sys/posix: add module posix_netdb

sys/Makefile

@@ -161,6 +161,9 @@ endif
 ifneq (,$(filter posix_inet,$(USEMODULE)))
   DIRS += posix/inet
 endif
+ifneq (,$(filter posix_netdb,$(USEMODULE)))
+  DIRS += posix/netdb
+endif
 ifneq (,$(filter posix_select,$(USEMODULE)))
   DIRS += posix/select
 endif

sys/Makefile.dep

@@ -335,6 +335,11 @@ ifneq (,$(filter posix_sleep,$(USEMODULE)))
   USEMODULE += posix_headers
 endif
 
+ifneq (,$(filter posix_netdb,$(USEMODULE)))
+  USEMODULE += posix_inet
+  USEMODULE += sock_dns
+endif
+
 ifneq (,$(filter posix_inet,$(USEMODULE)))
   USEMODULE += posix_headers
 endif

sys/posix/include/netdb.h

@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2021 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup posix
+ *
+ * @{
+ * @file
+ * @brief  posix netdb implementation
+ * @author Hendrik van Essen <hendrik.ve@fu-berlin.de>
+ */
+
+#ifndef NETDB_H
+#define NETDB_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "sys/bytes.h"
+
+/** Errors used by the DNS API functions */
+/**
+ * @brief The name could not be resolved at this time. Future attempts may succeed.
+ */
+#define EAI_AGAIN       1
+/**
+ * @brief The flags parameter had an invalid value.
+ */
+#define EAI_BADFLAGS    2
+/**
+ * @brief A non-recoverable error occurred when attempting to resolve the name.
+ */
+#define EAI_FAIL        3
+/**
+ * @brief The address family was not recognized.
+ */
+#define EAI_FAMILY      4
+/**
+ * @brief There was a memory allocation failure when trying to allocate storage
+ *        for the return value.
+ */
+#define EAI_MEMORY      5
+/**
+ * @brief The name does not resolve for the supplied parameters. Neither
+ *        nodename nor servname were supplied. At least one of these need to
+ *        be supplied.
+ */
+#define EAI_NONAME      6
+/**
+ * @brief The service passed was not recognized for the specified socket type.
+ */
+#define EAI_SERVICE     7
+/**
+ * @brief The intended socket type was not recognized.
+ */
+#define EAI_SOCKTYPE    8
+/**
+ * @brief A system error occurred.
+ */
+#define EAI_SYSTEM      9
+
+/* Input flags for struct addrinfo */
+/**
+ * @brief Returned address information shall be suitable for use in binding a
+ *        socket for accepting incoming connections for the specified service.
+ */
+#define AI_PASSIVE      0x01
+/**
+ * @brief Determine the canonical name corresponding to nodename.
+ */
+#define AI_CANONNAME    0x02
+/**
+ * @brief Supplied nodename string is a numeric host address string.
+ */
+#define AI_NUMERICHOST  0x04
+/**
+ * @brief Supplied servname string is a numeric port string.
+ */
+#define AI_NUMERICSERV  0x08
+/**
+ * @brief When specified along with ai_family = AF_INET6, getaddrinfo() returns
+ *        IPv4-mapped IPv6 addresses on finding no matching IPv6 addresses.
+ *
+ * @note: Not supported yet
+ * @todo: Implement
+ */
+#define AI_V4MAPPED     0x10
+/**
+ * @brief When AI_V4MAPPED is specified, then getaddrinfo() returns all matching
+ *        IPv6 and IPv4 addresses. Without AI_V4MAPPED this flag will be ignored.
+ *
+ * @note: Not supported yet
+ * @todo: Implement
+ */
+#define AI_ALL          0x20
+/**
+ * @brief IPv4 addresses are returned only if an IPv4 address is configured on
+ *        the local system, and IPv6 addresses are returned only if an IPv6
+ *        address is configured on the local system.
+ *
+ * @note: Not supported yet
+ * @todo: Implement
+ */
+#define AI_ADDRCONFIG   0x40
+
+/**
+ * @brief Structure that contains information about the address of a service provider
+ */
+struct addrinfo {
+    int               ai_flags;      /**< Input flags. */
+    int               ai_family;     /**< Address family of socket. */
+    int               ai_socktype;   /**< Socket type. */
+    int               ai_protocol;   /**< Protocol of socket. */
+    socklen_t         ai_addrlen;    /**< Length of socket address. */
+    struct sockaddr  *ai_addr;       /**< Socket address of socket. */
+    char             *ai_canonname;  /**< Canonical name of service location. */
+    struct addrinfo  *ai_next;       /**< Pointer to next in list. */
+};
+
+/**
+ *
+ * @brief Free the addrinfo reference returned by getaddrinfo()
+ *
+ * Frees one or more addrinfo structures returned by getaddrinfo(), along with
+ * any additional storage associated with those structures. If the ai_next field
+ * of the structure is not null, the entire list of structures is freed.
+ *
+ * @param ai struct addrinfo to free
+ */
+void freeaddrinfo(struct addrinfo *ai);
+
+/**
+ *
+ * @brief Translates the name of a service location and/or a service name and
+ *        returns a set of socket addresses.
+ *
+ * @note  Due to implementation limitations only a single entry is returned.
+ *
+ * Translates the name of a service location (for example, a host name) and/or
+ * a service name and returns a set of socket addresses and associated
+ * information to be used in creating a socket with which to address the
+ * specified service.
+ * Memory for the result is allocated internally and must be freed by calling
+ * freeaddrinfo()!
+ *
+ * @param nodename      descriptive name or address string of the host (may be
+ *                      NULL -> local address)
+ * @param servname      port number as string of NULL
+ * @param hints         structure containing input values that set socktype and
+ *                      protocol
+ * @param res           pointer to a pointer where to store the result (is set
+ *                      to NULL in case of failure)
+ *
+ * @return 0            On success, non-zero on failure
+ * @retval EAI_AGAIN    Recoverable error, try again later
+ * @retval EAI_BADFLAGS Invalid value in flag parameters (hints->ai_flags)
+ * @retval EAI_FAIL     Non-recoverable error
+ * @retval EAI_FAMILY   Unsupported address family
+ * @retval EAI_MEMORY   No memory available to receive data or to allocate result object
+ * @retval EAI_NONAME   Name does not resolve
+ * @retval EAI_SERVICE  Service does not resolve
+ */
+int getaddrinfo(const char *nodename, const char *servname,
+                const struct addrinfo *hints, struct addrinfo **res);
+
+#ifdef __cplusplus
+}
+#endif
+
+/**
+ * @}
+ */
+#endif /* NETDB_H */

sys/posix/netdb/Makefile

@@ -0,0 +1,3 @@
+MODULE = posix_netdb
+
+include $(RIOTBASE)/Makefile.base