[SERVER] Check which dnbd3 devices are idle and ready to use for proxy mode

[SERVER] Skeleton of server-to-server communication
[SERVER] Update access-time of images in use by actual clients
[*] Add dnbd3_host_t type to handle address+port+addrtype consistently across the project

1 files changed, 162 insertions, 0 deletions

diff --git a/src/server/helper.c b/src/server/helper.c
new file mode 100644
index 0000000..293fa36
--- /dev/null
+++ b/src/server/helper.c
@@ -0,0 +1,162 @@
+#include "helper.h"
+#include <arpa/inet.h>
+#include <string.h>
+#include <stdlib.h>
+#include <glib/gmacros.h>
+#include "../config.h"
+
+/**
+ * Parse IPv4 or IPv6 address in string representation to a suitable format usable by the BSD socket library
+ * @string eg. "1.2.3.4" or "2a01::10:5", optially with port appended, eg "1.2.3.4:6666" or "[2a01::10:5]:6666"
+ * @af will contain either AF_INET or AF_INET6
+ * @addr will contain the address in network representation
+ * @port will contain the port in network representation, defaulting to #define PORT if none was given
+ * returns 1 on success, 0 in failure. contents of af, addr and port are undefined in the latter case
+ * !! Contents of @string might be modified by this function !!
+ */
+char parse_address(char *string, dnbd3_host_t *host)
+{
+	struct in_addr v4;
+	struct in6_addr v6;
+
+	// Try IPv4 without port
+	if (1 == inet_pton(AF_INET, string, &v4))
+	{
+		host->type = AF_INET;
+		memcpy(host->addr, &v4, 4);
+		host->port = htons(PORT);
+		return 1;
+	}
+	// Try IPv6 without port
+	if (1 == inet_pton(AF_INET6, string, &v6))
+	{
+		host->type = AF_INET6;
+		memcpy(host->addr, &v6, 16);
+		host->port = htons(PORT);
+		return 1;
+	}
+
+	// Scan for port
+	char *portpos = NULL, *ptr = string;
+	while (*ptr)
+	{
+		if (*ptr == ':')
+			portpos = ptr;
+		++ptr;
+	}
+	if (portpos == NULL)
+		return 0; // No port in string
+	// Consider IP being surrounded by [ ]
+	if (*string == '[' && *(portpos - 1) == ']')
+	{
+		++string;
+		*(portpos - 1) = '\0';
+	}
+	*portpos++ = '\0';
+	int p = atoi(portpos);
+	if (p < 1 || p > 65535)
+		return 0; // Invalid port
+	host->port = htons((uint16_t)p);
+
+	// Try IPv4 with port
+	if (1 == inet_pton(AF_INET, string, &v4))
+	{
+		host->type = AF_INET;
+		memcpy(host->addr, &v4, 4);
+		return 1;
+	}
+	// Try IPv6 with port
+	if (1 == inet_pton(AF_INET6, string, &v6))
+	{
+		host->type = AF_INET6;
+		memcpy(host->addr, &v6, 16);
+		return 1;
+	}
+
+	// FAIL
+	return 0;
+}
+
+/**
+ * Convert a host and port (network byte order) to printable representation.
+ * Worst case required buffer len is 48, eg. [1234:1234:1234:1234:1234:1234:1234:1234]:12345 (+ \0)
+ * Returns TRUE on success, FALSE on error
+ */
+char host_to_string(const dnbd3_host_t *host, char *target, size_t targetlen)
+{
+	// Worst case: Port 5 chars, ':' to separate ip and port 1 char, terminating null 1 char = 7, [] for IPv6
+	if (targetlen < 10)
+		return FALSE;
+	if (host->type == AF_INET6)
+	{
+		*target++ = '[';
+		inet_ntop(AF_INET6, host->addr, target, targetlen - 9);
+		target += strlen(target);
+		*target++ = ']';
+	}
+	else if (host->type == AF_INET)
+	{
+		inet_ntop(AF_INET, host->addr, target, targetlen - 7);
+		target += strlen(target);
+	}
+	else
+	{
+		snprintf(target, targetlen, "<?addrtype=%d>", (int)host->type);
+		return FALSE;
+	}
+	*target = '\0';
+	if (host->port != 0)
+	{
+		// There are still at least 7 bytes left in the buffer, port is at most 5 bytes + ':' + '\0' = 7
+		snprintf(target, 7, ":%d", (int)ntohs(host->port));
+	}
+	return TRUE;
+}
+
+char is_valid_namespace(char *namespace)
+{
+	if (*namespace == '\0' || *namespace == '/')
+		return 0; // Invalid: Length = 0 or starting with a slash
+	while (*namespace)
+	{
+		if (*namespace != '/' && *namespace != '-' && (*namespace < 'a' || *namespace > 'z')
+		        && (*namespace < 'A' || *namespace > 'Z')
+		        && (*namespace < '0' || *namespace > '9'))
+			return 0;
+		++namespace;
+	}
+	if (strstr(namespace, "//") != NULL)
+		return 0; // Invalid: Double slash
+	if (*(namespace - 1) == '/')
+		return 0; // Invalid: Ends in a slash
+	return 1;
+}
+
+char is_valid_imagename(char *namespace)
+{
+	if (*namespace == '\0' || *namespace == ' ')
+		return 0; // Invalid: Length = 0 or starting with a space
+	while (*namespace)
+	{
+		// Check for invalid chars
+		if (*namespace != '.' && *namespace != '-' && *namespace != ' '
+		        && *namespace != '(' && *namespace != ')'
+		        && (*namespace < 'a' || *namespace > 'z') && (*namespace < 'A' || *namespace > 'Z')
+		        && (*namespace < '0' || *namespace > '9'))
+			return 0;
+		++namespace;
+	}
+	if (*(namespace - 1) == ' ')
+		return 0; // Invalid: Ends in a space
+	return 1;
+}
+
+void strtolower(char *string)
+{
+	while (*string)
+	{
+		if (*string >= 'A' && *string <= 'Z')
+			*string += 32;
+		++string;
+	}
+}