24410b37a4
Update the low-level helper pcap_frame() to take a struct iovec and offset within it, rather than an explicit pointer and length for the frame. This moves the handling of an offset (to skip vnet_len) from pcap_multiple() to pcap_frame(). This doesn't accomplish a great deal immediately, but will make subsequent changes easier. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
153 lines
3.2 KiB
C
153 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
|
|
/* PASST - Plug A Simple Socket Transport
|
|
* for qemu/UNIX domain socket mode
|
|
*
|
|
* PASTA - Pack A Subtle Tap Abstraction
|
|
* for network namespace/tap device mode
|
|
*
|
|
* pcap.c - Packet capture for PASST/PASTA
|
|
*
|
|
* Copyright (c) 2021 Red Hat GmbH
|
|
* Author: Stefano Brivio <sbrivio@redhat.com>
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/time.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include <fcntl.h>
|
|
#include <time.h>
|
|
#include <errno.h>
|
|
#include <net/ethernet.h>
|
|
#include <netinet/in.h>
|
|
#include <unistd.h>
|
|
#include <net/if.h>
|
|
|
|
#include "util.h"
|
|
#include "passt.h"
|
|
#include "log.h"
|
|
|
|
#define PCAP_VERSION_MINOR 4
|
|
|
|
static int pcap_fd = -1;
|
|
|
|
/* See pcap.h from libpcap, or pcap-savefile(5) */
|
|
static const struct {
|
|
uint32_t magic;
|
|
#define PCAP_MAGIC 0xa1b2c3d4
|
|
|
|
uint16_t major;
|
|
#define PCAP_VERSION_MAJOR 2
|
|
|
|
uint16_t minor;
|
|
#define PCAP_VERSION_MINOR 4
|
|
|
|
int32_t thiszone;
|
|
uint32_t sigfigs;
|
|
uint32_t snaplen;
|
|
|
|
uint32_t linktype;
|
|
#define PCAP_LINKTYPE_ETHERNET 1
|
|
} pcap_hdr = {
|
|
PCAP_MAGIC, PCAP_VERSION_MAJOR, PCAP_VERSION_MINOR, 0, 0, ETH_MAX_MTU,
|
|
PCAP_LINKTYPE_ETHERNET
|
|
};
|
|
|
|
struct pcap_pkthdr {
|
|
uint32_t tv_sec;
|
|
uint32_t tv_usec;
|
|
uint32_t caplen;
|
|
uint32_t len;
|
|
};
|
|
|
|
/**
|
|
* pcap_frame() - Capture a single frame to pcap file with given timestamp
|
|
* @iov: IO vector referencing buffer containing frame (with L2 headers)
|
|
* @offset: Offset of the frame from @iov->iov_base
|
|
* @tv: Timestamp
|
|
*
|
|
* Returns: 0 on success, -errno on error writing to the file
|
|
*/
|
|
static void pcap_frame(const struct iovec *iov, size_t offset,
|
|
const struct timeval *tv)
|
|
{
|
|
size_t len = iov->iov_len - offset;
|
|
struct pcap_pkthdr h;
|
|
|
|
h.tv_sec = tv->tv_sec;
|
|
h.tv_usec = tv->tv_usec;
|
|
h.caplen = h.len = len;
|
|
|
|
if (write(pcap_fd, &h, sizeof(h)) < 0 ||
|
|
write(pcap_fd, (char *)iov->iov_base + offset, len) < 0)
|
|
debug("Cannot log packet, length %zu", len);
|
|
}
|
|
|
|
/**
|
|
* pcap() - Capture a single frame to pcap file
|
|
* @pkt: Pointer to data buffer, including L2 headers
|
|
* @len: L2 packet length
|
|
*/
|
|
void pcap(const char *pkt, size_t len)
|
|
{
|
|
struct iovec iov = { (char *)pkt, len };
|
|
struct timeval tv;
|
|
|
|
if (pcap_fd == -1)
|
|
return;
|
|
|
|
gettimeofday(&tv, NULL);
|
|
pcap_frame(&iov, 0, &tv);
|
|
}
|
|
|
|
/**
|
|
* pcap_multiple() - Capture multiple frames
|
|
* @iov: Array of iovecs, one entry per frame
|
|
* @n: Number of frames to capture
|
|
* @offset: Offset of the frame within each iovec buffer
|
|
*/
|
|
void pcap_multiple(const struct iovec *iov, unsigned int n, size_t offset)
|
|
{
|
|
struct timeval tv;
|
|
unsigned int i;
|
|
|
|
if (pcap_fd == -1)
|
|
return;
|
|
|
|
gettimeofday(&tv, NULL);
|
|
|
|
for (i = 0; i < n; i++)
|
|
pcap_frame(iov + i, offset, &tv);
|
|
}
|
|
|
|
/**
|
|
* pcap_init() - Initialise pcap file
|
|
* @c: Execution context
|
|
*/
|
|
void pcap_init(struct ctx *c)
|
|
{
|
|
int flags = O_WRONLY | O_CREAT | O_TRUNC;
|
|
|
|
if (pcap_fd != -1)
|
|
return;
|
|
|
|
if (!*c->pcap)
|
|
return;
|
|
|
|
flags |= c->foreground ? O_CLOEXEC : 0;
|
|
pcap_fd = open(c->pcap, flags, S_IRUSR | S_IWUSR);
|
|
if (pcap_fd == -1) {
|
|
perror("open");
|
|
return;
|
|
}
|
|
|
|
info("Saving packet capture to %s", c->pcap);
|
|
|
|
if (write(pcap_fd, &pcap_hdr, sizeof(pcap_hdr)) < 0)
|
|
warn("Cannot write PCAP header: %s", strerror(errno));
|
|
}
|