[systemd-devel] [PATCH v2 02/26] dhcp: Add DHCP client initialization

[Patrik Flykt]

Provide functionality for initializing a DHCP client struct, setting
interface index, last used address and additional options to request.
On initialization the most useful options are added by default.
---
v2: - public api with sd_ prefix into src/systemd/sd-dhcp-client.h
    - use assert_return when checking function arguments
    - use GREEDY_ALLOC, ELEMENTSOF
    - use uint32_t internally for IPv4 addresses
    - use in_addr in the external API for IPv4 addresses to be consistent
      with later DHCPv6 implementation

 src/dhcp/client.c            |  121 ++++++++++++++++++++++++++++++++++++++++++
 src/systemd/sd-dhcp-client.h |   33 ++++++++++++
 2 files changed, 154 insertions(+)
 create mode 100644 src/dhcp/client.c
 create mode 100644 src/systemd/sd-dhcp-client.h

diff --git a/src/dhcp/client.c b/src/dhcp/client.c
new file mode 100644
index 0000000..6e34ba9
--- /dev/null
+++ b/src/dhcp/client.c
@@ -0,0 +1,121 @@
+/***
+  This file is part of systemd.
+
+  Copyright (C) 2013 Intel Corporation. All rights reserved.
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "util.h"
+#include "list.h"
+
+#include "protocol.h"
+#include "sd-dhcp-client.h"
+
+struct DHCPClient {
+        DHCPState state;
+        int index;
+        uint8_t *req_opts;
+        size_t req_opts_size;
+        uint32_t last_addr;
+};
+
+static const uint8_t default_req_opts[] = {
+        DHCP_OPTION_SUBNET_MASK,
+        DHCP_OPTION_ROUTER,
+        DHCP_OPTION_HOST_NAME,
+        DHCP_OPTION_DOMAIN_NAME,
+        DHCP_OPTION_DOMAIN_NAME_SERVER,
+        DHCP_OPTION_NTP_SERVER,
+};
+
+int sd_dhcp_client_set_request_option(DHCPClient *client, const uint8_t option)
+{
+        size_t i;
+
+        assert_return(client, -EINVAL);
+        assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
+
+        switch(option) {
+        case DHCP_OPTION_PAD:
+        case DHCP_OPTION_OVERLOAD:
+        case DHCP_OPTION_MESSAGE_TYPE:
+        case DHCP_OPTION_PARAMETER_REQUEST_LIST:
+        case DHCP_OPTION_END:
+                return -EINVAL;
+
+        default:
+                break;
+        }
+
+        for (i = 0; i < client->req_opts_size; i++)
+                if (client->req_opts[i] == option)
+                        return -EEXIST;
+
+        if (!GREEDY_REALLOC(client->req_opts, client->req_opts_size,
+                            client->req_opts_size + 1))
+                return -ENOMEM;
+
+        client->req_opts[client->req_opts_size - 1] = option;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_request_address(DHCPClient *client,
+                                       const struct in_addr *last_addr)
+{
+        assert_return(client, -EINVAL);
+        assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
+
+        if (last_addr)
+                client->last_addr = last_addr->s_addr;
+        else
+                client->last_addr = INADDR_ANY;
+
+        return 0;
+}
+
+int sd_dhcp_client_set_index(DHCPClient *client, const int interface_index)
+{
+        assert_return(client, -EINVAL);
+        assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
+        assert_return(interface_index >= -1, -EINVAL);
+
+        client->index = interface_index;
+
+        return 0;
+}
+
+DHCPClient *sd_dhcp_client_new(void)
+{
+        DHCPClient *client;
+
+        client = new0(DHCPClient, 1);
+        if (!client)
+                return NULL;
+
+        client->state = DHCP_STATE_INIT;
+        client->index = -1;
+
+        client->req_opts_size = ELEMENTSOF(default_req_opts);
+
+        client->req_opts = memdup(default_req_opts, client->req_opts_size);
+
+        return client;
+}
diff --git a/src/systemd/sd-dhcp-client.h b/src/systemd/sd-dhcp-client.h
new file mode 100644
index 0000000..65caf59
--- /dev/null
+++ b/src/systemd/sd-dhcp-client.h
@@ -0,0 +1,33 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright (C) 2013 Intel Corporation. All rights reserved.
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <netinet/in.h>
+
+typedef struct DHCPClient DHCPClient;
+
+int sd_dhcp_client_set_request_option(DHCPClient *client, const uint8_t option);
+int sd_dhcp_client_set_request_address(DHCPClient *client,
+                                       const struct in_addr *last_address);
+int sd_dhcp_client_set_index(DHCPClient *client, const int interface_index);
+
+DHCPClient *sd_dhcp_client_new(void);
-- 
1.7.10.4