On 10/13/23 3:04 PM, Kuniyuki Iwashima wrote:
This patch adds a test for BPF_SOCK_OPS_(GEN|CHECK)_SYNCOOKIE_CB hooks.
BPF_SOCK_OPS_GEN_SYNCOOKIE_CB hook generates a hash using SipHash from
based on 4-tuple. The hash is split into ISN and TS. MSS, ECN, SACK,
and WScale are encoded into the lower 8-bits of ISN.
ISN:
MSB LSB
| 31 ... 8 | 7 6 | 5 | 4 | 3 2 1 0 |
| Hash_1 | MSS | ECN | SACK | WScale |
TS:
MSB LSB
| 31 ... 8 | 7 ... 0 |
| Random | Hash_2 |
BPF_SOCK_OPS_CHECK_SYNCOOKIE_CB hook re-calculates the hash and validates
the cookie.
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
---
Currently, the validator is incomplete...
If this line is changed
skops->replylong[0] = msstab[3];
to
skops->replylong[0] = msstab[mssind];
, we will get the error below during make:
GEN-SKEL [test_progs] test_tcp_syncookie.skel.h
...
Error: failed to open BPF object file: No such file or directory
I cannot reprod. Does it have error earlier than this? GEN-SKEL is probably
running this (make V=1 can tell):
tools/testing/selftests/bpf/tools/sbin/bpftool gen skeleton
tools/testing/selftests/bpf/test_tcp_syncookie.bpf.linked3.o name
test_tcp_syncookie > tools/testing/selftests/bpf/test_tcp_syncookie.skel.h
Add a "-d" to bpftool for more debug output: bpftool -d gen skeleton....
I cannot compile the patch in my environment as-is also:
In file included from progs/test_tcp_syncookie.c:6:
In file included from
/data/users/kafai/fb-kernel/linux/tools/include/uapi/linux/tcp.h:22:
In file included from /usr/include/asm/byteorder.h:5:
In file included from /usr/include/linux/byteorder/little_endian.h:13:
/usr/include/linux/swab.h:136:8: error: unknown type name '__always_inline'
136 | static __always_inline unsigned long __swab(const unsigned long y)
I have to add a "#include <linux/stddef.h>".
GEN-SKEL [test_progs-no_alu32] test_tcp_syncookie.skel.h
make: *** [Makefile:603: /home/ec2-user/kernel/bpf_syncookie/tools/testing/selftests/bpf/test_tcp_syncookie.skel.h] Error 254
make: *** Deleting file '/home/ec2-user/kernel/bpf_syncookie/tools/testing/selftests/bpf/test_tcp_syncookie.skel.h'
make: *** Waiting for unfinished jobs....
