使用c socket编程进行arp请求和回复 [英] arp request and reply using c socket programming
问题描述
我正在尝试在 Linux (Ubuntu)
中使用 c 编程来接收和发送 arp 数据包我的程序运行良好(即运行时没有任何错误)，但我无法使用 Wireshark 跟踪数据包.
I am trying to receive and send arp packets using c programming in Linux (Ubuntu)
My program works fine (i.e. runs without any error), but I cannot trace the packets using Wireshark.
源代码:
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <asm/types.h>
#include <math.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#define BUF_SIZE 42
#define DEVICE "eth0"
#define ETH_P_NULL 0x0
#define ETH_MAC_LEN ETH_ALEN
#define ETH_ARP 0x0806
int s = 0; /*Socketdescriptor*/
void* buffer = NULL;
long total_packets = 0;
long answered_packets = 0;
void sigint(int signum);
struct __attribute__((packed)) arp_header
{
unsigned short arp_hd;
unsigned short arp_pr;
unsigned char arp_hdl;
unsigned char arp_prl;
unsigned short arp_op;
unsigned char arp_sha[6];
unsigned char arp_spa[4];
unsigned char arp_dha[6];
unsigned char arp_dpa[4];
};
int main(void) {
buffer = (void*)malloc(BUF_SIZE); /*Buffer for Ethernet Frame*/
unsigned char* etherhead = buffer; /*Pointer to Ethenet Header*/
struct ethhdr *eh = (struct ethhdr *)etherhead; /*Another pointer to
ethernet header*/
unsigned char* arphead = buffer + 14;
struct arp_header *ah;
unsigned char src_mac[6]; /*our MAC address*/
struct ifreq ifr;
struct sockaddr_ll socket_address;
int ifindex = 0; /*Ethernet Interface index*/
int i;
int length; /*length of received packet*/
int sent;
printf("Server started, entering initialiation phase...
");
/*open socket*/
s = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (s == -1) {
perror("socket():");
exit(1);
}
printf("Successfully opened socket: %i
", s);
/*retrieve ethernet interface index*/
strncpy(ifr.ifr_name, DEVICE, IFNAMSIZ);
if (ioctl(s, SIOCGIFINDEX, &ifr) == -1) {
perror("SIOCGIFINDEX");
exit(1);
}
ifindex = ifr.ifr_ifindex;
printf("Successfully got interface index: %i
", ifindex);
/*retrieve corresponding MAC*/
if (ioctl(s, SIOCGIFHWADDR, &ifr) == -1) {
perror("SIOCGIFINDEX");
exit(1);
}
for (i = 0; i < 6; i++) {
src_mac[i] = ifr.ifr_hwaddr.sa_data[i];
}
printf("Successfully got our MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
src_mac[0],src_mac[1],src_mac[2],src_mac[3],src_mac[4],src_mac[5]);
/*prepare sockaddr_ll*/
socket_address.sll_family = PF_PACKET;
socket_address.sll_protocol = htons(ETH_P_IP);
socket_address.sll_ifindex = ifindex;
socket_address.sll_hatype = ARPHRD_ETHER;
socket_address.sll_pkttype = PACKET_OTHERHOST;
socket_address.sll_halen = 0;
socket_address.sll_addr[6] = 0x00;
socket_address.sll_addr[7] = 0x00;
/*establish signal handler*/
signal(SIGINT, sigint);
printf("Successfully established signal handler for SIGINT
");
printf("We are in production state, waiting for incoming packets....
");
while (1) {
/*Wait for incoming packet...*/
length = recvfrom(s, buffer, BUF_SIZE, 0, NULL, NULL);
if (length == -1)
{
perror("recvfrom():");
exit(1);
}
if(htons(eh->h_proto) == 0x806)
{
unsigned char buf_arp_dha[6];
unsigned char buf_arp_dpa[4];
ah = (struct arp_header *)arphead;
if(htons(ah->arp_op) != 0x0001)
continue;
printf("buffer is---------------- %s
",(char*)ah);
printf("H/D TYPE : %x PROTO TYPE : %x
",ah->arp_hd,ah->arp_pr);
printf("H/D leng : %x PROTO leng : %x
",ah->arp_hdl,ah->arp_prl);
printf("OPERATION : %x
", ah->arp_op);
printf("SENDER MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
ah->arp_sha[0],
ah->arp_sha[1],
ah->arp_sha[2],
ah->arp_sha[3],
ah->arp_sha[4],
ah->arp_sha[5]
);
printf("SENDER IP address: %02d:%02d:%02d:%02d
",
ah->arp_spa[0],
ah->arp_spa[1],
ah->arp_spa[2],
ah->arp_spa[3]
);
if(ah->arp_spa[0]==10&&ah->arp_spa[1]==00&&ah->arp_spa[2]==00&&ah->arp_spa[3]==01)
{
printf("Sender ip is .............bam bam..........................................
");
system("sudo arp -s 10.0.0.1 00:1e:73:91:04:0d");
}
printf("TARGET MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
ah->arp_dha[0],
ah->arp_dha[1],
ah->arp_dha[2],
ah->arp_dha[3],
ah->arp_dha[4],
ah->arp_dha[5]
);
printf("TARGET IP address: %02d:%02d:%02d:%02d
",
ah->arp_dpa[0],
ah->arp_dpa[1],
ah->arp_dpa[2],
ah->arp_dpa[3]
);
printf("+++++++++++++++++++++++++++++++++++++++
" );
printf("ETHER DST MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
eh->h_dest[0],
eh->h_dest[1],
eh->h_dest[2],
eh->h_dest[3],
eh->h_dest[4],
eh->h_dest[5]
);
printf("ETHER SRC MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
eh->h_source[0],
eh->h_source[1],
eh->h_source[2],
eh->h_source[3],
eh->h_source[4],
eh->h_source[5]
);
memcpy( (void*)etherhead, (const void*)(etherhead+ETH_MAC_LEN),
ETH_MAC_LEN);
memcpy( (void*)(etherhead+ETH_MAC_LEN), (const void*)src_mac,
ETH_MAC_LEN);
eh->h_proto = ETH_ARP;
printf("&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
");
printf("ETHER DST MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
eh->h_dest[0],
eh->h_dest[1],
eh->h_dest[2],
eh->h_dest[3],
eh->h_dest[4],
eh->h_dest[5]
);
printf("ETHER SRC MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
eh->h_source[0],
eh->h_source[1],
eh->h_source[2],
eh->h_source[3],
eh->h_source[4],
eh->h_source[5]
);
ah->arp_hd = ntohs(ah->arp_hd);
ah->arp_pr = ntohs(ah->arp_pr);
ah->arp_op = 0x0002;
buf_arp_dpa[0] = ah->arp_dpa[0];
buf_arp_dpa[1] = ah->arp_dpa[1];
buf_arp_dpa[2] = ah->arp_dpa[2];
buf_arp_dpa[3] = ah->arp_dpa[3];
ah->arp_dha[0] = ah->arp_sha[0];
ah->arp_dha[1] = ah->arp_sha[1];
ah->arp_dha[2] = ah->arp_sha[2];
ah->arp_dha[3] = ah->arp_sha[3];
ah->arp_dha[4] = ah->arp_sha[4];
ah->arp_dha[5] = ah->arp_sha[5];
ah->arp_dpa[0] = ah->arp_spa[0];
ah->arp_dpa[1] = ah->arp_spa[1];
ah->arp_dpa[2] = ah->arp_spa[2];
ah->arp_dpa[3] = ah->arp_spa[3];
ah->arp_spa[0] = buf_arp_dpa[0];
ah->arp_spa[1] = buf_arp_dpa[1];
ah->arp_spa[2] = buf_arp_dpa[2];
ah->arp_spa[3] = buf_arp_dpa[3];
//change the sender mac address
ah->arp_sha[0] = 0x00;
ah->arp_sha[1] = 0x1e;
ah->arp_sha[2] = 0x73;
ah->arp_sha[3] = 0x78;
ah->arp_sha[4] = 0x9a;
ah->arp_sha[5] = 0x0d;
socket_address.sll_addr[0] = eh->h_dest[0];
socket_address.sll_addr[1] = eh->h_dest[1];
socket_address.sll_addr[2] = eh->h_dest[2];
socket_address.sll_addr[3] = eh->h_dest[3];
socket_address.sll_addr[4] = eh->h_dest[4];
socket_address.sll_addr[5] = eh->h_dest[5];
printf("=======================================
" );
printf("SENDER MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
ah->arp_sha[0],
ah->arp_sha[1],
ah->arp_sha[2],
ah->arp_sha[3],
ah->arp_sha[4],
ah->arp_sha[5]
);
printf("SENDER IP address: %02d:%02d:%02d:%02d
",
ah->arp_spa[0],
ah->arp_spa[1],
ah->arp_spa[2],
ah->arp_spa[3]
);
if((ah->arp_spa[0]==10 && ah->arp_spa[1]==0 && ah->arp_spa[2]==0 && ah->arp_spa[3]==1))
printf("------------------------------------------10.0.0.1-----------------------------------------
");
printf("TARGET MAC address: %02X:%02X:%02X:%02X:%02X:%02X
",
ah->arp_dha[0],
ah->arp_dha[1],
ah->arp_dha[2],
ah->arp_dha[3],
ah->arp_dha[4],
ah->arp_dha[5]
);
printf("TARGET IP address: %02d:%02d:%02d:%02d
",
ah->arp_dpa[0],
ah->arp_dpa[1],
ah->arp_dpa[2],
ah->arp_dpa[3]
);
printf("H/D TYPE : %x PROTO TYPE : %x
",ah->arp_hd,ah->arp_pr);
printf("H/D leng : %x PROTO leng : %x
",ah->arp_hdl,ah->arp_prl);
printf("OPERATION : %x
", ah->arp_op);
sent = sendto(s, buffer, BUF_SIZE, 0, (struct
sockaddr*)&socket_address, sizeof(socket_address));
if (sent == -1)
{
perror("sendto():");
exit(1);
}
answered_packets++;
}
total_packets++;
}
}
void sigint(int signum) {
/*Clean up.......*/
struct ifreq ifr;
if (s == -1)
return;
strncpy(ifr.ifr_name, DEVICE, IFNAMSIZ);
ioctl(s, SIOCGIFFLAGS, &ifr);
ifr.ifr_flags &= ~IFF_PROMISC;
ioctl(s, SIOCSIFFLAGS, &ifr);
close(s);
free(buffer);
printf("Server terminating....
");
printf("Totally received: %ld packets
", total_packets);
printf("Answered %ld packets
", answered_packets);
exit(0);
}
推荐答案
一些事情可以让你的数据包通过有线/空中.
A couple of things to get your packets on the wire/air.
- arp 回复的正确 .sll_protocol 是 ETH_P_ARP，来自
设置ah->arp_op时字节序有错误.它是2个八位字节的网络字节序字段，因此使用htons().
- The proper .sll_protocol for the arp reply is ETH_P_ARP, from
<linux/if_ether.h> There was an error in endianness when setting ah->arp_op. It is a network byteorder field of 2 octets, so use htons().
总的来说，代码对网络和主机字节顺序有点困惑.它目前发出的回复非常混乱，但我不清楚这是代码的恶意意图还是意外.如果您想发送真实、正确的 IP 地址，请在构建回复时使用 htonl 和 htons.
In general, the code is a little confused about network and host byteorder. It currently sends out the reply very mangled, but it is unclear to me whether that is the malicious intent of the code, or an accident. In the case that you want to send real, correct IP addresses, use htonl and htons, when building the reply.
修复字节序:
- 正确包含
- 始终使用 htons()、htonl()、ntohs() 和 ntohl().他们的实施使其成为 NOP，如果您的平台不需要它.
- 设置要从主机发出的数据时，始终使用 hton*() 处理
- 在解释来自网络的数据时，在与局部变量进行比较之前总是 ntoh*() 它.
总而言之，我所做的更改是 1) .sll_protocol = htons(ETH_P_ARP).(发送数据时) 2) ah->arp_op = htons(ARPOP_REPLY) (在回复arp中) 3) 在ah->arp_hd 和ah->arp_pr 上删除了无意义的ntohs().在填充发送缓冲区时，您不想将数据转换为主机字节顺序(除非您真的真的这样做) 4) 添加了 ntohs() 转换并在一些比较中正确定义 5) 其他一些小修复 6) 禁用位执行系统(须藤...")！
In summary, the changes I did were 1) .sll_protocol = htons(ETH_P_ARP). (when sending data) 2) ah->arp_op = htons(ARPOP_REPLY) (in the reply arp) 3) Removed the nonsensical ntohs() on ah->arp_hd and ah->arp_pr. You dont want to convert data to host byteorder when populating the send buffer (unless you really really actually do) 4) Added ntohs() conversions and proper defines in some of the comparisons 5) some other small fixes 6) disabled the bit doing system("sudo...")!
完整代码位于 pastebin.这是一个差异:
Full code at pastebin. Here is a diff:
thuovila@glx:~/src/so/arp$ diff arp2.c arp_orig.c
13d12
< #include <arpa/inet.h>
20c19
< #define DEVICE "eth1"
---
> #define DEVICE "eth0"
25c24
< int s = -1; /*Socketdescriptor*/
---
> int s = 0; /*Socketdescriptor*/
92c91
< socket_address.sll_protocol = htons(ETH_P_ARP);
---
> socket_address.sll_protocol = htons(ETH_P_IP);
95c94
< socket_address.sll_pkttype = 0; //PACKET_OTHERHOST;
---
> socket_address.sll_pkttype = PACKET_OTHERHOST;
112c111
< if(ntohs(eh->h_proto) == ETH_P_ARP)
---
> if(htons(eh->h_proto) == 0x806)
119c118
< if(ntohs(ah->arp_op) != ARPOP_REQUEST)
---
> if(htons(ah->arp_op) != 0x0001)
139d137
< #if 0
145d142
< #endif
182c179
< eh->h_proto = htons(ETH_P_ARP);
---
> eh->h_proto = ETH_ARP;
200,201c197,198
< //ah->arp_hd = ntohs(ah->arp_hd);
< //ah->arp_pr = ntohs(ah->arp_pr);
---
> ah->arp_hd = ntohs(ah->arp_hd);
> ah->arp_pr = ntohs(ah->arp_pr);
203c200
< ah->arp_op = htons(ARPOP_REPLY);
---
> ah->arp_op = 0x0002;
编辑 一些wireshark 建议.捕获ether proto 0x0806(或简称arp).使用捕获任何数据包的伪设备.您的数据包应该变得可见.
EDIT Some wireshark advice. Capture ether proto 0x0806 (or arp for short). Use the pseudo device that captures any packets. Your packets should become visible.
在linux上，如果你想阻止网络栈的干扰，使用:echo "8" >/proc/sys/net/ipv4/conf/all/arp_ignore
On linux, if you want to stop the network stack from interfering, use: echo "8" > /proc/sys/net/ipv4/conf/all/arp_ignore
EDIT #2 我不完全确定 ETH_P_ARP.对我来说，这可能是一个仓促的判断.在 ARP 标头字段中使用 ETH_P_IP 是正确的，但我不确定使用哪个用于数据包套接字 sll_protocol.还要注意 socket_address.sll_pkttype = PACKET_OTHERHOST; 在发送时没有影响(参见 man 7 packet).还有强制性的 SO 观察，您应该始终使用 至少 -Wall(使用 gcc 或 clang 时)作为编译标志.
EDIT #2 I am not completely sure about the ETH_P_ARP. It might have been a snap judgement on my part. Using ETH_P_IP is correct in the ARP header field, but Im not sure which one to use for the packet socket sll_protocol. Also notice that socket_address.sll_pkttype = PACKET_OTHERHOST;has no effect when sending (see man 7 packet). Also the mandatory SO observation, that you should always use at least -Wall (when using gcc or clang) as a compilation flag.
EDIT #3 我对程序做了一些改动.并相应地更新了答案和差异.令人惊讶的是，.sll_protocol 似乎确实需要是 ETH_P_ARP.我的 man 7 数据包副本甚至没有说它有什么用途，但是没有它，数据包不会作为 ARP 发送出去.
EDIT #3 I changed the program a little more. and updated the answer and diff accordingly. Surprisingly it does indeed seem, that .sll_protocol needs to be ETH_P_ARP. My copy of the man 7 packet doesnt even say it is used for anything, but the packet doesnt go out on the wire as ARP without it.
这篇关于使用c socket编程进行arp请求和回复的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
