Simplify address family handling, ditch inet_ntop(3)

Reduce duplicate code and use getnameinfo(3) for IPv4 as well.

This commit is the equivalent of sbin/resolvd/resolvd.c revision 1.21
"Simplify address family handling, ditch inet_ntop(3)".

OK florian

diff --git a/sbin/unwind/resolver.c b/sbin/unwind/resolver.c
index 1d7019c..75d3c2c 100644 (file)
--- a/sbin/unwind/resolver.c
+++ b/sbin/unwind/resolver.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: resolver.c,v 1.151 2021/11/16 16:30:42 kn Exp $       */
+/*     $OpenBSD: resolver.c,v 1.152 2021/11/16 16:37:52 kn Exp $       */
 
 /*
  * Copyright (c) 2018 Florian Obser <florian@openbsd.org>
@@ -1969,9 +1969,9 @@ replace_autoconf_forwarders(struct imsg_rdns_proposal *rdns_proposal)
 {
        struct uw_forwarder_head         new_forwarder_list;
        struct uw_forwarder             *uw_forwarder, *tmp;
+       size_t                           addrsz;
        int                              i, rdns_count, af, changed = 0;
-       char                             ntopbuf[INET6_ADDRSTRLEN], *src;
-       const char                      *ns;
+       char                             hostbuf[INET6_ADDRSTRLEN], *src;
 
        TAILQ_INIT(&new_forwarder_list);
        af = rdns_proposal->rtdns.sr_family;
@@ -1979,65 +1979,62 @@ replace_autoconf_forwarders(struct imsg_rdns_proposal *rdns_proposal)
 
        switch (af) {
        case AF_INET:
-               rdns_count = (rdns_proposal->rtdns.sr_len -
-                   offsetof(struct sockaddr_rtdns, sr_dns)) /
-                   sizeof(struct in_addr);
+               addrsz = sizeof(struct in_addr);
                break;
        case AF_INET6:
-               rdns_count = (rdns_proposal->rtdns.sr_len -
-                   offsetof(struct sockaddr_rtdns, sr_dns)) /
-                   sizeof(struct in6_addr);
+               addrsz = sizeof(struct in6_addr);
                break;
        default:
                log_warnx("%s: unsupported address family: %d", __func__, af);
                return;
        }
 
+       rdns_count = (rdns_proposal->rtdns.sr_len -
+           offsetof(struct sockaddr_rtdns, sr_dns)) / addrsz;
+
        for (i = 0; i < rdns_count; i++) {
                struct sockaddr_storage ss;
                struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss;
-               struct in_addr addr4;
+               struct sockaddr_in *sin = (struct sockaddr_in *)&ss;
                int err;
 
+               memset(&ss, 0, sizeof(ss));
+               ss.ss_family = af;
                switch (af) {
                case AF_INET:
-                       memcpy(&addr4, src, sizeof(struct in_addr));
-                       src += sizeof(struct in_addr);
-                       if (addr4.s_addr == htonl(INADDR_LOOPBACK))
-                               continue;
-                       ns = inet_ntop(af, &addr4, ntopbuf,
-                           INET6_ADDRSTRLEN);
+                       memcpy(&sin->sin_addr, src, addrsz);
+                       if (sin->sin_addr.s_addr == htonl(INADDR_LOOPBACK))
+                               goto skip;
+                       ss.ss_len = sizeof(*sin);
                        break;
                case AF_INET6:
-                       memset(&ss, 0, sizeof(ss));
-                       memcpy(&sin6->sin6_addr, src, sizeof(sin6->sin6_addr));
-                       src += sizeof(struct in6_addr);
+                       memcpy(&sin6->sin6_addr, src, addrsz);
                        if (IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
-                               continue;
+                               goto skip;
                        if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
                                sin6->sin6_scope_id = rdns_proposal->if_index;
                        ss.ss_len = sizeof(*sin6);
-                       ss.ss_family = af;
-                       if ((err = getnameinfo((struct sockaddr *)&ss, ss.ss_len,
-                           ntopbuf, sizeof(ntopbuf),
-                           NULL, 0, NI_NUMERICHOST)) != 0) {
-                               log_warnx("getnameinfo: %s", gai_strerror(err));
-                               continue;
-                       }
-                       ns = ntopbuf;
                        break;
                }
+               if ((err = getnameinfo((struct sockaddr *)&ss, ss.ss_len,
+                   hostbuf, sizeof(hostbuf), NULL, 0, NI_NUMERICHOST)) != 0) {
+                       log_warnx("getnameinfo: %s", gai_strerror(err));
+                       goto skip;
+               }
 
                if ((uw_forwarder = calloc(1, sizeof(struct uw_forwarder))) ==
                    NULL)
                        fatal(NULL);
-               if (strlcpy(uw_forwarder->ip, ns, sizeof(uw_forwarder->ip))
+               if (strlcpy(uw_forwarder->ip, hostbuf, sizeof(uw_forwarder->ip))
                    >= sizeof(uw_forwarder->ip))
                        fatalx("strlcpy");
                uw_forwarder->port = 53;
                uw_forwarder->if_index = rdns_proposal->if_index;
                uw_forwarder->src = rdns_proposal->src;
                TAILQ_INSERT_TAIL(&new_forwarder_list, uw_forwarder, entry);
+
+skip:
+               src += addrsz;
        }
 
        TAILQ_FOREACH(tmp, &autoconf_forwarder_list, entry) {