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https://passt.top/passt
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ca2749e1bd
In practical terms, passt doesn't benefit from the additional protection offered by the AGPL over the GPL, because it's not suitable to be executed over a computer network. Further, restricting the distribution under the version 3 of the GPL wouldn't provide any practical advantage either, as long as the passt codebase is concerned, and might cause unnecessary compatibility dilemmas. Change licensing terms to the GNU General Public License Version 2, or any later version, with written permission from all current and past contributors, namely: myself, David Gibson, Laine Stump, Andrea Bolognani, Paul Holzinger, Richard W.M. Jones, Chris Kuhn, Florian Weimer, Giuseppe Scrivano, Stefan Hajnoczi, and Vasiliy Ulyanov. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
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 %lu", 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 %lu",
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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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