- 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.
- Use the correct IP header length variable for other-than-first packets.
- Remove redundant setting of the original IP header length in the first
packet's csum_data. (It's already set before ip_fragment() is called
in 1.147.)
on gnats-bugs in PR kern/29544.
Tested with an NFS client using default rwsize on an NFS server
with wm(4) interface configured IP4CSUM,TCP4CSUM,UDP4CSUM.
Prior revision required the server to have checksum offload disabled.
checksum is always in the L4 header by the time we get to this point. It
was occasionally not there due to a bug in tcp_respond, which has since
been fixed.
So, instead just stash the length of the L3 header in the high 16 bits of
csum_data.
(from an offset to the end of the packet), the pseudo-header checksum must be
calculated by software. So, provide it in the TCP/UDP header when
M_CSUM_NO_PSEUDOHDR is set in the interface's if_csum_flags_tx.
The start offset, the end of the IP header, is also provided in the high 16
bits of pkthdr.csum_data. Such that the driver need not examine the packet
at all.
XXX At the request of Jonathan Stone, note that sharing of if_csum_flags_tx &
pkthdr.csum_flags for checksum quirks should be re-evaluated.
to check if interface exists, as (1) if_index has different meaning
(2) ifindex2ifnet could become NULL when interface gets destroyed,
since when we have introduced dynamically-created interfaces. from kame
* Include "opt_inet.h" everywhere IP-ids are generated with ip_newid(),
so the RANDOM_IP_ID option is visible. Also in ip_id(), to ensure
the prototype for ip_randomid() is made visible.
* Add new sysctl to enable randomized IP-ids, provided the kernel was
configured with RANDOM_IP_ID. (The sysctl defaults to zero, and is
a read-only zero if RANDOM_IP_ID is not configured).
Note that the implementation of randomized IP ids is still defective,
and should not be enabled at all (even if configured) without
very careful deliberation. Caveat emptor.
due to demonstrated low-period repeated IDs from the randomized IP_id
code. Consensus is that the low-period repetition (much less than
2^15) is not suitable for general-purpose use.
Allocators of new IPv4 IDs should now call the function ip_newid().
Randomized IP_ids is now a config-time option, "options RANDOM_IP_ID".
ip_newid() can use ip_random-id()_IP_ID if and only if configured
with RANDOM_IP_ID. A sysctl knob should be provided.
This API may be reworked in the near future to support linear ip_id
counters per (src,dst) IP-address pair.
argument. So check so is non-NULL before doing the pointer-chasing
dance to find the PCB. (Unless and until we rework fast-ipsec and
KAME, to pass a struct in_pcbhdr * instead of the struct socket *).
reported by Shiva Shenoy
while we're here, fix another problem when the same interface address is
assigned to !IFF_MULTICAST and IFF_MULTICAST interface. if ip_multicast_if()
returns the first one, join/leave will fail, which is not an desired effect.
