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https://passt.top/passt
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06559048e7
Types size_t and ssize_t are not necessarily long, it depends on the architecture. Signed-off-by: Stefano Brivio <sbrivio@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
159 lines
3.2 KiB
C
159 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* PASST - Plug A Simple Socket Transport
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* for qemu/UNIX domain socket mode
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*
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* PASTA - Pack A Subtle Tap Abstraction
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* for network namespace/tap device mode
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*
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* pcap.c - Packet capture for PASST/PASTA
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*
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* Copyright (c) 2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#include <stdio.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <time.h>
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#include <errno.h>
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#include <net/ethernet.h>
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#include <netinet/in.h>
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#include <unistd.h>
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#include <net/if.h>
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#include "util.h"
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#include "passt.h"
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#include "log.h"
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#define PCAP_VERSION_MINOR 4
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static int pcap_fd = -1;
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/* See pcap.h from libpcap, or pcap-savefile(5) */
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static const struct {
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uint32_t magic;
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#define PCAP_MAGIC 0xa1b2c3d4
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uint16_t major;
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#define PCAP_VERSION_MAJOR 2
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uint16_t minor;
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#define PCAP_VERSION_MINOR 4
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int32_t thiszone;
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uint32_t sigfigs;
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uint32_t snaplen;
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uint32_t linktype;
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#define PCAP_LINKTYPE_ETHERNET 1
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} pcap_hdr = {
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PCAP_MAGIC, PCAP_VERSION_MAJOR, PCAP_VERSION_MINOR, 0, 0, ETH_MAX_MTU,
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PCAP_LINKTYPE_ETHERNET
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};
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struct pcap_pkthdr {
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uint32_t tv_sec;
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uint32_t tv_usec;
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uint32_t caplen;
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uint32_t len;
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};
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/**
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* pcap_frame() - Capture a single frame to pcap file with given timestamp
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* @pkt: Pointer to data buffer, including L2 headers
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* @len: L2 packet length
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* @tv: Timestamp
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*
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* Returns: 0 on success, -errno on error writing to the file
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*/
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static int pcap_frame(const char *pkt, size_t len, const struct timeval *tv)
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{
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struct pcap_pkthdr h;
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h.tv_sec = tv->tv_sec;
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h.tv_usec = tv->tv_usec;
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h.caplen = h.len = len;
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if (write(pcap_fd, &h, sizeof(h)) < 0 || write(pcap_fd, pkt, len) < 0)
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return -errno;
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return 0;
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}
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/**
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* pcap() - Capture a single frame to pcap file
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* @pkt: Pointer to data buffer, including L2 headers
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* @len: L2 packet length
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*/
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void pcap(const char *pkt, size_t len)
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{
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struct timeval tv;
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if (pcap_fd == -1)
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return;
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gettimeofday(&tv, NULL);
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if (pcap_frame(pkt, len, &tv) != 0)
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debug("Cannot log packet, length %zu", len);
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}
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/**
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* pcap_multiple() - Capture multiple frames
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* @iov: Array of iovecs, one entry per frame
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* @n: Number of frames to capture
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* @offset: Offset of the frame within each iovec buffer
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*/
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void pcap_multiple(const struct iovec *iov, unsigned int n, size_t offset)
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{
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struct timeval tv;
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unsigned int i;
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if (pcap_fd == -1)
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return;
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gettimeofday(&tv, NULL);
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for (i = 0; i < n; i++) {
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if (pcap_frame((char *)iov[i].iov_base + offset,
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iov[i].iov_len - offset, &tv) != 0) {
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debug("Cannot log packet, length %zu",
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iov->iov_len - offset);
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return;
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}
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}
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}
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/**
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* pcap_init() - Initialise pcap file
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* @c: Execution context
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*/
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void pcap_init(struct ctx *c)
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{
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int flags = O_WRONLY | O_CREAT | O_TRUNC;
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if (pcap_fd != -1)
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return;
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if (!*c->pcap)
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return;
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flags |= c->foreground ? O_CLOEXEC : 0;
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pcap_fd = open(c->pcap, flags, S_IRUSR | S_IWUSR);
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if (pcap_fd == -1) {
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perror("open");
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return;
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}
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info("Saving packet capture to %s", c->pcap);
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if (write(pcap_fd, &pcap_hdr, sizeof(pcap_hdr)) < 0)
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warn("Cannot write PCAP header: %s", strerror(errno));
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}
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