add support for reverse name lookups from hosts file to getnameinfo

[musl] / src / network / getnameinfo.c

diff --git a/src/network/getnameinfo.c b/src/network/getnameinfo.c
index 6962ed1..708ec5e 100644 (file)
--- a/src/network/getnameinfo.c
+++ b/src/network/getnameinfo.c
@@ -6,6 +6,9 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <net/if.h>
+#include <ctype.h>
+#include "lookup.h"
+#include "stdio_impl.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);
@@ -42,6 +45,47 @@ static void mkptr6(char *s, const unsigned char *ip)
        strcpy(s, "ip6.arpa");
 }
 
+static char *reverse_hosts(char *buf, const unsigned char *a, unsigned scopeid, int family)
+{
+       char line[512], *p, *z;
+       unsigned char _buf[1032], atmp[16];
+       struct address iplit;
+       FILE _f, *f = __fopen_rb_ca("/etc/hosts", &_f, _buf, sizeof _buf);
+       if (!f) return 0;
+       if (family == AF_INET) {
+               memcpy(atmp+12, a, 4);
+               memcpy(atmp, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+               a = atmp;
+       }
+       while (fgets(line, sizeof line, f)) {
+               if ((p=strchr(line, '#'))) *p++='\n', *p=0;
+
+               for (p=line; *p && !isspace(*p); p++);
+               *p++ = 0;
+               if (__lookup_ipliteral(&iplit, line, AF_UNSPEC)<=0)
+                       continue;
+
+               if (iplit.family == AF_INET) {
+                       memcpy(iplit.addr+12, iplit.addr, 4);
+                       memcpy(iplit.addr, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+                       iplit.scopeid = 0;
+               }
+
+               if (memcmp(a, iplit.addr, 16) || iplit.scopeid != scopeid)
+                       continue;
+                       
+               for (; *p && isspace(*p); p++);
+               for (z=p; *z && !isspace(*z); z++);
+               *z = 0;
+               if (z-p < 256) {
+                       memcpy(buf, p, z-p+1);
+                       break;
+               }
+       }
+       __fclose_ca(f);
+       return 0;
+}
+
 static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet)
 {
        char tmp[256];
@@ -62,13 +106,14 @@ int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
        char buf[256], num[3*sizeof(int)+1];
        int af = sa->sa_family;
        unsigned char *a;
-       unsigned x;
+       unsigned scopeid;
 
        switch (af) {
        case AF_INET:
                a = (void *)&((struct sockaddr_in *)sa)->sin_addr;
                if (sl != sizeof(struct sockaddr_in)) return EAI_FAMILY;
                mkptr4(ptr, a);
+               scopeid = 0;
                break;
        case AF_INET6:
                a = (void *)&((struct sockaddr_in6 *)sa)->sin6_addr;
@@ -77,6 +122,7 @@ int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
                        mkptr6(ptr, a);
                else
                        mkptr4(ptr, a+12);
+               scopeid = ((struct sockaddr_in6 *)sa)->sin6_scope_id;
                break;
        default:
                return EAI_FAMILY;
@@ -85,6 +131,9 @@ int getnameinfo(const struct sockaddr *restrict sa, socklen_t sl,
        if (node && nodelen) {
                buf[0] = 0;
                if (!(flags & NI_NUMERICHOST)) {
+                       reverse_hosts(buf, a, scopeid, af);
+               }
+               if (!*buf && !(flags & NI_NUMERICHOST)) {
                        unsigned char query[18+PTR_MAX], reply[512];
                        int qlen = __res_mkquery(0, ptr, 1, RR_PTR,
                                0, 0, 0, query, sizeof query);
@@ -96,15 +145,14 @@ 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)) {
+                       if (scopeid) {
                                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);
+                                       p = if_indextoname(scopeid, tmp+1);
                                if (!p)
-                                       p = itoa(num, x);
+                                       p = itoa(num, scopeid);
                                *--p = '%';
                                strcat(buf, p);
                        }