diff options
Diffstat (limited to 'src/libsystemd-network/src/dhcp-identifier.c')
| -rw-r--r-- | src/libsystemd-network/src/dhcp-identifier.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/src/libsystemd-network/src/dhcp-identifier.c b/src/libsystemd-network/src/dhcp-identifier.c new file mode 100644 index 0000000000..afe0b9a404 --- /dev/null +++ b/src/libsystemd-network/src/dhcp-identifier.c @@ -0,0 +1,129 @@ +/*** + 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 <libudev.h> +#include <systemd/sd-id128.h> + +#include "systemd-basic/siphash24.h" +#include "systemd-basic/sparse-endian.h" +#include "systemd-basic/virt.h" +#include "systemd-network/dhcp-identifier.h" +#include "systemd-network/dhcp6-protocol.h" +#include "systemd-network/network-internal.h" +#include "systemd-shared/udev-util.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_validate_duid_len(uint16_t duid_type, size_t duid_len) { + struct duid d; + + assert_cc(sizeof(d.raw) >= MAX_DUID_LEN); + if (duid_len > MAX_DUID_LEN) + return -EINVAL; + + switch (duid_type) { + case DUID_TYPE_LLT: + if (duid_len <= sizeof(d.llt)) + return -EINVAL; + break; + case DUID_TYPE_EN: + if (duid_len != sizeof(d.en)) + return -EINVAL; + break; + case DUID_TYPE_LL: + if (duid_len <= sizeof(d.ll)) + return -EINVAL; + break; + case DUID_TYPE_UUID: + if (duid_len != sizeof(d.uuid)) + return -EINVAL; + break; + default: + /* accept unknown type in order to be forward compatible */ + break; + } + return 0; +} + +int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len) { + sd_id128_t machine_id; + uint64_t hash; + int r; + + assert(duid); + assert(len); + + r = sd_id128_get_machine(&machine_id); + if (r < 0) + return r; + + unaligned_write_be16(&duid->type, DUID_TYPE_EN); + unaligned_write_be32(&duid->en.pen, SYSTEMD_PEN); + + *len = sizeof(duid->type) + sizeof(duid->en); + + /* a bit of snake-oil perhaps, but no need to expose the machine-id + directly; duid->en.id might not be aligned, so we need to copy */ + hash = htole64(siphash24(&machine_id, sizeof(machine_id), HASH_KEY.bytes)); + memcpy(duid->en.id, &hash, sizeof(duid->en.id)); + + return 0; +} + +int dhcp_identifier_set_iaid(int ifindex, uint8_t *mac, size_t mac_len, void *_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() <= 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) { + if (udev_device_get_is_initialized(device) <= 0) + /* not yet ready */ + return -EBUSY; + + name = net_get_name(device); + } + } + + if (name) + id = siphash24(name, strlen(name), HASH_KEY.bytes); + else + /* fall back to MAC address if no predictable name available */ + id = siphash24(mac, mac_len, HASH_KEY.bytes); + + id = htole64(id); + + /* fold into 32 bits */ + unaligned_write_be32(_id, (id & 0xffffffff) ^ (id >> 32)); + + return 0; +} |