hostapd/wlantest/readpcap.c

/*
 * PCAP capture file reader
 * Copyright (c) 2010, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "utils/includes.h"
#include <pcap.h>

#include "utils/common.h"
#include "wlantest.h"


static void write_pcap_with_radiotap(struct wlantest *wt,
				     const u8 *data, size_t data_len)
{
	struct pcap_pkthdr h;
	u8 rtap[] = {
		0x00 /* rev */,
		0x00 /* pad */,
		0x0a, 0x00, /* header len */
		0x02, 0x00, 0x00, 0x00, /* present flags */
		0x00, /* flags */
		0x00 /* pad */
	};
	u8 *buf;
	size_t len;

	if (wt->assume_fcs)
		rtap[8] |= 0x10;

	os_memset(&h, 0, sizeof(h));
	h.ts = wt->write_pcap_time;
	len = sizeof(rtap) + data_len;
	buf = os_malloc(len);
	if (buf == NULL)
		return;
	os_memcpy(buf, rtap, sizeof(rtap));
	os_memcpy(buf + sizeof(rtap), data, data_len);
	h.caplen = len;
	h.len = len;
	pcap_dump(wt->write_pcap_dumper, &h, buf);
	os_free(buf);
}


int read_cap_file(struct wlantest *wt, const char *fname)
{
	char errbuf[PCAP_ERRBUF_SIZE];
	pcap_t *pcap;
	unsigned int count = 0;
	struct pcap_pkthdr *hdr;
	const u_char *data;
	int res;
	int dlt;

	pcap = pcap_open_offline(fname, errbuf);
	if (pcap == NULL) {
		wpa_printf(MSG_ERROR, "Failed to read pcap file '%s': %s",
			   fname, errbuf);
		return -1;
	}
	dlt = pcap_datalink(pcap);
	if (dlt != DLT_IEEE802_11_RADIO && dlt != DLT_PRISM_HEADER &&
	    dlt != DLT_IEEE802_11) {
		wpa_printf(MSG_ERROR, "Unsupported pcap datalink type: %d",
			   dlt);
		pcap_close(pcap);
		return -1;
	}
	wpa_printf(MSG_DEBUG, "pcap datalink type: %d", dlt);

	for (;;) {
		clear_notes(wt);
		os_free(wt->decrypted);
		wt->decrypted = NULL;

		res = pcap_next_ex(pcap, &hdr, &data);
		if (res == -2)
			break; /* No more packets */
		if (res == -1) {
			wpa_printf(MSG_INFO, "pcap_next_ex failure: %s",
				   pcap_geterr(pcap));
			break;
		}
		if (res != 1) {
			wpa_printf(MSG_INFO, "Unexpected pcap_next_ex return "
				   "value %d", res);
			break;
		}

		/* Packet was read without problems */
		wt->frame_num++;
		wpa_printf(MSG_EXCESSIVE, "pcap hdr: ts=%d.%06d "
			   "len=%u/%u",
			   (int) hdr->ts.tv_sec, (int) hdr->ts.tv_usec,
			   hdr->caplen, hdr->len);
		if (wt->write_pcap_dumper) {
			wt->write_pcap_time = hdr->ts;
			if (dlt == DLT_IEEE802_11)
				write_pcap_with_radiotap(wt, data, hdr->caplen);
			else
				pcap_dump(wt->write_pcap_dumper, hdr, data);
			if (wt->pcap_no_buffer)
				pcap_dump_flush(wt->write_pcap_dumper);
		}
		if (hdr->caplen < hdr->len) {
			add_note(wt, MSG_DEBUG, "pcap: Dropped incomplete "
				 "frame (%u/%u captured)",
				 hdr->caplen, hdr->len);
			write_pcapng_write_read(wt, dlt, hdr, data);
			continue;
		}
		count++;
		switch (dlt) {
		case DLT_IEEE802_11_RADIO:
			wlantest_process(wt, data, hdr->caplen);
			break;
		case DLT_PRISM_HEADER:
			wlantest_process_prism(wt, data, hdr->caplen);
			break;
		case DLT_IEEE802_11:
			wlantest_process_80211(wt, data, hdr->caplen);
			break;
		}
		write_pcapng_write_read(wt, dlt, hdr, data);
	}

	pcap_close(pcap);

	wpa_printf(MSG_DEBUG, "Read %s: %u packets", fname, count);

	return 0;
}


int read_wired_cap_file(struct wlantest *wt, const char *fname)
{
	char errbuf[PCAP_ERRBUF_SIZE];
	pcap_t *pcap;
	unsigned int count = 0;
	struct pcap_pkthdr *hdr;
	const u_char *data;
	int res;

	pcap = pcap_open_offline(fname, errbuf);
	if (pcap == NULL) {
		wpa_printf(MSG_ERROR, "Failed to read pcap file '%s': %s",
			   fname, errbuf);
		return -1;
	}

	for (;;) {
		res = pcap_next_ex(pcap, &hdr, &data);
		if (res == -2)
			break; /* No more packets */
		if (res == -1) {
			wpa_printf(MSG_INFO, "pcap_next_ex failure: %s",
				   pcap_geterr(pcap));
			break;
		}
		if (res != 1) {
			wpa_printf(MSG_INFO, "Unexpected pcap_next_ex return "
				   "value %d", res);
			break;
		}

		/* Packet was read without problems */
		wpa_printf(MSG_EXCESSIVE, "pcap hdr: ts=%d.%06d "
			   "len=%u/%u",
			   (int) hdr->ts.tv_sec, (int) hdr->ts.tv_usec,
			   hdr->caplen, hdr->len);
		if (hdr->caplen < hdr->len) {
			wpa_printf(MSG_DEBUG, "pcap: Dropped incomplete frame "
				   "(%u/%u captured)",
				   hdr->caplen, hdr->len);
			continue;
		}
		count++;
		wlantest_process_wired(wt, data, hdr->caplen);
	}

	pcap_close(pcap);

	wpa_printf(MSG_DEBUG, "Read %s: %u packets", fname, count);

	return 0;
}