servname.c

来自「一个网络流量分析的完整的程序」· C语言 代码 · 共 47 行

/***

servname.c	- lookup module for TCP and UDP service names based on
		  port numbers

Copyright (c) Gerard Paul Java 1998

This software is open source; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License in the included COPYING file for
details.

***/

#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <netinet/in.h>

void servlook(int servnames, unsigned int port, unsigned int protocol,
	      char *target, int maxlen)
{
    static struct servent *sve;

    bzero(target, maxlen + 1);

    if (servnames) {
	if (protocol == IPPROTO_TCP)
	    sve = getservbyport(port, "tcp");
	else
	    sve = getservbyport(port, "udp");

	if (sve != NULL) {
	    strncpy(target, sve->s_name, maxlen);
	} else {
	    sprintf(target, "%u", ntohs(port));
	}
    } else {
	sprintf(target, "%u", ntohs(port));
    }
}