network: dhcp - split out dhcp_identifier_set_{iaid,duid_en} from dhcp6-client

This will also be used in dhcp4-client.

1 files changed, 101 insertions, 0 deletions

diff --git a/src/libsystemd-network/dhcp-identifier.c b/src/libsystemd-network/dhcp-identifier.c
new file mode 100644
index 0000000000..5386dca9e2
--- /dev/null
+++ b/src/libsystemd-network/dhcp-identifier.c
@@ -0,0 +1,101 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright (C) 2015 Tom Gundersen <teg@jklmen>
+
+  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 <net/ethernet.h>
+
+#include "sd-id128.h"
+#include "libudev.h"
+#include "udev-util.h"
+
+#include "virt.h"
+#include "sparse-endian.h"
+#include "siphash24.h"
+#include "util.h"
+
+#include "dhcp6-protocol.h"
+#include "dhcp-identifier.h"
+#include "network-internal.h"
+
+#define SYSTEMD_PEN 43793
+#define HASH_KEY SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
+
+int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len) {
+        sd_id128_t machine_id;
+        int r;
+
+        assert(duid);
+        assert(len);
+
+        r = sd_id128_get_machine(&machine_id);
+        if (r < 0)
+                return r;
+
+        duid->type = htobe16(DHCP6_DUID_EN);
+        duid->en.pen = htobe32(SYSTEMD_PEN);
+        *len = sizeof(duid->type) + sizeof(duid->en);
+
+        /* a bit of snake-oil perhaps, but no need to expose the machine-id
+           directly */
+        siphash24(duid->en.id, &machine_id, sizeof(machine_id), HASH_KEY.bytes);
+
+        return 0;
+}
+
+
+int dhcp_identifier_set_iaid(int ifindex, uint8_t *mac, size_t mac_len, uint32_t *_id) {
+        /* name is a pointer to memory in the udev_device struct, so must
+           have the same scope */
+        _cleanup_udev_device_unref_ struct udev_device *device = NULL;
+        const char *name = NULL;
+        uint64_t id;
+
+        if (detect_container(NULL) <= 0) {
+                /* not in a container, udev will be around */
+                _cleanup_udev_unref_ struct udev *udev;
+                char ifindex_str[2 + DECIMAL_STR_MAX(int)];
+
+                udev = udev_new();
+                if (!udev)
+                        return -ENOMEM;
+
+                sprintf(ifindex_str, "n%d", ifindex);
+                device = udev_device_new_from_device_id(udev, ifindex_str);
+                if (!device)
+                        return -errno;
+
+                if (udev_device_get_is_initialized(device) <= 0)
+                        /* not yet ready */
+                        return -EBUSY;
+
+                name = net_get_name(device);
+        }
+
+        if (name)
+                siphash24((uint8_t*)&id, name, strlen(name), HASH_KEY.bytes);
+        else
+                /* fall back to mac address if no predictable name available */
+                siphash24((uint8_t*)&id, mac, mac_len, HASH_KEY.bytes);
+
+        /* fold into 32 bits */
+        *_id = (id & 0xffffffff) ^ (id >> 32);
+
+        return 0;
+}