010 使用netmap API接管网卡，接收数据包，回应ARP请求

1 /*
2 ============================================================================
3 Name        : send_packet_01.c
4 Author      : huh
5 Version     :
6 Copyright   : huh's copyright notice
7 Description : Hello World in C, Ansi-style
8 ============================================================================
9  */
10 
11 #include <sys/types.h>
12 #include <sys/socket.h>
13 #include <stdio.h>
14 #include <netinet/in.h>
15 #include <arpa/inet.h>
16 #include <unistd.h>
17 #include <stdlib.h>
18 #include <string.h>
19 #include <netinet/ip_icmp.h>
20 #include <netinet/udp.h>
21 
22 #define MAXLINE 1024*10
23 
24 intmain()
25 {
26     intsockfd;
27     structsockaddr_in server_addr;
28     //创建原始套接字
29     sockfd = socket(AF_INET, SOCK_DGRAM, 0);
30     //创建套接字地址
31     bzero(&server_addr,sizeof(server_addr));
32     server_addr.sin_family =AF_INET;
33     server_addr.sin_port = htons(8686);
34     server_addr.sin_addr.s_addr = inet_addr("192.168.11.134");
35     char sendline[10]="adcde";
36     while(1)
37 {
38         sendto(sockfd, sendline, strlen(sendline), 0, (struct sockaddr *)&server_addr, sizeof(server_addr));
39         printf("%s
",sendline);
40         sleep(1);
41 }
42     return 0;
43 }

1 /*
2 ============================================================================
3 Name        : recv_pkt.c
4 Author      : huh
5 Version     :
6 Copyright   : huh's copyright notice
7 Description : Hello World in C, Ansi-style
8 ============================================================================
9  */
10 
11 #include <stdio.h>
12 #include <unistd.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <ifaddrs.h>
16 #include <net/ethernet.h>
17 #include <netinet/in.h>
18 #include <netinet/ip.h>
19 #include <netinet/udp.h>
20 #include <netinet/ether.h>
21 #include <netinet/if_ether.h>
22 
23 #include <unistd.h>    //sysconf()
24 #include <sys/poll.h>
25 #include <arpa/inet.h>
26 
27 #include "netmap_user.h" /*来源与netmap */
28 #pragma pack(1) /* 设置结构体的边界对齐为1个字节 */
29 
30 struct udp_pkt  /*普通的完整udp数据包 */
31 {
32     struct ether_header eh;      /*以太网头部,14字节,<net/ethernet.h>头文件中 */
33     struct iphdr ip;              /*ip部分,20字节,<netinet/ip.h>头文件中 */
34     struct udphdr udp;             /*udp部分,8字节,<netinet/udp.h>头文件中 */
35     uint8_t body[20];            /*数据部分,暂时分配20字节 */
36 };
37 
38 struct arp_pkt /*完整arp数据包(以太网首部 + ARP字段) */
39 {
40     struct ether_header eh;      /*以太网头部,14字节,<net/ethernet.h>头文件中 */
41     struct ether_arp arp;          /*ARP字段  ,28字节,<netinet/if_ether.h>头文件中 */
42 };
43 
44 void Print_mac_addr(const unsigned char *str) /*打印mac地址 */
45 {
46     inti;
47     for (i = 0; i < 5; i++)
48         printf("%02x:", str[i]);
49     printf("%02x", str[i]);
50 }
51 
52 void Print_ip_addr(const unsigned char *str) /*打印ip地址 */
53 {
54     inti;
55     for (i = 0; i < 3; i++)
56         printf("%d.", str[i]);
57     printf("%d", str[i]);
58 }
59 
60 void Print_arp_pkt(struct arp_pkt* arp_pkt) /*打印完整的arp数据包的内容 */
61 {
62     Print_mac_addr(arp_pkt->eh.ether_dhost), printf(" "); /*以太网目的地址 */
63     Print_mac_addr(arp_pkt->eh.ether_shost), printf(" "); /*以太网源地址 */
64     printf("0x%04x ", ntohs(arp_pkt->eh.ether_type));     /*帧类型:0x0806 */
65     printf("  ");
66     printf("%d ",     ntohs(arp_pkt->arp.ea_hdr.ar_hrd));         /*硬件类型:1 */
67     printf("0x%04x ", ntohs(arp_pkt->arp.ea_hdr.ar_pro));         /*协议类型:0x0800 */
68     printf("%d ",arp_pkt->arp.ea_hdr.ar_hln);      /*硬件地址:6 */
69     printf("%d ",arp_pkt->arp.ea_hdr.ar_pln);      /*协议地址长度:4 */
70     printf("%d ",     ntohs(arp_pkt->arp.ea_hdr.ar_op));  /*操作字段:ARP请求值为1,ARP应答值为2 */
71     printf("  ");
72     Print_mac_addr(arp_pkt->arp.arp_sha), printf(" ");    /*发送端以太网地址*/
73     Print_ip_addr(arp_pkt->arp.arp_spa), printf(" ");     /*发送端IP地址 */
74     Print_mac_addr(arp_pkt->arp.arp_tha), printf(" ");    /*目的以太网地址 */
75     Print_ip_addr(arp_pkt->arp.arp_tpa), printf(" ");     /*目的IP地址 */
76     printf("");
77 }
78 
79 /*
80 * 根据ARP request生成ARP reply的packet
81 * hmac为本机mac地址
82  */
83 void Init_echo_pkt(struct arp_pkt *arp, struct arp_pkt *arp_rt, char *hmac)
84 {
85     bcopy(arp->eh.ether_shost,     arp_rt->eh.ether_dhost, 6);   /*填入目的地址 */
86     bcopy(ether_aton(hmac),     arp_rt->eh.ether_shost, 6);   /*hmac为本机mac地址 */
87     arp_rt->eh.ether_type =     arp->eh.ether_type;           /*以太网帧类型 */
88 ;
89     arp_rt->arp.ea_hdr.ar_hrd = arp->arp.ea_hdr.ar_hrd;
90     arp_rt->arp.ea_hdr.ar_pro = arp->arp.ea_hdr.ar_pro;
91     arp_rt->arp.ea_hdr.ar_hln = 6;
92     arp_rt->arp.ea_hdr.ar_pln = 4;
93     arp_rt->arp.ea_hdr.ar_op = htons(2);                     /*ARP应答 */
94 ;
95     bcopy(ether_aton(hmac), &arp_rt->arp.arp_sha, 6);        /*发送端以太网地址*/
96     bcopy(arp->arp.arp_tpa, &arp_rt->arp.arp_spa, 4);        /*发送端IP地址 */
97     bcopy(arp->arp.arp_sha, &arp_rt->arp.arp_tha, 6);        /*目的以太网地址 */
98     bcopy(arp->arp.arp_spa, &arp_rt->arp.arp_tpa, 4);        /*目的IP地址 */
99 }
100 
101 intmain()
102 {
103     struct ether_header *eh;
104     structnm_pkthdr h;
105     struct nm_desc *nmr;
106     nmr = nm_open("netmap:eth0", NULL, 0, NULL);  /*打开netmap对应的文件描述符,并做了相关初始化操作！ */
107     structpollfd pfd;
108     pfd.fd = nmr->fd;
109     pfd.events =POLLIN;
110     u_char *str;
111     printf("ready!!!
");
112     while (1)
113 {
114         poll(&pfd, 1, -1); /*使用poll来监听是否有事件到来 */
115         if (pfd.revents &POLLIN)
116 {
117             str = nm_nextpkt(nmr, &h);                     /*接收到来的数据包 */
118             eh = (struct ether_header *) str;
119             if (ntohs(eh->ether_type) == 0x0800)                     /*接受的是普通IP包 */
120 {
121                 struct udp_pkt *p = (struct udp_pkt *)str;
122                 if(p->ip.protocol == IPPROTO_UDP)   /*如果是udp协议的数据包*/
123                     printf("udp:%s
", p->body);
124                 else
125                     printf("其它IP协议包!
");
126 }
127             else if (ntohs(eh->ether_type) == 0x0806)                  /*接受的是ARP包 */
128 {
129                 structarp_pkt arp_rt;
130                 struct arp_pkt *arp = (struct arp_pkt *)str;
131                 if( *(uint32_t *)arp->arp.arp_tpa == inet_addr("192.168.11.134") ) /*如果请求的IP是本机IP地址(两边都是网络字节序)*/
132 {
133                     printf("ARP请求:");
134 Print_arp_pkt(arp);
135                     Init_echo_pkt(arp, &arp_rt, "00:0C:29:E4:D6:2A");     /*根据收到的ARP请求生成ARP应答数据包*/
136                     printf("ARP应答:");
137                     Print_arp_pkt(&arp_rt);
138                     nm_inject(nmr, &arp_rt, sizeof(struct arp_pkt));      /*发送ARP应答包 */
139 }
140                 else
141                     printf("其它主机的ARP请求！
");
142 }
143 }
144 }
145 nm_close(nmr);
146     return 0;
147 }