f823f36012
Implement loading of .BTF section from object file and build up
internal table for retrieving key/value id related to maps in
the BPF program. Latter is done by setting up struct btf_type
table.
One of the issues is that there's a disconnect between the data
types used in the map and struct bpf_elf_map, meaning the underlying
types are unknown from the map description. One way to overcome
this is to add a annotation such that the loader will recognize
the relation to both. BPF_ANNOTATE_KV_PAIR(map_foo, struct key,
struct val); has been added to the API that programs can use.
The loader will then pick the corresponding key/value type ids and
attach it to the maps for creation. This can later on be dumped via
bpftool for introspection.
Example with test_xdp_noinline.o from kernel selftests:
[...]
struct ctl_value {
union {
__u64 value;
__u32 ifindex;
__u8 mac[6];
};
};
struct bpf_map_def __attribute__ ((section("maps"), used)) ctl_array = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(struct ctl_value),
.max_entries = 16,
.map_flags = 0,
};
BPF_ANNOTATE_KV_PAIR(ctl_array, __u32, struct ctl_value);
[...]
Above could also further be wrapped in a macro. Compiling through LLVM and
converting to BTF:
# llc --version
LLVM (http://llvm.org/):
LLVM version 7.0.0svn
Optimized build.
Default target: x86_64-unknown-linux-gnu
Host CPU: skylake
Registered Targets:
bpf - BPF (host endian)
bpfeb - BPF (big endian)
bpfel - BPF (little endian)
[...]
# clang [...] -O2 -target bpf -g -emit-llvm -c test_xdp_noinline.c -o - |
llc -march=bpf -mcpu=probe -mattr=dwarfris -filetype=obj -o test_xdp_noinline.o
# pahole -J test_xdp_noinline.o
Checking pahole dump of BPF object file:
# file test_xdp_noinline.o
test_xdp_noinline.o: ELF 64-bit LSB relocatable, *unknown arch 0xf7* version 1 (SYSV), with debug_info, not stripped
# pahole test_xdp_noinline.o
[...]
struct ctl_value {
union {
__u64 value; /* 0 8 */
__u32 ifindex; /* 0 4 */
__u8 mac[0]; /* 0 0 */
}; /* 0 8 */
/* size: 8, cachelines: 1, members: 1 */
/* last cacheline: 8 bytes */
};
Now loading into kernel and dumping the map via bpftool:
# ip -force link set dev lo xdp obj test_xdp_noinline.o sec xdp-test
# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 xdpgeneric/id:227 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
[...]
# bpftool prog show id 227
227: xdp tag a85e060c275c5616 gpl
loaded_at 2018-07-17T14:41:29+0000 uid 0
xlated 8152B not jited memlock 12288B map_ids 381,385,386,382,384,383
# bpftool map dump id 386
[{
"key": 0,
"value": {
"": {
"value": 0,
"ifindex": 0,
"mac": []
}
}
},{
"key": 1,
"value": {
"": {
"value": 0,
"ifindex": 0,
"mac": []
}
}
},{
[...]
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David Ahern <dsahern@gmail.com>
|
||
|---|---|---|
| bash-completion | ||
| bridge | ||
| devlink | ||
| doc/actions | ||
| etc/iproute2 | ||
| examples | ||
| genl | ||
| include | ||
| ip | ||
| lib | ||
| man | ||
| misc | ||
| netem | ||
| rdma | ||
| schema | ||
| tc | ||
| testsuite | ||
| tipc | ||
| .gitignore | ||
| COPYING | ||
| Makefile | ||
| README | ||
| README.decnet | ||
| README.devel | ||
| README.distribution | ||
| README.iproute2+tc | ||
| README.lnstat | ||
| configure | ||
README
This is a set of utilities for Linux networking.
Information:
https://wiki.linuxfoundation.org/networking/iproute2
Download:
http://www.kernel.org/pub/linux/utils/net/iproute2/
Stable version repository:
git://git.kernel.org/pub/scm/network/iproute2/iproute2.git
Development repository:
git://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git
How to compile this.
--------------------
1. libdbm
arpd needs to have the berkeleydb development libraries. For Debian
users this is the package with a name like libdbX.X-dev.
DBM_INCLUDE points to the directory with db_185.h which
is the include file used by arpd to get to the old format Berkeley
database routines. Often this is in the db-devel package.
2. make
The makefile will automatically build a config.mk file which
contains definitions of libraries that may or may not be available
on the system such as: ATM, ELF, MNL, and SELINUX.
3. To make documentation, cd to doc/ directory , then
look at start of Makefile and set correct values for
PAGESIZE=a4 , ie: a4 , letter ... (string)
PAGESPERPAGE=2 , ie: 1 , 2 ... (numeric)
and make there. It assumes, that latex, dvips and psnup
are in your path.
4. This package includes matching sanitized kernel headers because
the build environment may not have up to date versions. See Makefile
if you have special requirements and need to point at different
kernel include files.
Stephen Hemminger
stephen@networkplumber.org
Alexey Kuznetsov
kuznet@ms2.inr.ac.ru