Add inet_pton for Windows XP support

src/network/stk_ipv6.cpp

@@ -24,13 +24,6 @@
 #    include <winsock2.h>
 #    include <ws2tcpip.h>
 
-extern "C"
-{
-#ifndef InetPtopN
-   WINSOCK_API_LINKAGE  INT WSAAPI inet_pton(INT Family, PCSTR pszAddrString, PVOID pAddrBuf);
-#endif
-}
-
 #else
 #    include <winsock2.h>
 #    include <in6addr.h>
@@ -52,6 +45,157 @@ extern "C"
 #include <array>
 #include <string>
 
+// ============================================================================
+// For Windows XP support
+#define IN6ADDRSZ       16
+#define INADDRSZ         4
+#define INT16SZ          2
+
+static int
+stk_inet_pton4(const char *src, unsigned char *dst)
+{
+    static const char digits[] = "0123456789";
+    int saw_digit, octets, ch;
+    unsigned char tmp[INADDRSZ], *tp;
+
+    saw_digit = 0;
+    octets = 0;
+    tp = tmp;
+    *tp = 0;
+    while((ch = *src++) != '\0')
+    {
+        const char *pch;
+
+        pch = strchr(digits, ch);
+        if(pch)
+        {
+            unsigned int val = *tp * 10 + (unsigned int)(pch - digits);
+
+            if(saw_digit && *tp == 0)
+                return (0);
+            if(val > 255)
+                return (0);
+            *tp = (unsigned char)val;
+            if(! saw_digit)
+            {
+                if(++octets > 4)
+                    return (0);
+                saw_digit = 1;
+            }
+        }
+        else if(ch == '.' && saw_digit)
+        {
+            if(octets == 4)
+                return (0);
+            *++tp = 0;
+            saw_digit = 0;
+        }
+        else
+            return (0);
+    }
+    if(octets < 4)
+        return (0);
+    memcpy(dst, tmp, INADDRSZ);
+    return (1);
+}
+
+static int
+stk_inet_pton6(const char *src, void *dest)
+{
+    unsigned char *dst = (unsigned char*)dest;
+    static const char xdigits_l[] = "0123456789abcdef",
+        xdigits_u[] = "0123456789ABCDEF";
+    unsigned char tmp[IN6ADDRSZ], *tp, *endp, *colonp;
+    const char *curtok;
+    int ch, saw_xdigit;
+    size_t val;
+
+    memset((tp = tmp), 0, IN6ADDRSZ);
+    endp = tp + IN6ADDRSZ;
+    colonp = NULL;
+    /* Leading :: requires some special handling. */
+    if(*src == ':')
+    {
+        if(*++src != ':')
+            return (0);
+    }
+    curtok = src;
+    saw_xdigit = 0;
+    val = 0;
+    while((ch = *src++) != '\0')
+    {
+        const char *xdigits;
+        const char *pch;
+
+        pch = strchr((xdigits = xdigits_l), ch);
+        if(!pch)
+            pch = strchr((xdigits = xdigits_u), ch);
+        if(pch != NULL)
+        {
+            val <<= 4;
+            val |= (pch - xdigits);
+            if(++saw_xdigit > 4)
+                return (0);
+            continue;
+        }
+        if(ch == ':')
+        {
+            curtok = src;
+            if(!saw_xdigit)
+            {
+                if(colonp)
+                    return (0);
+                colonp = tp;
+                continue;
+            }
+            if(tp + INT16SZ > endp)
+                return (0);
+            *tp++ = (unsigned char) ((val >> 8) & 0xff);
+            *tp++ = (unsigned char) (val & 0xff);
+            saw_xdigit = 0;
+            val = 0;
+            continue;
+        }
+        if(ch == '.' && ((tp + INADDRSZ) <= endp) &&
+            stk_inet_pton4(curtok, tp) > 0)
+        {
+            tp += INADDRSZ;
+            saw_xdigit = 0;
+            break;    /* '\0' was seen by stk_inet_pton4(). */
+        }
+        return (0);
+    }
+    if(saw_xdigit)
+    {
+        if(tp + INT16SZ > endp)
+            return (0);
+        *tp++ = (unsigned char) ((val >> 8) & 0xff);
+        *tp++ = (unsigned char) (val & 0xff);
+    }
+    if(colonp != NULL)
+    {
+        /*
+        * Since some memmove()'s erroneously fail to handle
+        * overlapping regions, we'll do the shift by hand.
+        */
+        const ssize_t n = tp - colonp;
+        ssize_t i;
+
+        if(tp == endp)
+            return (0);
+        for(i = 1; i <= n; i++)
+        {
+            *(endp - i) = *(colonp + n - i);
+            *(colonp + n - i) = 0;
+        }
+        tp = endp;
+    }
+    if(tp != endp)
+        return (0);
+    memcpy(dst, tmp, IN6ADDRSZ);
+    return (1);
+}
+
 // ============================================================================
 // Android STK seems to crash when using inet_ntop so we copy it from linux
 static const char *
@@ -283,7 +427,7 @@ void andIPv6(struct in6_addr* ipv6, const struct in6_addr* mask)
 extern "C" int64_t upperIPv6(const char* ipv6)
 {
     struct in6_addr v6_in;
-    if (inet_pton(AF_INET6, ipv6, &v6_in) != 1)
+    if (stk_inet_pton6(ipv6, &v6_in) != 1)
         return 0;
     uint64_t result = 0;
     unsigned shift = 56;
@@ -303,13 +447,13 @@ extern "C" int insideIPv6CIDR(const char* ipv6_cidr, const char* ipv6_in)
     if (mask_location == NULL)
         return 0;
     struct in6_addr v6_in;
-    if (inet_pton(AF_INET6, ipv6_in, &v6_in) != 1)
+    if (stk_inet_pton6(ipv6_in, &v6_in) != 1)
         return 0;
 
     char ipv6[INET6_ADDRSTRLEN] = {};
     memcpy(ipv6, ipv6_cidr, mask_location - ipv6_cidr);
     struct in6_addr cidr;
-    if (inet_pton(AF_INET6, ipv6, &cidr) != 1)
+    if (stk_inet_pton6(ipv6, &cidr) != 1)
         return 0;
 
     int mask_length = atoi(mask_location + 1);