For multi-function programs, loading the address of a callee
function to a register requires emitting instructions whose
count varies from one to five depending on the nature of the
address.

Since we come to know of the callee's address only before the
extra pass, the number of instructions required to load this
address may vary from what was previously generated. This can
make the JITed image grow or shrink.

To avoid this, we should generate a constant five-instruction
when loading function addresses by padding the optimized load
sequence with NOPs.
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

The imm field of a bpf instruction is a signed 32-bit integer.
For JITed bpf-to-bpf function calls, it holds the offset of the
start address of the callee's JITed image from __bpf_call_base.

For some architectures, such as powerpc64, this offset may be
as large as 64 bits and cannot be accomodated in the imm field
without truncation.

We resolve this by:

[1] Additionally using the auxiliary data of each function to
    keep a list of start addresses of the JITed images for all
    functions determined by the verifier.

[2] Retaining the subprog id inside the off field of the call
    instructions and using it to index into the list mentioned
    above and lookup the callee's address.

To make sure that the existing JIT compilers continue to work
without requiring changes, we keep the imm field as it is.
Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Sparse warning:
kernel/bpf/btf.c:1985:34: warning: Variable length array is used.

This patch directly uses ARRAY_SIZE().

Fixes: f80442a4 ("bpf: btf: Change how section is supported in btf_header")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

On arm32, 'cd tools/testing/selftests/bpf && make' fails with:

libbpf.c:80:10: error: format ‘%ld’ expects argument of type ‘long int’, but argument 4 has type ‘int64_t {aka long long int}’ [-Werror=format=]
   (func)("libbpf: " fmt, ##__VA_ARGS__); \
          ^
libbpf.c:83:30: note: in expansion of macro ‘__pr’
 #define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
                              ^~~~
libbpf.c:1072:3: note: in expansion of macro ‘pr_warning’
   pr_warning("map:%s value_type:%s has BTF type_size:%ld != value_size:%u\n",

To fix, typecast 'key_size' and amend format string.
Signed-off-by: Sirio Balmelli <sirio@b-ad.ch>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Selftests fail to build on several distros/architectures because of
	missing headers files.

On a Ubuntu/x86_64 some missing headers are:
	asm/byteorder.h, asm/socket.h, asm/sockios.h

On a Debian/arm32 build already fails at sys/cdefs.h

In both cases, these already exist in /usr/include/<arch-specific-dir>,
but Clang does not include these when using '-target bpf' flag,
since it is no longer compiling against the host architecture.

The solution is to:

- run Clang without '-target bpf' and extract the include chain for the
current system

- add these to the bpf build with '-idirafter'

The choice of -idirafter is to catch this error without injecting
unexpected include behavior: if an arch-specific tree is built
for bpf in the future, this will be correctly found by Clang.
Signed-off-by: Sirio Balmelli <sirio@b-ad.ch>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Martin KaFai Lau says:

====================
This patch set makes some changes to cleanup the unused
bits in BTF uapi.  It also makes the btf_header extensible.

Please see individual patches for details.

v2:
- Remove NR_SECS from patch 2
- Remove "unsigned" check on array->index_type from patch 3
- Remove BTF_INT_VARARGS and further limit BTF_INT_ENCODING
  from 8 bits to 4 bits in patch 4
- Adjustments in test_btf.c to reflect changes in v2
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

This patch does the followings:
1. Modify libbpf and test_btf to reflect the uapi changes in btf
2. Add test for the btf_header changes
3. Add tests for array->index_type
4. Add err_str check to the tests
5. Fix a 4 bytes hole in "struct test #1" by swapping "m" and "n"
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

This patch sync the uapi bpf.h and btf.h to tools.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

In "struct bpf_map_info", the name "btf_id", "btf_key_id" and "btf_value_id"
could cause confusion because the "id" of "btf_id" means the BPF obj id
given to the BTF object while
"btf_key_id" and "btf_value_id" means the BTF type id within
that BTF object.

To make it clear, btf_key_id and btf_value_id are
renamed to btf_key_type_id and btf_value_type_id.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

This patch does the followings:
1. Limit BTF_MAX_TYPES and BTF_MAX_NAME_OFFSET to 64k.  We can
   raise it later.

2. Remove the BTF_TYPE_PARENT and BTF_STR_TBL_ELF_ID.  They are
   currently encoded at the highest bit of a u32.
   It is because the current use case does not require supporting
   parent type (i.e type_id referring to a type in another BTF file).
   It also does not support referring to a string in ELF.

   The BTF_TYPE_PARENT and BTF_STR_TBL_ELF_ID checks are replaced
   by BTF_TYPE_ID_CHECK and BTF_STR_OFFSET_CHECK which are
   defined in btf.c instead of uapi/linux/btf.h.

3. Limit the BTF_INFO_KIND from 5 bits to 4 bits which is enough.
   There is unused bits headroom if we ever needed it later.

4. The root bit in BTF_INFO is also removed because it is not
   used in the current use case.

5. Remove BTF_INT_VARARGS since func type is not supported now.
   The BTF_INT_ENCODING is limited to 4 bits instead of 8 bits.

The above can be added back later because the verifier
ensures the unused bits are zeros.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Instead of ingoring the array->index_type field.  Enforce that
it must be a BTF_KIND_INT in size 1/2/4/8 bytes.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

There are currently unused section descriptions in the btf_header.  Those
sections are here to support future BTF use cases.  For example, the
func section (func_off) is to support function signature (e.g. the BPF
prog function signature).

Instead of spelling out all potential sections up-front in the btf_header.
This patch makes changes to btf_header such that extending it (e.g. adding
a section) is possible later.  The unused ones can be removed for now and
they can be added back later.

This patch:
1. adds a hdr_len to the btf_header.  It will allow adding
sections (and other info like parent_label and parent_name)
later.  The check is similar to the existing bpf_attr.
If a user passes in a longer hdr_len, the kernel
ensures the extra tailing bytes are 0.

2. allows the section order in the BTF object to be
different from its sec_off order in btf_header.

3. each sec_off is followed by a sec_len.  It must not have gap or
overlapping among sections.

The string section is ensured to be at the end due to the 4 bytes
alignment requirement of the type section.

The above changes will allow enough flexibility to
add new sections (and other info) to the btf_header later.

This patch also removes an unnecessary !err check
at the end of btf_parse().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

This patch exposes check_uarg_tail_zero() which will
be reused by a later BTF patch.  Its name is changed to
bpf_check_uarg_tail_zero().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

David Ahern says:

====================
Packets that exceed the egress MTU can not be forwarded in the fast path.
Add IPv4 and IPv6 MTU helpers that take a FIB lookup result (versus the
typical dst path) and add the calls to bpf_ipv{4,6}_fib_lookup.

v2
- add ip6_mtu_from_fib6 to ipv6_stub
- only call the new MTU helpers for fib lookups in XDP path; skb
  path uses is_skb_forwardable to determine if the packet can be
  sent via the egress device from the FIB lookup
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Add check that egress MTU can handle packet to be forwarded. If
the MTU is less than the packet length, return 0 meaning the
packet is expected to continue up the stack for help - eg.,
fragmenting the packet or sending an ICMP.

The XDP path needs to leverage the FIB entry for an MTU on the
route spec or an exception entry for a given destination. The
skb path lets is_skb_forwardable decide if the packet can be
sent.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Determine path MTU from a FIB lookup result. Logic is based on
ip6_dst_mtu_forward plus lookup of nexthop exception.

Add ip6_dst_mtu_forward to ipv6_stubs to handle access by core
bpf code.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Determine path MTU from a FIB lookup result. Logic is a distillation of
ip_dst_mtu_maybe_forward.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Björn Töpel says:

====================
This the second follow-up set. The first four patches are uapi
changes:

* Removing rebind support
* Getting rid of structure hole
* Removing explicit cache line alignment
* Stricter bind checks

The last patches do some cleanups, where the umem and refcount_t
changes were suggested by Daniel.

* Add a missing write-barrier and use READ_ONCE for data-dependencies
* Clean up umem and do proper locking
* Convert atomic_t to refcount_t
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Introduce refcount_t, in favor of atomic_t.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

As suggested by Daniel Borkmann, the umem setup code was a too
defensive and complex. Here, we reduce the number of checks. Also, the
memory pinning is now folded into the umem creation, and we do correct
locking.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Here, we add a missing write-barrier, and use READ_ONCE for the
data-dependency barrier.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Adapt xdpsock to use the new getsockopt introduced in the previous
commit.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

In this commit we remove the explicit ring structure from the the
uapi. It is tricky for an uapi to depend on a certain L1 cache line
size, since it can differ for variants of the same architecture. Now,
we let the user application determine the offsets of the producer,
consumer and descriptors by asking the socket via getsockopt.

A typical flow would be (Rx ring):

  struct xdp_mmap_offsets off;
  struct xdp_desc *ring;
  u32 *prod, *cons;
  void *map;
  ...

  getsockopt(fd, SOL_XDP, XDP_MMAP_OFFSETS, &off, &optlen);

  map = mmap(NULL, off.rx.desc +
		   NUM_DESCS * sizeof(struct xdp_desc),
		   PROT_READ | PROT_WRITE,
		   MAP_SHARED | MAP_POPULATE, sfd,
		   XDP_PGOFF_RX_RING);
  prod = map + off.rx.producer;
  cons = map + off.rx.consumer;
  ring = map + off.rx.desc;
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Validate the queue id against both Rx and Tx on the netdev. Also, make
sure that the queue exists at xmit time.
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Tested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Move the sxdp_flags up, avoiding a hole in the uapi structure.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Supporting rebind, i.e. after a successful bind the process can call
bind again without closing the socket, makes the AF_XDP setup state
machine more complex. Constrain the state space, by not supporting
rebind.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

John Fastabend says:

====================
In this series we add the ability for sk msg programs to read basic
sock information about the sock they are attached to. The second
patch adds the tests to the selftest test_verifier.

One observation that I had from writing this seriess is lots of the
./net/core/filter.c code is almost duplicated across program types.
I thought about building a template/macro that we could use as a
single block of code to read sock data out for multiple programs,
but I wasn't convinced it was worth it yet. The result was using a
macro saved a couple lines of code per block but made the code
a bit harder to read IMO. We can probably revisit the idea later
if we get more duplication.

v2: add errstr field to negative test_verifier test cases to ensure
    we get the expected err string back from the verifier.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Add tests for BPF_PROG_TYPE_SK_MSG to test_verifier for read access
to new sk fields.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Currently sk_msg programs only have access to the raw data. However,
it is often useful when building policies to have the policies specific
to the socket endpoint. This allows using the socket tuple as input
into filters, etc.

This patch adds ctx access to the sock fields.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Jiong Wang says:

====================
NFP eBPF JIT is missing logic indirect shifts (both left and right) and
arithmetic right shift (both indirect shift and shift by constant).

This patch adds support for them.

For indirect shifts, shift amount is not specified as constant, NFP needs
to get the shift amount through the low 5 bits of source A operand in
PREV_ALU, therefore extra instructions are needed compared with shifts by
constants.

Because NFP is 32-bit, so we are using register pair for 64-bit shifts and
therefore would need different instruction sequences depending on whether
shift amount is less than 32 or not.

NFP branch-on-bit-test instruction emitter is added by this patch set and
is used for efficient runtime check on shift amount. We'd think the shift
amount is less than 32 if bit 5 is clear and greater or equal then 32
otherwise. Shift amount is greater than or equal to 64 will result in
undefined behavior.

This patch also use range info to avoid generating unnecessary runtime code
if we are certain shift amount is less than 32 or not.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Code logic is similar with arithmetic right shift by constant, and NFP
get indirect shift amount through source A operand of PREV_ALU.

It is possible to fall back to logic right shift if the MSB is known to be
zero from range info, however there is no benefit to do this given logic
indirect right shift use the same number and cycle of instruction sequence.

Suppose the MSB of regX is the bit we want to replicate to fill in all the
vacant positions, and regY contains the shift amount, then we could use
single instruction to set up both.

  [alu, --, regY, OR, regX]

  --
  NOTE: the PREV_ALU result doesn't need to write to any destination
        register.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Code logic is similar with logic right shift except we also need to set
PREV_ALU result properly, the MSB of which is the bit that will be
replicated to fill in all the vacant positions.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

For indirect shifts, shift amount is not specified as constant, NFP needs
to get the shift amount through the low 5 bits of source A operand in
PREV_ALU, therefore extra instructions are needed compared with shifts by
constants.

Because NFP is 32-bit, so we are using register pair for 64-bit shifts and
therefore would need different instruction sequences depending on whether
shift amount is less than 32 or not.

NFP branch-on-bit-test instruction emitter is added by this patch and is
used for efficient runtime check on shift amount. We'd think the shift
amount is less than 32 if bit 5 is clear and greater or equal than 32
otherwise. Shift amount is greater than or equal to 64 will result in
undefined behavior.

This patch also use range info to avoid generating unnecessary runtime code
if we are certain shift amount is less than 32 or not.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Björn Töpel says:

====================
This series contain "cosmetics only" follow-up patches for AF_XDP.

Thanks to Daniel for suggesting them!
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Properly align xsk_proto_ops initialization.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Removed some cases of unnecessary parentheses.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Minor cleanup, remove newline at end of Makefile.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Clean up SPDX-License-Identifier and removing licensing leftovers.
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

`e' is being freed twice.

Fix this by removing one of the kfree() calls.

Addresses-Coverity-ID: 1468983 ("Double free")
Fixes: 81110384 ("bpf: sockmap, add hash map support")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

There is a potential execution path in which variable err is
returned without being properly initialized previously.

Fix this by initializing variable err to 0.

Addresses-Coverity-ID: 1468964 ("Uninitialized scalar variable")
Fixes: e5cd3abc ("bpf: sockmap, refactor sockmap routines to work with hashmap")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>