perl - 如何在 perl 中设置传出数据包的 TTL？

Question

我如何设置 Time-To-Live perl 中的套接字选项？setsockopt()的参数是什么，或者有更好的方法吗？

Answer 1

以下适用于我，在 Linux 上:
IPv4

use Socket;
...
socket (SOCKET, ...) or die "Can't create socket: $!";
my $ip = getprotobyname ('ip'); # just in case it ever changes ;-)
my $opname = IP_TTL;
my $opval = int $ttl; # if $ttl is a string, convert to int
setsockopt (SOCKET, $ip, $opname, $opval) or warn "setsockopt failed: $!";

IPv6

use Socket("SOCK_STREAM", "IPV6_UNICAST_HOPS");
...
my $ipv6 = getprotobyname('ipv6');
my $opname = IPV6_UNICAST_HOPS; 
my $opval = int $ttl;
setsockopt (SOCKET,$ipv6,$opname,$opval) or warn "setsockopt failed: $!";