sd-network: add new library

[elogind.git] / src / libsystemd-network / dhcp-option.c

diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c
new file mode 100644 (file)
index 0000000..4d45b3b
--- /dev/null
+++ b/src/libsystemd-network/dhcp-option.c
@@ -0,0 +1,184 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  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 <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <stdio.h>
+
+#include "dhcp-internal.h"
+
+int dhcp_option_append(uint8_t **buf, size_t *buflen, uint8_t code,
+                       size_t optlen, const void *optval)
+{
+        if (!buf || !buflen)
+                return -EINVAL;
+
+        switch (code) {
+
+        case DHCP_OPTION_PAD:
+        case DHCP_OPTION_END:
+                if (*buflen < 1)
+                        return -ENOBUFS;
+
+                (*buf)[0] = code;
+                *buf += 1;
+                *buflen -= 1;
+                break;
+
+        default:
+                if (*buflen < optlen + 2)
+                        return -ENOBUFS;
+
+                if (!optval)
+                        return -EINVAL;
+
+                (*buf)[0] = code;
+                (*buf)[1] = optlen;
+                memcpy(&(*buf)[2], optval, optlen);
+
+                *buf += optlen + 2;
+                *buflen -= (optlen + 2);
+
+                break;
+        }
+
+        return 0;
+}
+
+static int parse_options(const uint8_t *buf, size_t buflen, uint8_t *overload,
+                         uint8_t *message_type, dhcp_option_cb_t cb,
+                         void *user_data)
+{
+        const uint8_t *code = buf;
+        const uint8_t *len;
+
+        while (buflen > 0) {
+                switch (*code) {
+                case DHCP_OPTION_PAD:
+                        buflen -= 1;
+                        code++;
+                        break;
+
+                case DHCP_OPTION_END:
+                        return 0;
+
+                case DHCP_OPTION_MESSAGE_TYPE:
+                        if (buflen < 3)
+                                return -ENOBUFS;
+                        buflen -= 3;
+
+                        len = code + 1;
+                        if (*len != 1)
+                                return -EINVAL;
+
+                        if (message_type)
+                                *message_type = *(len + 1);
+
+                        code += 3;
+
+                        break;
+
+                case DHCP_OPTION_OVERLOAD:
+                        if (buflen < 3)
+                                return -ENOBUFS;
+                        buflen -= 3;
+
+                        len = code + 1;
+                        if (*len != 1)
+                                return -EINVAL;
+
+                        if (overload)
+                                *overload = *(len + 1);
+
+                        code += 3;
+
+                        break;
+
+                default:
+                        if (buflen < 3)
+                                return -ENOBUFS;
+
+                        len = code + 1;
+
+                        if (buflen < (size_t)*len + 2)
+                                return -EINVAL;
+                        buflen -= *len + 2;
+
+                        if (cb)
+                                cb(*code, *len, len + 1, user_data);
+
+                        code += *len + 2;
+
+                        break;
+                }
+        }
+
+        if (buflen)
+                return -EINVAL;
+
+        return 0;
+}
+
+int dhcp_option_parse(DHCPMessage *message, size_t len,
+                      dhcp_option_cb_t cb, void *user_data)
+{
+        uint8_t overload = 0;
+        uint8_t message_type = 0;
+        uint8_t *opt = (uint8_t *)(message + 1);
+        int res;
+
+        if (!message)
+                return -EINVAL;
+
+        if (len < sizeof(DHCPMessage) + 4)
+                return -EINVAL;
+
+        len -= sizeof(DHCPMessage) + 4;
+
+        if (opt[0] != 0x63 && opt[1] != 0x82 && opt[2] != 0x53 &&
+                        opt[3] != 0x63)
+                return -EINVAL;
+
+        res = parse_options(&opt[4], len, &overload, &message_type,
+                        cb, user_data);
+        if (res < 0)
+                return res;
+
+        if (overload & DHCP_OVERLOAD_FILE) {
+                res = parse_options(message->file, sizeof(message->file),
+                                NULL, &message_type, cb, user_data);
+                if (res < 0)
+                        return res;
+        }
+
+        if (overload & DHCP_OVERLOAD_SNAME) {
+                res = parse_options(message->sname, sizeof(message->sname),
+                                NULL, &message_type, cb, user_data);
+                if (res < 0)
+                        return res;
+        }
+
+        if (message_type)
+                return message_type;
+
+        return -ENOMSG;
+}