| 1 | #include <iostream>
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| 2 | #include <stdio.h>
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| 3 | #include <string>
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| 4 | #include <vector>
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| 5 | #include <errno.h>
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| 6 | #include <sys/ioctl.h>
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| 7 | #include <sys/types.h>
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| 8 | #include <sys/time.h>
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| 9 | #include <net/bpf.h>
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| 10 | #include <pcap.h>
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| 11 |
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| 12 | pcap_t* create(const std::string& name,
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| 13 | const std::string& pcapFilter,
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| 14 | uint32_t snapLen, bool promisc);
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| 15 | bool capture(pcap_t * pcapSession);
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| 16 | void close(pcap_t* pcapSession);
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| 17 |
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| 18 |
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| 19 | int main(int argc, char** argv)
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| 20 | {
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| 21 | if (argc != 3)
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| 22 | {
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| 23 | std::cerr << "Usage: libpcaptest <interface> <filter>"
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| 24 | << std::endl;
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| 25 | return 1;
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| 26 | }
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| 27 |
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| 28 | std::string name(argv[1]), filter(argv[2]);
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| 29 | std::cout << "Capturing from '" << name << " with filter "
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| 30 | << filter << std::endl;
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| 31 |
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| 32 | pcap_t * pcapSession = create(name, filter, 128, true);
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| 33 | capture(pcapSession);
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| 34 | close(pcapSession);
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| 35 | return 0;
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| 36 | }
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| 37 |
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| 38 | /**
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| 39 | This is the callback
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| 40 | **/
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| 41 | void test_pcap_handler(u_char* user, const struct pcap_pkthdr* header,
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| 42 | const u_char* pkt_data)
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| 43 | {
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| 44 | std::cout << "Packet captured" << std::endl;
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| 45 | }
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| 46 |
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| 47 | /**
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| 48 | Temporary used since on Windows they forgot to sign as 'const char*'
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| 49 | the filter string provided to pcap_compile...
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| 50 | **/
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| 51 | void duplicateFilterString(const std::string& pcapFilter,
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| 52 | std::vector<char>& dupFilter)
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| 53 | {
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| 54 | dupFilter.clear();
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| 55 | dupFilter.resize(pcapFilter.size()+1, 0);
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| 56 |
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| 57 | for (uint32_t i=0; i<pcapFilter.size(); ++i)
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| 58 | dupFilter[i] = pcapFilter[i];
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| 59 | }
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| 60 |
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| 61 | void close(pcap_t* pcapSession)
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| 62 | {
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| 63 | if (pcapSession)
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| 64 | {
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| 65 | pcap_close(pcapSession);
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| 66 | }
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| 67 | }
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| 68 |
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| 69 |
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| 70 | pcap_t* create(const std::string& name,
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| 71 | const std::string& pcapFilter,
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| 72 | uint32_t snapLen, bool promisc)
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| 73 | {
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| 74 | char errbuf[PCAP_ERRBUF_SIZE];
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| 75 | pcap_t* pcapSession;
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| 76 |
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| 77 | if ((pcapSession = pcap_open_live(name.c_str(),
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| 78 | snapLen, promisc ? 1 : 0, 1000, errbuf)) == NULL)
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| 79 | {
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| 80 | std::cerr << "Failed pcap_open_live because <"
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| 81 | <<errbuf<<">" << std::endl;
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| 82 | return NULL;
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| 83 | }
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| 84 |
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| 85 | // compile the filter if it's been supplied or snapLen is provided
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| 86 | if (pcapFilter.empty()==false || snapLen<65535)
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| 87 | {
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| 88 | // get netmask
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| 89 | bpf_u_int32 pcapNetaddr, pcapMask;
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| 90 | pcap_lookupnet(name.c_str(), &pcapNetaddr, &pcapMask, errbuf);
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| 91 |
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| 92 | struct bpf_program pcapFilterProgram;
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| 93 | std::vector<char> filterDup;
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| 94 | duplicateFilterString(pcapFilter, filterDup);
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| 95 |
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| 96 | if (pcap_compile(pcapSession, &pcapFilterProgram,
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| 97 | &filterDup[0], 1, pcapMask) == -1)
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| 98 | {
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| 99 | std::string error = pcap_geterr(pcapSession);
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| 100 | pcap_close(pcapSession);
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| 101 | std::cerr << "Failed pcap_compile because <"
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| 102 | <<errbuf<<">" << std::endl;
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| 103 | return NULL;
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| 104 | }
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| 105 |
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| 106 | if (pcap_setfilter(pcapSession, &pcapFilterProgram) == -1)
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| 107 | {
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| 108 | std::string error = pcap_geterr(pcapSession);
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| 109 | pcap_freecode(&pcapFilterProgram);
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| 110 | pcap_close(pcapSession);
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| 111 | std::cerr << "Failed pcap_setfilter because <"
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| 112 | <<errbuf<<">" << std::endl;
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| 113 | return NULL;
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| 114 | }
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| 115 |
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| 116 | pcap_freecode(&pcapFilterProgram);
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| 117 | }
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| 118 |
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| 119 | // set session in non blocking mode
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| 120 | if (pcap_setnonblock(pcapSession, 1, errbuf)!=0)
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| 121 | {
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| 122 | pcap_close(pcapSession);
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| 123 | std::cerr << "Failed pcap_setnonblock because <"
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| 124 | <<errbuf<<">" << std::endl;
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| 125 | return NULL;
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| 126 | }
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| 127 |
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| 128 | /*
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| 129 | Enable this for immediate delivery of packets through callback.
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| 130 |
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| 131 | uint32_t v = 1;
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| 132 | if (ioctl(pcap_fileno(pcapSession), BIOCIMMEDIATE, &v) < 0) {
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| 133 | pcap_close(pcapSession);
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| 134 | std::cerr << "Failed ioctl BIOCIMMEDIATE" << std::endl;
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| 135 | return NULL;
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| 136 | }
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| 137 | */
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| 138 |
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| 139 | int dlt;
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| 140 | const char *dlt_name;
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| 141 | dlt = pcap_datalink(pcapSession);
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| 142 | dlt_name = pcap_datalink_val_to_name(dlt);
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| 143 | if (dlt_name == NULL) {
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| 144 | (void)fprintf(stderr,
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| 145 | "listening on %s, link-type %u, capture size %u bytes\n",
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| 146 | name.c_str(), dlt, snapLen);
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| 147 | } else {
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| 148 | (void)fprintf(stderr,
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| 149 | "listening on %s, link-type %s (%s), capture size %u bytes\n",
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| 150 | name.c_str(), dlt_name,
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| 151 | pcap_datalink_val_to_description(dlt), snapLen);
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| 152 | }
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| 153 |
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| 154 | return pcapSession;
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| 155 | }
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| 156 |
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| 157 | bool capture(pcap_t * pcapSession)
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| 158 | {
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| 159 | struct pcap_stat pcapStats;
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| 160 |
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| 161 | while (true)
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| 162 | {
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| 163 | int32_t ret = pcap_dispatch(pcapSession, 100,
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| 164 | test_pcap_handler, (u_char*)NULL);
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| 165 | std::cout << "Read " << ret << " packets" << std::endl;
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| 166 | if (pcap_stats(pcapSession, &pcapStats) != 0)
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| 167 | {
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| 168 | std::string error = pcap_geterr(pcapSession);
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| 169 | std::cerr << "Failed pcap_setnonblock because <"
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| 170 | <<error<<">" << std::endl;
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| 171 | return false;
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| 172 | }
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| 173 | std::cout << "ReceivedPackets " << pcapStats.ps_recv <<
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| 174 | " DroppedPackets " << pcapStats.ps_drop <<
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| 175 | " I/F DroppedPackets " << pcapStats.ps_ifdrop << std::endl;
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| 176 |
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| 177 |
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| 178 | if (ret==-1)
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| 179 | {
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| 180 | std::string error = pcap_geterr(pcapSession);
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| 181 | std::cerr << "Failed pcap_dispatch because <"<<error<<">" << std::endl;
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| 182 | return NULL;
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| 183 | }
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| 184 |
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| 185 |
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| 186 | sleep(5);
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| 187 | }
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| 188 | return true;
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| 189 | }
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