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net: dcb: Add priority-to-DSCP map getters

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On ingress, a network device such as a switch assigns to packets
priority based on various criteria. Common options include interpreting
PCP and DSCP fields according to user configuration. When a packet
egresses the switch, a reverse process may rewrite PCP and/or DSCP
values according to packet priority.

The following three functions support a) obtaining a DSCP-to-priority
map or vice versa, and b) finding default-priority entries in APP
database.

The DCB subsystem supports for APP entries a very generous M:N mapping
between priorities and protocol identifiers. Understandably,
several (say) DSCP values can map to the same priority. But this
asymmetry holds the other way around as well--one priority can map to
several DSCP values. For this reason, the following functions operate in
terms of bitmaps, with ones in positions that match some APP entry.

- dcb_ieee_getapp_dscp_prio_mask_map() to compute for a given netdevice
  a map of DSCP-to-priority-mask, which gives for each DSCP value a
  bitmap of priorities related to that DSCP value by APP, along the
  lines of dcb_ieee_getapp_mask().

- dcb_ieee_getapp_prio_dscp_mask_map() similarly to compute for a given
  netdevice a map from priorities to a bitmap of DSCPs.

- dcb_ieee_getapp_default_prio_mask() which finds all default-priority
  rules for a given port in APP database, and returns a mask of
  priorities allowed by these default-priority rules.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Petr Machata 2018-07-27 15:26:56 +03:00 committed by David S. Miller
parent 08193d1a89
commit b67c540b8a
2 changed files with 99 additions and 0 deletions
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13
include/net/dcbnl.h
View File

@ -34,6 +34,19 @@ int dcb_ieee_setapp(struct net_device *, struct dcb_app *);
int dcb_ieee_delapp(struct net_device *, struct dcb_app *);
u8 dcb_ieee_getapp_mask(struct net_device *, struct dcb_app *);
struct dcb_ieee_app_prio_map {
u64 map[IEEE_8021QAZ_MAX_TCS];
};
void dcb_ieee_getapp_prio_dscp_mask_map(const struct net_device *dev,
struct dcb_ieee_app_prio_map *p_map);
struct dcb_ieee_app_dscp_map {
u8 map[64];
};
void dcb_ieee_getapp_dscp_prio_mask_map(const struct net_device *dev,
struct dcb_ieee_app_dscp_map *p_map);
u8 dcb_ieee_getapp_default_prio_mask(const struct net_device *dev);
int dcbnl_ieee_notify(struct net_device *dev, int event, int cmd,
u32 seq, u32 pid);
int dcbnl_cee_notify(struct net_device *dev, int event, int cmd,

86
net/dcb/dcbnl.c
View File

@ -1958,6 +1958,92 @@ int dcb_ieee_delapp(struct net_device *dev, struct dcb_app *del)
}
EXPORT_SYMBOL(dcb_ieee_delapp);
/**
* dcb_ieee_getapp_prio_dscp_mask_map - For a given device, find mapping from
* priorities to the DSCP values assigned to that priority. Initialize p_map
* such that each map element holds a bit mask of DSCP values configured for
* that priority by APP entries.
*/
void dcb_ieee_getapp_prio_dscp_mask_map(const struct net_device *dev,
struct dcb_ieee_app_prio_map *p_map)
{
int ifindex = dev->ifindex;
struct dcb_app_type *itr;
u8 prio;
memset(p_map->map, 0, sizeof(p_map->map));
spin_lock_bh(&dcb_lock);
list_for_each_entry(itr, &dcb_app_list, list) {
if (itr->ifindex == ifindex &&
itr->app.selector == IEEE_8021QAZ_APP_SEL_DSCP &&
itr->app.protocol < 64 &&
itr->app.priority < IEEE_8021QAZ_MAX_TCS) {
prio = itr->app.priority;
p_map->map[prio] |= 1ULL << itr->app.protocol;
}
}
spin_unlock_bh(&dcb_lock);
}
EXPORT_SYMBOL(dcb_ieee_getapp_prio_dscp_mask_map);
/**
* dcb_ieee_getapp_dscp_prio_mask_map - For a given device, find mapping from
* DSCP values to the priorities assigned to that DSCP value. Initialize p_map
* such that each map element holds a bit mask of priorities configured for a
* given DSCP value by APP entries.
*/
void
dcb_ieee_getapp_dscp_prio_mask_map(const struct net_device *dev,
struct dcb_ieee_app_dscp_map *p_map)
{
int ifindex = dev->ifindex;
struct dcb_app_type *itr;
memset(p_map->map, 0, sizeof(p_map->map));
spin_lock_bh(&dcb_lock);
list_for_each_entry(itr, &dcb_app_list, list) {
if (itr->ifindex == ifindex &&
itr->app.selector == IEEE_8021QAZ_APP_SEL_DSCP &&
itr->app.protocol < 64 &&
itr->app.priority < IEEE_8021QAZ_MAX_TCS)
p_map->map[itr->app.protocol] |= 1 << itr->app.priority;
}
spin_unlock_bh(&dcb_lock);
}
EXPORT_SYMBOL(dcb_ieee_getapp_dscp_prio_mask_map);
/**
* Per 802.1Q-2014, the selector value of 1 is used for matching on Ethernet
* type, with valid PID values >= 1536. A special meaning is then assigned to
* protocol value of 0: "default priority. For use when priority is not
* otherwise specified".
*
* dcb_ieee_getapp_default_prio_mask - For a given device, find all APP entries
* of the form {$PRIO, ETHERTYPE, 0} and construct a bit mask of all default
* priorities set by these entries.
*/
u8 dcb_ieee_getapp_default_prio_mask(const struct net_device *dev)
{
int ifindex = dev->ifindex;
struct dcb_app_type *itr;
u8 mask = 0;
spin_lock_bh(&dcb_lock);
list_for_each_entry(itr, &dcb_app_list, list) {
if (itr->ifindex == ifindex &&
itr->app.selector == IEEE_8021QAZ_APP_SEL_ETHERTYPE &&
itr->app.protocol == 0 &&
itr->app.priority < IEEE_8021QAZ_MAX_TCS)
mask |= 1 << itr->app.priority;
}
spin_unlock_bh(&dcb_lock);
return mask;
}
EXPORT_SYMBOL(dcb_ieee_getapp_default_prio_mask);
static int __init dcbnl_init(void)
{
INIT_LIST_HEAD(&dcb_app_list);