[*] Initial commit

lonetix/sys/ip_common.c

@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+/**
+ * \file sys/ip_common.c
+ *
+ * Cross-system Internet Protocol functionality implementation.
+ *
+ * \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
+ * \author    Lorenzo Cogotti
+ */
+
+#include "sys/ip.h"
+
+#include "sys/endian.h"
+#include "numlib.h"
+
+#include <string.h>
+
+char *Ipv4_AdrToString(const Ipv4adr *adr, char *dest)
+{
+	char *ptr = dest;
+	ptr = Utoa(adr->bytes[0], ptr); *ptr++ = '.';
+	ptr = Utoa(adr->bytes[1], ptr); *ptr++ = '.';
+	ptr = Utoa(adr->bytes[2], ptr); *ptr++ = '.';
+	ptr = Utoa(adr->bytes[3], ptr);
+	return ptr;
+}
+
+char *Ipv6_AdrToString(const Ipv6adr *adr, char *dest)
+{
+	char *ptr = dest;
+	if (IS_IPV6_V4MAPPED(adr)) {
+		// IPv4 mapped to IPv6 (starts with 0:0:0:0:0:0:ffff)
+		memcpy(ptr, "::ffff:", 7);
+		ptr += 7;
+
+		ptr = Utoa(adr->bytes[0], ptr); *ptr++ = '.';
+		ptr = Utoa(adr->bytes[1], ptr); *ptr++ = '.';
+		ptr = Utoa(adr->bytes[2], ptr); *ptr++ = '.';
+		ptr = Utoa(adr->bytes[3], ptr);
+	} else {
+		// Regular IPv6
+		ptr = Xtoa(beswap16(adr->words[0]), ptr); *ptr++ = ':';
+		ptr = Xtoa(beswap16(adr->words[1]), ptr); *ptr++ = ':';
+		ptr = Xtoa(beswap16(adr->words[2]), ptr); *ptr++ = ':';
+		ptr = Xtoa(beswap16(adr->words[3]), ptr); *ptr++ = ':';
+		ptr = Xtoa(beswap16(adr->words[4]), ptr); *ptr++ = ':';
+		ptr = Xtoa(beswap16(adr->words[5]), ptr); *ptr++ = ':';
+		ptr = Xtoa(beswap16(adr->words[6]), ptr); *ptr++ = ':';
+		ptr = Xtoa(beswap16(adr->words[7]), ptr);
+
+		// Replace longest /(^0|:)[:0]{2,}/ with "::"
+		unsigned i, j, n, best, max;
+		for (i = best = 0, max = 2; dest[i] != '\0'; i++) {
+			if (i > 0 && dest[i] != ':')
+				continue;
+
+			// Count the number of consecutive 0 in this substring
+			n = 0;
+			for (j = i; dest[j] != '\0'; j++) {
+				if (dest[j] != ':' && dest[j] != '0')
+					break;
+
+				n++;
+			}
+
+			// Store the position if this is the best we've seen so far
+			if (n > max) {
+				best = i;
+				max = n;
+			}
+		}
+
+		ptr = dest + i;
+		if (max > 3) {
+			// Compress the string
+			dest[best] = ':';
+			dest[best + 1] = ':';
+
+			unsigned len = i - best - max;
+			memmove(&dest[best + 2], &dest[best + max], len + 1);
+			ptr = &dest[best + 2 + len];
+		}
+	}
+
+	return ptr;
+}
+
+char *Ip_AdrToString(const Ipadr *addr, char *dest)
+{
+	switch (addr->family) {
+	case IP4: return Ipv4_AdrToString(&addr->v4, dest);
+	case IP6: return Ipv6_AdrToString(&addr->v6, dest);
+	default:  return NULL;
+	}
+}
+
+static Boolean Ip_IsStringIpv4(const char *s)
+{
+	// A well formed IPv4 address contains one dot in chars [1,3]
+	// x.
+	// xx.
+	// xxx.
+
+	for (int i = 1; i < 4; i++) {
+		if (s[i-1] == '\0')
+			return FALSE;
+		if (s[i] == '.')
+			return TRUE;
+	}
+	return FALSE;
+}
+
+Judgement Ip_StringToAdr(const char *s, Ipadr *dest)
+{
+	if (Ip_IsStringIpv4(s)) {
+		if (Ipv4_StringToAdr(s, &dest->v4) != OK)
+			return NG;
+
+		dest->family = IP4;
+	} else {
+		if (Ipv6_StringToAdr(s, &dest->v6) != OK)
+			return NG;
+
+		dest->family = IP6;
+	}
+
+	return OK;
+}