103 lines
2.6 KiB
C
103 lines
2.6 KiB
C
#include "ft_ping.h"
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uint16_t calculate_checksum(uint16_t *data, int len)
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{
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uint32_t checksum = 0;
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while (len > 1)
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{
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checksum += *data++;
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len -= 2;
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}
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if (len == 1)
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checksum += *(uint8_t *)data;
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while (checksum >> 16)
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checksum = (checksum & 0xFFFF) + (checksum >> 16);
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printf("checksum is : %X\n", (uint16_t)~checksum);
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return (~checksum);
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}
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int ft_ping(int sock, int *seq, struct sockaddr_in src, struct sockaddr_in dst)
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{
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unsigned char data[2048];
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unsigned char data2[2048];
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int len;
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struct icmp_header *icmp_hdr = (struct icmp_header *)data;
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memset(data, 0, sizeof(data));
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memset(data2, 0, sizeof(data2));
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sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
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if (sock < 0)
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{
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fprintf(stderr, "ERROR : socket() failed\n");
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return (0);
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}
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if (getsockname(sock, (struct sockaddr *)&src, &len) < 0)
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{
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fprintf(stderr, "ERROR : getsockname() failed\n");
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return (0);
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}
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dst.sin_family = AF_INET;
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memset(icmp_hdr, 0, sizeof(icmp_hdr));
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icmp_hdr->type = ICMP_ECHO;
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icmp_hdr->code = 0;
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icmp_hdr->checksum = 0;
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icmp_hdr->id = getpid();
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icmp_hdr->seq = *seq++;
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icmp_hdr->checksum = calculate_checksum((uint16_t *)icmp_hdr, sizeof(icmp_hdr));
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if (sendto(sock, data, sizeof(data), 0, (struct sockaddr *)&dst, sizeof(dst)) == -1)
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{
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fprintf(stderr, "ERROR : sendto() failed\n");
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return (0);
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}
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if (recvfrom(sock, data2, sizeof(data2), 0, (struct sockaddr *)&src, &len) == -1)
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{
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fprintf(stderr, "ERROR : recvfrom() failed\n");
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return (0);
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}
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struct icmp_header *icmp_recv_hdr = (struct icmp_header *)(data2 + 20);
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for (int i = 0; data[i]; i++)
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printf("%c", data[i]);
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for (int i = 0; data2[i]; i++)
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printf("%c", data2[i]);
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if (icmp_recv_hdr->type != ICMP_ECHOREPLY || icmp_recv_hdr->code != 0)
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{
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printf("%d %d\n", icmp_recv_hdr->type, icmp_recv_hdr->code);
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fprintf(stderr, "ERROR : invalid packet received (code)\n");
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return (0);
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}
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if (icmp_recv_hdr->id != icmp_hdr->id)
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{
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fprintf(stderr, "ERROR : invalid packet received (id is not matching)\n");
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return (0);
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}
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if (icmp_recv_hdr->seq != icmp_hdr->seq)
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{
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fprintf(stderr, "ERROR : invalid packet received (sequence is not matching)\n");
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return (0);
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}
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printf("success");
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close(sock);
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return (1);
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}
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int main(int argc, char **argv)
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{
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int sock;
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struct sockaddr_in src, dst;
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int seq = 1;
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src.sin_family = AF_INET;
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if (argc != 2 || argv[1] == NULL || argv[1][0] == 0)
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{
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fprintf(stderr, "ERROR : usage : ping {-v?} [ADRESS]\n");
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return (0);
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}
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if (gethostbyname(argv[1]) == NULL && inet_aton(argv[1], (struct in_addr *)&dst.sin_addr.s_addr) == 0)
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{
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fprintf(stderr, "ERROR : %s is an invalid adress\n", argv[1]);
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return (0);
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}
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return (ft_ping(sock, &seq, src, dst));
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} |