| 1 | /* Trivial libtrace program that writes all SMTP packets from a trace into |
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| 2 | * a new separate trace. |
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| 3 | * |
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| 4 | * Designed to demonstrate the use of the libtrace output API |
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| 5 | */ |
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| 6 | #include "libtrace.h" |
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| 7 | #include <stdio.h> |
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| 8 | #include <inttypes.h> |
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| 9 | #include <assert.h> |
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| 10 | #include <getopt.h> |
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| 11 | |
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| 12 | static int per_packet(libtrace_out_t *output, libtrace_packet_t *packet) |
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| 13 | { |
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| 14 | libtrace_tcp_t *tcp; |
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| 15 | |
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| 16 | /* Get the TCP header using trace_get_tcp() */ |
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| 17 | tcp = trace_get_tcp(packet); |
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| 18 | |
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| 19 | /* If the packet does not have a TCP header, skip it */ |
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| 20 | if (tcp == NULL) |
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| 21 | return 0; |
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| 22 | |
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| 23 | /* Check if either port in the TCP header is 25. Note that we |
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| 24 | * have to byteswap the port numbers because we are reading directly |
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| 25 | * out of the zero-copied packet */ |
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| 26 | if ((ntohs(tcp->source) == 25) || (ntohs(tcp->dest) == 25)) { |
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| 27 | /* If we have a match, write the packet to our output trace, |
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| 28 | * being sure to check for errors */ |
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| 29 | if (trace_write_packet(output, packet) == -1) { |
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| 30 | trace_perror_output(output, "Writing packet"); |
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| 31 | return -1; |
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| 32 | } |
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| 33 | } |
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| 34 | return 0; |
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| 35 | } |
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| 36 | |
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| 37 | /* The cleanup function has now been extended to destroy the output trace as |
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| 38 | * well */ |
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| 39 | static void libtrace_cleanup(libtrace_t *trace, libtrace_out_t *output, |
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| 40 | libtrace_packet_t *packet) { |
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| 41 | |
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| 42 | /* It's very important to ensure that we aren't trying to destroy |
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| 43 | * a NULL structure, so each of the destroy calls will only occur |
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| 44 | * if the structure exists */ |
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| 45 | if (trace) |
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| 46 | trace_destroy(trace); |
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| 47 | |
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| 48 | if (output) |
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| 49 | trace_destroy_output(output); |
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| 50 | |
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| 51 | if (packet) |
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| 52 | trace_destroy_packet(packet); |
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| 53 | |
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| 54 | } |
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| 55 | |
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| 56 | int main(int argc, char *argv[]) |
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| 57 | { |
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| 58 | /* Unlike most of the other example programs, this is not a copy and |
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| 59 | * paste job from readdemo.c as we now also have to initalise and |
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| 60 | * start an output trace too */ |
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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 | libtrace_out_t *output = NULL; |
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| 65 | |
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| 66 | /* Check that we have all the required command line arguments */ |
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| 67 | if (argc < 3) { |
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| 68 | fprintf(stderr, "Usage: %s inputURI outputURI\n", argv[0]); |
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| 69 | return 1; |
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| 70 | } |
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| 71 | |
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| 72 | /* Creating the packet structure */ |
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| 73 | packet = trace_create_packet(); |
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| 74 | |
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| 75 | if (packet == NULL) { |
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| 76 | perror("Creating libtrace packet"); |
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| 77 | libtrace_cleanup(trace, output, packet); |
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| 78 | return 1; |
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| 79 | } |
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| 80 | |
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| 81 | /* Creating and starting the INPUT trace */ |
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| 82 | trace = trace_create(argv[1]); |
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| 83 | |
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| 84 | if (trace_is_err(trace)) { |
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| 85 | trace_perror(trace,"Opening trace file"); |
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| 86 | libtrace_cleanup(trace, output, packet); |
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| 87 | return 1; |
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| 88 | } |
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| 89 | |
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| 90 | if (trace_start(trace) == -1) { |
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| 91 | trace_perror(trace,"Starting trace"); |
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| 92 | libtrace_cleanup(trace, output, packet); |
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| 93 | return 1; |
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| 94 | } |
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| 95 | |
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| 96 | /* Creating and starting the OUTPUT trace */ |
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| 97 | output = trace_create_output(argv[2]); |
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| 98 | |
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| 99 | if (trace_is_err_output(output)) { |
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| 100 | trace_perror_output(output,"Opening output trace file"); |
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| 101 | libtrace_cleanup(trace, output, packet); |
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| 102 | return 1; |
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| 103 | } |
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| 104 | |
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| 105 | if (trace_start_output(output) == -1) { |
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| 106 | trace_perror_output(output,"Starting output trace"); |
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| 107 | libtrace_cleanup(trace, output, packet); |
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| 108 | return 1; |
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| 109 | } |
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| 110 | |
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| 111 | while (trace_read_packet(trace,packet)>0) { |
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| 112 | |
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| 113 | /* If something goes wrong when writing packets, we need to |
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| 114 | * catch that error, tidy up and exit */ |
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| 115 | if (per_packet(output, packet) == -1) { |
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| 116 | libtrace_cleanup(trace, output, packet); |
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| 117 | return 1; |
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| 118 | } |
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| 119 | } |
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| 120 | |
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| 121 | /* Checking for any errors that might have occurred while reading the |
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| 122 | * input trace */ |
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| 123 | if (trace_is_err(trace)) { |
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| 124 | trace_perror(trace,"Reading packets"); |
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| 125 | libtrace_cleanup(trace, output, packet); |
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| 126 | return 1; |
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| 127 | } |
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| 128 | |
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| 129 | libtrace_cleanup(trace, output, packet); |
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| 130 | return 0; |
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| 131 | } |
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| 132 | |
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