> Date: Wed, 3 Feb 2016 13:27:50 +0100
> From: Stefan Sperling <s...@stsp.name>
>
> Currently, tcpdump displays 802.11 control frames as "type#4" and
> doesn't give more information than that.
>
> This diff makes tcpdump show the subtype of such frames, and pretty-print
> a few subtypes in verbose mode. There are more subtypes but these can
> be pretty-printed later.
>
> This can be tested with:
>
> ifconfig iwn0 mediaopt monitor up
> tcpdump -n -i iwn0 -y IEEE802_11_RADIO -v -s 1500 type ctl
>
> Whether such frames can be seen depends on the driver's RX filter
> settings in monitor mode. Another driver I've tested with is zyd(4).
>
> ok?
ok kettenis@
> Index: print-802_11.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/tcpdump/print-802_11.c,v
> retrieving revision 1.29
> diff -u -p -r1.29 print-802_11.c
> --- print-802_11.c 1 Feb 2016 10:09:44 -0000 1.29
> +++ print-802_11.c 3 Feb 2016 12:21:20 -0000
> @@ -37,6 +37,25 @@
> #include "addrtoname.h"
> #include "interface.h"
>
> +const char *ieee80211_ctl_subtype_name[] = {
> + "reserved#0",
> + "reserved#1",
> + "reserved#2",
> + "reserved#3",
> + "reserved#4",
> + "reserved#5",
> + "reserved#6",
> + "wrapper",
> + "block ack request",
> + "block ack",
> + "ps poll",
> + "rts",
> + "cts",
> + "ack",
> + "cf-end",
> + "cf-end-ack",
> +};
> +
> const char *ieee80211_mgt_subtype_name[] = {
> "association request",
> "association response",
> @@ -813,6 +832,69 @@ ieee80211_frame(struct ieee80211_frame *
> break;
> }
> break;
> + case IEEE80211_FC0_TYPE_CTL: {
> + u_int8_t *t = (u_int8_t *) wh;
> +
> + printf(": %s", ieee80211_ctl_subtype_name[
> + subtype >> IEEE80211_FC0_SUBTYPE_SHIFT]);
> + if (!vflag)
> + break;
> +
> + /* See 802.11 2012 "8.3.1 Control frames". */
> + t += 2; /* skip Frame Control */
> + switch (subtype) {
> + case IEEE80211_FC0_SUBTYPE_RTS:
> + case IEEE80211_FC0_SUBTYPE_BAR:
> + case IEEE80211_FC0_SUBTYPE_BA:
> + TCHECK2(*t, 2); /* Duration */
> + printf(", duration %dms", (t[0] || t[1] << 8));
> + t += 2;
> + TCHECK2(*t, 6); /* RA */
> + printf(", ra %s", etheraddr_string(t));
> + t += 6;
> + TCHECK2(*t, 6); /* TA */
> + printf(", ta %s", etheraddr_string(t));
> + if (subtype == IEEE80211_FC0_SUBTYPE_BAR ||
> + subtype == IEEE80211_FC0_SUBTYPE_BA) {
> + u_int16_t ctrl;
> +
> + TCHECK2(*t, 2); /* BAR/BA control */
> + ctrl = t[0] | (t[1] << 8);
> + if (ctrl & IEEE80211_BA_ACK_POLICY)
> + printf(", no ack");
> + else
> + printf(", normal ack");
> + if ((ctrl & IEEE80211_BA_MULTI_TID) == 0 &&
> + (ctrl & IEEE80211_BA_COMPRESSED) == 0)
> + printf(", basic variant");
> + else if ((ctrl & IEEE80211_BA_MULTI_TID) &&
> + (ctrl & IEEE80211_BA_COMPRESSED))
> + printf(", multi-tid variant");
> + else if (ctrl & IEEE80211_BA_COMPRESSED)
> + printf(", compressed variant");
> + }
> + break;
> + case IEEE80211_FC0_SUBTYPE_CTS:
> + case IEEE80211_FC0_SUBTYPE_ACK:
> + TCHECK2(*t, 2); /* Duration */
> + printf(", duration %dms", (t[0] || t[1] << 8));
> + t += 2;
> + TCHECK2(*t, 6); /* RA */
> + printf(", ra %s", etheraddr_string(t));
> + break;
> + case IEEE80211_FC0_SUBTYPE_PS_POLL:
> + TCHECK2(*t, 2); /* AID */
> + printf(", aid 0x%x", (t[0] || t[1] << 8));
> + t += 2;
> + TCHECK2(*t, 6); /* BSSID(RA) */
> + printf(", RA %s", etheraddr_string(t));
> + t += 6;
> + TCHECK2(*t, 6); /* TA */
> + printf(", ta %s", etheraddr_string(t));
> + break;
> + }
> + break;
> + }
> default:
> printf(": type#%d", type);
> break;
>
>
