jumping to dropunlock to avoid a panic. While here move the calls to
ipsec4_in_reject() and ipsec6_in_reject() so they are after we obtain
the lock on inp.
Original patch to avoid panic: pjd
Review of locking adjustments: gnn, sam
Approved by: re (rwatson)
<netinet/tcp_fsm.h> is included into any compilation unit that needs
tcpstates[]. Also remove incorrect extern declarations and TCPDEBUG
conditionals. This allows kernels both with and without TCPDEBUG to
build, and unbreaks the tinderbox.
Approved by: re (rwatson)
sys.net.inet.tcp.log_debug = 1
It defaults to enabled for the moment and is to be turned off for
the next release like other diagnostics from development branches.
It is important to note that sysctl sys.net.inet.tcp.log_in_vain
uses the same logging function as log_debug. Enabling of the former
also causes the latter to engage, but not vice versa.
Use consistent terminology in tcp log messages:
"ignored" means a segment contains invalid flags/information and
is dropped without changing state or issuing a reply.
"rejected" means a segments contains invalid flags/information but
is causing a reply (usually RST) and may cause a state change.
Approved by: re (rwatson)
syncache_rst().
o Fix tests for flag combinations of RST and SYN, ACK, FIN. Before
a RST for a connection in syncache did not properly free the entry.
o Add more detailed logging.
Approved by: re (rwatson)
This commit includes only the kernel files, the rest of the files
will follow in a second commit.
Reviewed by: bz
Approved by: re
Supported by: Secure Computing
be called with an incorrect segment end value. tcp_reass() may
trim segments when they overlap with already existing ones in the
reassembly queue. Instead of saving the segment end value before
the call to tcp_reass() compute it on the fly based on the effective
segment length afterwards.
This bug was not really problematic as no information got lost and
the eventual SACK information computation was correct nontheless.
MFC after: 1 week
and simplify handling of the send/receive window scaling. No
change in effective behavour.
RFC1323 requires the window field in a SYN (i.e., a <SYN> or
<SYN,ACK>) segment itself never be scaled.
Noticed by: yar
in tcp_input():
o tighten the checks on allowed TCP flags to be RFC793 and
tcp-secure conform
o log check failures to syslog at LOG_DEBUG level
o rearrange the code flow to be easier to follow
o add KASSERTs to validate assumptions of the code flow
Add sysctl net.inet.tcp.syncache.rst_on_sock_fail defaulting to enable
that controls the behavior on socket creation failure for a otherwise
successful 3-way handshake. The socket creation can fail due to global
memory shortage, listen queue limits and file descriptor limits. The
sysctl allows to chose between two options to deal with this. One is
to send a reset to the other endpoint to notify it about the failure
(default). The other one is to ignore and treat the failure as a
transient error and have the other endpoint retransmit for another try.
Reviewed by: rwatson (in general)
for use thoughout the tcp subsystem.
It is IPv4 and IPv6 aware creates a line in the following format:
"TCP: [1.2.3.4]:50332 to [1.2.3.4]:80 tcpflags <RST>"
A "\n" is not included at the end. The caller is supposed to add
further information after the standard tcp log header.
The function returns a NUL terminated string which the caller has
to free(s, M_TCPLOG) after use. All memory allocation is done
with M_NOWAIT and the return value may be NULL in memory shortage
situations.
Either struct in_conninfo || (struct tcphdr && (struct ip || struct
ip6_hdr) have to be supplied.
Due to ip[6].h header inclusion limitations and ordering issues the
struct ip and struct ip6_hdr parameters have to be casted and passed
as void * pointers.
tcp_log_addrs(struct in_conninfo *inc, struct tcphdr *th, void *ip4hdr,
void *ip6hdr)
Usage example:
struct ip *ip;
char *tcplog;
if (tcplog = tcp_log_addrs(NULL, th, (void *)ip, NULL)) {
log(LOG_DEBUG, "%s; %s: Connection attempt to closed port\n",
tcplog, __func__);
free(s, M_TCPLOG);
}
other than repo copied tcp_subr.c into tcp_timewait.c#1.284:
tcp_input.c#1.350 tcp_timewait() -> tcp_twcheck()
tcp_timer.c#1.92 tcp_timer_2msl_reset() -> tcp_tw_2msl_reset()
tcp_timer.c#1.92 tcp_timer_2msl_stop() -> tcp_tw_2msl_stop()
tcp_timer.c#1.92 tcp_timer_2msl_tw() -> tcp_tw_2msl_scan()
This is a mechanical move with appropriate renames and making
them static if used only locally.
The tcp_tw_2msl_scan() cleanup function is still run from the
tcp_slowtimo() in tcp_timer.c.
functions from their origininal place to their own files.
TCP Reassembly from tcp_input.c -> tcp_reass.c
TCP Timewait from tcp_subr.c -> tcp_timewait.c
and change it to a void function.
We use a compressed structure for TCPS_TIME_WAIT to save memory. Any late
late segments arriving for such a connection is handled directly in the TW
code.
from the incoming SYN handling section of tcp_input().
Enforcement of the accept queue limits is done by sonewconn() after the
3WHS is completed. It is not necessary to have an earlier check before a
connection request enters the SYN cache awaiting the full handshake. It
rather limits the effectiveness of the syncache by preventing legit and
illegit connections from entering it and having them shaken out before we
hit the real limit which may have vanished by then.
Change return value of syncache_add() to void. No status communication
is required.
when the ACK is invalid and doesn't belong to any registered connection,
either in syncache or through SYN cookies. True but a NULL struct socket
is returned when the 3WHS completed but the socket could not be created
due to insufficient resources or limits reached.
For both cases an RST is sent back in tcp_input().
A logic error leading to a panic is fixed where syncache_expand() would
free the mbuf on socket allocation failure but tcp_input() later supplies
it to tcp_dropwithreset() to issue a RST to the peer.
Reported by: kris (the panic)
directly to a merged model where only one callout, the next to fire,
is registered.
Instead of callout_reset(9) and callout_stop(9) the new function
tcp_timer_activate() is used which then internally manages the callout.
The single new callout is a mutex callout on inpcb simplifying the
locking a bit.
tcp_timer() is the called function which handles all race conditions
in one place and then dispatches the individual timer functions.
Reviewed by: rwatson (earlier version)
tcp_input() to syncache_socket() where it belongs and the majority
of it already happens.
The "tp->snd_up = tp->snd_una" is removed as it is done with the
tcp_sendseqinit() macro a few lines earlier.
o tcp_input() now handles TCP segment sanity checks and preparations
including the INPCB lookup and syncache.
o tcp_do_segment() handles all data and ACK processing and is IPv4/v6
agnostic.
Change all KASSERT() messages to ("%s: ", __func__).
The changes in this commit are primarily of mechanical nature and no
functional changes besides the function split are made.
Discussed with: rwatson
