From 16b9b87aeee9353b5b8dae6089a69752422a5b09 Mon Sep 17 00:00:00 2001 From: Tom Gundersen Date: Mon, 28 Oct 2013 00:19:59 +0100 Subject: [PATCH] udev: link-config - add mac address policy This introduces a new key MACAddressPolicy. The possible policies are 'persistent' and 'random'. 'persistent' will do nothing if the current address is the hardware address, but if the hardware does not have an address (or another address is set for whatever reason), we will generate an address which will be random, but persistent between boots (based on machineid and persistent netif name). 'random' will do nothing if the kernel already set a random address, otherwise it will generate a random one and use that instead. This patch sets MACAddressPolicy=persistent in the default .link file. --- Makefile.am | 1 + links/99-default.link | 1 + src/udev/net/link-config-gperf.gperf | 1 + src/udev/net/link-config.c | 174 ++++++++++++++++++++++----- src/udev/net/link-config.h | 1 + 5 files changed, 150 insertions(+), 28 deletions(-) diff --git a/Makefile.am b/Makefile.am index 4a96a5005..2acd22bef 100644 --- a/Makefile.am +++ b/Makefile.am @@ -2347,6 +2347,7 @@ libudev_core_la_LIBADD = \ libsystemd-daemon-internal.la \ libsystemd-shared.la \ libsystemd-rtnl.la \ + libsystemd-id128.la \ $(BLKID_LIBS) \ $(KMOD_LIBS) diff --git a/links/99-default.link b/links/99-default.link index c5043b857..05be03bd3 100644 --- a/links/99-default.link +++ b/links/99-default.link @@ -1,2 +1,3 @@ [Link] NamePolicy=onboard slot path +MACAddressPolicy=persistent diff --git a/src/udev/net/link-config-gperf.gperf b/src/udev/net/link-config-gperf.gperf index b38dbe80b..1d905319e 100644 --- a/src/udev/net/link-config-gperf.gperf +++ b/src/udev/net/link-config-gperf.gperf @@ -19,6 +19,7 @@ Match.Path, config_parse_string, 0, offsetof(link Match.Driver, config_parse_string, 0, offsetof(link_config, match_driver) Match.Type, config_parse_string, 0, offsetof(link_config, match_type) Link.Description, config_parse_string, 0, offsetof(link_config, description) +Link.MACAddressPolicy, config_parse_string, 0, offsetof(link_config, mac_policy) Link.MACAddress, config_parse_string, 0, offsetof(link_config, mac) Link.NamePolicy, config_parse_strv, 0, offsetof(link_config, name_policy) Link.Name, config_parse_string, 0, offsetof(link_config, name) diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c index 9c75b62b7..089bd7656 100644 --- a/src/udev/net/link-config.c +++ b/src/udev/net/link-config.c @@ -22,8 +22,9 @@ #include #include -#include "link-config.h" +#include "sd-id128.h" +#include "link-config.h" #include "ethtool-util.h" #include "libudev-private.h" @@ -35,6 +36,7 @@ #include "conf-parser.h" #include "conf-files.h" #include "fileio.h" +#include "hashmap.h" struct link_config_ctx { LIST_HEAD(link_config, links); @@ -252,11 +254,9 @@ int link_config_get(link_config_ctx *ctx, struct udev_device *device, link_confi return -ENOENT; } -static int rtnl_set_properties(sd_rtnl *rtnl, int ifindex, const char *name, const char *mac, unsigned int mtu) { +static int rtnl_set_properties(sd_rtnl *rtnl, int ifindex, const char *name, const struct ether_addr *mac, unsigned int mtu) { _cleanup_sd_rtnl_message_unref_ sd_rtnl_message *message; - char new_name[IFNAMSIZ]; - struct ether_addr new_mac; - bool need_update; + bool need_update = false; int r; assert(rtnl); @@ -267,8 +267,7 @@ static int rtnl_set_properties(sd_rtnl *rtnl, int ifindex, const char *name, con return r; if (name) { - strscpy(new_name, IFNAMSIZ, name); - r = sd_rtnl_message_append(message, IFLA_IFNAME, new_name); + r = sd_rtnl_message_append(message, IFLA_IFNAME, name); if (r < 0) return r; @@ -276,16 +275,7 @@ static int rtnl_set_properties(sd_rtnl *rtnl, int ifindex, const char *name, con } if (mac) { - r = sscanf(mac, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx", - &new_mac.ether_addr_octet[0], - &new_mac.ether_addr_octet[1], - &new_mac.ether_addr_octet[2], - &new_mac.ether_addr_octet[3], - &new_mac.ether_addr_octet[4], - &new_mac.ether_addr_octet[5]); - if (r != 6) - return -EINVAL; - r = sd_rtnl_message_append(message, IFLA_ADDRESS, &new_mac); + r = sd_rtnl_message_append(message, IFLA_ADDRESS, mac); if (r < 0) return r; @@ -301,7 +291,7 @@ static int rtnl_set_properties(sd_rtnl *rtnl, int ifindex, const char *name, con } if (need_update) { - r = sd_rtnl_send_with_reply_and_block(rtnl, message, 250 * USEC_PER_MSEC, NULL); + r = sd_rtnl_send_with_reply_and_block(rtnl, message, 5 * USEC_PER_SEC, NULL); if (r < 0) return r; } @@ -328,8 +318,90 @@ static bool enable_name_policy(void) { return true; } +static bool mac_is_random(struct udev_device *device) { + const char *s; + int type; + + s = udev_device_get_sysattr_value(device, "addr_assign_type"); + if (!s) + return -EINVAL; + type = strtoul(s, NULL, 0); + + /* check for NET_ADDR_RANDOM */ + return type == 1; +} + +static bool mac_is_permanent(struct udev_device *device) { + const char *s; + int type; + + s = udev_device_get_sysattr_value(device, "addr_assign_type"); + if (!s) + return -EINVAL; + type = strtoul(s, NULL, 0); + + /* check for NET_ADDR_PERM */ + return type == 0; +} + +static int get_mac(struct udev_device *device, bool want_random, struct ether_addr **ret) { + struct ether_addr *mac; + unsigned int seed; + int r, i; + + mac = calloc(1, sizeof(struct ether_addr)); + if (!mac) + return -ENOMEM; + + if (want_random) + seed = random_u(); + else { + const char *name; + sd_id128_t machine; + char machineid_buf[33]; + const char *seed_str; + + /* fetch some persistent data unique (on this machine) to this device */ + name = udev_device_get_property_value(device, "ID_NET_NAME_ONBOARD"); + if (!name) { + name = udev_device_get_property_value(device, "ID_NET_NAME_SLOT"); + if (!name) { + name = udev_device_get_property_value(device, "ID_NET_NAME_PATH"); + if (!name) + return -1; + } + } + /* fetch some persistent data unique to this machine */ + r = sd_id128_get_machine(&machine); + if (r < 0) + return -1; + + /* combine the data */ + seed_str = strappenda(name, sd_id128_to_string(machine, machineid_buf)); + + /* hash to get seed */ + seed = string_hash_func(seed_str); + } + + srandom(seed); + + for(i = 0; i < ETH_ALEN; i++) { + mac->ether_addr_octet[i] = random(); + } + + /* see eth_random_addr in the kernel */ + mac->ether_addr_octet[0] &= 0xfe; /* clear multicast bit */ + mac->ether_addr_octet[0] |= 0x02; /* set local assignment bit (IEEE802) */ + + *ret = mac; + + return 0; +} + int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_device *device) { - const char *name, *new_name = NULL; + const char *name; + char *new_name = NULL; + struct ether_addr *mac = NULL; int r, ifindex; name = udev_device_get_sysname(device); @@ -380,19 +452,27 @@ int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_dev STRV_FOREACH(policy, config->name_policy) { if (streq(*policy, "onboard")) { - new_name = udev_device_get_property_value(device, "ID_NET_NAME_ONBOARD"); + r = strdup_or_null(udev_device_get_property_value(device, "ID_NET_NAME_ONBOARD"), &new_name); + if (r < 0) + return r; if (new_name) break; } else if (streq(*policy, "slot")) { - new_name = udev_device_get_property_value(device, "ID_NET_NAME_SLOT"); + r = strdup_or_null(udev_device_get_property_value(device, "ID_NET_NAME_SLOT"), &new_name); + if (r < 0) + return r; if (new_name) break; } else if (streq(*policy, "path")) { - new_name = udev_device_get_property_value(device, "ID_NET_NAME_PATH"); + r = strdup_or_null(udev_device_get_property_value(device, "ID_NET_NAME_PATH"), &new_name); + if (r < 0) + return r; if (new_name) break; } else if (streq(*policy, "mac")) { - new_name = udev_device_get_property_value(device, "ID_NET_NAME_MAC"); + r = strdup_or_null(udev_device_get_property_value(device, "ID_NET_NAME_MAC"), &new_name); + if (r < 0) + return r; if (new_name) break; } else @@ -400,14 +480,52 @@ int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_dev } } - if (!new_name && config->name) - new_name = config->name; + if (!new_name && config->name) { + new_name = calloc(1, IFNAMSIZ); + strscpy(new_name, IFNAMSIZ, config->name); + } - r = rtnl_set_properties(ctx->rtnl, ifindex, new_name, config->mac, config->mtu); + if (config->mac_policy) { + if (streq(config->mac_policy, "persistent")) { + if (!mac_is_permanent(device)) { + r = get_mac(device, false, &mac); + if (r < 0) + return r; + } + } else if (streq(config->mac_policy, "random")) { + if (!mac_is_random(device)) { + r = get_mac(device, true, &mac); + if (r < 0) + return r; + } + } else + log_warning("Invalid MACAddress policy '%s', ignoring.", config->mac_policy); + } + + if (!mac && config->mac) { + mac = calloc(1, sizeof(struct ether_addr)); + r = sscanf(config->mac, "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx", + &mac->ether_addr_octet[0], + &mac->ether_addr_octet[1], + &mac->ether_addr_octet[2], + &mac->ether_addr_octet[3], + &mac->ether_addr_octet[4], + &mac->ether_addr_octet[5]); + if (r != 6) { + r = -EINVAL; + goto out; + } + } + + r = rtnl_set_properties(ctx->rtnl, ifindex, new_name, mac, config->mtu); if (r < 0) { - log_warning("Could not set Name, MACAddress or MTU on %s", name); - return r; + log_warning("Could not set Name, MACAddress or MTU on %s: %s", name, strerror(-r)); + goto out; } return 0; +out: + free(new_name); + free(mac); + return r; } diff --git a/src/udev/net/link-config.h b/src/udev/net/link-config.h index 0f57dc9cb..d0a81f8bc 100644 --- a/src/udev/net/link-config.h +++ b/src/udev/net/link-config.h @@ -39,6 +39,7 @@ struct link_config { char *description; char *mac; + char *mac_policy; char **name_policy; char *name; unsigned int mtu; -- 2.30.2