Files
ft_ping/srcs/icmp.c
2025-05-22 23:30:01 +02:00

109 lines
2.9 KiB
C

/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* icmp.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: tomoron <tomoron@student.42angouleme.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2025/04/24 22:49:22 by tomoron #+# #+# */
/* Updated: 2025/05/22 22:19:36 by tomoron ### ########.fr */
/* */
/* ************************************************************************** */
#include "includes/ft_ping.h"
static void set_packet_data(uint8_t *packet_data)
{
int i;
i = 0;
while(i < PACKET_DATA_LENGTH)
{
packet_data[i] = i;
i++;
}
}
uint16_t calc_checksum(void *ptr, size_t len)
{
uint32_t res;
uint16_t *data;
data = ptr;
res = 0;
while (len > 1)
{
res += *data;
data++;
len -= 2;
}
if (len)
res += *(uint8_t *)data;
while (res >> 16) {
res = (res & 0xFFFF) + (res >> 16);
}
return(~res);
}
t_icmp_echo prepare_icmp_echo(uint16_t sequence, uint16_t identifier)
{
t_icmp_echo packet;
packet.type = 8;
packet.code = 0;
packet.identifier = htons(identifier);
packet.sequence = htons(sequence);
set_packet_data(packet.data);
gettimeofday(&packet.time, 0);
packet.checksum = 0;
packet.checksum = calc_checksum(&packet, sizeof(t_icmp_echo));
return(packet);
}
t_waitlist *send_icmp(t_settings *set, struct addrinfo *host, uint16_t *seq, struct timeval *last, t_stats *stats)
{
t_icmp_echo packet;
t_waitlist *ret;
if(timediff(last) < set->interval)
return (0);
packet = prepare_icmp_echo(*seq, set->id);
sendto(set->socket, &packet, sizeof(t_icmp_echo), 0, host->ai_addr, host->ai_addrlen);
gettimeofday(last, 0);
ret = malloc(sizeof(t_waitlist));
if(!ret)
return(0);
ret->time = *last;
ret->seq = *seq;
ret->next = 0;
stats->sent++;
gettimeofday(&set->last_send_time, 0);
(*seq)++;
return(ret);
}
void receive_icmp(t_settings *set, struct addrinfo *info, t_waitlist **wl, t_stats *stats)
{
size_t len;
t_icmp_ip_reply res;
uint16_t checksum;
len = recvfrom(set->socket, &res, sizeof(t_icmp_ip_reply), 0, info->ai_addr, &info->ai_addrlen);
if(len < sizeof(t_icmp_ip_reply))
return;
if(len == (size_t)-1 )
return;
if(res.icmp.type != 0 && res.icmp.identifier != set->id)
return ;
checksum = res.icmp.checksum;
res.icmp.checksum = 0;
if(calc_checksum(&res.icmp, sizeof(t_icmp_echo)) != checksum)
return ;
res.icmp.sequence = htons(res.icmp.sequence);
waitlist_remove(wl, res.icmp.sequence, set, stats, res.header.ttl);
}