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add support for ipv6 scope_id to getaddrinfo and getnameinfo

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for all address types, a scope_id specified as a decimal value is
accepted. for addresses with link-local scope, a string containing the
interface name is also accepted.

some changes are made to error handling to avoid unwanted fallbacks in
the case where the scope_id is invalid: if an earlier name lookup
backend fails with an error rather than simply "0 results", this
failure now suppresses any later attempts with other backends.

in getnameinfo, a light "itoa" type function is added for generating
decimal scope_id results, and decimal port strings for services are
also generated using this function now so as not to pull in the
dependency on snprintf.

in netdb.h, a definition for the NI_NUMERICSCOPE flag is added. this
is required by POSIX (it was previously missing) and needed to allow
callers to suppress interface-name lookups.
This commit is contained in:
Rich Felker
2014-06-04 02:24:38 -04:00
parent 8041af5988
commit bdad2fefb2
4 changed files with 57 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/network/getnameinfo.c
+28 -4
View File
@@ -5,6 +5,7 @@
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
int __dns_parse(const unsigned char *, int, int (*)(void *, int, const void *, int, const void *), void *);
int __dn_expand(const unsigned char *, const unsigned char *, const unsigned char *, char *, int);
@@ -14,6 +15,16 @@ int __res_send(const unsigned char *, int, unsigned char *, int);
#define PTR_MAX (64 + sizeof ".in-addr.arpa")
#define RR_PTR 12
static char *itoa(char *p, unsigned x) {
p += 3*sizeof(int);
*--p = 0;
do {
*--p = '0' + x % 10;
x /= 10;
} while (x);
return p;
}
static void mkptr4(char *s, const unsigned char *ip)
{
sprintf(s, "%d.%d.%d.%d.in-addr.arpa",
@@ -48,9 +59,10 @@ int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
int flags)
{
char ptr[PTR_MAX];
char buf[256];
char buf[256], num[3*sizeof(int)+1];
int af = sa->sa_family;
unsigned char *a;
unsigned x;
switch (af) {
case AF_INET:
@@ -84,16 +96,28 @@ int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
if (!*buf) {
if (flags & NI_NAMEREQD) return EAI_NONAME;
inet_ntop(af, a, buf, sizeof buf);
if (af == AF_INET6 &&
(x = ((struct sockaddr_in6 *)sa)->sin6_scope_id)) {
char *p = 0, tmp[IF_NAMESIZE+1];
if (!(flags & NI_NUMERICSCOPE) &&
(IN6_IS_ADDR_LINKLOCAL(a) ||
IN6_IS_ADDR_MC_LINKLOCAL(a)))
p = if_indextoname(x, tmp+1);
if (!p)
p = itoa(num, x);
*--p = '%';
strcat(buf, p);
}
}
if (strlen(buf) >= nodelen) return EAI_OVERFLOW;
strcpy(node, buf);
}
if (serv && servlen) {
if (snprintf(buf, sizeof buf, "%d",
ntohs(((struct sockaddr_in *)sa)->sin_port))>=servlen)
char *p = itoa(num, ntohs(((struct sockaddr_in *)sa)->sin_port));
if (strlen(p) >= servlen)
return EAI_OVERFLOW;
strcpy(serv, buf);
strcpy(serv, p);
}
return 0;