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apps/tcpdump: Support capture RAW IP interfaces like TUN

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Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
This commit is contained in:
Zhe Weng 2024-02-19 11:30:35 +08:00 committed by Xiang Xiao
parent be74e34ede
commit 9236d9a2f4
1 changed files with 36 additions and 4 deletions
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40
system/tcpdump/tcpdump.c
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@ -27,9 +27,11 @@
#include <errno.h>
#include <fcntl.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netpacket/packet.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <unistd.h>
@ -48,7 +50,10 @@
#define DEFAULT_SNAPLEN 262144
#define LINKTYPE_ETHERNET 1
/* https://www.tcpdump.org/linktypes.html */
#define LINKTYPE_ETHERNET 1 /* IEEE 802.3 Ethernet */
#define LINKTYPE_RAW 101 /* Raw IP */
/****************************************************************************
* Private Types
@ -86,6 +91,7 @@ struct tcpdump_cfgs_s
int fd;
int sd;
uint32_t snaplen;
uint32_t linktype;
};
/****************************************************************************
@ -111,7 +117,7 @@ static void sigexit(int signo)
* Name: write_filehdr
****************************************************************************/
static int write_filehdr(int fd, uint32_t snaplen)
static int write_filehdr(int fd, uint32_t snaplen, uint32_t linktype)
{
/* No need to change byte order of any field, reader will swap all fields
* if magic number is in swapped order.
@ -125,7 +131,7 @@ static int write_filehdr(int fd, uint32_t snaplen)
0, /* thiszone */
0, /* sigfigs */
snaplen, /* snaplen */
LINKTYPE_ETHERNET /* linktype */
linktype /* linktype */
};
/* Write hdr into file. */
@ -203,6 +209,30 @@ static int socket_open(int ifindex)
return sd;
}
/****************************************************************************
* Name: get_linktype
****************************************************************************/
static uint32_t get_linktype(FAR const char *ifname)
{
struct ifreq req;
uint32_t ret = LINKTYPE_RAW;
int sockfd = socket(NET_SOCK_FAMILY, NET_SOCK_TYPE, NET_SOCK_PROTOCOL);
if (sockfd >= 0)
{
strlcpy(req.ifr_name, ifname, IFNAMSIZ);
if (ioctl(sockfd, SIOCGIFHWADDR, (unsigned long)&req) >= 0 &&
req.ifr_hwaddr.sa_family == ARPHRD_ETHER)
{
ret = LINKTYPE_ETHERNET;
}
close(sockfd);
}
return ret;
}
/****************************************************************************
* Name: do_capture
****************************************************************************/
@ -215,7 +245,7 @@ static void do_capture(FAR const struct tcpdump_cfgs_s *cfgs)
/* Write file header */
if (write_filehdr(cfgs->fd, cfgs->snaplen) < 0)
if (write_filehdr(cfgs->fd, cfgs->snaplen, cfgs->linktype) < 0)
{
return;
}
@ -306,6 +336,8 @@ int main(int argc, FAR char *argv[])
cfgs.snaplen = DEFAULT_SNAPLEN;
}
cfgs.linktype = get_linktype(args.interface->sval[0]);
do_capture(&cfgs);
close(cfgs.sd);