109 lines
2 KiB
C
109 lines
2 KiB
C
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// SPDX-License-Identifier: AGPL-3.0-or-later
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/* PASST - Plug A Simple Socket Transport
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*
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* pcap.c - Packet capture for PASST
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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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*/
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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/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 <net/ethernet.h>
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#include <unistd.h>
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#ifdef DEBUG
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#define PCAP_PREFIX "/tmp/passt_"
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#define PCAP_ISO8601_FORMAT "%FT%H:%M:%SZ"
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#define PCAP_ISO8601_STR "YYYY-MM-ddTHH:mm:ssZ"
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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 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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void pcap(char *pkt, size_t len)
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{
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struct pcap_pkthdr h;
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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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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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write(pcap_fd, &h, sizeof(h));
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write(pcap_fd, pkt, len);
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}
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void pcap_init(void)
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{
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char name[] = PCAP_PREFIX PCAP_ISO8601_STR ".pcap";
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struct timeval tv;
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struct tm *tm;
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gettimeofday(&tv, NULL);
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tm = localtime(&tv.tv_sec);
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strftime(name + strlen(PCAP_PREFIX), sizeof(PCAP_ISO8601_STR) - 1,
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PCAP_ISO8601_FORMAT, tm);
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pcap_fd = open(name, O_WRONLY | O_CREAT | O_APPEND | O_DSYNC,
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S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
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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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write(pcap_fd, &pcap_hdr, sizeof(pcap_hdr));
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}
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#else /* DEBUG */
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void pcap(char *pkt, size_t len) {
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(void)pkt;
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(void)len;
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}
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void pcap_init(void) { }
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#endif
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