linux-stable.git/net/ipv4/ip_output.c, branch v3.18

net: make skb_gso_segment error handling more robust

2014-10-20T16:38:13+00:00

skb_gso_segment has three possible return values:
1. a pointer to the first segmented skb
2. an errno value (IS_ERR())
3. NULL.  This can happen when GSO is used for header verification.

However, several callers currently test IS_ERR instead of IS_ERR_OR_NULL
and would oops when NULL is returned.

Note that these call sites should never actually see such a NULL return
value; all callers mask out the GSO bits in the feature argument.

However, there have been issues with some protocol handlers erronously not
respecting the specified feature mask in some cases.

It is preferable to get 'have to turn off hw offloading, else slow' reports
rather than 'kernel crashes'.

Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller

ipv4: dst_entry leak in ip_send_unicast_reply()

2014-10-17T19:30:12+00:00

ip_setup_cork() called inside ip_append_data() steals dst entry from rt to cork
and in case errors in __ip_append_data() nobody frees stolen dst entry

Fixes: 2e77d89b2fa8 ("net: avoid a pair of dst_hold()/dst_release() in ip_append_data()")
Signed-off-by: Vasily Averin 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

netfilter: use IS_ENABLED(CONFIG_BRIDGE_NETFILTER)

2014-10-02T16:30:54+00:00

In 34666d4 ("netfilter: bridge: move br_netfilter out of the core"),
the bridge netfilter code has been modularized.

Use IS_ENABLED instead of ifdef to cover the module case.

Fixes: 34666d4 ("netfilter: bridge: move br_netfilter out of the core")
Signed-off-by: Pablo Neira Ayuso

ipv4: rename ip_options_echo to __ip_options_echo()

2014-09-28T20:35:42+00:00

ip_options_echo() assumes struct ip_options is provided in &IPCB(skb)->opt
Lets break this assumption, but provide a helper to not change all call points.

ip_send_unicast_reply() gets a new struct ip_options pointer.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net-timestamp: add key to disambiguate concurrent datagrams

2014-08-05T23:35:54+00:00

Datagrams timestamped on transmission can coexist in the kernel stack
and be reordered in packet scheduling. When reading looped datagrams
from the socket error queue it is not always possible to unique
correlate looped data with original send() call (for application
level retransmits). Even if possible, it may be expensive and complex,
requiring packet inspection.

Introduce a data-independent ID mechanism to associate timestamps with
send calls. Pass an ID alongside the timestamp in field ee_data of
sock_extended_err.

The ID is a simple 32 bit unsigned int that is associated with the
socket and incremented on each send() call for which software tx
timestamp generation is enabled.

The feature is enabled only if SOF_TIMESTAMPING_OPT_ID is set, to
avoid changing ee_data for existing applications that expect it 0.
The counter is reset each time the flag is reenabled. Reenabling
does not change the ID of already submitted data. It is possible
to receive out of order IDs if the timestamp stream is not quiesced
first.

Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller

net-timestamp: SOCK_RAW and PING timestamping

2014-07-15T23:32:45+00:00

Add SO_TIMESTAMPING to sockets of type PF_INET[6]/SOCK_RAW:

Add the necessary sock_tx_timestamp calls to the datapath for RAW
sockets (ping sockets already had these calls).

Fix the IP output path to pass the timestamp flags on the first
fragment also for these sockets. The existing code relies on
transhdrlen != 0 to indicate a first fragment. For these sockets,
that assumption does not hold.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=77221

Tested SOCK_RAW on IPv4 and IPv6, not PING.

Signed-off-by: Willem de Bruijn 
Acked-by: Richard Cochran 
Signed-off-by: David S. Miller

inetpeer: get rid of ip_id_count

2014-06-02T18:00:41+00:00

Ideally, we would need to generate IP ID using a per destination IP
generator.

linux kernels used inet_peer cache for this purpose, but this had a huge
cost on servers disabling MTU discovery.

1) each inet_peer struct consumes 192 bytes

2) inetpeer cache uses a binary tree of inet_peer structs,
   with a nominal size of ~66000 elements under load.

3) lookups in this tree are hitting a lot of cache lines, as tree depth
   is about 20.

4) If server deals with many tcp flows, we have a high probability of
   not finding the inet_peer, allocating a fresh one, inserting it in
   the tree with same initial ip_id_count, (cf secure_ip_id())

5) We garbage collect inet_peer aggressively.

IP ID generation do not have to be 'perfect'

Goal is trying to avoid duplicates in a short period of time,
so that reassembly units have a chance to complete reassembly of
fragments belonging to one message before receiving other fragments
with a recycled ID.

We simply use an array of generators, and a Jenkin hash using the dst IP
as a key.

ipv6_select_ident() is put back into net/ipv6/ip6_output.c where it
belongs (it is only used from this file)

secure_ip_id() and secure_ipv6_id() no longer are needed.

Rename ip_select_ident_more() to ip_select_ident_segs() to avoid
unnecessary decrement/increment of the number of segments.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: add a sysctl to reflect the fwmark on replies

2014-05-13T22:35:08+00:00

Kernel-originated IP packets that have no user socket associated
with them (e.g., ICMP errors and echo replies, TCP RSTs, etc.)
are emitted with a mark of zero. Add a sysctl to make them have
the same mark as the packet they are replying to.

This allows an administrator that wishes to do so to use
mark-based routing, firewalling, etc. for these replies by
marking the original packets inbound.

Tested using user-mode linux:
 - ICMP/ICMPv6 echo replies and errors.
 - TCP RST packets (IPv4 and IPv6).

Signed-off-by: Lorenzo Colitti 
Signed-off-by: David S. Miller

net: rename local_df to ignore_df

2014-05-12T18:03:41+00:00

As suggested by several people, rename local_df to ignore_df,
since it means "ignore df bit if it is set".

Cc: Maciej Żenczykowski 
Cc: Florian Westphal 
Cc: David S. Miller 
Cc: Eric Dumazet 
Signed-off-by: Cong Wang 
Acked-by: Maciej Żenczykowski 
Signed-off-by: David S. Miller

net: ip: push gso skb forwarding handling down the stack

2014-05-07T19:49:07+00:00

Doing the segmentation in the forward path has one major drawback:

When using virtio, we may process gso udp packets coming
from host network stack.  In that case, netfilter POSTROUTING
will see one packet with udp header followed by multiple ip
fragments.

Delay the segmentation and do it after POSTROUTING invocation
to avoid this.

Fixes: fe6cc55f3a9 ("net: ip, ipv6: handle gso skbs in forwarding path")
Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller