1 files changed, 16 insertions, 9 deletions

diff --git a/ipsvd/udp_io.c b/ipsvd/udp_io.c
index 68999d44d..2efc15913 100644
--- a/ipsvd/udp_io.c
+++ b/ipsvd/udp_io.c
@@ -18,12 +18,13 @@ socket_want_pktinfo(int fd)
 #ifdef IP_PKTINFO
         setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &const_int_1, sizeof(int));
 #endif
-#ifdef IPV6_PKTINFO
+#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
         setsockopt(fd, IPPROTO_IPV6, IPV6_PKTINFO, &const_int_1, sizeof(int));
 #endif
 }
 
 
+#ifdef UNUSED
 ssize_t
 send_to_from(int fd, void *buf, size_t len, int flags,
                 const struct sockaddr *from, const struct sockaddr *to,
@@ -34,8 +35,11 @@ send_to_from(int fd, void *buf, size_t len, int flags,
 #else
         struct iovec iov[1];
         struct msghdr msg;
-        char cbuf[LSA_SIZEOF_SA];
-        /* actually, max(sizeof(in_pktinfo),sizeof(in6_pktinfo)) */
+        char cbuf[sizeof(struct in_pktinfo)
+#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
+                | sizeof(struct in6_pktinfo) /* (a|b) is poor man's max(a,b) */
+#endif
+        ];
         struct cmsghdr* cmsgptr;
 
         if (from->sa_family != AF_INET
@@ -73,11 +77,11 @@ send_to_from(int fd, void *buf, size_t len, int flags,
                 /* pktptr->ipi_ifindex = 0; -- already done by memset(cbuf...) */
                 pktptr->ipi_spec_dst = ((struct sockaddr_in*)from)->sin_addr;
         }
-#if ENABLE_FEATURE_IPV6 && defined(IP6_PKTINFO)
+#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
         else if (to->sa_family == AF_INET6 && from->sa_family == AF_INET6) {
                 struct in6_pktinfo *pktptr;
                 cmsgptr->cmsg_level = IPPROTO_IPV6;
-                cmsgptr->cmsg_type = IP6_PKTINFO;
+                cmsgptr->cmsg_type = IPV6_PKTINFO;
                 cmsgptr->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
                 pktptr = (struct in6_pktinfo *)(CMSG_DATA(cmsgptr));
                 /* pktptr->ipi6_ifindex = 0; -- already done by memset(cbuf...) */
@@ -87,8 +91,12 @@ send_to_from(int fd, void *buf, size_t len, int flags,
         return sendmsg(fd, &msg, flags);
 #endif
 }
+#endif /* UNUSED */
 
-/* NB: this will never set port# in *to! */
+/* NB: this will never set port# in 'to'!
+ * _Only_ IP/IPv6 address part of 'to' is _maybe_ modified.
+ * Typical usage is to preinit it with "default" value
+ * before calling recv_from_to(). */
 ssize_t
 recv_from_to(int fd, void *buf, size_t len, int flags,
                 struct sockaddr *from, struct sockaddr *to,
@@ -123,7 +131,6 @@ recv_from_to(int fd, void *buf, size_t len, int flags,
                 return recv_length;
 
         /* Here we try to retrieve destination IP and memorize it */
-        memset(to, 0, sa_size);
         for (cmsgptr = CMSG_FIRSTHDR(&msg);
                         cmsgptr != NULL;
                         cmsgptr = CMSG_NXTHDR(&msg, cmsgptr)
@@ -138,9 +145,9 @@ recv_from_to(int fd, void *buf, size_t len, int flags,
 #undef pktinfo
                         break;
                 }
-#if ENABLE_FEATURE_IPV6 && defined(IP6_PKTINFO)
+#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
                 if (cmsgptr->cmsg_level == IPPROTO_IPV6
-                 && cmsgptr->cmsg_type == IP6_PKTINFO
+                 && cmsgptr->cmsg_type == IPV6_PKTINFO
                 ) {
 #define pktinfo(cmsgptr) ( (struct in6_pktinfo*)(CMSG_DATA(cmsgptr)) )
                         to->sa_family = AF_INET6;