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hostapd/wlantest/writepcap.c
Jouni Malinen ba2beacc97 wlantest: Add support for writing pcapng files 
The new -n<file> command line argument can be used to request wlantest
to write all read or captured frames into a pcapng file. This is similar
to the -w argument, but with pcapng allowing per-frame comments to be
embedded in the file.

Signed-hostap: Jouni Malinen <j@w1.fi>
2013-05-26 20:58:42 +03:00

324 lines
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/*
* PCAP capture file writer
* 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 <pcap-bpf.h>
#include "utils/common.h"
#include "wlantest.h"
int write_pcap_init(struct wlantest *wt, const char *fname)
{
wt->write_pcap = pcap_open_dead(DLT_IEEE802_11_RADIO, 4000);
if (wt->write_pcap == NULL)
return -1;
wt->write_pcap_dumper = pcap_dump_open(wt->write_pcap, fname);
if (wt->write_pcap_dumper == NULL) {
pcap_close(wt->write_pcap);
wt->write_pcap = NULL;
return -1;
}
wpa_printf(MSG_DEBUG, "Writing PCAP dump to '%s'", fname);
return 0;
}
void write_pcap_deinit(struct wlantest *wt)
{
if (wt->write_pcap_dumper) {
pcap_dump_close(wt->write_pcap_dumper);
wt->write_pcap_dumper = NULL;
}
if (wt->write_pcap) {
pcap_close(wt->write_pcap);
wt->write_pcap = NULL;
}
}
void write_pcap_captured(struct wlantest *wt, const u8 *buf, size_t len)
{
struct pcap_pkthdr h;
if (!wt->write_pcap_dumper)
return;
os_memset(&h, 0, sizeof(h));
gettimeofday(&wt->write_pcap_time, NULL);
h.ts = wt->write_pcap_time;
h.caplen = len;
h.len = len;
pcap_dump(wt->write_pcap_dumper, &h, buf);
}
void write_pcap_decrypted(struct wlantest *wt, const u8 *buf1, size_t len1,
const u8 *buf2, size_t len2)
{
struct pcap_pkthdr h;
u8 rtap[] = {
0x00 /* rev */,
0x00 /* pad */,
0x08, 0x00, /* header len */
0x00, 0x00, 0x00, 0x00 /* present flags */
};
u8 *buf;
size_t len;
if (!wt->write_pcap_dumper && !wt->pcapng)
return;
os_free(wt->decrypted);
len = sizeof(rtap) + len1 + len2;
wt->decrypted = buf = os_malloc(len);
if (buf == NULL)
return;
wt->decrypted_len = len;
os_memcpy(buf, rtap, sizeof(rtap));
if (buf1) {
os_memcpy(buf + sizeof(rtap), buf1, len1);
buf[sizeof(rtap) + 1] &= ~0x40; /* Clear Protected flag */
}
if (buf2)
os_memcpy(buf + sizeof(rtap) + len1, buf2, len2);
if (!wt->write_pcap_dumper)
return;
os_memset(&h, 0, sizeof(h));
h.ts = wt->write_pcap_time;
h.caplen = len;
h.len = len;
pcap_dump(wt->write_pcap_dumper, &h, buf);
}
struct pcapng_section_header {
u32 block_type; /* 0x0a0d0d0a */
u32 block_total_len;
u32 byte_order_magic;
u16 major_version;
u16 minor_version;
u64 section_len;
u32 block_total_len2;
} STRUCT_PACKED;
struct pcapng_interface_description {
u32 block_type; /* 0x00000001 */
u32 block_total_len;
u16 link_type;
u16 reserved;
u32 snap_len;
u32 block_total_len2;
} STRUCT_PACKED;
struct pcapng_enhanced_packet {
u32 block_type; /* 0x00000006 */
u32 block_total_len;
u32 interface_id;
u32 timestamp_high;
u32 timestamp_low;
u32 captured_len;
u32 packet_len;
/* Packet data - aligned to 32 bits */
/* Options (variable) */
/* Block Total Length copy */
} STRUCT_PACKED;
#define PCAPNG_BYTE_ORDER_MAGIC 0x1a2b3c4d
#define PCAPNG_BLOCK_IFACE_DESC 0x00000001
#define PCAPNG_BLOCK_PACKET 0x00000002
#define PCAPNG_BLOCK_SIMPLE_PACKET 0x00000003
#define PCAPNG_BLOCK_NAME_RESOLUTION 0x00000004
#define PCAPNG_BLOCK_INTERFACE_STATISTICS 0x00000005
#define PCAPNG_BLOCK_ENHANCED_PACKET 0x00000006
#define PCAPNG_BLOCK_SECTION_HEADER 0x0a0d0d0a
#define LINKTYPE_IEEE802_11 105
#define LINKTYPE_IEEE802_11_RADIO 127
#define PAD32(a) ((4 - ((a) & 3)) & 3)
#define ALIGN32(a) ((a) + PAD32((a)))
int write_pcapng_init(struct wlantest *wt, const char *fname)
{
struct pcapng_section_header hdr;
struct pcapng_interface_description desc;
wt->pcapng = fopen(fname, "wb");
if (wt->pcapng == NULL)
return -1;
wpa_printf(MSG_DEBUG, "Writing PCAPNG dump to '%s'", fname);
os_memset(&hdr, 0, sizeof(hdr));
hdr.block_type = PCAPNG_BLOCK_SECTION_HEADER;
hdr.block_total_len = sizeof(hdr);
hdr.byte_order_magic = PCAPNG_BYTE_ORDER_MAGIC;
hdr.major_version = 1;
hdr.minor_version = 0;
hdr.section_len = -1;
hdr.block_total_len2 = hdr.block_total_len;
fwrite(&hdr, sizeof(hdr), 1, wt->pcapng);
os_memset(&desc, 0, sizeof(desc));
desc.block_type = PCAPNG_BLOCK_IFACE_DESC;
desc.block_total_len = sizeof(desc);
desc.block_total_len2 = desc.block_total_len;
desc.link_type = LINKTYPE_IEEE802_11_RADIO;
desc.snap_len = 65535;
fwrite(&desc, sizeof(desc), 1, wt->pcapng);
return 0;
}
void write_pcapng_deinit(struct wlantest *wt)
{
if (wt->pcapng) {
fclose(wt->pcapng);
wt->pcapng = NULL;
}
}
static u8 * pcapng_add_comments(struct wlantest *wt, u8 *pos)
{
size_t i;
u16 *len;
if (!wt->num_notes)
return pos;
*((u16 *) pos) = 1 /* opt_comment */;
pos += 2;
len = (u16 *) pos /* length to be filled in */;
pos += 2;
for (i = 0; i < wt->num_notes; i++) {
size_t nlen = os_strlen(wt->notes[i]);
if (i > 0)
*pos++ = '\n';
os_memcpy(pos, wt->notes[i], nlen);
pos += nlen;
}
*len = pos - (u8 *) len - 2;
pos += PAD32(*len);
*((u16 *) pos) = 0 /* opt_endofopt */;
pos += 2;
*((u16 *) pos) = 0;
pos += 2;
return pos;
}
static void write_pcapng_decrypted(struct wlantest *wt)
{
size_t len;
struct pcapng_enhanced_packet *pkt;
u8 *pos;
u32 *block_len;
if (!wt->pcapng || wt->decrypted == NULL)
return;
add_note(wt, MSG_EXCESSIVE, "decrypted version of the previous frame");
len = sizeof(*pkt) + wt->decrypted_len + 100 + notes_len(wt, 32);
pkt = os_zalloc(len);
if (pkt == NULL)
return;
pkt->block_type = PCAPNG_BLOCK_ENHANCED_PACKET;
pkt->interface_id = 0;
pkt->timestamp_high = wt->write_pcapng_time_high;
pkt->timestamp_low = wt->write_pcapng_time_low;
pkt->captured_len = wt->decrypted_len;
pkt->packet_len = wt->decrypted_len;
pos = (u8 *) (pkt + 1);
os_memcpy(pos, wt->decrypted, wt->decrypted_len);
pos += ALIGN32(wt->decrypted_len);
pos = pcapng_add_comments(wt, pos);
block_len = (u32 *) pos;
pos += 4;
*block_len = pkt->block_total_len = pos - (u8 *) pkt;
fwrite(pkt, pos - (u8 *) pkt, 1, wt->pcapng);
os_free(pkt);
}
void write_pcapng_write_read(struct wlantest *wt, int dlt,
struct pcap_pkthdr *hdr, const u8 *data)
{
struct pcapng_enhanced_packet *pkt;
u8 *pos;
u32 *block_len;
u64 timestamp;
size_t len;
if (!wt->pcapng)
return;
len = sizeof(*pkt) + hdr->len + 100 + notes_len(wt, 32);
pkt = os_zalloc(len);
if (pkt == NULL)
return;
pkt->block_type = PCAPNG_BLOCK_ENHANCED_PACKET;
pkt->interface_id = 0;
timestamp = 1000000 * hdr->ts.tv_sec + hdr->ts.tv_usec;
pkt->timestamp_high = timestamp >> 32;
pkt->timestamp_low = timestamp & 0xffffffff;
wt->write_pcapng_time_high = pkt->timestamp_high;
wt->write_pcapng_time_low = pkt->timestamp_low;
pkt->captured_len = hdr->caplen;
pkt->packet_len = hdr->len;
pos = (u8 *) (pkt + 1);
os_memcpy(pos, data, hdr->caplen);
pos += ALIGN32(hdr->caplen);
pos = pcapng_add_comments(wt, pos);
block_len = (u32 *) pos;
pos += 4;
*block_len = pkt->block_total_len = pos - (u8 *) pkt;
fwrite(pkt, pos - (u8 *) pkt, 1, wt->pcapng);
os_free(pkt);
write_pcapng_decrypted(wt);
}
void write_pcapng_captured(struct wlantest *wt, const u8 *buf, size_t len)
{
struct pcap_pkthdr h;
if (!wt->pcapng)
return;
os_memset(&h, 0, sizeof(h));
gettimeofday(&h.ts, NULL);
h.caplen = len;
h.len = len;
write_pcapng_write_read(wt, DLT_IEEE802_11_RADIO, &h, buf);
}
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