| 1 | /* Trivial libtrace program that counts the number of HTTP packets in a trace. |
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| 2 | * Designed to demonstrate the use of trace_get_transport() |
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| 3 | */ |
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| 4 | #include "libtrace.h" |
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| 5 | #include <stdio.h> |
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| 6 | #include <inttypes.h> |
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| 7 | #include <assert.h> |
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| 8 | #include <getopt.h> |
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| 9 | |
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| 10 | uint64_t count = 0; |
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| 11 | |
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| 12 | |
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| 13 | static void per_packet(libtrace_packet_t *packet) |
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| 14 | { |
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| 15 | void *transport; |
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| 16 | uint8_t proto; |
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| 17 | uint32_t remaining; |
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| 18 | libtrace_tcp_t *tcp; |
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| 19 | |
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| 20 | /* Remember that both proto and remaining will be set for us by |
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| 21 | * this function, so we need to pass in pointers to pre-existing |
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| 22 | * variables. Any values in those variables will be ignored and |
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| 23 | * replaced by trace_get_transport |
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| 24 | */ |
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| 25 | transport = trace_get_transport(packet, &proto, &remaining); |
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| 26 | |
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| 27 | /* If the packet does not have a transport header, skip it */ |
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| 28 | if (transport == NULL) |
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| 29 | return; |
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| 30 | |
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| 31 | /* If the transport header is not TCP, skip it */ |
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| 32 | if (proto != 6) |
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| 33 | return; |
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| 34 | |
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| 35 | /* Cast the transport header into a TCP header */ |
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| 36 | tcp = (libtrace_tcp_t *)transport; |
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| 37 | |
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| 38 | /* Check if either port in the TCP header is 80. Note that we have |
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| 39 | * to byteswap the port numbers because we are reading directly out |
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| 40 | * of the zero-copied packet */ |
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| 41 | if ((ntohs(tcp->source) == 80) || (ntohs(tcp->dest) == 80)) |
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| 42 | count += 1; |
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| 43 | } |
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| 44 | |
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| 45 | static void libtrace_cleanup(libtrace_t *trace, libtrace_packet_t *packet) { |
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| 46 | |
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| 47 | /* It's very important to ensure that we aren't trying to destroy |
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| 48 | * a NULL structure, so each of the destroy calls will only occur |
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| 49 | * if the structure exists */ |
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| 50 | if (trace) |
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| 51 | trace_destroy(trace); |
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| 52 | |
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| 53 | if (packet) |
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| 54 | trace_destroy_packet(packet); |
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| 55 | |
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| 56 | } |
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| 57 | |
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| 58 | int main(int argc, char *argv[]) |
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| 59 | { |
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| 60 | /* This is essentially the same main function from readdemo.c */ |
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| 61 | |
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| 62 | libtrace_t *trace = NULL; |
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| 63 | libtrace_packet_t *packet = NULL; |
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| 64 | |
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| 65 | /* Ensure we have at least one argument after the program name */ |
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| 66 | if (argc < 2) { |
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| 67 | fprintf(stderr, "Usage: %s inputURI\n", argv[0]); |
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| 68 | return 1; |
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| 69 | } |
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| 70 | |
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| 71 | packet = trace_create_packet(); |
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| 72 | |
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| 73 | if (packet == NULL) { |
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| 74 | perror("Creating libtrace packet"); |
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| 75 | libtrace_cleanup(trace, packet); |
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| 76 | return 1; |
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| 77 | } |
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| 78 | |
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| 79 | trace = trace_create(argv[1]); |
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| 80 | |
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| 81 | if (trace_is_err(trace)) { |
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| 82 | trace_perror(trace,"Opening trace file"); |
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| 83 | libtrace_cleanup(trace, packet); |
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| 84 | return 1; |
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| 85 | } |
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| 86 | |
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| 87 | if (trace_start(trace) == -1) { |
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| 88 | trace_perror(trace,"Starting trace"); |
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| 89 | libtrace_cleanup(trace, packet); |
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| 90 | return 1; |
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| 91 | } |
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| 92 | |
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| 93 | |
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| 94 | while (trace_read_packet(trace,packet)>0) { |
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| 95 | per_packet(packet); |
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| 96 | } |
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| 97 | |
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| 98 | |
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| 99 | if (trace_is_err(trace)) { |
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| 100 | trace_perror(trace,"Reading packets"); |
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| 101 | libtrace_cleanup(trace, packet); |
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| 102 | return 1; |
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| 103 | } |
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| 104 | |
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| 105 | printf("Packet Count = %" PRIu64 "\n", count); |
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| 106 | |
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| 107 | libtrace_cleanup(trace, packet); |
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| 108 | return 0; |
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| 109 | } |
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| 110 | |
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