busybox/libbb/create_icmp_socket.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* create raw socket for icmp protocol test permision
* and drop root privilegies if running setuid
*
*/
#include <sys/types.h>
#include <netdb.h>
#include <sys/socket.h>
#include <errno.h>
#include <unistd.h>
#include "libbb.h"
int create_icmp_socket(void)
{
struct protoent *proto;
int sock;
proto = getprotobyname("icmp");
/* if getprotobyname failed, just silently force
* proto->p_proto to have the correct value for "icmp" */
if ((sock = socket(AF_INET, SOCK_RAW,
(proto ? proto->p_proto : 1))) < 0) { /* 1 == ICMP */
if (errno == EPERM)
error_msg_and_die("permission denied. (are you root?)");
else
perror_msg_and_die(can_not_create_raw_socket);
}
/* drop root privs if running setuid */
setuid(getuid());
return sock;
}