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/*
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/String.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/ElapsedTimer.h>
#include <arpa/inet.h>
#include <errno.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/ip_icmp.h>
#include <serenity.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
int main(int argc, char** argv)
{
if (pledge("stdio id inet unix", nullptr) < 0) {
perror("pledge");
return 1;
}
const char* host_name;
int max_hops = 30;
int max_retries = 3;
int echo_timeout = 5;
Core::ArgsParser args_parser;
args_parser.add_positional_argument(host_name, "destination", "destination", Core::ArgsParser::Required::Yes);
args_parser.add_option(max_hops, "use at most <hops> to the destination", "max-hops", 'h', "hops");
args_parser.add_option(max_retries, "retry TTL at most <tries> times", "max-retries", 'r', "tries");
args_parser.add_option(echo_timeout, "wait at most <seconds> for a response", "timeout", 't', "seconds");
args_parser.parse(argc, argv);
if (max_hops < 1 || max_hops > 255) {
warnln("Invalid maximum hops amount");
return 1;
}
if (max_retries < 1) {
warnln("Invalid maximum retries amount");
return 1;
}
auto* hostent = gethostbyname(host_name);
if (!hostent) {
warnln("Lookup failed for '{}'", host_name);
return 1;
}
sockaddr_in host_address {};
memset(&host_address, 0, sizeof(host_address));
host_address.sin_family = AF_INET;
host_address.sin_port = 44444;
host_address.sin_addr.s_addr = *(const in_addr_t*)hostent->h_addr_list[0];
int fd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if (fd < 0) {
perror("socket");
return 1;
}
if (setgid(getgid()) || setuid(getuid())) {
warnln("Failed to drop privileges");
return 1;
}
if (pledge("stdio inet unix", nullptr) < 0) {
perror("pledge");
return 1;
}
timeval timeout { echo_timeout, 0 };
if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) < 0) {
perror("setsockopt");
return 1;
}
struct icmp_request {
struct icmphdr header;
char msg[64 - sizeof(struct icmphdr)];
};
struct icmp_response {
u8 ip_header[20];
struct icmphdr header;
char msg[64 - sizeof(struct icmphdr)];
};
// 1: reached target
// 0: got ttl exhausted response
// -1: error or no response
auto try_reach_host = [&](int ttl) -> int {
Core::ElapsedTimer m_timer { true };
for (auto i = 0; i < max_retries; i++) {
icmp_request request {};
request.header = { ICMP_ECHO, 0, 0, { { 0, 0 } } };
bool fits = String::number(ttl).copy_characters_to_buffer(request.msg, sizeof(request.msg));
VERIFY(fits);
request.header.checksum = internet_checksum(&request, sizeof(request));
m_timer.start();
if (sendto(fd, &request, sizeof(request), 0, (sockaddr*)&host_address, sizeof(host_address)) < 0)
return -1;
icmp_response response {};
sockaddr_in peer_address {};
memset(&peer_address, 0, sizeof(peer_address));
size_t peer_address_size = sizeof(peer_address);
int result = recvfrom(fd, &response, sizeof(response), 0, (sockaddr*)&peer_address, (socklen_t*)&peer_address_size);
if (result < 0) {
if (errno == EAGAIN)
return -1;
continue;
}
auto response_time = m_timer.elapsed();
if (response.header.type != ICMP_ECHOREPLY && response.header.type != ICMP_TIME_EXCEEDED)
continue;
auto* peer = gethostbyaddr(&peer_address.sin_addr, sizeof(peer_address.sin_addr), AF_INET);
String peer_name;
if (peer) {
peer_name = peer->h_name;
} else {
char addr_buf[INET_ADDRSTRLEN];
peer_name = inet_ntop(AF_INET, &peer_address.sin_addr, addr_buf, sizeof(addr_buf));
}
outln("{:2}: {:50} {:4}ms", ttl, peer_name, response_time);
if (response.header.type == ICMP_TIME_EXCEEDED)
return 0;
if (response.header.type == ICMP_ECHOREPLY)
return 1;
}
return -1;
};
for (auto ttl = 1; ttl <= max_hops; ttl++) {
if (setsockopt(fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) < 0) {
perror("setsockopt");
return 1;
}
int result = try_reach_host(ttl);
if (result < 0) {
outln("{:2}: no reply", ttl);
} else if (result == 1) {
outln(" Hops: {}", ttl);
return 0;
}
}
outln(" Too many hops: {}", max_hops);
return 0;
}
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