- don't use void * for pointer arithmetic
- don't try to modify const parameters
A kernel with 'options TCP_SIGNATURE' works as well as it ever did, now.
(ie, clunky, but passable)
route_in6, struct route_iso), replacing all caches with a struct
route.
The principle benefit of this change is that all of the protocol
families can benefit from route cache-invalidation, which is
necessary for correct routing. Route-cache invalidation fixes an
ancient PR, kern/3508, at long last; it fixes various other PRs,
also.
Discussions with and ideas from Joerg Sonnenberger influenced this
work tremendously. Of course, all design oversights and bugs are
mine.
DETAILS
1 I added to each address family a pool of sockaddrs. I have
introduced routines for allocating, copying, and duplicating,
and freeing sockaddrs:
struct sockaddr *sockaddr_alloc(sa_family_t af, int flags);
struct sockaddr *sockaddr_copy(struct sockaddr *dst,
const struct sockaddr *src);
struct sockaddr *sockaddr_dup(const struct sockaddr *src, int flags);
void sockaddr_free(struct sockaddr *sa);
sockaddr_alloc() returns either a sockaddr from the pool belonging
to the specified family, or NULL if the pool is exhausted. The
returned sockaddr has the right size for that family; sa_family
and sa_len fields are initialized to the family and sockaddr
length---e.g., sa_family = AF_INET and sa_len = sizeof(struct
sockaddr_in). sockaddr_free() puts the given sockaddr back into
its family's pool.
sockaddr_dup() and sockaddr_copy() work analogously to strdup()
and strcpy(), respectively. sockaddr_copy() KASSERTs that the
family of the destination and source sockaddrs are alike.
The 'flags' argumet for sockaddr_alloc() and sockaddr_dup() is
passed directly to pool_get(9).
2 I added routines for initializing sockaddrs in each address
family, sockaddr_in_init(), sockaddr_in6_init(), sockaddr_iso_init(),
etc. They are fairly self-explanatory.
3 structs route_in6 and route_iso are no more. All protocol families
use struct route. I have changed the route cache, 'struct route',
so that it does not contain storage space for a sockaddr. Instead,
struct route points to a sockaddr coming from the pool the sockaddr
belongs to. I added a new method to struct route, rtcache_setdst(),
for setting the cache destination:
int rtcache_setdst(struct route *, const struct sockaddr *);
rtcache_setdst() returns 0 on success, or ENOMEM if no memory is
available to create the sockaddr storage.
It is now possible for rtcache_getdst() to return NULL if, say,
rtcache_setdst() failed. I check the return value for NULL
everywhere in the kernel.
4 Each routing domain (struct domain) has a list of live route
caches, dom_rtcache. rtflushall(sa_family_t af) looks up the
domain indicated by 'af', walks the domain's list of route caches
and invalidates each one.
one or two segments on partial acks. even if sack_bytes_rxmt==0,
if we are in fast recovory with sack, snd_cwnd has somewhat special
meaning here. PR/34749.
happen in the TCP stack, this interface calls the specified callback to
handle the situation according to the currently selected congestion
control algorithm.
A new sysctl node was created: net.inet.tcp.congctl.{available,selected}
with obvious meanings.
The old net.inet.tcp.newreno MIB was removed.
The API is discussed in tcp_congctl(9).
In the near future, it will be possible to selected a congestion control
algorithm on a per-socket basis.
Discussed on tech-net and reviewed by <yamt>.
Both available for IPv4 and IPv6.
Basic implementation test results are available at
http://netbsd-soc.sourceforge.net/projects/ecn/testresults.html.
Work sponsored by the Google Summer of Code project 2006.
Special thanks to Kentaro Kurahone, Allen Briggs and Matt Thomas for their
help, comments and support during the project.
http://www.gont.com.ar/drafts/icmp-attacks-against-tcp.html
1. Don't act on ICMP-need-frag immediately if adhoc checks on the
advertised MTU fail. The MTU update is delayed until a TCP retransmit
happens.
2. Ignore ICMP Source Quench messages meant for TCP connections.
From OpenBSD.
- for ipv4, defer decision to ip layer as h/w checksum offloading does
so that it can check the actual interface the packet is going to.
- for ipv6, disable it.
(maybe will be revisited when it implements h/w checksum offloading.)
ok'ed by Jason Thorpe.
- introduce t_segqlen, the number of segments in segq/timeq.
the name is from freebsd.
- rather than maintaining a copy of sack blocks (rcv_sack_block[]),
build it directly from the segment list when needed.
http://www.sigusr1.org/~kurahone/tcp-sack-netbsd-02152005.diff.gz
Fixes in that patch for pre-existing TCP pcb initializations were already
committed to NetBSD-current, so are not included in this commit.
The SACK patch has been observed to correctly negotiate and respond,
to SACKs in wide-area traffic.
There are two indepenently-observed, as-yet-unresolved anomalies:
First, seeing unexplained delays between in fast retransmission
(potentially explainable by an 0.2sec RTT between adjacent
ethernet/wifi NICs); and second, peculiar and unepxlained TCP
retransmits observed over an ath0 card.
After discussion with several interested developers, I'm committing
this now, as-is, for more eyes to use and look over. Current hypothesis
is that the anomalies above may in fact be due to link/level (hardware,
driver, HAL, firmware) abberations in the test setup, affecting both
Kentaro's wired-Ethernet NIC and in my two (different) WiFi NICs.
