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193391 |
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03-Jun-2009 |
rwatson |
Continue work to optimize performance of "options MAC" when no MAC policy modules are loaded by avoiding mbuf label lookups when policies aren't loaded, pushing further socket locking into MAC policy modules, and avoiding locking MAC ifnet locks when no policies are loaded:
- Check mac_policies_count before looking for mbuf MAC label m_tags in MAC Framework entry points. We will still pay label lookup costs if MAC policies are present but don't require labels (typically a single mbuf header field read, but perhaps further indirection if IPSEC or other m_tag consumers are in use).
- Further push socket locking for socket-related access control checks and events into MAC policies from the MAC Framework, so that sockets are only locked if a policy specifically requires a lock to protect a label. This resolves lock order issues during sonewconn() and also in local domain socket cross-connect where multiple socket locks could not be held at once for the purposes of propagatig MAC labels across multiple sockets. Eliminate mac_policy_count check in some entry points where it no longer avoids locking.
- Add mac_policy_count checking in some entry points relating to network interfaces that otherwise lock a global MAC ifnet lock used to protect ifnet labels.
Obtained from: TrustedBSD Project
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189797 |
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14-Mar-2009 |
rwatson |
Rework MAC Framework synchronization in a number of ways in order to improve performance:
- Eliminate custom reference count and condition variable to monitor threads entering the framework, as this had both significant overhead and behaved badly in the face of contention.
- Replace reference count with two locks: an rwlock and an sx lock, which will be read-acquired by threads entering the framework depending on whether a give policy entry point is permitted to sleep or not.
- Replace previous mutex locking of the reference count for exclusive access with write acquiring of both the policy list sx and rw locks, which occurs only when policies are attached or detached.
- Do a lockless read of the dynamic policy list head before acquiring any locks in order to reduce overhead when no dynamic policies are loaded; this a race we can afford to lose.
- For every policy entry point invocation, decide whether sleeping is permitted, and if not, use a _NOSLEEP() variant of the composition macros, which will use the rwlock instead of the sxlock. In some cases, we decide which to use based on allocation flags passed to the MAC Framework entry point.
As with the move to rwlocks/rmlocks in pfil, this may trigger witness warnings, but these should (generally) be false positives as all acquisition of the locks is for read with two very narrow exceptions for policy load/unload, and those code blocks should never acquire other locks.
Sponsored by: Google, Inc. Obtained from: TrustedBSD Project Discussed with: csjp (idea, not specific patch)
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184307 |
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26-Oct-2008 |
rwatson |
Add a MAC label, MAC Framework, and MAC policy entry points for IPv6 fragment reassembly queues.
This allows policies to label reassembly queues, perform access control checks when matching fragments to a queue, update a queue label when fragments are matched, and label the resulting reassembled datagram.
Obtained from: TrustedBSD Project
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173095 |
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28-Oct-2007 |
rwatson |
Move towards more explicit support for various network protocol stacks in the TrustedBSD MAC Framework:
- Add mac_atalk.c and add explicit entry point mac_netatalk_aarp_send() for AARP packet labeling, rather than using a generic link layer entry point.
- Add mac_inet6.c and add explicit entry point mac_netinet6_nd6_send() for ND6 packet labeling, rather than using a generic link layer entry point.
- Add expliict entry point mac_netinet_arp_send() for ARP packet labeling, and mac_netinet_igmp_send() for IGMP packet labeling, rather than using a generic link layer entry point.
- Remove previous genering link layer entry point, mac_mbuf_create_linklayer() as it is no longer used.
- Add implementations of new entry points to various policies, largely by replicating the existing link layer entry point for them; remove old link layer entry point implementation.
- Make MAC_IFNET_LOCK(), MAC_IFNET_UNLOCK(), and mac_ifnet_mtx global to the MAC Framework rather than static to mac_net.c as it is now needed outside of mac_net.c.
Obtained from: TrustedBSD Project
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