diff options
Diffstat (limited to 'networking')
| -rw-r--r-- | networking/nslookup.c | 88 |
1 files changed, 54 insertions, 34 deletions
diff --git a/networking/nslookup.c b/networking/nslookup.c index 0a2a574..82d3b36 100644 --- a/networking/nslookup.c +++ b/networking/nslookup.c @@ -32,14 +32,24 @@ #include <sys/types.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[] = -"only implementing non-interactive mode\n" -"I totally forgot nslookup even had an interactive mode\n" + "nslookup [HOST]\n\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 server_fprint(FILE *dst) { @@ -67,7 +77,9 @@ addr_fprint(char *addr, FILE *dst) return 0; } -/* */ +/* changes a c-string matching the perl regex \d+\.\d+\.\d+\.\d+ + * into a uint32_t + */ static uint32_t str_to_addr(const char *addr) { @@ -86,59 +98,63 @@ str_to_addr(const char *addr) return htonl(ip); } -/* */ +/* takes the NULL-terminated array h_addr_list, and + * prints its contents appropriately + */ static int addr_list_fprint(char **h_addr_list, FILE *dst) { - int i; + int i, j; char *addr_string = (h_addr_list[1]) ? "Addresses" : "Address"; 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); - 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"); return 0; } -/* */ +/* gethostbyaddr wrapper */ static struct hostent * -lookup_by_name(const char *hostname) +gethostbyaddr_wrapper(const char *address) { - struct hostent *host; + struct in_addr addr; - host = gethostbyname(hostname); - if (host) { - fprintf(stdout, "Name: %s\n", host->h_name); - addr_list_fprint(host->h_addr_list, stdout); - } else { - herror("crap"); - } - return host; + 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 * -lookup_by_addr(const char *addr) +hostent_fprint(struct hostent *host, FILE *dst) { - struct hostent *host; - - host = gethostbyaddr(addr, 4, AF_INET); /* IPv4 only for now */ if (host) { - fprintf(stdout, "Name: %s\n", host->h_name); - addr_list_fprint(host->h_addr_list, stdout); + fprintf(dst, "Name: %s\n", host->h_name); + addr_list_fprint(host->h_addr_list, dst); } else { - herror("crap"); + fprintf(dst, "*** %s\n", hstrerror(h_errno)); } return host; } -/* */ + +/* naive function to check whether char *s is an ip address */ static int is_ip_address(const char *s) { @@ -153,16 +169,20 @@ is_ip_address(const char *s) int nslookup_main(int argc, char **argv) { - struct in_addr addr; + struct hostent *host; + + if (argc < 2) { + usage(nslookup_usage); + } server_fprint(stdout); if (is_ip_address(argv[1])) { - addr.s_addr = str_to_addr(argv[1]); - lookup_by_addr((char *) &addr); + host = gethostbyaddr_wrapper(argv[1]); } else { - lookup_by_name(argv[1]); + host = gethostbyname(argv[1]); } + hostent_fprint(host, stdout); 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 $ */ |