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made more robust and commented my code.

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This commit is contained in:
John Beppu 2000-01-30 09:47:16 +00:00
parent b332e779e6
commit 50bc101b7d
2 changed files with 114 additions and 74 deletions
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94
networking/nslookup.c
View File

@ -32,14 +32,24 @@
#include <sys/types.h> #include <sys/types.h>
#include <netinet/in.h> #include <netinet/in.h>
/*
| I'm only implementing non-interactive mode;
| I totally forgot nslookup even had an interactive mode.
|
| [ TODO ]
| + find out how to use non-default name servers
| + find out how the real nslookup gets the default name server
*/
static const char nslookup_usage[] = static const char nslookup_usage[] =
"only implementing non-interactive mode\n" "nslookup [HOST]\n\n"
"I totally forgot nslookup even had an interactive mode\n"
; ;
/* */ /* I have to see how the real nslookup does this.
* I could dig through /etc/resolv.conf, but is there a
* better (programatic) way?
*/
static void static void
server_fprint(FILE *dst) server_fprint(FILE *dst)
{ {
@ -67,7 +77,9 @@ addr_fprint(char *addr, FILE *dst)
return 0; return 0;
} }
/* */ /* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+
* into a uint32_t
*/
static uint32_t static uint32_t
str_to_addr(const char *addr) str_to_addr(const char *addr)
{ {
@ -86,59 +98,63 @@ str_to_addr(const char *addr)
return htonl(ip); return htonl(ip);
} }
/* */ /* takes the NULL-terminated array h_addr_list, and
* prints its contents appropriately
*/
static int static int
addr_list_fprint(char **h_addr_list, FILE *dst) addr_list_fprint(char **h_addr_list, FILE *dst)
{ {
int i; int i, j;
char *addr_string = (h_addr_list[1]) char *addr_string = (h_addr_list[1])
? "Addresses" ? "Addresses"
: "Address"; : "Address";
fprintf(dst, "%s: ", addr_string); fprintf(dst, "%s: ", addr_string);
for (i = 0; h_addr_list[i]; i++) { for (i = 0, j = 0; h_addr_list[i]; i++, j++) {
addr_fprint(h_addr_list[i], dst); addr_fprint(h_addr_list[i], dst);
if (h_addr_list[i+1]) {
fprintf(dst, ", "); /* real nslookup does this */
if (j == 4) {
if (h_addr_list[i+1]) {
fprintf(dst, "\n ");
}
j = 0;
} else {
if (h_addr_list[i+1]) {
fprintf(dst, ", ");
}
} }
} }
fprintf(dst,"\n"); fprintf(dst,"\n");
return 0; return 0;
} }
/* */ /* gethostbyaddr wrapper */
static struct hostent * static struct hostent *
lookup_by_name(const char *hostname) gethostbyaddr_wrapper(const char *address)
{ {
struct hostent *host; struct in_addr addr;
host = gethostbyname(hostname); addr.s_addr = str_to_addr(address);
return gethostbyaddr((char *) &addr, 4, AF_INET); /* IPv4 only for now */
}
/* print the results as nslookup would */
static struct hostent *
hostent_fprint(struct hostent *host, FILE *dst)
{
if (host) { if (host) {
fprintf(stdout, "Name: %s\n", host->h_name); fprintf(dst, "Name: %s\n", host->h_name);
addr_list_fprint(host->h_addr_list, stdout); addr_list_fprint(host->h_addr_list, dst);
} else { } else {
herror("crap"); fprintf(dst, "*** %s\n", hstrerror(h_errno));
} }
return host; return host;
} }
/* */
static struct hostent *
lookup_by_addr(const char *addr)
{
struct hostent *host;
host = gethostbyaddr(addr, 4, AF_INET); /* IPv4 only for now */ /* naive function to check whether char *s is an ip address */
if (host) {
fprintf(stdout, "Name: %s\n", host->h_name);
addr_list_fprint(host->h_addr_list, stdout);
} else {
herror("crap");
}
return host;
}
/* */
static int static int
is_ip_address(const char *s) is_ip_address(const char *s)
{ {
@ -153,16 +169,20 @@ is_ip_address(const char *s)
int int
nslookup_main(int argc, char **argv) nslookup_main(int argc, char **argv)
{ {
struct in_addr addr; struct hostent *host;
if (argc < 2) {
usage(nslookup_usage);
}
server_fprint(stdout); server_fprint(stdout);
if (is_ip_address(argv[1])) { if (is_ip_address(argv[1])) {
addr.s_addr = str_to_addr(argv[1]); host = gethostbyaddr_wrapper(argv[1]);
lookup_by_addr((char *) &addr);
} else { } else {
lookup_by_name(argv[1]); host = gethostbyname(argv[1]);
} }
hostent_fprint(host, stdout);
return 0; return 0;
} }
/* $Id: nslookup.c,v 1.1 2000/01/29 12:59:01 beppu Exp $ */ /* $Id: nslookup.c,v 1.2 2000/01/30 09:47:16 beppu Exp $ */

94
nslookup.c
View File

@ -32,14 +32,24 @@
#include <sys/types.h> #include <sys/types.h>
#include <netinet/in.h> #include <netinet/in.h>
/*
| I'm only implementing non-interactive mode;
| I totally forgot nslookup even had an interactive mode.
|
| [ TODO ]
| + find out how to use non-default name servers
| + find out how the real nslookup gets the default name server
*/
static const char nslookup_usage[] = static const char nslookup_usage[] =
"only implementing non-interactive mode\n" "nslookup [HOST]\n\n"
"I totally forgot nslookup even had an interactive mode\n"
; ;
/* */ /* I have to see how the real nslookup does this.
* I could dig through /etc/resolv.conf, but is there a
* better (programatic) way?
*/
static void static void
server_fprint(FILE *dst) server_fprint(FILE *dst)
{ {
@ -67,7 +77,9 @@ addr_fprint(char *addr, FILE *dst)
return 0; return 0;
} }
/* */ /* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+
* into a uint32_t
*/
static uint32_t static uint32_t
str_to_addr(const char *addr) str_to_addr(const char *addr)
{ {
@ -86,59 +98,63 @@ str_to_addr(const char *addr)
return htonl(ip); return htonl(ip);
} }
/* */ /* takes the NULL-terminated array h_addr_list, and
* prints its contents appropriately
*/
static int static int
addr_list_fprint(char **h_addr_list, FILE *dst) addr_list_fprint(char **h_addr_list, FILE *dst)
{ {
int i; int i, j;
char *addr_string = (h_addr_list[1]) char *addr_string = (h_addr_list[1])
? "Addresses" ? "Addresses"
: "Address"; : "Address";
fprintf(dst, "%s: ", addr_string); fprintf(dst, "%s: ", addr_string);
for (i = 0; h_addr_list[i]; i++) { for (i = 0, j = 0; h_addr_list[i]; i++, j++) {
addr_fprint(h_addr_list[i], dst); addr_fprint(h_addr_list[i], dst);
if (h_addr_list[i+1]) {
fprintf(dst, ", "); /* real nslookup does this */
if (j == 4) {
if (h_addr_list[i+1]) {
fprintf(dst, "\n ");
}
j = 0;
} else {
if (h_addr_list[i+1]) {
fprintf(dst, ", ");
}
} }
} }
fprintf(dst,"\n"); fprintf(dst,"\n");
return 0; return 0;
} }
/* */ /* gethostbyaddr wrapper */
static struct hostent * static struct hostent *
lookup_by_name(const char *hostname) gethostbyaddr_wrapper(const char *address)
{ {
struct hostent *host; struct in_addr addr;
host = gethostbyname(hostname); addr.s_addr = str_to_addr(address);
return gethostbyaddr((char *) &addr, 4, AF_INET); /* IPv4 only for now */
}
/* print the results as nslookup would */
static struct hostent *
hostent_fprint(struct hostent *host, FILE *dst)
{
if (host) { if (host) {
fprintf(stdout, "Name: %s\n", host->h_name); fprintf(dst, "Name: %s\n", host->h_name);
addr_list_fprint(host->h_addr_list, stdout); addr_list_fprint(host->h_addr_list, dst);
} else { } else {
herror("crap"); fprintf(dst, "*** %s\n", hstrerror(h_errno));
} }
return host; return host;
} }
/* */
static struct hostent *
lookup_by_addr(const char *addr)
{
struct hostent *host;
host = gethostbyaddr(addr, 4, AF_INET); /* IPv4 only for now */ /* naive function to check whether char *s is an ip address */
if (host) {
fprintf(stdout, "Name: %s\n", host->h_name);
addr_list_fprint(host->h_addr_list, stdout);
} else {
herror("crap");
}
return host;
}
/* */
static int static int
is_ip_address(const char *s) is_ip_address(const char *s)
{ {
@ -153,16 +169,20 @@ is_ip_address(const char *s)
int int
nslookup_main(int argc, char **argv) nslookup_main(int argc, char **argv)
{ {
struct in_addr addr; struct hostent *host;
if (argc < 2) {
usage(nslookup_usage);
}
server_fprint(stdout); server_fprint(stdout);
if (is_ip_address(argv[1])) { if (is_ip_address(argv[1])) {
addr.s_addr = str_to_addr(argv[1]); host = gethostbyaddr_wrapper(argv[1]);
lookup_by_addr((char *) &addr);
} else { } else {
lookup_by_name(argv[1]); host = gethostbyname(argv[1]);
} }
hostent_fprint(host, stdout);
return 0; return 0;
} }
/* $Id: nslookup.c,v 1.1 2000/01/29 12:59:01 beppu Exp $ */ /* $Id: nslookup.c,v 1.2 2000/01/30 09:47:16 beppu Exp $ */