Use BUG_ON instead of if condition followed by BUG in tcp_time_wait.

This issue was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use BUG_ON instead of if condition followed by BUG in icmp_timestamp.

This issue was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

As pointed out by Michael, commit 1c601d82 ("bpf: cpumap xdp_buff
to skb conversion and allocation") contains a classical example of the
potential lost wake-up problem.

We need to recheck the condition __ptr_ring_empty() after changing
current->state to TASK_INTERRUPTIBLE, this avoids a race between
wake_up_process() and schedule(). After this, a race with
wake_up_process() will simply change the state to TASK_RUNNING, and
the schedule() call not really put us to sleep.

Fixes: 1c601d82 ("bpf: cpumap xdp_buff to skb conversion and allocation")
Reported-by: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case I placed the "fall through" comment
on its own line, which is what GCC is expecting to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Eric Dumazet says:

====================
ipv6: addrconf: hash improvements and cleanups

Remove unecessary BH blocking, and bring IPv6 addrconf to modern world,
with per netns hash perturbation and decent hash size.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

rcu_read_lock() is enough here, no need to block BH.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Table is really RCU protected, no need to block BH
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rcu_read_lock() is enough here, no need to block BH.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rcu_read_lock() is enough here, as inet6_ifa_finish_destroy()
uses kfree_rcu()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Bring IPv6 in par with IPv4 :

- Use net_hash_mix() to spread addresses a bit more.
- Use 256 slots hash table instead of 16
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6_add_addr_hash() can compute the hash value outside of
locked section and pass it to ipv6_chk_same_addr().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

ipv6_chk_same_addr() is only used by ipv6_add_addr_hash(),
so moving it avoids a forward declaration.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jakub Kicinski says:

====================
nfp: bpf: stack support in offload

This series brings stack support for offload.

We use the LMEM (Local memory) register file as memory to store
the stack.  Since this is a register file we need to do appropriate
shifts on unaligned accesses.  Verifier's state tracking helps us
with that.

LMEM can't be accessed directly, so we add support for setting
pointer registers through which one can read/write LMEM.

This set does not support accessing the stack when the alignment
is not known.  This can be added later (most likely using the byte_align
instructions).  There is also a number of optimizations which have been
left out:
 - in more complex non aligned accesses, double shift and rotation
   can save us a cycle.  This, however, leads to code explosion
   since all access sizes have to be coded separately;
 - since setting LM pointers costs around 5 cycles, we should be
   tracking their values to make sure we don't move them when
   they're already set correctly for earlier access;
 - in case of 8 byte access aligned to 4 bytes and crossing
   32 byte boundary but not crossing a 64 byte boundary we don't
   have to increment the pointer, but this seems like a pretty
   rare case to justify the added complexity.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Loading 64bit constants require up to 4 load immediates, since
we can only load 16 bits at a time.  If the 32bit halves of
the 64bit constant are the same, however, we can save a cycle
by doing a register move instead of two loads of 16 bits.

Note that we don't optimize the normal ALU64 load because even
though it's a 64 bit load the upper half of the register is
a coming from sign extension so we can load it in one cycle
anyway.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If stack pointer has a different value on different paths
but the alignment to words (4B) remains the same, we can
set a new LMEM access pointer to the calculated value and
access whichever word it's pointing to.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

To access beyond 64th byte of the stack we need to set a new
stack pointer register (LMEM is accessed indirectly through
those pointers).  Add a function for encoding local CSR access
instruction.  Use stack pointer number 3.

Note that stack pointer registers allow us to index into 32
bytes of LMEM (with shift operations i.e. when operands are
restricted).  This means if access is crossing 32 byte boundary
we must not use offsetting, we have to set the pointer to the
exact address and move it with post-increments.

We depend on the datapath placing the stack base address in
GPR A22 for our use.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

As long as the verifier tells us the stack offset exactly we
can render the LMEM reads quite easily.  Simply make sure that
the offset is constant for a given instruction and add it to
the instruction's offset.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When we are performing unaligned stack accesses in the 32-64B window
we have to do a read-modify-write cycle.  E.g. for reading 8 bytes
from address 17:

0:  tmp    = stack[16]
1:  gprLo  = tmp >> 8
2:  tmp    = stack[20]
3:  gprLo |= tmp << 24
4:  tmp    = stack[20]
5:  gprHi  = tmp >> 8
6:  tmp    = stack[24]
7:  gprHi |= tmp << 24

The load on line 4 is unnecessary, because tmp already contains data
from stack[20].

For write we can optimize both loads and writebacks away.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add simple stack read support, similar to write in every aspect,
but data flowing the other way.  Note that unlike write which can
be done in smaller than word quantities, if registers are loaded
with less-than-word of stack contents - the values have to be
zero extended.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stack is implemented by the LMEM register file.  Unaligned accesses
to LMEM are not allowed.  Accesses also have to be 4B wide.

To support stack we need to make sure offsets of pointers are known
at translation time (for now) and perform correct load/mask/shift
operations.

Since we can access first 64B of LMEM without much effort support
only stacks not bigger than 64B.  Following commits will extend
the possible sizes beyond that.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

nfp_bpf_check_ptr() mostly looks at the pointer register.
Add a temporary variable to shorten the code.

While at it make sure we print error messages if translation
fails to help users identify the problem (to be carried in
ext_ack in due course).
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The need to emitting a few nops will become more common soon
as we add stack and map support.  Add a helper.  This allows
for code to be shorter but also may be handy for marking the
nops with a "reason" to ease applying optimizations.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jakub Kicinski says:

====================
tools: bpftool: Add JSON output to bpftool

Quentin says:

This series introduces support for JSON output to all bpftool commands. It
adds option parsing, and several options are created:

  * -j, --json     Switch to JSON output.
  * -p, --pretty   Switch to JSON and print it in a human-friendly fashion.
  * -h, --help     Print generic help message.
  * -V, --version  Print version number.

This code uses a "json_writer", which is a copy of the one written by
Stephen Hemminger in iproute2.
---
I don't know if there is an easy way to share the code for json_write
without copying the file, so I am very open to suggestions on this matter.
====================
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Update the documentation to provide help about JSON output generation,
and add an example in bpftool-prog manual page.

Also reintroduce an example that was left aside when the tool was moved
from GitHub to the kernel sources, in order to show how to mount the
bpffs file system (to pin programs) inside the bpftool-prog manual page.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Make the look-and-feel of the manual pages somewhat closer to other
manual pages, such as the ones from the utilities from iproute2, by
highlighting more keywords.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

As all commands can now return JSON output (possibly just a "null"
value), output of `bpftool --json batch file FILE` should also be fully
JSON compliant.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Turn err() and info() macros into functions.

In order to avoid naming conflicts with variables in the code, rename
them as p_err() and p_info() respectively.

The behavior of these functions is similar to the one of the macros for
plain output. However, when JSON output is requested, these macros
return a JSON-formatted "error" object instead of printing a message to
stderr.

To handle error messages correctly with JSON, a modification was brought
to their behavior nonetheless: the functions now append a end-of-line
character at the end of the message. This way, we can remove end-of-line
characters at the end of the argument strings, and not have them in the
JSON output.

All error messages are formatted to hold in a single call to p_err(), in
order to produce a single JSON field.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

`bpftool batch file FILE` takes FILE as an argument and executes all the
bpftool commands it finds inside (or stops if an error occurs).

To obtain a consistent JSON output, create a root JSON array, then for
each command create a new object containing two fields: one with the
command arguments, the other with the output (which is the JSON object
that the command would have produced, if called on its own).
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Reuse the json_writer API introduced in an earlier commit to make
bpftool able to generate JSON output on
`bpftool map { show | dump | lookup | getnext }` commands. Remaining
commands produce no output.

Some functions have been spit into plain-output and JSON versions in
order to remain readable.

Outputs for sample maps have been successfully tested against a JSON
validator.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a new printing function to dump translated eBPF instructions as
JSON. As for plain output, opcodes are printed only on request (when
`opcodes` is provided on the command line).

The disassembled output is generated by the same code that is used by
the kernel verifier.

Example output:

    $ bpftool --json --pretty prog dump xlated id 1
    [{
            "disasm": "(bf) r6 = r1"
        },{
            "disasm": "(61) r7 = *(u32 *)(r6 +16)"
        },{
            "disasm": "(95) exit"
        }
    ]

    $ bpftool --json --pretty prog dump xlated id 1 opcodes
    [{
            "disasm": "(bf) r6 = r1",
            "opcodes": {
                "code": "0xbf",
                "src_reg": "0x1",
                "dst_reg": "0x6",
                "off": ["0x00","0x00"
                ],
                "imm": ["0x00","0x00","0x00","0x00"
                ]
            }
        },{
            "disasm": "(61) r7 = *(u32 *)(r6 +16)",
            "opcodes": {
                "code": "0x61",
                "src_reg": "0x6",
                "dst_reg": "0x7",
                "off": ["0x10","0x00"
                ],
                "imm": ["0x00","0x00","0x00","0x00"
                ]
            }
        },{
            "disasm": "(95) exit",
            "opcodes": {
                "code": "0x95",
                "src_reg": "0x0",
                "dst_reg": "0x0",
                "off": ["0x00","0x00"
                ],
                "imm": ["0x00","0x00","0x00","0x00"
                ]
            }
        }
    ]
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Reuse the json_writer API introduced in an earlier commit to make
bpftool able to generate JSON output on `bpftool prog show *` commands.
A new printing function is created to be passed as an argument to the
disassembler.

Similarly to plain output, opcodes are printed on request.

Outputs from sample programs have been successfully tested against a
JSON validator.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Reuse the json_writer API introduced in an earlier commit to make
bpftool able to generate JSON output on `bpftool prog show *` commands.

For readability, the code from show_prog() has been split into two
functions, one for plain output, one for JSON.

Outputs from sample programs have been successfully tested against a
JSON validator.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

These two options can be used to ask for a JSON output (--j or -json),
and to make this JSON human-readable (-p or --pretty).

A json_writer object is created when JSON is required, and will be used
in follow-up commits to produce JSON output.

Note that --pretty implies --json.

Update for the manual pages and interactive help messages comes in a
later patch of the series.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add an option parsing facility to bpftool, in prevision of future
options for demanding JSON output. Currently, two options are added:
--help and --version, that act the same as the respective commands
`help` and `version`.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

In prevision of following commits, supposed to add JSON output to the
tool, two files are copied from the iproute2 repository (taken at commit
268a9eee985f): lib/json_writer.c and include/json_writer.h.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Song Liu says:

====================
net: add a set of tracepoints to tcp stack

Changes from v1:

Fix build error (with ipv6 as ko) by adding EXPORT_TRACEPOINT_SYMBOL_GPL
for trace_tcp_send_reset.

These patches add the following tracepoints to tcp stack.

tcp_send_reset
tcp_receive_reset
tcp_destroy_sock
tcp_set_state

These tracepoints can be used to track TCP state changes. Such state
changes include but are not limited to: connection establish,
connection termination, tx and rx of RST, various retransmits.

Currently, we use the following kprobes to trace these events:

int kprobe__tcp_validate_incoming
int kprobe__tcp_send_active_reset
int kprobe__tcp_v4_send_reset
int kprobe__tcp_v6_send_reset
int kprobe__tcp_v4_destroy_sock
int kprobe__tcp_set_state
int kprobe__tcp_retransmit_skb

These tracepoints will help us simplify this work.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds tracepoint trace_tcp_set_state. Besides usual fields
(s/d ports, IP addresses), old and new state of the socket is also
printed with TP_printk, with __print_symbolic().
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds trace event trace_tcp_destroy_sock.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

New tracepoint trace_tcp_receive_reset is added and called from
tcp_reset(). This tracepoint is define with a new class tcp_event_sk.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>