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nslookup: full circle. Here we started IPv6 work. Use "new API"

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and thus save a few bytes.
This commit is contained in:
Denis Vlasenko
2007-01-22 22:43:05 +00:00
parent fdcd7c4237
commit 448f0241e0
3 changed files with 132 additions and 48 deletions
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117
networking/nslookup.c
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@@ -47,7 +47,7 @@
* ns3.kernel.org internet address = 204.152.191.36
*/
static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
/*static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
{
if (buflen <= 0) return -1;
buf[0] = '\0';
@@ -61,9 +61,11 @@ static int sockaddr_to_dotted(struct sockaddr *saddr, char *buf, int buflen)
}
return -1;
}
*/
static int print_host(const char *hostname, const char *header)
{
#if 0
char str[128]; /* IPv6 address will fit, hostnames hopefully too */
struct addrinfo *result = NULL;
int rc;
@@ -76,6 +78,7 @@ static int print_host(const char *hostname, const char *header)
hint.ai_socktype = SOCK_STREAM;
// hint.ai_flags = AI_CANONNAME;
rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
if (!rc) {
struct addrinfo *cur = result;
// printf("%s\n", cur->ai_canonname); ?
@@ -93,6 +96,75 @@ static int print_host(const char *hostname, const char *header)
}
freeaddrinfo(result);
return (rc != 0);
#else
/* We can't use host2sockaddr() - we want to get ALL addresses,
* not just one */
struct addrinfo *result = NULL;
int rc;
struct addrinfo hint;
memset(&hint, 0 , sizeof(hint));
/* hint.ai_family = AF_UNSPEC; - zero anyway */
/* Needed. Or else we will get each address thrice (or more)
* for each possible socket type (tcp,udp,raw...): */
hint.ai_socktype = SOCK_STREAM;
// hint.ai_flags = AI_CANONNAME;
rc = getaddrinfo(hostname, NULL /*service*/, &hint, &result);
if (!rc) {
struct addrinfo *cur = result;
unsigned cnt = 0;
printf("%-10s %s\n", header, hostname);
// printf("%s\n", cur->ai_canonname); ?
while (cur) {
char *dotted, *revhost;
dotted = xmalloc_sockaddr2dotted_noport(cur->ai_addr, cur->ai_addrlen);
revhost = xmalloc_sockaddr2hostonly_noport(cur->ai_addr, cur->ai_addrlen);
printf("Address %u: %s%c", ++cnt, dotted, revhost ? ' ' : '\n');
if (revhost) {
puts(revhost);
if (ENABLE_FEATURE_CLEAN_UP)
free(revhost);
}
if (ENABLE_FEATURE_CLEAN_UP)
free(dotted);
cur = cur->ai_next;
}
} else {
#if ENABLE_VERBOSE_RESOLUTION_ERRORS
bb_error_msg("getaddrinfo('%s') failed: %s", hostname, gai_strerror(rc));
#else
bb_error_msg("can't resolve '%s'", hostname);
#endif
}
if (ENABLE_FEATURE_CLEAN_UP)
freeaddrinfo(result);
return (rc != 0);
#endif
}
/* lookup the default nameserver and display it */
static void server_print(void)
{
char *server;
server = xmalloc_sockaddr2dotted_noport((struct sockaddr*)&_res.nsaddr_list[0],
sizeof(struct sockaddr_in));
/* I honestly don't know what to do if DNS server has _IPv6 address_.
* Probably it is listed in
* _res._u._ext_.nsaddrs[MAXNS] (of type "struct sockaddr_in6*" each)
* but how to find out whether resolver uses
* _res.nsaddr_list[] or _res._u._ext_.nsaddrs[], or both?
* Looks like classic design from hell, BIND-grade. Hard to surpass. */
print_host(server, "Server:");
if (ENABLE_FEATURE_CLEAN_UP)
free(server);
puts("");
}
@@ -109,40 +181,27 @@ static void set_default_dns(char *server)
}
/* lookup the default nameserver and display it */
static void server_print(void)
{
char str[INET6_ADDRSTRLEN];
sockaddr_to_dotted((struct sockaddr*)&_res.nsaddr_list[0], str, sizeof(str));
print_host(str, "Server:");
puts("");
}
int nslookup_main(int argc, char **argv)
{
/*
* initialize DNS structure _res used in printing the default
* name server and in the explicit name server option feature.
*/
res_init();
/*
* We allow 1 or 2 arguments.
* The first is the name to be looked up and the second is an
* optional DNS server with which to do the lookup.
* More than 3 arguments is an error to follow the pattern of the
* standard nslookup
*/
/* We allow 1 or 2 arguments.
* The first is the name to be looked up and the second is an
* optional DNS server with which to do the lookup.
* More than 3 arguments is an error to follow the pattern of the
* standard nslookup */
if (argc < 2 || *argv[1] == '-' || argc > 3)
bb_show_usage();
else if(argc == 3)
/* initialize DNS structure _res used in printing the default
* name server and in the explicit name server option feature. */
res_init();
/* rfc2133 says this enables IPv6 lookups */
/* (but it also says "may be enabled in /etc/resolv.conf|) */
/*_res.options |= RES_USE_INET6;*/
if(argc == 3)
set_default_dns(argv[2]);
server_print();
return print_host(argv[1], "Name: ");
return print_host(argv[1], "Name:");
}