, hf_radiotap_channel_flags, tvb, offset+2, 2, flags); offset+=4; break; case IEEE80211_RADIOTAP_FHSS: case IEEE80211_RADIOTAP_LOCK_QUALITY: case IEEE80211_RADIOTAP_TX_ATTENUATION: case IEEE80211_RADIOTAP_DB_TX_ATTENUATION: #if 0 tvb_get_letohs(tvb, offset); #endif offset+=2; break; case IEEE80211_RADIOTAP_TSFT: proto_tree_add_item(radiotap_tree, hf_radiotap_mactime, tvb, offset, 8, FALSE); offset+=8; break; default: /* * This indicates a field whose size we do not * know, so we cannot proceed. */ next_present = 0; continue; } } } /* dissect the 802.11 header next */ call_dissector(ieee80211_handle, tvb_new_subset(tvb, length, -1, -1), pinfo, tree); #undef BITNO_32 #undef BITNO_16 #undef BITNO_8 #undef BITNO_4 #undef BITNO_2 #undef BIT } void proto_reg_handoff_radiotap(void) { dissector_handle_t radiotap_handle; /* handle for 802.11 dissector */ ieee80211_handle = find_dissector("wlan"); radiotap_handle = create_dissector_handle(dissect_radiotap, proto_radiotap); dissector_add("wtap_encap", WTAP_ENCAP_IEEE_802_11_WLAN_BSD, radiotap_handle); }