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292 lines
9.0 KiB
292 lines
9.0 KiB
/*
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* Copyright 2016, The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Simple program to try running an APF program against a packet.
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#include <errno.h>
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#include <getopt.h>
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#include <inttypes.h>
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#include <libgen.h>
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#include <limits.h>
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#include <pcap.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "disassembler.h"
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#include "apf_interpreter.h"
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#define __unused __attribute__((unused))
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enum {
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OPT_PROGRAM,
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OPT_PACKET,
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OPT_PCAP,
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OPT_DATA,
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OPT_AGE,
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OPT_TRACE,
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};
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const struct option long_options[] = {{"program", 1, NULL, OPT_PROGRAM},
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{"packet", 1, NULL, OPT_PACKET},
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{"pcap", 1, NULL, OPT_PCAP},
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{"data", 1, NULL, OPT_DATA},
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{"age", 1, NULL, OPT_AGE},
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{"trace", 0, NULL, OPT_TRACE},
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{"help", 0, NULL, 'h'},
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{NULL, 0, NULL, 0}};
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// Parses hex in "input". Allocates and fills "*output" with parsed bytes.
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// Returns length in bytes of "*output".
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size_t parse_hex(const char* input, uint8_t** output) {
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int length = strlen(input);
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if (length & 1) {
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fprintf(stderr, "Argument not even number of characters: %s\n", input);
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exit(1);
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}
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length >>= 1;
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*output = malloc(length);
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if (*output == NULL) {
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fprintf(stderr, "Out of memory, tried to allocate %d\n", length);
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exit(1);
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}
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for (int i = 0; i < length; i++) {
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char byte[3] = { input[i*2], input[i*2+1], 0 };
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char* end_ptr;
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(*output)[i] = strtol(byte, &end_ptr, 16);
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if (end_ptr != byte + 2) {
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fprintf(stderr, "Failed to parse hex %s\n", byte);
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exit(1);
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}
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}
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return length;
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}
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void print_hex(const uint8_t* input, int len) {
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for (int i = 0; i < len; ++i) {
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printf("%02x", input[i]);
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}
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}
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int tracing_enabled = 0;
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void maybe_print_tracing_header() {
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if (!tracing_enabled) return;
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printf(" R0 R1 PC Instruction\n");
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printf("-------------------------------------------------\n");
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}
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// Process packet through APF filter
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void packet_handler(uint8_t* program, uint32_t program_len, uint32_t ram_len,
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const char* pkt, uint32_t filter_age) {
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uint8_t* packet;
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uint32_t packet_len = parse_hex(pkt, &packet);
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maybe_print_tracing_header();
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int ret = accept_packet(program, program_len, ram_len, packet, packet_len,
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filter_age);
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printf("Packet %sed\n", ret ? "pass" : "dropp");
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free(packet);
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}
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void apf_trace_hook(uint32_t pc, const uint32_t* regs, const uint8_t* program, uint32_t program_len,
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const uint8_t* packet __unused, uint32_t packet_len __unused,
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const uint32_t* memory __unused, uint32_t memory_len __unused) {
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if (!tracing_enabled) return;
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printf("%8" PRIx32 " %8" PRIx32 " ", regs[0], regs[1]);
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apf_disassemble(program, program_len, pc);
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}
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// Process pcap file through APF filter and generate output files
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void file_handler(uint8_t* program, uint32_t program_len, uint32_t ram_len, const char* filename,
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uint32_t filter_age) {
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char errbuf[PCAP_ERRBUF_SIZE];
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pcap_t *pcap;
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struct pcap_pkthdr apf_header;
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const uint8_t* apf_packet;
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pcap_dumper_t *passed_dumper, *dropped_dumper;
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const char passed_file[] = "passed.pcap";
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const char dropped_file[] = "dropped.pcap";
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int pass = 0;
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int drop = 0;
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pcap = pcap_open_offline(filename, errbuf);
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if (pcap == NULL) {
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printf("Open pcap file failed.\n");
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exit(1);
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}
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passed_dumper = pcap_dump_open(pcap, passed_file);
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dropped_dumper = pcap_dump_open(pcap, dropped_file);
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if (!passed_dumper || !dropped_dumper) {
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printf("pcap_dump_open(): open output file failed.\n");
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pcap_close(pcap);
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exit(1);
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}
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while ((apf_packet = pcap_next(pcap, &apf_header)) != NULL) {
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maybe_print_tracing_header();
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int result = accept_packet(program, program_len, ram_len, apf_packet,
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apf_header.len, filter_age);
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if (!result){
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drop++;
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pcap_dump((u_char*)dropped_dumper, &apf_header, apf_packet);
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} else {
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pass++;
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pcap_dump((u_char*)passed_dumper, &apf_header, apf_packet);
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}
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}
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printf("%d packets dropped\n", drop);
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printf("%d packets passed\n", pass);
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pcap_dump_close(passed_dumper);
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pcap_dump_close(dropped_dumper);
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pcap_close(pcap);
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}
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void print_usage(char* cmd) {
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fprintf(stderr,
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"Usage: %s --program <program> --pcap <file>|--packet <packet> "
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"[--data <content>] [--age <number>] [--trace]\n"
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" --program APF program, in hex.\n"
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" --pcap Pcap file to run through program.\n"
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" --packet Packet to run through program.\n"
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" --data Data memory contents, in hex.\n"
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" --age Age of program in seconds (default: 0).\n"
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" --trace Enable APF interpreter debug tracing\n"
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" -h, --help Show this message.\n",
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basename(cmd));
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}
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int main(int argc, char* argv[]) {
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uint8_t* program = NULL;
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uint32_t program_len;
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const char* filename = NULL;
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char* packet = NULL;
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uint8_t* data = NULL;
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uint32_t data_len = 0;
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uint32_t filter_age = 0;
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int opt;
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char *endptr;
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while ((opt = getopt_long_only(argc, argv, "h", long_options, NULL)) != -1) {
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switch (opt) {
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case OPT_PROGRAM:
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program_len = parse_hex(optarg, &program);
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break;
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case OPT_PACKET:
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if (!program) {
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printf("<packet> requires <program> first\n\'%s -h or --help\' "
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"for more information\n", basename(argv[0]));
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exit(1);
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}
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if (filename) {
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printf("Cannot use <file> with <packet> \n\'%s -h or --help\' "
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"for more information\n", basename(argv[0]));
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exit(1);
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}
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packet = optarg;
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break;
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case OPT_PCAP:
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if (!program) {
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printf("<file> requires <program> first\n\'%s -h or --help\' "
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"for more information\n", basename(argv[0]));
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exit(1);
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}
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if (packet) {
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printf("Cannot use <packet> with <file>\n\'%s -h or --help\' "
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"for more information\n", basename(argv[0]));
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exit(1);
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}
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filename = optarg;
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break;
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case OPT_DATA:
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data_len = parse_hex(optarg, &data);
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break;
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case OPT_AGE:
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errno = 0;
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filter_age = strtoul(optarg, &endptr, 10);
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if ((errno == ERANGE && filter_age == UINT32_MAX) ||
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(errno != 0 && filter_age == 0)) {
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perror("Error on age option: strtoul");
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exit(1);
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}
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if (endptr == optarg) {
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printf("No digit found in age.\n");
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exit(1);
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}
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break;
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case OPT_TRACE:
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tracing_enabled = 1;
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break;
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case 'h':
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print_usage(argv[0]);
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exit(0);
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break;
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default:
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print_usage(argv[0]);
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exit(1);
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break;
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}
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}
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if (!program) {
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printf("Must have APF program in option.\n");
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exit(1);
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}
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if (!filename && !packet) {
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printf("Missing file or packet after program.\n");
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exit(1);
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}
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// Combine the program and data into the unified APF buffer.
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if (data) {
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program = realloc(program, program_len + data_len);
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memcpy(program + program_len, data, data_len);
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free(data);
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}
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uint32_t ram_len = program_len + data_len;
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if (filename)
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file_handler(program, program_len, ram_len, filename, filter_age);
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else
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packet_handler(program, program_len, ram_len, packet, filter_age);
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if (data_len) {
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printf("Data: ");
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print_hex(program + program_len, data_len);
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printf("\n");
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}
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free(program);
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return 0;
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}
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