and syncache_respond() into its own generic function tcp_addoptions().
tcp_addoptions() is alignment agnostic and does optimal packing in all cases.
In struct tcpopt rename to_requested_s_scale to just to_wscale.
Add a comment with quote from RFC1323: "The Window field in a SYN (i.e.,
a <SYN> or <SYN,ACK>) segment itself is never scaled."
Reviewed by: silby, mohans, julian
Sponsored by: TCP/IP Optimization Fundraise 2005
upper-bounding it to the size of the initial socket buffer lower-bound it
to the smallest MSS we accept. Ideally we'd use the actual MSS information
here but it is not available yet.
For socket buffer auto sizing to be effective we need room to grow the
receive window. The window scale shift is determined at connection setup
and can't be changed afterwards. The previous, original, method effectively
just did a power of two roundup of the socket buffer size at connection
setup severely limiting the headroom for larger socket buffers.
Tested by: many (as part of the socket buffer auto sizing patch)
MFC after: 1 month
kernel. This LOR snuck in with some of the recent syncache changes. To
fix this, the inpcb handling was changed:
- Hang a MAC label off the syncache object
- When the syncache entry is initially created, we pickup the PCB lock
is held because we extract information from it while initializing the
syncache entry. While we do this, copy the MAC label associated with
the PCB and use it for the syncache entry.
- When the packet is transmitted, copy the label from the syncache entry
to the mbuf so it can be processed by security policies which analyze
mbuf labels.
This change required that the MAC framework be extended to support the
label copy operations from the PCB to the syncache entry, and then from
the syncache entry to the mbuf.
These functions really should be referencing the syncache structure instead
of the label. However, due to some of the complexities associated with
exposing this syncache structure we operate directly on it's label pointer.
This should be OK since we aren't making any access control decisions within
this code directly, we are merely allocating and copying label storage so
we can properly initialize mbuf labels for any packets the syncache code
might create.
This also has a nice side effect of caching. Prior to this change, the
PCB would be looked up/locked for each packet transmitted. Now the label
is cached at the time the syncache entry is initialized.
Submitted by: andre [1]
Discussed with: rwatson
[1] andre submitted the tcp_syncache.c changes
begun with a repo-copy of mac.h to mac_framework.h. sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.
This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.
Obtained from: TrustedBSD Project
Sponsored by: SPARTA
functionality:
- Remove a rwlock aquisition/release per generated syncookie. Locking
is now integrated with the bucket row locking of syncache itself and
syncookies no longer add any additional lock overhead.
- Syncookie secrets are different for and stored per syncache buck row.
Secrets expire after 16 seconds and are reseeded on-demand.
- The computational overhead for syncookie generation and verification
is one MD5 hash computation as before.
- Syncache can be turned off and run with syncookies only by setting the
sysctl net.inet.tcp.syncookies_only=1.
This implementation extends the orginal idea and first implementation
of FreeBSD by using not only the initial sequence number field to store
information but also the timestamp field if present. This way we can
keep track of the entire state we need to know to recreate the session in
its original form. Almost all TCP speakers implement RFC1323 timestamps
these days. For those that do not we still have to live with the known
shortcomings of the ISN only SYN cookies. The use of the timestamp field
causes the timestamps to be randomized if syncookies are enabled.
The idea of SYN cookies is to encode and include all necessary information
about the connection setup state within the SYN-ACK we send back and thus
to get along without keeping any local state until the ACK to the SYN-ACK
arrives (if ever). Everything we need to know should be available from
the information we encoded in the SYN-ACK.
A detailed description of the inner working of the syncookies mechanism
is included in the comments in tcp_syncache.c.
Reviewed by: silby (slightly earlier version)
Sponsored by: TCP/IP Optimization Fundraise 2005
o don't assign remote/local host/port information manually between provided
struct in_conninfo and struct syncache, bcopy() it instead
o rename sc_tsrecent to sc_tsreflect in struct syncache to better capture
the purpose of this field
o rename sc_request_r_scale to sc_requested_r_scale for ditto reasons
o fix IPSEC error case printf's to report correct function name
o in syncache_socket() only transpose enhanced tcp options parameters to
struct tcpcb when the inpcb doesn't has TF_NOOPT set
o in syncache_respond() reorder stack variables
o in syncache_respond() remove bogus KASSERT()
No functional changes.
Sponsored by: TCP/IP Optimization Fundraise 2005
memory location for already existing/initialized mutexes. With random
data in the memory location this fails (ie. after a soft reboot).
Reported by: brueffer, YAMAMOTO Shigeru
Submitted by: YAMAMOTO Shigeru <shigeru-at-iij.ad.jp>
as possible for the syncache_add() case. The syncache timer no longer
aquires the tcpinfo lock and timeout/retransmit runs can happen in
parallel with bucket granularity.
On a P4 the additional locks cause a slight degression of 0.7% in tcp
connections per second. When IP and TCP input are deserialized and
can run in parallel this little overhead can be neglected. The syncookie
handling still leaves room for improvement and its random salts may be
moved to the syncache bucket head structures to remove the second lock
operation currently required for it. However this would be a more
involved change from the way syncookies work at the moment.
Reviewed by: rwatson
Tested by: rwatson, ps (earlier version)
Sponsored by: TCP/IP Optimization Fundraise 2005
consumers ignore the return value, soabort() is required to succeed,
and protocols produce errors here to report multiple freeing of the
pcb, which we hope to eliminate.
right from the beginning and partly clean up the differences in handling
between SYN_SENT and SYN_RCVD (syncache).
Further changes to this code to come. This is a first incremental step
to a general overhaul and streamlining of the TCP code.
PR: kern/15095
PR: kern/92690 (partly)
Reviewed by: qingli (and tested with ANVL)
Sponsored by: TCP/IP Optimization Fundraise 2005
in syncache_lookup() is not cleared and may lead to an arbitrary and
bogus rtentry pointer which later gets free'd.
Reviewed by: andre
MFC after: 3 days
that currently can't be triggered. But better be safe than sorry
later on. Additionally it properly silences Coverity Prevent for
future tests.
Found by: Coverity Prevent(tm)
Coverity ID: CID802
Sponsored by: TCP/IP Optimization Fundraise 2005
MFC after: 3 days
include ip_options.h into all files making use of IP Options functions.
From ip_input.c rev 1.306:
ip_dooptions(struct mbuf *m, int pass)
save_rte(m, option, dst)
ip_srcroute(m0)
ip_stripoptions(m, mopt)
From ip_output.c rev 1.249:
ip_insertoptions(m, opt, phlen)
ip_optcopy(ip, jp)
ip_pcbopts(struct inpcb *inp, int optname, struct mbuf *m)
No functional changes in this commit.
Discussed with: rwatson
Sponsored by: TCP/IP Optimization Fundraise 2005
Having an additional MT_HEADER mbuf type is superfluous and redundant
as nothing depends on it. It only adds a layer of confusion. The
distinction between header mbuf's and data mbuf's is solely done
through the m->m_flags M_PKTHDR flag.
Non-native code is not changed in this commit. For compatibility
MT_HEADER is mapped to MT_DATA.
Sponsored by: TCP/IP Optimization Fundraise 2005
If TCP Signatures are enabled, the maximum allowed sack blocks aren't
going to fit. The fix is to compute how many sack blocks fit and tack
these on last. Also on SYNs, defer padding until after the SACK
PERMITTED option has been added.
Found by: Mohan Srinivasan.
Submitted by: Mohan Srinivasan, Noritoshi Demizu.
Reviewed by: Raja Mukerji.
- If the peer sends the Signature option in the SYN, use of Timestamps
and Window Scaling were disabled (even if the peer supports them).
- The sender must not disable signatures if the option is absent in
the received SYN. (See comment in syncache_add()).
Found, Submitted by: Noritoshi Demizu <demizu at dd dot ij4u dot or dot jp>.
Reviewed by: Mohan Srinivasan <mohans at yahoo-inc dot com>.
A complete rationale and discussion is given in this message
and the resulting discussion:
http://docs.freebsd.org/cgi/mid.cgi?4177C8AD.6060706
Note that this commit removes only the functional part of T/TCP
from the tcp_* related functions in the kernel. Other features
introduced with RFC1644 are left intact (socket layer changes,
sendmsg(2) on connection oriented protocols) and are meant to
be reused by a simpler and less intrusive reimplemention of the
previous T/TCP functionality.
Discussed on: -arch
it travels through the IP stack. This wasn't much of a problem because IP
source routing is disabled by default but when enabled together with SMP and
preemption it would have very likely cross-corrupted the IP options in transit.
The IP source route options of a packet are now stored in a mtag instead of the
global variable.
- Trailing tab/space cleanup
- Remove spurious spaces between or before tabs
This change avoids touching files that Andre likely has in his working
set for PFIL hooks changes for IPFW/DUMMYNET.
Approved by: re (scottl)
Submitted by: Xin LI <delphij@frontfree.net>
have already done this, so I have styled the patch on their work:
1) introduce a ip_newid() static inline function that checks
the sysctl and then decides if it should return a sequential
or random IP ID.
2) named the sysctl net.inet.ip.random_id
3) IPv6 flow IDs and fragment IDs are now always random.
Flow IDs and frag IDs are significantly less common in the
IPv6 world (ie. rarely generated per-packet), so there should
be smaller performance concerns.
The sysctl defaults to 0 (sequential IP IDs).
Reviewed by: andre, silby, mlaier, ume
Based on: NetBSD
MFC after: 2 months
for structures with timers in them. It might be that a timer might fire
even when the associated structure has already been free'd. Having type-
stable storage in this case is beneficial for graceful failure handling and
debugging.
Discussed with: bosko, tegge, rwatson
for the SYN|ACK packet and then letting in6_pcbconnect set the
flowlabel later. Arange for the syncache/syncookie code to set and
recall the flow label so that the flowlabel used for the SYN|ACK
is consistent. This is done by using some of the cookie (when tcp
cookies are enabeled) and by stashing the flowlabel in syncache.
Tested and Discovered by: Orla McGann <orly@cnri.dit.ie>
Approved by: ume, silby
MFC after: 1 month
originated on RELENG_4 and was ported to -CURRENT.
The scoreboarding code was obtained from OpenBSD, and many
of the remaining changes were inspired by OpenBSD, but not
taken directly from there.
You can enable/disable sack using net.inet.tcp.do_sack. You can
also limit the number of sack holes that all senders can have in
the scoreboard with net.inet.tcp.sackhole_limit.
Reviewed by: gnn
Obtained from: Yahoo! (Mohan Srinivasan, Jayanth Vijayaraghavan)
SOCK_LOCK(so):
- Hold socket lock over calls to MAC entry points reading or
manipulating socket labels.
- Assert socket lock in MAC entry point implementations.
- When externalizing the socket label, first make a thread-local
copy while holding the socket lock, then release the socket lock
to externalize to userspace.
labeling new mbufs created from sockets/inpcbs in IPv4. This helps avoid
the need for socket layer locking in the lower level network paths
where inpcb locks are already frequently held where needed. In
particular:
- Use the inpcb for label instead of socket in raw_append().
- Use the inpcb for label instead of socket in tcp_output().
- Use the inpcb for label instead of socket in tcp_respond().
- Use the inpcb for label instead of socket in tcp_twrespond().
- Use the inpcb for label instead of socket in syncache_respond().
While here, modify tcp_respond() to avoid assigning NULL to a stack
variable and centralize assertions about the inpcb when inp is
assigned.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, McAfee Research
