This larger work addresses one of the bigger remaining issues on
tc's eBPF frontend, that is, to allow for persistent file descriptors.
Whenever tc parses the ELF object, extracts and loads maps into the
kernel, these file descriptors will be out of reach after the tc
instance exits.
Meaning, for simple (unnested) programs which contain one or
multiple maps, the kernel holds a reference, and they will live
on inside the kernel until the program holding them is unloaded,
but they will be out of reach for user space, even worse with
(also multiple nested) tail calls.
For this issue, we introduced the concept of an agent that can
receive the set of file descriptors from the tc instance creating
them, in order to be able to further inspect/update map data for
a specific use case. However, while that is more tied towards
specific applications, it still doesn't easily allow for sharing
maps accross multiple tc instances and would require a daemon to
be running in the background. F.e. when a map should be shared by
two eBPF programs, one attached to ingress, one to egress, this
currently doesn't work with the tc frontend.
This work solves exactly that, i.e. if requested, maps can now be
_arbitrarily_ shared between object files (PIN_GLOBAL_NS) or within
a single object (but various program sections, PIN_OBJECT_NS) without
"loosing" the file descriptor set. To make that happen, we use eBPF
object pinning introduced in kernel commit b2197755b263 ("bpf: add
support for persistent maps/progs") for exactly this purpose.
The shipped examples/bpf/bpf_shared.c code from this patch can be
easily applied, for instance, as:
- classifier-classifier shared:
tc filter add dev foo parent 1: bpf obj shared.o sec egress
tc filter add dev foo parent ffff: bpf obj shared.o sec ingress
- classifier-action shared (here: late binding to a dummy classifier):
tc actions add action bpf obj shared.o sec egress pass index 42
tc filter add dev foo parent ffff: bpf obj shared.o sec ingress
tc filter add dev foo parent 1: bpf bytecode '1,6 0 0 4294967295,' \
action bpf index 42
The toy example increments a shared counter on egress and dumps its
value on ingress (if no sharing (PIN_NONE) would have been chosen,
map value is 0, of course, due to the two map instances being created):
[...]
<idle>-0 [002] ..s. 38264.788234: : map val: 4
<idle>-0 [002] ..s. 38264.788919: : map val: 4
<idle>-0 [002] ..s. 38264.789599: : map val: 5
[...]
... thus if both sections reference the pinned map(s) in question,
tc will take care of fetching the appropriate file descriptor.
The patch has been tested extensively on both, classifier and
action sides.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
I found recently that, if I disabled address promotion in the kernel, that
ip addr flush dev <dev>
would fail with an EADDRNOTAVAIL errno (though the flush operation would in fact
flush all addresses from an interface properly)
Whats happening is that, if I add a primary and multiple secondary addresses to
an interface, the flush operation first ennumerates them all with a GETADDR |
DUMP operation, then sends a delete request for each address. But the kernel,
having promotion disabled, deletes all secondary addresses when the primary is
removed. That means, that several delete requests may still be pending in the
netlink request for addresses that have been removed on our behalf, resulting in
EADDRNOTAVAIL return codes.
It seems the simplest thing to do is to understand that EADDRUNAVAIL isn't a
fatal outcome on a flush operation, as it just indicates that an address which
you want to remove is already removed, so it can safely be ignored.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
CC: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Despite commit 45a82e5 ("iproute vxlan add support for fdb replace
command"), the 'fdb replace' command was not mentioned in bridge.8.
Signed-off-by: Phil Sutter <phil@nwl.cc>
The algorithm depends on the loop counter ('i') to increment by one in
each iteration. Though if running endlessly (count==0), the counter was
not incremented at all.
Also change formatting of the header printing conditional a bit so it's
hopefully easier to read.
Fixes: e7e2913 ("lnstat: run indefinitely by default")
Signed-off-by: Phil Sutter <phil@nwl.cc>
- Drop 'extern' keyword from all function prototypes.
- Make line breaking of print_* functions consistent.
- Make print_ntable() and ipntable_reset_filter() static and remove
their declaration.
- Drop declaration of non-existent ipaddr_list() and iproute_monitor().
Signed-off-by: Phil Sutter <phil@nwl.cc>
Since p->name is only IFNAMSIZ bytes, do not copy more than IFNAMSIZ - 1
bytes into it so there remains at least a single null byte in the end.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Instead of parsing an unsigned integer and checking boundaries, simply
parse u8. This and the added ttl alias 'hlim' provide consistency with
ip6tunnel.
Signed-off-by: Phil Sutter <phil@nwl.cc>
This makes output consistent with iptunnel, also supporting reverse DNS
lookup for remote address if requested.
Signed-off-by: Phil Sutter <phil@nwl.cc>
In iptunnel, declare loop variables inside the loop as done in
ip6tunnel.
Fix and simplify goto logic in ip6tunnel:
- Failure to read over header lines would have left fp opened.
- By returning directly upon fopen() failure, fp can be closed
unconditionally in the end.
Use the same goto logic in iptunnel, as well.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Instead of duplicating the same code six times (key, ikey and okey in
iptunnel and ip6tunnel), have a common parsing routine. This has the
added benefit of having the same verbose error message in ip6tunnel as
well as iptunnel.
I'm not sure if parsing an IPv4 address as key makes sense for
ip6tunnel, but the code was there before so this patch at least doesn't
make it worse.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Put whitespace in the beginning of optional parts, not as suffix
anywhere. Also drop double whitespaces in between words.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Instead of statically complaining about illegal inet address, use
get_family() to get the address family right.
Based on a patch by Hangbin Liu to print "inet6" for AF_INET6 made more
generic by me.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Add missing spaces around operators to increase readability. Aside from
that, make "preference" match a real synonym for "tos" and "dsfield" as
it's effect was identical to them.
Signed-off-by: Phil Sutter <phil@nwl.cc>
This fixes a few syntax errors and changes route filter help text to use
classid instead of flowid to be consistent with other filters' help
texts.
Signed-off-by: Phil Sutter <phil@nwl.cc>
