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Ich schrieb einen einfachen Paketempfänger mit Raw-Sockets und ich bekomme seltsame Ausgänge, zB:Raw Socket Paketempfänger in C, merkwürdige Ausgabe
Received packet: size: 124, type: PACKET_HOST (0)
Sender info: Name: n003-000-000-000.static.ge.com, IP: 3.0.0.0
Data:
74 2f 68 3c d1 9f 00 37 b7 d1 5a a7 08 00 45 00 00 6e 00 00 40
00 40 11 b6 e9 c0 a8 01 01 c0 a8 01 44 00 35 94 08 00 5a 3b aa
e1 78 81 80 00 01 00 01 00 00 00 00 01 30 01 30 01 30 01 33 07
69 6e 2d 61 64 64 72 04 61 72 70 61 00 00 0c 00 01 c0 0c 00 0c
00 01 00 00 65 95 00 20 10 6e 30 30 33 2d 30 30 30 2d 30 30 30
2d 30 30 30 06 73 74 61 74 69 63 02 67 65 03 63 6f 6d 00
Wenn ich im Internet bin gerade, die Pakete sind größer, aber Der Hostname und die Adresse bleiben gleich oder fast gleich.
Könnte jemand mir helfen, das Problem zu identifizieren?
Hier ist der Code:
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <linux/if_ether.h>
#include <netdb.h>
#include <linux/if_packet.h>
#include <netinet/ether.h>
#define PACKET_SIZE 1 << 16
void usage();
void packetTypeToStr(int type, char *str);
int main(int argc, char **argv) {
const char *iface_name;
if (argc == 2) {
iface_name = argv[1];
} else if (argc > 2) {
usage();
return 1;
} else {
iface_name = "wlan0";
}
// Opening socket in raw mode
int socketFileDesc = 0;
if ((socketFileDesc = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL))) == -1) {
perror("socket");
return errno;
}
printf("Opened raw socket\n");
// Acquiring the index of the interface
struct ifreq iface;
memset(&iface, 0, sizeof(struct ifreq));
strncpy(iface.ifr_name, iface_name, strlen(iface_name) + 1);
if (ioctl(socketFileDesc, SIOCGIFINDEX, &iface) < 0) {
perror("SIOCGIFINDEX");
usage();
close(socketFileDesc);
return errno;
}
int index = iface.ifr_ifindex;
printf("Index of the interface %s: %d\n", iface_name, index);
// Acquiring the mac address of the interface
struct ifreq iface_mac;
memset(&iface_mac, 0, sizeof(struct ifreq));
strncpy(iface_mac.ifr_name, iface_name, strlen(iface_name) + 1);
if (ioctl(socketFileDesc, SIOCGIFHWADDR, &iface_mac) < 0) {
perror("SIOCGIFHWADDR");
usage();
close(socketFileDesc);
return errno;
}
printf("MAC address of the interface %s: %s\n", iface_name, ether_ntoa((struct ether_addr*)iface_mac.ifr_hwaddr.sa_data));
// Setting interface in promiscuous mode
struct ifreq iface_options;
memset(&iface_options, 0, sizeof(struct ifreq));
strncpy(iface_options.ifr_name, iface_name, strlen(iface_name) + 1);
if (ioctl(socketFileDesc, SIOCGIFFLAGS, &iface_options) < 0) {
perror("SIOCGIFFLAGS");
close(socketFileDesc);
return errno;
}
iface_options.ifr_flags |= IFF_PROMISC;
if (ioctl(socketFileDesc, SIOCSIFFLAGS, &iface_options) < 0) {
perror("SIOCGIFFLAGS");
close(socketFileDesc);
return errno;
}
printf("Interface %s set in promiscuous mode\n", iface_name);
// Binding socket to the interface
struct sockaddr_ll socketAddress;
memset(&socketAddress, 0, sizeof(socketAddress));
socketAddress.sll_family = AF_PACKET;
socketAddress.sll_protocol = htons(ETH_P_ALL);
socketAddress.sll_ifindex = index;
if (bind(socketFileDesc, (struct sockaddr *) &socketAddress, sizeof(socketAddress)) < 0) {
perror("bind");
close(socketFileDesc);
return errno;
}
printf("Socket bound to the interface: %s\nWaiting for packets...\n", iface_name);
// Receiving packets in a loop
while (1) {
ssize_t n = 0;
uint8_t packet[PACKET_SIZE];
bzero(packet, sizeof(packet));
struct sockaddr_in address;
socklen_t length = sizeof(address);
if ((n = recvfrom(socketFileDesc, packet, sizeof(packet), 0, (struct sockaddr *) &address, &length)) < 0) {
perror("recvfrom");
close(socketFileDesc);
return errno;
}
// Null-terminated data
if (n > 0)
packet[n - 1] = '\0';
else
continue;
// IP address
char ip[INET_ADDRSTRLEN];
inet_ntop(AF_INET, &(address.sin_addr), ip, length);
// Host name
struct hostent *host = gethostbyaddr(&(address.sin_addr), length, AF_INET);
if (host == NULL) {
herror("gethostbyaddr");
return h_errno;
}
const char *hostName = host->h_name;
// Packet type
char packetType[BUFSIZ];
int type = ((struct sockaddr_ll *) &address)->sll_pkttype;
packetTypeToStr(type, packetType);
// Printing info and data
printf("\n\nReceived packet: size: %li, type: %s\n"
"Sender info: Name: %s, IP: %s\n",
n, packetType, hostName, ip);
printf("Data:\n");
int i = 0;
for (; i < n; ++i)
printf("%02x ", packet[i]);
}
return 0;
}