/****************************************************************************
* apps/system/tcpdump/tcpdump.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <errno.h>
#include <fcntl.h>
#include <net/if.h>
#include <netpacket/packet.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <nuttx/net/netconfig.h>
#include "argtable3.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define TCPDUMP_MAGIC 0xa1b23c4d /* nanosecond-resolution */
#define TCPDUMP_VERSION_MAJOR 2
#define TCPDUMP_VERSION_MINOR 4
#define DEFAULT_SNAPLEN 262144
#define LINKTYPE_ETHERNET 1
/****************************************************************************
* Private Types
****************************************************************************/
struct pcap_filehdr_s
{
uint32_t magic; /* magic number */
uint16_t version_major; /* major version number */
uint16_t version_minor; /* minor version number */
int32_t thiszone; /* GMT to local correction; this is always 0 */
uint32_t sigfigs; /* accuracy of timestamps; this is always 0 */
uint32_t snaplen; /* max length saved portion of each pkt */
uint32_t linktype; /* data link type (LINKTYPE_*) */
};
struct pcap_pkthdr_s
{
uint32_t ts_sec; /* timestamp seconds */
uint32_t ts_nsec; /* timestamp nanoseconds */
uint32_t caplen; /* length of portion present */
uint32_t len; /* length of this packet (off wire) */
};
struct tcpdump_args_s
{
FAR struct arg_str *interface;
FAR struct arg_str *file;
FAR struct arg_int *snaplen;
FAR struct arg_end *end;
};
struct tcpdump_cfgs_s
{
int fd;
int sd;
uint32_t snaplen;
};
/****************************************************************************
* Private Data
****************************************************************************/
static volatile bool g_exiting;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sigexit
****************************************************************************/
static void sigexit(int signo)
{
g_exiting = true;
}
/****************************************************************************
* Name: write_filehdr
****************************************************************************/
static int write_filehdr(int fd, uint32_t snaplen)
{
/* No need to change byte order of any field, reader will swap all fields
* if magic number is in swapped order.
*/
struct pcap_filehdr_s hdr =
{
TCPDUMP_MAGIC, /* magic */
TCPDUMP_VERSION_MAJOR, /* version_major */
TCPDUMP_VERSION_MINOR, /* version_minor */
0, /* thiszone */
0, /* sigfigs */
snaplen, /* snaplen */
LINKTYPE_ETHERNET /* linktype */
};
/* Write hdr into file. */
if (write(fd, &hdr, sizeof(hdr)) < 0)
{
perror("ERROR: write() failed");
return -errno;
}
return OK;
}
/****************************************************************************
* Name: write_packet
****************************************************************************/
static int write_packet(int fd, uint32_t snaplen, uint32_t pkt_len,
FAR const void *buf, FAR const struct timespec *ts)
{
struct pcap_pkthdr_s hdr =
{
ts->tv_sec, /* ts_sec */
ts->tv_nsec, /* ts_nsec */
MIN(snaplen, pkt_len), /* caplen */
pkt_len /* len */
};
/* Write hdr into file. */
if (write(fd, &hdr, sizeof(hdr)) < 0)
{
perror("ERROR: write() failed");
return -errno;
}
/* Write pkt into file. */
if (write(fd, buf, hdr.caplen) < 0)
{
perror("ERROR: write() failed");
return -errno;
}
return OK;
}
/****************************************************************************
* Name: socket_open
****************************************************************************/
static int socket_open(int ifindex)
{
int sd;
struct sockaddr_ll addr;
sd = socket(PF_PACKET, SOCK_RAW, 0);
if (sd < 0)
{
perror("ERROR: failed to create packet socket");
return -errno;
}
/* Prepare sockaddr struct */
addr.sll_family = AF_PACKET;
addr.sll_ifindex = ifindex;
if (bind(sd, (FAR const struct sockaddr *)&addr, sizeof(addr)) < 0)
{
perror("ERROR: binding socket failed");
close(sd);
return -errno;
}
return sd;
}
/****************************************************************************
* Name: do_capture
****************************************************************************/
static void do_capture(FAR const struct tcpdump_cfgs_s *cfgs)
{
ssize_t len;
uint8_t buf[MAX_NETDEV_PKTSIZE];
struct timespec ts;
/* Write file header */
if (write_filehdr(cfgs->fd, cfgs->snaplen) < 0)
{
return;
}
/* Dump packets */
while ((len = read(cfgs->sd, buf, sizeof(buf))) >= 0 && !g_exiting)
{
if (len == 0)
{
continue;
}
if (clock_gettime(CLOCK_REALTIME, &ts) < 0)
{
perror("ERROR: clock_gettime() failed");
return;
}
if (write_packet(cfgs->fd, cfgs->snaplen, len, buf, &ts) < 0)
{
return;
}
}
if (!g_exiting)
{
perror("ERROR: read() failed");
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
int main(int argc, FAR char *argv[])
{
int ifindex;
int nerrors;
struct tcpdump_cfgs_s cfgs;
struct tcpdump_args_s args;
g_exiting = false;
signal(SIGINT, sigexit);
args.interface = arg_str1("i", "interface", "interface", "Capture device");
args.file = arg_str1("w", NULL, "file", "Path to dump file");
args.snaplen = arg_int0("s", "snapshot-length", "snaplen",
"Max dump length of each packet");
args.end = arg_end(3);
nerrors = arg_parse(argc, argv, (FAR void**)&args);
if (nerrors != 0)
{
arg_print_errors(stdout, args.end, argv[0]);
printf("Usage:\n");
arg_print_glossary(stdout, (FAR void**)&args, " %-30s %s\n");
return 0;
}
ifindex = if_nametoindex(args.interface->sval[0]);
if (ifindex == 0)
{
printf("Failed to get index of device %s\n", args.interface->sval[0]);
return 0;
}
cfgs.fd = open(args.file->sval[0], O_WRONLY | O_CREAT | O_TRUNC, 0644);
if (cfgs.fd < 0)
{
perror("ERROR: open() failed");
return 0;
}
cfgs.sd = socket_open(ifindex);
if (cfgs.sd < 0)
{
close(cfgs.fd);
return 0;
}
if (args.snaplen->count > 0)
{
cfgs.snaplen = *args.snaplen->ival;
}
else
{
cfgs.snaplen = DEFAULT_SNAPLEN;
}
do_capture(&cfgs);
close(cfgs.sd);
close(cfgs.fd);
return 0;
}