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/*
* Copyright (c) 2017 Cisco and/or its affiliates.
* 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <ifaddrs.h>
#include <assert.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <netinet/in.h>
typedef uint8_t u_char;
typedef uint16_t u_short;
typedef uint32_t u_int;
#include <pcap.h>
#define ETHERTYPE 0x0801
struct _packet {
u_int8_t dst[6];
u_int8_t src[6];
u_int16_t ethertype;
u_int8_t data[0];
} __attribute__((packed));
static void send_file(pcap_t *handle, uint8_t smac[], uint8_t dmac[], const char *filename);
static
void
printhex(u_int8_t *buffer, int length)
{
int i;
for (i = 0; i < length; i++) {
printf("%02X", buffer[i]);
}
}
static void
send_file(pcap_t *handle, uint8_t smac[], uint8_t dmac[], const char *filename)
{
struct stat statbuf;
struct _packet *packet = malloc(1500);
memset(packet, 0, 1500);
int fd = open(filename, O_RDONLY);
if (fd < 0) {
perror("Error opening file: ");
abort();
}
if (fstat(fd, &statbuf) < 0) {
perror("fstat error");
abort();
}
uint8_t *src = mmap(0, statbuf.st_size, PROT_READ, MAP_SHARED, fd, 0);
if (src == MAP_FAILED) {
perror("mmap error");
abort();
}
assert(statbuf.st_size <= 1500);
size_t len = sizeof(struct _packet) + statbuf.st_size;
printf("Sending config/query size %zu\n", len);
memcpy(packet->dst, dmac, 6);
memcpy(packet->src, smac, 6);
packet->ethertype = htons(ETHERTYPE);
memcpy(packet->data, src, statbuf.st_size);
int x = pcap_inject(handle, packet, len);
printf("%s wrote %d bytes\n", __func__, x);
free(packet);
}
static
void
get_mac_address(const char *deviceName, u_int8_t *mac)
{
struct ifaddrs *ifap;
struct ifaddrs *next;
int x = getifaddrs(&ifap);
if (x != 0) {
perror("getifaddrs");
exit(EXIT_FAILURE);
}
next = ifap;
while (next != NULL) {
#if defined(__APPLE__)
if (strstr(deviceName, next->ifa_name) != NULL && next->ifa_addr->sa_family == AF_LINK)
#elif defined(__linux__)
if (strstr(deviceName, next->ifa_name) != NULL && next->ifa_addr->sa_family == AF_PACKET)
#else
#error Unsupported platform
#endif
{
memcpy(mac, next->ifa_addr->sa_data + 9, 6);
break;
}
next = next->ifa_next;
}
freeifaddrs(ifap);
}
static void
macStringToArray(const char *string, size_t outputLength, uint8_t output[])
{
assert(outputLength == 6);
sscanf(string, "%02x:%02x:%02x:%02x:%02x:%02x", &output[0], &output[1], &output[2], &output[3], &output[4], &output[5]);
}
int
main(int argc, const char *argv[])
{
if (argc != 4 || argv[1][0] == '-') {
printf("usage: ethersend dev dst filename\n");
printf("\n");
printf("Will send filename as the payload of an ethernet frame to dst\n");
printf("\n");
printf("example: ethersend eth0 a8:20:66:3b:30:bc interest.bin\n");
printf("\n");
exit(EXIT_FAILURE);
}
pcap_t *handle; /* Session handle */
const char *dev = argv[1]; /* The device to sniff on */
char errbuf[PCAP_ERRBUF_SIZE]; /* Error string */
struct bpf_program fp; /* The compiled filter */
char filter_exp[1024]; /* The filter expression */
bpf_u_int32 mask; /* Our netmask */
bpf_u_int32 net; /* Our IP */
sprintf(filter_exp, "ether proto 0x%04X", ETHERTYPE);
printf("dev = %s\n", dev);
/* Find the properties for the device */
if (pcap_lookupnet(dev, &net, &mask, errbuf) == -1) {
fprintf(stderr, "Couldn't get netmask for device %s: %s\n", dev, errbuf);
net = 0;
mask = 0;
}
u_int8_t mymac[6];
get_mac_address(dev, mymac);
printf("My mac address: "); printhex(mymac, 6); printf("\n");
u_int8_t dmac[6];
macStringToArray(argv[2], 6, dmac);
printf("dmac address : "); printhex(dmac, 6); printf("\n");
/* Open the session in promiscuous mode */
handle = pcap_open_live(dev, 1500, 1, 1000, errbuf);
if (handle == NULL) {
fprintf(stderr, "Couldn't open device %s: %s\n", dev, errbuf);
return (2);
}
/* Compile and apply the filter */
if (pcap_compile(handle, &fp, filter_exp, 0, net) == -1) {
fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle));
return (2);
}
if (pcap_setfilter(handle, &fp) == -1) {
fprintf(stderr, "Couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle));
return (2);
}
send_file(handle, mymac, dmac, argv[3]);
pcap_close(handle);
return (0);
}
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