From: Tom Gundersen Date: Tue, 15 Jul 2014 15:57:43 +0000 (+0200) Subject: udev: link_setup - respect kernel name assign policy X-Git-Tag: v216~227 X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=04b67d49254d956d31bcfe80340fb9df7ed332d3;ds=inline udev: link_setup - respect kernel name assign policy Newer kernels export meta-information about the origin of an ifname. Respect this from the ifname rename logic. We do not rename any interfaces that was originally named by userspace, nor once which have already been renamed from userspace. Moreover, we optionally do not (the default) rename interfaces which the kernel claims to have named in a predictable way. --- diff --git a/man/systemd.link.xml b/man/systemd.link.xml index 05effc3b7..6075b39b7 100644 --- a/man/systemd.link.xml +++ b/man/systemd.link.xml @@ -236,10 +236,20 @@ not set directly, but is exported to udev as the property ID_NET_NAME, which is, by default, used by a udev rule to set - NAME. The available policies - are: + NAME. If the name has already + been set by userspace, no renaming is performed. + The available policies are: + + kernel + + If the kernel claims that the name it + has set for a device is predictable, then + no renaming is performed. + + + database diff --git a/network/99-default.link b/network/99-default.link index 53215f633..79538f9b2 100644 --- a/network/99-default.link +++ b/network/99-default.link @@ -1,3 +1,3 @@ [Link] -NamePolicy=database onboard slot path +NamePolicy=kernel database onboard slot path MACAddressPolicy=persistent diff --git a/src/shared/missing.h b/src/shared/missing.h index e20f9bdfd..195edfc67 100644 --- a/src/shared/missing.h +++ b/src/shared/missing.h @@ -525,3 +525,23 @@ static inline int setns(int fd, int nstype) { #ifndef BOND_XMIT_POLICY_ENCAP34 #define BOND_XMIT_POLICY_ENCAP34 4 #endif + +#ifndef NET_ADDR_RANDOM +# define NET_ADDR_RANDOM 1 +#endif + +#ifndef NET_NAME_ENUM +# define NET_NAME_ENUM 1 +#endif + +#ifndef NET_NAME_PREDICTABLE +# define NET_NAME_PREDICTABLE 2 +#endif + +#ifndef NET_NAME_USER +# define NET_NAME_USER 3 +#endif + +#ifndef NET_NAME_RENAMED +# define NET_NAME_RENAMED 4 +#endif diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c index 946715ce5..b44aeaf6d 100644 --- a/src/udev/net/link-config.c +++ b/src/udev/net/link-config.c @@ -20,10 +20,11 @@ ***/ #include -#include +#include #include "sd-id128.h" +#include "missing.h" #include "link-config.h" #include "ethtool-util.h" @@ -283,8 +284,33 @@ static bool mac_is_random(struct udev_device *device) { if (r < 0) return false; - /* check for NET_ADDR_RANDOM */ - return type == 1; + return type == NET_ADDR_RANDOM; +} + +static bool should_rename(struct udev_device *device, bool respect_predictable) { + const char *s; + unsigned type; + int r; + + s = udev_device_get_sysattr_value(device, "name_assign_type"); + if (!s) + return true; /* if we don't know, assume we should rename */ + r = safe_atou(s, &type); + if (r < 0) + return true; + + switch (type) { + case NET_NAME_USER: + case NET_NAME_RENAMED: + return false; /* these were already named by userspace, do not touch again */ + case NET_NAME_PREDICTABLE: + if (respect_predictable) + return false; /* the kernel claims to have given a predictable name */ + /* fall through */ + case NET_NAME_ENUM: + default: + return true; /* the name is known to be bad, or of an unknown type */ + } } static int get_mac(struct udev_device *device, bool want_random, struct ether_addr *mac) { @@ -315,6 +341,7 @@ int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_dev const char *new_name = NULL; struct ether_addr generated_mac; struct ether_addr *mac = NULL; + bool respect_predictable = false; int r, ifindex; assert(ctx); @@ -350,8 +377,12 @@ int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_dev if (ctx->enable_name_policy && config->name_policy) { NamePolicy *policy; - for (policy = config->name_policy; !new_name && *policy != _NAMEPOLICY_INVALID; policy++) { + for (policy = config->name_policy; !respect_predictable && !new_name && + *policy != _NAMEPOLICY_INVALID; policy++) { switch (*policy) { + case NAMEPOLICY_KERNEL: + respect_predictable = true; + break; case NAMEPOLICY_DATABASE: new_name = udev_device_get_property_value(device, "ID_NET_NAME_FROM_DATABASE"); break; @@ -373,12 +404,14 @@ int link_config_apply(link_config_ctx *ctx, link_config *config, struct udev_dev } } - if (new_name) - *name = new_name; /* a name was set by a policy */ - else if (config->name) - *name = config->name; /* a name was set manually in the config */ - else - *name = NULL; + if (should_rename(device, respect_predictable)) { + if (!new_name) + /* if not set by policy, fall back manually set name */ + new_name = config->name; + } else + new_name = NULL; + + *name = new_name; switch (config->mac_policy) { case MACPOLICY_PERSISTENT: @@ -444,6 +477,7 @@ DEFINE_STRING_TABLE_LOOKUP(mac_policy, MACPolicy); DEFINE_CONFIG_PARSE_ENUM(config_parse_mac_policy, mac_policy, MACPolicy, "Failed to parse MAC address policy"); static const char* const name_policy_table[_NAMEPOLICY_MAX] = { + [NAMEPOLICY_KERNEL] = "kernel", [NAMEPOLICY_DATABASE] = "database", [NAMEPOLICY_ONBOARD] = "onboard", [NAMEPOLICY_SLOT] = "slot", diff --git a/src/udev/net/link-config.h b/src/udev/net/link-config.h index 24fdb87e4..5f3d4ad14 100644 --- a/src/udev/net/link-config.h +++ b/src/udev/net/link-config.h @@ -39,6 +39,7 @@ typedef enum MACPolicy { } MACPolicy; typedef enum NamePolicy { + NAMEPOLICY_KERNEL, NAMEPOLICY_DATABASE, NAMEPOLICY_ONBOARD, NAMEPOLICY_SLOT,