print-802_11.c

来自「TCPDUMP的C语言源代码,是在数据链路层的应用」· C语言 代码 · 共 1,302 行 · 第 1/3 页

    const u_int8_t **dstp)
{
	if (vflag) {
		if (FC_MORE_DATA(fc))
			printf("More Data ");
		if (FC_MORE_FLAG(fc))
			printf("More Fragments ");
		if (FC_POWER_MGMT(fc))
			printf("Pwr Mgmt ");
		if (FC_RETRY(fc))
			printf("Retry ");
		if (FC_ORDER(fc))
			printf("Strictly Ordered ");
		if (FC_WEP(fc))
			printf("WEP Encrypted ");
		if (FC_TYPE(fc) != T_CTRL || FC_SUBTYPE(fc) != CTRL_PS_POLL)
			printf("%dus ",
			    EXTRACT_LE_16BITS(
			        &((const struct mgmt_header_t *)p)->duration));
	}

	switch (FC_TYPE(fc)) {
	case T_MGMT:
		mgmt_header_print(p, srcp, dstp);
		break;
	case T_CTRL:
		ctrl_header_print(fc, p, srcp, dstp);
		break;
	case T_DATA:
		data_header_print(fc, p, srcp, dstp);
		break;
	default:
		printf("(header) unknown IEEE802.11 frame type (%d)",
		    FC_TYPE(fc));
		*srcp = NULL;
		*dstp = NULL;
		break;
	}
}

#ifndef roundup2
#define	roundup2(x, y)	(((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
#endif

static u_int
ieee802_11_print(const u_char *p, u_int length, u_int caplen, int pad)
{
	u_int16_t fc;
	u_int hdrlen;
	const u_int8_t *src, *dst;
	u_short extracted_ethertype;

	if (caplen < IEEE802_11_FC_LEN) {
		printf("[|802.11]");
		return caplen;
	}

	fc = EXTRACT_LE_16BITS(p);
	hdrlen = extract_header_length(fc);
	if (pad)
		hdrlen = roundup2(hdrlen, 4);

	if (caplen < hdrlen) {
		printf("[|802.11]");
		return hdrlen;
	}

	ieee_802_11_hdr_print(fc, p, &src, &dst);

	/*
	 * Go past the 802.11 header.
	 */
	length -= hdrlen;
	caplen -= hdrlen;
	p += hdrlen;

	switch (FC_TYPE(fc)) {
	case T_MGMT:
		if (!mgmt_body_print(fc,
		    (const struct mgmt_header_t *)(p - hdrlen), p)) {
			printf("[|802.11]");
			return hdrlen;
		}
		break;
	case T_CTRL:
		if (!ctrl_body_print(fc, p - hdrlen)) {
			printf("[|802.11]");
			return hdrlen;
		}
		break;
	case T_DATA:
		if (DATA_FRAME_IS_NULL(FC_SUBTYPE(fc)))
			return hdrlen;	/* no-data frame */
		/* There may be a problem w/ AP not having this bit set */
		if (FC_WEP(fc)) {
			if (!wep_print(p)) {
				printf("[|802.11]");
				return hdrlen;
			}
		} else if (llc_print(p, length, caplen, dst, src,
		    &extracted_ethertype) == 0) {
			/*
			 * Some kinds of LLC packet we cannot
			 * handle intelligently
			 */
			if (!eflag)
				ieee_802_11_hdr_print(fc, p - hdrlen, NULL,
				    NULL);
			if (extracted_ethertype)
				printf("(LLC %s) ",
				    etherproto_string(
				        htons(extracted_ethertype)));
			if (!suppress_default_print)
				default_print(p, caplen);
		}
		break;
	default:
		printf("unknown 802.11 frame type (%d)", FC_TYPE(fc));
		break;
	}

	return hdrlen;
}

/*
 * This is the top level routine of the printer.  'p' points
 * to the 802.11 header of the packet, 'h->ts' is the timestamp,
 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
 * is the number of bytes actually captured.
 */
u_int
ieee802_11_if_print(const struct pcap_pkthdr *h, const u_char *p)
{
	return ieee802_11_print(p, h->len, h->caplen, 0);
}

static int
print_radiotap_field(struct cpack_state *s, u_int32_t bit, int *pad)
{
	union {
		int8_t		i8;
		u_int8_t	u8;
		int16_t		i16;
		u_int16_t	u16;
		u_int32_t	u32;
		u_int64_t	u64;
	} u, u2;
	int rc;

	switch (bit) {
	case IEEE80211_RADIOTAP_FLAGS:
		rc = cpack_uint8(s, &u.u8);
		if (u.u8 & IEEE80211_RADIOTAP_F_DATAPAD)
			*pad = 1;
		break;
	case IEEE80211_RADIOTAP_RATE:
	case IEEE80211_RADIOTAP_DB_ANTSIGNAL:
	case IEEE80211_RADIOTAP_DB_ANTNOISE:
	case IEEE80211_RADIOTAP_ANTENNA:
		rc = cpack_uint8(s, &u.u8);
		break;
	case IEEE80211_RADIOTAP_DBM_ANTSIGNAL:
	case IEEE80211_RADIOTAP_DBM_ANTNOISE:
		rc = cpack_int8(s, &u.i8);
		break;
	case IEEE80211_RADIOTAP_CHANNEL:
		rc = cpack_uint16(s, &u.u16);
		if (rc != 0)
			break;
		rc = cpack_uint16(s, &u2.u16);
		break;
	case IEEE80211_RADIOTAP_FHSS:
	case IEEE80211_RADIOTAP_LOCK_QUALITY:
	case IEEE80211_RADIOTAP_TX_ATTENUATION:
		rc = cpack_uint16(s, &u.u16);
		break;
	case IEEE80211_RADIOTAP_DB_TX_ATTENUATION:
		rc = cpack_uint8(s, &u.u8);
		break;
	case IEEE80211_RADIOTAP_DBM_TX_POWER:
		rc = cpack_int8(s, &u.i8);
		break;
	case IEEE80211_RADIOTAP_TSFT:
		rc = cpack_uint64(s, &u.u64);
		break;
	default:
		/* this bit indicates a field whose
		 * size we do not know, so we cannot
		 * proceed.
		 */
		printf("[0x%08x] ", bit);
		return -1;
	}

	if (rc != 0) {
		printf("[|802.11]");
		return rc;
	}

	switch (bit) {
	case IEEE80211_RADIOTAP_CHANNEL:
		printf("%u MHz ", u.u16);
		if (u2.u16 != 0)
			printf("(0x%04x) ", u2.u16);
		break;
	case IEEE80211_RADIOTAP_FHSS:
		printf("fhset %d fhpat %d ", u.u16 & 0xff, (u.u16 >> 8) & 0xff);
		break;
	case IEEE80211_RADIOTAP_RATE:
		PRINT_RATE("", u.u8, " Mb/s ");
		break;
	case IEEE80211_RADIOTAP_DBM_ANTSIGNAL:
		printf("%ddB signal ", u.i8);
		break;
	case IEEE80211_RADIOTAP_DBM_ANTNOISE:
		printf("%ddB noise ", u.i8);
		break;
	case IEEE80211_RADIOTAP_DB_ANTSIGNAL:
		printf("%ddB signal ", u.u8);
		break;
	case IEEE80211_RADIOTAP_DB_ANTNOISE:
		printf("%ddB noise ", u.u8);
		break;
	case IEEE80211_RADIOTAP_LOCK_QUALITY:
		printf("%u sq ", u.u16);
		break;
	case IEEE80211_RADIOTAP_TX_ATTENUATION:
		printf("%d tx power ", -(int)u.u16);
		break;
	case IEEE80211_RADIOTAP_DB_TX_ATTENUATION:
		printf("%ddB tx power ", -(int)u.u8);
		break;
	case IEEE80211_RADIOTAP_DBM_TX_POWER:
		printf("%ddBm tx power ", u.i8);
		break;
	case IEEE80211_RADIOTAP_FLAGS:
		if (u.u8 & IEEE80211_RADIOTAP_F_CFP)
			printf("cfp ");
		if (u.u8 & IEEE80211_RADIOTAP_F_SHORTPRE)
			printf("short preamble ");
		if (u.u8 & IEEE80211_RADIOTAP_F_WEP)
			printf("wep ");
		if (u.u8 & IEEE80211_RADIOTAP_F_FRAG)
			printf("fragmented ");
		if (u.u8 & IEEE80211_RADIOTAP_F_BADFCS)
			printf("bad-fcs ");
		break;
	case IEEE80211_RADIOTAP_ANTENNA:
		printf("antenna %d ", u.u8);
		break;
	case IEEE80211_RADIOTAP_TSFT:
		printf("%" PRIu64 "us tsft ", u.u64);
		break;
	}
	return 0;
}

static u_int
ieee802_11_radio_print(const u_char *p, u_int length, u_int caplen)
{
#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)
#define	IS_EXTENDED(__p)	\
	    (EXTRACT_LE_32BITS(__p) & BIT(IEEE80211_RADIOTAP_EXT)) != 0

	struct cpack_state cpacker;
	struct ieee80211_radiotap_header *hdr;
	u_int32_t present, next_present;
	u_int32_t *presentp, *last_presentp;
	enum ieee80211_radiotap_type bit;
	int bit0;
	const u_char *iter;
	u_int len;
	int pad;

	if (caplen < sizeof(*hdr)) {
		printf("[|802.11]");
		return caplen;
	}

	hdr = (struct ieee80211_radiotap_header *)p;

	len = EXTRACT_LE_16BITS(&hdr->it_len);

	if (caplen < len) {
		printf("[|802.11]");
		return caplen;
	}
	for (last_presentp = &hdr->it_present;
	     IS_EXTENDED(last_presentp) &&
	     (u_char*)(last_presentp + 1) <= p + len;
	     last_presentp++);

	/* are there more bitmap extensions than bytes in header? */
	if (IS_EXTENDED(last_presentp)) {
		printf("[|802.11]");
		return caplen;
	}

	iter = (u_char*)(last_presentp + 1);

	if (cpack_init(&cpacker, (u_int8_t*)iter, len - (iter - p)) != 0) {
		/* XXX */
		printf("[|802.11]");
		return caplen;
	}

	/* Assume no Atheros padding between 802.11 header and body */
	pad = 0;
	for (bit0 = 0, presentp = &hdr->it_present; presentp <= last_presentp;
	     presentp++, bit0 += 32) {
		for (present = EXTRACT_LE_32BITS(presentp); 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 = (enum ieee80211_radiotap_type)
			    (bit0 + BITNO_32(present ^ next_present));

			if (print_radiotap_field(&cpacker, bit, &pad) != 0)
				goto out;
		}
	}
out:
	return len + ieee802_11_print(p + len, length - len, caplen - len, pad);
#undef BITNO_32
#undef BITNO_16
#undef BITNO_8
#undef BITNO_4
#undef BITNO_2
#undef BIT
}

static u_int
ieee802_11_avs_radio_print(const u_char *p, u_int length, u_int caplen)
{
	u_int32_t caphdr_len;

	if (caplen < 8) {
		printf("[|802.11]");
		return caplen;
	}

	caphdr_len = EXTRACT_32BITS(p + 4);
	if (caphdr_len < 8) {
		/*
		 * Yow!  The capture header length is claimed not
		 * to be large enough to include even the version
		 * cookie or capture header length!
		 */
		printf("[|802.11]");
		return caplen;
	}

	if (caplen < caphdr_len) {
		printf("[|802.11]");
		return caplen;
	}

	return caphdr_len + ieee802_11_print(p + caphdr_len,
	    length - caphdr_len, caplen - caphdr_len, 0);
}

#define PRISM_HDR_LEN		144

#define WLANCAP_MAGIC_COOKIE_BASE 0x80211000
#define WLANCAP_MAGIC_COOKIE_V1	0x80211001
#define WLANCAP_MAGIC_COOKIE_V2	0x80211002

/*
 * For DLT_PRISM_HEADER; like DLT_IEEE802_11, but with an extra header,
 * containing information such as radio information, which we
 * currently ignore.
 *
 * If, however, the packet begins with WLANCAP_MAGIC_COOKIE_V1 or
 * WLANCAP_MAGIC_COOKIE_V2, it's really DLT_IEEE802_11_RADIO_AVS
 * (currently, on Linux, there's no ARPHRD_ type for
 * DLT_IEEE802_11_RADIO_AVS, as there is a ARPHRD_IEEE80211_PRISM
 * for DLT_PRISM_HEADER, so ARPHRD_IEEE80211_PRISM is used for
 * the AVS header, and the first 4 bytes of the header are used to
 * indicate whether it's a Prism header or an AVS header).
 */
u_int
prism_if_print(const struct pcap_pkthdr *h, const u_char *p)
{
	u_int caplen = h->caplen;
	u_int length = h->len;
	u_int32_t msgcode;

	if (caplen < 4) {
		printf("[|802.11]");
		return caplen;
	}

	msgcode = EXTRACT_32BITS(p);
	if (msgcode == WLANCAP_MAGIC_COOKIE_V1 ||
	    msgcode == WLANCAP_MAGIC_COOKIE_V2)
		return ieee802_11_avs_radio_print(p, length, caplen);

	if (caplen < PRISM_HDR_LEN) {
		printf("[|802.11]");
		return caplen;
	}

	return PRISM_HDR_LEN + ieee802_11_print(p + PRISM_HDR_LEN,
	    length - PRISM_HDR_LEN, caplen - PRISM_HDR_LEN, 0);
}

/*
 * For DLT_IEEE802_11_RADIO; like DLT_IEEE802_11, but with an extra
 * header, containing information such as radio information.
 */
u_int
ieee802_11_radio_if_print(const struct pcap_pkthdr *h, const u_char *p)
{
	return ieee802_11_radio_print(p, h->len, h->caplen);
}

/*
 * For DLT_IEEE802_11_RADIO_AVS; like DLT_IEEE802_11, but with an
 * extra header, containing information such as radio information,
 * which we currently ignore.
 */
u_int
ieee802_11_radio_avs_if_print(const struct pcap_pkthdr *h, const u_char *p)
{
	return ieee802_11_avs_radio_print(p, h->len, h->caplen);
}