ping3.c

e75179f41c5d50dd62c60f572182b8178ed03e94 · 2.7 KB · 110 lines raw

1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <unistd.h>
4 #include <sys/types.h>
5 #include <sys/socket.h>
6 #include <netdb.h>
7 #include <netinet/in.h>
8 #include <netinet/in_systm.h>
9 #include <netinet/ip.h>
10 #include <netinet/ip_icmp.h>
11 #include <string.h>
12 #include <arpa/inet.h>
13 #include <sys/select.h>
14
15 unsigned short cksum(unsigned short *addr, int len);
16
17 int main(int argc, char *argv[]) {
18 int sock;
19 char send_buf[400], src_ip[15], dst_ip[15], src_name[256];
20 struct ip *ip = (struct ip *)send_buf;
21 struct icmp *icmp = (struct icmp *)(ip + 1);
22 struct hostent *src_hp, *dst_hp;
23 struct sockaddr_in src, dst;
24 int on = 1;
25 memset(send_buf, 0, sizeof(send_buf));
26
27 if (argc < 2) {
28 printf("Need arg. I\n");
29 exit(EXIT_FAILURE);
30 }
31
32 /**if (getuid() == 0) {
33 fprintf(stderr, "Need to elevate\n");
34 exit(EXIT_FAILURE);
35 } **/
36
37 gethostname(src_name, sizeof(src_name));
38 printf("%s\n", src_name);
39 src_hp = gethostbyname(src_name);
40 ip->ip_src = (*(struct in_addr *)src_hp->h_addr_list[0]);
41
42 dst_hp = gethostbyname(argv[1]);
43 ip->ip_dst = (*(struct in_addr *)dst_hp->h_addr);
44 dst.sin_addr = (*(struct in_addr *)dst_hp->h_addr);
45
46 sprintf(src_ip, "%s", inet_ntoa(ip->ip_src));
47 sprintf(dst_ip, "%s", inet_ntoa(ip->ip_dst));
48 printf("Src: %s -- Dst: %s\n", src_ip, dst_ip);
49
50 // Create socket
51 sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
52
53 setsockopt(sock, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on));
54
55 // IP Structure
56 ip->ip_v = 4;
57 ip->ip_hl = 5;
58 ip->ip_tos = 0;
59 ip->ip_len = htons(sizeof(send_buf));
60 ip->ip_id = htons(321);
61 ip->ip_off = htons(0);
62 ip->ip_ttl = 255;
63 ip->ip_p = IPPROTO_ICMP;
64 ip->ip_sum = 0;
65
66 // ICMP Structure
67 icmp->icmp_type = 2;
68 icmp->icmp_code = 0;
69
70 dst.sin_family = AF_INET;
71
72 ip->ip_sum = cksum((unsigned short *)send_buf, ip->ip_hl);
73 icmp->icmp_cksum = cksum((unsigned short *)icmp, sizeof(send_buf) - sizeof(struct icmp));
74
75 int dst_addr_len = sizeof(dst);
76 int bytes_sent;
77
78 if((bytes_sent = sendto(sock, send_buf, sizeof(send_buf), 0, (struct sockaddr *)&dst, dst_addr_len)) < 0) {
79 perror("send err");
80 fflush(stdout);
81 }
82 else {
83 printf("Sent %d bytes\n", bytes_sent);
84 }
85
86
87 }
88
89 unsigned short cksum(unsigned short *addr, int len) {
90 int nleft = len;
91 int sum = 0;
92 unsigned short *w = addr;
93 unsigned short answer = 0;
94
95 while (nleft > 1) {
96 sum += *w++;
97 nleft -= 2;
98 }
99
100 if (nleft == 1) {
101 *(unsigned char *)(&answer) = *(unsigned char *)w;
102 sum += answer;
103 }
104
105 sum = (sum >> 16) + (sum & 0xffff);
106 sum += (sum >> 16);
107 answer = ~sum;
108
109 return answer;
110 }