diff options
Diffstat (limited to 'rdns_scan/zmap4rdns/src/recv-pcap.c')
| -rw-r--r-- | rdns_scan/zmap4rdns/src/recv-pcap.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/rdns_scan/zmap4rdns/src/recv-pcap.c b/rdns_scan/zmap4rdns/src/recv-pcap.c new file mode 100644 index 0000000..cc59cdd --- /dev/null +++ b/rdns_scan/zmap4rdns/src/recv-pcap.c @@ -0,0 +1,159 @@ +/* + * ZMap Copyright 2013 Regents of the University of Michigan + * + * Licensed under the Apache License, Version 2.0 (the "License"); you may not + * use this file except in compliance with the License. You may obtain a copy + * of the License at http://www.apache.org/licenses/LICENSE-2.0 + */ + +#include "recv.h" + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include <pthread.h> +#include <assert.h> + +#include "../lib/includes.h" +#include "../lib/logger.h" + +#include <pcap.h> +#include <pcap/pcap.h> +#if defined __linux__ && __linux__ +#include <pcap/sll.h> +#endif + +#include "recv-internal.h" +#include "state.h" + +#include "probe_modules/probe_modules.h" + +#define PCAP_PROMISC 1 +#define PCAP_TIMEOUT 1000 + +static pcap_t *pc = NULL; + +void packet_cb(u_char __attribute__((__unused__)) * user, + const struct pcap_pkthdr *p, const u_char *bytes) +{ + struct timespec ts; + if (!p) { + return; + } + if (zrecv.filter_success >= zconf.max_results) { + // Libpcap can process multiple packets per pcap_dispatch; + // we need to throw out results once we've + // gotten our --max-results worth. + return; + } + + // length of entire packet captured by libpcap + uint32_t buflen = (uint32_t)p->caplen; + ts.tv_sec = p->ts.tv_sec; + ts.tv_nsec = p->ts.tv_usec * 1000; + handle_packet(buflen, bytes, ts); +} + +#define BPFLEN 1024 + +void recv_init() +{ + char bpftmp[BPFLEN]; + char errbuf[PCAP_ERRBUF_SIZE]; + + pc = pcap_open_live(zconf.iface, zconf.probe_module->pcap_snaplen, + PCAP_PROMISC, PCAP_TIMEOUT, errbuf); + if (pc == NULL) { + log_fatal("recv", "could not open device %s: %s", zconf.iface, + errbuf); + } + switch (pcap_datalink(pc)) { + case DLT_EN10MB: + log_debug("recv", "Data link layer Ethernet"); + zconf.data_link_size = sizeof(struct ether_header); + break; + case DLT_RAW: + log_info("recv", "Data link RAW"); + zconf.data_link_size = 0; + break; +#if defined __linux__ && __linux__ + case DLT_LINUX_SLL: + log_info("recv", "Data link cooked socket"); + zconf.data_link_size = SLL_HDR_LEN; + break; +#endif + default: + log_error("recv", "unknown data link layer"); + } + + struct bpf_program bpf; + + if (!zconf.send_ip_pkts) { + snprintf(bpftmp, sizeof(bpftmp) - 1, + "not ether src %02x:%02x:%02x:%02x:%02x:%02x", + zconf.hw_mac[0], zconf.hw_mac[1], zconf.hw_mac[2], + zconf.hw_mac[3], zconf.hw_mac[4], zconf.hw_mac[5]); + assert(strlen(zconf.probe_module->pcap_filter) + 10 < + (BPFLEN - strlen(bpftmp))); + } else { + bpftmp[0] = 0; + } + if (zconf.probe_module->pcap_filter) { + if (!zconf.send_ip_pkts) { + strcat(bpftmp, " and ("); + } else { + strcat(bpftmp, "("); + } + strcat(bpftmp, zconf.probe_module->pcap_filter); + strcat(bpftmp, ")"); + } + if (strcmp(bpftmp, "")) { + if (pcap_compile(pc, &bpf, bpftmp, 1, 0) < 0) { + log_fatal("recv", "couldn't compile filter"); + } + if (pcap_setfilter(pc, &bpf) < 0) { + log_fatal("recv", "couldn't install filter"); + } + } + // set pcap_dispatch to not hang if it never receives any packets + // this could occur if you ever scan a small number of hosts as + // documented in issue #74. + if (pcap_setnonblock(pc, 1, errbuf) == -1) { + log_fatal("recv", "pcap_setnonblock error:%s", errbuf); + } +} + +void recv_packets() +{ + int ret = pcap_dispatch(pc, -1, packet_cb, NULL); + if (ret == -1) { + log_fatal("recv", "pcap_dispatch error"); + } else if (ret == 0) { + usleep(1000); + } +} + +void recv_cleanup() +{ + pcap_close(pc); + pc = NULL; +} + +int recv_update_stats(void) +{ + if (!pc) { + return EXIT_FAILURE; + } + struct pcap_stat pcst; + if (pcap_stats(pc, &pcst)) { + log_error("recv", "unable to retrieve pcap statistics: %s", + pcap_geterr(pc)); + return EXIT_FAILURE; + } else { + zrecv.pcap_recv = pcst.ps_recv; + zrecv.pcap_drop = pcst.ps_drop; + zrecv.pcap_ifdrop = pcst.ps_ifdrop; + } + return EXIT_SUCCESS; +} |