apf_run.c

/*
 * Copyright 2016, The Android Open Source Project
 *
 * 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
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// Simple program to try running an APF program against a packet.

#include <libgen.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "apf_interpreter.h"

// Parses hex in "input". Allocates and fills "*output" with parsed bytes.
// Returns length in bytes of "*output".
int parse_hex(char* input, uint8_t** output) {
    int length = strlen(input);
    if (length & 1) {
        fprintf(stderr, "Argument not even number of characters: %s\n", input);
        exit(1);
    }
    length >>= 1;
    *output = malloc(length);
    if (*output == NULL) {
        fprintf(stderr, "Out of memory, tried to allocate %d\n", length);
        exit(1);
    }
    for (int i = 0; i < length; i++) {
        char byte[3] = { input[i*2], input[i*2+1], 0 };
        char* end_ptr;
        (*output)[i] = strtol(byte, &end_ptr, 16);
        if (end_ptr != byte + 2) {
            fprintf(stderr, "Failed to parse hex %s\n", byte);
            exit(1);
        }
    }
    return length;
}

void print_hex(uint8_t* input, int len) {
    for (int i = 0; i < len; ++i) {
        printf("%02x", input[i]);
    }
}

int main(int argc, char* argv[]) {
    if (argc < 3 || argc > 5) {
        fprintf(stderr,
                "Usage: %s <program> <packet> [<data>] [<age>]\n"
                "  program:     APF program, in hex\n"
                "  packet:      Packet to run through program, in hex\n"
                "  data:        Data memory contents, in hex\n"
                "  age:         Age of program in seconds (default: 0)\n",
                basename(argv[0]));
        exit(1);
    }
    uint8_t* program;
    uint32_t program_len = parse_hex(argv[1], &program);
    uint8_t* packet;
    uint32_t packet_len = parse_hex(argv[2], &packet);
    uint8_t* data = NULL;
    uint32_t data_len = argc > 3 ? parse_hex(argv[3], &data) : 0;
    uint32_t filter_age = argc > 4 ? atoi(argv[4]) : 0;

    // Combine the program and data into the unified APF buffer.
    if (data) {
        program = realloc(program, program_len + data_len);
        memcpy(program + program_len, data, data_len);
        free(data);
    }

    uint32_t ram_len = program_len + data_len;
    int ret = accept_packet(program, program_len, ram_len, packet, packet_len,
                            filter_age);
    printf("Packet %sed\n", ret ? "pass" : "dropp");
    if (data_len) {
        printf("Data: ");
        print_hex(program + program_len, data_len);
        printf("\n");
    }
    free(program);
    free(packet);
    return ret;
}